const MessageModel = require('../models/MessageModel')
const { deleteMessagesAndNotify } = require('./expiredMessages')

function parseViewOnce(raw) {
  if (raw == null || raw === '' || raw === false || raw === 'false' || raw === 0) {
    return false
  }
  return raw === true || raw === 'true' || raw === 1 || raw === '1'
}

const VIEW_ONCE_MEDIA = new Set(['image', 'video', 'voice'])

function isViewOnceMediaType(fileType) {
  return VIEW_ONCE_MEDIA.has(fileType)
}

/** Hide file URL for receiver until they open view-once media */
function sanitizeMessageForViewer(message, viewerId) {
  const doc = message._doc ? { ...message._doc } : { ...message }
  const viewer = String(viewerId)
  const sender = String(doc.senderId)
  const receiver = String(doc.receiverId)

  if (!doc.viewOnce || !isViewOnceMediaType(doc.fileType)) {
    return doc
  }

  if (viewer === sender) {
    return doc
  }

  if (viewer === receiver) {
    if (doc.viewOnceOpenedAt) {
      return {
        ...doc,
        file: '',
        viewOnceExpired: true
      }
    }
    return {
      ...doc,
      file: '',
      viewOnceLocked: true
    }
  }

  return doc
}

async function openViewOnceMessage(messageId, userId) {
  const msg = await MessageModel.findById(messageId)
  if (!msg || !msg.viewOnce) {
    return { error: 'پیام یافت نشد', status: 404 }
  }
  if (String(msg.receiverId) !== String(userId)) {
    return { error: 'دسترسی مجاز نیست', status: 403 }
  }
  if (msg.viewOnceOpenedAt) {
    return { error: 'این پیام قبلاً باز شده است', status: 410 }
  }

  msg.viewOnceOpenedAt = new Date()
  await msg.save()

  return {
    message: msg.toObject(),
    file: msg.file,
    fileType: msg.fileType
  }
}

async function completeViewOnceMessage(io, messageId, userId) {
  const msg = await MessageModel.findById(messageId)
  if (!msg || !msg.viewOnce) {
    return { error: 'پیام یافت نشد', status: 404 }
  }

  const uid = String(userId)
  const isReceiver = String(msg.receiverId) === uid
  const isSender = String(msg.senderId) === uid

  if (!isReceiver && !isSender) {
    return { error: 'دسترسی مجاز نیست', status: 403 }
  }

  if (isReceiver && !msg.viewOnceOpenedAt) {
    return { error: 'پیام هنوز باز نشده', status: 400 }
  }

  await deleteMessagesAndNotify(io, [msg], {
    deletedBy: userId,
    reason: 'viewOnce'
  })

  return { deletedIds: [String(msg._id)] }
}

module.exports = {
  parseViewOnce,
  isViewOnceMediaType,
  sanitizeMessageForViewer,
  openViewOnceMessage,
  completeViewOnceMessage
}