package ui

import (
	"bytes"
	"fmt"
	"log"
	"math"
	"net"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"text/template"

	"github.com/gdamore/tcell"
	"github.com/guillermo/go.procmeminfo"
	"github.com/knadh/koanf"
	"github.com/knadh/koanf/parsers/toml"
	"github.com/knadh/koanf/providers/confmap"
	"github.com/rivo/tview"

	"git.kemonine.info/PiFrame/config"
	"git.kemonine.info/PiFrame/utils"
	"git.kemonine.info/PiFrame/wifi"
)

const (
	CMD_SYSTEMCTL         = "/usr/bin/systemctl"
	CMD_FINDMNT           = "/usr/bin/findmnt"
	SYNCTHING_FOLDER_SKIP = ".stfolder"
)

const (
	PAGE_MAIN_UI   = "PAGE_MAIN_UI"
	PAGE_SAVE_EXIT = "PAGE_SAVE_EXIT"
	PAGE_EXIT      = "PAGE_EXIT"
	PAGE_REBOOT    = "PAGE_REBOOT"
	PAGE_POWEROFF  = "PAGE_POWEROFF"
)

// Bullshit to remove an element from a slice
func remove(s []string, index int) []string {
	return append(s[:index], s[index+1:]...)
}

// Housekeeping
var app *tview.Application
var main *tview.Flex
var menu *tview.List

// Function to reset the main input area that's used all over the place
func resetMain() {
	main.Clear()
	app.SetFocus(menu)
}

func ConfigGui(pfconfig *koanf.Koanf) {
	// Memory info for status panel
	meminfo := &procmeminfo.MemInfo{}
	err := meminfo.Update()
	if err != nil {
		log.Fatalf("Error getting memory info : %s", err)
	}

	// Network interfaces for status panel
	ifaces, err := net.Interfaces()
	if err != nil {
		log.Fatalf("Error getting netork interfaces : %s", err)
		return
	}

	// Disk use
	findmntOut, err := exec.Command(CMD_FINDMNT, "-n", "-l",
		"-o", "TARGET,USE%",
		"-t", "ext4,exfat,vfat,btrfs,zfs,xfs").Output()
	if err != nil {
		log.Fatalf("Error getting disk use : %s", err)
	}
	filesystems := strings.Split(strings.Trim(string(findmntOut), "\n"), "\n")

	// GPU Temp
	gpuTemp := fmt.Sprintf("%.2f'C", utils.GetGPUTemp())

	// CPU Temp
	cpuTemp := fmt.Sprintf("%.2f'C", utils.GetCPUTemp())

	// Get list of all folders that can be used as albums
	var albums []string
	err = filepath.Walk(pfconfig.String(config.CONFIG_KEY_ALBUMS_ROOT), func(path string, fi os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if fi.IsDir() {
			if strings.Contains(path, SYNCTHING_FOLDER_SKIP) {
				return nil
			}
			albumName := strings.TrimPrefix(path, pfconfig.String(config.CONFIG_KEY_ALBUMS_ROOT))
			if albumName == "" {
				albumName = "Main Folder"
			}
			albums = append(albums, albumName)
		}
		return nil
	})
	if err != nil {
		log.Fatalf("Error getting list of albums : %s", err)
	}

	// Run config UI when slideshow stops
	app = tview.NewApplication()

	// Header
	headerTitle := tview.NewTextView().
		SetText("PiFrame").
		SetTextAlign(tview.AlignCenter).
		SetTextColor(tcell.ColorAqua)

	headerSubTitle := tview.NewTextView().
		SetText("Management Utility").
		SetTextAlign(tview.AlignCenter).
		SetTextColor(tcell.ColorSilver)
	header := tview.NewFlex().
		SetDirection(tview.FlexRow)
	header.AddItem(headerTitle, 0, 1, false).
		AddItem(headerSubTitle, 0, 1, false)

	// Footer fields (Left Column)
	saveExitButton := tview.NewButton("Save & Exit").
		SetBackgroundColorActivated(tcell.ColorGray)
	saveExitButton.SetLabelColor(tcell.ColorBlack).
		SetBorder(true).
		SetBorderColor(tcell.ColorBlack).
		SetBackgroundColor(tcell.ColorGreen).
		SetRect(0, 0, 22, 3)

	exitButton := tview.NewButton("Exit").
		SetBackgroundColorActivated(tcell.ColorGray)
	exitButton.SetLabelColor(tcell.ColorBlack).
		SetBorder(true).
		SetBorderColor(tcell.ColorBlack).
		SetBackgroundColor(tcell.ColorYellow).
		SetRect(0, 0, 22, 3)

	rebootButton := tview.NewButton("Reboot").
		SetBackgroundColorActivated(tcell.ColorGray)
	rebootButton.SetLabelColor(tcell.ColorBlack).
		SetBorder(true).
		SetBorderColor(tcell.ColorBlack).
		SetBackgroundColor(tcell.ColorFuchsia).
		SetRect(0, 0, 22, 3)

	powerOffButton := tview.NewButton("Power Off").
		SetBackgroundColorActivated(tcell.ColorGray)
	powerOffButton.SetLabelColor(tcell.ColorBlack).
		SetBorder(true).
		SetBorderColor(tcell.ColorBlack).
		SetBackgroundColor(tcell.ColorRed).
		SetRect(0, 0, 22, 3)

	// Footer
	footer := tview.NewFlex()
	footer.AddItem(saveExitButton, 0, 1, false).
		AddItem(exitButton, 0, 1, false).
		AddItem(rebootButton, 0, 1, false).
		AddItem(powerOffButton, 0, 1, false)
	// Setup menu
	menu = tview.NewList()
	menu.SetBorder(true).
		SetTitle("Menu").
		SetTitleColor(tcell.ColorAqua)
	menu.AddItem("Select Albums", "", '1', nil)
	menu.AddItem("Intervals", "", '2', nil)
	menu.AddItem("WiFi", "", '3', nil)
	menu.AddItem("HDMI On/Off", "", '5', nil)
	menu.AddItem("Advanced", "", '6', nil)

	// Setup base var for main column so the menu setup is easier to manage
	main = tview.NewFlex().
		SetDirection(tview.FlexRow)

	// Setup main panel (Center column)
	main.SetTitle("").
		SetBorder(true).
		SetTitleColor(tcell.ColorAqua)

	// Select Albums Form
	selectAlbumsForm := tview.NewForm()
	configSelectedAlbums := pfconfig.Strings(config.CONFIG_KEY_ALBUMS_SELECTED)
	albumCheckboxes := []*tview.Checkbox{}
	for _, album := range albums {
		albumSelected := false
		for _, configSelectedAlbum := range configSelectedAlbums {
			if configSelectedAlbum == "/" {
				configSelectedAlbum = "Main Folder"
			}
			if album == configSelectedAlbum {
				albumSelected = true
			}
		}
		albumCheckbox := tview.NewCheckbox()
		albumCheckbox.SetLabel(album)
		albumCheckbox.SetChecked(albumSelected)
		albumCheckboxes = append(albumCheckboxes, albumCheckbox)
		selectAlbumsForm.AddFormItem(albumCheckbox)
	}
	selectAlbumsForm.AddButton("Apply", resetMain)
	selectAlbumsForm.AddButton("Cancel", resetMain)

	// Slide Interval Form
	intervalsForm := tview.NewForm()
	configSlideInterval := pfconfig.String(config.CONFIG_KEY_SLIDESHOW_INTERVAL)
	configRestartInterval := pfconfig.String(config.CONFIG_KEY_SLIDESHOW_RESTART_INTERVAL)
	intervalsForm.AddInputField("Slide", configSlideInterval, 0, nil, func(value string) {
		configSlideInterval = value
	})
	intervalsForm.AddInputField("Restart/Reshuffle", configRestartInterval, 0, nil, func(value string) {
		configRestartInterval = value
	})
	intervalsForm.AddButton("Apply", resetMain)
	intervalsForm.AddButton("Cancel", resetMain)

	// WiFi Config Form
	wifiConfigForm := tview.NewForm()
	wifiConfigAccessPoint := ""
	wifiConfigPassword := ""
	wifiConfigForm.AddInputField("Access Point", "", 0, nil, func(value string) {
		wifiConfigAccessPoint = value
	})
	wifiConfigForm.AddPasswordField("Password", "", 0, '*', func(value string) {
		wifiConfigPassword = value
	})
	wifiConfigForm.AddButton("Apply", func() {
		// Cleanup old wifi configs and apply new one
		nmWifi := wifi.New(wifiConfigAccessPoint, wifiConfigPassword)
		nmWifi.ApplyConfig()
		resetMain()
	})
	wifiConfigForm.AddButton("Cancel", resetMain)

	// HDMI On/Off Form
	hdmiForm := tview.NewForm()
	configHDMIOff := pfconfig.String(config.CONFIG_KEY_HDMI_OFF)
	configHDMIOn := pfconfig.String(config.CONFIG_KEY_HDMI_ON)
	hdmiForm.AddInputField("HDMI Off Schedule", configHDMIOff, 0, nil, func(value string) {
		configHDMIOff = value
	})
	hdmiForm.AddInputField("HDMI On Schedule", configHDMIOn, 0, nil, func(value string) {
		configHDMIOn = value
	})
	hdmiForm.AddButton("Apply", resetMain)
	hdmiForm.AddButton("Cancel", resetMain)

	// Advanced config form
	advancedForm := tview.NewForm()
	advancedForm.AddButton("Go Back", resetMain)

	// Setup menu selection handler
	menu.SetSelectedFunc(func(index int, title string, desc string, shortcut rune) {
		if title == "Select Albums" {
			main.SetTitle("Select Albums")
			main.Clear()
			main.AddItem(selectAlbumsForm, 0, 1, true)
			app.SetFocus(selectAlbumsForm)
		}
		if title == "WiFi" {
			main.SetTitle("Configure WiFi")
			main.Clear()
			main.AddItem(wifiConfigForm, 0, 1, true)
			app.SetFocus(wifiConfigForm)
		}
		if title == "Intervals" {
			main.SetTitle("Configure Intervals")
			main.Clear()
			main.AddItem(intervalsForm, 0, 1, true)
			main.AddItem(tview.NewTextView().SetText("Intervals are a number + letter\n\nUse\ns for seconds\nm for minutes\nh for hours"), 0, 1, false)
			app.SetFocus(intervalsForm)
		}
		if title == "HDMI On/Off" {
			main.SetTitle("Configure HDMI On/Off")
			main.Clear()
			main.AddItem(hdmiForm, 0, 1, true)
			main.AddItem(tview.NewTextView().SetText("These values are date+time combos\n\nPlease see https://www.freedesktop.org/software/systemd/man/systemd.time.html for details\n\nONLY adjust the times (24h format) if unsure of what to change"), 0, 1, false)
			app.SetFocus(hdmiForm)
		}
		if title == "Advanced" {
			main.SetTitle("Advanced Configuration")
			main.Clear()
			main.AddItem(tview.NewTextView().SetText("For advanced configuration edit /etc/default/pf.toml via the command line. There are a few config values that are DANGEROUS to adjust and not exposed through this ui."), 0, 1, false)
			main.AddItem(advancedForm, 0, 1, false)
			app.SetFocus(advancedForm)
		}
	})

	// Side bar fields
	sideBarCPUTempTitle := tview.NewTextView().
		SetText("CPU Temperature").
		SetTextColor(tcell.ColorYellow)
	sideBarCPUTemp := tview.NewTextView().
		SetText(fmt.Sprintf("  %s", cpuTemp))
	sideBarGPUTempTitle := tview.NewTextView().
		SetText("GPU Temperature").
		SetTextColor(tcell.ColorYellow)
	sideBarGPUTemp := tview.NewTextView().
		SetText(fmt.Sprintf("  %s", gpuTemp))
	sideBarMemoryTitle := tview.NewTextView().
		SetText("Memory Use (Mb)").
		SetTextColor(tcell.ColorYellow)
	divisor := math.Pow(1024.0, 2.0)
	sideBarMemoryStats := tview.NewTextView().
		SetText(fmt.Sprintf("  %.1f / %.1f",
			float64(meminfo.Used())/divisor,
			float64(meminfo.Total())/divisor))
	sideBarSwapTitle := tview.NewTextView().
		SetText("Swap Use").
		SetTextColor(tcell.ColorYellow)
	sideBarSwapStats := tview.NewTextView().
		SetText(fmt.Sprintf("  %d%%", meminfo.Swap()))
	sideBarFilesystemTitle := tview.NewTextView().
		SetText("Disk Use").
		SetTextColor(tcell.ColorYellow)
	var sideBarFilesystems []*tview.TextView
	for _, i := range filesystems {
		filesystemAsTextView := tview.NewTextView().
			SetText(fmt.Sprintf("  %s", i))
		sideBarFilesystems = append(sideBarFilesystems, filesystemAsTextView)
	}
	sideBarIPAddressesTitle := tview.NewTextView().
		SetText("IP Addresses").
		SetTextColor(tcell.ColorYellow)
	var sideBarIPAddresses []*tview.TextView
	for _, i := range ifaces {
		addrs, err := i.Addrs()
		if err != nil {
			continue
		}
		for _, a := range addrs {
			ipAsTextView := tview.NewTextView().
				SetText(fmt.Sprintf("  %v : %s", i.Name, a.String()))
			sideBarIPAddresses = append(sideBarIPAddresses, ipAsTextView)
		}
	}

	// Setup side bar (Right column)
	sideBar := tview.NewFlex().
		SetDirection(tview.FlexRow)
	sideBar.SetTitle("System Info").
		SetBorder(true).
		SetTitleColor(tcell.ColorAqua)
	sideBar.AddItem(sideBarCPUTempTitle, 1, 1, false)
	sideBar.AddItem(sideBarCPUTemp, 1, 1, false)
	sideBar.AddItem(sideBarGPUTempTitle, 1, 1, false)
	sideBar.AddItem(sideBarGPUTemp, 1, 1, false)
	sideBar.AddItem(sideBarMemoryTitle, 1, 1, false)
	sideBar.AddItem(sideBarMemoryStats, 1, 1, false)
	sideBar.AddItem(sideBarSwapTitle, 1, 1, false)
	sideBar.AddItem(sideBarSwapStats, 1, 1, false)
	sideBar.AddItem(sideBarFilesystemTitle, 1, 1, false)
	for _, filesystemAsTextView := range sideBarFilesystems {
		sideBar.AddItem(filesystemAsTextView, 1, 1, false)
	}
	sideBar.AddItem(sideBarIPAddressesTitle, 1, 1, false)
	for _, ipAsTextView := range sideBarIPAddresses {
		sideBar.AddItem(ipAsTextView, 1, 1, false)
	}

	// Pages
	pages := tview.NewPages()

	// Main UI
	mainUI := tview.NewGrid().
		SetRows(2, 0, 4).
		SetColumns(25, 50, 50).
		SetBorders(true).
		AddItem(header, 0, 0, 1, 3, 0, 0, false).
		AddItem(footer, 2, 0, 1, 3, 0, 0, false)

	mainUI.AddItem(menu, 1, 0, 1, 1, 0, 100, true).
		AddItem(main, 1, 1, 1, 1, 0, 100, false).
		AddItem(sideBar, 1, 2, 1, 1, 0, 100, false)

	pages.AddPage(PAGE_MAIN_UI, mainUI, true, true)

	// Button modals
	saveExitModal := tview.NewModal().
		SetText("Are you sure you want to [red]SAVE [red]& [red]EXIT?").
		AddButtons([]string{"Yes", "Cancel"}).
		SetDoneFunc(func(buttonIndex int, buttonLabel string) {
			if buttonLabel == "Yes" {
				// Deal with selected albums
				for _, checkbox := range albumCheckboxes {
					checkboxLabel := checkbox.GetLabel()
					// Undo beautification of checkbox label
					if checkboxLabel == "Main Folder" {
						checkboxLabel = "/"
					}
					// Track whether or not we need to add OR remove from config
					selected := checkbox.IsChecked()
					inConfig := false
					configIndex := 0

					// Walk the existing config values and bail if/when we find the album
					for configIndex = range configSelectedAlbums {
						if checkboxLabel == configSelectedAlbums[configIndex] {
							inConfig = true
							break
						}
					}
					// We need to add to the config
					if selected && !inConfig {
						configSelectedAlbums = append(configSelectedAlbums, checkboxLabel)
					}
					// We need to remove from the config
					if !selected && inConfig {
						configSelectedAlbums = remove(configSelectedAlbums, configIndex)
					}
				}

				// Apply HDMI configuration (on/off)
				var hdmiForDisk bytes.Buffer
				valueForTemplate := utils.SystemdTimer{OnCalendar: configHDMIOn}
				screenOn, err := template.New("screenon.systemd.timer").Parse(utils.SCREEN_ON_DOT_TIMER)
				if err != nil {
					log.Fatalf("Error setting up screen on systemd timer : %s", err)
				}
				err = screenOn.Execute(&hdmiForDisk, valueForTemplate)
				if err != nil {
					log.Fatalf("Error setting up screen on systemd timer : %s", err)
				}
				utils.WriteFile(utils.SCREEN_ON_TIMER_PATH, utils.SCREEN_ON_TIMER_PATH+".tmp", hdmiForDisk.Bytes())

				valueForTemplate.OnCalendar = configHDMIOff
				hdmiForDisk.Truncate(0)
				screenOff, err := template.New("screenoff.systemd.timer").Parse(utils.SCREEN_OFF_DOT_TIMER)
				if err != nil {
					log.Fatalf("Error setting up screen off systemd timer : %s", err)
				}
				err = screenOff.Execute(&hdmiForDisk, valueForTemplate)
				if err != nil {
					log.Fatalf("Error setting up screen off systemd timer : %s", err)
				}
				utils.WriteFile(utils.SCREEN_OFF_TIMER_PATH, utils.SCREEN_OFF_TIMER_PATH+".tmp", hdmiForDisk.Bytes())

				// Reload systemd units after applying HDMI config
				utils.SystemdDaemonReload()

				// Apply configuration updates to main config manager prior to saving
				pfconfig.Load(confmap.Provider(map[string]interface{}{
					config.CONFIG_KEY_SLIDESHOW_INTERVAL:         configSlideInterval,
					config.CONFIG_KEY_SLIDESHOW_RESTART_INTERVAL: configRestartInterval,
					config.CONFIG_KEY_HDMI_ON:                    configHDMIOn,
					config.CONFIG_KEY_HDMI_OFF:                   configHDMIOff,
					config.CONFIG_KEY_ALBUMS_SELECTED:            configSelectedAlbums,
				}, "."), nil)

				// Save configuration
				parser := toml.Parser()
				configForDisk, err := pfconfig.Marshal(parser)
				if err != nil {
					log.Fatalf("Error preparing config for disk write : %s", err)
				}
				utils.WriteFile(config.CONFIG_FILE_PATH, config.CONFIG_FILE_PATH_TMP, configForDisk)
				app.Stop()
				os.Exit(0)
			}
			pages.SwitchToPage(PAGE_MAIN_UI)
		})
	pages.AddPage(PAGE_SAVE_EXIT, saveExitModal, true, false)
	saveExitButton.SetSelectedFunc(func() {
		pages.ShowPage(PAGE_SAVE_EXIT)
	})

	exitModal := tview.NewModal().
		SetText("Are you sure you want to [red]EXIT?").
		AddButtons([]string{"Yes", "Cancel"}).
		SetDoneFunc(func(buttonIndex int, buttonLabel string) {
			if buttonLabel == "Yes" {
				app.Stop()
			}
			pages.SwitchToPage(PAGE_MAIN_UI)
		})
	pages.AddPage(PAGE_EXIT, exitModal, true, false)
	exitButton.SetSelectedFunc(func() {
		pages.ShowPage(PAGE_EXIT)
	})

	rebootModal := tview.NewModal().
		SetText("Are you sure you want to [red]REBOOT?").
		AddButtons([]string{"Yes", "Cancel"}).
		SetDoneFunc(func(buttonIndex int, buttonLabel string) {
			if buttonLabel == "Yes" {
				err := exec.Command(CMD_SYSTEMCTL, "reboot").Run()
				if err != nil {
					log.Fatalf("Could not reboot : %s ", err)
				}
			}
			pages.SwitchToPage(PAGE_MAIN_UI)
		})
	pages.AddPage(PAGE_REBOOT, rebootModal, true, false)
	rebootButton.SetSelectedFunc(func() {
		pages.ShowPage(PAGE_REBOOT)
	})

	powerOffModal := tview.NewModal().
		SetText("Are you sure you want to [red]POWER [red]OFF?").
		AddButtons([]string{"Yes", "Cancel"}).
		SetDoneFunc(func(buttonIndex int, buttonLabel string) {
			if buttonLabel == "Yes" {
				err := exec.Command(CMD_SYSTEMCTL, "poweroff").Run()
				if err != nil {
					log.Fatalf("Could not power off : %s ", err)
				}
			}
			pages.SwitchToPage(PAGE_MAIN_UI)
		})
	pages.AddPage(PAGE_POWEROFF, powerOffModal, true, false)
	powerOffButton.SetSelectedFunc(func() {
		pages.ShowPage(PAGE_POWEROFF)
	})

	// Setup tracking of which are of the UI can/has focus
	primitivesThatCanFocus := []tview.Primitive{menu, saveExitButton, exitButton, rebootButton, powerOffButton}
	currentFocus := 0

	// Setup basic switching between main menu and buttons for the UI
	app.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		// Don't process input if we aren't on an existing element that can focus
		canContinue := false
		focusedPrimitive := app.GetFocus()

		// Override some of the default behavior so up/dn move between fields in forms
		//     Per API GetFocusedItemIndex on a form will be -1 if a form item isn't currently focused
		//     We use this as a bit of a cheat to figure out if we're inside of a form that needs better nav options for users (ie. tab doesn't exist on a remote)
		albumField, albumButton := selectAlbumsForm.GetFocusedItemIndex()
		intervalField, intervalButton := intervalsForm.GetFocusedItemIndex()
		wifiField, wifiButton := wifiConfigForm.GetFocusedItemIndex()
		hdmiField, hdmiButton := hdmiForm.GetFocusedItemIndex()
		advancedField, advancedButton := advancedForm.GetFocusedItemIndex()
		if wifiField != -1 || wifiButton != -1 ||
			albumField != -1 || albumButton != -1 ||
			intervalField != -1 || intervalButton != -1 ||
			hdmiField != -1 || hdmiButton != -1 ||
			advancedField != -1 || advancedButton != -1 {
			switch event.Key() {
			case tcell.KeyUp:
				return tcell.NewEventKey(tcell.KeyBacktab, 0, event.Modifiers())
			case tcell.KeyDown:
				return tcell.NewEventKey(tcell.KeyTab, 0, event.Modifiers())
			}
		}

		// Standard override for the screen primitives we are using (ie. don't take over control in modals)
		for _, primitive := range primitivesThatCanFocus {
			if primitive == focusedPrimitive {
				canContinue = true
				break
			}
		}

		// Bail if we shouldn't be affecting user input
		if !canContinue {
			return event
		}

		// Add various forms of nav that make sense for a TUI (common stuff folks are used to)
		currentFocusChanged := false
		switch event.Key() {
		case tcell.KeyRight, tcell.KeyTab:
			currentFocus += 1
			if currentFocus >= len(primitivesThatCanFocus) {
				currentFocus = 0
			}
			currentFocusChanged = true
		case tcell.KeyLeft, tcell.KeyBacktab:
			currentFocus -= 1
			if currentFocus < 0 {
				currentFocus = len(primitivesThatCanFocus) - 1
			}
			currentFocusChanged = true
		}

		// Update the focus based on navigation
		if currentFocusChanged {
			app.SetFocus(primitivesThatCanFocus[currentFocus])
			return nil
		}

		// Pass through event so the main UI can process stuff properly
		return event
	})

	// Show UI and panic if there are any errors
	if err := app.SetRoot(pages, true).SetFocus(primitivesThatCanFocus[currentFocus]).EnableMouse(false).Run(); err != nil {
		log.Fatalf("Failed to run UI : %s", err)
	}
}