import * as _ from 'lodash';

import { constants } from './constants';
import { getTracesByContractAddress } from './trace';
import { TraceCollectionSubprovider } from './trace_collection_subprovider';
import { TraceInfo, TraceInfoExistingContract, TraceInfoNewContract } from './types';

// TraceInfoSubprovider is extended by subproviders which need to work with one
// TraceInfo at a time. It has one abstract method: _handleTraceInfoAsync, which
// is called for each TraceInfo.
export abstract class TraceInfoSubprovider extends TraceCollectionSubprovider {
    protected abstract _handleTraceInfoAsync(traceInfo: TraceInfo): Promise<void>;
    protected async _recordTxTraceAsync(address: string, data: string | undefined, txHash: string): Promise<void> {
        await this._web3Wrapper.awaitTransactionMinedAsync(txHash, 0);
        // For very large traces we use a custom tracer that outputs a format compatible with a
        // regular trace. We only need the 2nd item on the stack when the instruction is a call.
        // By not including othe stack values, we severly limit the amount of data to be collectd.
        const tracer = `
            {
                data: [],
                step: function(log) {
                    const op = log.op.toString();
                    const opn = 0 | log.op.toNumber();
                    const pc = 0 | log.getPC();
                    const depth = 0 | log.getDepth();
                    const gasCost = 0 | log.getCost();
                    const gas = 0 | log.getGas();
                    const isCall = opn == 0xf1 || opn == 0xf2 || opn == 0xf4 || opn == 0xf5;
                    const stack = isCall ? ['0x'+log.stack.peek(1).toString(16), null] : null;
                    this.data.push({ pc, gasCost, depth, op, stack, gas });
                },
                fault: function() { },
                result: function() { return {structLogs: this.data}; }
            }
        `;
        const trace = await this._web3Wrapper.getTransactionTraceAsync(txHash, { tracer, timeout: '600s' });
        const tracesByContractAddress = getTracesByContractAddress(trace.structLogs, address);
        const subcallAddresses = _.keys(tracesByContractAddress);
        if (address === constants.NEW_CONTRACT) {
            for (const subcallAddress of subcallAddresses) {
                let traceInfo: TraceInfoNewContract | TraceInfoExistingContract;
                if (subcallAddress === 'NEW_CONTRACT') {
                    const traceForThatSubcall = tracesByContractAddress[subcallAddress];
                    traceInfo = {
                        subtrace: traceForThatSubcall,
                        txHash,
                        address: subcallAddress,
                        bytecode: data as string,
                    };
                } else {
                    const runtimeBytecode = await this._web3Wrapper.getContractCodeAsync(subcallAddress);
                    const traceForThatSubcall = tracesByContractAddress[subcallAddress];
                    traceInfo = {
                        subtrace: traceForThatSubcall,
                        txHash,
                        address: subcallAddress,
                        runtimeBytecode,
                    };
                }
                await this._handleTraceInfoAsync(traceInfo);
            }
        } else {
            for (const subcallAddress of subcallAddresses) {
                const runtimeBytecode = await this._web3Wrapper.getContractCodeAsync(subcallAddress);
                const traceForThatSubcall = tracesByContractAddress[subcallAddress];
                const traceInfo: TraceInfoExistingContract = {
                    subtrace: traceForThatSubcall,
                    txHash,
                    address: subcallAddress,
                    runtimeBytecode,
                };
                await this._handleTraceInfoAsync(traceInfo);
            }
        }
    }
}