"use strict";

// See: https://github.com/ethereum/wiki/wiki/JSON-RPC

import { Provider, TransactionRequest, TransactionResponse } from "@ethersproject/abstract-provider";
import { Signer } from "@ethersproject/abstract-signer";
import { BigNumber } from "@ethersproject/bignumber";
import { Bytes, hexlify, hexValue } from "@ethersproject/bytes";
import * as errors from "@ethersproject/errors";
import { getNetwork, Network, Networkish } from "@ethersproject/networks";
import { checkProperties, deepCopy, defineReadOnly, resolveProperties, shallowCopy } from "@ethersproject/properties";
import { toUtf8Bytes } from "@ethersproject/strings";
import { ConnectionInfo, fetchJson, poll } from "@ethersproject/web";

import { BaseProvider } from "./base-provider";


function timer(timeout: number): Promise<any> {
    return new Promise(function(resolve) {
        setTimeout(function() {
            resolve();
        }, timeout);
    });
}

function getResult(payload: { error?: { code?: number, data?: any, message?: string }, result?: any }): any {
    if (payload.error) {
        // @TODO: not any
        let error: any = new Error(payload.error.message);
        error.code = payload.error.code;
        error.data = payload.error.data;
        throw error;
    }

    return payload.result;
}

function getLowerCase(value: string): string {
    if (value) { return value.toLowerCase(); }
    return value;
}

const _constructorGuard = {};

export class JsonRpcSigner extends Signer {
    readonly provider: JsonRpcProvider;
    _index: number;
    _address: string;

    constructor(constructorGuard: any, provider: JsonRpcProvider, addressOrIndex?: string | number) {
        errors.checkNew(new.target, JsonRpcSigner);

        super();

        if (constructorGuard !== _constructorGuard) {
            throw new Error("do not call the JsonRpcSigner constructor directly; use provider.getSigner");
        }

        defineReadOnly(this, "provider", provider);

        if (addressOrIndex == null) { addressOrIndex = 0; }

        if (typeof(addressOrIndex) === "string") {
            defineReadOnly(this, "_address", this.provider.formatter.address(addressOrIndex));
            defineReadOnly(this, "_index", null);

        } else if (typeof(addressOrIndex) === "number") {
            defineReadOnly(this, "_index", addressOrIndex);
            defineReadOnly(this, "_address", null);

        } else {
            errors.throwError("invalid address or index", errors.INVALID_ARGUMENT, { argument: "addressOrIndex", value: addressOrIndex });
        }
    }

    connect(provider: Provider): JsonRpcSigner {
        return errors.throwError("cannot alter JSON-RPC Signer connection", errors.UNSUPPORTED_OPERATION, {
            operation: "connect"
        });
    }

    connectUnchecked(): JsonRpcSigner {
        return new UncheckedJsonRpcSigner(_constructorGuard, this.provider, this._address || this._index);
    }

    getAddress(): Promise<string> {
        if (this._address) {
            return Promise.resolve(this._address);
        }

        return this.provider.send("eth_accounts", []).then((accounts) => {
            if (accounts.length <= this._index) {
                errors.throwError("unknown account #" + this._index, errors.UNSUPPORTED_OPERATION, { operation: "getAddress" });
            }
            return this.provider.formatter.address(accounts[this._index])
        });
    }

    sendUncheckedTransaction(transaction: TransactionRequest): Promise<string> {
        transaction = shallowCopy(transaction);

        let fromAddress = this.getAddress().then((address) => {
            if (address) { address = address.toLowerCase(); }
            return address;
        });

        // The JSON-RPC for eth_sendTransaction uses 90000 gas; if the user
        // wishes to use this, it is easy to specify explicitly, otherwise
        // we look it up for them.
        if (transaction.gasLimit == null) {
            let estimate = shallowCopy(transaction);
            estimate.from = fromAddress;
            transaction.gasLimit = this.provider.estimateGas(estimate);
        }

        return Promise.all([
            resolveProperties(transaction),
            fromAddress
        ]).then((results) => {
            let tx = results[0];
            let hexTx = (<any>this.provider.constructor).hexlifyTransaction(tx);
            hexTx.from = results[1];
            return this.provider.send("eth_sendTransaction", [ hexTx ]).then((hash) => {
                return hash;
            }, (error) => {
                if (error.responseText) {
                    // See: JsonRpcProvider.sendTransaction (@TODO: Expose a ._throwError??)
                    if (error.responseText.indexOf("insufficient funds") >= 0) {
                        errors.throwError("insufficient funds", errors.INSUFFICIENT_FUNDS, {
                            transaction: tx
                        });
                    }
                    if (error.responseText.indexOf("nonce too low") >= 0) {
                        errors.throwError("nonce has already been used", errors.NONCE_EXPIRED, {
                            transaction: tx
                        });
                    }
                    if (error.responseText.indexOf("replacement transaction underpriced") >= 0) {
                        errors.throwError("replacement fee too low", errors.REPLACEMENT_UNDERPRICED, {
                            transaction: tx
                        });
                    }
                }
                throw error;
            });
        });
    }

    signTransaction(transaction: TransactionRequest): Promise<string> {
        return errors.throwError("signing transactions is unsupported", errors.UNSUPPORTED_OPERATION, {
            operation: "signTransaction"
        });
    }

    sendTransaction(transaction: TransactionRequest): Promise<TransactionResponse> {
        return this.sendUncheckedTransaction(transaction).then((hash) => {
            return poll(() => {
                return this.provider.getTransaction(hash).then((tx: TransactionResponse) => {
                    if (tx === null) { return undefined; }
                    return this.provider._wrapTransaction(tx, hash);
                });
            }, { onceBlock: this.provider }).catch((error: Error) => {
                (<any>error).transactionHash = hash;
                throw error;
            });
        });
    }

    signMessage(message: Bytes | string): Promise<string> {
        let data = ((typeof(message) === "string") ? toUtf8Bytes(message): message);
        return this.getAddress().then((address) => {

            // https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign
            return this.provider.send("eth_sign", [ address.toLowerCase(), hexlify(data) ]);
        });
    }

    unlock(password: string): Promise<boolean> {
        let provider = this.provider;

        return this.getAddress().then(function(address) {
            return provider.send("personal_unlockAccount", [ address.toLowerCase(), password, null ]);
        });
    }
}

class UncheckedJsonRpcSigner extends JsonRpcSigner {
    sendTransaction(transaction: TransactionRequest): Promise<TransactionResponse> {
        return this.sendUncheckedTransaction(transaction).then((hash) => {
            return <TransactionResponse>{
                hash: hash,
                nonce: null,
                gasLimit: null,
                gasPrice: null,
                data: null,
                value: null,
                chainId: null,
                confirmations: 0,
                from: null,
                wait: (confirmations?: number) => { return this.provider.waitForTransaction(hash, confirmations); }
            };
        });
    }
}

const allowedTransactionKeys: { [ key: string ]: boolean } = {
    chainId: true, data: true, gasLimit: true, gasPrice:true, nonce: true, to: true, value: true
}

export class JsonRpcProvider extends BaseProvider {
    readonly connection: ConnectionInfo;

    _pendingFilter: Promise<number>;
    _nextId: number;

    constructor(url?: ConnectionInfo | string, network?: Networkish) {
        errors.checkNew(new.target, JsonRpcProvider);

        // One parameter, but it is a network name, so swap it with the URL
        if (typeof(url) === "string") {
            if (network === null && getNetwork(url)) {
                network = url;
                url = null;
            }
        }

        if (network) {
            // The network has been specified explicitly, we can use it
            super(network);

        } else {

            // The network is unknown, query the JSON-RPC for it
            let ready: Promise<Network> = new Promise((resolve, reject) => {
                setTimeout(() => {
                    this.send("eth_chainId", [ ]).then((result) => {
                        resolve(getNetwork(BigNumber.from(result).toNumber()));
                    }).catch((error) => {
                        this.send("net_version", [ ]).then((result) => {
                            resolve(getNetwork(BigNumber.from(result).toNumber()));
                        }).catch((error) => {
                            reject(errors.makeError("could not detect network", errors.NETWORK_ERROR, { })); 
                        });
                    });
                });
            });
            super(ready);
        }

        // Default URL
        if (!url) { url = "http:/" + "/localhost:8545"; }

        if (typeof(url) === "string") {
            this.connection = {
                url: url
            };
        } else {
            this.connection = url;
        }

        this._nextId = 42;
    }

    getSigner(addressOrIndex?: string | number): JsonRpcSigner {
        return new JsonRpcSigner(_constructorGuard, this, addressOrIndex);
    }

    getUncheckedSigner(addressOrIndex?: string | number): UncheckedJsonRpcSigner {
        return this.getSigner(addressOrIndex).connectUnchecked();
    }

    listAccounts(): Promise<Array<string>> {
        return this.send("eth_accounts", []).then((accounts: Array<string>) => {
            return accounts.map((a) => this.formatter.address(a));
        });
    }

    send(method: string, params: any): Promise<any> {
        let request = {
            method: method,
            params: params,
            id: (this._nextId++),
            jsonrpc: "2.0"
        };

        this.emit("debug", {
            action: "request",
            request: deepCopy(request),
            provider: this
        });

        return fetchJson(this.connection, JSON.stringify(request), getResult).then((result) => {
            this.emit("debug", {
                action: "response",
                request: request,
                response: result,
                provider: this
            });
            return result;
        });
    }

    perform(method: string, params: any): Promise<any> {
        switch (method) {
            case "getBlockNumber":
                return this.send("eth_blockNumber", []);

            case "getGasPrice":
                return this.send("eth_gasPrice", []);

            case "getBalance":
                return this.send("eth_getBalance", [ getLowerCase(params.address), params.blockTag ]);

            case "getTransactionCount":
                return this.send("eth_getTransactionCount", [ getLowerCase(params.address), params.blockTag ]);

            case "getCode":
                return this.send("eth_getCode", [ getLowerCase(params.address), params.blockTag ]);

            case "getStorageAt":
                return this.send("eth_getStorageAt", [ getLowerCase(params.address), params.position, params.blockTag ]);

            case "sendTransaction":
                return this.send("eth_sendRawTransaction", [ params.signedTransaction ]).catch((error) => {
                    if (error.responseText) {
                        // "insufficient funds for gas * price + value"
                        if (error.responseText.indexOf("insufficient funds") > 0) {
                            errors.throwError("insufficient funds", errors.INSUFFICIENT_FUNDS, { });
                        }
                        // "nonce too low"
                        if (error.responseText.indexOf("nonce too low") > 0) {
                            errors.throwError("nonce has already been used", errors.NONCE_EXPIRED, { });
                        }
                        // "replacement transaction underpriced"
                        if (error.responseText.indexOf("replacement transaction underpriced") > 0) {
                            errors.throwError("replacement fee too low", errors.REPLACEMENT_UNDERPRICED, { });
                        }
                    }
                    throw error;
                });

            case "getBlock":
                if (params.blockTag) {
                    return this.send("eth_getBlockByNumber", [ params.blockTag, !!params.includeTransactions ]);
                } else if (params.blockHash) {
                    return this.send("eth_getBlockByHash", [ params.blockHash, !!params.includeTransactions ]);
                }
                return Promise.reject(new Error("invalid block tag or block hash"));

            case "getTransaction":
                return this.send("eth_getTransactionByHash", [ params.transactionHash ]);

            case "getTransactionReceipt":
                return this.send("eth_getTransactionReceipt", [ params.transactionHash ]);

            case "call":
                return this.send("eth_call", [ (<any>this.constructor).hexlifyTransaction(params.transaction, { from: true }), params.blockTag ]);

            case "estimateGas":
                return this.send("eth_estimateGas", [ (<any>this.constructor).hexlifyTransaction(params.transaction, { from: true }) ]);

            case "getLogs":
                if (params.filter && params.filter.address != null) {
                    params.filter.address = getLowerCase(params.filter.address);
                }
                return this.send("eth_getLogs", [ params.filter ]);

            default:
                break;
        }

        return errors.throwError(method + " not implemented", errors.NOT_IMPLEMENTED, { operation: method });
    }

    _startPending(): void {
        if (this._pendingFilter != null) { return; }
        let self = this;

        let pendingFilter: Promise<number> = this.send("eth_newPendingTransactionFilter", []);
        this._pendingFilter = pendingFilter;

        pendingFilter.then(function(filterId) {
            function poll() {
                self.send("eth_getFilterChanges", [ filterId ]).then(function(hashes: Array<string>) {
                    if (self._pendingFilter != pendingFilter) { return null; }

                    let seq = Promise.resolve();
                    hashes.forEach(function(hash) {
                        // @TODO: This should be garbage collected at some point... How? When?
                        self._emitted["t:" + hash.toLowerCase()] = "pending";
                        seq = seq.then(function() {
                            return self.getTransaction(hash).then(function(tx) {
                                self.emit("pending", tx);
                                return null;
                            });
                        });
                    });

                    return seq.then(function() {
                        return timer(1000);
                    });
                }).then(function() {
                    if (self._pendingFilter != pendingFilter) {
                        self.send("eth_uninstallFilter", [ filterId ]);
                        return;
                    }
                    setTimeout(function() { poll(); }, 0);

                    return null;
                }).catch((error: Error) => { });
            }
            poll();

            return filterId;
        }).catch((error: Error) => { });
    }

    _stopPending(): void {
        this._pendingFilter = null;
    }

    // Convert an ethers.js transaction into a JSON-RPC transaction
    //  - gasLimit => gas
    //  - All values hexlified
    //  - All numeric values zero-striped
    // NOTE: This allows a TransactionRequest, but all values should be resolved
    //       before this is called
    static hexlifyTransaction(transaction: TransactionRequest, allowExtra?: { [key: string]: boolean }): { [key: string]: string } {
        // Check only allowed properties are given
        let allowed = shallowCopy(allowedTransactionKeys);
        if (allowExtra) {
            for (let key in allowExtra) {
                if (allowExtra[key]) { allowed[key] = true; }
            }
        }
        checkProperties(transaction, allowed);

        let result: { [key: string]: string } = {};

        // Some nodes (INFURA ropsten; INFURA mainnet is fine) do not like leading zeros.
        ["gasLimit", "gasPrice", "nonce", "value"].forEach(function(key) {
            if ((<any>transaction)[key] == null) { return; }
            let value = hexValue((<any>transaction)[key]);
            if (key === "gasLimit") { key = "gas"; }
            result[key] = value;
        });

        ["from", "to", "data"].forEach(function(key) {
            if ((<any>transaction)[key] == null) { return; }
            result[key] = hexlify((<any>transaction)[key]);
        });

        return result;
    }
}