const API_BASE_URL = import.meta.env.VITE_API_BASE_URL || "http://localhost:8000/api";
const UPLOAD_TIMEOUT = parseInt(import.meta.env.VITE_UPLOAD_TIMEOUT || "600000", 10);

let authToken = null;
let tokenRefreshTimer = null;

export function setToken(token) {
  authToken = token;
  localStorage.setItem("authToken", token);
  scheduleTokenRefresh();
}

export function getToken() {
  if (!authToken) {
    authToken = localStorage.getItem("authToken");
  }
  return authToken;
}

export function clearToken() {
  authToken = null;
  localStorage.removeItem("authToken");
  if (tokenRefreshTimer) {
    clearTimeout(tokenRefreshTimer);
  }
}

function scheduleTokenRefresh() {
  // Refresh token 5 minutes before expiry (assuming 24h token)
  const refreshIn = 23 * 60 * 60 * 1000; // 23 hours
  if (tokenRefreshTimer) {
    clearTimeout(tokenRefreshTimer);
  }
  tokenRefreshTimer = setTimeout(async () => {
    try {
      // Re-login would require stored credentials
      // For now, just notify user to re-login
      console.warn("Token expiring soon, please re-login");
    } catch (error) {
      console.error("Token refresh failed:", error);
    }
  }, refreshIn);
}

async function request(endpoint, options = {}) {
  const url = `${API_BASE_URL}${endpoint}`;
  const headers = {
    "Content-Type": "application/json",
    ...options.headers,
  };

  const token = getToken();
  if (token) {
    headers["Authorization"] = `Bearer ${token}`;
  }

  const response = await fetch(url, {
    ...options,
    headers,
  });

  if (response.status === 401) {
    const error = await response.json();
    if (error.detail?.error === "token_expired") {
      clearToken();
      window.electronAPI.navigate("login");
      throw new Error("Session expired, please login again");
    }
    throw new Error(error.detail || "Unauthorized");
  }

  if (!response.ok) {
    const error = await response.json().catch(() => ({}));
    throw new Error(error.detail || `HTTP error ${response.status}`);
  }

  // Handle blob responses for export
  if (options.responseType === "blob") {
    return response.blob();
  }

  return response.json();
}

// Auth API
export async function login(email, password) {
  const data = await request("/login", {
    method: "POST",
    body: JSON.stringify({ email, password }),
  });
  setToken(data.token);
  localStorage.setItem("userEmail", data.email);
  localStorage.setItem("userRole", data.role);
  return data;
}

export async function getMe() {
  return request("/me");
}

// Meetings API
export async function getMeetings() {
  return request("/meetings");
}

export async function getMeeting(id) {
  return request(`/meetings/${id}`);
}

export async function createMeeting(meeting) {
  return request("/meetings", {
    method: "POST",
    body: JSON.stringify(meeting),
  });
}

export async function updateMeeting(id, meeting) {
  return request(`/meetings/${id}`, {
    method: "PUT",
    body: JSON.stringify(meeting),
  });
}

export async function deleteMeeting(id) {
  return request(`/meetings/${id}`, {
    method: "DELETE",
  });
}

export async function updateActionItem(meetingId, actionId, data) {
  return request(`/meetings/${meetingId}/actions/${actionId}`, {
    method: "PUT",
    body: JSON.stringify(data),
  });
}

// AI API
export async function summarizeTranscript(transcript) {
  return request("/ai/summarize", {
    method: "POST",
    body: JSON.stringify({ transcript }),
  });
}

export async function transcribeAudio(file, onProgress = null) {
  const url = `${API_BASE_URL}/ai/transcribe-audio-stream`;
  const formData = new FormData();
  formData.append("file", file);

  const token = getToken();

  return new Promise((resolve, reject) => {
    // Use fetch for SSE support
    fetch(url, {
      method: "POST",
      headers: {
        Authorization: token ? `Bearer ${token}` : undefined,
      },
      body: formData,
    })
      .then((response) => {
        if (response.status === 401) {
          clearToken();
          window.electronAPI?.navigate("login");
          throw new Error("Session expired, please login again");
        }

        if (!response.ok) {
          return response.json().then((error) => {
            throw new Error(error.detail || `HTTP error ${response.status}`);
          });
        }

        if (onProgress) {
          onProgress({ phase: "processing", progress: 0, message: "處理中..." });
        }

        // Read SSE stream
        const reader = response.body.getReader();
        const decoder = new TextDecoder();
        let buffer = "";
        let result = null;
        let totalChunks = 0;
        let processedChunks = 0;

        function processLine(line) {
          if (line.startsWith("data: ")) {
            try {
              const data = JSON.parse(line.slice(6));

              switch (data.event) {
                case "start":
                case "segmenting":
                  if (onProgress) {
                    onProgress({
                      phase: "processing",
                      progress: 5,
                      message: data.message,
                    });
                  }
                  break;

                case "segments_ready":
                  totalChunks = data.total;
                  if (onProgress) {
                    onProgress({
                      phase: "transcribing",
                      progress: 10,
                      total: totalChunks,
                      current: 0,
                      message: data.message,
                    });
                  }
                  break;

                case "chunk_start":
                  if (onProgress) {
                    const progress = 10 + ((data.chunk - 1) / totalChunks) * 85;
                    onProgress({
                      phase: "transcribing",
                      progress: Math.round(progress),
                      total: totalChunks,
                      current: data.chunk,
                      message: data.message,
                    });
                  }
                  break;

                case "chunk_done":
                  processedChunks++;
                  if (onProgress) {
                    const progress = 10 + (data.chunk / totalChunks) * 85;
                    onProgress({
                      phase: "transcribing",
                      progress: Math.round(progress),
                      total: totalChunks,
                      current: data.chunk,
                      message: data.message,
                    });
                  }
                  break;

                case "chunk_error":
                  console.warn(`Chunk ${data.chunk} error: ${data.message}`);
                  break;

                case "error":
                  throw new Error(data.message);

                case "complete":
                  result = {
                    transcript: data.transcript,
                    chunks_processed: data.chunks_processed,
                    chunks_total: data.chunks_total,
                    total_duration_seconds: data.duration,
                    language: "zh",
                  };
                  if (onProgress) {
                    onProgress({
                      phase: "complete",
                      progress: 100,
                      message: "轉錄完成",
                    });
                  }
                  break;
              }
            } catch (e) {
              console.warn("SSE parse error:", e, line);
            }
          }
        }

        function read() {
          reader
            .read()
            .then(({ done, value }) => {
              if (done) {
                // Process any remaining buffer
                if (buffer.trim()) {
                  buffer.split("\n").forEach(processLine);
                }
                if (result) {
                  resolve(result);
                } else {
                  reject(new Error("Transcription failed - no result received"));
                }
                return;
              }

              buffer += decoder.decode(value, { stream: true });
              const lines = buffer.split("\n");
              buffer = lines.pop() || ""; // Keep incomplete line in buffer

              lines.forEach(processLine);
              read();
            })
            .catch(reject);
        }

        read();
      })
      .catch(reject);
  });
}

// Legacy non-streaming version (fallback)
export async function transcribeAudioLegacy(file, onProgress = null) {
  const url = `${API_BASE_URL}/ai/transcribe-audio`;
  const formData = new FormData();
  formData.append("file", file);

  const token = getToken();

  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();

    xhr.upload.addEventListener("progress", (event) => {
      if (event.lengthComputable && onProgress) {
        const percentComplete = Math.round((event.loaded / event.total) * 100);
        onProgress({ phase: "uploading", progress: percentComplete });
      }
    });

    xhr.addEventListener("load", () => {
      if (xhr.status >= 200 && xhr.status < 300) {
        try {
          const response = JSON.parse(xhr.responseText);
          resolve(response);
        } catch (e) {
          reject(new Error("Invalid response format"));
        }
      } else if (xhr.status === 401) {
        clearToken();
        window.electronAPI?.navigate("login");
        reject(new Error("Session expired, please login again"));
      } else {
        try {
          const error = JSON.parse(xhr.responseText);
          reject(new Error(error.detail || `HTTP error ${xhr.status}`));
        } catch (e) {
          reject(new Error(`HTTP error ${xhr.status}`));
        }
      }
    });

    xhr.addEventListener("error", () => {
      reject(new Error("Network error"));
    });

    xhr.addEventListener("timeout", () => {
      reject(new Error("Request timeout"));
    });

    xhr.open("POST", url, true);
    xhr.timeout = UPLOAD_TIMEOUT;
    if (token) {
      xhr.setRequestHeader("Authorization", `Bearer ${token}`);
    }
    xhr.send(formData);

    // Notify processing phase after upload completes
    if (onProgress) {
      xhr.upload.addEventListener("loadend", () => {
        onProgress({ phase: "processing", progress: 0 });
      });
    }
  });
}

// Export API
export async function exportMeeting(id) {
  return request(`/meetings/${id}/export`, {
    responseType: "blob",
  });
}