package commands

import (
	"fmt"
	"math"
	"sort"
	"strings"
	"unicode/utf8"

	"github.com/Cynosphere/comcord/lib"
	"github.com/Cynosphere/comcord/state"
	"github.com/bwmarrin/discordgo"
)

type GuildListing struct {
  Name string
  Members int
  Online int
}

func ListGuildsCommand(session *discordgo.Session) {
  longest := 0
  guilds := make([]GuildListing, 0)

  for _, guild := range session.State.Guilds {
    length := utf8.RuneCountInString(guild.Name)
    if length > longest {
      longest = length
    }

    guildWithCounts, err := session.GuildWithCounts(guild.ID)
    if err != nil {
      guilds = append(guilds, GuildListing{
        Name: guild.Name,
        Members: guild.MemberCount,
        Online: 0,
      })
      return
    }

    guilds = append(guilds, GuildListing{
      Name: guild.Name,
      Members: guildWithCounts.ApproximateMemberCount,
      Online: guildWithCounts.ApproximatePresenceCount,
    })
  }

  fmt.Print("\n\r")
  fmt.Printf("  %*s  online  total\n\r", longest, "guild-name")
  fmt.Print(strings.Repeat("-", 80) + "\n\r")
  for _, guild := range guilds {
    fmt.Printf("  %*s  %6d  %5d\n\r", longest, guild.Name, guild.Online, guild.Members)
  }
  fmt.Print(strings.Repeat("-", 80) + "\n\r")
  fmt.Print("\n\r")
}

func GetSortedChannels(session *discordgo.Session, guildId string) []*discordgo.Channel {
  channels := make([]*discordgo.Channel, 0)
  guild, err := session.State.Guild(guildId)
  if err != nil {
    return channels
  }

  for _, channel := range guild.Channels {
    if channel.Type != discordgo.ChannelTypeGuildText && channel.Type != discordgo.ChannelTypeGuildNews {
      continue
    }
    channels = append(channels, channel)
  }

  sort.Slice(channels, func(i, j int) bool {
    return channels[i].Position < channels[j].Position
  })

  return channels
}

func ListChannelsCommand(session *discordgo.Session) {
  currentGuild := state.GetCurrentGuild()
  if currentGuild == "" {
    fmt.Print("<not in a guild>\n\r")
    return
  }

  longest := 0
  channels := GetSortedChannels(session, currentGuild)

  for _, channel := range channels {
    perms, err := session.State.UserChannelPermissions(session.State.User.ID, channel.ID)
    if err != nil {
      continue
    }

    private := perms & discordgo.PermissionViewChannel == 0

    privLen := 0
    if private {
      privLen = 1
    }
    length := utf8.RuneCountInString(channel.Name) + privLen

    if length > longest {
      longest = int(math.Min(25, float64(length)))
    }
  }

  fmt.Print("\n\r")
  fmt.Printf("  %*s  topic\n\r", longest, "channel-name")
  fmt.Print(strings.Repeat("-", 80) + "\n\r")
  for _, channel := range channels {
    perms, err := session.State.UserChannelPermissions(session.State.User.ID, channel.ID)
    if err != nil {
      continue
    }

    private := perms & discordgo.PermissionViewChannel == 0
    topic := strings.ReplaceAll(channel.Topic, "\n", " ")
    name := channel.Name
    if private {
      name = "*" + name
    }

    nameLength := utf8.RuneCountInString(name)
    if nameLength > 25 {
      name = name[:24] + "\u2026"
    }

    topicLength := utf8.RuneCountInString(topic)
    longestTopic := 80 - (longest + 5)
    if topicLength > longestTopic {
      topic = topic[:(longestTopic - 1)] + "\u2026"
    }

    fmt.Printf("  %*s  %s\n\r", longest, name, topic)
  }
  fmt.Print(strings.Repeat("-", 80) + "\n\r")
  fmt.Print("\n\r")
}

func ListUsersCommand(session *discordgo.Session) {

}

func SwitchGuild(session *discordgo.Session, input string) {
  if input == "" {
    ListChannelsCommand(session)
    ListUsersCommand(session)
  } else {
    target := ""

    for _, guild := range session.State.Guilds {
      if strings.Index(strings.ToLower(guild.Name), strings.ToLower(input)) > -1 {
        target = guild.ID
        break;
      }
    }

    if target == "" {
      fmt.Print("<guild not found>\n\r")
    } else {
      state.SetCurrentGuild(target)
      last := state.GetLastChannel(target)
      if last == "" {
        channels := GetSortedChannels(session, target)
        topChannel := channels[0]

        state.SetCurrentChannel(topChannel.ID)
        state.SetLastChannel(target, topChannel.ID)
      } else {
        state.SetCurrentChannel(last)
      }

      ListChannelsCommand(session)
      ListUsersCommand(session)

      // TODO: update presence
    }
  }
}

func SwitchGuildsCommand(session *discordgo.Session) {
  lib.MakePrompt(session, ":guild> ", false, func(session *discordgo.Session, input string, interrupt bool) {
    fmt.Print("\r")
    SwitchGuild(session, input)
  })
}