'use strict';

import BN from 'bn.js';
import { Account } from './account';
import { getTransactionLastResult } from './providers';
import { PositionalArgsError, ArgumentTypeError } from './utils/errors';

export class Contract {
    readonly account: Account;
    readonly contractId: string;

    constructor(account: Account, contractId: string, options: { viewMethods: string[], changeMethods: string[] }) {
        this.account = account;
        this.contractId = contractId;
        const { viewMethods = [], changeMethods = [] } = options;
        viewMethods.forEach((methodName) => {
            Object.defineProperty(this, methodName, {
                writable: false,
                enumerable: true,
                value: async function(args: any) {
                    if (arguments.length > 1) {
                        throw new PositionalArgsError();
                    }
                    return this.account.viewFunction(this.contractId, methodName, args || {});
                }
            });
        });
        changeMethods.forEach((methodName) => {
            Object.defineProperty(this, methodName, {
                writable: false,
                enumerable: true,
                value: async function(args: any, gas?: BN, amount?: BN) {
                    if (arguments.length > 3) {
                        throw new PositionalArgsError();
                    }
                    validateBNLike({ gas, amount });
                    const rawResult = await this.account.functionCall(this.contractId, methodName, args || {}, gas, amount);
                    return getTransactionLastResult(rawResult);
                }
            });
        });
    }
}

function validateBNLike(argMap: { [name: string]: any }) {
    const bnLike = 'number, decimal string or BN';
    for (const argName of Object.keys(argMap)) {
        const argValue = argMap[argName];
        if (argValue && !BN.isBN(argValue) && isNaN(argValue)) {
            throw new ArgumentTypeError(argName, bnLike, argValue);
        }
    }
}