import axios from 'axios';
import { Config, Issue, Comment, RepoItem } from './types.js';

/**
 * Normalizes the Gitea/Forgejo URL by stripping trailing slashes
 * and ensuring it has a protocol (defaults to https).
 */
export function normalizeUrl(url: string): string {
  let cleaned = url.trim();
  if (!cleaned) return '';
  if (!/^https?:\/\//i.test(cleaned)) {
    cleaned = 'https://' + cleaned;
  }
  return cleaned.replace(/\/+$/, '');
}

/**
 * Creates an Axios instance with standard Gitea/Forgejo headers.
 */
function createAxiosInstance(config: Config) {
  const headers: Record<string, string> = {
    'Accept': 'application/json',
    'Content-Type': 'application/json',
  };

  if (config.token) {
    headers['Authorization'] = `token ${config.token.trim()}`;
  }

  return axios.create({
    baseURL: `${normalizeUrl(config.url)}/api/v1`,
    headers,
    timeout: 10000,
  });
}

/**
 * Tests the connection to the Gitea/Forgejo instance and validates that the repository exists.
 * Returns the repository full name on success.
 */
export async function validateConnection(config: Config): Promise<string> {
  const client = createAxiosInstance(config);
  try {
    const response = await client.get(`/repos/${config.owner}/${config.repo}`);
    return response.data.full_name || `${config.owner}/${config.repo}`;
  } catch (error: any) {
    if (error.response) {
      if (error.response.status === 401) {
        throw new Error('Unauthorized: Invalid API Token or authentication failed.');
      }
      if (error.response.status === 404) {
        throw new Error(`Repository "${config.owner}/${config.repo}" not found or is private.`);
      }
      throw new Error(`API Error: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Failed to connect to ${config.url}: ${error.message}`);
  }
}

/**
 * Fetches a page of issues for a specific repository.
 */
export async function fetchIssues(
  config: Config,
  options: {
    page: number;
    limit: number;
    state: 'open' | 'closed' | 'all';
    type: 'issues' | 'pulls' | 'all';
    q: string;
    sortField: 'created' | 'updated' | 'comments';
    sortOrder: 'asc' | 'desc';
  }
): Promise<{ issues: Issue[]; totalCount: number }> {
  const client = createAxiosInstance(config);
  
  // Map our internal sort fields to Gitea API sort parameters
  let sort = 'newest';
  if (options.sortField === 'created') {
    sort = options.sortOrder === 'asc' ? 'oldest' : 'newest';
  } else if (options.sortField === 'updated') {
    sort = options.sortOrder === 'asc' ? 'leastupdate' : 'recentupdate';
  } else if (options.sortField === 'comments') {
    sort = options.sortOrder === 'asc' ? 'leastcomment' : 'mostcomment';
  }

  const params: Record<string, any> = {
    page: options.page,
    limit: options.limit,
    state: options.state,
    sort: sort,
  };

  // Filter by type: pulls or issues
  if (options.type !== 'all') {
    params.type = options.type;
  }

  // Filter by search query if present
  if (options.q.trim()) {
    params.q = options.q.trim();
  }

  try {
    const response = await client.get(`/repos/${config.owner}/${config.repo}/issues`, { params });
    
    // Parse x-total-count header
    const totalCountHeader = response.headers['x-total-count'];
    const totalCount = totalCountHeader ? parseInt(totalCountHeader, 10) : response.data.length;

    const issues: Issue[] = response.data.map((item: any) => ({
      id: item.id,
      number: item.number,
      title: item.title,
      state: item.state,
      body: item.body || '',
      user: {
        id: item.user?.id || 0,
        login: item.user?.login || 'unknown',
        full_name: item.user?.full_name || '',
      },
      created_at: item.created_at,
      updated_at: item.updated_at,
      comments: item.comments_count || item.comments || 0,
      labels: (item.labels || []).map((l: any) => ({
        id: l.id,
        name: l.name,
        color: l.color,
      })),
      pull_request: item.pull_request,
    }));

    return { issues, totalCount };
  } catch (error: any) {
    if (error.response) {
      throw new Error(`API Error: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Network Error: ${error.message}`);
  }
}

/**
 * Fetches a single issue by number.
 */
export async function fetchIssue(
  config: Config,
  issueNumber: number
): Promise<Issue> {
  const client = createAxiosInstance(config);
  try {
    const response = await client.get(`/repos/${config.owner}/${config.repo}/issues/${issueNumber}`);
    const item = response.data;
    return {
      id: item.id,
      number: item.number,
      title: item.title,
      state: item.state,
      body: item.body || '',
      user: {
        id: item.user?.id || 0,
        login: item.user?.login || 'unknown',
        full_name: item.user?.full_name || '',
      },
      created_at: item.created_at,
      updated_at: item.updated_at,
      comments: item.comments_count || item.comments || 0,
      labels: (item.labels || []).map((l: any) => ({
        id: l.id,
        name: l.name,
        color: l.color,
      })),
      pull_request: item.pull_request,
    };
  } catch (error: any) {
    if (error.response) {
      if (error.response.status === 401) {
        throw new Error('Unauthorized: Please check your token.');
      }
      throw new Error(`Failed to fetch issue: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Network Error: ${error.message}`);
  }
}

/**
 * Fetches comments for a specific issue.
 */
export async function fetchIssueComments(
  config: Config,
  issueNumber: number
): Promise<Comment[]> {
  const client = createAxiosInstance(config);
  try {
    const response = await client.get(`/repos/${config.owner}/${config.repo}/issues/${issueNumber}/comments`);
    
    const comments: Comment[] = response.data.map((item: any) => ({
      id: item.id,
      user: {
        id: item.user?.id || 0,
        login: item.user?.login || 'unknown',
        full_name: item.user?.full_name || '',
      },
      body: item.body || '',
      created_at: item.created_at,
      updated_at: item.updated_at,
    }));

    return comments;
  } catch (error: any) {
    if (error.response) {
      throw new Error(`Failed to fetch comments: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Network Error: ${error.message}`);
  }
}

/**
 * Validates connection and fetches all repositories accessible by the user.
 */
export async function authenticateAndFetchRepos(
  url: string,
  userid: string,
  token: string
): Promise<RepoItem[]> {
  const normalized = normalizeUrl(url);
  const headers: Record<string, string> = {
    'Accept': 'application/json',
    'Content-Type': 'application/json',
  };

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

  const client = axios.create({
    baseURL: `${normalized}/api/v1`,
    headers,
    timeout: 10000,
  });

  // 1. Verify credentials / user existence
  try {
    if (token.trim()) {
      await client.get('/user');
    } else if (userid.trim()) {
      await client.get(`/users/${userid.trim()}`);
    }
  } catch (error: any) {
    if (error.response) {
      if (error.response.status === 401) {
        throw new Error('Unauthorized: Invalid API Token.');
      }
      if (error.response.status === 404) {
        throw new Error(`User "${userid}" not found.`);
      }
      throw new Error(`Authentication failed: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Failed to connect to ${normalized}: ${error.message}`);
  }

  // 2. Fetch repositories
  try {
    let repos: any[] = [];
    
    if (token.trim()) {
      // Fetch authenticated user's repos (lists all they have access to)
      const response = await client.get('/user/repos', { params: { limit: 100 } });
      repos = response.data;
    } else if (userid.trim()) {
      // Fetch public repos of the target username
      const response = await client.get(`/users/${userid.trim()}/repos`, { params: { limit: 100 } });
      repos = response.data;
    }

    if (!Array.isArray(repos)) {
      throw new Error('Invalid response from server (expected list of repositories).');
    }

    return repos.map((r: any) => ({
      id: r.id,
      name: r.name,
      full_name: r.full_name || `${r.owner?.login}/${r.name}`,
      private: !!r.private,
      description: r.description || '',
    }));
  } catch (error: any) {
    if (error.response) {
      throw new Error(`Failed to fetch repositories: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Failed to fetch repositories: ${error.message}`);
  }
}

/**
 * Creates a new issue in the specified repository.
 */
export async function createIssue(
  config: Config,
  title: string,
  body: string
): Promise<Issue> {
  const client = createAxiosInstance(config);
  try {
    const response = await client.post(`/repos/${config.owner}/${config.repo}/issues`, {
      title,
      body,
    });
    
    const item = response.data;
    return {
      id: item.id,
      number: item.number,
      title: item.title,
      state: item.state,
      body: item.body || '',
      user: {
        id: item.user?.id || 0,
        login: item.user?.login || 'unknown',
        full_name: item.user?.full_name || '',
      },
      created_at: item.created_at,
      updated_at: item.updated_at,
      comments: item.comments_count || item.comments || 0,
      labels: (item.labels || []).map((l: any) => ({
        id: l.id,
        name: l.name,
        color: l.color,
      })),
      pull_request: item.pull_request,
    };
  } catch (error: any) {
    if (error.response) {
      if (error.response.status === 401) {
        throw new Error('Unauthorized: You must be logged in with a token to create an issue.');
      }
      throw new Error(`Failed to create issue: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Network Error: ${error.message}`);
  }
}

/**
 * Creates a comment on a specific issue.
 */
export async function createIssueComment(
  config: Config,
  issueNumber: number,
  body: string
): Promise<Comment> {
  const client = createAxiosInstance(config);
  try {
    const response = await client.post(`/repos/${config.owner}/${config.repo}/issues/${issueNumber}/comments`, {
      body,
    });
    
    const item = response.data;
    return {
      id: item.id,
      user: {
        id: item.user?.id || 0,
        login: item.user?.login || 'unknown',
        full_name: item.user?.full_name || '',
      },
      body: item.body,
      created_at: item.created_at,
      updated_at: item.updated_at,
    };
  } catch (error: any) {
    if (error.response) {
      if (error.response.status === 401) {
        throw new Error('Unauthorized: You must be logged in with a token to comment.');
      }
      throw new Error(`Failed to create comment: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Network Error: ${error.message}`);
  }
}

/**
 * Edits an existing issue.
 */
export async function editIssue(
  config: Config,
  issueNumber: number,
  title: string,
  body: string
): Promise<Issue> {
  const client = createAxiosInstance(config);
  try {
    const response = await client.patch(`/repos/${config.owner}/${config.repo}/issues/${issueNumber}`, {
      title,
      body,
    });
    
    const item = response.data;
    return {
      id: item.id,
      number: item.number,
      title: item.title,
      state: item.state,
      body: item.body || '',
      user: {
        id: item.user?.id || 0,
        login: item.user?.login || 'unknown',
        full_name: item.user?.full_name || '',
      },
      created_at: item.created_at,
      updated_at: item.updated_at,
      comments: item.comments_count || item.comments || 0,
      labels: (item.labels || []).map((l: any) => ({
        id: l.id,
        name: l.name,
        color: l.color,
      })),
      pull_request: item.pull_request,
    };
  } catch (error: any) {
    if (error.response) {
      if (error.response.status === 401) {
        throw new Error('Unauthorized: You must be logged in with a token to edit an issue.');
      }
      throw new Error(`Failed to edit issue: ${error.response.data?.message || error.message}`);
    }
    throw new Error(`Network Error: ${error.message}`);
  }
}