// This file is part of beagles.
//
// Copyright © 2020 Chris Palmer <chris@red-oxide.org>
//
// 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"

	"github.com/gdamore/tcell"
	tui "gitlab.com/tslocum/cview"
)

type statusType int

const (
	listStatus statusType = iota
	contentStatus
	commandStatus
	helpStatus
)

type ui struct {
	InCmdMode   bool
	Status      statusType
	App         *app
	CommandLine *commandLine
	List        *list
	Content     *content
	StatusLine  *statusLine
	DB          *Storage
	Pages       *tui.Pages
}

func initUI(db *Storage, theme themeType) *ui {
	i := &ui{
		DB:          db,
		Content:     newContent(&theme),
		List:        newList(&theme),
		StatusLine:  newStatusLine(&theme),
		CommandLine: newCommandLine(&theme),
		App:         newApp(),
		Pages:       tui.NewPages(),
	}

	i.App.processInput(func(event *tcell.EventKey) *tcell.EventKey {
		switch event.Key() {
		case tcell.KeyEsc:
			if i.InCmdMode {
				i.App.draw(func() {
					i.CommandLine.clear()
				})
				i.setStatus(i.Status)
			}

			return event
		case tcell.KeyLeft:
			return i.moveLeft(event)
		case tcell.KeyDown:
			return i.moveDown(event)
		case tcell.KeyUp:
			return i.moveUp(event)
		case tcell.KeyRight:
			return i.moveRight(event)
		case tcell.KeyRune:
			switch event.Rune() {
			case ':':
				if i.InCmdMode {
					return event
				}

				i.setStatus(commandStatus)
				return nil
			case 'h':
				return i.moveLeft(event)
			case 'j':
				return i.moveDown(event)
			case 'k':
				return i.moveUp(event)
			case 'l':
				return i.moveRight(event)
			case 'm':
				return i.markRead(event)
			case 'n':
				return i.openLink(event)
			}
		}

		return event
	})

	i.CommandLine.onChange(func(text string) {
		if text == "" {
			i.setStatus(listStatus)
		}
	})

	i.CommandLine.onEnter(func(key tcell.Key) {
		input := i.CommandLine.getText()

		args := strings.Split(input, " ")

		switch args[0] {
		case ":quit", ":q":
			i.App.exit()
		case ":help", ":h", ":?":
			i.setStatus(helpStatus)
		case ":list":
			i.setStatus(listStatus)
		case ":add":
			i.addFeed(args)
		case ":remove", ":rm":
			i.deleteFeed(args)
		case ":update", ":up":
			i.updateFeed(args)
		}
		i.InCmdMode = false
	})
	i.createHelpPage(&theme)
	i.createListPage(&theme)
	i.setStatus(listStatus)
	return i
}

func (i *ui) updateFeed(args []string) {
	i.App.draw(func() {
		if err := i.DB.Update(); err != nil {
			i.CommandLine.setError(err.Error())
			i.setStatus(listStatus)
			return
		}
		i.Content.clear()
		i.List.clear()
		for x, item := range i.DB.Queue {
			if x == 0 {
				i.Content.setText(item.Item.Link, item.Item.Content)
			}
			i.List.add(item.Item)
		}
		i.CommandLine.clear()
	})
}

func (i *ui) addFeed(args []string) {
	i.App.draw(func() {
		if err := i.DB.CreateFeed(args[1]); err != nil {
			i.CommandLine.setError(err.Error())
			i.setStatus(listStatus)
			return
		}
		i.Content.clear()
		i.List.clear()
		for x, item := range i.DB.Queue {
			if x == 0 {
				i.Content.setText(item.Item.Link, item.Item.Content)
			}
			i.List.add(item.Item)
		}
		i.CommandLine.clear()
	})
}
func (i *ui) deleteFeed(args []string) {
	i.App.draw(func() {
		if err := i.DB.DeleteFeed(args[1]); err != nil {
			i.CommandLine.setError(err.Error())
			i.setStatus(listStatus)
			return
		}
		i.Content.clear()
		i.List.clear()
		for x, item := range i.DB.Queue {
			if x == 0 {
				i.Content.setText(item.Item.Link, item.Item.Content)
			}
			i.List.add(item.Item)
		}
		i.CommandLine.clear()
	})
}

func (i *ui) openLink(event *tcell.EventKey) *tcell.EventKey {
	switch i.Status {
	case listStatus, contentStatus:
		if i.InCmdMode {
			return event
		}

		if i.List.size() != 0 {
			index := i.List.index()
			item := i.DB.Queue[index].Item

			go openBrowser(item.Link)
		}
		return nil
	}

	return event
}

func (i *ui) markRead(event *tcell.EventKey) *tcell.EventKey {
	switch i.Status {
	case listStatus, contentStatus:
		if i.InCmdMode || i.List.size() == 0 {
			return event
		}

		i.App.draw(func() {
			index := i.List.remove()
			if err := i.DB.MarkRead(i.DB.Queue[index]); err != nil {
				i.CommandLine.setError(err.Error())
				i.setStatus(listStatus)
				return
			}

			size := i.List.size()

			if size > 0 && index != -1 {
				switch index {
				case size:
					index--
					i.List.setIndex(index)
				case 0:
					i.List.setIndex(0)
				default:
					i.List.setIndex(index)
				}
				item := i.DB.Queue[index].Item
				i.Content.setText(item.Link, item.Content)
			}

			if size == 0 {
				i.Content.setText("", "")
			}
		})
		return nil
	}

	return event
}

func (i *ui) moveLeft(event *tcell.EventKey) *tcell.EventKey {
	switch i.Status {
	case contentStatus:
		if i.InCmdMode {
			return event
		}
		i.setStatus(listStatus)

		return nil
	}
	return event
}
func (i *ui) moveRight(event *tcell.EventKey) *tcell.EventKey {
	switch i.Status {
	case listStatus:
		if i.InCmdMode {
			return event
		}

		i.setStatus(contentStatus)

		return nil
	}
	return event
}
func (i *ui) moveUp(event *tcell.EventKey) *tcell.EventKey {
	switch i.Status {
	case listStatus:
		if i.InCmdMode {
			return event
		}

		index := i.List.decrement()
		if index != -1 {
			item := i.DB.Queue[index].Item
			i.Content.setText(item.Link, item.Content)
		}

		return nil
	}
	return event
}
func (i *ui) moveDown(event *tcell.EventKey) *tcell.EventKey {
	switch i.Status {
	case listStatus:
		if i.InCmdMode {
			return event
		}
		index := i.List.increment()
		if index != -1 {
			item := i.DB.Queue[index].Item
			i.Content.setText(item.Link, item.Content)
		}

		return nil
	}
	return event
}

func (i *ui) createListPage(theme *themeType) {
	qc := tui.NewFlex()
	qc.SetDirection(tui.FlexColumn)
	qc.AddItem(i.List.Widget, 0, 3, false)
	qc.AddItem(newSeparator(theme, true), 1, 0, false)
	qc.AddItem(i.Content.Widget, 0, 6, false)

	cv := tui.NewFlex()
	cv.SetDirection(tui.FlexRow)
	cv.AddItem(newTitleLine(theme), 1, 0, false)
	cv.AddItem(qc, 0, 1, false)
	cv.AddItem(i.StatusLine.Widget, 1, 1, false)
	cv.AddItem(i.CommandLine.Widget, 1, 0, false)

	view := tui.NewFlex()
	view.AddItem(cv, 0, 1, false)

	resize := true
	visable := true
	i.Pages.AddPage("list", view, resize, visable)
}

func (i *ui) createHelpPage(theme *themeType) {
	text := `beagles v%s is available under the terms of the GPL-3.0 license.
Copyright © 2020  Chris Palmer <chris@red-oxide.org>
https://git.sr.ht/~chrisppy/beagles

KEYS:
	h,🠔
		move to the left section (if applicable)
	
	j,🠗
		navigate down in the current section (if applicable)
	
	k,🠕
		navigate up in the current section (if applicable)
	
	l,🠖
		move the the right section (if applicable)
	
	m
		mark current post as read when in --LIST-- or --CONTENT--

	n
		open post url when in --LIST-- or --CONTENT--

	:
		enter command mode

COMMANDS:
	add [url]
		add a feed

	remove,rm [url]
		remove the feed

	update,up
		update all feeds

	help,h,?
		display help page

	list
		display list page
	
	quit,q
		exit the application

SEE ALSO:
	Additional information can be found in the manual pages:
		beagles(1)
		beagles-config(5)
`

	h := tui.NewTextView()
	h.SetText(fmt.Sprintf(text, Version))
	h.SetTextAlign(tui.AlignLeft)

	bgColor := theme.BackgroundColor
	fgColor := theme.ForegroundColor
	if theme.Help != nil {
		bgColor = theme.Help.BackgroundColor
		fgColor = theme.Help.ForegroundColor
	}

	if bgColor == "transparent" {
		h.SetBackgroundColor(tcell.ColorDefault)
	} else {
		h.SetBackgroundColor(tcell.GetColor(bgColor))
	}

	h.SetTextColor(tcell.GetColor(fgColor))

	cv := tui.NewFlex()
	cv.SetDirection(tui.FlexRow)
	cv.AddItem(newTitleLine(theme), 1, 0, false)
	cv.AddItem(h, 0, 1, false)
	cv.AddItem(i.StatusLine.Widget, 1, 1, false)
	cv.AddItem(i.CommandLine.Widget, 1, 0, false)

	view := tui.NewFlex()
	view.AddItem(cv, 0, 1, false)

	resize := true
	visable := true
	i.Pages.AddPage("help", view, resize, visable)
}

func (i *ui) setStatus(s statusType) {
	switch s {
	case commandStatus:
		i.InCmdMode = true
		i.CommandLine.setText(":")
		i.StatusLine.setText("-- COMMAND --")
		i.App.switchTo(i.CommandLine.Widget)
		return
	case contentStatus:
		i.InCmdMode = false
		i.StatusLine.setText("-- CONTENT --")
		i.App.switchTo(i.Content.Widget)
	case helpStatus:
		i.InCmdMode = false
		i.StatusLine.setText("-- HELP --")
		i.Pages.SwitchToPage("help")
	default:
		i.InCmdMode = false
		i.StatusLine.setText("-- LIST --")
		i.Pages.SwitchToPage("list")
	}
	i.Status = s
}