import { call, os } from "@orpc/server";
import { z } from "zod";
import { randomUUID } from "crypto";
import { createKV } from "../lib/create-kv.js";

const AvailabilitySchema = z.object({
  id: z.string(),
  date: z.string(), // YYYY-MM-DD
  time: z.string(), // HH:MM
  durationMinutes: z.number().int().positive(),
  status: z.enum(["free", "reserved"]),
  reservedByBookingId: z.string().optional(),
  createdAt: z.string(),
});

export type Availability = z.output<typeof AvailabilitySchema>;

const kv = createKV<Availability>("availability");

// Minimal Owner-Prüfung über Sessions/Users KV
type Session = { id: string; userId: string; expiresAt: string; createdAt: string };
type User = { id: string; username: string; email: string; passwordHash: string; role: "customer" | "owner"; createdAt: string };
const sessionsKV = createKV<Session>("sessions");
const usersKV = createKV<User>("users");

async function assertOwner(sessionId: string): Promise<void> {
  const session = await sessionsKV.getItem(sessionId);
  if (!session) throw new Error("Invalid session");
  if (new Date(session.expiresAt) < new Date()) throw new Error("Session expired");
  const user = await usersKV.getItem(session.userId);
  if (!user || user.role !== "owner") throw new Error("Forbidden");
}

const create = os
  .input(
    z.object({
      sessionId: z.string(),
      date: z.string().regex(/^\d{4}-\d{2}-\d{2}$/),
      time: z.string().regex(/^\d{2}:\d{2}$/),
      durationMinutes: z.number().int().positive(),
    })
  )
  .handler(async ({ input }) => {
    try {
      await assertOwner(input.sessionId);
      // Prevent duplicate slot on same date+time
      const existing = await kv.getAllItems();
      const conflict = existing.some((s) => s.date === input.date && s.time === input.time);
      if (conflict) {
        throw new Error("Es existiert bereits ein Slot zu diesem Datum und dieser Uhrzeit.");
      }
      const id = randomUUID();
      const slot: Availability = {
        id,
        date: input.date,
        time: input.time,
        durationMinutes: input.durationMinutes,
        status: "free",
        createdAt: new Date().toISOString(),
      };
      await kv.setItem(id, slot);
      return slot;
    } catch (err) {
      console.error("availability.create error", err);
      throw err;
    }
  });

const update = os
  .input(AvailabilitySchema.extend({ sessionId: z.string() }))
  .handler(async ({ input }) => {
    await assertOwner(input.sessionId);
    const { sessionId, ...rest } = input as any;
    await kv.setItem(rest.id, rest as Availability);
    return rest as Availability;
  });

const remove = os
  .input(z.object({ sessionId: z.string(), id: z.string() }))
  .handler(async ({ input }) => {
    await assertOwner(input.sessionId);
    const slot = await kv.getItem(input.id);
    if (slot && slot.status === "reserved") throw new Error("Cannot delete reserved slot");
    await kv.removeItem(input.id);
  });

const list = os.handler(async () => {
  const allSlots = await kv.getAllItems();
  
  // Auto-delete past slots
  const today = new Date().toISOString().split("T")[0]; // YYYY-MM-DD
  const now = new Date();
  const currentTime = `${String(now.getHours()).padStart(2, "0")}:${String(now.getMinutes()).padStart(2, "0")}`;
  
  let deletedCount = 0;
  const slotsToDelete: string[] = [];
  
  // Identify past slots for deletion
  allSlots.forEach(slot => {
    const isPastDate = slot.date < today;
    const isPastTime = slot.date === today && slot.time <= currentTime;
    
    if (isPastDate || isPastTime) {
      slotsToDelete.push(slot.id);
    }
  });
  
  // Delete past slots (only if not reserved)
  for (const slotId of slotsToDelete) {
    const slot = await kv.getItem(slotId);
    if (slot && slot.status !== "reserved") {
      await kv.removeItem(slotId);
      deletedCount++;
    }
  }
  
  if (deletedCount > 0) {
    console.log(`Auto-deleted ${deletedCount} past availability slots`);
  }
  
  // Return remaining slots (all are now current/future)
  const remainingSlots = allSlots.filter(slot => !slotsToDelete.includes(slot.id));
  
  return remainingSlots;
});

const get = os.input(z.string()).handler(async ({ input }) => {
  return kv.getItem(input);
});

const getByDate = os
  .input(z.string()) // YYYY-MM-DD
  .handler(async ({ input }) => {
    const all = await kv.getAllItems();
    return all.filter((s) => s.date === input);
  });

// Cleanup function to manually delete past slots
const cleanupPastSlots = os
  .input(z.object({ sessionId: z.string() }))
  .handler(async ({ input }) => {
    await assertOwner(input.sessionId);
    
    const allSlots = await kv.getAllItems();
    const today = new Date().toISOString().split("T")[0];
    const now = new Date();
    const currentTime = `${String(now.getHours()).padStart(2, "0")}:${String(now.getMinutes()).padStart(2, "0")}`;
    
    let deletedCount = 0;
    
    for (const slot of allSlots) {
      const isPastDate = slot.date < today;
      const isPastTime = slot.date === today && slot.time <= currentTime;
      
      if ((isPastDate || isPastTime) && slot.status !== "reserved") {
        await kv.removeItem(slot.id);
        deletedCount++;
      }
    }
    
    console.log(`Manual cleanup: deleted ${deletedCount} past availability slots`);
    return { deletedCount, message: `${deletedCount} vergangene Slots wurden gelöscht.` };
  });

const live = {
  list: os.handler(async function* ({ signal }) {
    yield call(list, {}, { signal });
    for await (const _ of kv.subscribe()) {
      yield call(list, {}, { signal });
    }
  }),
  byDate: os
    .input(z.string())
    .handler(async function* ({ input, signal }) {
      yield call(getByDate, input, { signal });
      for await (const _ of kv.subscribe()) {
        yield call(getByDate, input, { signal });
      }
    }),
};

export const router = {
  create,
  update,
  remove,
  list,
  get,
  getByDate,
  cleanupPastSlots,
  live,
};