/**
 * skill-review handler
 * 提供 Gitea API 操作的輔助函式，供 agent 審查 skill 並提交 PR。
 */

const GITEA_URL = process.env.GITEA_URL || 'https://git.nature.edu.kg';
const UPSTREAM_OWNER = 'Selig';
const REPO_NAME = 'openclaw-skill';

// Agent ID → Gitea 帳號 & token 環境變數對應
const AGENT_MAP: Record<string, { username: string; tokenEnv: string }> = {
  tiangong: { username: 'tiangong', tokenEnv: 'GITEA_TOKEN_TIANGONG' },
  kaiwu: { username: 'kaiwu', tokenEnv: 'GITEA_TOKEN_KAIWU' },
  yucheng: { username: 'yucheng', tokenEnv: 'GITEA_TOKEN_YUCHENG' },
};

interface GiteaFile {
  name: string;
  path: string;
  sha: string;
  content?: string;
  encoding?: string;
}

async function giteaApi(
  token: string,
  method: string,
  path: string,
  body?: any
): Promise<any> {
  const url = `${GITEA_URL}/api/v1${path}`;
  const opts: RequestInit = {
    method,
    headers: {
      Authorization: `token ${token}`,
      'Content-Type': 'application/json',
    },
  };
  if (body) opts.body = JSON.stringify(body);
  const res = await fetch(url, opts);
  const text = await res.text();
  if (!res.ok) {
    throw new Error(`Gitea API ${method} ${path} → ${res.status}: ${text}`);
  }
  return text ? JSON.parse(text) : null;
}

/** 同步 fork（用 Gitea merge upstream API） */
async function syncFork(token: string, owner: string): Promise<void> {
  try {
    // Gitea 1.25: POST /repos/{owner}/{repo}/merge-upstream
    await giteaApi(token, 'POST', `/repos/${owner}/${REPO_NAME}/merge-upstream`, {
      branch: 'main',
    });
  } catch (e: any) {
    // 如果 API 不存在或已同步，忽略
    if (!e.message.includes('409')) {
      console.warn('syncFork warning:', e.message);
    }
  }
}

/** 列出 skills 目錄下的所有 skill */
async function listSkills(token: string, owner: string): Promise<string[]> {
  const items = await giteaApi(
    token,
    'GET',
    `/repos/${owner}/${REPO_NAME}/contents/skills?ref=main`
  );
  return items
    .filter((item: any) => item.type === 'dir')
    .map((item: any) => item.name);
}

/** 讀取檔案內容 */
async function readFile(
  token: string,
  owner: string,
  filepath: string,
  ref = 'main'
): Promise<GiteaFile> {
  return giteaApi(
    token,
    'GET',
    `/repos/${owner}/${REPO_NAME}/contents/${filepath}?ref=${ref}`
  );
}

/** 建立分支 */
async function createBranch(
  token: string,
  owner: string,
  branchName: string
): Promise<void> {
  await giteaApi(token, 'POST', `/repos/${owner}/${REPO_NAME}/branches`, {
    new_branch_name: branchName,
    old_branch_name: 'main',
  });
}

/** 更新檔案（需要 sha） */
async function updateFile(
  token: string,
  owner: string,
  filepath: string,
  content: string,
  sha: string,
  branch: string,
  message: string
): Promise<void> {
  const b64 = Buffer.from(content, 'utf-8').toString('base64');
  await giteaApi(
    token,
    'PUT',
    `/repos/${owner}/${REPO_NAME}/contents/${filepath}`,
    { content: b64, sha, message, branch }
  );
}

/** 建立新檔案 */
async function createFile(
  token: string,
  owner: string,
  filepath: string,
  content: string,
  branch: string,
  message: string
): Promise<void> {
  const b64 = Buffer.from(content, 'utf-8').toString('base64');
  await giteaApi(
    token,
    'POST',
    `/repos/${owner}/${REPO_NAME}/contents/${filepath}`,
    { content: b64, message, branch }
  );
}

/** 建立 PR（從 fork 到 upstream） */
async function createPR(
  token: string,
  agentUsername: string,
  title: string,
  body: string,
  branch: string
): Promise<{ url: string; number: number }> {
  const pr = await giteaApi(
    token,
    'POST',
    `/repos/${UPSTREAM_OWNER}/${REPO_NAME}/pulls`,
    {
      title,
      body,
      head: `${agentUsername}:${branch}`,
      base: 'main',
    }
  );
  return { url: pr.html_url, number: pr.number };
}

export async function handler(ctx: any) {
  // 偵測當前 agent
  const agentId = ctx.env?.OPENCLAW_AGENT_ID || ctx.agentId || 'unknown';
  const agentConfig = AGENT_MAP[agentId];

  if (!agentConfig) {
    return {
      reply: `❌ 無法辨識 agent: ${agentId}\n支援的 agent: ${Object.keys(AGENT_MAP).join(', ')}`,
    };
  }

  const token = ctx.env?.[agentConfig.tokenEnv] || process.env[agentConfig.tokenEnv];
  if (!token) {
    return {
      reply: `❌ 找不到 ${agentConfig.tokenEnv}，請確認 .env 設定。`,
    };
  }

  const username = agentConfig.username;

  try {
    // Step 1: 同步 fork
    await syncFork(token, username);

    // Step 2: 列出所有 skills
    const skills = await listSkills(token, username);

    // Step 3: 讀取每個 skill 的內容
    const skillContents: Record<string, { skillMd: string; handlerTs: string }> = {};

    for (const skill of skills) {
      try {
        const skillMdFile = await readFile(token, username, `skills/${skill}/SKILL.md`);
        const handlerFile = await readFile(token, username, `skills/${skill}/handler.ts`);

        skillContents[skill] = {
          skillMd: Buffer.from(skillMdFile.content || '', 'base64').toString('utf-8'),
          handlerTs: Buffer.from(handlerFile.content || '', 'base64').toString('utf-8'),
        };
      } catch {
        // 跳過讀取失敗的 skill
      }
    }

    // 回傳資料供 agent 分析
    return {
      reply: `✅ Fork 已同步，共讀取 ${Object.keys(skillContents).length} 個 skills。\n\n請根據你的角色審查以下 skills，選擇一個提出改進 PR。`,
      data: {
        agentId,
        username,
        skills: skillContents,
        // 提供 API helper 資訊，讓 agent 知道可以用 exec 呼叫
        api: {
          createBranch: 'handler.createBranch(token, owner, branchName)',
          updateFile: 'handler.updateFile(token, owner, filepath, content, sha, branch, message)',
          createFile: 'handler.createFile(token, owner, filepath, content, branch, message)',
          createPR: 'handler.createPR(token, agentUsername, title, body, branch)',
        },
      },
      metadata: { agentId, username, skillCount: Object.keys(skillContents).length },
    };
  } catch (err: any) {
    return {
      reply: `❌ 執行失敗: ${err.message}`,
      error: err.message,
    };
  }
}

// 匯出 helper 供 agent 透過 exec 使用
export {
  syncFork,
  listSkills,
  readFile,
  createBranch,
  updateFile,
  createFile,
  createPR,
  giteaApi,
  AGENT_MAP,
};