import { exec } from "@actions/exec";
import * as io from "@actions/io";
import { existsSync, writeFileSync } from "fs";
import * as path from "path";

import { CompressionMethod } from "./constants";
import * as utils from "./utils/actionUtils";

async function getTarPath(args: string[]): Promise<string> {
    // Explicitly use BSD Tar on Windows
    const IS_WINDOWS = process.platform === "win32";
    if (IS_WINDOWS) {
        const systemTar = `${process.env["windir"]}\\System32\\tar.exe`;
        if (existsSync(systemTar)) {
            return systemTar;
        } else if (await utils.useGnuTar()) {
            args.push("--force-local");
        }
    }
    return await io.which("tar", true);
}

async function execTar(args: string[], cwd?: string): Promise<void> {
    try {
        await exec(`"${await getTarPath(args)}"`, args, { cwd: cwd });
    } catch (error) {
        throw new Error(`Tar failed with error: ${error?.message}`);
    }
}

function getWorkingDirectory(): string {
    return process.env["GITHUB_WORKSPACE"] ?? process.cwd();
}

export async function extractTar(
    archivePath: string,
    compressionMethod: CompressionMethod
): Promise<void> {
    // Create directory to extract tar into
    const workingDirectory = getWorkingDirectory();
    await io.mkdirP(workingDirectory);
    // --d: Decompress.
    // --long=#: Enables long distance matching with # bits. Maximum is 30 (1GB) on 32-bit OS and 31 (2GB) on 64-bit.
    // Using 30 here because we also support 32-bit self-hosted runners.
    const args = [
        ...(compressionMethod == CompressionMethod.Zstd
            ? ["--use-compress-program", "zstd -d --long=30"]
            : ["-z"]),
        "-xf",
        archivePath.replace(new RegExp("\\" + path.sep, "g"), "/"),
        "-P",
        "-C",
        workingDirectory.replace(new RegExp("\\" + path.sep, "g"), "/")
    ];
    await execTar(args);
}

export async function createTar(
    archiveFolder: string,
    sourceDirectories: string[],
    compressionMethod: CompressionMethod
): Promise<void> {
    // Write source directories to manifest.txt to avoid command length limits
    const manifestFilename = "manifest.txt";
    const cacheFileName = utils.getCacheFileName(compressionMethod);
    writeFileSync(
        path.join(archiveFolder, manifestFilename),
        sourceDirectories.join("\n")
    );
    // -T#: Compress using # working thread. If # is 0, attempt to detect and use the number of physical CPU cores.
    // --long=#: Enables long distance matching with # bits. Maximum is 30 (1GB) on 32-bit OS and 31 (2GB) on 64-bit.
    // Using 30 here because we also support 32-bit self-hosted runners.
    const workingDirectory = getWorkingDirectory();
    const args = [
        ...(compressionMethod == CompressionMethod.Zstd
            ? ["--use-compress-program", "zstd -T0 --long=30"]
            : ["-z"]),
        "-cf",
        cacheFileName.replace(new RegExp("\\" + path.sep, "g"), "/"),
        "-P",
        "-C",
        workingDirectory.replace(new RegExp("\\" + path.sep, "g"), "/"),
        "--files-from",
        manifestFilename
    ];
    await execTar(args, archiveFolder);
}