import { Platform } from "react-native";
import { loadToken, saveToken, clearToken } from "./storage";

/**
 * API base URL. On web the app is served from the same origin as the API, so we
 * use a relative path. On native (the Android APK) it must point at the public
 * HTTPS host, baked in at build time via EXPO_PUBLIC_API_URL.
 */
export const API_BASE =
  Platform.OS === "web"
    ? ""
    : (process.env.EXPO_PUBLIC_API_URL ?? "https://scan.beartariacampgrounds.com").replace(/\/+$/, "");

export interface ResourceCount {
  total: number;
  redeemed: number;
  remaining: number;
}

export interface TicketView {
  code: string;
  name: string;
  email: string;
  total: number;
  redeemed: number;
  remaining: number;
  ice: ResourceCount;
  extras: {
    carParking: boolean;
    rvParking: boolean;
    iceAccess: boolean;
    isDonor: boolean;
    freeUnder4: number;
  };
  ages: { bracket: string; count: number; free: boolean }[];
}

export class AuthError extends Error {}
export class ApiError extends Error {}

let cachedToken: string | null = null;

export async function getToken(): Promise<string | null> {
  if (cachedToken) return cachedToken;
  cachedToken = await loadToken();
  return cachedToken;
}

export async function login(pin: string): Promise<void> {
  const res = await fetch(`${API_BASE}/api/auth/login`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ pin }),
  });
  if (res.status === 401) throw new AuthError("Incorrect PIN");
  if (!res.ok) throw new ApiError(`Login failed (${res.status})`);
  const { token } = (await res.json()) as { token: string };
  cachedToken = token;
  await saveToken(token);
}

export async function logout(): Promise<void> {
  cachedToken = null;
  await clearToken();
}

async function authed<T>(path: string, init: RequestInit = {}): Promise<T> {
  const token = await getToken();
  if (!token) throw new AuthError("Not logged in");
  const res = await fetch(`${API_BASE}${path}`, {
    ...init,
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${token}`,
      ...(init.headers || {}),
    },
  });
  if (res.status === 401) {
    await logout();
    throw new AuthError("Session expired");
  }
  const text = await res.text();
  let body: any = undefined;
  if (text) {
    try {
      body = JSON.parse(text);
    } catch {
      body = text;
    }
  }
  if (!res.ok) {
    throw new ApiError(body?.error ?? body?.detail ?? `Request failed (${res.status})`);
  }
  return body as T;
}

export type LookupResult =
  | { ok: true; found: true; ticket: TicketView }
  | { ok: true; found: false }
  | { ok: false; reason: "db_error"; detail: string };

export function lookup(code: string): Promise<LookupResult> {
  return authed<LookupResult>("/api/lookup", {
    method: "POST",
    body: JSON.stringify({ code }),
  });
}

export type RedeemResult =
  | { ok: true; ticket: TicketView; checkedIn: number }
  | {
      ok: false;
      reason: "not_found" | "exhausted" | "insufficient" | "db_error";
      ticket?: TicketView;
      detail?: string;
    };

export type Resource = "tickets" | "ice";

export function redeem(code: string, count: number, resource: Resource = "tickets"): Promise<RedeemResult> {
  return authed<RedeemResult>("/api/redeem", {
    method: "POST",
    body: JSON.stringify({ code, count, resource }),
  });
}

export interface DonorLookup {
  found: boolean;
  email: string;
  name: string;
  online: number;
  offline: number;
  total: number;
  source: "master" | "transactions" | "none";
}

export type BanquetResult =
  | { ok: true; ticketName: string; donor: DonorLookup }
  | { ok: false; reason: "not_found" | "no_email" | "db_error" | "banquet_disabled"; detail?: string };

export function banquet(input: { code?: string; email?: string }): Promise<BanquetResult> {
  return authed<BanquetResult>("/api/banquet", {
    method: "POST",
    body: JSON.stringify(input),
  });
}

export function searchTickets(q: string): Promise<{ results: TicketView[] }> {
  return authed<{ results: TicketView[] }>(`/api/tickets?q=${encodeURIComponent(q)}`);
}

export interface AuditEntry {
  id: number;
  code: string;
  people: number;
  name: string;
  remainingAfter: number;
  at: string;
  action: "check-in" | "undo";
}

export function getAudit(opts: { code?: string; limit?: number } = {}): Promise<{
  enabled: boolean;
  entries: AuditEntry[];
}> {
  const params = new URLSearchParams();
  if (opts.code) params.set("code", opts.code);
  if (opts.limit) params.set("limit", String(opts.limit));
  const qs = params.toString();
  return authed<{ enabled: boolean; entries: AuditEntry[] }>(`/api/audit${qs ? `?${qs}` : ""}`);
}