import fs from "fs";
import path from "path";
import { execSync } from "child_process";

// ============================================================
// 版本更新模块
// 用于检查远程仓库版本并执行 Docker 容器更新
// ============================================================

/** .version JSON 文件结构 */
export interface VersionFile {
  version: string;
  release_date: string;
  changelog: string;
}

/** 版本信息（API 返回给前端） */
export interface VersionInfo {
  current: VersionFile;
  latest: VersionFile | null;
  hasUpdate: boolean;
  currentCommit?: string;
  latestCommit?: string;
  /** 状态消息，如 "远程仓库未包含 .version 文件" */
  message?: string;
}

/** 默认版本文件 */
const DEFAULT_VERSION: VersionFile = {
  version: "0.0.0",
  release_date: "",
  changelog: "",
};

/** 更新配置 */
interface UpdateConfig {
  remoteUrl: string;
  accessToken: string;
}

/** 更新日志回调 */
export type LogCallback = (message: string) => void;

/** 空回调 */
const noopLog: LogCallback = () => {};

/**
 * 读取并解析本地的 .version 文件
 */
export function readLocalVersionFile(): VersionFile {
  try {
    const versionPath = path.join(process.cwd(), ".version");
    const content = fs.readFileSync(versionPath, "utf-8").trim();
    return JSON.parse(content) as VersionFile;
  } catch {
    return DEFAULT_VERSION;
  }
}

/**
 * 获取更新配置
 */
function getUpdateConfig(): UpdateConfig {
  return {
    remoteUrl:
      process.env.GIT_REMOTE_URL || "https://git.hanhan.ltd/recipe_tool.git",
    accessToken: process.env.ONEDEV_ACCESS_TOKEN || "",
  };
}

/**
 * 构建带认证的远程 URL
 */
function getAuthenticatedRemoteUrl(): string {
  const config = getUpdateConfig();
  if (!config.accessToken) return config.remoteUrl;
  const url = new URL(config.remoteUrl);
  url.username = "access-token";
  url.password = config.accessToken;
  return url.toString();
}

/**
 * 通过 git ls-remote 获取远程最新 commit hash
 */
export function getRemoteCommitHash(): string | null {
  try {
    const url = getAuthenticatedRemoteUrl();
    const output = execSync(`git ls-remote "${url}" HEAD`, {
      encoding: "utf-8",
      timeout: 15000,
      env: {
        ...process.env,
        GIT_TERMINAL_PROMPT: "0",
      },
      windowsHide: true,
    });
    const match = output.match(/^([a-f0-9]+)\s+HEAD/m);
    return match?.[1] || null;
  } catch {
    return null;
  }
}

/**
 * 获取远程 .version 文件内容并解析为 VersionFile
 */
export function getRemoteVersionFile(): VersionFile | null {
  // 尝试方式1: git archive
  try {
    const url = getAuthenticatedRemoteUrl();
    const output = execSync(
      `git archive --remote="${url}" HEAD:.version 2>nul`,
      {
        encoding: "utf-8",
        timeout: 15000,
        windowsHide: true,
      }
    );
    const parsed = JSON.parse(output.trim()) as VersionFile;
    if (parsed.version) return parsed;
  } catch {
    // fall through
  }

  // 尝试方式2: 浅克隆
  return getRemoteVersionByClone();
}

/**
 * 通过浅克隆获取远程 .version 文件（备选方案）
 */
function getRemoteVersionByClone(): VersionFile | null {
  const tmpDir = path.join(
    process.env.TEMP || "/tmp",
    `recipe_tool_version_${Date.now()}`
  );
  try {
    const url = getAuthenticatedRemoteUrl();
    execSync(
      `git clone --depth 1 --filter=blob:none --sparse "${url}" "${tmpDir}" 2>nul`,
      {
        encoding: "utf-8",
        timeout: 30000,
        windowsHide: true,
      }
    );
    execSync(`cd "${tmpDir}" && git sparse-checkout set .version 2>nul`, {
      encoding: "utf-8",
      timeout: 10000,
      windowsHide: true,
    });
    const versionPath = path.join(tmpDir, ".version");
    if (fs.existsSync(versionPath)) {
      const content = fs.readFileSync(versionPath, "utf-8").trim();
      return JSON.parse(content) as VersionFile;
    }
    return null;
  } catch {
    return null;
  } finally {
    try {
      fs.rmSync(tmpDir, { recursive: true, force: true });
    } catch {
      // ignore cleanup errors
    }
  }
}

/**
 * 比较两个语义化版本号
 * 返回: 1 = v1 > v2, -1 = v1 < v2, 0 = equal
 */
export function compareVersions(v1: string, v2: string): number {
  const parts1 = v1.split(".").map(Number);
  const parts2 = v2.split(".").map(Number);

  for (let i = 0; i < Math.max(parts1.length, parts2.length); i++) {
    const p1 = parts1[i] || 0;
    const p2 = parts2[i] || 0;
    if (p1 > p2) return 1;
    if (p1 < p2) return -1;
  }
  return 0;
}

/**
 * 检查是否有可用更新
 */
export async function checkForUpdate(): Promise<VersionInfo> {
  const current = readLocalVersionFile();
  const remoteCommit = getRemoteCommitHash();

  if (!remoteCommit) {
    return {
      current,
      latest: null,
      hasUpdate: false,
      message: "无法连接到远程仓库，请检查网络和 ONEDEV_ACCESS_TOKEN 配置",
    };
  }

  const remoteVersionFile = getRemoteVersionFile();

  if (remoteVersionFile) {
    const cmp = compareVersions(remoteVersionFile.version, current.version);
    return {
      current,
      latest: remoteVersionFile,
      hasUpdate: cmp > 0,
      latestCommit: remoteCommit,
    };
  }

  // 远程能连上但 .version 文件不存在或解析失败
  return {
    current,
    latest: null,
    hasUpdate: false,
    latestCommit: remoteCommit,
    message:
      "远程仓库中未找到 .version 文件。\n" +
      "请确保 .version 文件已提交并推送到远程仓库：\n" +
      "  git add .version && git commit -m \"add version file\" && git push",
  };
}

/**
 * 执行 Docker 容器更新
 * @param onLog 日志回调
 */
export async function executeUpdate(
  onLog: LogCallback = noopLog
): Promise<{ success: boolean; message: string }> {
  const tmpDir = path.join(
    process.env.TEMP || "/tmp",
    `recipe_tool_update_${Date.now()}`
  );

  try {
    onLog("开始更新流程...\n");

    // 1. 拉取最新代码
    const url = getAuthenticatedRemoteUrl();
    onLog(`[1/4] 克隆最新代码...\n`);
    execSync(`git clone --depth 1 "${url}" "${tmpDir}"`, {
      encoding: "utf-8",
      timeout: 120000,
      windowsHide: true,
      stdio: ["ignore", "pipe", "pipe"],
    });
    onLog(`✓ 代码拉取完成\n`);

    // 2. 生成 .env 文件
    onLog(`[2/4] 准备环境变量...\n`);
    const envContent = [
      `DB_HOST=${process.env.DB_HOST || "127.0.0.1"}`,
      `DB_PORT=${process.env.DB_PORT || "3306"}`,
      `DB_USER=${process.env.DB_USER || "root"}`,
      `DB_PASSWORD=${process.env.DB_PASSWORD || ""}`,
      `DB_NAME=${process.env.DB_NAME || "recipe_tools"}`,
      `AI_API_KEY=${process.env.AI_API_KEY || ""}`,
      `AI_BASE_URL=${process.env.AI_BASE_URL || "https://api.openai.com/v1"}`,
      `AI_MODEL=${process.env.AI_MODEL || "gpt-3.5-turbo"}`,
      `ONEDEV_ACCESS_TOKEN=${process.env.ONEDEV_ACCESS_TOKEN || ""}`,
    ].join("\n");
    fs.writeFileSync(path.join(tmpDir, ".env"), envContent, "utf-8");
    onLog(`✓ 环境变量已准备\n`);

    // 3. 构建新镜像
    onLog(`[3/4] 构建新 Docker 镜像...\n`);
    execSync(`cd "${tmpDir}" && docker compose -p recipe_tool build`, {
      encoding: "utf-8",
      timeout: 600000,
      windowsHide: true,
      stdio: ["ignore", "pipe", "pipe"],
    });
    onLog(`✓ 镜像构建完成\n`);

    // 4. 重启服务
    onLog(`[4/4] 重启服务...\n`);
    execSync(`cd "${tmpDir}" && docker compose -p recipe_tool up -d`, {
      encoding: "utf-8",
      timeout: 60000,
      windowsHide: true,
      stdio: ["ignore", "pipe", "pipe"],
    });
    onLog(`✓ 服务已重启\n`);

    return { success: true, message: "更新完成" };
  } catch (error) {
    const errMsg = error instanceof Error ? error.message : "未知错误";
    onLog(`✗ 更新失败: ${errMsg}\n`);
    return { success: false, message: errMsg };
  } finally {
    try {
      fs.rmSync(tmpDir, { recursive: true, force: true });
    } catch {
      // ignore cleanup errors
    }
  }
}