import { KnowledgeSource, RetrievedChunk, Citation, Language, LegalQueryResponse, ImageJob } from './types';

const DEFAULT_API_BASE = 'http://127.0.0.1:8000';
const API_BASE = (import.meta as any).env?.VITE_API_URL || DEFAULT_API_BASE;

// ── Types ────────────────────────────────────────────────────────────────────

type BackendSource = {
  id: string;
  type: 'pdf' | 'url' | 'youtube' | 'statute' | 'judgment' | 'constitution';
  title: string;
  origin?: string;
  language?: string;
  status?: KnowledgeSource['status'];
  chunkCount?: number;
  createdAt?: string;
  dateAdded?: string;
  doc_type?: string;   // For legal sources
  court?: string;      // For legal sources
  judgment_date?: string; // For legal sources
  progress_percentage?: number;
  error_message?: string;
};

export interface QueryResponse {
  answer: string;
  sources: Citation[];
  retrievedChunks: RetrievedChunk[];
  conversationId?: string; // Added for Phase 1
}

export interface Conversation {
  id: string;
  title: string;
  conv_type?: 'general' | 'legal';
  created_at: string;
  updated_at: string;
  message_count: number;
}

export interface ConversationMessage {
  id: string;
  question: string;
  answer: string;
  sourcesUsed: string[];
  createdAt: string;
}

// ── Helper: Normalization ───────────────────────────────────────────────────

function normalizeSource(raw: BackendSource): KnowledgeSource {
  // Map "url" → "web" for frontend type consistency
  let type: KnowledgeSource['type'] =
    raw.type === 'url' ? 'web' :
      (raw.type as KnowledgeSource['type']);

  // If it's a legal type from Prompt 4, we might want to map it to 'pdf' 
  // or keep it if types.ts supports it. Assuming pdf for now if not 'web'/'youtube'.
  if (['statute', 'judgment', 'constitution'].includes(raw.type)) {
    type = 'pdf';
  }

  const language = ((raw.language || 'en').toUpperCase()) as Language;
  const dateRaw = raw.createdAt || raw.dateAdded;
  const dateAdded = dateRaw ? new Date(dateRaw) : new Date();

  const metadata: KnowledgeSource['metadata'] = {};
  if (raw.origin) {
    if (type === 'web' || type === 'youtube') metadata.url = raw.origin;
    if (raw.origin.match(/[?&]v=([^&]+)/)) {
      const match = raw.origin.match(/[?&]v=([^&]+)/);
      if (match) metadata.videoId = match[1];
    }
  }

  // Add legal metadata if present
  if (raw.doc_type) metadata.docType = raw.doc_type;
  if (raw.court) metadata.court = raw.court;
  if (raw.judgment_date) metadata.judgmentDate = raw.judgment_date;

  return {
    id: String(raw.id),
    type: type || 'pdf',
    title: raw.title,
    language,
    status: raw.status || 'completed',
    chunkCount: raw.chunkCount ?? 0,
    dateAdded,
    progress_percentage: raw.progress_percentage ?? 0,
    error_message: raw.error_message,
    metadata,
  };
}

// ── Sources API ──────────────────────────────────────────────────────────────

export async function fetchSources(): Promise<KnowledgeSource[]> {
  const res = await fetch(`${API_BASE}/sources`);
  if (!res.ok) throw new Error(`Failed to fetch sources: ${res.statusText}`);
  const data = await res.json();
  const raw: BackendSource[] = Array.isArray(data) ? data : (data.sources ?? []);
  return raw.map(normalizeSource);
}

export async function fetchLegalSources(): Promise<KnowledgeSource[]> {
  const res = await fetch(`${API_BASE}/legal/legal-sources`);
  if (!res.ok) throw new Error(`Failed to fetch legal sources: ${res.statusText}`);
  const data = await res.json();
  const raw: BackendSource[] = data.sources ?? [];
  return raw.map(normalizeSource);
}

export async function deleteSource(id: string): Promise<void> {
  const res = await fetch(`${API_BASE}/sources/${encodeURIComponent(id)}`, {
    method: 'DELETE',
  });
  if (!res.ok) {
    const detail = await res.text().catch(() => '');
    throw new Error(detail || `Delete failed with status ${res.status}`);
  }
}

// ── Ingestion API ────────────────────────────────────────────────────────────

export async function uploadPdf(file: File): Promise<KnowledgeSource> {
  const formData = new FormData();
  formData.append('file', file);

  const res = await fetch(`${API_BASE}/upload-pdf`, {
    method: 'POST',
    body: formData,
  });

  if (!res.ok) throw new Error(await res.text() || 'PDF Upload failed');
  const data = await res.json();
  return normalizeSource({
    id: data.source_id,
    type: 'pdf',
    title: data.title,
    chunkCount: data.chunk_count,
    status: data.status || 'UPLOADING',
    createdAt: new Date().toISOString(),
  });
}

export async function fetchSourceProgress(sourceId: string): Promise<KnowledgeSource & { progress_percentage: number; error_message?: string }> {
  const res = await fetch(`${API_BASE}/sources/${encodeURIComponent(sourceId)}`);
  if (!res.ok) throw new Error(`Failed to fetch source progress: ${res.statusText}`);
  const data = await res.json();
  return {
    ...normalizeSource(data),
    progress_percentage: data.progress_percentage ?? 0,
    error_message: data.error_message,
  };
}

export async function uploadLegal(file: File, docType: string = "judgment"): Promise<KnowledgeSource> {
  const formData = new FormData();
  formData.append('file', file);

  const res = await fetch(`${API_BASE}/legal/upload-legal?doc_type=${docType}`, {
    method: 'POST',
    body: formData,
  });

  if (!res.ok) throw new Error(await res.text() || 'Legal Upload failed');
  const data = await res.json();
  return normalizeSource({
    id: data.source_id,
    type: data.doc_type as any || 'pdf',
    title: data.title,
    chunkCount: data.chunk_count,
    status: 'completed',
    createdAt: new Date().toISOString(),
    doc_type: data.doc_type
  });
}

export async function addWebsite(url: string, language: Language = 'EN'): Promise<KnowledgeSource> {
  const res = await fetch(`${API_BASE}/add-url`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ url, language: language.toLowerCase() }),
  });
  if (!res.ok) throw new Error(await res.text() || 'URL Ingestion failed');
  const data = await res.json();
  return normalizeSource({
    id: data.source_id,
    type: 'url',
    title: data.title,
    chunkCount: data.chunk_count,
    status: data.status || 'EXTRACTING',
    origin: url,
  });
}

export async function addYouTube(url: string, language: Language = 'EN'): Promise<KnowledgeSource> {
  const res = await fetch(`${API_BASE}/add-youtube`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ url, language: language.toLowerCase() }),
  });
  if (!res.ok) throw new Error(await res.text() || 'YouTube Ingestion failed');
  const data = await res.json();
  return normalizeSource({
    id: data.source_id,
    type: 'youtube',
    title: data.title,
    chunkCount: data.chunk_count,
    status: data.status || 'EXTRACTING',
    origin: url,
  });
}

// ── Image API ────────────────────────────────────────────────────────────────

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

  const res = await fetch(`${API_BASE}/images/upload-image`, {
    method: 'POST',
    body: formData,
  });

  if (!res.ok) throw new Error(await res.text() || 'Image Upload failed');
  return await res.json();
}

export async function fetchImageJobs(): Promise<ImageJob[]> {
  const res = await fetch(`${API_BASE}/images/image-jobs`);
  if (!res.ok) throw new Error(`Failed to fetch image jobs: ${res.statusText}`);
  const data = await res.json();
  return data.jobs ?? [];
}

export async function fetchPendingImageCount(): Promise<number> {
  const res = await fetch(`${API_BASE}/images/image-jobs/pending-count`);
  if (!res.ok) throw new Error(`Failed to fetch pending count: ${res.statusText}`);
  const data = await res.json();
  return data.count ?? 0;
}

// ── Query API ───────────────────────────────────────────────────────────────

export async function queryRag(
  question: string, 
  sourceIds?: string[], 
  imageId?: string, 
  includeImages?: boolean,
  llmProvider: string = "groq"
): Promise<QueryResponse> {
  const res = await fetch(`${API_BASE}/query`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      question,
      source_ids: sourceIds && sourceIds.length > 0 ? sourceIds : null,
      conversation_id: (window as any).currentConversationId || null,
      image_id: imageId || null,
      include_images: includeImages || false,
      llm_provider: llmProvider,
    }),
  });

  if (!res.ok) throw new Error(await res.text() || 'Query failed');
  const data = await res.json();

  return {
    answer: data.answer,
    conversationId: data.conversationId, // Added for Phase 1
    sources: (data.citations || []).map((c: any) => ({
      sourceTitle: c.sourceTitle || c.source_title || '',
      sourceType: c.sourceType === 'url' ? 'web' : (c.sourceType || 'pdf'),
      reference: c.reference || '',
      snippet: c.snippet || '',
    })),
    retrievedChunks: (data.retrievedChunks || []).map((c: any) => ({
      id: c.chunkId || c.id || '',
      sourceId: c.sourceId || '',
      sourceName: c.sourceTitle || c.sourceName || '',
      sourceType: c.sourceType === 'url' ? 'web' : (c.sourceType || 'pdf'),
      language: ((c.language || 'en').toUpperCase()) as Language,
      text: c.text || '',
      similarityScore: c.score ?? c.similarityScore ?? 0,
      metadata: {
        page: c.pageNumber ?? c.metadata?.page,
        timestamp: c.timestampS != null
          ? `${Math.floor(c.timestampS / 60)}:${String(c.timestampS % 60).padStart(2, '0')}`
          : c.metadata?.timestamp,
        url: c.urlRef || c.metadata?.url,
        ipcSections: c.metadata?.ipc_sections || c.ipc_sections || [],
      },
    })),
  };
}

// ── Streaming API ───────────────────────────────────────────────────────────

export async function streamQueryRag(
  question: string,
  sourceIds: string[] | undefined,
  history: Array<{ role: string; content: string }>,
  onToken: (token: string) => void,
  onMeta: (meta: { chatId: string; conversationId?: string; citations: Citation[]; retrievedChunks: RetrievedChunk[] }) => void,
  onError: (err: Error) => void,
  imageId?: string,
  includeImages?: boolean,
  llmProvider: string = "groq",
  isLegalMode: boolean = false,
  legalFilter: string | null = null,
  agenticMode: boolean = false,
  onAgentStatus?: (status: { stage: number; message: string }) => void
): Promise<void> {
  let response: Response;
  try {
    response = await fetch(`${API_BASE}/query-stream`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        question,
        source_ids: sourceIds && sourceIds.length > 0 ? sourceIds : null,
        history,
        conversation_id: (window as any).currentConversationId || null,
        image_id: imageId || null,
        include_images: includeImages || false,
        llm_provider: llmProvider,
        is_legal_mode: isLegalMode,
        legal_filter: legalFilter,
        agentic_mode: agenticMode,
      }),
    });
  } catch (err) {
    if (err instanceof TypeError && err.message.includes('fetch')) {
      onError(new Error("Cannot connect to server. Is the backend running on port 8000?"));
    } else {
      onError(err instanceof Error ? err : new Error(String(err)));
    }
    return;
  }

  if (!response.ok) {
    onError(new Error(`Server returned ${response.status}`));
    return;
  }
  if (!response.body) {
    onError(new Error('No response body from server'));
    return;
  }

  const reader = response.body.getReader();
  const decoder = new TextDecoder();
  let buffer = '';

  try {
    while (true) {
      const { done, value } = await reader.read();
      if (done) break;

      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split('\n');
      buffer = lines.pop() || '';

      for (const line of lines) {
        if (!line.startsWith('data: ')) continue;
        const jsonStr = line.slice(6).trim();
        if (!jsonStr) continue;

        try {
          const parsed = JSON.parse(jsonStr);

          if (parsed.type === 'error') {
            onError(new Error(parsed.message || "Unknown streaming error"));
            return;
          }

          if (parsed.type === 'agent_status') {
            if (onAgentStatus) {
              onAgentStatus({ stage: parsed.stage, message: parsed.message });
            }
          }

          if (parsed.type === 'meta') {
            const citations: Citation[] = (parsed.citations || []).map((c: any) => ({
              sourceTitle: c.sourceTitle || c.source_title || '',
              sourceType: (c.sourceType === 'url' ? 'web' : c.sourceType || 'pdf') as any,
              reference: c.reference || '',
              snippet: c.snippet || '',
            }));

            const retrievedChunks: RetrievedChunk[] = (parsed.retrievedChunks || []).map((c: any, i: number) => ({
              id: c.chunkId || String(i),
              sourceId: c.sourceId || '',
              sourceName: c.sourceTitle || '',
              sourceType: (c.sourceType === 'url' ? 'web' : c.sourceType || 'pdf') as any,
              text: c.text || '',
              similarityScore: c.score || 0,
              metadata: { page: c.pageNumber, timestamp: c.timestampS, url: c.urlRef }
            }));

            onMeta({ 
              chatId: parsed.chatId || '', 
              conversationId: parsed.conversationId, 
              citations, 
              retrievedChunks 
            });
          }

          if (parsed.type === 'token' && parsed.content) {
            onToken(parsed.content);
          }

          if (parsed.type === 'done') {
            return;
          }
        } catch (e) {
          // Partial JSON or parse error — skip
        }
      }
    }
  } catch (err) {
    onError(err instanceof Error ? err : new Error(String(err)));
  }
}

// ── Evaluation API ───────────────────────────────────────────────────────────

export async function startEvaluation(nQuestions: number = 15, agenticMode: boolean = false): Promise<string> {
  const response = await fetch(`${API_BASE}/eval/start`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ 
      n_questions: nQuestions,
      agentic_mode: agenticMode
    }),
  });
  if (!response.ok) {
    const error = await response.json();
    throw new Error(error.detail || 'Failed to start evaluation');
  }
  const data = await response.json();
  return data.job_id;
}

export async function getEvaluationStatus(jobId: string): Promise<any> {
  const response = await fetch(`${API_BASE}/eval/status/${jobId}`);
  if (!response.ok) {
    throw new Error('Failed to fetch evaluation status');
  }
  return response.json();
}

// ── History API ─────────────────────────────────────────────────────────────

export interface BackendChatEntry {
  id: string;
  question: string;
  answer: string;
  sourcesUsed: string[];
  createdAt: string;
}

export async function fetchHistory(): Promise<BackendChatEntry[]> {
  const res = await fetch(`${API_BASE}/history`);
  if (!res.ok) throw new Error(`Failed to fetch history: ${res.statusText}`);
  const data = await res.json();
  return data.history ?? [];
}

export async function clearHistory(): Promise<void> {
  const res = await fetch(`${API_BASE}/history`, { method: 'DELETE' });
  if (!res.ok) throw new Error('Failed to clear history');
}

// ── Events ──────────────────────────────────────────────────────────────────

export function notifySidebarRefresh() {
  window.dispatchEvent(new CustomEvent('sources-updated'));
}

export async function queryLegal(question: string, sourceFilter?: string, modelType: "finetuned" | "base" = "finetuned"): Promise<LegalQueryResponse> {
  const res = await fetch(`${API_BASE}/legal-query`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ 
      question, 
      source_filter: sourceFilter || null, 
      language: "en",
      model_type: modelType 
    })
  });
  if (!res.ok) {
    const text = await res.text();
    throw new Error(`Failed to query legal search: ${text}`);
  }
  return res.json();
}

// ── Conversations API ────────────────────────────────────────────────────────

export async function createConversation(title = 'New Chat'): Promise<Conversation> {
  const res = await fetch(`${API_BASE}/conversations`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ title }),
  });
  if (!res.ok) throw new Error('Failed to create conversation');
  return res.json();
}

export async function fetchConversations(): Promise<Conversation[]> {
  const res = await fetch(`${API_BASE}/conversations`);
  if (!res.ok) throw new Error('Failed to fetch conversations');
  const data = await res.json();
  return data.conversations ?? [];
}

export async function fetchConversationMessages(convId: string): Promise<{
  conversation: { id: string; title: string };
  messages: ConversationMessage[];
}> {
  const res = await fetch(`${API_BASE}/conversations/${convId}/messages`);
  if (!res.ok) throw new Error('Failed to fetch messages');
  return res.json();
}

export async function renameConversation(convId: string, title: string): Promise<void> {
  await fetch(`${API_BASE}/conversations/${convId}`, {
    method: 'PATCH',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ title }),
  });
}

export async function deleteConversation(convId: string): Promise<void> {
  await fetch(`${API_BASE}/conversations/${convId}`, { method: 'DELETE' });
}

// ── Export API ──────────────────────────────────────────────────────────────

export async function exportToPDF(title: string, content: string, citations: any[]): Promise<void> {
  const response = await fetch(`${API_BASE}/export/pdf`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ title, content, citations }),
  });

  if (!response.ok) throw new Error('Failed to export PDF');

  const blob = await response.blob();
  const url = window.URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = `InteleX_Research_${new Date().getTime()}.pdf`;
  document.body.appendChild(a);
  a.click();
  window.URL.revokeObjectURL(url);
  document.body.removeChild(a);
}