import { Router } from "express";
import { db } from "../db.ts";
import type { AuthedRequest } from "../lib/auth.ts";
import { err } from "../lib/auth.ts";

export const appointmentsRouter = Router();

/** Compute commission for a ticket: service rate, fallback employee rate. */
function computeCommission(businessId: number, serviceId: number, employeeId: number, amount: number): number {
  const svc = db.prepare(`SELECT commission_pct p FROM services WHERE id = ? AND business_id = ?`).get(serviceId, businessId) as { p: number } | undefined;
  let pct = svc?.p ?? 0;
  if (!pct) {
    const emp = db.prepare(`SELECT commission_pct p FROM employees WHERE id = ? AND business_id = ?`).get(employeeId, businessId) as { p: number } | undefined;
    pct = emp?.p ?? 0;
  }
  return Math.round(((amount * pct) / 100) * 100) / 100;
}

function joinAppointment(a: any) {
  if (!a) return a;
  a.service = db
    .prepare(`SELECT id, name, category, color, duration_min, price FROM services WHERE id = ?`)
    .get(a.service_id);
  a.employee = db
    .prepare(`SELECT id, name, color, role FROM employees WHERE id = ?`)
    .get(a.employee_id);
  a.client = db
    .prepare(`SELECT id, name, phone, email, tags FROM clients WHERE id = ?`)
    .get(a.client_id);
  return a;
}

appointmentsRouter.get("/", (req: AuthedRequest, res) => {
  const { from, to, employee_id, client_id, status, limit } = req.query;
  const conds: string[] = ["business_id = ?"];
  const args: any[] = [req.user!.business_id];
  if (from) {
    conds.push("start_at >= ?");
    args.push(String(from));
  }
  if (to) {
    conds.push("start_at <= ?");
    args.push(String(to));
  }
  if (employee_id) {
    conds.push("employee_id = ?");
    args.push(Number(employee_id));
  }
  if (client_id) {
    conds.push("client_id = ?");
    args.push(Number(client_id));
  }
  if (status) {
    conds.push("status = ?");
    args.push(String(status));
  }
  // Employees only see their own appointments (still can see all to plan, but filter by default)
  // We let them see all so they can coordinate; UI filters by default.
  let sql = `SELECT * FROM appointments WHERE ${conds.join(" AND ")} ORDER BY start_at`;
  if (limit) sql += ` LIMIT ${Number(limit)}`;
  const rows = db.prepare(sql).all(...args) as any[];
  rows.forEach(joinAppointment);
  res.json({ appointments: rows });
});

appointmentsRouter.get("/:id", (req: AuthedRequest, res) => {
  const a = db
    .prepare(`SELECT * FROM appointments WHERE id = ? AND business_id = ?`)
    .get(Number(req.params.id), req.user!.business_id) as any;
  if (!a) return err(res, 404, "Cita no encontrada");
  joinAppointment(a);
  res.json({ appointment: a });
});

appointmentsRouter.post("/", (req: AuthedRequest, res) => {
  const {
    service_id,
    employee_id,
    client_id,
    new_client,
    start_at,
    duration_min,
    price_override,
    notes,
    status,
  } = req.body ?? {};

  if (!service_id) return err(res, 400, "Selecciona un servicio");
  if (!start_at) return err(res, 400, "Selecciona una fecha y hora");

  const service = db
    .prepare(`SELECT * FROM services WHERE id = ? AND business_id = ?`)
    .get(Number(service_id), req.user!.business_id) as any;
  if (!service) return err(res, 400, "Servicio no válido");

  // Resolve client: existing id, or create a new one from new_client payload
  let clientId = client_id ? Number(client_id) : null;
  if (!clientId && new_client) {
    if (!new_client.name) return err(res, 400, "El nombre del cliente es obligatorio");
    const created = db
      .prepare(
        `INSERT INTO clients (business_id, name, email, phone, notes, tags) VALUES (?, ?, ?, ?, ?, ?) RETURNING id`
      )
      .get(
        req.user!.business_id,
        new_client.name,
        new_client.email || null,
        new_client.phone || null,
        new_client.notes || null,
        new_client.tags || null
      ) as { id: number };
    clientId = created.id;
  }
  if (!clientId) return err(res, 400, "Selecciona o crea un cliente");

  // Resolve employee: auto-assign to self for employees; default to first eligible for owner
  let empId = employee_id ? Number(employee_id) : null;
  if (!empId && req.user!.role === "employee" && req.user!.employee_id) {
    empId = req.user!.employee_id;
  }
  if (!empId) {
    const eligible = db
      .prepare(`SELECT employee_id id FROM employee_services WHERE service_id = ? LIMIT 1`)
      .get(Number(service_id)) as { id: number } | undefined;
    empId = eligible?.id ?? null;
  }
  if (!empId) return err(res, 400, "No hay empleado asignado a este servicio");

  const start = new Date(start_at);
  if (isNaN(start.getTime())) return err(res, 400, "Fecha de inicio inválida");
  const dur = Number(duration_min) || service.duration_min;
  const end = new Date(start.getTime() + dur * 60000);
  const endIso = end.toISOString().replace(/\.\d{3}Z$/, "Z");
  const startIso = start.toISOString().replace(/\.\d{3}Z$/, "Z");

  const finalStatus = status || "scheduled";
  const price = price_override !== undefined ? Number(price_override) : service.price;

  const r = db
    .prepare(
      `INSERT INTO appointments
        (business_id, service_id, employee_id, client_id, start_at, end_at, status, price, notes, created_by_user_id)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?) RETURNING *`
    )
    .get(
      req.user!.business_id,
      Number(service_id),
      empId,
      clientId,
      startIso,
      endIso,
      finalStatus,
      price,
      notes || null,
      req.user!.id
    ) as any;

  if (finalStatus === "completed") {
    db.prepare(
      `INSERT INTO tickets (business_id, appointment_id, client_id, employee_id, service_id, amount, tip, payment_method)
       VALUES (?, ?, ?, ?, ?, ?, 0, 'card')`
    ).run(req.user!.business_id, r.id, clientId, empId, Number(service_id), price);
  }

  joinAppointment(r);
  res.status(201).json({ appointment: r });
});

appointmentsRouter.patch("/:id", (req: AuthedRequest, res) => {
  const id = Number(req.params.id);
  const existing = db
    .prepare(`SELECT * FROM appointments WHERE id = ? AND business_id = ?`)
    .get(id, req.user!.business_id) as any;
  if (!existing) return err(res, 404, "Cita no encontrada");

  const {
    service_id,
    employee_id,
    client_id,
    start_at,
    end_at,
    duration_min,
    status,
    price,
    notes,
  } = req.body ?? {};

  let startIso = existing.start_at;
  let endIso = existing.end_at;
  if (start_at) {
    const start = new Date(start_at);
    if (isNaN(start.getTime())) return err(res, 400, "Fecha inválida");
    startIso = start.toISOString().replace(/\.\d{3}Z$/, "Z");
    const svc = service_id
      ? db.prepare(`SELECT duration_min FROM services WHERE id = ?`).get(Number(service_id)) as any
      : { duration_min: null };
    const dur = Number(duration_min) || svc?.duration_min || null;
    if (end_at) {
      endIso = new Date(end_at).toISOString().replace(/\.\d{3}Z$/, "Z");
    } else if (dur) {
      endIso = new Date(start.getTime() + dur * 60000).toISOString().replace(/\.\d{3}Z$/, "Z");
    }
  } else if (duration_min) {
    const start = new Date(existing.start_at);
    endIso = new Date(start.getTime() + Number(duration_min) * 60000).toISOString().replace(/\.\d{3}Z$/, "Z");
  }

  const finalStatus = status ?? existing.status;
  const finalPrice = price !== undefined ? Number(price) : existing.price;

  db.prepare(
    `UPDATE appointments
     SET service_id = ?, employee_id = ?, client_id = ?, start_at = ?, end_at = ?, status = ?, price = ?, notes = ?, updated_at = datetime('now')
     WHERE id = ?`
  ).run(
    service_id !== undefined ? Number(service_id) : existing.service_id,
    employee_id !== undefined ? Number(employee_id) : existing.employee_id,
    client_id !== undefined ? Number(client_id) : existing.client_id,
    startIso,
    endIso,
    finalStatus,
    finalPrice,
    notes !== undefined ? notes : existing.notes,
    id
  );

  // If transitioned to completed and no ticket yet, create one
  if (finalStatus === "completed" && existing.status !== "completed") {
    const hasTicket = db
      .prepare(`SELECT id FROM tickets WHERE appointment_id = ?`)
      .get(id);
    if (!hasTicket) {
      const appt = db.prepare(`SELECT * FROM appointments WHERE id = ?`).get(id) as any;
      const commission = computeCommission(appt.business_id, appt.service_id, appt.employee_id, appt.price);
      db.prepare(
        `INSERT INTO tickets (business_id, appointment_id, client_id, employee_id, service_id, amount, tip, payment_method, commission)
         VALUES (?, ?, ?, ?, ?, ?, 0, 'card', ?)`
      ).run(appt.business_id, id, appt.client_id, appt.employee_id, appt.service_id, appt.price, commission);
    }
  }

  const updated = db.prepare(`SELECT * FROM appointments WHERE id = ?`).get(id) as any;
  joinAppointment(updated);
  res.json({ appointment: updated });
});

appointmentsRouter.post("/:id/complete", (req: AuthedRequest, res) => {
  const id = Number(req.params.id);
  const appt = db
    .prepare(`SELECT * FROM appointments WHERE id = ? AND business_id = ?`)
    .get(id, req.user!.business_id) as any;
  if (!appt) return err(res, 404, "Cita no encontrada");
  const { tip = 0, payment_method = "card" } = req.body ?? {};
  db.prepare(`UPDATE appointments SET status = 'completed', updated_at = datetime('now') WHERE id = ?`).run(id);
  const hasTicket = db.prepare(`SELECT id FROM tickets WHERE appointment_id = ?`).get(id);
  if (!hasTicket) {
    const commission = computeCommission(appt.business_id, appt.service_id, appt.employee_id, appt.price);
    db.prepare(
      `INSERT INTO tickets (business_id, appointment_id, client_id, employee_id, service_id, amount, tip, payment_method, commission)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`
    ).run(appt.business_id, id, appt.client_id, appt.employee_id, appt.service_id, appt.price, Number(tip), payment_method, commission);
  } else {
    // ticket already exists (e.g. completed via PATCH) — backfill commission + tip if provided
    db.prepare(`UPDATE tickets SET commission = COALESCE(NULLIF(commission,0), ?) WHERE appointment_id = ? AND commission = 0`).run(
      computeCommission(appt.business_id, appt.service_id, appt.employee_id, appt.price),
      id
    );
  }
  const updated = db.prepare(`SELECT * FROM appointments WHERE id = ?`).get(id) as any;
  joinAppointment(updated);
  res.json({ appointment: updated });
});

appointmentsRouter.delete("/:id", (req: AuthedRequest, res) => {
  const id = Number(req.params.id);
  const existing = db
    .prepare(`SELECT id FROM appointments WHERE id = ? AND business_id = ?`)
    .get(id, req.user!.business_id);
  if (!existing) return err(res, 404, "Cita no encontrada");
  db.prepare(`DELETE FROM appointments WHERE id = ?`).run(id);
  res.json({ ok: true });
});

/** Preview the cancellation policy outcome for an appointment (penalty based on hours left). */
appointmentsRouter.get("/:id/cancellation-policy", (req: AuthedRequest, res) => {
  const id = Number(req.params.id);
  const appt = db.prepare(`SELECT * FROM appointments WHERE id = ? AND business_id = ?`).get(id, req.user!.business_id) as any;
  if (!appt) return err(res, 404, "Cita no encontrada");
  const biz = db
    .prepare(`SELECT cancel_window_hours wh, cancel_penalty_pct pen, require_deposit rd, deposit_pct dp FROM businesses WHERE id = ?`)
    .get(req.user!.business_id) as any;
  const hoursLeft = (new Date(appt.start_at).getTime() - Date.now()) / 3600000;
  const withinWindow = hoursLeft < (biz?.wh ?? 24);
  const penalty = withinWindow ? Math.round(((appt.price * (biz?.pen ?? 0)) / 100) * 100) / 100 : 0;
  res.json({
    hours_left: Math.round(hoursLeft),
    within_window: withinWindow,
    window_hours: biz?.wh ?? 24,
    penalty_pct: withinWindow ? biz?.pen ?? 0 : 0,
    penalty_amount: penalty,
    policy_active: (biz?.pen ?? 0) > 0,
  });
});