import { afterAll, beforeAll, beforeEach, describe, expect, test } from "vitest";
import { PrismaPg } from "@prisma/adapter-pg";
import { PrismaClient } from "@/generated/prisma/client";
import {
  BookingConflictError,
  cancelBooking,
  confirmHold,
  createHold,
  expireStaleHolds,
  markComplete,
  markNoShow,
  rescheduleBooking,
} from "@/lib/booking";
import { seed, type SeedResult } from "@/lib/seed";

const adapter = new PrismaPg({ connectionString: process.env.DATABASE_URL });
const db = new PrismaClient({ adapter });

let fx: SeedResult;
let serviceId: string;
let therapistA: string;
let therapistB: string;
let roomA: string;
let roomB: string;
let customerId: string;

beforeAll(async () => {
  fx = await seed(db);
  serviceId = fx.services.find((s) => s.name === "60-minute Swedish")!.id;
  therapistA = fx.therapists[0].id;
  therapistB = fx.therapists[1].id;
  roomA = fx.rooms[0].id;
  roomB = fx.rooms[1].id;
  customerId = fx.customers[0].id;
});

afterAll(async () => {
  await db.$disconnect();
});

beforeEach(async () => {
  await db.booking.deleteMany();
});

const D = (iso: string) => new Date(iso);

describe("createHold", () => {
  test("inserts a HOLD with computed endsAt and roomReleasedAt", async () => {
    const startsAt = D("2026-05-05T14:00:00Z");
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt,
    });
    // 60-min Swedish, 15-min buffer
    expect(hold.endsAt).toEqual(D("2026-05-05T15:00:00Z"));
    expect(hold.roomReleasedAt).toEqual(D("2026-05-05T15:15:00Z"));
    expect(hold.priceCents).toBe(9000);
    expect(hold.depositCents).toBe(2000);

    const row = await db.booking.findUnique({ where: { id: hold.id } });
    expect(row?.status).toBe("HOLD");
    expect(row?.holdExpiresAt).toBeTruthy();
  });

  test("conflicting createHold (same therapist, overlapping) throws BookingConflictError", async () => {
    await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await expect(
      createHold(db, {
        customerId,
        serviceId,
        therapistId: therapistA,        // same therapist
        roomId: roomB,                   // different room
        startsAt: D("2026-05-05T14:30:00Z"),
      }),
    ).rejects.toBeInstanceOf(BookingConflictError);
  });

  test("conflicting createHold (same room within buffer) throws BookingConflictError", async () => {
    await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    // Next slot after 11:00 is 11:15 because of the buffer.
    await expect(
      createHold(db, {
        customerId,
        serviceId,
        therapistId: therapistB,
        roomId: roomA,                   // same room
        startsAt: D("2026-05-05T15:00:00Z"), // exactly at end — within buffer
      }),
    ).rejects.toBeInstanceOf(BookingConflictError);
  });

  test("non-overlapping createHold succeeds after the room buffer", async () => {
    await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    const hold2 = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistB,
      roomId: roomA,
      startsAt: D("2026-05-05T15:15:00Z"), // exactly when buffer ends
    });
    expect(hold2.id).toBeTruthy();
  });

  test("inactive service is rejected", async () => {
    await db.service.update({
      where: { id: serviceId },
      data: { active: false },
    });
    try {
      await expect(
        createHold(db, {
          customerId,
          serviceId,
          therapistId: therapistA,
          roomId: roomA,
          startsAt: D("2026-05-05T14:00:00Z"),
        }),
      ).rejects.toThrow(/inactive/);
    } finally {
      await db.service.update({
        where: { id: serviceId },
        data: { active: true },
      });
    }
  });

  test("custom holdMinutes is honored", async () => {
    const before = Date.now();
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
      holdMinutes: 30,
    });
    const expected = before + 30 * 60_000;
    // Allow 5 seconds of drift for the test execution time.
    expect(hold.holdExpiresAt.getTime()).toBeGreaterThanOrEqual(expected - 5000);
    expect(hold.holdExpiresAt.getTime()).toBeLessThanOrEqual(expected + 5000);
  });
});

describe("confirmHold", () => {
  test("flips a HOLD to CONFIRMED and clears holdExpiresAt", async () => {
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await confirmHold(db, hold.id);
    const row = await db.booking.findUnique({ where: { id: hold.id } });
    expect(row?.status).toBe("CONFIRMED");
    expect(row?.holdExpiresAt).toBeNull();
  });
});

describe("cancelBooking", () => {
  async function makeBooking(status: "HOLD" | "CONFIRMED" | "CANCELLED" | "COMPLETED" | "NO_SHOW" = "CONFIRMED") {
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    if (status !== "HOLD") {
      await db.booking.update({
        where: { id: hold.id },
        data: { status, holdExpiresAt: null },
      });
    }
    return hold;
  }

  test("cancels a CONFIRMED booking and records audit fields", async () => {
    const hold = await makeBooking("CONFIRMED");
    const result = await cancelBooking(db, {
      bookingId: hold.id,
      cancelledByUserId: customerId,
      reason: "test cancel",
    });
    expect(result).toEqual({ kind: "cancelled", alreadyCancelled: false });

    const row = await db.booking.findUnique({ where: { id: hold.id } });
    expect(row?.status).toBe("CANCELLED");
    expect(row?.cancelledBy).toBe(customerId);
    expect(row?.cancelReason).toBe("test cancel");
    expect(row?.cancelledAt).toBeTruthy();
  });

  test("cancels a HOLD booking", async () => {
    const hold = await makeBooking("HOLD");
    const result = await cancelBooking(db, {
      bookingId: hold.id,
      cancelledByUserId: customerId,
    });
    expect(result.kind).toBe("cancelled");
    const row = await db.booking.findUnique({ where: { id: hold.id } });
    expect(row?.status).toBe("CANCELLED");
  });

  test("is idempotent — cancelling an already-CANCELLED booking returns alreadyCancelled", async () => {
    const hold = await makeBooking("CANCELLED");
    const result = await cancelBooking(db, {
      bookingId: hold.id,
      cancelledByUserId: customerId,
    });
    expect(result).toEqual({ kind: "cancelled", alreadyCancelled: true });
  });

  test("rejects cancelling a COMPLETED booking", async () => {
    const hold = await makeBooking("COMPLETED");
    const result = await cancelBooking(db, {
      bookingId: hold.id,
      cancelledByUserId: customerId,
    });
    expect(result).toEqual({ kind: "rejected", reason: "completed" });
    const row = await db.booking.findUnique({ where: { id: hold.id } });
    expect(row?.status).toBe("COMPLETED"); // unchanged
  });

  test("rejects cancelling a NO_SHOW booking", async () => {
    const hold = await makeBooking("NO_SHOW");
    const result = await cancelBooking(db, {
      bookingId: hold.id,
      cancelledByUserId: customerId,
    });
    expect(result).toEqual({ kind: "rejected", reason: "no_show" });
  });

  test("after cancelling, the slot becomes bookable again (DB exclusion no longer blocks)", async () => {
    const hold = await makeBooking("CONFIRMED");
    await cancelBooking(db, {
      bookingId: hold.id,
      cancelledByUserId: customerId,
    });
    // Same therapist + same time should now succeed
    const newHold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    expect(newHold.id).toBeTruthy();
    expect(newHold.id).not.toBe(hold.id);
  });

  test("throws on unknown bookingId", async () => {
    await expect(
      cancelBooking(db, {
        bookingId: "no-such-booking",
        cancelledByUserId: customerId,
      }),
    ).rejects.toThrow(/not found/);
  });
});

describe("expireStaleHolds", () => {
  test("expires only HOLDs whose holdExpiresAt is past", async () => {
    // Create one fresh hold (10 min default) and manually backdate another.
    const fresh = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    const stale = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistB,
      roomId: roomB,
      startsAt: D("2026-05-05T16:00:00Z"),
    });
    await db.booking.update({
      where: { id: stale.id },
      data: { holdExpiresAt: new Date(Date.now() - 60_000) },
    });

    const count = await expireStaleHolds(db);
    expect(count).toBe(1);

    const freshRow = await db.booking.findUnique({ where: { id: fresh.id } });
    const staleRow = await db.booking.findUnique({ where: { id: stale.id } });
    expect(freshRow?.status).toBe("HOLD");
    expect(staleRow?.status).toBe("CANCELLED");
    expect(staleRow?.cancelReason).toBe("hold expired");
  });
});

describe("rescheduleBooking", () => {
  test("cancels old + creates new at the new time, atomically", async () => {
    const original = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await confirmHold(db, original.id);

    const result = await rescheduleBooking(db, {
      oldBookingId: original.id,
      newStartsAt: D("2026-05-06T14:00:00Z"),
      cancelledByUserId: customerId,
    });
    expect(result.oldBookingId).toBe(original.id);
    expect(result.newBookingId).not.toBe(original.id);

    const oldRow = await db.booking.findUnique({ where: { id: original.id } });
    const newRow = await db.booking.findUnique({ where: { id: result.newBookingId } });
    expect(oldRow?.status).toBe("CANCELLED");
    expect(oldRow?.cancelReason).toBe("rescheduled");
    expect(newRow?.status).toBe("CONFIRMED");
    expect(newRow?.startsAt).toEqual(D("2026-05-06T14:00:00Z"));
  });

  test("rolls back if the new slot conflicts (old booking stays CONFIRMED)", async () => {
    // Block the target slot with a CONFIRMED booking on therapistA at 11:00.
    const blocker = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-06T15:00:00Z"),
    });
    await confirmHold(db, blocker.id);

    const original = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await confirmHold(db, original.id);

    await expect(
      rescheduleBooking(db, {
        oldBookingId: original.id,
        newStartsAt: D("2026-05-06T15:00:00Z"), // collides with blocker
        cancelledByUserId: customerId,
      }),
    ).rejects.toBeInstanceOf(BookingConflictError);

    // Both bookings unchanged
    const orig = await db.booking.findUnique({ where: { id: original.id } });
    const blk = await db.booking.findUnique({ where: { id: blocker.id } });
    expect(orig?.status).toBe("CONFIRMED");
    expect(blk?.status).toBe("CONFIRMED");
  });

  test("rejects rescheduling a CANCELLED booking", async () => {
    const original = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await cancelBooking(db, {
      bookingId: original.id,
      cancelledByUserId: customerId,
    });
    await expect(
      rescheduleBooking(db, {
        oldBookingId: original.id,
        newStartsAt: D("2026-05-06T14:00:00Z"),
        cancelledByUserId: customerId,
      }),
    ).rejects.toThrow(/Cannot reschedule/);
  });

  test("can change therapist/room/service on reschedule", async () => {
    const original = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await confirmHold(db, original.id);

    const result = await rescheduleBooking(db, {
      oldBookingId: original.id,
      newStartsAt: D("2026-05-06T14:00:00Z"),
      newTherapistId: therapistB,
      newRoomId: roomB,
      cancelledByUserId: customerId,
    });
    const newRow = await db.booking.findUnique({ where: { id: result.newBookingId } });
    expect(newRow?.therapistId).toBe(therapistB);
    expect(newRow?.roomId).toBe(roomB);
  });
});

describe("markComplete / markNoShow", () => {
  test("markComplete: CONFIRMED → COMPLETED", async () => {
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await confirmHold(db, hold.id);
    const result = await markComplete(db, hold.id);
    expect(result.ok).toBe(true);
    const row = await db.booking.findUnique({ where: { id: hold.id } });
    expect(row?.status).toBe("COMPLETED");
  });

  test("markComplete is idempotent", async () => {
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await confirmHold(db, hold.id);
    await markComplete(db, hold.id);
    const second = await markComplete(db, hold.id);
    expect(second.ok).toBe(true);
  });

  test("markComplete rejects HOLD bookings", async () => {
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    const result = await markComplete(db, hold.id);
    expect(result.ok).toBe(false);
    if (!result.ok) expect(result.reason).toMatch(/HOLD/);
  });

  test("markNoShow: CONFIRMED → NO_SHOW", async () => {
    const hold = await createHold(db, {
      customerId,
      serviceId,
      therapistId: therapistA,
      roomId: roomA,
      startsAt: D("2026-05-05T14:00:00Z"),
    });
    await confirmHold(db, hold.id);
    const result = await markNoShow(db, hold.id);
    expect(result.ok).toBe(true);
    const row = await db.booking.findUnique({ where: { id: hold.id } });
    expect(row?.status).toBe("NO_SHOW");
  });
});