From a2e16ce3afeddce71edffb6f6509bd7648735a6b Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Wed, 20 Jul 2022 16:33:45 +0800
Subject: [PATCH 01/13] Update to endpoint mode

---
 docs/glossary.md                              |   4 +
 docs/sdk/constants.md                         |  22 ++
 .../03-build-your-first-cross-chain-dapp.md   | 198 +++++++---------
 .../guides/04-call-smart-contract-remotely.md | 215 ++++++------------
 4 files changed, 172 insertions(+), 267 deletions(-)
 create mode 100644 docs/sdk/constants.md

diff --git a/docs/glossary.md b/docs/glossary.md
index 7ac84f08..587a79d4 100644
--- a/docs/glossary.md
+++ b/docs/glossary.md
@@ -8,6 +8,10 @@ sidebar_position: 4
 
 Decentralized application.
 
+## Endpoint
+
+The cross-chain operation entry. An endpoint is a deployed smart contract which is used by Dapps to do cross-chain operations. 
+
 ## Dapp developer
 
 Dapp developers include those who develop applications based on the Darwinia Smart Contracts module, as well as those who develop Dapps on public chains, such as blockchain games or Defi applications on platforms such as Ethereum, TRON or EOS.
diff --git a/docs/sdk/constants.md b/docs/sdk/constants.md
new file mode 100644
index 00000000..9c48ac74
--- /dev/null
+++ b/docs/sdk/constants.md
@@ -0,0 +1,22 @@
+---
+sidebar_position: 6
+---
+
+# Constants
+
+
+## Chain Identifiers
+
+    bytes4 constant _DARWINIA_CHAIN_ID = 0x64617277; // darw
+    bytes4 constant _CRAB_CHAIN_ID = 0x63726162; // crab
+    bytes4 constant _PANGORO_CHAIN_ID = 0x70616772; // pagr
+    bytes4 constant _PANGOLIN_CHAIN_ID = 0x7061676c; // pagl
+    bytes4 constant _PANGOLIN_PARACHAIN_CHAIN_ID = 0x70676c70; // pglp
+    bytes4 constant _CRAB_PARACHAIN_CHAIN_ID = 0x63726170; // crap
+
+## Lane Identifiers
+
+    bytes4 constant _DARWINIA_CRAB_LANE_ID = 0x00000000;
+    bytes4 constant _PANGORO_PANGOLIN_LANE_ID = 0x726f6c69; // roli
+    bytes4 constant _PANGOLIN_PANGOLIN_PARACHAIN_LANE_ID = 0x70616c69; // pali
+    bytes4 constant _CRAB_CRAB_PARACHAIN_LANE_ID = 0x70616372; // pali
\ No newline at end of file
diff --git a/docs/sdk/guides/03-build-your-first-cross-chain-dapp.md b/docs/sdk/guides/03-build-your-first-cross-chain-dapp.md
index d4fed7dc..7e0956e0 100644
--- a/docs/sdk/guides/03-build-your-first-cross-chain-dapp.md
+++ b/docs/sdk/guides/03-build-your-first-cross-chain-dapp.md
@@ -2,157 +2,121 @@
 sidebar_position: 3
 ---
 
-# Build your first cross-chain Dapp
+# Build Your First Cross-chain Dapp
 
-We will use [hardhat](https://hardhat.org/) to build our first cross-chain Dapp. The Dapp will be deployed to the Pangoro Smart Chain, then call the `remark_with_event` on the [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) remotely.
+This Dapp allows you to call Pangolin's `remark_with_event` cross-chain from Pangoro.
 
-## Preparation
+## Install deps
 
-1. Go to an empty folder, running `npm init`
-2. `npm install --save-dev hardhat`
-3. `npm install --save @darwinia/contracts-periphery`
+`npm install --save-dev @darwinia/contracts-periphery @darwinia/contracts-utils`
 
-Now, we have a hardhat project with Darwinia SDK.
+## Prepare your cross-chain endpoint
 
-## Create Scale Types (Optional)
+Extends the `MessageEndpoint` contract to create your own endpoint. In your contracts folder, create a file `ToPangolinEndpoint.sol`.
 
-If there is no existing Scale Types for the target chain, you need to define the types yourself. You can find the existing types in `@darwinia/contracts-utils`. Here, Darwinia is our target chain. We need to define the remark dispatch call type.
+```javascript
+// SPDX-License-Identifier: MIT
 
-Create a new file named `PalletSystem.sol` in your contracts folder and copy and paste the code below into it.
+pragma solidity ^0.8.9;
+
+import "@darwinia/contracts-periphery/contracts/s2s/MessageEndpoint.sol";
+
+contract ToPangolinEndpoint is MessageEndpoint {
+    constructor() {
+        outboundLaneId = 0x726f6c69;
+        inboundLaneId = 0x726f6c69;
+        storageAddress = address(1024);
+        dispatchAddress = address(1025);
+        storageKeyForMarketFee = 0x30d35416864cf657db51d3bc8505602f2edb70953213f33a6ef6b8a5e3ffcab2;
+        storageKeyForLatestNonce = 0xd86d7f611f4d004e041fda08f633f10196c246acb9b55077390e3ca723a0ca1f;
+        storageKeyForLastDeliveredNonce = 0xd86d7f611f4d004e041fda08f633f101e5f83cf83f2127eb47afdc35d6e43fab;
+        sendMessageCallIndex = 0x1103;
+        remoteMessageTransactCallIndex = 0x2901;
+        remoteSmartChainId = 43;
+    }
 
-```solidity
-library PalletSystem {
-    struct RemarkCall {
-        bytes2 callIndex;
-        bytes remark;
+    function _canBeExecuted(address, bytes calldata)
+        internal
+        pure
+        override
+        returns (bool)
+    {
+        return true;
     }
 
-    function encodeRemarkCall(RemarkCall memory call) internal pure returns (bytes memory) {
-        return abi.encodePacked(
-            call.callIndex, 
-            ScaleCodec.encodeBytes(call.remark)
-        );
+    function remoteDispatch(
+        uint32 pangolinSpecVersion,
+        bytes memory pangolinCallEncoded,
+        uint64 pangolinCallWeight
+    ) external payable returns (uint256) {
+        return
+            _remoteDispatch(
+                pangolinSpecVersion,
+                pangolinCallEncoded,
+                pangolinCallWeight
+            );
     }
 }
 ```
 
-`remark_with_event` is the function(dispatch call) on the Pangolin that will be cross-chain called. The `System.RemarkCall` type is used to encode it.
+Deploy it on the Pangoro Smart Chain. The `remoteDispatch` will be used in the next step.
 
-Darwinia SDK will provide the most common types for you. If you want to learn more about the Scale Codec, please visit https://docs.substrate.io/v3/advanced/scale-codec/.
+You can download the completed [ToPangolinEndpoint.sol](https://raw.githubusercontent.com/darwinia-network/darwinia-messages-sol/master/contracts/periphery/contracts/s2s/examples/ToPangolinEndpoint.sol), and add your own access controls to it if your want to use it in a production environment.
 
-## Create your Dapp
+## Create your Dapp contract
 
-Darwinia SDK provides a abstract base Dapp contract named `PangoroXApp`. You should extends it to create your Dapp contract. In your contracts folder, create a file `RemarkDemo.sol`.
+In your contracts folder, create a file `RemarkDemo.sol`.
 
 ```javascript
 // SPDX-License-Identifier: MIT
 
-pragma solidity >=0.6.0;
+pragma solidity ^0.8.9;
+
+import "./ToPangolinEndpoint.sol";
+import "@darwinia/contracts-periphery/contracts/s2s/types/PalletSystem.sol";
 
-import "@darwinia/contracts-periphery/contracts/s2s/SmartChainXApp.sol";
-import "./System.sol";
+contract RemarkDemo {
+    address public endpoint;
 
-contract RemarkDemo is PangoroXApp {
-    constructor() public {
-        init();
+    constructor(address _endpoint) {
+        endpoint = _endpoint;
     }
 
-    function remark() public payable {
-        // 1. prepare the call that will be executed on the target chain
-        System.RemarkCall memory call = System.RemarkCall(
-            hex"0009", // the call index of remark_with_event
-            hex"12345678"
+    function remoteRemark(bytes memory _remark)
+        external
+        payable
+        returns (uint256)
+    {
+        // 1. Prepare the call and its weight which will be executed on the target chain
+        PalletSystem.RemarkCall memory call = PalletSystem.RemarkCall(
+            hex"0009",
+            _remark
         );
-        bytes memory callEncoded = System.encodeRemarkCall(call);
-
-        // 2. Prepare the message payload
-        MessagePayload memory payload = MessagePayload(
-            1210, // spec version of target chain
-            2654000000, // call weight
-            callEncoded // call encoded bytes
+        bytes memory encodedCall = PalletSystem.encodeRemarkCall(call);
+        uint64 weight = uint64(_remark.length * 2_000);
+
+        // 2. Dispatch the call
+        uint256 messageId = ToPangolinEndpoint(endpoint).remoteDispatch{
+            value: msg.value
+        }(
+            28140, // latest spec version of pangolin
+            encodedCall,
+            weight
         );
 
-        // 3. Send the message payload to the pangolin through the lane id
-        bytes4 laneId = 0;
-        uint64 _messageNonce = sendMessage(toPangolin, laneId, payload);
+        return messageId;
     }
 }
 ```
 
-Note: 
-
-1. The spec version of the `MessagePayload` must be correct, you can get the latest spec version from https://pangolin.subscan.io/runtime.
-
-3. The call weight of the `MessagePayload` must be equal to or greater than the expected weight. you can get it from the target chain's benchmarks.
-
-
-## Run in Remix
-
-The easiest way to run the code is [Remix](https://remix.ethereum.org/).
-
-1. [Connect your MetaMask to Pangoro](./01-using-smart-chain-with-metamask.md).
-2. Export you Dapp to a single flattened solidity file.
-    
-    ```bash
-    npx hardhat flatten ./contracts/RemarkDemo.sol > ~/Desktop/RemarkDemo.sol
-    ```
-    
-3. Copy it to Remix and deploy the `RemarkDemo` contract.
-4. Run `systemRemark` with value 200 ethers(here means ORINGs), the value must ≥ the [market fee](../../fee.md). important!
-
-## Or, Run in your project with hardhat command
-
-1. Open your `hardhat.config.js` in your project folder, add Crab Network into `networks`.
-
-    ```js
-    crab: {
-      url: 'https://pangoro-rpc.darwinia.network',
-      network_id: "45",
-      accounts: [PRIVATE_KEY],
-      gas: 3_000_000,
-      gasPrice: 53100000000
-    }
-    ```
-    PRIVATE_KEY is your private key of Crab Network account with enough(≥ market fee + transaction fee) ORINGs tokens.
-
-2. Add a script to deploy and run your contract. Inside `scripts/`, create a new file `remarkdemo-script.js` with the following code:
-
-    ```js
-    const hre = require("hardhat");
-
-    async function main() {
-        // We get the contract to deploy
-        const RemarkDemo = await hre.ethers.getContractFactory("RemarkDemo");
-        const demo = await RemarkDemo.deploy();
-        await demo.deployed();
-        await demo.deployTransaction.wait();
-        console.log("Deployed to:", demo.address);
-
-        // Send transaction
-        const tx = await demo.remark({
-          value: BigInt(200000000000000000000), // 200 CRAB, The fee to use the cross-chain service, determined by the Fee Market
-        });
-        await tx.wait();
-        console.log("txhash:", tx["hash"]);
-    }
-
-    main()
-      .then(() => process.exit(0))
-      .catch((error) => {
-        console.error(error);
-        process.exit(1);
-      });
-    ```
-
-3. Run
+Make sure that the latest spec version of pangolin is correct. You can get it from https://pangolin.subscan.io/runtime.
 
-    In your project's folder, run:
+Deploy the Dapp contract on the Pangoro Smart Chain. Inject the endpoint address from previous step into the Dapp contract during its initialization.
 
-    ```bash
-    npx hardhat run --network crab scripts/remarkdemo-script.js
-    ```
+## Run
 
-    It will output the txhash of the transaction. You can copy it to [subscan](https://pangoro.subscan.io/) to see the detail of the transaction. 
+1. You can get a estimated fee by calling the `fee` function of the endpoint contract.
+2. Call the `remoteRemark` with a value. The value should greater than or equal to the estimated fee.
 
 ## Track cross-chain events with subscan
 
@@ -160,7 +124,7 @@ The easiest way to run the code is [Remix](https://remix.ethereum.org/).
 
 [https://pangoro.subscan.io/event?address=&module=bridgedarwiniamessages&event=all](https://crab.subscan.io/event?address=&module=bridgedarwiniamessages&event=all)
 
-### MessageDelivered events of Pangolin
+### MessageDispatched events of Pangolin
 
 [https://pangolin.subscan.io/event?address=&module=bridgecrabmessages&event=all](https://darwinia.subscan.io/event?address=&module=bridgecrabmessages&event=all)
 
diff --git a/docs/sdk/guides/04-call-smart-contract-remotely.md b/docs/sdk/guides/04-call-smart-contract-remotely.md
index 1d56a6bc..4d10a1c9 100644
--- a/docs/sdk/guides/04-call-smart-contract-remotely.md
+++ b/docs/sdk/guides/04-call-smart-contract-remotely.md
@@ -4,170 +4,85 @@ sidebar_position: 4
 
 # Call Smart Contract Remotely
 
-Darwinia supports calling smart contracts on the target chain from the source chain, and currently supports solidity smart contracts.
+This Dapp allows you to call Pangolin Smart Chain's `add(2)` function from Pangoro.
 
-Calling a solidity function remotely is similar to calling a normal call, except that 1. You need to deploy a contract to the smart chain of the target chain. 2. Use a specific type of call `PalletEthereum.TransactCall`.
+## Install deps
 
-Here are the steps:
+`npm install --save-dev @darwinia/contracts-periphery @darwinia/contracts-utils`
 
-1. Prepare your smart contract to be deployed on the target chain
+## Prepare your cross-chain endpoints
 
-    ```javascript
-    contract TargetContract {
-        uint256 public number;
+We need two endpoints here. One is for Pangoro, and the another one is for Pangolin. We can download them here.
 
-        function add(uint256 _value) public {
-            number = number + _value;
-        }
-    }
-    ```
-
-    After deployed, the contract address will be used in the next step.
-
-2. Prepare your smart contract to be deployed on the source chain
-
-    This step is similar to the one in the [previous guide](./build-your-first-cross-chain-dapp), except we are using a specific type of Call. The definition of this call is as follows:
-
-    ```js
-    contract RemoteTransactDemo is PangoroXApp {
-        ...
-        
-        function callAddOnTargetChain() public payable {
-            // 1. prepare the call that will be executed on the target chain
-            PalletEthereum.TransactCall memory call = PalletEthereum.TransactCall(
-                // the call index of substrate_transact
-                0x2902,
-                // the evm transaction to transact
-                PalletEthereum.buildTransactionV2(
-                    0, // evm tx nonce, nonce on the target chain + pending nonce on the source chain + 1
-                    1000000000, // gasPrice, get from the target chain
-                    600000, // gasLimit, get from the target chain
-                    0x50275d3F95E0F2FCb2cAb2Ec7A231aE188d7319d, // <------------------ the contract address on the target chain
-                    0, // value, the only allowed value here is 0
-                    hex"1003e2d20000000000000000000000000000000000000000000000000000000000000002" // the add function bytes that will be called on the target chain, add(2)
-                )
-            );
-            bytes memory callEncoded = PalletEthereum.encodeTransactCall(call);
-
-            // 2. Prepare the message payload
-            MessagePayload memory payload = MessagePayload(
-                28110, // spec version of target chain <----------- This may be changed, go to https://pangoro.subscan.io/runtime get the latest spec version
-                2654000000, // call weight
-                callEncoded // call encoded bytes
-            );
-
-            // 3. Send the message payload to the pangolin through the lane id
-            bytes4 laneId = 0;
-            uint64 _messageNonce = sendMessage(toPangolin, laneId, payload);
-        }
-
-        ...
-    }
+1. Download [ToPangolinEndpoint.sol](https://raw.githubusercontent.com/darwinia-network/darwinia-messages-sol/master/contracts/periphery/contracts/s2s/examples/ToPangolinEndpoint.sol) for Pangoro. Then deploy it to Pangoro Smart Chain.
+
+2. Download [ToPangoroEndpoint.sol](https://raw.githubusercontent.com/darwinia-network/darwinia-messages-sol/master/contracts/periphery/contracts/s2s/examples/ToPangoroEndpoint.sol) for Pangolin. Then deploy it to Pangolin Smart Chain. 
+
+3. Call the `setRemoteEndpoint(_remoteChainId, _remoteEndpoint)` of the two endpoints to point to each other. 
+
+The chain id of Pangoro is `0x70616772`. The chain id of `Pangolin` is 0x7061676c.  
+
+You can get the full chain id list from [constants](../constants).
+
+## Create the callee contract on Pangolin
+
+In your contracts folder, create a file `Callee.sol`.
+
+```javascript
+// SPDX-License-Identifier: MIT
 
-    ```
-
-    Note:
-
-    It follows the notes of [previous guide](./build-your-first-cross-chain-dapp#create-your-dapp). And, There are two more rules to note:
-
-    1. `weight` of MessagePayload >= gas_to_weight(`gasLimit` of buildTransactionV2)
-
-    2. `gasPrice` of buildTransactionV2 >= WeightToFee::calc(gas_to_weight(1)) * next_fee_multiplier * 10**9
-
-    3. `nonce` of buildTransactionV2 is evm tx nonce.
-
-# Restricted access
-
-If you want to restrict your method to only be called remotely by your Dapp contract, you need to do something like this:
-
-1. Prepare your Dapp contract for both source chain and target chain
-
-    ```js
-    // deploy on the target chain first, then deploy on the source chain
-    contract RemoteTransactDemo is PangolinXApp {
-        constructor() public {
-            init();
-        }
-
-        uint256 public number;
-
-        ///////////////////////////////////////////
-        // used on the source chain
-        ///////////////////////////////////////////
-        function callAddOnTheTargetChain() public payable {
-            // 1. prepare the call that will be executed on the target chain
-            PalletEthereum.TransactCall memory call = PalletEthereum.TransactCall(
-                // the call index of substrate_transact
-                0x2902,
-                // the evm transaction to transact
-                PalletEthereum.buildTransactionV2(
-                    0, // evm tx nonce, nonce on the target chain + pending nonce on the source chain + 1
-                    1000000000, // gasPrice, get from the target chain
-                    600000, // gasLimit, get from the target chain
-                    0x50275d3F95E0F2FCb2cAb2Ec7A231aE188d7319d, // <------------------ change to the contract address on the target chain
-                    0, // value, the only allowed value here is 0
-                    hex"1003e2d20000000000000000000000000000000000000000000000000000000000000002" // the add function bytes that will be called on the target chain, add(2)
-                )
-            );
-            bytes memory callEncoded = PalletEthereum.encodeTransactCall(call);
-
-            // 2. Prepare the message payload
-            MessagePayload memory payload = MessagePayload(
-                28110, // spec version of target chain <----------- This may be changed, go to https://pangoro.subscan.io/runtime get the latest spec version
-                2654000000, // call weight
-                callEncoded // call encoded bytes
-            );
-
-            // 3. Send the message payload to the pangolin through the lane id
-            bytes4 laneId = 0;
-            uint64 _messageNonce = sendMessage(toPangolin, laneId, payload);
-        }
-
-        ///////////////////////////////////////////
-        // used on the target chain
-        ///////////////////////////////////////////
-        function add(uint256 _value) public {
-            // this 'require' makes this function only be called by the dapp contract on the source chain
-            require(
-                msg.sender == deriveSenderFromRemote(),
-                "msg.sender must equal to the address derived from the message sender address on the source chain"
-            );
-            number = number + _value;
-        }
+pragma solidity ^0.8.9;
+
+contract Callee {
+    uint256 public sum;
+
+    function add(uint256 _value) external {
+        sum = sum + _value;
     }
-    ```
+}
+```
+
+Deploy it on the Pangolin Smart Chain.
+
+## Create the caller contract on Pangoro
+
+In your contracts folder, create a file `ExecuteDemo.sol`.
 
-2. Deploy the contract to the target chain.
+```javascript
+// SPDX-License-Identifier: MIT
 
-    After deployed, the target chain contract address will be used in the next step.
+pragma solidity ^0.8.9;
 
-3. Deploy the contract to the source chain.
+import "./ToPangolinEndpoint.sol";
 
-    Before deployment, you need to change the target chain contract address first.
+// Call Pangolin.callee.add(2) from Pangoro
+contract ExecuteDemo {
+    address public endpoint;
 
-    ```js
-    PalletEthereum.TransactCall memory call = PalletEthereum.TransactCall(
-        // the call index of substrate_transact
-        0x2902,
-        // the evm transaction to transact
-        PalletEthereum.buildTransactionV2(
-            0, // evm tx nonce, nonce on the target chain + pending nonce on the source chain + 1
-            1000000000, // gasPrice, get from the target chain
-            600000, // gasLimit, get from the target chain
-            0x50275d3F95E0F2FCb2cAb2Ec7A231aE188d7319d, // <------------------ the contract address on the target chain
-            0, // value, the only allowed value here is 0
-            hex"1003e2d20000000000000000000000000000000000000000000000000000000000000002" // the add function bytes that will be called on the target chain, add(2)
-        )
-    );
-    ```
+    constructor(address _endpoint) {
+        endpoint = _endpoint;
+    }
+
+    function remoteAdd(address callee) external payable returns (uint256) {
+        uint256 messageId = ToPangolinEndpoint(endpoint).remoteExecute(
+            28140, // latest spec version of pangolin
+            callee,
+            hex"1003e2d20000000000000000000000000000000000000000000000000000000000000002", // add(2)
+            120000 // gas limit
+        );
+
+        return messageId;
+    }
+}
+```
 
-    After deployed, the source chain contract address will be used in the next step.
+Deploy it on the Pangoro Smart Chain. 
 
-4. Call `setMessageSenderOnSrcChain` to update the source chain contract address on the target chain
+Make sure that the endpoint are correct, it must be the ToPangolinEndpoint's address.
 
-    ```js
-    function setMessageSenderOnSrcChain(address _messageSenderOnSrcChain)
-    ```
+Make sure that the latest spec version of pangolin is correct. You can get it from https://pangolin.subscan.io/runtime.
 
+## Run
 
-After these steps, the `add` function can only be called by `_messageSenderOnSrcChain`.
\ No newline at end of file
+1. You can get a estimated fee by calling the `fee` function of the ToPangolinEndpoint contract.
+2. Call the `remoteAdd(callee)` with a value. The value should greater than or equal to the estimated fee.
\ No newline at end of file

From 1788cdedbdccafcbc13d6f241d1bbe11c87dcf24 Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Thu, 21 Jul 2022 11:21:25 +0800
Subject: [PATCH 02/13] Update api reference

---
 docs/sdk/api-reference.md | 231 +++++++++++++++++++++-----------------
 1 file changed, 131 insertions(+), 100 deletions(-)

diff --git a/docs/sdk/api-reference.md b/docs/sdk/api-reference.md
index bc992bdc..dd8ae657 100644
--- a/docs/sdk/api-reference.md
+++ b/docs/sdk/api-reference.md
@@ -4,139 +4,170 @@ sidebar_position: 1
 
 # API Reference
 
-### Initialization 
+## _remoteDispatch
 
-Before you start using the SDK, you need to set some globle settings in your initialization function.
+Dispatch a substrate call of the target chain. 
+
+This is an internal function to be called by the concrete endpoint functions.
 
 ```javascript
-contract Demo is SmartChainXApp {
-    constructor() public {
-        // Globle settings for Pangolin
-        dispatchAddress = 0x0000000000000000000000000000000000000019;
-        callIndexOfSendMessage = 0x2b03;
-        storageAddress = 0x000000000000000000000000000000000000001a;
-        callbackSender = 0x6461722f64766D70000000000000000000000000;
-    }
-    ...
-}
+function _remoteDispatch(
+    uint32 tgtSpecVersion,
+    bytes memory tgtCallEncoded,
+    uint64 tgtCallWeight
+) internal returns (uint256)
+```
+### Params:    
+
+* tgtSpecVersion: The target chain's latest spec version.
+* tgtCallEncoded: The call to be dispatched on the target chain. It is a SCALE codec bytes.
+* tgtCallWeight: The weight of the call.
+
+### Return:
+
+* message id
+
+## _remoteTransact
+
+Transact a evm call of the endpoint contract on the target chain.
+
+This is an internal function to be called by the concrete endpoint functions.
+
+```javascript
+function _remoteTransact(
+    uint32 tgtSpecVersion,
+    bytes memory callPayload,
+    uint256 gasLimit
+) internal returns (uint256) 
 
 ```
-If not set, the default is the settings of the Crab Network.
+### Params:    
+
+* tgtSpecVersion: The target chain's latest spec version.
+* callPayload: The evm call to be transact on the target chain. It is a ABI codec bytes.
+* gasLimit: The gas limit to run the evm call.
 
+### Return:
 
-### (Source Chain) sendMessage
+* message id
 
-Send a message through a bridge.
+## _remoteExecute
+
+Execute a evm call of the target chain. The difference between the `_remoteExecute` and `_remoteTransact` is that `_remoteTransact` can only call functions of the remote endpoint, but `_remoteExecute` can call functions of other contracts as long as you allow.
+
+This is an internal function to be called by the concrete endpoint functions.
 
 ```javascript
-/// @notice Send message over a bridge
-/// @param bridge The bridge to send message
-/// @param payload The message payload to be sent
-/// @return nonce The nonce of the message
-function sendMessage(Bridge memory bridge, MessagePayload memory payload)
-    internal
-    returns (uint64)
+function _remoteExecute(
+    uint32 tgtSpecVersion,
+    address callReceiver,
+    bytes calldata callPayload,
+    uint256 gasLimit
+) internal returns (uint256)
 ```
+### Params:    
+
+* tgtSpecVersion: The target chain's latest spec version.
+* callReceiver: The contract address which has the function to be called.
+* callPayload: The evm call to be execute on the target chain. It is a ABI codec bytes.
+* gasLimit: The gas limit to run the evm call.
+
+### Return:
+
+* message id
 
-Define the bridge to send message through:
+## fee
+
+Get the estimated cross-chain market fee.
 
 ```javascript
-struct Bridge {
-    // The lane id
-    bytes4 srcOutlaneId;
-    // The storage key used to get market fee
-    bytes srcStorageKeyForMarketFee;
-    // The storage key used to get latest nonce
-    bytes srcStorageKeyForLatestNonce;
-}
+function fee() public view returns (uint256)
 ```
 
-Crab's bridges:
-1. To Darwinia bridge
-    ```javascript
-    Bridge memory bridge = Bridge(
-        // outlane id, lane to Darwinia
-        0,
-        // storage key for Darwinia market fee
-        hex"190d00dd4103825c78f55e5b5dbf8bfe2edb70953213f33a6ef6b8a5e3ffcab2",
-        // storage key for the latest nonce of Darwinia message lane
-        hex"c9b76e645ba80b6ca47619d64cb5e58d96c246acb9b55077390e3ca723a0ca1f11d2df4e979aa105cf552e9544ebd2b500000000"
-    );
-    ```
-
-Pangolin's bridges:
-1. To Pangoro bridge
-    ```javascript
-    Bridge memory bridge = Bridge(
-        // outlane id, lane to Darwinia
-        0,
-        // storage key for Darwinia market fee
-        hex"190d00dd4103825c78f55e5b5dbf8bfe2edb70953213f33a6ef6b8a5e3ffcab2",
-        // storage key for the latest nonce of Darwinia message lane
-        hex"c9b76e645ba80b6ca47619d64cb5e58d96c246acb9b55077390e3ca723a0ca1f11d2df4e979aa105cf552e9544ebd2b500000000"
-    );
-    ```
-    
-### (Source Chain) onMessageDelivered
-
-You need to implement this virtual function If you want to do something after the message is confirmed.
+### Return:
+
+* the estimated cross-chain market fee. The decimals is 18.
+
+## modifier onlyMessageSender
+
+This modifier is used to restrict a function to be called only by the remote sender.
 
 ```javascript
-/// @notice Callback function for 'send_message'
-/// @param lane Lane id
-/// @param nonce Nonce of the callback message
-/// @param result Dispatch result of cross chain message
-function onMessageDelivered(
-    bytes4 lane,
-    uint64 nonce,
-    bool result
-) external virtual;
+modifier onlyMessageSender()
 ```
 
-If you don't want this function to be wrongly called, you should add a check to the first line of your implemention like this,
+## execute
+
+This external function is called remotely to execute an evm call.
+
+It is the mate of `_remoteExecute`.
 
 ```javascript
-contract RemarkDemo is SmartChainXApp {
-    ...
-
-    function onMessageDelivered(
-        bytes4 lane,
-        uint64 nonce,
-        bool result
-    ) external override {
-        require(msg.sender == callbackSender, "Only pallet address is allowed call 'onMessageDelivered'");
-        // TODO: Your code goes here...
-    }
-}
+function execute(address callReceiver, bytes calldata callPayload)
+    external
+    onlyMessageSender
 ```
 
-Callback sender list:
+## _canBeExecuted
 
-### (Target Chain) requireSenderOfSourceChain
+This is an internal virtual function to be overrided.
 
-When a function on the target chain is called by source chain, in order to ensure that this function can only be called by the sender on the source chain, this check needs to be added to the first line of the function.
+It is used to check if a call can be executed on the receiver contract.
 
 ```javascript
-/// @notice This function is used to check the sender.
-/// @param srcChainId The source chain id
-/// @param sender The sender of the message on the source chain
-function requireSenderOfSourceChain(bytes4 srcChainId, address sender)
+function _canBeExecuted(address callReceiver, bytes calldata callPayload)
     internal
+    view
+    virtual
+    returns (bool)
 ```
 
-example:
+## lastDeliveredMessageId
+
+Get the last delivered **inbound** message id.
 
 ```javascript
-contract Demo is SmartChainXApp {
-    uint256 public number;
+function lastDeliveredMessageId() public view returns (uint256)
+```
+
+### Return:
+
+* The last delivered inbound message id
+
+## isMessageDelivered
+
+Check if an **inbound** message has been delivered.
+
+```javascript
+function isMessageDelivered(uint256 messageId) public view returns (bool)
+```
+
+### Params:    
 
-    // this `add` function will be called by `0x6Be02d1d3665660d22FF9624b7BE0551ee1Ac91b` on source chain
-    function add(uint256 _value) public {
-        requireSenderOfSourceChain(0, 0x6Be02d1d3665660d22FF9624b7BE0551ee1Ac91b);
-        number = number + _value;
-    }
+* messageId: The inbound message id.
+
+## encodeMessageId
+
+Build a message by encoding a lane id and a message nonce.
+
+```javascript
+function encodeMessageId(bytes4 laneId, uint64 nonce)
+    public
+    pure
+    returns (uint256)
+```
+
+## decodeMessageId
+
+Decode a message into a lane id and a message nonce.
+
+```javascript
+function decodeMessageId(uint256 messageId)
+    public
+    pure
+    returns (bytes4, uint64)
+```
 
-    ...
-}
+### Params:    
 
-```
\ No newline at end of file
+* messageId: The inbound message id.
\ No newline at end of file

From 6746ced68ab7af6192edbce10e9a1d4b77ef1310 Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Thu, 21 Jul 2022 16:40:27 +0800
Subject: [PATCH 03/13] Fix

---
 docs/glossary.md                              | 34 ++++++++++++-------
 docs/sdk/api-reference.md                     | 17 ++++++++++
 docs/sdk/constants.md                         |  5 ++-
 ... 03-execute-remote-smart-contract-call.md} | 10 +++---
 ...d => 04-dispatch-remote-substrate-call.md} | 24 +++++--------
 5 files changed, 56 insertions(+), 34 deletions(-)
 rename docs/sdk/guides/{04-call-smart-contract-remotely.md => 03-execute-remote-smart-contract-call.md} (84%)
 rename docs/sdk/guides/{03-build-your-first-cross-chain-dapp.md => 04-dispatch-remote-substrate-call.md} (81%)

diff --git a/docs/glossary.md b/docs/glossary.md
index 587a79d4..78e695ea 100644
--- a/docs/glossary.md
+++ b/docs/glossary.md
@@ -1,24 +1,32 @@
 ---
-sidebar_position: 4
+sidebar_position: 7
 ---
 
 # Glossary
 
-## Dapp
-
-Decentralized application.
-
 ## Endpoint
 
-The cross-chain operation entry. An endpoint is a deployed smart contract which is used by Dapps to do cross-chain operations. 
+The cross-chain operation entry. An endpoint is a smart contract which is used by Dapps to do cross-chain operations. 
 
-## Dapp developer
+The endpoint contract is created and deployed by the Dapp developer. After that Dapp can call the endpoint to do cross-chain operations.
 
-Dapp developers include those who develop applications based on the Darwinia Smart Contracts module, as well as those who develop Dapps on public chains, such as blockchain games or Defi applications on platforms such as Ethereum, TRON or EOS.
+```js
+contract YourEndpoint is MessageEndpoint {...}
+```
 
-## Dapp user
+```js
+contract YourDapp {
+    YourEndpoint endpoint;
 
-End users of Dapps.
+    constructor(YourEndpoint _endpoint) {
+        endpoint = _endpoint;
+    }
+   
+    function foo() {
+        YourEndpoint(endpoint).remoteExecute(...);
+    }
+}
+```
 
 ## Source Chain
 
@@ -53,11 +61,11 @@ The message is sent by the source chain application layer and finally delivered
 
 The intermediary of cross-chain data is responsible for fetching data from one blockchain and then sending the data to the other side.
 
-## Channel
+## Channel & Lane
 
-Channels facilitate the transfer of data in one direction. A channel consists of a sender `outbound` of the source chain and a receiver `inbound` of the destination chain. Any user or system that wants to send a message on the bridge must submit it to the channel. The message layer supports multiple channels and provides different deliverability guarantees for messages, such as message replay protection, message order or out-of-order guarantee, etc.
+Channels facilitate the transfer of data in one direction. A channel consists of a sender `outboundLane` of the source chain and a receiver `inboundLane` of the target chain. Any user or system that wants to send a message on the bridge must submit it to the `outboundLane`. The message layer supports multiple channels and provides different deliverability guarantees for messages, such as message replay protection, message order or out-of-order guarantee, etc.
 
-Messages sent over the channel are assigned a unique (for this channel) strictly increasing integer value of the nonce. Messages sent over the same channel are guaranteed to be sent to the destination chain in the same order they were sent from the source chain. In other words, messages with nonce `N` will be delivered before nonce `N+1`.
+Messages sent over the channel are assigned a unique (for this channel) strictly increasing integer value of the nonce. Messages sent over the same channel are guaranteed to be sent to the target chain in the same order they were sent from the source chain. In other words, messages with nonce `N` will be delivered before nonce `N+1`.
 
 A single message channel can be thought of as a transport channel for a single application (on-chain, off-chain, or hybrid).
 
diff --git a/docs/sdk/api-reference.md b/docs/sdk/api-reference.md
index dd8ae657..ba407979 100644
--- a/docs/sdk/api-reference.md
+++ b/docs/sdk/api-reference.md
@@ -4,6 +4,23 @@ sidebar_position: 1
 
 # API Reference
 
+## _setRemoteEndpoint
+
+Set the remote endpoint.
+
+This is an internal function to be called by the concrete endpoint functions.
+
+```javascript
+function _setRemoteEndpoint(bytes4 _remoteChainId, address _remoteEndpoint)
+    internal
+```
+
+### Params:    
+
+* _remoteChainId: The remote chain id. [The full chain id list](../constants)
+
+* _remoteEndpoint: The remote endpoint contract address.
+
 ## _remoteDispatch
 
 Dispatch a substrate call of the target chain. 
diff --git a/docs/sdk/constants.md b/docs/sdk/constants.md
index 9c48ac74..45c7c0f1 100644
--- a/docs/sdk/constants.md
+++ b/docs/sdk/constants.md
@@ -4,9 +4,10 @@ sidebar_position: 6
 
 # Constants
 
-
 ## Chain Identifiers
 
+The chain identifier is used to uniquely identify the chain and is entered as a parameter when [setting the remote endpoint](./api-reference.md#_setRemoteEndpoint).
+
     bytes4 constant _DARWINIA_CHAIN_ID = 0x64617277; // darw
     bytes4 constant _CRAB_CHAIN_ID = 0x63726162; // crab
     bytes4 constant _PANGORO_CHAIN_ID = 0x70616772; // pagr
@@ -16,6 +17,8 @@ sidebar_position: 6
 
 ## Lane Identifiers
 
+The lane identifier identify the channel used to send and receive messages. Go to [Glossary](../glossary#channel--lane) to see more info. 
+
     bytes4 constant _DARWINIA_CRAB_LANE_ID = 0x00000000;
     bytes4 constant _PANGORO_PANGOLIN_LANE_ID = 0x726f6c69; // roli
     bytes4 constant _PANGOLIN_PANGOLIN_PARACHAIN_LANE_ID = 0x70616c69; // pali
diff --git a/docs/sdk/guides/04-call-smart-contract-remotely.md b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
similarity index 84%
rename from docs/sdk/guides/04-call-smart-contract-remotely.md
rename to docs/sdk/guides/03-execute-remote-smart-contract-call.md
index 4d10a1c9..461e1956 100644
--- a/docs/sdk/guides/04-call-smart-contract-remotely.md
+++ b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
@@ -1,11 +1,13 @@
 ---
-sidebar_position: 4
+sidebar_position: 3
 ---
 
-# Call Smart Contract Remotely
+# Execute Remote Smart Contract Call
 
 This Dapp allows you to call Pangolin Smart Chain's `add(2)` function from Pangoro.
 
+Pangoro is the canary network of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the canary network of Crab Network. 
+
 ## Install deps
 
 `npm install --save-dev @darwinia/contracts-periphery @darwinia/contracts-utils`
@@ -78,11 +80,11 @@ contract ExecuteDemo {
 
 Deploy it on the Pangoro Smart Chain. 
 
-Make sure that the endpoint are correct, it must be the ToPangolinEndpoint's address.
+Make sure that the endpoint is correct, it must be the ToPangolinEndpoint's address.
 
 Make sure that the latest spec version of pangolin is correct. You can get it from https://pangolin.subscan.io/runtime.
 
 ## Run
 
-1. You can get a estimated fee by calling the `fee` function of the ToPangolinEndpoint contract.
+1. You can get a estimated fee by calling [the `fee` function](../api-reference) of the ToPangolinEndpoint contract.
 2. Call the `remoteAdd(callee)` with a value. The value should greater than or equal to the estimated fee.
\ No newline at end of file
diff --git a/docs/sdk/guides/03-build-your-first-cross-chain-dapp.md b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
similarity index 81%
rename from docs/sdk/guides/03-build-your-first-cross-chain-dapp.md
rename to docs/sdk/guides/04-dispatch-remote-substrate-call.md
index 7e0956e0..58496c8c 100644
--- a/docs/sdk/guides/03-build-your-first-cross-chain-dapp.md
+++ b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
@@ -1,10 +1,14 @@
 ---
-sidebar_position: 3
+sidebar_position: 4
 ---
 
-# Build Your First Cross-chain Dapp
+# Dispatch Remote Substrate Call
 
-This Dapp allows you to call Pangolin's `remark_with_event` cross-chain from Pangoro.
+This guide helps you to build a small Dapp that will dispatch Pangolin's `remark_with_event` remotely from Pangoro.
+
+`remark_with_event` is a dispatchable call of the target Substrate based blockchain. A dispatchable call is a public function that can be executed at runtime via a JSON RPC call. More info about [Substrate](https://substrate.io/) and the [dispatchable calls](https://docs.substrate.io/reference/glossary/#dispatch).
+
+Pangoro is the canary network of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the canary network of Crab Network. 
 
 ## Install deps
 
@@ -115,17 +119,5 @@ Deploy the Dapp contract on the Pangoro Smart Chain. Inject the endpoint address
 
 ## Run
 
-1. You can get a estimated fee by calling the `fee` function of the endpoint contract.
+1. You can get a estimated fee by calling [the `fee` function](../api-reference) of the endpoint contract.
 2. Call the `remoteRemark` with a value. The value should greater than or equal to the estimated fee.
-
-## Track cross-chain events with subscan
-
-### MessageAccepted events of Pangoro
-
-[https://pangoro.subscan.io/event?address=&module=bridgedarwiniamessages&event=all](https://crab.subscan.io/event?address=&module=bridgedarwiniamessages&event=all)
-
-### MessageDispatched events of Pangolin
-
-[https://pangolin.subscan.io/event?address=&module=bridgecrabmessages&event=all](https://darwinia.subscan.io/event?address=&module=bridgecrabmessages&event=all)
-
-[More](./02-know-your-cross-chain-status.md)

From b83300ff70e9cb1c34e0ef8fc52cf31239776163 Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Thu, 21 Jul 2022 17:12:52 +0800
Subject: [PATCH 04/13] Fix

---
 docs/sdk/guides/03-execute-remote-smart-contract-call.md | 2 +-
 docs/sdk/guides/04-dispatch-remote-substrate-call.md     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/sdk/guides/03-execute-remote-smart-contract-call.md b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
index 461e1956..f83d2ca3 100644
--- a/docs/sdk/guides/03-execute-remote-smart-contract-call.md
+++ b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
@@ -87,4 +87,4 @@ Make sure that the latest spec version of pangolin is correct. You can get it fr
 ## Run
 
 1. You can get a estimated fee by calling [the `fee` function](../api-reference) of the ToPangolinEndpoint contract.
-2. Call the `remoteAdd(callee)` with a value. The value should greater than or equal to the estimated fee.
\ No newline at end of file
+2. Call the `remoteAdd(callee)` with a value as the market fee. The value should greater than or equal to the estimated fee.
\ No newline at end of file
diff --git a/docs/sdk/guides/04-dispatch-remote-substrate-call.md b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
index 58496c8c..610a8f4f 100644
--- a/docs/sdk/guides/04-dispatch-remote-substrate-call.md
+++ b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
@@ -120,4 +120,4 @@ Deploy the Dapp contract on the Pangoro Smart Chain. Inject the endpoint address
 ## Run
 
 1. You can get a estimated fee by calling [the `fee` function](../api-reference) of the endpoint contract.
-2. Call the `remoteRemark` with a value. The value should greater than or equal to the estimated fee.
+2. Call the `remoteRemark(_remark)` with a value as the market fee. The value should greater than or equal to the estimated fee.

From 5e1da68bb1c308913173dc3268043f02647351dd Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Thu, 21 Jul 2022 17:16:39 +0800
Subject: [PATCH 05/13] Fix ci

---
 docs/sdk/api-reference.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sdk/api-reference.md b/docs/sdk/api-reference.md
index ba407979..bf16d115 100644
--- a/docs/sdk/api-reference.md
+++ b/docs/sdk/api-reference.md
@@ -17,7 +17,7 @@ function _setRemoteEndpoint(bytes4 _remoteChainId, address _remoteEndpoint)
 
 ### Params:    
 
-* _remoteChainId: The remote chain id. [The full chain id list](../constants)
+* _remoteChainId: The remote chain id. [The full chain id list](./constants)
 
 * _remoteEndpoint: The remote endpoint contract address.
 

From 964866ac7ddbae377efa50662bb4feefb5a71d13 Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Thu, 21 Jul 2022 17:24:55 +0800
Subject: [PATCH 06/13] Minor style update

---
 src/css/custom.css | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/css/custom.css b/src/css/custom.css
index f72e2077..b1d62d36 100644
--- a/src/css/custom.css
+++ b/src/css/custom.css
@@ -50,7 +50,7 @@ html[data-theme='dark'] {
 }
 
 article {
-  max-width: 700px;
+  max-width: 95%;
   margin-left: auto;
   margin-right: auto;
 }

From 33bcfddb525366fb864ee26ab2e27d409de8ad29 Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Thu, 21 Jul 2022 22:10:03 +0800
Subject: [PATCH 07/13] Fix network name

---
 docs/sdk/guides/03-execute-remote-smart-contract-call.md | 2 +-
 docs/sdk/guides/04-dispatch-remote-substrate-call.md     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/sdk/guides/03-execute-remote-smart-contract-call.md b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
index f83d2ca3..0b0c265c 100644
--- a/docs/sdk/guides/03-execute-remote-smart-contract-call.md
+++ b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
@@ -6,7 +6,7 @@ sidebar_position: 3
 
 This Dapp allows you to call Pangolin Smart Chain's `add(2)` function from Pangoro.
 
-Pangoro is the canary network of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the canary network of Crab Network. 
+Pangoro is the testnet of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Network. 
 
 ## Install deps
 
diff --git a/docs/sdk/guides/04-dispatch-remote-substrate-call.md b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
index 610a8f4f..14972c0f 100644
--- a/docs/sdk/guides/04-dispatch-remote-substrate-call.md
+++ b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
@@ -8,7 +8,7 @@ This guide helps you to build a small Dapp that will dispatch Pangolin's `remark
 
 `remark_with_event` is a dispatchable call of the target Substrate based blockchain. A dispatchable call is a public function that can be executed at runtime via a JSON RPC call. More info about [Substrate](https://substrate.io/) and the [dispatchable calls](https://docs.substrate.io/reference/glossary/#dispatch).
 
-Pangoro is the canary network of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the canary network of Crab Network. 
+Pangoro is the testnet of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Network. 
 
 ## Install deps
 

From c4e0ac0bfa1b65571b3435e63f0c587e5638c733 Mon Sep 17 00:00:00 2001
From: Aki Wu <aki.wu@itering.com>
Date: Thu, 21 Jul 2022 22:12:46 +0800
Subject: [PATCH 08/13] Update
 docs/sdk/guides/04-dispatch-remote-substrate-call.md

Co-authored-by: bear <boundless.forest@outlook.com>
---
 docs/sdk/guides/04-dispatch-remote-substrate-call.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sdk/guides/04-dispatch-remote-substrate-call.md b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
index 14972c0f..4d4260ed 100644
--- a/docs/sdk/guides/04-dispatch-remote-substrate-call.md
+++ b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
@@ -119,5 +119,5 @@ Deploy the Dapp contract on the Pangoro Smart Chain. Inject the endpoint address
 
 ## Run
 
-1. You can get a estimated fee by calling [the `fee` function](../api-reference) of the endpoint contract.
+1. You can get a estimated fee by calling [the `fee` function](../api-reference/fee) of the endpoint contract.
 2. Call the `remoteRemark(_remark)` with a value as the market fee. The value should greater than or equal to the estimated fee.

From 39f00f21165a469d3380ffe2853be4c4ecf953c8 Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Thu, 21 Jul 2022 22:16:25 +0800
Subject: [PATCH 09/13] Fix fee link

---
 docs/sdk/guides/03-execute-remote-smart-contract-call.md | 2 +-
 docs/sdk/guides/04-dispatch-remote-substrate-call.md     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/sdk/guides/03-execute-remote-smart-contract-call.md b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
index 0b0c265c..3532222d 100644
--- a/docs/sdk/guides/03-execute-remote-smart-contract-call.md
+++ b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
@@ -86,5 +86,5 @@ Make sure that the latest spec version of pangolin is correct. You can get it fr
 
 ## Run
 
-1. You can get a estimated fee by calling [the `fee` function](../api-reference) of the ToPangolinEndpoint contract.
+1. You can get a estimated fee by calling [the `fee` function](../api-reference#fee) of the ToPangolinEndpoint contract.
 2. Call the `remoteAdd(callee)` with a value as the market fee. The value should greater than or equal to the estimated fee.
\ No newline at end of file
diff --git a/docs/sdk/guides/04-dispatch-remote-substrate-call.md b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
index 4d4260ed..9cea15dc 100644
--- a/docs/sdk/guides/04-dispatch-remote-substrate-call.md
+++ b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
@@ -119,5 +119,5 @@ Deploy the Dapp contract on the Pangoro Smart Chain. Inject the endpoint address
 
 ## Run
 
-1. You can get a estimated fee by calling [the `fee` function](../api-reference/fee) of the endpoint contract.
+1. You can get a estimated fee by calling [the `fee` function](../api-reference#fee) of the endpoint contract.
 2. Call the `remoteRemark(_remark)` with a value as the market fee. The value should greater than or equal to the estimated fee.

From d6643079240f36bba1626d96a94a19585b211f77 Mon Sep 17 00:00:00 2001
From: Aki Wu <aki.wu@itering.com>
Date: Fri, 22 Jul 2022 13:45:45 +0800
Subject: [PATCH 10/13] Update
 docs/sdk/guides/03-execute-remote-smart-contract-call.md

Co-authored-by: bear <boundless.forest@outlook.com>
---
 docs/sdk/guides/03-execute-remote-smart-contract-call.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sdk/guides/03-execute-remote-smart-contract-call.md b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
index 3532222d..dbe0af21 100644
--- a/docs/sdk/guides/03-execute-remote-smart-contract-call.md
+++ b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
@@ -6,7 +6,7 @@ sidebar_position: 3
 
 This Dapp allows you to call Pangolin Smart Chain's `add(2)` function from Pangoro.
 
-Pangoro is the testnet of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Network. 
+Pangoro is the testnet of Darwinia Network. [Pangolin Smart Chain](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Smart Chain. 
 
 ## Install deps
 

From 7bdb9a2827ffefe1e196fe30574f344c7d57c4bd Mon Sep 17 00:00:00 2001
From: wuminzhe <wuminzhe@gmail.com>
Date: Fri, 22 Jul 2022 13:51:53 +0800
Subject: [PATCH 11/13] Fix

---
 .../guides/03-execute-remote-smart-contract-call.md    | 10 ++++++----
 docs/sdk/guides/04-dispatch-remote-substrate-call.md   |  8 +++++---
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/docs/sdk/guides/03-execute-remote-smart-contract-call.md b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
index dbe0af21..e275974a 100644
--- a/docs/sdk/guides/03-execute-remote-smart-contract-call.md
+++ b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
@@ -4,17 +4,19 @@ sidebar_position: 3
 
 # Execute Remote Smart Contract Call
 
-This Dapp allows you to call Pangolin Smart Chain's `add(2)` function from Pangoro.
+This Dapp allows you to call Pangolin Smart Chain's `add(2)` function from Pangoro Smart Chain.
 
-Pangoro is the testnet of Darwinia Network. [Pangolin Smart Chain](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Smart Chain. 
+Pangoro Smart Chain is the testnet of Darwinia Smart Chain. [Pangolin Smart Chain](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Smart Chain. 
 
 ## Install deps
 
-`npm install --save-dev @darwinia/contracts-periphery @darwinia/contracts-utils`
+```bash
+npm install --save-dev @darwinia/contracts-periphery @darwinia/contracts-utils
+```
 
 ## Prepare your cross-chain endpoints
 
-We need two endpoints here. One is for Pangoro, and the another one is for Pangolin. We can download them here.
+We need two endpoints here. One is for Pangoro Smart Chain, and the another one is for Pangolin Smart Chain. We can download them here.
 
 1. Download [ToPangolinEndpoint.sol](https://raw.githubusercontent.com/darwinia-network/darwinia-messages-sol/master/contracts/periphery/contracts/s2s/examples/ToPangolinEndpoint.sol) for Pangoro. Then deploy it to Pangoro Smart Chain.
 
diff --git a/docs/sdk/guides/04-dispatch-remote-substrate-call.md b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
index 9cea15dc..45fa49b9 100644
--- a/docs/sdk/guides/04-dispatch-remote-substrate-call.md
+++ b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
@@ -4,15 +4,17 @@ sidebar_position: 4
 
 # Dispatch Remote Substrate Call
 
-This guide helps you to build a small Dapp that will dispatch Pangolin's `remark_with_event` remotely from Pangoro.
+This guide helps you to build a small Dapp that will dispatch Pangolin's `remark_with_event` remotely from Pangoro Smart Chain.
 
 `remark_with_event` is a dispatchable call of the target Substrate based blockchain. A dispatchable call is a public function that can be executed at runtime via a JSON RPC call. More info about [Substrate](https://substrate.io/) and the [dispatchable calls](https://docs.substrate.io/reference/glossary/#dispatch).
 
-Pangoro is the testnet of Darwinia Network. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Network. 
+Pangoro Smart Chain is the testnet of Darwinia Smart Chain. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Network. 
 
 ## Install deps
 
-`npm install --save-dev @darwinia/contracts-periphery @darwinia/contracts-utils`
+```bash
+npm install --save-dev @darwinia/contracts-periphery @darwinia/contracts-utils
+```
 
 ## Prepare your cross-chain endpoint
 

From 2b29733f4cf161ed19d2069aa3d1dba1d2e2a751 Mon Sep 17 00:00:00 2001
From: Aki Wu <aki.wu@itering.com>
Date: Fri, 22 Jul 2022 14:23:17 +0800
Subject: [PATCH 12/13] Update
 docs/sdk/guides/03-execute-remote-smart-contract-call.md

Co-authored-by: bear <boundless.forest@outlook.com>
---
 docs/sdk/guides/03-execute-remote-smart-contract-call.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sdk/guides/03-execute-remote-smart-contract-call.md b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
index e275974a..4f747589 100644
--- a/docs/sdk/guides/03-execute-remote-smart-contract-call.md
+++ b/docs/sdk/guides/03-execute-remote-smart-contract-call.md
@@ -24,7 +24,7 @@ We need two endpoints here. One is for Pangoro Smart Chain, and the another one
 
 3. Call the `setRemoteEndpoint(_remoteChainId, _remoteEndpoint)` of the two endpoints to point to each other. 
 
-The chain id of Pangoro is `0x70616772`. The chain id of `Pangolin` is 0x7061676c.  
+The chain id of Pangoro Smart Chain is `0x70616772`. The chain id of Pangolin Smart Chain is `0x7061676c`.  
 
 You can get the full chain id list from [constants](../constants).
 

From f664b4162b6c361337ff257f790d9aff17d83186 Mon Sep 17 00:00:00 2001
From: Aki Wu <aki.wu@itering.com>
Date: Fri, 22 Jul 2022 14:23:28 +0800
Subject: [PATCH 13/13] Update
 docs/sdk/guides/04-dispatch-remote-substrate-call.md

Co-authored-by: bear <boundless.forest@outlook.com>
---
 docs/sdk/guides/04-dispatch-remote-substrate-call.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sdk/guides/04-dispatch-remote-substrate-call.md b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
index 45fa49b9..c017fb41 100644
--- a/docs/sdk/guides/04-dispatch-remote-substrate-call.md
+++ b/docs/sdk/guides/04-dispatch-remote-substrate-call.md
@@ -8,7 +8,7 @@ This guide helps you to build a small Dapp that will dispatch Pangolin's `remark
 
 `remark_with_event` is a dispatchable call of the target Substrate based blockchain. A dispatchable call is a public function that can be executed at runtime via a JSON RPC call. More info about [Substrate](https://substrate.io/) and the [dispatchable calls](https://docs.substrate.io/reference/glossary/#dispatch).
 
-Pangoro Smart Chain is the testnet of Darwinia Smart Chain. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Network. 
+Pangoro Smart Chain is the testnet of Darwinia Smart Chain. [Pangolin](https://docs.crab.network/evm-compatible-crab-smart-chain/get-started/darwinia-pangolin) is the testnet of Crab Chain. 
 
 ## Install deps