// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2020 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package ui

import (
	"encoding/json"
	"fmt"
	"io"
	"math"
	"os"
	"regexp"
	"runtime"
	dbg "runtime/debug"
	"runtime/pprof"
	"runtime/trace"
	"strconv"
	"strings"
	"time"
	"unicode"

	"github.com/lucasb-eyer/go-colorful"
	"github.com/russross/blackfriday/v2"

	"maunium.net/go/mautrix"
	"maunium.net/go/mautrix/event"
	"maunium.net/go/mautrix/format"
	"maunium.net/go/mautrix/id"

	"maunium.net/go/gomuks/debug"
)

func cmdMe(cmd *Command) {
	text := strings.Join(cmd.Args, " ")
	go cmd.Room.SendMessage(event.MsgEmote, text)
}

// GradientTable from https://github.com/lucasb-eyer/go-colorful/blob/master/doc/gradientgen/gradientgen.go
type GradientTable []struct {
	Col colorful.Color
	Pos float64
}

func (gt GradientTable) GetInterpolatedColorFor(t float64) colorful.Color {
	for i := 0; i < len(gt)-1; i++ {
		c1 := gt[i]
		c2 := gt[i+1]
		if c1.Pos <= t && t <= c2.Pos {
			t := (t - c1.Pos) / (c2.Pos - c1.Pos)
			return c1.Col.BlendHcl(c2.Col, t).Clamped()
		}
	}
	return gt[len(gt)-1].Col
}

var rainbow = GradientTable{
	{colorful.LinearRgb(1, 0, 0), 0 / 11.0},
	{colorful.LinearRgb(1, 0.5, 0), 1 / 11.0},
	{colorful.LinearRgb(1, 1, 0), 2 / 11.0},
	{colorful.LinearRgb(0.5, 1, 0), 3 / 11.0},
	{colorful.LinearRgb(0, 1, 0), 4 / 11.0},
	{colorful.LinearRgb(0, 1, 0.5), 5 / 11.0},
	{colorful.LinearRgb(0, 1, 1), 6 / 11.0},
	{colorful.LinearRgb(0, 0.5, 1), 7 / 11.0},
	{colorful.LinearRgb(0, 0, 1), 8 / 11.0},
	{colorful.LinearRgb(0.5, 0, 1), 9 / 11.0},
	{colorful.LinearRgb(1, 0, 1), 10 / 11.0},
	{colorful.LinearRgb(1, 0, 0.5), 11 / 11.0},
}

// TODO this command definitely belongs in a plugin once we have a plugin system.
func makeRainbow(cmd *Command, msgtype event.MessageType) {
	text := strings.Join(cmd.Args, " ")

	render := NewRainbowRenderer(blackfriday.NewHTMLRenderer(blackfriday.HTMLRendererParameters{
		Flags: blackfriday.UseXHTML,
	}))
	htmlBodyBytes := blackfriday.Run([]byte(text), format.Extensions, blackfriday.WithRenderer(render))
	htmlBody := strings.TrimRight(string(htmlBodyBytes), "\n")
	htmlBody = format.AntiParagraphRegex.ReplaceAllString(htmlBody, "$1")
	text = format.HTMLToText(htmlBody)

	count := strings.Count(htmlBody, render.ColorID)
	i := -1
	htmlBody = regexp.MustCompile(render.ColorID).ReplaceAllStringFunc(htmlBody, func(match string) string {
		i++
		return rainbow.GetInterpolatedColorFor(float64(i) / float64(count)).Hex()
	})

	go cmd.Room.SendMessageHTML(msgtype, text, htmlBody)
}

func cmdRainbow(cmd *Command) {
	makeRainbow(cmd, event.MsgText)
}

func cmdRainbowMe(cmd *Command) {
	makeRainbow(cmd, event.MsgEmote)
}

func cmdNotice(cmd *Command) {
	go cmd.Room.SendMessage(event.MsgNotice, strings.Join(cmd.Args, " "))
}

func cmdAccept(cmd *Command) {
	room := cmd.Room.MxRoom()
	if room.SessionMember.Membership != "invite" {
		cmd.Reply("/accept can only be used in rooms you're invited to")
		return
	}
	_, server, _ := room.SessionMember.Sender.Parse()
	_, err := cmd.Matrix.JoinRoom(room.ID, server)
	if err != nil {
		cmd.Reply("Failed to accept invite:", err)
	} else {
		cmd.Reply("Successfully accepted invite")
	}
	cmd.MainView.UpdateTags(room)
	go cmd.MainView.LoadHistory(room.ID)
}

func cmdReject(cmd *Command) {
	room := cmd.Room.MxRoom()
	if room.SessionMember.Membership != "invite" {
		cmd.Reply("/reject can only be used in rooms you're invited to")
		return
	}
	err := cmd.Matrix.LeaveRoom(room.ID)
	if err != nil {
		cmd.Reply("Failed to reject invite: %v", err)
	} else {
		cmd.Reply("Successfully accepted invite")
	}
}

func cmdID(cmd *Command) {
	cmd.Reply("The internal ID of this room is %s", cmd.Room.MxRoom().ID)
}

type SelectReason string

const (
	SelectReply    SelectReason = "reply to"
	SelectReact                 = "react to"
	SelectRedact                = "redact"
	SelectDownload              = "download"
	SelectOpen                  = "open"
)

func cmdReply(cmd *Command) {
	cmd.Room.StartSelecting(SelectReply, strings.Join(cmd.Args, " "))
}

func cmdRedact(cmd *Command) {
	cmd.Room.StartSelecting(SelectRedact, strings.Join(cmd.Args, " "))
}

func cmdDownload(cmd *Command) {
	cmd.Room.StartSelecting(SelectDownload, strings.Join(cmd.Args, " "))
}

func cmdOpen(cmd *Command) {
	cmd.Room.StartSelecting(SelectOpen, strings.Join(cmd.Args, " "))
}

func cmdReact(cmd *Command) {
	if len(cmd.Args) == 0 {
		cmd.Reply("Usage: /react <reaction>")
		return
	}

	cmd.Room.StartSelecting(SelectReact, strings.Join(cmd.Args, " "))
}

func cmdTags(cmd *Command) {
	tags := cmd.Room.MxRoom().RawTags
	if len(cmd.Args) > 0 && cmd.Args[0] == "--internal" {
		tags = cmd.Room.MxRoom().Tags()
	}
	if len(tags) == 0 {
		if cmd.Room.MxRoom().IsDirect {
			cmd.Reply("This room has no tags, but it's marked as a direct chat.")
		} else {
			cmd.Reply("This room has no tags.")
		}
		return
	}
	var resp strings.Builder
	resp.WriteString("Tags in this room:\n")
	for _, tag := range tags {
		if tag.Order != "" {
			_, _ = fmt.Fprintf(&resp, "%s (order: %s)\n", tag.Tag, tag.Order)
		} else {
			_, _ = fmt.Fprintf(&resp, "%s (no order)\n", tag.Tag)
		}
	}
	cmd.Reply(strings.TrimSpace(resp.String()))
}

func cmdTag(cmd *Command) {
	if len(cmd.Args) == 0 {
		cmd.Reply("Usage: /tag <tag> [order]")
		return
	}
	order := math.NaN()
	if len(cmd.Args) > 1 {
		var err error
		order, err = strconv.ParseFloat(cmd.Args[1], 64)
		if err != nil {
			cmd.Reply("%s is not a valid order: %v", cmd.Args[1], err)
			return
		}
	}
	var err error
	if len(cmd.Args) > 2 && cmd.Args[2] == "--reset" {
		tags := event.Tags{
			cmd.Args[0]: {Order: json.Number(fmt.Sprintf("%f", order))},
		}
		for _, tag := range cmd.Room.MxRoom().RawTags {
			tags[tag.Tag] = event.Tag{Order: tag.Order}
		}
		err = cmd.Matrix.Client().SetTags(cmd.Room.MxRoom().ID, tags)
	} else {
		err = cmd.Matrix.Client().AddTag(cmd.Room.MxRoom().ID, cmd.Args[0], order)
	}
	if err != nil {
		cmd.Reply("Failed to add tag:", err)
	}
}

func cmdUntag(cmd *Command) {
	if len(cmd.Args) == 0 {
		cmd.Reply("Usage: /untag <tag>")
		return
	}
	err := cmd.Matrix.Client().RemoveTag(cmd.Room.MxRoom().ID, cmd.Args[0])
	if err != nil {
		cmd.Reply("Failed to remove tag:", err)
	}
}

func cmdRoomNick(cmd *Command) {
	room := cmd.Room.MxRoom()
	member := room.GetMember(room.SessionUserID)
	member.Displayname = strings.Join(cmd.Args, " ")
	_, err := cmd.Matrix.Client().SendStateEvent(room.ID, event.StateMember, string(room.SessionUserID), member)
	if err != nil {
		cmd.Reply("Failed to set room nick:", err)
	}
}

func cmdHeapProfile(cmd *Command) {
	runtime.GC()
	dbg.FreeOSMemory()
	memProfile, err := os.Create("gomuks.heap.prof")
	if err != nil {
		debug.Print("Failed to open gomuks.heap.prof:", err)
		return
	}
	defer func() {
		err := memProfile.Close()
		if err != nil {
			debug.Print("Failed to close gomuks.heap.prof:", err)
		}
	}()
	if err := pprof.WriteHeapProfile(memProfile); err != nil {
		debug.Print("Heap profile error:", err)
	}
}

func runTimedProfile(cmd *Command, start func(writer io.Writer) error, stop func(), task, file string) {
	if len(cmd.Args) == 0 {
		cmd.Reply("Usage: /%s <seconds>", cmd.Command)
	} else if dur, err := strconv.Atoi(cmd.Args[0]); err != nil || dur < 0 {
		cmd.Reply("Usage: /%s <seconds>", cmd.Command)
	} else if cpuProfile, err := os.Create(file); err != nil {
		debug.Printf("Failed to open %s: %v", file, err)
	} else if err = start(cpuProfile); err != nil {
		_ = cpuProfile.Close()
		debug.Print(task, "error:", err)
	} else {
		cmd.Reply("Started %s for %d seconds", task, dur)
		go func() {
			time.Sleep(time.Duration(dur) * time.Second)
			stop()
			cmd.Reply("%s finished.", task)

			err := cpuProfile.Close()
			if err != nil {
				debug.Print("Failed to close gomuks.cpu.prof:", err)
			}
		}()
	}
}

func cmdCPUProfile(cmd *Command) {
	runTimedProfile(cmd, pprof.StartCPUProfile, pprof.StopCPUProfile, "CPU profiling", "gomuks.cpu.prof")
}

func cmdTrace(cmd *Command) {
	runTimedProfile(cmd, trace.Start, trace.Stop, "Call tracing", "gomuks.trace")
}

func cmdQuit(cmd *Command) {
	cmd.Gomuks.Stop(true)
}

func cmdClearCache(cmd *Command) {
	cmd.Config.Clear()
	cmd.Gomuks.Stop(false)
}

func cmdUnknownCommand(cmd *Command) {
	cmd.Reply("Unknown command \"%s\". Try \"/help\" for help.", cmd.Command)
}

func cmdHelp(cmd *Command) {
	cmd.Reply(`# General
/help           - Show this "temporary" help message.
/quit           - Quit gomuks.
/clearcache     - Clear cache and quit gomuks.
/logout         - Log out of Matrix.
/toggle <thing> - Temporary command to toggle various UI features.

Things: rooms, users, baremessages, images, typingnotif

# Sending special messages
/me <message>        - Send an emote message.
/notice <message>    - Send a notice (generally used for bot messages).
/rainbow <message>   - Send rainbow text (markdown not supported).
/rainbowme <message> - Send rainbow text in an emote.
/reply [text]        - Reply to the selected message.
/react <reaction>    - React to the selected message.
/redact [reason]    - Redact the selected message.

# Rooms
/pm <user id> <...>   - Create a private chat with the given user(s).
/create [room name]   - Create a room.

/join <room> [server] - Join a room.
/accept               - Accept the invite.
/reject               - Reject the invite.

/invite <user id>     - Invite the given user to the room.
/roomnick <name>      - Change your per-room displayname.
/tag <tag> <priority> - Add the room to <tag>.
/untag <tag>          - Remove the room from <tag>.
/tags                 - List the tags the room is in.

/leave                     - Leave the current room.
/kick   <user id> [reason] - Kick a user.
/ban    <user id> [reason] - Ban a user.
/unban  <user id>          - Unban a user.`)
}

func cmdLeave(cmd *Command) {
	err := cmd.Matrix.LeaveRoom(cmd.Room.MxRoom().ID)
	debug.Print("Leave room error:", err)
	if err == nil {
		cmd.MainView.RemoveRoom(cmd.Room.MxRoom())
	}
}

func cmdInvite(cmd *Command) {
	if len(cmd.Args) != 1 {
		cmd.Reply("Usage: /invite <user id>")
		return
	}
	_, err := cmd.Matrix.Client().InviteUser(cmd.Room.MxRoom().ID, &mautrix.ReqInviteUser{UserID: id.UserID(cmd.Args[0])})
	if err != nil {
		debug.Print("Error in invite call:", err)
		cmd.Reply("Failed to invite user: %v", err)
	}
}

func cmdBan(cmd *Command) {
	if len(cmd.Args) < 1 {
		cmd.Reply("Usage: /ban <user> [reason]")
		return
	}
	reason := "you are the weakest link, goodbye!"
	if len(cmd.Args) >= 2 {
		reason = strings.Join(cmd.Args[1:], " ")
	}
	_, err := cmd.Matrix.Client().BanUser(cmd.Room.MxRoom().ID, &mautrix.ReqBanUser{Reason: reason, UserID: id.UserID(cmd.Args[0])})
	if err != nil {
		debug.Print("Error in ban call:", err)
		cmd.Reply("Failed to ban user: %v", err)
	}

}

func cmdUnban(cmd *Command) {
	if len(cmd.Args) != 1 {
		cmd.Reply("Usage: /unban <user>")
		return
	}
	_, err := cmd.Matrix.Client().UnbanUser(cmd.Room.MxRoom().ID, &mautrix.ReqUnbanUser{UserID: id.UserID(cmd.Args[0])})
	if err != nil {
		debug.Print("Error in unban call:", err)
		cmd.Reply("Failed to unban user: %v", err)
	}
}

func cmdKick(cmd *Command) {
	if len(cmd.Args) < 1 {
		cmd.Reply("Usage: /kick <user> [reason]")
		return
	}
	reason := "you are the weakest link, goodbye!"
	if len(cmd.Args) >= 2 {
		reason = strings.Join(cmd.Args[1:], " ")
	}
	_, err := cmd.Matrix.Client().KickUser(cmd.Room.MxRoom().ID, &mautrix.ReqKickUser{Reason: reason, UserID: id.UserID(cmd.Args[0])})
	if err != nil {
		debug.Print("Error in kick call:", err)
		debug.Print("Failed to kick user:", err)
	}
}

func cmdCreateRoom(cmd *Command) {
	req := &mautrix.ReqCreateRoom{}
	if len(cmd.Args) > 0 {
		req.Name = strings.Join(cmd.Args, " ")
	}
	room, err := cmd.Matrix.CreateRoom(req)
	if err != nil {
		cmd.Reply("Failed to create room:", err)
		return
	}
	cmd.MainView.SwitchRoom("", room)
}

func cmdPrivateMessage(cmd *Command) {
	if len(cmd.Args) == 0 {
		cmd.Reply("Usage: /pm <user id> [more user ids...]")
	}
	invites := make([]id.UserID, len(cmd.Args))
	for i, userID := range cmd.Args {
		invites[i] = id.UserID(userID)
		_, _, err := invites[i].Parse()
		if err != nil {
			cmd.Reply("%s isn't a valid user ID", userID)
			return
		}
	}
	req := &mautrix.ReqCreateRoom{
		Preset: "trusted_private_chat",
		Invite: invites,
	}
	room, err := cmd.Matrix.CreateRoom(req)
	if err != nil {
		cmd.Reply("Failed to create room:", err)
		return
	}
	cmd.MainView.SwitchRoom("", room)
}

func cmdJoin(cmd *Command) {
	if len(cmd.Args) == 0 {
		cmd.Reply("Usage: /join <room>")
		return
	}
	identifer := id.RoomID(cmd.Args[0])
	server := ""
	if len(cmd.Args) > 1 {
		server = cmd.Args[1]
	}
	room, err := cmd.Matrix.JoinRoom(identifer, server)
	debug.Print("Join room error:", err)
	if err == nil {
		cmd.MainView.AddRoom(room)
	}
}

func cmdMSendEvent(cmd *Command) {
	if len(cmd.Args) < 2 {
		cmd.Reply("Usage: /msend <event type> <content>")
		return
	}
	cmd.Args = append([]string{string(cmd.Room.MxRoom().ID)}, cmd.Args...)
	cmdSendEvent(cmd)
}

func cmdSendEvent(cmd *Command) {
	if len(cmd.Args) < 3 {
		cmd.Reply("Usage: /send <room id> <event type> <content>")
		return
	}
	roomID := id.RoomID(cmd.Args[0])
	eventType := event.NewEventType(cmd.Args[1])
	rawContent := strings.Join(cmd.Args[2:], " ")

	var content interface{}
	err := json.Unmarshal([]byte(rawContent), &content)
	debug.Print(err)
	if err != nil {
		cmd.Reply("Failed to parse content: %v", err)
		return
	}
	debug.Print("Sending event to", roomID, eventType, content)

	resp, err := cmd.Matrix.Client().SendMessageEvent(roomID, eventType, content)
	debug.Print(resp, err)
	if err != nil {
		cmd.Reply("Error from server: %v", err)
	} else {
		cmd.Reply("Event sent, ID: %s", resp.EventID)
	}
}

func cmdMSetState(cmd *Command) {
	if len(cmd.Args) < 2 {
		cmd.Reply("Usage: /msetstate <event type> <state key> <content>")
		return
	}
	cmd.Args = append([]string{string(cmd.Room.MxRoom().ID)}, cmd.Args...)
	cmdSetState(cmd)
}

func cmdSetState(cmd *Command) {
	if len(cmd.Args) < 4 {
		cmd.Reply("Usage: /setstate <room id> <event type> <state key/`-`> <content>")
		return
	}

	roomID := id.RoomID(cmd.Args[0])
	eventType := event.NewEventType(cmd.Args[1])
	stateKey := cmd.Args[2]
	if stateKey == "-" {
		stateKey = ""
	}
	rawContent := strings.Join(cmd.Args[3:], " ")

	var content interface{}
	err := json.Unmarshal([]byte(rawContent), &content)
	if err != nil {
		cmd.Reply("Failed to parse content: %v", err)
		return
	}
	debug.Print("Sending state event to", roomID, eventType, stateKey, content)
	resp, err := cmd.Matrix.Client().SendStateEvent(roomID, eventType, stateKey, content)
	if err != nil {
		cmd.Reply("Error from server: %v", err)
	} else {
		cmd.Reply("State event sent, ID: %s", resp.EventID)
	}
}

type ToggleMessage interface {
	Name() string
	Format(state bool) string
}

type HideMessage string

func (hm HideMessage) Format(state bool) string {
	if state {
		return string(hm) + " is now hidden"
	} else {
		return string(hm) + " is now visible"
	}
}

func (hm HideMessage) Name() string {
	return string(hm)
}

type SimpleToggleMessage string

func (stm SimpleToggleMessage) Format(state bool) string {
	if state {
		return "Disabled " + string(stm)
	} else {
		return "Enabled " + string(stm)
	}
}

func (stm SimpleToggleMessage) Name() string {
	return string(unicode.ToUpper(rune(stm[0]))) + string(stm[1:])
}

var toggleMsg = map[string]ToggleMessage{
	"rooms":         HideMessage("Room list sidebar"),
	"users":         HideMessage("User list sidebar"),
	"baremessages":  SimpleToggleMessage("bare message view"),
	"images":        SimpleToggleMessage("image rendering"),
	"typingnotif":   SimpleToggleMessage("typing notifications"),
	"emojis":        SimpleToggleMessage("emoji shortcode conversion"),
	"html":          SimpleToggleMessage("HTML input"),
	"markdown":      SimpleToggleMessage("markdown input"),
	"downloads":     SimpleToggleMessage("automatic downloads"),
	"notifications": SimpleToggleMessage("desktop notifications"),
}

func makeUsage() string {
	var buf strings.Builder
	buf.WriteString("Usage: /toggle <things...>\n\n")
	buf.WriteString("List of Things:\n")
	for key, value := range toggleMsg {
		_, _ = fmt.Fprintf(&buf, "* %s - %s\n", key, value.Name())
	}
	return buf.String()[:buf.Len()-1]
}

func cmdToggle(cmd *Command) {
	if len(cmd.Args) == 0 {
		cmd.Reply(makeUsage())
		return
	}
	for _, thing := range cmd.Args {
		var val *bool
		switch thing {
		case "rooms":
			val = &cmd.Config.Preferences.HideRoomList
		case "users":
			val = &cmd.Config.Preferences.HideUserList
		case "baremessages":
			val = &cmd.Config.Preferences.BareMessageView
		case "images":
			val = &cmd.Config.Preferences.DisableImages
		case "typingnotif":
			val = &cmd.Config.Preferences.DisableTypingNotifs
		case "emojis":
			val = &cmd.Config.Preferences.DisableEmojis
		case "html":
			val = &cmd.Config.Preferences.DisableHTML
		case "markdown":
			val = &cmd.Config.Preferences.DisableMarkdown
		case "downloads":
			val = &cmd.Config.Preferences.DisableDownloads
		case "notifications":
			val = &cmd.Config.Preferences.DisableNotifications
		default:
			cmd.Reply("Unknown toggle %s. Use /toggle without arguments for a list of togglable things.", thing)
			return
		}
		*val = !(*val)
		debug.Print(thing, *val)
		cmd.Reply(toggleMsg[thing].Format(*val))
	}
	cmd.UI.Render()
	go cmd.Matrix.SendPreferencesToMatrix()
}

func cmdLogout(cmd *Command) {
	cmd.Matrix.Logout()
}