import { notify } from "./notifications";

export interface Me {
  id: number;
  email: string;
  display_name: string | null;
  avatar_url: string | null;
  role: string;
  is_demo: boolean;
  can_read: boolean;
  can_write: boolean;
  pending_invites: number;
  preferences: Record<string, any>;
}

export interface DemoWhitelistEntry {
  id: number;
  email: string;
  note: string | null;
  added_by: string | null;
  created_at: string | null;
}

export interface Invite {
  id: number;
  email: string;
  status: "pending" | "approved" | "denied";
  note: string | null;
  requested_at: string | null;
  decided_at: string | null;
  decided_by: string | null;
}

export interface Tag {
  id: number;
  name: string;
  color: string | null;
  category: string;
  system: boolean;
  channel_count: number;
}

export interface Video {
  id: string;
  title: string | null;
  channel_id: string;
  channel_title: string | null;
  channel_thumbnail: string | null;
  channel_url: string;
  published_at: string | null;
  thumbnail_url: string | null;
  duration_seconds: number | null;
  view_count: number | null;
  is_short: boolean;
  live_status: string;
  status: string;
  position_seconds: number;
  saved: boolean; // is the video in the user's built-in Watch later playlist
  watch_url: string;
}

export interface VideoDetail {
  id: string;
  description: string | null;
  like_count: number | null;
  in_db: boolean;
  channel_id: string | null;
  channel_title: string | null;
  published_at: string | null;
  view_count: number | null;
  duration_seconds: number | null;
}

export interface FeedResponse {
  items: Video[];
  has_more: boolean;
  offset: number;
  limit: number;
}

export interface Playlist {
  id: number;
  name: string;
  kind: string; // "user" | "watch_later"
  source: string; // "local" | "youtube"
  yt_playlist_id: string | null;
  dirty: boolean; // linked local playlist has edits not yet pushed to YouTube
  item_count: number;
  total_duration_seconds: number;
  cover_thumbnail: string | null;
  has_video?: boolean; // only set when listed with ?contains=<video_id>
}

export interface PlaylistDetail {
  id: number;
  name: string;
  kind: string;
  source: string;
  yt_playlist_id: string | null;
  dirty: boolean;
  items: Video[];
}

export interface PushPlan {
  action: "create" | "update";
  to_insert: number;
  to_delete: number;
  to_reorder: number;
  yt_extra: number; // items on YouTube that the push would remove (divergence)
  units_estimate: number;
  remaining_today: number;
  affordable: boolean;
}

export interface PushResult {
  created: number;
  inserted: number;
  deleted: number;
  reordered: number;
  failures: string[];
  yt_playlist_id: string | null;
}

export interface FeedFilters {
  tags: number[];
  tagMode: "or" | "and";
  q: string;
  sort: string;
  // Re-roll token for the "shuffle" sort; bumped by the reshuffle button so the
  // feed re-queries with a fresh order. Ignored by every other sort.
  seed?: number;
  // "my" = only your subscriptions (default); "all" = the whole shared catalog.
  scope: "my" | "all";
  includeNormal: boolean;
  includeShorts: boolean;
  includeLive: boolean;
  show: string;
  channelId?: string;
  channelName?: string;
  maxAgeDays?: number;
  minDuration?: number;
  maxDuration?: number;
  dateFrom?: string;
  dateTo?: string;
}

export interface VersionInfo {
  app_version: string;
  git_sha: string;
  build_date: string | null;
  db_revision: string | null;
}

class HttpError extends Error {
  status: number;
  detail?: string; // server-provided reason (FastAPI's `detail`), when present
  constructor(status: number, detail?: string) {
    super(detail || `HTTP ${status}`);
    this.status = status;
    this.detail = detail;
  }
}

// Collapse bursts of connection failures (e.g. while the server restarts) into a
// single notification rather than one per failed request.
let lastErrorNotifiedAt = 0;
function notifyErrorThrottled(title: string, message: string): void {
  const now = Date.now();
  if (now - lastErrorNotifiedAt < 30_000) return;
  lastErrorNotifiedAt = now;
  notify({ level: "error", title, message });
}

async function req(url: string, opts: RequestInit = {}): Promise<any> {
  const method = opts.method ?? "GET";
  let r: Response;
  try {
    r = await fetch(url, {
      credentials: "include",
      headers: { "Content-Type": "application/json" },
      ...opts,
    });
  } catch (e) {
    notifyErrorThrottled(
      "Connection lost",
      "Couldn't reach the server — it may be restarting. This will clear once it's back."
    );
    throw e;
  }
  if (!r.ok) {
    // Capture the server's reason (FastAPI returns `{ detail }`) so callers can react.
    let detail: string | undefined;
    try {
      const body = await r.json();
      if (body && typeof body.detail === "string") detail = body.detail;
    } catch {
      /* no JSON body */
    }
    // Server faults are worth surfacing; 401/403/404 etc. are handled by callers.
    if (r.status >= 500) {
      notifyErrorThrottled(`Server error ${r.status}`, `${method} ${url}`);
    }
    throw new HttpError(r.status, detail);
  }
  return r.status === 204 ? null : r.json();
}

// The filter half of the query (everything except paging/sort), shared by the feed and
// the facet-count endpoint so both see exactly the same filter context.
function filterParams(f: FeedFilters): URLSearchParams {
  const p = new URLSearchParams();
  f.tags.forEach((t) => p.append("tags", String(t)));
  p.set("tag_mode", f.tagMode);
  if (f.q) p.set("q", f.q);
  p.set("scope", f.scope);
  p.set("show_normal", String(f.includeNormal));
  p.set("include_shorts", String(f.includeShorts));
  p.set("include_live", String(f.includeLive));
  p.set("show", f.show);
  if (f.channelId) p.set("channel_id", f.channelId);
  if (f.maxAgeDays) p.set("max_age_days", String(f.maxAgeDays));
  if (f.dateFrom) p.set("published_after", f.dateFrom);
  if (f.dateTo) p.set("published_before", f.dateTo);
  if (f.minDuration != null) p.set("min_duration", String(f.minDuration));
  if (f.maxDuration != null) p.set("max_duration", String(f.maxDuration));
  return p;
}

function feedQuery(f: FeedFilters, offset: number, limit: number): string {
  const p = filterParams(f);
  p.set("sort", f.sort);
  if (f.sort === "shuffle" && f.seed) p.set("seed", String(f.seed));
  p.set("offset", String(offset));
  p.set("limit", String(limit));
  return p.toString();
}

export interface SyncStatus {
  subscriptions: number;
  channels_total: number;
  channels_backfilling: number;
  videos_total: number;
  pending_enrich: number;
  quota_used_today: number;
  quota_remaining_today: number;
  paused: boolean;
  is_admin: boolean;
}

export interface MyStatus {
  channels_total: number;
  channels_details_synced: number;
  channels_recent_synced: number;
  channels_deep_done: number;
  channels_recent_pending: number;
  channels_deep_pending: number;
  channels_deep_requested: number;
  deep_pending_count: number;
  deep_eta_seconds: number;
  my_videos: number;
  total_videos: number;
  quota_used_today: number;
  quota_remaining_today: number;
  paused: boolean;
}

export interface MyUsage {
  today: number;
  last_7d: number;
  last_30d: number;
  all_time: number;
  by_action: Record<string, number>;
}

export interface AdminQuotaRow {
  user_id: number | null;
  email: string;
  total: number;
  by_action: Record<string, number>;
}

export interface AdminQuota {
  range_days: number;
  rows: AdminQuotaRow[];
  daily: { day: string; total: number }[];
}

export interface ManagedChannel {
  id: string;
  title: string | null;
  handle: string | null;
  thumbnail_url: string | null;
  subscriber_count: number | null;
  video_count: number | null;
  stored_videos: number;
  priority: number;
  hidden: boolean;
  deep_requested: boolean;
  deep_in_queue: boolean;
  tag_ids: number[];
  details_synced: boolean;
  recent_synced: boolean;
  backfill_done: boolean;
}

export interface Account {
  id: number;
  email: string;
  display_name: string | null;
  avatar_url: string | null;
  active: boolean;
}

export const api = {
  me: (): Promise<Me> => req("/api/me"),
  accounts: (): Promise<Account[]> => req("/api/me/accounts"),
  switchAccount: (userId: number): Promise<{ ok: boolean; user_id: number }> =>
    req("/api/me/switch", { method: "POST", body: JSON.stringify({ user_id: userId }) }),
  version: (): Promise<VersionInfo> => req("/api/version"),
  tags: (): Promise<Tag[]> => req("/api/tags"),
  status: (): Promise<SyncStatus> => req("/api/sync/status"),
  feed: (f: FeedFilters, offset: number, limit: number): Promise<FeedResponse> =>
    req(`/api/feed?${feedQuery(f, offset, limit)}`),
  feedCount: (f: FeedFilters): Promise<{ count: number }> =>
    req(`/api/feed/count?${feedQuery(f, 0, 0)}`),
  facets: (f: FeedFilters): Promise<{ counts: Record<string, number> }> =>
    req(`/api/facets?${filterParams(f).toString()}`),
  setState: (id: string, status: string) =>
    req(`/api/videos/${id}/state`, { method: "POST", body: JSON.stringify({ status }) }),
  saveProgress: (id: string, positionSeconds: number, durationSeconds: number) =>
    req(`/api/videos/${id}/progress`, {
      method: "POST",
      body: JSON.stringify({
        position_seconds: Math.floor(positionSeconds),
        duration_seconds: Math.floor(durationSeconds),
      }),
    }),
  videoDetail: (id: string): Promise<VideoDetail> => req(`/api/videos/${id}`),
  pauseSync: () => req("/api/sync/pause", { method: "POST" }),
  resumeSync: () => req("/api/sync/resume", { method: "POST" }),
  savePrefs: (p: Record<string, any>) =>
    req("/api/me/preferences", { method: "PUT", body: JSON.stringify(p) }),

  // --- channel manager ---
  myStatus: (): Promise<MyStatus> => req("/api/sync/my-status"),
  channels: (): Promise<ManagedChannel[]> => req("/api/channels"),
  updateChannel: (
    id: string,
    patch: { priority?: number; hidden?: boolean; deep_requested?: boolean }
  ) => req(`/api/channels/${id}`, { method: "PATCH", body: JSON.stringify(patch) }),
  deepAll: (on = true) =>
    req(`/api/sync/deep-all?on=${on}`, { method: "POST" }),
  attachChannelTag: (id: string, tagId: number) =>
    req(`/api/channels/${id}/tags`, { method: "POST", body: JSON.stringify({ tag_id: tagId }) }),
  detachChannelTag: (id: string, tagId: number) =>
    req(`/api/channels/${id}/tags/${tagId}`, { method: "DELETE" }),
  unsubscribeChannel: (id: string) =>
    req(`/api/channels/${id}/subscription`, { method: "DELETE" }),
  syncSubscriptions: () => req("/api/sync/subscriptions", { method: "POST" }),

  // --- playlists ---
  playlists: (containsVideoId?: string): Promise<Playlist[]> =>
    req(`/api/playlists${containsVideoId ? `?contains=${containsVideoId}` : ""}`),
  playlist: (id: number): Promise<PlaylistDetail> => req(`/api/playlists/${id}`),
  createPlaylist: (name: string): Promise<Playlist> =>
    req("/api/playlists", { method: "POST", body: JSON.stringify({ name }) }),
  renamePlaylist: (id: number, name: string): Promise<Playlist> =>
    req(`/api/playlists/${id}`, { method: "PATCH", body: JSON.stringify({ name }) }),
  deletePlaylist: (id: number, onYoutube = false) =>
    req(`/api/playlists/${id}${onYoutube ? "?on_youtube=true" : ""}`, { method: "DELETE" }),
  addToPlaylist: (id: number, videoId: string) =>
    req(`/api/playlists/${id}/items`, {
      method: "POST",
      body: JSON.stringify({ video_id: videoId }),
    }),
  removeFromPlaylist: (id: number, videoId: string) =>
    req(`/api/playlists/${id}/items/${videoId}`, { method: "DELETE" }),
  reorderPlaylist: (id: number, videoIds: string[]) =>
    req(`/api/playlists/${id}/order`, {
      method: "PUT",
      body: JSON.stringify({ video_ids: videoIds }),
    }),
  // Bookmark shortcut for the built-in Watch later playlist.
  watchLaterAdd: (videoId: string) =>
    req("/api/playlists/watch-later", {
      method: "POST",
      body: JSON.stringify({ video_id: videoId }),
    }),
  watchLaterRemove: (videoId: string) =>
    req(`/api/playlists/watch-later/${videoId}`, { method: "DELETE" }),
  syncYoutubePlaylists: (): Promise<{ synced: number; reason?: string }> =>
    req("/api/playlists/sync-youtube", { method: "POST" }),
  revertPlaylist: (id: number): Promise<{ items: number }> =>
    req(`/api/playlists/${id}/revert-youtube`, { method: "POST" }),
  playlistPushPlan: (id: number): Promise<PushPlan> =>
    req(`/api/playlists/${id}/push-plan`),
  pushPlaylist: (id: number): Promise<PushResult> =>
    req(`/api/playlists/${id}/push`, { method: "POST" }),

  // --- quota usage ---
  myUsage: (): Promise<MyUsage> => req("/api/quota/my-usage"),
  adminQuota: (days = 30): Promise<AdminQuota> => req(`/api/quota/admin?days=${days}`),

  // --- onboarding / admin ---
  requestAccess: (email: string): Promise<{ status: string }> =>
    req("/auth/request-access", { method: "POST", body: JSON.stringify({ email }) }),
  // Hidden demo entry: a whitelisted email logs into the shared demo account, no Google
  // sign-in. Returns whether a session was established.
  demoLogin: (email: string): Promise<{ authenticated: boolean }> =>
    req("/auth/demo", { method: "POST", body: JSON.stringify({ email }) }),
  adminDemoWhitelist: (): Promise<DemoWhitelistEntry[]> =>
    req("/api/admin/demo/whitelist"),
  addDemoWhitelist: (email: string): Promise<DemoWhitelistEntry> =>
    req("/api/admin/demo/whitelist", { method: "POST", body: JSON.stringify({ email }) }),
  removeDemoWhitelist: (id: number) =>
    req(`/api/admin/demo/whitelist/${id}`, { method: "DELETE" }),
  resetDemo: (): Promise<{ reset: boolean; playlists_seeded: number }> =>
    req("/api/admin/demo/reset", { method: "POST" }),
  adminInvites: (status?: string): Promise<Invite[]> =>
    req(`/api/admin/invites${status ? `?status=${status}` : ""}`),
  approveInvite: (id: number) =>
    req(`/api/admin/invites/${id}/approve`, { method: "POST" }),
  denyInvite: (id: number) => req(`/api/admin/invites/${id}/deny`, { method: "POST" }),
  addInvite: (email: string) =>
    req("/api/admin/invites", { method: "POST", body: JSON.stringify({ email }) }),

  // --- user tags ---
  createTag: (t: { name: string; color?: string; category?: string }) =>
    req("/api/tags", { method: "POST", body: JSON.stringify(t) }),
  updateTag: (id: number, patch: { name?: string; color?: string }) =>
    req(`/api/tags/${id}`, { method: "PATCH", body: JSON.stringify(patch) }),
  deleteTag: (id: number) => req(`/api/tags/${id}`, { method: "DELETE" }),
};

export { HttpError };