package main

import (
	"fmt"
	"strings"
	"time"

	todotxt "github.com/br0xen/go-todotxt"
	"github.com/br0xen/termbox-util"
	termbox "github.com/nsf/termbox-go"
)

// MainScreen holds all that's going on
type MainScreen struct {
	viewPort       *ViewPort
	message        string
	messageTimeout time.Duration
	messageTime    time.Time
	mode           int

	inputField *termboxUtil.InputField

	currentList   string
	currentFilter string
	activeList    todotxt.TaskList
	displayList   []todotxt.Task

	undoQueue     []string
	redoQueue     []string
	backspaceDoes int
}

const (
	MainBundleListKey   = "mainscreen.list"
	MainBundleFilterKey = "mainscreen.filter"

	MainBundleListTodo = "mainscreen.list.todo"
	MainBundleListDone = "mainscreen.list.done"

	MainModalIdFilter  = "mainscreen.filter"
	MainModalIdAddTask = "mainscreen.addtask"

	MainBackspaceNothing = iota
	MainBackspaceMain
	MainBackspaceFilter
)

func (screen *MainScreen) initialize(bundle Bundle) error {
	if err := screen.reloadList(bundle); err != nil {
		return err
	}
	width, height := termbox.Size()
	screen.inputField = termboxUtil.CreateInputField(0, (height - 3), width, 1, DefaultFg, DefaultBg)
	screen.inputField.SetID("")
	screen.inputField.SetBordered(false)

	return nil
}

func (screen *MainScreen) reloadList(bundle Bundle) error {
	screen.displayList = []todotxt.Task{}
	screen.currentList = bundle.getString(MainBundleListKey, MainBundleListTodo)
	switch screen.currentList {
	case MainBundleListTodo:
		screen.setActiveList(*app.TaskList)
		if screen.currentFilter = bundle.getString(MainBundleFilterKey, ""); screen.currentFilter != "" {
			filteredList := app.filterList(&screen.activeList, screen.currentFilter)
			for _, av := range screen.activeList {
				for _, fv := range *filteredList {
					if av.String() == fv.String() {
						screen.displayList = append(screen.displayList, av)
						break
					}
				}
			}
		} else {
			for _, av := range screen.activeList {
				screen.displayList = append(screen.displayList, av)
			}
		}
	case MainBundleListDone:
		if err := app.LoadDoneList(); err != nil {
			return err
		}
		screen.setActiveList(*app.DoneList)
		if screen.currentFilter = bundle.getString(MainBundleFilterKey, ""); screen.currentFilter != "" {
			filteredList := app.filterList(&screen.activeList, screen.currentFilter)
			for _, av := range screen.activeList {
				for _, fv := range *filteredList {
					if av.String() == fv.String() {
						screen.displayList = append(screen.displayList, av)
						break
					}
				}
			}
		} else {
			for _, av := range screen.activeList {
				screen.displayList = append(screen.displayList, av)
			}
		}
	}
	return nil
}

func (screen *MainScreen) handleKeyEvent(event termbox.Event) int {
	if screen.inputField.GetID() != "" {
		return screen.handleInputKeyEvent(event)
	}
	if event.Ch == '?' {
		// Go to About Screen
		return ScreenAbout
	} else if event.Key == termbox.KeyBackspace || event.Key == termbox.KeyBackspace2 {

		if screen.backspaceDoes == MainBackspaceNothing {
			if screen.currentList == MainBundleListDone {
				screen.reloadList(screen.buildBundle(MainBundleListTodo, screen.currentFilter))
			} else if screen.currentFilter != "" {
				screen.reloadList(screen.buildBundle(screen.currentList, ""))
			}
		} else if screen.backspaceDoes == MainBackspaceMain {
			screen.reloadList(screen.buildBundle(MainBundleListTodo, screen.currentFilter))
		} else if screen.backspaceDoes == MainBackspaceFilter {
			screen.reloadList(screen.buildBundle(screen.currentList, ""))
		}
		return ScreenMain

	} else if event.Key == termbox.KeySpace {
		return screen.toggleTaskComplete()

	} else if event.Ch == 'L' {
		return screen.toggleViewList()

	} else if event.Ch == 'a' {
		return screen.startAddNewTask()

	} else if event.Ch == 'e' || event.Ch == 'l' || event.Key == termbox.KeyEnter {
		return screen.startEditTaskScreen()

	} else if event.Ch == 'j' || event.Key == termbox.KeyArrowDown {
		screen.moveCursorDown()

	} else if event.Ch == 'k' || event.Key == termbox.KeyArrowUp {
		screen.moveCursorUp()

	} else if event.Ch == '/' {
		screen.startFilter()

	} else if event.Ch == 'D' {
		screen.archiveCurrentItem()

	} else if event.Ch == 'q' {
		return ScreenExit
	}
	return ScreenMain
}

func (screen *MainScreen) handleConfirmKeyEvent(event termbox.Event) int {
	return ScreenMain
}

func (screen *MainScreen) handleInputKeyEvent(event termbox.Event) int {
	id := screen.inputField.GetID()
	if id == "filter" {
		if event.Key == termbox.KeyEnter {
			// Apply the filter
			filter := screen.inputField.GetValue()
			screen.inputField.SetID("")
			screen.inputField.SetValue("")
			screen.backspaceDoes = MainBackspaceFilter
			screen.reloadList(screen.buildBundle(screen.currentList, filter))
			return ScreenMain
		}
	} else if id == "add task" {
		if event.Key == termbox.KeyEnter {
			// Create the new item
			err := app.addTask(screen.inputField.GetValue())
			if err != nil {
				screen.setMessage(err.Error())
			}
			screen.inputField.SetID("")
			screen.inputField.SetValue("")
			if err = app.WriteList(); err != nil {
				screen.setMessage(err.Error())
				return ScreenMain
			}
			screen.reloadList(screen.buildBundle(screen.currentList, screen.currentFilter))
			return ScreenMain
		}
	}
	if event.Key == termbox.KeyBackspace || event.Key == termbox.KeyBackspace2 {
		if screen.inputField.GetValue() == "" {
			screen.reloadList(screen.buildBundle(screen.currentList, screen.inputField.GetValue()))
			screen.inputField.SetID("")
			screen.inputField.SetValue("")
			return ScreenMain
		}
	}
	screen.inputField.HandleEvent(event)
	return ScreenMain
}

func (screen *MainScreen) setActiveList(list todotxt.TaskList) {
	screen.activeList = todotxt.NewTaskList()
	for _, v := range list {
		screen.activeList.AddTask(&v)
	}
}

func (screen *MainScreen) drawScreen() {
	if screen.message == "" {
		screen.setMessageWithTimeout("Press '?' for help", -1)
	}
	screen.drawHeader()
	topId := 0
	for _, v := range screen.displayList {
		if v.Id > topId {
			topId = v.Id
		}
	}
	padCnt := fmt.Sprintf("%d", topId)
	for k, v := range screen.displayList {
		pad := strings.Repeat(" ", len(padCnt)-len(fmt.Sprintf("%d", v.Id)))
		useFg, useBg := DefaultFg, DefaultBg
		if k == screen.viewPort.cursor {
			useFg, useBg = CursorFg, CursorBg
		}
		termboxUtil.DrawStringAtPoint(pad+app.getTaskString(v), 0, k+1, useFg, useBg)
	}
	screen.drawFooter()
}

func (screen *MainScreen) drawHeader() {
	width, _ := termbox.Size()
	headerString := screen.currentFilter
	if headerString == "" {
		if screen.currentList == MainBundleListTodo {
			headerString = "Todo List"
		} else if screen.currentList == MainBundleListDone {
			headerString = "Done List"
		}
	}
	spaces := strings.Repeat(" ", ((width-len(headerString))/2)+1)
	termboxUtil.DrawStringAtPoint(fmt.Sprintf("%s%s%s", spaces, headerString, spaces), 0, 0, TitleFg, TitleBg)
}

func (screen *MainScreen) drawFooter() {
	if screen.messageTimeout > 0 && time.Since(screen.messageTime) > screen.messageTimeout {
		screen.clearMessage()
	}
	_, height := termbox.Size()
	if screen.inputField.GetID() != "" {
		termboxUtil.DrawStringAtPoint(screen.inputField.GetID()+": ", 0, height-2, DefaultFg, DefaultBg)
		screen.inputField.Draw()
	}
	// And the 'message'
	termboxUtil.DrawStringAtPoint(screen.message, 0, height-1, DefaultFg, DefaultBg)
}

func (screen *MainScreen) archiveCurrentItem() int {
	if screen.currentList != MainBundleListTodo {
		screen.setMessage("Task is already archived")
		return ScreenMain
	}
	// Find the task under the cursor
	if len(screen.displayList) > screen.viewPort.cursor {
		t := screen.displayList[screen.viewPort.cursor]
		if err := app.archiveTask(t.Id); err != nil {
			screen.setMessage(err.Error())
			return ScreenMain
		}
		if err := app.WriteList(); err != nil {
			screen.setMessage(err.Error())
			return ScreenMain
		}
		// Reload the list
		b := screen.buildBundle(screen.currentList, screen.currentFilter)
		if err := screen.reloadList(b); err != nil {
			screen.setMessage(err.Error())
		}
	}
	return ScreenMain
}

func (screen *MainScreen) startEditTaskScreen() int {
	// Find the task under the cursor
	if len(screen.displayList) > screen.viewPort.cursor {
		t := screen.displayList[screen.viewPort.cursor]
		// Load the task screen with this task
		b := Bundle{}
		b.setValue(TaskBundleTaskIdKey, t.Id)
		if err := app.screens[ScreenTask].initialize(b); err != nil {
			screen.setMessage(err.Error())
		}
		return ScreenTask
	}
	return ScreenMain
}

func (screen *MainScreen) reloadCurrentView() {
	bundle := Bundle{}
	bundle.setValue(MainBundleListKey, screen.currentList)
	bundle.setValue(MainBundleFilterKey, screen.currentFilter)
	screen.initialize(bundle)
}

func (screen *MainScreen) toggleViewList() int {
	bundle := Bundle{}
	if screen.currentList == MainBundleListTodo {
		bundle.setValue(MainBundleListKey, MainBundleListDone)
		screen.backspaceDoes = MainBackspaceMain
	} else {
		bundle.setValue(MainBundleListKey, MainBundleListTodo)
	}
	bundle.setValue(MainBundleFilterKey, screen.currentFilter)
	screen.initialize(bundle)
	return ScreenMain
}

func (screen *MainScreen) startAddNewTask() int {
	screen.inputField.SetID("add task")
	screen.inputField.SetX(len(screen.inputField.GetID()) + 2)
	return ScreenMain
}

func (screen *MainScreen) toggleTaskComplete() int {
	// Find the task under the cursor
	if len(screen.displayList) > screen.viewPort.cursor {
		t := screen.displayList[screen.viewPort.cursor]
		err := app.toggleTaskComplete(t.Id)
		if err != nil {
			screen.setMessage(err.Error())
			return ScreenMain
		}
		if err = app.WriteList(); err != nil {
			screen.setMessage(err.Error())
		}
	}
	screen.reloadCurrentView()
	return ScreenMain
}

func (screen *MainScreen) moveCursorDown() bool {
	screen.viewPort.cursor++
	if screen.viewPort.cursor >= len(screen.displayList) {
		screen.viewPort.cursor = len(screen.displayList) - 1
		return false
	}
	return true
}

func (screen *MainScreen) moveCursorUp() bool {
	screen.viewPort.cursor--
	if screen.viewPort.cursor < 0 {
		screen.viewPort.cursor = 0
		return false
	}
	return true
}

func (screen *MainScreen) startFilter() {
	screen.inputField.SetID("filter")
	screen.inputField.SetX(len(screen.inputField.GetID()) + 2)
}

func (screen *MainScreen) setMessage(msg string) {
	screen.message = msg
	screen.messageTime = time.Now()
	screen.messageTimeout = time.Second * 2
}

/* setMessageWithTimeout lets you specify the timeout for the message
 * setting it to -1 means it won't timeout
 */
func (screen *MainScreen) setMessageWithTimeout(msg string, timeout time.Duration) {
	screen.message = msg
	screen.messageTime = time.Now()
	screen.messageTimeout = timeout
}

func (screen *MainScreen) clearMessage() {
	screen.message = ""
	screen.messageTimeout = -1
}

func (screen *MainScreen) buildBundle(list, filter string) Bundle {
	bundle := Bundle{}
	bundle.setValue(MainBundleListKey, list)
	bundle.setValue(MainBundleFilterKey, filter)
	return bundle
}