import type { 
  VideoStatusResponse, 
  SegmentsPayload,
  HealthStatus,
  ExtractedFrame,
  LoginRequest,
  LoginResponse,
  AuthUser
} from '@/types';

const API_BASE = import.meta.env.VITE_API_BASE_URL || 'http://localhost:4000';

// Get auth token from localStorage
function getAuthToken(): string | null {
  return localStorage.getItem('auth_token');
}

// Set auth token in localStorage
export function setAuthToken(token: string): void {
  localStorage.setItem('auth_token', token);
}

// Remove auth token from localStorage
export function removeAuthToken(): void {
  localStorage.removeItem('auth_token');
}

// Generic API request handler
async function apiRequest<T>(
  path: string, 
  options: RequestInit = {}
): Promise<T> {
  const url = path.startsWith('http') ? path : `${API_BASE}${path}`;
  const token = getAuthToken();
  
  // Normalize headers to a plain object
  const headers: Record<string, string> = {};
  
  // Convert Headers object or array to plain object
  if (options.headers) {
    if (options.headers instanceof Headers) {
      options.headers.forEach((value, key) => {
        headers[key] = value;
      });
    } else if (Array.isArray(options.headers)) {
      options.headers.forEach(([key, value]) => {
        headers[key] = value;
      });
    } else {
      Object.assign(headers, options.headers);
    }
  }
  
  // Add auth token if available
  if (token) {
    headers['Authorization'] = `Bearer ${token}`;
  }
  
  const response = await fetch(url, {
    ...options,
    headers,
  });

  if (!response.ok) {
    // If unauthorized, clear token
    if (response.status === 401) {
      removeAuthToken();
    }
    
    let errorMessage = `Request failed with status ${response.status}`;
    
    // Try to extract error message from response
    const contentType = response.headers.get('content-type');
    const isJson = contentType && contentType.includes('application/json');
    
    try {
      if (isJson) {
      const errorData = await response.json();
        // Try multiple common error message fields
        errorMessage = errorData.detail || 
                       errorData.message || 
                       errorData.error || 
                       (typeof errorData === 'string' ? errorData : errorMessage);
      } else {
        const text = await response.text();
        if (text && text.trim()) {
          errorMessage = text;
        } else {
          // Fall back to default message based on status code
          if (response.status === 401) {
            errorMessage = 'Incorrect username or password.';
          } else if (response.status === 403) {
            errorMessage = 'Access forbidden.';
          } else if (response.status === 404) {
            errorMessage = 'Resource not found.';
          } else if (response.status >= 500) {
            errorMessage = 'Server error. Please try again later.';
          }
        }
      }
    } catch (parseError) {
      // If parsing fails, use status-based default
      if (response.status === 401) {
        errorMessage = 'Incorrect username or password.';
      } else if (response.status === 403) {
        errorMessage = 'Access forbidden.';
      } else if (response.status === 404) {
        errorMessage = 'Resource not found.';
      } else if (response.status >= 500) {
        errorMessage = 'Server error. Please try again later.';
      }
    }
    
    const error = new Error(errorMessage);
    console.error('API Error:', {
      status: response.status,
      statusText: response.statusText,
      message: errorMessage,
      url: url,
      contentType: contentType
    });
    throw error;
  }

  return response.json();
}

// Health check
export async function checkHealth(): Promise<HealthStatus> {
  return apiRequest<HealthStatus>('/health');
}

// ==================== AUTHENTICATION ====================

export async function login(credentials: LoginRequest): Promise<LoginResponse> {
  const response = await apiRequest<LoginResponse>('/api/auth/login', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(credentials),
  });
  
  // Store token
  if (response.access_token) {
    setAuthToken(response.access_token);
  }
  
  return response;
}

export async function verifyAuth(): Promise<AuthUser> {
  try {
    const response = await apiRequest<AuthUser>('/api/auth/verify');
    return response;
  } catch {
    removeAuthToken();
    return { username: '', authenticated: false };
  }
}

export async function getCurrentUser(): Promise<AuthUser> {
  try {
    const response = await apiRequest<AuthUser>('/api/auth/me');
    return response;
  } catch {
    removeAuthToken();
    return { username: '', authenticated: false };
  }
}

export function logout(): void {
  removeAuthToken();
}

// ==================== KLING/KIE API ====================

export interface KlingGenerateParams {
  prompt: string | object;
  imageUrls?: string[];
  model?: string;
  aspectRatio?: string;
  generationType?: string;
  seeds?: number;
  voiceType?: string;
}

export interface KlingGenerateResponse {
  taskId: string;
  status: string;
}

export async function klingGenerate(params: KlingGenerateParams): Promise<KlingGenerateResponse> {
  return apiRequest<KlingGenerateResponse>('/api/veo/generate', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(params),
  });
}

export async function klingExtend(taskId: string, prompt: string | object, seeds?: number, voiceType?: string): Promise<KlingGenerateResponse> {
  return apiRequest<KlingGenerateResponse>('/api/veo/extend', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ taskId, prompt, seeds, voiceType }),
  });
}

export async function klingGetStatus(taskId: string): Promise<VideoStatusResponse> {
  return apiRequest<VideoStatusResponse>(`/api/veo/status/${taskId}`);
}

export async function klingCancel(taskId: string): Promise<{ code: number; msg: string; taskId: string }> {
  return apiRequest<{ code: number; msg: string; taskId: string }>(`/api/veo/cancel/${taskId}`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
  });
}

export function createKlingEventSource(taskId: string): EventSource {
  return new EventSource(`${API_BASE}/api/veo/events/${taskId}`);
}

// ==================== REPLICATE API ====================

export interface ReplicateGenerateParams {
  prompt: string;
  imageUrl?: string;
  model?: string;
  duration?: number;
  aspectRatio?: string;
}

export interface ReplicateGenerateResponse {
  id: string;
  status: string;
}

export async function replicateGenerate(params: ReplicateGenerateParams): Promise<ReplicateGenerateResponse> {
  return apiRequest<ReplicateGenerateResponse>('/api/replicate/generate', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(params),
  });
}

export async function replicateGetStatus(predictionId: string): Promise<VideoStatusResponse> {
  return apiRequest<VideoStatusResponse>(`/api/replicate/status/${predictionId}`);
}

// Wait for Replicate video completion by polling
export async function waitForReplicateVideo(
  predictionId: string, 
  timeoutMs: number = 600000, // 10 minutes
  pollIntervalMs: number = 15000 // Poll every 15 seconds (video gen takes 2-5 min)
): Promise<string> {
  const startTime = Date.now();
  
  while (Date.now() - startTime < timeoutMs) {
    const status = await replicateGetStatus(predictionId);
    
    if (status.status === 'succeeded' && status.url) {
      return status.url;
    } else if (status.status === 'failed') {
      throw new Error(status.error || 'Replicate video generation failed');
    }
    
    // Wait before next poll
    await new Promise(resolve => setTimeout(resolve, pollIntervalMs));
  }
  
  throw new Error('Replicate video generation timed out');
}

// ==================== PROMPT GENERATION ====================

export async function generatePrompts(formData: FormData): Promise<SegmentsPayload> {
  const response = await fetch(`${API_BASE}/api/generate-prompts`, {
    method: 'POST',
    body: formData,
  });

  if (!response.ok) {
    let errorMessage = 'Failed to generate prompts';
    try {
      const errorData = await response.json();
      errorMessage = errorData.detail || errorMessage;
    } catch {
      // Ignore
    }
    throw new Error(errorMessage);
  }

  return response.json();
}

export async function refinePromptContinuity(
  segmentPrompt: object, 
  lastFrameBlob: Blob
): Promise<{ refined_prompt: object }> {
  const formData = new FormData();
  formData.append('segmentPrompt', JSON.stringify(segmentPrompt));
  formData.append('lastFrame', lastFrameBlob, 'last-frame.jpg');

  return apiRequest<{ refined_prompt: object }>('/api/refine-prompt-continuity', {
    method: 'POST',
    body: formData,
  });
}

// ==================== IMAGE UPLOAD ====================

export async function uploadImage(file: File): Promise<{ url: string; filename: string }> {
  const formData = new FormData();
  formData.append('file', file);

  return apiRequest<{ url: string; filename: string }>('/api/upload-image', {
    method: 'POST',
    body: formData,
  });
}

// ==================== FRAME EXTRACTION ====================

export interface ExtractFramesParams {
  video_url: string;
  script?: string;
  buffer_time?: number;
  num_frames?: number;
  model_size?: string;
}

export interface ExtractFramesResponse {
  frames: ExtractedFrame[];
}

export async function extractFrames(params: ExtractFramesParams): Promise<ExtractFramesResponse> {
  return apiRequest<ExtractFramesResponse>('/api/extract-frames', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(params),
  });
}

// ==================== WHISPER ANALYSIS ====================

export interface WhisperAnalyzeParams {
  video_url: string;
  dialogue: string;
  buffer_time?: number;
  model_size?: string;
}

export interface WhisperAnalyzeResponse {
  success: boolean;
  last_word_timestamp: number | null;
  trim_point: number | null;
  frame_timestamp: number | null;
  frame_base64: string | null;
  video_duration: number;
  transcribed_text: string | null;  // What Whisper actually heard - for prompt refinement
  error: string | null;
}

/**
 * Analyze video with Whisper to find last spoken word and extract frame.
 * This is the optimized flow that combines Whisper analysis and frame extraction.
 */
export async function whisperAnalyzeAndExtract(params: WhisperAnalyzeParams): Promise<WhisperAnalyzeResponse> {
  return apiRequest<WhisperAnalyzeResponse>('/api/whisper/analyze-and-extract', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(params),
  });
}

/**
 * Refine a segment prompt using the frame AND transcription from the previous segment.
 * This ensures perfect visual and audio continuity.
 */
export async function refinePromptWithContext(
  segmentPrompt: object,
  frameFile: File,
  transcribedDialogue: string,
  expectedDialogue: string
): Promise<{ refined_prompt: object; original_prompt: object }> {
  const formData = new FormData();
  formData.append('segmentPrompt', JSON.stringify(segmentPrompt));
  formData.append('lastFrame', frameFile);
  formData.append('transcribedDialogue', transcribedDialogue);
  formData.append('expectedDialogue', expectedDialogue);
  
  const response = await fetch(`${API_BASE}/api/refine-prompt-continuity`, {
    method: 'POST',
    body: formData,
  });
  
  if (!response.ok) {
    throw new Error(`Failed to refine prompt: ${response.status}`);
  }
  
  return response.json();
}

/**
 * Check if Whisper is available on the backend
 */
export async function checkWhisperStatus(): Promise<{ available: boolean; message: string }> {
  return apiRequest<{ available: boolean; message: string }>('/api/whisper/status');
}

// ==================== VIDEO DOWNLOAD ====================

export async function downloadVideo(url: string): Promise<Blob> {
  const response = await fetch(`${API_BASE}/api/veo/download?url=${encodeURIComponent(url)}`);
  
  if (!response.ok) {
    throw new Error(`Failed to download video: ${response.status}`);
  }

  return response.blob();
}

// ==================== UTILITIES ====================

export async function getVideoDuration(file: File): Promise<number> {
  return new Promise((resolve, reject) => {
    const video = document.createElement('video');
    video.preload = 'metadata';
    video.src = URL.createObjectURL(file);
    video.onloadedmetadata = () => {
      URL.revokeObjectURL(video.src);
      resolve(video.duration);
    };
    video.onerror = () => {
      URL.revokeObjectURL(video.src);
      reject(new Error('Failed to load video metadata'));
    };
  });
}

export async function generateThumbnails(file: File, count: number = 5): Promise<string[]> {
  return new Promise((resolve, reject) => {
    const video = document.createElement('video');
    video.preload = 'metadata';
    video.src = URL.createObjectURL(file);
    video.muted = true;

    video.onloadedmetadata = async () => {
      const duration = video.duration;
      const thumbnails: string[] = [];
      const canvas = document.createElement('canvas');
      const ctx = canvas.getContext('2d');

      if (!ctx) {
        URL.revokeObjectURL(video.src);
        reject(new Error('Could not get canvas context'));
        return;
      }

      // Use video's actual dimensions for proper aspect ratio
      // Scale down while maintaining aspect ratio (max 400px on longest side)
      const maxSize = 400;
      const videoWidth = video.videoWidth || 1080;
      const videoHeight = video.videoHeight || 1920;
      const scale = Math.min(maxSize / videoWidth, maxSize / videoHeight);
      
      canvas.width = Math.round(videoWidth * scale);
      canvas.height = Math.round(videoHeight * scale);

      for (let i = 0; i < count; i++) {
        const time = (duration / count) * i;
        video.currentTime = time;
        await new Promise<void>((res) => {
          video.onseeked = () => res();
        });
        ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
        thumbnails.push(canvas.toDataURL('image/jpeg', 0.85));
      }

      URL.revokeObjectURL(video.src);
      resolve(thumbnails);
    };

    video.onerror = () => {
      URL.revokeObjectURL(video.src);
      reject(new Error('Failed to load video'));
    };
  });
}

// Wait for video completion using SSE
export function waitForKlingVideo(taskId: string, timeoutMs: number = 300000): Promise<string> {
  return new Promise((resolve, reject) => {
    const eventSource = createKlingEventSource(taskId);
    const startTime = Date.now();

    const timeout = setTimeout(() => {
      eventSource.close();
      reject(new Error('Video generation timed out'));
    }, timeoutMs);

    eventSource.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        
        if (data.status === 'succeeded' && data.url) {
          clearTimeout(timeout);
          eventSource.close();
          resolve(data.url);
        } else if (data.status === 'cancelled') {
          clearTimeout(timeout);
          eventSource.close();
          reject(new Error('Video generation cancelled by user'));
        } else if (data.status === 'failed' || data.code !== undefined && data.code !== 200) {
          clearTimeout(timeout);
          eventSource.close();
          const errorMsg = data.error || data.msg || `Video generation failed (code: ${data.code || 'unknown'})`;
          reject(new Error(errorMsg));
        }
      } catch (err) {
        console.error('Failed to parse SSE data:', err);
        // If we can't parse, don't reject immediately - might be a partial message
      }
    };

    eventSource.onerror = () => {
      // If connection error and we've been waiting a while, reject
      const elapsed = Date.now() - startTime;
      if (elapsed > 5000) { // Wait at least 5 seconds before rejecting on connection error
        clearTimeout(timeout);
        eventSource.close();
        reject(new Error('SSE connection error - video generation may have failed'));
      }
    };
  });
}

// Generate video with automatic retry (retries once on failure)
export async function generateVideoWithRetry(
  generateFn: () => Promise<{ taskId: string }>,
  timeoutMs: number = 300000,
  onRetry?: (attempt: number) => void
): Promise<string> {
  let lastError: Error | null = null;
  
  for (let attempt = 0; attempt < 2; attempt++) {
    try {
      if (attempt > 0) {
        console.log(`🔄 Retrying video generation (attempt ${attempt + 1}/2)...`);
        if (onRetry) {
          onRetry(attempt + 1);
        }
      }
      
      const result = await generateFn();
      const videoUrl = await waitForKlingVideo(result.taskId, timeoutMs);
      return videoUrl;
    } catch (error) {
      lastError = error instanceof Error ? error : new Error(String(error));
      console.error(`❌ Video generation attempt ${attempt + 1} failed:`, lastError.message);
      
      // If this was the first attempt, retry once
      if (attempt === 0) {
        console.log('⏳ Waiting 2 seconds before retry...');
        await new Promise(resolve => setTimeout(resolve, 2000)); // Wait 2 seconds before retry
        continue;
      }
      
      // If both attempts failed, throw the error
      throw lastError;
    }
  }
  
  // This should never be reached, but TypeScript needs it
  throw lastError || new Error('Video generation failed');
}

// ==================== VIDEO MERGE/EXPORT ====================

export interface ClipMetadata {
  index: number;
  startTime: number;
  endTime: number;
  type: 'video' | 'image';
  duration?: number;
}

// Merge multiple video files into a single video
export async function mergeVideos(
  videoBlobs: Blob[],
  clipMetadata: ClipMetadata[]
): Promise<Blob> {
  const formData = new FormData();
  
  // Add clip metadata as JSON
  formData.append('clips_data', JSON.stringify(clipMetadata));
  
  // Add video files
  videoBlobs.forEach((blob, index) => {
    formData.append('files', blob, `video_${index}.mp4`);
  });
  
  const response = await fetch(`${API_BASE}/api/export/merge`, {
    method: 'POST',
    body: formData,
  });
  
  if (!response.ok) {
    let errorMessage = 'Failed to merge videos';
    try {
      const errorData = await response.json();
      errorMessage = errorData.detail || errorMessage;
    } catch {
      // Ignore JSON parse errors
    }
    throw new Error(errorMessage);
  }
  
  return response.blob();
}