import { NOTIFICATION_EVENTS } from '../../../shared/constants/notification-events.js'
import { prisma } from '../lib/prisma.js'

export async function registerUserMessageRoutes(fastify) {
  fastify.get('/api/me/orders/:id/messages', { preHandler: [fastify.authenticate] }, async (request, reply) => {
    const userId = request.user.sub
    const { id } = request.params
    const order = await prisma.order.findFirst({ where: { id, userId } })
    if (!order) return reply.code(404).send({ error: 'Заказ не найден' })
    const items = await prisma.orderMessage.findMany({
      where: { orderId: id },
      orderBy: { createdAt: 'asc' },
    })
    return { items }
  })

  fastify.post('/api/me/orders/:id/messages', { preHandler: [fastify.authenticate] }, async (request, reply) => {
    const userId = request.user.sub
    const { id } = request.params
    const order = await prisma.order.findFirst({ where: { id, userId } })
    if (!order) return reply.code(404).send({ error: 'Заказ не найден' })
    const text = String(request.body?.text || '').trim()
    if (!text) return reply.code(400).send({ error: 'Сообщение пустое' })
    if (text.length > 2000) return reply.code(400).send({ error: 'Сообщение слишком длинное' })
    const msg = await prisma.orderMessage.create({
      data: { orderId: id, authorType: 'user', text },
    })

    request.server.eventBus.emit(NOTIFICATION_EVENTS.ORDER_MESSAGE_SENT, {
      orderId: id,
      authorType: 'user',
      messageId: msg.id,
      preview: text,
    })

    return reply.code(201).send({ item: msg })
  })

  fastify.get('/api/me/messages/unread-count', { preHandler: [fastify.authenticate] }, async (request) => {
    const userId = request.user.sub
    const orders = await prisma.order.findMany({
      where: { userId },
      select: { id: true },
    })
    if (orders.length === 0) return { count: 0 }

    const orderIds = orders.map((o) => o.id)
    const readStates = await prisma.userOrderMessageReadState.findMany({
      where: { userId },
    })
    const lastReadByOrder = new Map(readStates.map((r) => [r.orderId, r.lastReadAt]))

    const adminMessages = await prisma.orderMessage.findMany({
      where: { orderId: { in: orderIds }, authorType: 'admin' },
      select: { orderId: true, createdAt: true },
    })

    let count = 0
    for (const msg of adminMessages) {
      const lastRead = lastReadByOrder.get(msg.orderId) ?? new Date(0)
      if (msg.createdAt > lastRead) count++
    }
    return { count }
  })

  fastify.get('/api/me/conversations', { preHandler: [fastify.authenticate] }, async (request) => {
    const userId = request.user.sub
    const orders = await prisma.order.findMany({
      where: { userId, messages: { some: {} } },
      select: {
        id: true,
        status: true,
        deliveryType: true,
        messages: {
          orderBy: { createdAt: 'desc' },
          take: 1,
          select: { text: true, createdAt: true },
        },
      },
      orderBy: { updatedAt: 'desc' },
    })

    const readStates = await prisma.userOrderMessageReadState.findMany({
      where: { userId },
    })
    const lastReadByOrder = new Map(readStates.map((r) => [r.orderId, r.lastReadAt]))

    const orderIds = orders.map((o) => o.id)
    const unreadCounts = new Map()
    if (orderIds.length > 0) {
      const adminMessages = await prisma.orderMessage.findMany({
        where: { orderId: { in: orderIds }, authorType: 'admin' },
        select: { orderId: true, createdAt: true },
      })
      for (const msg of adminMessages) {
        const lastRead = lastReadByOrder.get(msg.orderId) ?? new Date(0)
        if (msg.createdAt > lastRead) {
          unreadCounts.set(msg.orderId, (unreadCounts.get(msg.orderId) ?? 0) + 1)
        }
      }
    }

    const items = []
    for (const o of orders) {
      const lastMsg = o.messages[0]
      if (!lastMsg) continue
      items.push({
        orderId: o.id,
        status: o.status,
        deliveryType: o.deliveryType,
        lastMessageAt: lastMsg.createdAt,
        preview: lastMsg.text.length > 280 ? `${lastMsg.text.slice(0, 277)}…` : lastMsg.text,
        unreadCount: unreadCounts.get(o.id) ?? 0,
      })
    }
    return { items }
  })

  fastify.post('/api/me/orders/:id/messages/read', { preHandler: [fastify.authenticate] }, async (request, reply) => {
    const userId = request.user.sub
    const { id } = request.params
    const order = await prisma.order.findFirst({ where: { id, userId } })
    if (!order) return reply.code(404).send({ error: 'Заказ не найден' })

    const now = new Date()
    await prisma.userOrderMessageReadState.upsert({
      where: { userId_orderId: { userId, orderId: id } },
      create: { userId, orderId: id, lastReadAt: now },
      update: { lastReadAt: now },
    })
    return { ok: true }
  })
}