import { Category, Feed, FeedEntry, Stats, User } from '../types';

const API_BASE = '/api';

async function request<T>(path: string, options: RequestInit = {}): Promise<T> {
  const token = localStorage.getItem('rsspipe_jwt');
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    ...(options.headers as Record<string, string> || {}),
  };

  if (token) {
    headers['Authorization'] = `Bearer ${token}`;
  }

  const res = await fetch(`${API_BASE}${path}`, {
    ...options,
    headers,
    credentials: 'omit',
  });

  if (res.status === 401 && path !== '/auth/login') {
    localStorage.removeItem('rsspipe_jwt');
    window.dispatchEvent(new CustomEvent('auth:unauthorized'));
    throw new Error('Session expired or unauthorized');
  }

  if (!res.ok) {
    let errMsg = `Request failed: ${res.status} ${res.statusText}`;
    try {
      const errJson = await res.json();
      if (errJson.error) errMsg = errJson.error;
    } catch {
      // ignore
    }
    throw new Error(errMsg);
  }

  return res.json();
}

export const api = {
  // Auth
  async login(username: string, password: string): Promise<{ token: string; user: User }> {
    const res = await request<{ token: string; user: User }>('/auth/login', {
      method: 'POST',
      body: JSON.stringify({ username, password }),
    });
    if (res.token) {
      localStorage.setItem('rsspipe_jwt', res.token);
    }
    return res;
  },

  async logout(): Promise<void> {
    try {
      await request('/auth/logout', { method: 'POST' });
    } finally {
      localStorage.removeItem('rsspipe_jwt');
    }
  },

  async getMe(): Promise<User> {
    return request<User>('/auth/me');
  },

  async changePassword(old_password: string, new_password: string): Promise<{ message: string }> {
    return request<{ message: string }>('/auth/password', {
      method: 'PUT',
      body: JSON.stringify({ old_password, new_password }),
    });
  },

  // Stats
  async getStats(): Promise<Stats> {
    return request<Stats>('/stats');
  },

  // Categories
  async listCategories(): Promise<Category[]> {
    return request<Category[]>('/categories');
  },

  async createCategory(title: string): Promise<Category> {
    return request<Category>('/categories', {
      method: 'POST',
      body: JSON.stringify({ title }),
    });
  },

  async deleteCategory(id: string): Promise<void> {
    return request<void>(`/categories/${id}`, { method: 'DELETE' });
  },

  // Feeds
  async listFeeds(): Promise<Feed[]> {
    return request<Feed[]>('/feeds');
  },

  async createFeed(feed_url: string, category_id?: string, title?: string): Promise<Feed> {
    return request<Feed>('/feeds', {
      method: 'POST',
      body: JSON.stringify({ feed_url, category_id, title }),
    });
  },

  async updateFeed(
    id: string,
    data: {
      title?: string;
      category_id?: string;
      refresh_interval_minutes?: number;
      timeout_seconds?: number;
    }
  ): Promise<Feed> {
    return request<Feed>(`/feeds/${id}`, {
      method: 'PUT',
      body: JSON.stringify(data),
    });
  },

  async deleteFeed(id: string): Promise<void> {
    return request<void>(`/feeds/${id}`, { method: 'DELETE' });
  },

  async refreshFeed(id: string): Promise<Feed> {
    return request<Feed>(`/feeds/${id}/refresh`, { method: 'POST' });
  },

  async refreshAllFeeds(): Promise<void> {
    return request<void>('/feeds/refresh-all', { method: 'POST' });
  },

  // Entries
  async listEntries(params: {
    view?: string;
    feed_id?: string;
    category_id?: string;
    search?: string;
    limit?: number;
    offset?: number;
  }): Promise<{ entries: FeedEntry[]; total: number; limit: number; offset: number }> {
    const query = new URLSearchParams();
    if (params.view) query.set('view', params.view);
    if (params.feed_id) query.set('feed_id', params.feed_id);
    if (params.category_id) query.set('category_id', params.category_id);
    if (params.search) query.set('search', params.search);
    if (params.limit) query.set('limit', params.limit.toString());
    if (params.offset) query.set('offset', params.offset.toString());

    return request(`/entries?${query.toString()}`);
  },

  async updateRead(id: string, is_read: boolean): Promise<void> {
    return request(`/entries/${id}/read`, {
      method: 'PUT',
      body: JSON.stringify({ is_read }),
    });
  },

  async updateStar(id: string, is_starred: boolean): Promise<void> {
    return request(`/entries/${id}/star`, {
      method: 'PUT',
      body: JSON.stringify({ is_starred }),
    });
  },

  async markAllRead(feed_id?: string, category_id?: string): Promise<void> {
    return request('/entries/mark-all-read', {
      method: 'POST',
      body: JSON.stringify({ feed_id, category_id }),
    });
  },

  // OPML
  async importOPML(file: File): Promise<{ imported_count: number; total_parsed: number }> {
    const token = localStorage.getItem('rsspipe_jwt');
    const formData = new FormData();
    formData.append('file', file);

    const headers: Record<string, string> = {};
    if (token) headers['Authorization'] = `Bearer ${token}`;

    const res = await fetch(`${API_BASE}/opml/import`, {
      method: 'POST',
      headers,
      body: formData,
    });

    if (!res.ok) {
      const err = await res.json().catch(() => ({}));
      throw new Error(err.error || 'Failed to import OPML');
    }

    return res.json();
  },

  exportOPMLUrl(): string {
    const token = localStorage.getItem('rsspipe_jwt');
    return `${API_BASE}/opml/export?token=${token || ''}`;
  }
};