import { delimiter, resolve, normalize, join } from "path";
import { Buffer } from "buffer";
import { createReadStream, ReadStream } from "fs";
import { spawn } from "child_process";
import { Logger, LogStep } from "./logger";
import {
  readFileAsync,
  writeFileAsync,
  pathExistsAsync,
  statAsync,
  dequote,
  isWindows,
  bound,
  semverGt
} from "./util";
import { NexeOptions, version } from "./options";
import { NexeTarget } from "./target";
import { Readable, Transform } from "stream";
import MultiStream = require("multistream");
import { Bundle, toStream } from "./fs/bundle";
import { File } from "resolve-dependencies";

const isBsd = Boolean(~process.platform.indexOf("bsd"));
const make = isWindows ? "vcbuild.bat" : isBsd ? "gmake" : "make";
const configure = isWindows ? "configure" : "./configure";

type StringReplacer = (match: string) => string;

export interface NexeFile {
  filename: string;
  absPath: string;
  contents: string | Buffer;
}

export { NexeOptions };

export class NexeError extends Error {
  constructor(m: string) {
    super(m);
    Object.setPrototypeOf(this, NexeError.prototype);
  }
}

export class NexeCompiler {
  /**
   * Epoch of when compilation started
   */
  private start = Date.now();
  private compileStep: LogStep | undefined;
  public log = new Logger(this.options.loglevel);
  /**
   * Copy of process.env
   */
  public env = { ...process.env };
  /**
   * Virtual FileSystem
   */
  public bundle: Bundle;
  /**
   * Root directory for the source of the current build
   */
  public src: string;
  /**
   * In memory files that are being manipulated by the compiler
   */
  public files: NexeFile[] = [];
  /**
   * Standalone pieces of code run before the application entrypoint
   */
  public shims: string[] = [];
  /**
   * The last shim (defaults to "require('module').runMain()")
   */
  public startup = "";
  /**
   * The main entrypoint filename for your application - eg. node mainFile.js
   */
  public entrypoint: string | undefined;
  /**
   * Not used
   */
  public targets: NexeTarget[];
  /**
   * Current target of the compiler
   */
  public target: NexeTarget;
  /**
   * Output filename (-o myapp.exe)
   */
  public output = this.options.output;
  /**
   * Flag to indicate whether or notstdin was used for input
   */
  public stdinUsed = false;
  /**
   * Path to the configure script
   */
  public configureScript: string;
  /**
   * The file path of node binary
   */
  public nodeSrcBinPath: string;
  /**
   * Remote asset path if available
   */
  public remoteAsset: string;

  constructor(public options: NexeOptions) {
    const { python } = (this.options = options);
    //SOMEDAY iterate over multiple targets with `--outDir`
    this.targets = options.targets as NexeTarget[];
    this.target = this.targets[0];
    if (!/https?\:\/\//.test(options.remote)) {
      throw new NexeError(
        `Invalid remote URI scheme (must be http or https): ${options.remote}`
      );
    }
    this.remoteAsset = options.remote + this.target.toString();
    this.src = join(this.options.temp, this.target.version);
    this.configureScript =
      configure + (semverGt(this.target.version, "10.10.0") ? ".py" : "");
    this.nodeSrcBinPath = isWindows
      ? join(this.src, "Release", "node.exe")
      : join(this.src, "out", "Release", "node");
    this.log.step("nexe " + version, "info");
    this.bundle = new Bundle(options);
    if (isWindows) {
      const originalPath = process.env.PATH;
      delete process.env.PATH;
      this.env = { ...process.env };
      this.env.PATH = python
        ? (this.env.PATH =
          dequote(normalize(python)) + delimiter + originalPath)
        : originalPath;
      process.env.PATH = originalPath;
    } else {
      this.env = { ...process.env };
      python && (this.env.PYTHON = python);
    }
  }

  @bound
  addResource(absoluteFileName: string, content?: Buffer | string | File) {
    return this.bundle.addResource(absoluteFileName, content);
  }

  @bound
  async readFileAsync(file: string) {
    this.assertBuild();
    let cachedFile = this.files.find(
      (x) => normalize(x.filename) === normalize(file)
    );
    if (!cachedFile) {
      const absPath = join(this.src, file);
      cachedFile = {
        absPath,
        filename: file,
        contents: await readFileAsync(absPath, "utf-8").catch((x) => {
          if (x.code === "ENOENT") return "";
          throw x;
        }),
      };
      this.files.push(cachedFile);
    }
    return cachedFile;
  }

  @bound
  writeFileAsync(file: string, contents: string | Buffer) {
    this.assertBuild();
    return writeFileAsync(join(this.src, file), contents);
  }

  @bound
  async replaceInFileAsync(
    file: string,
    replace: string | RegExp,
    value: string | StringReplacer
  ) {
    const entry = await this.readFileAsync(file);
    entry.contents = entry.contents.toString().replace(replace, value as any);
  }

  @bound
  async setFileContentsAsync(file: string, contents: string | Buffer) {
    const entry = await this.readFileAsync(file);
    entry.contents = contents;
  }

  quit(error?: any) {
    const time = Date.now() - this.start;
    this.log.write(`Finished in ${time / 1000}s`, error ? "red" : "green");
    return this.log.flush();
  }

  assertBuild() {
    if (!this.options.build) {
      throw new NexeError("This feature is only available with `--build`");
    }
  }

  public getNodeExecutableLocation(target?: NexeTarget) {
    if (this.options.asset) {
      return resolve(this.options.cwd, this.options.asset);
    }
    if (target) {
      return join(this.options.temp, target.toString());
    }
    return this.nodeSrcBinPath;
  }

  private _runBuildCommandAsync(command: string, args: string[]) {
    if (this.log.verbose) {
      this.compileStep!.pause();
    }
    return new Promise<void>((resolve, reject) => {
      spawn(command, args, {
        cwd: this.src,
        env: this.env,
        shell: true,
        stdio: this.log.verbose ? "inherit" : "ignore",
      })
        .once("error", (e: Error) => {
          if (this.log.verbose) {
            this.compileStep!.resume();
          }
          reject(e);
        })
        .once("close", (code: number) => {
          if (this.log.verbose) {
            this.compileStep!.resume();
          }
          if (code != 0) {
            const error = `${command} ${args.join(
              " "
            )} exited with code: ${code}`;
            reject(new NexeError(error));
          }
          resolve();
        });
    });
  }

  private _configureAsync() {
    if (isWindows && semverGt(this.target.version, "10.15.99")) {
      return Promise.resolve();
    }
    return this._runBuildCommandAsync(this.env.PYTHON || "python", [
      this.configureScript,
      ...this.options.configure,
    ]);
  }

  public async build(): Promise<ReadStream> {
    this.compileStep!.log(
      `Configuring node build${this.options.configure.length ? ": " + this.options.configure : "..."
      }`
    );
    await this._configureAsync();
    const buildOptions = this.options.make;
    this.compileStep!.log(
      `Compiling Node${buildOptions.length ? " with arguments: " + buildOptions : "..."
      }`
    );
    await this._runBuildCommandAsync(make, buildOptions);
    return createReadStream(this.getNodeExecutableLocation());
  }

  private async _shouldCompileBinaryAsync(
    binary: NodeJS.ReadableStream | null,
    location: string
  ) {
    //SOMEDAY combine make/configure/vcBuild/and modified times of included files
    const { snapshot, build } = this.options;

    if (!binary) {
      return true;
    }

    if (build && snapshot != null && (await pathExistsAsync(snapshot))) {
      const snapshotLastModified = (await statAsync(snapshot)).mtimeMs;
      const binaryLastModified = (await statAsync(location)).mtimeMs;
      return snapshotLastModified > binaryLastModified;
    }

    return false;
  }

  async compileAsync(target: NexeTarget) {
    const step = (this.compileStep = this.log.step("Compiling result"));
    const build = this.options.build;
    const location = this.getNodeExecutableLocation(build ? undefined : target);
    let binary = (await pathExistsAsync(location))
      ? createReadStream(location)
      : null;

    if (await this._shouldCompileBinaryAsync(binary, location)) {
      binary = await this.build();
      step.log("Node binary compiled");
    }
    return this._assembleDeliverable(binary!);
  }

  code() {
    return [this.shims.join(""), this.startup].join(";");
  }

  private async _assembleDeliverable(binary: Readable) {
    if (!this.options.mangle) {
      return binary;
    }
    const launchCode = this.code();
    const codeSize = Buffer.byteLength(launchCode);
    const sentinel = Buffer.from("<nexe~~sentinel>");

    let vfsSize = 0;
    const streams = [
      binary,
      toStream(launchCode),
      this.bundle.toStream().pipe(
        new Transform({
          transform: (chunk, _, cb) => {
            vfsSize || this.bundle.finalize();
            chunk && (vfsSize += chunk.length);
            cb(null, chunk);
          },
        })
      ),
    ];

    let done = false;
    return new MultiStream((cb) => {
      if (done) cb(null, null);
      else if (streams.length) cb(null, streams.shift() as Readable);
      else {
        done = true;
        const trailers = Buffer.alloc(16);
        trailers.writeDoubleLE(codeSize, 0);
        trailers.writeDoubleLE(vfsSize, 8);
        cb(null, toStream(Buffer.concat([sentinel, trailers])));
      }
    });
  }
}