import { FastifyPluginAsync } from 'fastify'
import { db } from '../db'

type SlugParam = { Params: { slug: string } }

export interface HkSettings {
  checkout_auto: boolean
  checkout_priority: string
  inspection_after_clean: boolean
  require_completion_photo: boolean
  emergency_close_days: number
  auto_assign: boolean
  auto_assign_strategy: string
}

const DEFAULT_SETTINGS: HkSettings = {
  checkout_auto: true,
  checkout_priority: 'high',
  inspection_after_clean: true,
  require_completion_photo: false,
  emergency_close_days: 1,
  auto_assign: false,
  auto_assign_strategy: 'least_loaded',
}

export async function getHkSettings(hotelId: string): Promise<HkSettings> {
  const { rows } = await db.query(
    'SELECT checkout_auto, checkout_priority, inspection_after_clean, require_completion_photo, emergency_close_days, auto_assign, auto_assign_strategy FROM housekeeping_settings WHERE hotel_id = $1',
    [hotelId],
  )
  return rows[0] ?? DEFAULT_SETTINGS
}

// Pick a housekeeper based on strategy
export async function autoAssignHousekeeper(
  hotelId: string,
  strategy: string,
): Promise<string | null> {
  if (strategy === 'round_robin') {
    // Housekeeper with fewest tasks assigned today
    const { rows } = await db.query(
      `SELECT u.id
         FROM users u
        WHERE u.hotel_id = $1 AND u.role = 'housekeeper' AND u.active = true
        ORDER BY (
          SELECT COUNT(*) FROM housekeeping_tasks t
           WHERE t.assignee_id = u.id
             AND t.created_at::date = CURRENT_DATE
        ) ASC, RANDOM()
        LIMIT 1`,
      [hotelId],
    )
    return rows[0]?.id ?? null
  }

  if (strategy === 'least_loaded') {
    // Housekeeper with fewest active (pending/in_progress) tasks right now
    const { rows } = await db.query(
      `SELECT u.id
         FROM users u
        WHERE u.hotel_id = $1 AND u.role = 'housekeeper' AND u.active = true
        ORDER BY (
          SELECT COUNT(*) FROM housekeeping_tasks t
           WHERE t.assignee_id = u.id
             AND t.status IN ('pending', 'in_progress')
        ) ASC, RANDOM()
        LIMIT 1`,
      [hotelId],
    )
    return rows[0]?.id ?? null
  }

  if (strategy === 'first_free') {
    // Housekeeper who most recently completed a task (or has never had one) and has no active tasks
    const { rows } = await db.query(
      `SELECT u.id
         FROM users u
        WHERE u.hotel_id = $1 AND u.role = 'housekeeper' AND u.active = true
          AND NOT EXISTS (
            SELECT 1 FROM housekeeping_tasks t
             WHERE t.assignee_id = u.id AND t.status IN ('pending', 'in_progress')
          )
        ORDER BY (
          SELECT MAX(t.completed_at) FROM housekeeping_tasks t
           WHERE t.assignee_id = u.id AND t.status = 'done'
        ) DESC NULLS LAST
        LIMIT 1`,
      [hotelId],
    )
    // If nobody is free, fall back to least_loaded
    if (rows[0]) return rows[0].id
    const { rows: fallback } = await db.query(
      `SELECT u.id
         FROM users u
        WHERE u.hotel_id = $1 AND u.role = 'housekeeper' AND u.active = true
        ORDER BY (
          SELECT COUNT(*) FROM housekeeping_tasks t
           WHERE t.assignee_id = u.id AND t.status IN ('pending', 'in_progress')
        ) ASC, RANDOM()
        LIMIT 1`,
      [hotelId],
    )
    return fallback[0]?.id ?? null
  }

  return null
}

const housekeepingSettings: FastifyPluginAsync = async (fastify) => {
  const getHotelId = async (slug: string): Promise<string | null> => {
    const { rows } = await db.query('SELECT id FROM hotels WHERE slug = $1', [slug])
    return rows[0]?.id ?? null
  }

  const canAccess = (userSlug: string | null, role: string, slug: string) =>
    role === 'super_admin' || userSlug === slug

  // GET /api/hotels/:slug/housekeeping-settings
  fastify.get<SlugParam>(
    '/api/hotels/:slug/housekeeping-settings',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })
      return getHkSettings(hotelId)
    },
  )

  // PATCH /api/hotels/:slug/housekeeping-settings
  fastify.patch<SlugParam & { Body: Partial<HkSettings> }>(
    '/api/hotels/:slug/housekeeping-settings',
    { onRequest: [fastify.authenticate] },
    async (request, reply) => {
      const { slug } = request.params
      if (!canAccess(request.user.hotelSlug, request.user.role, slug))
        return reply.code(403).send({ error: 'Forbidden' })
      const hotelId = await getHotelId(slug)
      if (!hotelId) return reply.code(404).send({ error: 'Hotel not found' })

      const {
        checkout_auto, checkout_priority, inspection_after_clean,
        require_completion_photo, emergency_close_days,
        auto_assign, auto_assign_strategy,
      } = request.body
      await db.query(
        `INSERT INTO housekeeping_settings
           (hotel_id, checkout_auto, checkout_priority, inspection_after_clean, require_completion_photo, emergency_close_days, auto_assign, auto_assign_strategy)
         VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
         ON CONFLICT (hotel_id) DO UPDATE SET
           checkout_auto             = COALESCE(EXCLUDED.checkout_auto,             housekeeping_settings.checkout_auto),
           checkout_priority         = COALESCE(EXCLUDED.checkout_priority,         housekeeping_settings.checkout_priority),
           inspection_after_clean    = COALESCE(EXCLUDED.inspection_after_clean,    housekeeping_settings.inspection_after_clean),
           require_completion_photo  = COALESCE(EXCLUDED.require_completion_photo,  housekeeping_settings.require_completion_photo),
           emergency_close_days      = COALESCE(EXCLUDED.emergency_close_days,      housekeeping_settings.emergency_close_days),
           auto_assign               = COALESCE(EXCLUDED.auto_assign,               housekeeping_settings.auto_assign),
           auto_assign_strategy      = COALESCE(EXCLUDED.auto_assign_strategy,      housekeeping_settings.auto_assign_strategy),
           updated_at                = NOW()`,
        [
          hotelId,
          checkout_auto            ?? DEFAULT_SETTINGS.checkout_auto,
          checkout_priority        ?? DEFAULT_SETTINGS.checkout_priority,
          inspection_after_clean   ?? DEFAULT_SETTINGS.inspection_after_clean,
          require_completion_photo ?? DEFAULT_SETTINGS.require_completion_photo,
          emergency_close_days     ?? DEFAULT_SETTINGS.emergency_close_days,
          auto_assign              ?? DEFAULT_SETTINGS.auto_assign,
          auto_assign_strategy     ?? DEFAULT_SETTINGS.auto_assign_strategy,
        ],
      )
      return getHkSettings(hotelId)
    },
  )
}

export default housekeepingSettings