/**
 * Forgejo API client.
 *
 * Endpoints used:
 *   GET  /api/v1/user                -> verify credentials / obtain login name
 *   POST /api/v1/users/{login}/tokens -> create a personal access token
 *   DELETE /api/v1/users/{login}/tokens/{id} -> revoke a personal access token
 */
class ForgejoClient {
  constructor(baseUrl, token = null) {
    this.baseUrl = baseUrl.replace(/\/$/, '');
    this.token = token;
  }

  static fromConfig(config) {
    if (!config || !config.url || !config.token) {
      throw new Error('Not authenticated. Run: forgejo auth login');
    }
    return new ForgejoClient(config.url, config.token);
  }

  withBasicAuth(username, password) {
    const clone = new ForgejoClient(this.baseUrl, this.token);
    clone.basicAuth = Buffer.from(`${username}:${password}`).toString('base64');
    return clone;
  }

  headers(extra = {}) {
    const h = {
      Accept: 'application/json',
      'Content-Type': 'application/json',
      'User-Agent': 'forgejo-cli/1.0.0',
      ...extra,
    };
    if (this.token) {
      h.Authorization = `token ${this.token}`;
    } else if (this.basicAuth) {
      h.Authorization = `Basic ${this.basicAuth}`;
    }
    return h;
  }

  async request(method, endpoint, body = null) {
    const url = `${this.baseUrl}/api/v1${endpoint}`;
    const opts = {
      method,
      headers: this.headers(),
    };
    if (body !== null) {
      opts.body = JSON.stringify(body);
    }

    let res;
    try {
      res = await fetch(url, opts);
    } catch (err) {
      throw new Error(`Network error reaching ${this.baseUrl}: ${err.message}`);
    }

    const text = await res.text();
    let data = null;
    if (text) {
      try {
        data = JSON.parse(text);
      } catch {
        data = { raw: text };
      }
    }

    if (!res.ok) {
      const msg = data?.message || data?.raw || `HTTP ${res.status}`;
      const err = new Error(msg);
      err.status = res.status;
      err.body = data;
      throw err;
    }

    return data;
  }

  get(endpoint) {
    return this.request('GET', endpoint);
  }

  post(endpoint, body) {
    return this.request('POST', endpoint, body);
  }

  del(endpoint) {
    return this.request('DELETE', endpoint);
  }

  async verifyBasicAuth(username, password) {
    const client = this.withBasicAuth(username, password);
    return client.get('/user');
  }

  async createToken(username, password, name, scopes) {
    const client = this.withBasicAuth(username, password);
    return client.post(`/users/${encodeURIComponent(username)}/tokens`, { name, scopes });
  }

  async deleteToken(login, id) {
    return this.del(`/users/${encodeURIComponent(login)}/tokens/${id}`);
  }

  async createRepo(payload) {
    return this.post('/user/repos', payload);
  }

  async migrateRepo(payload) {
    return this.post('/repos/migrate', payload);
  }

  async getAll(endpoint, params = {}) {
    const pageSize = 50;
    const all = [];
    for (let page = 1; page <= 1000; page += 1) {
      const query = new URLSearchParams({ ...params, limit: String(pageSize), page: String(page) }).toString();
      const items = await this.get(`${endpoint}?${query}`);
      if (!Array.isArray(items) || items.length === 0) break;
      all.push(...items);
      if (items.length < pageSize) break;
    }
    return all;
  }

  async listRepos(opts = {}) {
    return this.getAll('/user/repos', opts);
  }

  async listIssues(owner, repo, opts = {}) {
    const params = {};
    if (opts.state) params.state = opts.state;
    if (opts.type) params.type = opts.type;
    return this.getAll(`/repos/${encodeURIComponent(owner)}/${encodeURIComponent(repo)}/issues`, params);
  }

  async listPullRequests(owner, repo, opts = {}) {
    return this.getAll(`/repos/${encodeURIComponent(owner)}/${encodeURIComponent(repo)}/pulls`, opts);
  }

  async listBranches(owner, repo, opts = {}) {
    return this.getAll(`/repos/${encodeURIComponent(owner)}/${encodeURIComponent(repo)}/branches`, opts);
  }
}

module.exports = { ForgejoClient };