import Joi from 'joi';
import Boom from '@hapi/boom';
import { credentials, authResponse } from '../plugins/auth.js';
import { env } from '../config/env.js';
import { User } from '../models/User.js';
import {
  applyGoogleTokens,
  createCalendarEvent,
  disconnectGoogle,
  exchangeCode,
  getConnectUrl,
  googleConfigured,
  signConnectState,
  verifyConnectState,
} from '../services/google.js';

function pad(n) {
  return String(n).padStart(2, '0');
}

function combineDateTime(date, time) {
  const normalized = time.length === 5 ? `${time}:00` : time;
  return `${date}T${normalized}`;
}

function addOneHour(date, time) {
  const [year, month, day] = date.split('-').map(Number);
  const [hours, minutes] = time.split(':').map(Number);
  const dt = new Date(year, month - 1, day, hours, minutes);
  dt.setHours(dt.getHours() + 1);
  return {
    date: `${dt.getFullYear()}-${pad(dt.getMonth() + 1)}-${pad(dt.getDate())}`,
    time: `${pad(dt.getHours())}:${pad(dt.getMinutes())}`,
  };
}

function eventRange({ date, startTime, endTime }) {
  const start = combineDateTime(date, startTime);
  let endDate = date;
  let resolvedEnd = endTime;
  if (!resolvedEnd) {
    const next = addOneHour(date, startTime);
    endDate = next.date;
    resolvedEnd = next.time;
  }
  let end = combineDateTime(endDate, resolvedEnd);
  if (end <= start) {
    const [year, month, day] = date.split('-').map(Number);
    const nextDay = new Date(year, month - 1, day + 1);
    end = combineDateTime(`${nextDay.getFullYear()}-${pad(nextDay.getMonth() + 1)}-${pad(nextDay.getDate())}`, resolvedEnd);
  }
  return { start, end };
}

function profileRedirect(status) {
  return `${env.APP_URL}/profile?google=${encodeURIComponent(status)}`;
}

export function googleRoutes(server) {
  server.route({
    method: 'GET',
    path: '/api/google/connect',
    handler: async (request) => {
      if (!googleConfigured()) throw Boom.badRequest('Google Calendar is not configured');
      const { user } = credentials(request);
      return { url: getConnectUrl(signConnectState(user._id)) };
    },
  });

  server.route({
    method: 'GET',
    path: '/api/google/callback',
    options: {
      auth: false,
      validate: {
        query: Joi.object({
          code: Joi.string().allow(''),
          state: Joi.string().allow(''),
          error: Joi.string().allow(''),
          scope: Joi.string().allow(''),
        }).unknown(true),
      },
    },
    handler: async (request, h) => {
      const { code, state, error } = request.query;
      if (error || !code || !state) return h.redirect(profileRedirect('error'));
      const userId = verifyConnectState(state);
      if (!userId) return h.redirect(profileRedirect('error'));
      try {
        const user = await User.findById(userId);
        if (!user || !user.isActive) return h.redirect(profileRedirect('error'));
        const { tokens, profile } = await exchangeCode(code);
        applyGoogleTokens(user, tokens, profile);
        await user.save();
        return h.redirect(profileRedirect('connected'));
      } catch {
        return h.redirect(profileRedirect('error'));
      }
    },
  });

  server.route({
    method: 'POST',
    path: '/api/google/events',
    options: {
      validate: {
        payload: Joi.object({
          title: Joi.string().trim().min(1).max(200).required(),
          date: Joi.string().pattern(/^\d{4}-\d{2}-\d{2}$/).required(),
          startTime: Joi.string().pattern(/^\d{2}:\d{2}$/).required(),
          endTime: Joi.string().pattern(/^\d{2}:\d{2}$/).allow('', null),
          timeZone: Joi.string().trim().min(1).max(100).allow('', null),
          autoAdmit: Joi.boolean().default(true),
          allowMicVideo: Joi.boolean().default(true),
        }),
      },
    },
    handler: async (request) => {
      const { user } = credentials(request);
      const fresh = await User.findById(user._id);
      if (!fresh || !fresh.isActive) throw Boom.unauthorized();
      if (!fresh.google?.refreshToken && !fresh.google?.accessToken) {
        throw Boom.badRequest('Connect Google Calendar first');
      }
      const { title, date, startTime, endTime, timeZone, autoAdmit, allowMicVideo } = request.payload;
      const { start, end } = eventRange({ date, startTime, endTime });
      return createCalendarEvent(fresh, {
        title,
        start,
        end,
        timeZone: timeZone || 'UTC',
        autoAdmit,
        allowMicVideo,
      });
    },
  });

  server.route({
    method: 'POST',
    path: '/api/google/disconnect',
    handler: async (request) => {
      const { user } = credentials(request);
      const fresh = await User.findById(user._id).populate('role');
      if (!fresh || !fresh.isActive) throw Boom.unauthorized();
      await disconnectGoogle(fresh);
      await fresh.populate('role');
      const { token, ...rest } = authResponse(fresh, 'unused');
      return rest;
    },
  });
}