'use strict'

const { isAnnouncementChannel } = require('pearcord-threads')

const announcementsMixin = {
  _announcementFollowHealWatermark: null,
  _announcementCrosspostHealWatermark: null,
  _announcementCrosspostGossipKeys: null,
  _announcementFollowGossipKeys: null,
  _crosspostRateByGuild: null,
  _lastCrosspostPublish: null,

  _initAnnouncementMixinState () {
    if (!this._announcementCrosspostGossipKeys) {
      this._announcementCrosspostGossipKeys = new Set()
    }
    if (!this._announcementFollowGossipKeys) {
      this._announcementFollowGossipKeys = new Set()
    }
    if (!this._crosspostRateByGuild) {
      this._crosspostRateByGuild = new Map()
    }
  },

  _shouldGossipAnnouncementCrosspost (row) {
    this._initAnnouncementMixinState()
    if (!row?.guildId || !row?.sourceChannelId) return true
    const ids = (row.targetChannelIds || []).join(',')
    const hash = `${row.guildId}:${row.sourceChannelId}:${ids}:${row.updatedAt || 0}`
    if (this._announcementCrosspostGossipKeys.has(hash)) return false
    this._announcementCrosspostGossipKeys.add(hash)
    if (this._announcementCrosspostGossipKeys.size > 4096) {
      const first = this._announcementCrosspostGossipKeys.values().next().value
      if (first) this._announcementCrosspostGossipKeys.delete(first)
    }
    return true
  },

  _shouldGossipAnnouncementFollow (row) {
    this._initAnnouncementMixinState()
    if (!row?.guildId || !row?.channelId || !row?.userId) return true
    const hash = `${row.guildId}:${row.channelId}:${row.userId}:${row.active ? '1' : '0'}:${row.updatedAt || 0}`
    if (this._announcementFollowGossipKeys.has(hash)) return false
    this._announcementFollowGossipKeys.add(hash)
    if (this._announcementFollowGossipKeys.size > 8192) {
      const first = this._announcementFollowGossipKeys.values().next().value
      if (first) this._announcementFollowGossipKeys.delete(first)
    }
    return true
  },

  _checkCrosspostPublishRateLimit (guildId) {
    this._initAnnouncementMixinState()
    const gid = guildId || this.guild?.guild?.id
    if (!gid) return true
    const cap = 12
    const windowMs = 60_000
    const now = Date.now()
    let bucket = this._crosspostRateByGuild.get(gid)
    if (!bucket || now >= bucket.resetAt) {
      bucket = { count: 0, resetAt: now + windowMs }
    }
    if (bucket.count >= cap) return false
    bucket.count++
    this._crosspostRateByGuild.set(gid, bucket)
    return true
  },

  async _healAnnouncementCrosspostOnPartition (guildId) {
    const gid = guildId || this.guild?.guild?.id || null
    const span = this.log.time('announcement.heal', {
      spanKind: 'announcement.heal',
      guildId: gid,
      slice: 'crosspost'
    })
    try {
      if (!gid || !this.guild?.listChannels || !this.announcements) {
        span.end({ relisted: 0, skipped: true })
        return { relisted: 0, skipped: true }
      }
      const channels = await this.guild.listChannels().catch(() => [])
      let relisted = 0
      for (const ch of channels) {
        if (!isAnnouncementChannel(ch) || ch.guildId && ch.guildId !== gid) continue
        const targets = await this.announcements.getCrosspostTargets(gid, ch.id)
        const row = {
          guildId: gid,
          sourceChannelId: ch.id,
          targetChannelIds: targets,
          updatedAt: Date.now()
        }
        if (this._shouldGossipAnnouncementCrosspost(row) && this.guild?.gossipAnnouncementCrosspost) {
          this.guild.gossipAnnouncementCrosspost(row)
          relisted++
        }
      }
      const watermark = Date.now()
      this._announcementCrosspostHealWatermark = watermark
      span.end({ relisted, watermark })
      return { relisted, watermark }
    } catch (err) {
      this.log.error('announcement.heal error', {
        guildId: gid,
        slice: 'crosspost',
        error: err?.message || String(err)
      })
      span.fail(err)
      return { relisted: 0, error: err?.message || String(err) }
    }
  },

  async _healAnnouncementFollowsOnPartition (guildId) {
    const gid = guildId || this.guild?.guild?.id || null
    const span = this.log.time('announcement.heal', {
      spanKind: 'announcement.heal',
      guildId: gid,
      slice: 'follow'
    })
    try {
      if (!gid || !this.announcements?.store) {
        span.end({ relisted: 0, skipped: true })
        return { relisted: 0, skipped: true }
      }
      const userId = this.identity?.user?.id
      if (!userId) {
        span.end({ relisted: 0, skipped: true })
        return { relisted: 0, skipped: true }
      }
      const follows = await this.announcements.listMyFollows(userId, gid)
      let relisted = 0
      for (const row of follows) {
        if (row.guildId !== gid) continue
        if (this._shouldGossipAnnouncementFollow(row) && this.guild?.gossipAnnouncementFollow) {
          this.guild.gossipAnnouncementFollow(row)
          relisted++
        }
      }
      const watermark = Date.now()
      this._announcementFollowHealWatermark = watermark
      span.end({ relisted, watermark, followCount: follows.length })
      return { relisted, watermark, followCount: follows.length }
    } catch (err) {
      this.log.error('announcement.heal error', {
        guildId: gid,
        slice: 'follow',
        error: err?.message || String(err)
      })
      span.fail(err)
      return { relisted: 0, error: err?.message || String(err) }
    }
  }
}

module.exports = { announcementsMixin }