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

export interface InterviewFramework {
  id: string;
  name: string;
}

export interface CreateSessionResponse {
  session_id: string;
  framework_id: string;
  room_id: string;
  status: string;
  opening_message: string;
  first_question: string;
}

export interface MessageResponse {
  reply: string;
  stage: "in_progress" | "next_question" | "follow_up" | "closing";
  finished: boolean;
}

export interface QAPair {
  question_text: string;
  answer_cleaned: string;
  follow_ups?: QAPair[];
}

export interface SectionResult {
  section_title: string;
  objective: string[];
  qa_pairs: QAPair[];
  section_summary: string;
}

export interface InterviewResult {
  framework_name: string;
  mode: string;
  language: string;
  started_at: string;
  ended_at: string;
  summary: string;
  goals: string[];
  section_results: SectionResult[];
  key_insights: string[];
  unresolved_items: string[];
}

export interface FinishSessionResponse {
  session_id: string;
  room_id: string;
  status: string;
  result: InterviewResult;
}

export interface StreamMetadata {
  finished: boolean;
  stage: "next_question" | "follow_up" | "closing";
}

export type AudioServerEvent =
  | { type: "token_chunk"; payload: string }
  | { type: "assistant_reply"; payload: string }
  | { type: "session_done" }
  | { type: "error"; payload: string };

// ─── Base Client ──────────────────────────────────────────────────────────────

const INTERVIEW_BASE_URL =
  ((import.meta as unknown as { env: Record<string, string> }).env
    .VITE_ORCHESTRATION_API_BASE_URL) ?? "http://localhost:8080";

async function request<T>(path: string, options?: RequestInit): Promise<T> {
  const res = await fetch(`${INTERVIEW_BASE_URL}${path}`, {
    headers: { "Content-Type": "application/json", ...options?.headers },
    ...options,
  });
  if (!res.ok) {
    const err = await res.json().catch(() => ({ error: `HTTP ${res.status}` }));
    throw new Error(err.error ?? `HTTP ${res.status}`);
  }
  return res.json() as Promise<T>;
}

// ─── Endpoints ────────────────────────────────────────────────────────────────

export const getFrameworks = (): Promise<InterviewFramework[]> =>
  request<InterviewFramework[]>("/frameworks");

export const createSession = (
  frameworkId: string,
  userId: string,
  roomId: string,
  mode: "text" | "audio" = "text",
  language = "id-ID"
): Promise<CreateSessionResponse> =>
  request<CreateSessionResponse>("/sessions", {
    method: "POST",
    body: JSON.stringify({ framework_id: frameworkId, user_id: userId, room_id: roomId, mode, language }),
  });

export const sendMessage = (
  sessionId: string,
  message: string
): Promise<MessageResponse> =>
  request<MessageResponse>(`/sessions/${sessionId}/message`, {
    method: "POST",
    body: JSON.stringify({ message }),
  });

export const finishSession = (
  sessionId: string
): Promise<FinishSessionResponse> =>
  request<FinishSessionResponse>(`/sessions/${sessionId}/finish`, {
    method: "POST",
  });

export const getInterviewResult = (roomId: string): Promise<InterviewResult> =>
  request<InterviewResult>(`/rooms/${roomId}/result`);

// SSE streaming — returns raw Response so caller can read the stream
export const streamMessage = (
  sessionId: string,
  message: string
): Promise<Response> =>
  fetch(`${INTERVIEW_BASE_URL}/sessions/${sessionId}/stream-message`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ message }),
  });

// ─── Audio WebSocket ──────────────────────────────────────────────────────────

export interface AudioSessionHandle {
  sendAudioChunk: (chunk: ArrayBuffer) => void;
  sendEndUtterance: () => void;
  close: () => void;
}

export function openAudioSession(
  sessionId: string,
  onEvent: (event: AudioServerEvent) => void,
  onAudio: (audioBuffer: ArrayBuffer) => void,
  onClose: () => void
): AudioSessionHandle {
  const wsBase = INTERVIEW_BASE_URL.replace(/^http/, "ws");
  const ws = new WebSocket(`${wsBase}/ws/audio?session_id=${sessionId}`);
  ws.binaryType = "arraybuffer";

  ws.onmessage = (e) => {
    if (e.data instanceof ArrayBuffer) {
      onAudio(e.data);
    } else {
      try {
        const parsed = JSON.parse(e.data) as AudioServerEvent;
        onEvent(parsed);
      } catch {
        // ignore malformed messages
      }
    }
  };

  ws.onclose = onClose;

  return {
    sendAudioChunk: (chunk) => {
      if (ws.readyState === WebSocket.OPEN) ws.send(chunk);
    },
    sendEndUtterance: () => {
      if (ws.readyState === WebSocket.OPEN)
        ws.send(JSON.stringify({ type: "end_utterance" }));
    },
    close: () => ws.close(),
  };
}