// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2018 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package main

import (
	"fmt"
	"strings"
	"time"
	"unicode"

	"github.com/gdamore/tcell"
	"github.com/mattn/go-runewidth"
	"maunium.net/go/gomatrix"
	"maunium.net/go/tview"
)

type MainView struct {
	*tview.Grid

	roomList         *tview.List
	roomView         *tview.Pages
	rooms            map[string]*RoomView
	input            *AdvancedInputField
	currentRoomIndex int
	roomIDs          []string

	matrix *MatrixContainer
	debug  DebugPrinter
	gmx    Gomuks
	config *Config
	parent *GomuksUI
}

func (view *MainView) addItem(p tview.Primitive, x, y, w, h int) {
	view.Grid.AddItem(p, x, y, w, h, 0, 0, false)
}

func (ui *GomuksUI) NewMainView() tview.Primitive {
	mainView := &MainView{
		Grid:     tview.NewGrid(),
		roomList: tview.NewList(),
		roomView: tview.NewPages(),
		rooms:    make(map[string]*RoomView),
		input:    NewAdvancedInputField(),

		matrix: ui.matrix,
		debug:  ui.debug,
		gmx:    ui.gmx,
		config: ui.config,
		parent: ui,
	}

	mainView.SetColumns(30, 1, 0).SetRows(0, 1)

	mainView.roomList.
		ShowSecondaryText(false).
		SetSelectedBackgroundColor(tcell.ColorDarkGreen).
		SetSelectedTextColor(tcell.ColorWhite).
		SetBorderPadding(0, 0, 1, 0)

	mainView.input.
		SetDoneFunc(mainView.InputDone).
		SetChangedFunc(mainView.InputChanged).
		SetTabCompleteFunc(mainView.InputTabComplete).
		SetFieldBackgroundColor(tcell.ColorDefault).
		SetPlaceholder("Send a message...").
		SetPlaceholderExtColor(tcell.ColorGray).
		SetInputCapture(mainView.InputCapture)

	mainView.addItem(mainView.roomList, 0, 0, 2, 1)
	mainView.addItem(NewBorder(), 0, 1, 2, 1)
	mainView.addItem(mainView.roomView, 0, 2, 1, 1)
	mainView.AddItem(mainView.input, 1, 2, 1, 1, 0, 0, true)

	ui.mainView = mainView

	return mainView
}

func (view *MainView) InputChanged(text string) {
	if len(text) == 0 {
		go view.matrix.SendTyping(view.CurrentRoomID(), false)
	} else if text[0] != '/' {
		go view.matrix.SendTyping(view.CurrentRoomID(), true)
	}
}

func findWordToTabComplete(text string) string {
	output := ""
	runes := []rune(text)
	for i := len(runes) - 1; i >= 0; i-- {
		if unicode.IsSpace(runes[i]) {
			break
		}
		output = string(runes[i]) + output
	}
	return output
}

func (view *MainView) GetRoom(id string) *RoomView {
	return view.rooms[id]
}

func (view *MainView) InputTabComplete(text string, cursorOffset int) string {
	roomView, _ := view.rooms[view.CurrentRoomID()]
	if roomView != nil {
		str := runewidth.Truncate(text, cursorOffset, "")
		word := findWordToTabComplete(str)
		userCompletions := roomView.AutocompleteUser(word)
		if len(userCompletions) == 1 {
			text = str[0:len(str)-len(word)] + userCompletions[0] + text[len(str):]
		} else if len(userCompletions) > 1 && len(userCompletions) < 6 {
			roomView.status.Clear()
			fmt.Fprintf(roomView.status, "Completions: %s", strings.Join(userCompletions, ", "))
		}
	}
	return text
}

func (view *MainView) InputDone(key tcell.Key) {
	if key == tcell.KeyEnter {
		room, text := view.CurrentRoomID(), view.input.GetText()
		if len(text) == 0 {
			return
		} else if text[0] == '/' {
			args := strings.SplitN(text, " ", 2)
			command := strings.ToLower(args[0])
			args = args[1:]
			go view.HandleCommand(room, command, args)
		} else {
			go view.matrix.SendMessage(room, text)
		}
		view.input.SetText("")
	}
}

func (view *MainView) HandleCommand(room, command string, args []string) {
	view.gmx.Recover()
	view.debug.Print("Handling command", command, args)
	switch command {
	case "/quit":
		view.gmx.Stop()
	case "/clearcache":
		view.config.Session.Rooms = make(map[string]*gomatrix.Room)
		view.config.Session.NextBatch = ""
		view.config.Session.FilterID = ""
		view.config.Session.Save()
		view.gmx.Stop()
	case "/part":
		fallthrough
	case "/leave":
		view.matrix.client.LeaveRoom(room)
	case "/join":
		if len(args) == 0 {
			view.AddMessage(room, "Usage: /join <room>")
			break
		}
		view.debug.Print(view.matrix.JoinRoom(args[0]))
	default:
		view.AddMessage(room, "Unknown command.")
	}
}

func (view *MainView) InputCapture(key *tcell.EventKey) *tcell.EventKey {
	k := key.Key()
	if key.Modifiers() == tcell.ModCtrl {
		if k == tcell.KeyDown {
			view.SwitchRoom(view.currentRoomIndex + 1)
			view.roomList.SetCurrentItem(view.currentRoomIndex)
		} else if k == tcell.KeyUp {
			view.SwitchRoom(view.currentRoomIndex - 1)
			view.roomList.SetCurrentItem(view.currentRoomIndex)
		} else {
			return key
		}
	} else if k == tcell.KeyPgUp || k == tcell.KeyPgDn {
		msgView := view.rooms[view.CurrentRoomID()].MessageView()
		if k == tcell.KeyPgUp {
			msgView.PageUp()
		} else {
			msgView.PageDown()
		}
	} else {
		return key
	}
	return nil
}

func (view *MainView) CurrentRoomID() string {
	if len(view.roomIDs) == 0 {
		return ""
	}
	return view.roomIDs[view.currentRoomIndex]
}

func (view *MainView) SwitchRoom(roomIndex int) {
	if roomIndex < 0 {
		roomIndex = len(view.roomIDs) - 1
	}
	view.currentRoomIndex = roomIndex % len(view.roomIDs)
	view.roomView.SwitchToPage(view.CurrentRoomID())
	view.roomList.SetCurrentItem(roomIndex)
	view.parent.Render()
}

func (view *MainView) addRoom(index int, room string) {
	roomStore := view.matrix.GetRoom(room)

	view.roomList.AddItem(roomStore.GetTitle(), "", 0, func() {
		view.SwitchRoom(index)
	})
	if !view.roomView.HasPage(room) {
		roomView := NewRoomView(view, roomStore)
		view.rooms[room] = roomView
		view.roomView.AddPage(room, roomView, true, false)
		roomView.UpdateUserList()
	}
}

func (view *MainView) HasRoom(room string) bool {
	for _, existingRoom := range view.roomIDs {
		if existingRoom == room {
			return true
		}
	}
	return false
}

func (view *MainView) AddRoom(room string) {
	if view.HasRoom(room) {
		return
	}
	view.roomIDs = append(view.roomIDs, room)
	view.addRoom(len(view.roomIDs)-1, room)
}

func (view *MainView) RemoveRoom(room string) {
	if !view.HasRoom(room) {
		return
	}
	view.roomList.RemoveItem(view.currentRoomIndex)
	if view.CurrentRoomID() == room {
		view.SwitchRoom(view.currentRoomIndex - 1)
	}
	view.roomView.RemovePage(room)
}

func (view *MainView) SetRoomList(rooms []string) {
	view.roomIDs = rooms
	view.roomList.Clear()
	view.roomView.Clear()
	for index, room := range rooms {
		view.addRoom(index, room)
	}
	view.SwitchRoom(0)
}

func (view *MainView) SetTyping(room string, users []string) {
	roomView, ok := view.rooms[room]
	if ok {
		roomView.SetTyping(users)
		view.parent.Render()
	}
}

func (view *MainView) AddMessage(room, message string) {
	roomView, ok := view.rooms[room]
	if ok {
		roomView.content.AddMessage("", "*", message, time.Now())
		view.parent.Render()
	}
}

func (view *MainView) Render() {
	view.parent.Render()
}