// Copyright 2022 wanderer <a_mirre at utb dot cz>
// SPDX-License-Identifier: GPL-3.0-or-later

package xkcdreader

import (
	"fmt"
	"log"
	"os"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/layout"
	"fyne.io/fyne/v2/storage"
	"fyne.io/fyne/v2/theme"
	"fyne.io/fyne/v2/widget"
	"git.dotya.ml/wanderer/go-xkcdreader/cmd"
	"git.dotya.ml/wanderer/go-xkcdreader/xkcdreader/xkcd"
)

const appGreeting = "welcome to go-xkcdreader"

var (
	a           fyne.App
	latestComic = xkcd.GetLatest()
)

// RunApp performs sets up and runs the main application.
func RunApp() {
	// initialize the fyne application
	newApp()

	goxkcdreader := getApp()
	w := goxkcdreader.NewWindow(cmd.GetAppName())

	// mark this window as the main window
	w.SetMaster()

	centered := container.New(
		layout.NewHBoxLayout(),
		layout.NewSpacer(),
		makeGreeting(),
		layout.NewSpacer(),
	)

	w.SetContent(container.New(
		layout.NewVBoxLayout(),
		makeToolbar(),
		centered,
		makeTabs(),
	))

	w.Resize(fyne.NewSize(400, 400))
	w.ShowAndRun()
}

func newApp() {
	a = app.New()

	log.Println("Created a new fyne application")
}

func getApp() fyne.App {
	return a
}

// makeGreeting creates a greeting label.
func makeGreeting() *widget.Label {
	w := widget.NewLabel(appGreeting)
	w.TextStyle.Monospace = true

	return w
}

func makeToolbar() *widget.Toolbar {
	toolbar := widget.NewToolbar(
		widget.NewToolbarSpacer(),
		widget.NewToolbarAction(theme.HelpIcon(), func() {
			log.Println("Display help")
		}),
		widget.NewToolbarAction(theme.SettingsIcon(), func() {
			log.Println("Display settings")
		}),
		widget.NewToolbarAction(theme.InfoIcon(), aboutWindow),
	)

	return toolbar
}

func makeTabs() *container.AppTabs {
	tabs := container.NewAppTabs(
		container.NewTabItem("browse", makeBrowseUI()),
		container.NewTabItem("what if?", widget.NewLabel("serious answers to absurd questions and absurd advice for common concerns from xkcd's Randall Munroe")),
		container.NewTabItemWithIcon("search", theme.SearchIcon(), makeSearchTab()),
	)

	return tabs
}

func makeBrowseUI() *fyne.Container {
	// container for the image and surrounding elements
	imgC := container.New(
		layout.NewHBoxLayout(),
		widget.NewButtonWithIcon("", theme.NavigateBackIcon(), func() {
			log.Println("Previous comic")
		}),
		layout.NewSpacer(),
		container.NewCenter(
			// TODO(me): dynamically replace placeholder text with image once
			// fetched...
			// widget.NewLabel("img placeholder"),
			getImg(latestComic.Img, false),
		),
		layout.NewSpacer(),
		widget.NewButtonWithIcon("", theme.NavigateNextIcon(), func() {
			log.Println("Next comic")
		}),
	)

	browseUI := container.New(
		layout.NewVBoxLayout(),
		layout.NewSpacer(),
		container.NewCenter(
			container.NewVBox(
				&widget.Label{
					Text: "published on " +
						fmt.Sprint(
							latestComic.Year, "-",
							latestComic.Month, "-",
							latestComic.Day,
						),
					TextStyle: fyne.TextStyle{Italic: true},
				},
				container.NewHBox(
					&widget.Label{
						Text:      latestComic.Title,
						TextStyle: fyne.TextStyle{Bold: true},
					},
					&widget.Label{
						Text:      "(#" + fmt.Sprint(latestComic.Num) + ")",
						TextStyle: fyne.TextStyle{Monospace: true},
					},
				),
			),
		),
		imgC,
		layout.NewSpacer(),
		container.NewCenter(
			// comic "alt text"
			&widget.Label{
				Text:      latestComic.Alt,
				TextStyle: fyne.TextStyle{Italic: true},
			},
		),
	)

	return browseUI
}

// getComicLatest fetches latest comic, updates latestComic if necessary.
func getComicLatest() {
	comic := xkcd.GetLatest()

	if comic == nil {
		// TODO(me): properly handle the situation (i.e. bail early)
		log.Println("error getting latest comic")
	}

	// update latesComic, if necessary
	if latestComic != comic {
		latestComic = comic
	}
}

// get img from filesystem, resize it and return as *canvas.Image.
func getImg(imgURI string, local bool) *canvas.Image {
	if local {
		_, err := os.Stat(imgURI)
		// properly handle error, perhaps panic?...don't panic, I know..
		if err != nil {
			log.Println("failed to read file " + imgURI)
			return canvas.NewImageFromFile("")
		}

		img := canvas.NewImageFromFile(imgURI)

		img.SetMinSize(
			fyne.Size{
				Height: 383,
				Width:  273,
			},
		)

		img.ScaleMode = canvas.ImageScaleSmooth
		img.FillMode = canvas.ImageFillContain

		return img
	}

	preImg, err := storage.ParseURI(imgURI)
	if err != nil {
		log.Printf("error parsing comic URI: %q", err.Error())
	}

	// get the actual image
	img := canvas.NewImageFromURI(preImg)

	if img.Resource == nil {
		log.Println("error fetching the image file of the latest comic")
	}

	// set basic img properties
	img.SetMinSize(
		fyne.Size{
			// subject to change, this is what I consider to be sane defaults
			// atm...
			Height: 650,
			Width:  750,
		},
	)

	img.ScaleMode = canvas.ImageScaleSmooth
	img.FillMode = canvas.ImageFillContain

	return img
}