const { spawn, execFile } = require('child_process');
const path = require('path');
const fs = require('fs');
const { resolvePackagedRuntime, resolveRuntimeStrategy } = require('./path-utils');

/**
 * InfluxDB 进程管理器。
 * 参照 MySQL 绿色包模式，随应用启动本地 InfluxDB，退出时只清理本应用记录的进程。
 */
class InfluxDBProcessManager {
  constructor(logWindowManager = null) {
    const runtime = resolvePackagedRuntime();
    const baseDir = runtime.baseDir;
    const sourceInfluxdbPath = !runtime.isPackaged
      ? path.join(baseDir, 'build', 'extraResources', 'influxdb-1.7.0')
      : path.join(baseDir, 'influxdb-1.7.0');
    const pathStrategy = resolveRuntimeStrategy(baseDir);

    this.baseDir = baseDir;
    this.pathStrategy = pathStrategy;
    this.sourceInfluxdbPath = sourceInfluxdbPath;
    this.influxdbPath = pathStrategy.usesSafePaths
      ? path.join(pathStrategy.safeRuntimeRoot, 'influxdb-1.7.0')
      : sourceInfluxdbPath;
    this.dataPath = path.join(this.influxdbPath, 'data');
    this.metaPath = path.join(this.influxdbPath, 'meta');
    this.walPath = path.join(this.influxdbPath, 'wal');
    this.configFile = path.join(this.influxdbPath, 'influxdb.runtime.conf');
    this.processRecordFile = path.join(this.influxdbPath, '.running-process.json');
    this.logWindowManager = logWindowManager;
    this.influxdbProcess = null;
    this.currentPort = null;
  }

  sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
  }

  log(type, message) {
    console.log(`[InfluxDB] ${message}`);
    if (this.logWindowManager) {
      this.logWindowManager.addLog(type, `[InfluxDB] ${message}`);
    }
  }

  normalizeComparablePath(target = '') {
    return String(target).replace(/"/g, '').replace(/\//g, '\\').toLowerCase();
  }

  copyDirectorySync(sourceDir, targetDir) {
    if (!fs.existsSync(sourceDir)) {
      return;
    }

    fs.mkdirSync(targetDir, { recursive: true });

    const entries = fs.readdirSync(sourceDir, { withFileTypes: true });
    entries.forEach((entry) => {
      const sourcePath = path.join(sourceDir, entry.name);
      const targetPath = path.join(targetDir, entry.name);

      if (entry.isDirectory()) {
        this.copyDirectorySync(sourcePath, targetPath);
        return;
      }

      let shouldCopy = !fs.existsSync(targetPath);
      if (!shouldCopy) {
        const sourceStat = fs.statSync(sourcePath);
        const targetStat = fs.statSync(targetPath);
        shouldCopy = sourceStat.size !== targetStat.size || sourceStat.mtimeMs > targetStat.mtimeMs;
      }

      if (shouldCopy) {
        fs.copyFileSync(sourcePath, targetPath);
      }
    });
  }

  ensureRuntimeEnvironment() {
    if (!fs.existsSync(this.sourceInfluxdbPath)) {
      throw new Error(`InfluxDB 目录不存在: ${this.sourceInfluxdbPath}`);
    }

    if (this.pathStrategy.usesSafePaths) {
      this.log('system', '检测到应用路径包含非 ASCII 字符，启用 InfluxDB 英文安全运行目录');
      this.log('system', `InfluxDB 源目录: ${this.sourceInfluxdbPath}`);
      this.log('system', `InfluxDB 运行目录: ${this.influxdbPath}`);
      this.copyDirectorySync(this.sourceInfluxdbPath, this.influxdbPath);
    }

    fs.mkdirSync(this.dataPath, { recursive: true });
    fs.mkdirSync(this.metaPath, { recursive: true });
    fs.mkdirSync(this.walPath, { recursive: true });
  }

  saveProcessRecord(record = {}) {
    try {
      fs.mkdirSync(path.dirname(this.processRecordFile), { recursive: true });
      fs.writeFileSync(this.processRecordFile, JSON.stringify(record, null, 2), 'utf-8');
    } catch (error) {
      this.log('warn', `写入 InfluxDB 进程标记失败: ${error.message}`);
    }
  }

  getProcessRecord() {
    try {
      if (!fs.existsSync(this.processRecordFile)) {
        return null;
      }

      return JSON.parse(fs.readFileSync(this.processRecordFile, 'utf-8'));
    } catch (error) {
      this.log('warn', `读取 InfluxDB 进程标记失败: ${error.message}`);
      return null;
    }
  }

  clearProcessRecord() {
    try {
      if (fs.existsSync(this.processRecordFile)) {
        fs.unlinkSync(this.processRecordFile);
      }
    } catch (error) {
      this.log('warn', `清理 InfluxDB 进程标记失败: ${error.message}`);
    }
  }

  execFileCommand(command, args = []) {
    return new Promise((resolve, reject) => {
      execFile(command, args, { encoding: 'utf8', windowsHide: true }, (error, stdout, stderr) => {
        if (error) {
          const err = new Error(error.message || stderr || stdout || 'Command execution failed');
          err.code = error.code;
          err.stdout = stdout;
          err.stderr = stderr;
          reject(err);
        } else {
          resolve({ stdout, stderr });
        }
      });
    });
  }

  async getProcessInfoByPid(pid) {
    if (!pid) {
      return null;
    }

    try {
      const script = `$proc = Get-CimInstance Win32_Process -Filter "ProcessId = ${pid}"; if ($proc) { [PSCustomObject]@{ executablePath = $proc.ExecutablePath; commandLine = $proc.CommandLine; name = $proc.Name } | ConvertTo-Json -Compress }`;
      const { stdout } = await this.execFileCommand('powershell.exe', ['-NoProfile', '-Command', script]);
      const raw = (stdout || '').trim();
      return raw ? JSON.parse(raw) : null;
    } catch (error) {
      return null;
    }
  }

  async isOwnInfluxDBProcess(pid, record = this.getProcessRecord()) {
    const processInfo = await this.getProcessInfoByPid(pid);
    if (!processInfo) {
      return false;
    }

    const expectedExe = this.normalizeComparablePath(path.join(this.influxdbPath, 'influxd.exe'));
    const expectedBat = this.normalizeComparablePath(path.join(this.influxdbPath, 'start-influxdb.bat'));
    const expectedConfig = this.normalizeComparablePath((record && record.configFile) || this.configFile);
    const executablePath = this.normalizeComparablePath(processInfo.executablePath);
    const commandLine = this.normalizeComparablePath(processInfo.commandLine);

    return (
      (executablePath === expectedExe || commandLine.includes(expectedBat)) &&
      (!expectedConfig || commandLine.includes(expectedConfig))
    );
  }

  async waitForProcessExit(pid, timeoutMs = 3000) {
    const deadline = Date.now() + timeoutMs;

    while (Date.now() < deadline) {
      const processInfo = await this.getProcessInfoByPid(pid);
      if (!processInfo) {
        return true;
      }
      await this.sleep(200);
    }

    return false;
  }

  async terminateTrackedProcess(record = this.getProcessRecord(), reason = '正在停止 InfluxDB 进程...') {
    const pid = this.influxdbProcess?.pid || record?.pid;
    const port = this.currentPort || record?.port;

    if (!pid) {
      this.log('system', '未找到可清理的 InfluxDB 进程标记');
      this.clearProcessRecord();
      return false;
    }

    const isOwnProcess = await this.isOwnInfluxDBProcess(pid, record);
    if (!isOwnProcess) {
      this.log('warn', `PID ${pid} 不是当前应用的 InfluxDB 进程，跳过清理`);
      this.clearProcessRecord();
      if (this.influxdbProcess && this.influxdbProcess.pid === pid) {
        this.influxdbProcess = null;
      }
      return false;
    }

    this.log('system', `${reason} PID=${pid}${port ? `, 端口=${port}` : ''}`);
    try {
      await this.execFileCommand('taskkill.exe', ['/F', '/T', '/PID', String(pid)]);
      await this.waitForProcessExit(pid, 3000);
      this.log('success', 'InfluxDB 进程已停止');
    } finally {
      this.clearProcessRecord();
      if (this.influxdbProcess && this.influxdbProcess.pid === pid) {
        this.influxdbProcess = null;
      }
      this.currentPort = null;
    }

    return true;
  }

  async checkAndKillOrphanProcess() {
    const record = this.getProcessRecord();
    if (!record || !record.pid) {
      return;
    }

    const isOwnProcess = await this.isOwnInfluxDBProcess(record.pid, record);
    if (!isOwnProcess) {
      this.log('warn', `检测到失效的 InfluxDB 进程标记 PID=${record.pid}，已跳过清理并移除标记`);
      this.clearProcessRecord();
      return;
    }

    this.log('warn', `检测到当前应用上次遗留的 InfluxDB 进程 PID=${record.pid}，开始定向清理...`);
    await this.terminateTrackedProcess(record, '正在清理当前应用遗留的 InfluxDB 进程...');
  }

  generateConfig(port) {
    const normalizePath = target => target.replace(/\\/g, '/');
    const config = `reporting-disabled = true
bind-address = "127.0.0.1:8088"

[meta]
  dir = "${normalizePath(this.metaPath)}"

[data]
  dir = "${normalizePath(this.dataPath)}"
  wal-dir = "${normalizePath(this.walPath)}"

[http]
  enabled = true
  bind-address = "127.0.0.1:${port}"
  auth-enabled = false
  log-enabled = true
`;

    fs.writeFileSync(this.configFile, config, 'utf-8');
    this.log('system', `生成 InfluxDB 配置文件，端口: ${port}`);
  }

  async startInfluxDBProcess(port) {
    return new Promise((resolve, reject) => {
      const influxd = path.join(this.influxdbPath, 'influxd.exe');
      const startBat = path.join(this.influxdbPath, 'start-influxdb.bat');

      this.log('system', '正在启动 InfluxDB 进程...');
      this.log('system', `可执行文件: ${influxd}`);
      this.log('system', `启动脚本: ${startBat}`);
      this.log('system', `配置文件: ${this.configFile}`);

      if (!fs.existsSync(influxd)) {
        return reject(new Error(`influxd.exe 不存在: ${influxd}`));
      }
      if (!fs.existsSync(startBat)) {
        return reject(new Error(`start-influxdb.bat 不存在: ${startBat}`));
      }
      if (!fs.existsSync(this.configFile)) {
        return reject(new Error(`配置文件不存在: ${this.configFile}`));
      }

      const influxdbProcess = spawn('cmd.exe', ['/d', '/s', '/c', 'call', startBat, this.configFile], {
        cwd: this.influxdbPath,
        stdio: ['ignore', 'pipe', 'pipe'],
        windowsHide: true
      });
      this.influxdbProcess = influxdbProcess;
      this.currentPort = port;

      this.saveProcessRecord({
        pid: influxdbProcess.pid,
        port,
        executablePath: influxd,
        configFile: this.configFile,
        influxdbPath: this.influxdbPath,
        createdAt: new Date().toISOString()
      });

      let startupComplete = false;
      let startupTimeout = null;

      const completeStartup = () => {
        if (!startupComplete) {
          startupComplete = true;
          if (startupTimeout) clearTimeout(startupTimeout);
          this.log('success', 'InfluxDB 进程已就绪');
          resolve(true);
        }
      };

      const handleOutput = (data) => {
        const msg = data.toString().trim();
        if (!msg) {
          return;
        }

        if (msg.includes('Listening on HTTP') || msg.includes('Listening for signals')) {
          completeStartup();
        }

        if (!msg.includes('[I]') || msg.includes('Listening') || msg.includes('error')) {
          this.log('system', `[influxd] ${msg}`);
        }
      };

      influxdbProcess.stdout.on('data', handleOutput);
      influxdbProcess.stderr.on('data', handleOutput);

      influxdbProcess.on('error', (err) => {
        this.log('error', `InfluxDB 进程启动失败: ${err.message}`);
        this.clearProcessRecord();
        this.influxdbProcess = null;
        reject(err);
      });

      influxdbProcess.on('exit', (code, signal) => {
        this.log('system', `InfluxDB 进程退出，代码: ${code}, 信号: ${signal}`);
        const record = this.getProcessRecord();
        if (record && record.pid === influxdbProcess.pid) {
          this.clearProcessRecord();
        }
        this.influxdbProcess = null;
        this.currentPort = null;

        if (!startupComplete) {
          reject(new Error(`InfluxDB 进程异常退出，代码: ${code}`));
        }
      });

      startupTimeout = setTimeout(completeStartup, 15000);
    });
  }

  async stopInfluxDBProcess() {
    const record = this.getProcessRecord();
    if (!this.influxdbProcess && !record) {
      this.log('system', 'InfluxDB 进程未运行');
      return;
    }

    await this.terminateTrackedProcess(record, '正在停止当前应用自己的 InfluxDB 进程...');
  }

  isInfluxDBRunning() {
    return this.influxdbProcess !== null && !this.influxdbProcess.killed;
  }

  async ensureServiceRunning(findAvailablePort, waitForPort) {
    this.ensureRuntimeEnvironment();

    this.log('system', '开始 InfluxDB 进程检查流程（进程模式）');
    this.log('system', `路径策略: ${this.pathStrategy.usesSafePaths ? '英文安全路径模式' : '应用目录直启模式'}`);
    this.log('system', `InfluxDB 路径: ${this.influxdbPath}`);
    this.log('system', `配置文件: ${this.configFile}`);

    if (this.isInfluxDBRunning()) {
      const port = this.currentPort || 18086;
      this.log('success', `InfluxDB 进程已在运行，端口: ${port}`);
      return port;
    }

    await this.checkAndKillOrphanProcess();

    const port = await findAvailablePort(18086, 100);
    if (port === -1) {
      throw new Error('无法找到可用的 InfluxDB 端口（18086-18185 全部被占用）');
    }
    this.log('system', `找到可用端口: ${port}`);

    this.generateConfig(port);
    await this.startInfluxDBProcess(port);

    this.log('system', `等待端口 ${port} 就绪...`);
    const portReady = await waitForPort(port, 30000);
    if (!portReady) {
      throw new Error(`InfluxDB 端口 ${port} 未能在 30 秒内就绪`);
    }

    this.log('success', `InfluxDB 进程启动成功，端口: ${port}`);
    return port;
  }
}

module.exports = InfluxDBProcessManager;