// web/src/lib/api.ts

export type LearningMode = 'concept' | 'socratic' | 'exam' | 'assignment' | 'summary';
export type Language = 'auto' | 'en' | 'zh';
export type FileType = 'syllabus' | 'lecture-slides' | 'literature-review' | 'other';

export interface User {
  name: string;
  email: string; // use email as user_id
}

const modeMap: Record<LearningMode, string> = {
  concept: 'Concept Explainer',
  socratic: 'Socratic Tutor',
  exam: 'Exam Prep / Quiz',
  assignment: 'Assignment Helper',
  summary: 'Quick Summary',
};

const langMap: Record<Language, string> = {
  auto: 'Auto',
  en: 'English',
  zh: '简体中文',
};

const docTypeMap: Record<FileType, string> = {
  syllabus: 'Syllabus',
  'lecture-slides': 'Lecture Slides',
  'literature-review': 'Literature Review / Paper',
  other: 'Other',
};

async function mustJson<T>(res: Response): Promise<T> {
  if (res.ok) return (await res.json()) as T;
  const txt = await res.text().catch(() => '');
  throw new Error(`${res.status} ${res.statusText}${txt ? ` — ${txt}` : ''}`);
}

// -----------------------------
// Helpers
// -----------------------------
function resolveDocType(docType?: FileType | string): string | undefined {
  if (!docType) return undefined;

  // If docType is one of FileType keys, map it; otherwise assume it's already backend-ready.
  const mapped = (docTypeMap as Record<string, string>)[docType];
  return mapped ?? docType;
}

// -----------------------------
// Core APIs
// -----------------------------
export async function apiLogin(user: User) {
  const res = await fetch('/api/login', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ name: user.name, user_id: user.email }),
  });
  return mustJson<{ ok: boolean; user: { name: string; user_id: string } }>(res);
}

export async function apiChat(params: {
  user: User;
  message: string;
  learningMode: LearningMode;
  language: Language;
  docType?: FileType | string; // optional override
}) {
  const res = await fetch('/api/chat', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      user_id: params.user.email,
      message: params.message,
      learning_mode: modeMap[params.learningMode],
      language_preference: langMap[params.language],
      doc_type: resolveDocType(params.docType) ?? 'Syllabus',
    }),
  });

  return mustJson<{
    reply: string;
    refs?: Array<{ source_file?: string; section?: string }>;
    latency_ms?: number;
    session_status_md?: string;
  }>(res);
}

export async function apiUpload(params: {
  user: User;
  file: File;
  fileType: FileType;
}) {
  const fd = new FormData();
  fd.append('user_id', params.user.email);
  fd.append('doc_type', docTypeMap[params.fileType]);
  fd.append('file', params.file);

  const res = await fetch('/api/upload', { method: 'POST', body: fd });
  return mustJson<{ ok: boolean; added_chunks: number; status_md: string }>(res);
}

export async function apiExport(params: {
  user: User;
  learningMode: LearningMode;
}) {
  const res = await fetch('/api/export', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      user_id: params.user.email,
      learning_mode: modeMap[params.learningMode],
    }),
  });
  return mustJson<{ markdown: string }>(res);
}

export async function apiSummary(params: {
  user: User;
  learningMode: LearningMode;
  language: Language;
}) {
  const res = await fetch('/api/summary', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      user_id: params.user.email,
      learning_mode: modeMap[params.learningMode],
      language_preference: langMap[params.language],
    }),
  });
  return mustJson<{ markdown: string }>(res);
}

// -----------------------------
// Feedback API (NEW)
// -----------------------------
export type FeedbackRating = 'helpful' | 'not_helpful';

export interface FeedbackParams {
  user: User;

  rating: FeedbackRating;

  // which assistant msg is being rated (optional but recommended)
  assistantMessageId?: string;

  // texts
  assistantText: string;
  userText?: string;

  // UI details
  tags?: string[]; // structured tags/chips
  comment?: string; // free-text

  // context
  refs?: string[];
  learningMode?: LearningMode;
  docType?: FileType | string;

  timestampMs?: number;
}

export async function apiFeedback(params: FeedbackParams) {
  const payload: Record<string, unknown> = {
    user_id: params.user.email,
    rating: params.rating,

    // Only include if present (avoid null noise)
    ...(params.assistantMessageId ? { assistant_message_id: params.assistantMessageId } : {}),

    assistant_text: params.assistantText,
    user_text: (params.userText ?? '').trim(),

    tags: params.tags ?? [],
    comment: (params.comment ?? '').trim(),
    refs: params.refs ?? [],

    learning_mode: params.learningMode ? modeMap[params.learningMode] : undefined,
    doc_type: resolveDocType(params.docType),

    timestamp_ms: params.timestampMs ?? Date.now(),
  };

  // Remove undefined keys (extra safety; FastAPI pydantic will ignore missing but this keeps payload clean)
  Object.keys(payload).forEach((k) => {
    if (payload[k] === undefined) delete payload[k];
  });

  const res = await fetch('/api/feedback', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(payload),
  });

  return mustJson<{ ok: boolean }>(res);
}

// Optional: export maps if other components need them
export const _maps = { modeMap, langMap, docTypeMap };