import assert from 'assert';
import { ChildProcessByStdio, spawn } from 'child_process';
import * as fs from "fs";
import * as path from 'path';
import { createInterface } from 'readline';
import { Readable, Writable } from 'stream';
import { promisify } from "util";
import specTemplate from '../../assets/specTemplate.cfg';
import { RunCPUOptions, runcpuOptions } from '../commands/spec.js';
import { SPECBenchData, benchpath, buildpath, exepath } from './benchData.js';



export function getEnvironment(specdir: string): NodeJS.ProcessEnv {
    return {
        ...process.env,
        SPEC: specdir,
        PATH: `${path.join(specdir, 'bin')}${path.delimiter}${process.env.PATH}`,
    };
}

export interface SPEC {
    newConfig: (name: string, content: string) => Promise<void>;
    benchpath: (bench: SPECBenchData) => string;
    exepath: (bench: SPECBenchData) => string;
    buildpath: (bench: SPECBenchData) => string;
    getEnvironment: () => NodeJS.ProcessEnv;
}

export function mkSPEC(specRoot: string): SPEC {
    return {
        newConfig: async (name: string, content: string) => {
            await writeFile(path.join(specRoot, "config", name), content);
        },
        benchpath: bench => benchpath(specRoot, bench),
        exepath: bench => exepath(specRoot, bench),
        buildpath: bench => buildpath(specRoot, bench),
        getEnvironment: () => getEnvironment(specRoot),
    };
}

export interface Bench {
    benchpath: () => string;
    exepath: () => string;
    buildpath: () => string;
    benchData: () => SPECBenchData;
    spec: () => SPEC;
}


export function mkBench(spec: SPEC, bench: SPECBenchData): Bench {
    return {
        benchpath: () => spec.benchpath(bench),
        exepath: () => spec.exepath(bench),
        buildpath: () => spec.buildpath(bench),
        benchData: () => bench,
        spec: () => spec,
    };
}

const writeFile = promisify(fs.writeFile);

export interface ConfigOptions {
    optimize: string[];
    ldflags: string[];
    libs: string[];
    openmp: {
        threads: number;
    };
    compilerPaths: {
        CXX: string,
        CC: string,
        FC: string,
    };
    specialFlags: string,
}

// Pure function to render configuration
export const renderConfig = (options: ConfigOptions): string => {
    return `# Rendered from TypeScript ${new Date().toLocaleString()}, do not edit!\n\n\n` +
        specTemplate
            .replace("@@OPTIMIZE@@", options.optimize.join(" "))
            .replace("@@LDFLAGS@@", options.ldflags.join(" "))
            .replace("@@CompilerCC@@", options.compilerPaths.CC)
            .replace("@@CompilerCXX@@", options.compilerPaths.CXX)
            .replace("@@CompilerFC@@", options.compilerPaths.FC)
            .replace("@@LIBS@@", options.libs.join(" "))
            .replace("@@SpecialFlags@@", options.specialFlags)
            .replace("@@OpenMPThreads@@", options.openmp.threads.toString())
        ;
};

export interface SPECResult {
    outputFiles: { [key: string]: string[], };
}

/**
 * Monitor SPEC2017 runcpu process in a subprocess.
 */
export async function watchSPEC<T extends ChildProcessByStdio<null | Writable, Readable, Readable>>(process: T) {
    const rl = createInterface({
        input: process.stdout,
        terminal: false,
    });

    // Match & extract string like "  format CSV -> /path/to/csv"
    const formatRe = /^\s*format:\s*(\w+)\s*->\s*(.*)$/;

    return await new Promise<SPECResult>((resolve, reject) => {
        let outputFiles: { [key: string]: string[]; } = {};
        rl.on("line", line => {
            let match;
            if ((match = formatRe.exec(line)) != null) {
                const type = match[1];
                const paths = match[2].split(',').map(path => path.trim());
                outputFiles[type] = paths;
            }
            // To match if the line contains: "runcpu finished
            if (line.startsWith("runcpu finished")) {
                resolve({
                    outputFiles
                });
            }
        });
        process.on("error", error => reject(error));
        process.on("close", () => resolve({
            outputFiles
        }));
    });
}

export interface SPECResultsTable {
    baseThreads: string,
    baseRuntime: string,
    baseRatio: string,
    BaseSelected: string,
    baseStatus: string,
    peakThreads: string,
    peakRuntime: string,
    peakRatio: string,
    peakSelected: string,
    peakStatus: string,
    description?: string,
}

export const extract = (field: keyof SPECResultsTable) => (o: ParsedResult) => {
    return Object.fromEntries(Object
        .entries(o)
        .filter(([_, b]) => b[field] !== '' && b[field] !== undefined && b.baseStatus === 'S')
        .map(([a, b]) => [a, parseFloat(b[field]!)]));
};

export const extractBaseRatio = extract('baseRatio');

export const baseRatioFromPath = async (path: string) => {
    const result = parseSPECCSVResultsTable((await fs.promises.readFile(path)).toString());
    return extractBaseRatio(result);
};

export async function getBaseRatios<T extends ChildProcessByStdio<null | Writable, Readable, Readable>>(proc: T) {
    const specResultCSVs = (await watchSPEC(proc)).outputFiles["CSV"];
    assert(specResultCSVs !== undefined && specResultCSVs.length === 1);
    const specCSV = await fs.promises.readFile(specResultCSVs[0], "utf-8");
    return extractBaseRatio(parseSPECCSVResultsTable(specCSV));
}

export interface ParsedResult {
    [key: string]: SPECResultsTable;
}

export function parseSPECCSVResultsTable(data: string): ParsedResult {
    const lines = data.split("\n");
    let index = 0;
    const eof = () => index >= lines.length;

    let results: { [key: string]: SPECResultsTable; } = {};
    while (!eof()) {
        const line = lines[index];
        if (line.startsWith('"Full Results Table"')) {
            index += 3;
            // "Full Results Table"

            // Benchmark,"Base # Threads","Est. Base Run Time","Est. Base Ratio","Base Selected","Base Status","Peak # Threads","Est. Peak Run Time","Est. Peak Ratio","Peak Selected","Peak Status",Description
            // 600.perlbench_s,1,65.357247,--,0,VE,,,,,,"test iteration #1"
            // 602.gcc_s,,,,,NR,,,,,NR
            // 605.mcf_s,,,,,NR,,,,,NR
            // 620.omnetpp_s,,,,,NR,,,,,NR
            // 623.xalancbmk_s,,,,,NR,,,,,NR
            // 625.x264_s,,,,,NR,,,,,NR
            // 631.deepsjeng_s,,,,,NR,,,,,NR
            // 641.leela_s,,,,,NR,,,,,NR
            // 648.exchange2_s,,,,,NR,,,,,NR
            // 657.xz_s,,,,,NR,,,,,NR
            while (!eof()) {
                const dataLine = lines[index];
                if (dataLine.length == 0)
                    break;
                const fields: (keyof SPECResultsTable)[] = [
                    "baseThreads",
                    "baseRuntime",
                    "baseRatio",
                    "BaseSelected",
                    "baseStatus",
                    "peakThreads",
                    "peakRuntime",
                    "peakRatio",
                    "peakSelected",
                    "peakStatus",
                    "description",
                ];
                const splitted = dataLine.split(",");
                const entries: [keyof SPECResultsTable, string][] = splitted.slice(1).map((name, index) => [fields[index], name]);
                results[splitted[0]] = (Object.fromEntries(entries) as { [K in keyof SPECResultsTable]: string });
                index++;
            }
        }
        index++;
    }
    return results;
}


export async function spawnSPECWithID(
    spec: SPEC,
    specConfig: ConfigOptions,
    runcpuConfig: RunCPUOptions,
    outputPath: string,
    id: string,
) {
    const outputRoot = path.resolve(outputPath, id);

    console.log(`runspec: launch SPEC benchmark at ${id}, config: ${JSON.stringify(specConfig)}`);
    console.log(`runspec: view output dir: ${outputRoot}`);

    const config = `${id}.cfg`;

    await spec.newConfig(config, renderConfig(specConfig));

    return spawn('runcpu', runcpuOptions({
        outputRoot,
        config,
        ...runcpuConfig,
    }), { env: spec.getEnvironment() });
}