package gui

import (
	"fmt"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/pysentry/pysentry/src/core"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/dialog"
	"fyne.io/fyne/v2/driver/desktop"
	"fyne.io/fyne/v2/layout"
	"fyne.io/fyne/v2/theme"
	"fyne.io/fyne/v2/widget"
)

const appID = "io.github.pysentry.desktop"
const allFolders = "All"
const noFolder = "No folder"

type job = core.Job
type event = core.RunRecord

func Run() {
	a := app.NewWithID(appID)
	a.SetIcon(loadAppIcon())

	w := a.NewWindow("PySentry")
	configureSystemTray(a, w)
	w.Resize(fyne.NewSize(1120, 720))
	w.SetContent(newMainView(w))
	w.ShowAndRun()
}

func loadAppIcon() fyne.Resource {
	candidates := []string{}
	if executable, err := os.Executable(); err == nil {
		candidates = append(candidates, filepath.Join(filepath.Dir(executable), "assets", "pysentry-icon.png"))
	}
	if workingDir, err := os.Getwd(); err == nil {
		candidates = append(candidates, filepath.Join(workingDir, "assets", "pysentry-icon.png"))
	}
	for _, path := range candidates {
		if resource, err := fyne.LoadResourceFromPath(path); err == nil {
			return resource
		}
	}
	return theme.ComputerIcon()
}

func configureSystemTray(a fyne.App, w fyne.Window) {
	desk, ok := a.(desktop.App)
	if !ok {
		return
	}

	menu := fyne.NewMenu("PySentry",
		fyne.NewMenuItem("Show", func() {
			w.Show()
			w.RequestFocus()
		}),
		fyne.NewMenuItemSeparator(),
		fyne.NewMenuItem("Quit", func() {
			a.Quit()
		}),
	)
	desk.SetSystemTrayMenu(menu)
	w.SetCloseIntercept(func() {
		w.Hide()
	})
}

func newMainView(w fyne.Window) fyne.CanvasObject {
	store, jobs, err := core.OpenStore()
	if err != nil {
		return container.NewPadded(widget.NewLabel("Failed to load PySentry configuration: " + err.Error()))
	}
	events := collectActivity(jobs)

	nextJobID := nextID(jobs)
	selected := 0
	selectedFolder := allFolders
	schedulerPaused := false
	filteredJobs := filteredJobIndexes(jobs, selectedFolder)
	title := widget.NewLabelWithStyle(jobs[selected].Name, fyne.TextAlignLeading, fyne.TextStyle{Bold: true})
	folder := widget.NewLabel(jobs[selected].Folder)
	schedule := widget.NewLabel(jobs[selected].Schedule)
	command := widget.NewLabel(jobs[selected].Command)
	lastRun := widget.NewLabel(jobs[selected].LastRun)
	nextRun := widget.NewLabel(jobs[selected].NextRun)
	state := widget.NewLabel(jobs[selected].LastState)
	schedulerState := widget.NewLabel("Scheduler running")
	commandOutput := widget.NewTextGrid()
	commandOutput.SetText(jobs[selected].Output)
	commandOutputScroll := container.NewScroll(commandOutput)
	commandOutputScroll.SetMinSize(fyne.NewSize(520, 160))
	history := newHistoryView(&events)
	jobLogs := widget.NewList(
		func() int {
			if selected < 0 || selected >= len(jobs) {
				return 0
			}
			return len(jobs[selected].Logs)
		},
		func() fyne.CanvasObject { return widget.NewLabel("log") },
		func(id widget.ListItemID, item fyne.CanvasObject) {
			item.(*widget.Label).SetText(eventText(jobs[selected].Logs[id]))
		},
	)

	updateDetails := func(index int) {
		if index < 0 || index >= len(jobs) {
			title.SetText("No job selected")
			folder.SetText("")
			schedule.SetText("")
			command.SetText("")
			lastRun.SetText("")
			nextRun.SetText("")
			state.SetText("")
			commandOutput.SetText("")
			return
		}
		selected = index
		current := jobs[selected]
		title.SetText(current.Name)
		folder.SetText(displayFolder(current.Folder))
		schedule.SetText(current.Schedule)
		command.SetText(current.Command)
		lastRun.SetText(current.LastRun)
		nextRun.SetText(current.NextRun)
		state.SetText(current.LastState)
		commandOutput.SetText(current.Output)
	}
	refresh := func() {
		filteredJobs = filteredJobIndexes(jobs, selectedFolder)
		updateDetails(selected)
		jobLogs.Refresh()
		history.Refresh()
	}
	var scheduler *core.Scheduler

	list := widget.NewList(
		func() int { return len(filteredJobs) },
		func() fyne.CanvasObject {
			name := widget.NewLabelWithStyle("Job name", fyne.TextAlignLeading, fyne.TextStyle{Bold: true})
			meta := widget.NewLabel("schedule")
			status := widget.NewLabel("status")
			return container.NewVBox(name, meta, status)
		},
		func(id widget.ListItemID, item fyne.CanvasObject) {
			row := item.(*fyne.Container)
			name := row.Objects[0].(*widget.Label)
			meta := row.Objects[1].(*widget.Label)
			status := row.Objects[2].(*widget.Label)

			current := jobs[filteredJobs[id]]
			name.SetText(current.Name)
			meta.SetText(displayFolder(current.Folder) + "    " + current.Schedule + "    " + current.Command)
			status.SetText(statusText(current))
		},
	)
	list.OnSelected = func(id widget.ListItemID) {
		if id < 0 || id >= len(filteredJobs) {
			updateDetails(-1)
			return
		}
		updateDetails(filteredJobs[id])
	}
	list.Select(selected)

	folderSelect := widget.NewSelect(folderOptions(jobs), func(value string) {
		if value == "" {
			return
		}
		selectedFolder = value
		filteredJobs = filteredJobIndexes(jobs, selectedFolder)
		list.Refresh()
		if len(filteredJobs) == 0 {
			selected = -1
			updateDetails(-1)
			return
		}
		selected = filteredJobs[0]
		list.Select(0)
		refresh()
	})
	folderSelect.SetSelected(selectedFolder)

	addButton := widget.NewButtonWithIcon("New job", theme.ContentAddIcon(), func() {
		showJobDialog(w, "New job", job{Schedule: "@every 1m", Command: "echo PySentry job ran", Enabled: true, LastRun: "Never", NextRun: "After save", LastState: "Ready"}, func(saved job) {
			saved.ID = nextJobID
			nextJobID++
			jobs = append(jobs, saved)
			selected = len(jobs) - 1
			created := newEvent(saved.ID, saved.Name, "Created", "Job was added")
			jobs[selected].Logs = append([]event{created}, jobs[selected].Logs...)
			events = append([]event{created}, events...)
			_ = store.SaveJobs(jobs)
			folderSelect.Options = folderOptions(jobs)
			folderSelect.Refresh()
			targetFolder := filterValue(saved.Folder)
			if selectedFolder != allFolders && selectedFolder != targetFolder {
				selectedFolder = targetFolder
				folderSelect.SetSelected(targetFolder)
			}
			filteredJobs = filteredJobIndexes(jobs, selectedFolder)
			list.Refresh()
			list.Select(displayIndex(filteredJobs, selected))
			refresh()
		})
	})
	editButton := widget.NewButtonWithIcon("Edit", theme.DocumentCreateIcon(), func() {
		if selected < 0 || selected >= len(jobs) {
			return
		}
		showJobDialog(w, "Edit job", jobs[selected], func(saved job) {
			saved.ID = jobs[selected].ID
			saved.Logs = jobs[selected].Logs
			saved.Output = jobs[selected].Output
			jobs[selected] = saved
			updated := newEvent(saved.ID, saved.Name, "Updated", "Job settings changed")
			jobs[selected].Logs = append([]event{updated}, jobs[selected].Logs...)
			events = append([]event{updated}, events...)
			if scheduler != nil {
				scheduler.RefreshSchedule(selected)
			}
			_ = store.SaveJobs(jobs)
			folderSelect.Options = folderOptions(jobs)
			folderSelect.Refresh()
			list.Refresh()
			refresh()
		})
	})
	runButton := widget.NewButtonWithIcon("Run now", theme.MediaPlayIcon(), func() {
		if selected < 0 || selected >= len(jobs) {
			return
		}
		if schedulerPaused {
			dialog.ShowInformation("Scheduler paused", "Global pause is active. Resume the scheduler before running jobs.", w)
			return
		}
		ran := scheduler.RunNow(selected)
		if ran.Time == "" {
			return
		}
		events = append([]event{ran}, events...)
		list.Refresh()
		refresh()
	})
	stopAllButton := widget.NewButtonWithIcon("Pause all", theme.MediaStopIcon(), nil)
	stopAllButton.OnTapped = func() {
		schedulerPaused = !schedulerPaused
		if schedulerPaused {
			schedulerState.SetText("Scheduler paused")
			stopAllButton.SetText("Resume all")
			stopAllButton.SetIcon(theme.MediaPlayIcon())
			for index := range jobs {
				if jobs[index].Enabled {
					jobs[index].NextRun = "Scheduler paused"
				}
			}
			if scheduler != nil {
				scheduler.SetPaused(true)
			}
			events = append([]event{newEvent(0, "Scheduler", "Paused", "All job execution paused")}, events...)
		} else {
			schedulerState.SetText("Scheduler running")
			stopAllButton.SetText("Pause all")
			stopAllButton.SetIcon(theme.MediaStopIcon())
			for index := range jobs {
				if jobs[index].Enabled && jobs[index].NextRun == "Scheduler paused" {
					jobs[index].NextRun = "Waiting for scheduler"
				}
			}
			if scheduler != nil {
				scheduler.SetPaused(false)
			}
			events = append([]event{newEvent(0, "Scheduler", "Resumed", "All job execution resumed")}, events...)
		}
		list.Refresh()
		refresh()
	}
	pauseButton := widget.NewButtonWithIcon("Pause", theme.MediaPauseIcon(), func() {
		if selected < 0 || selected >= len(jobs) {
			return
		}
		current := &jobs[selected]
		current.Enabled = !current.Enabled
		if current.Enabled {
			current.LastState = "Ready"
			current.NextRun = "Waiting for scheduler"
			resumed := newEvent(current.ID, current.Name, "Resumed", "Job was enabled")
			current.Logs = append([]event{resumed}, current.Logs...)
			events = append([]event{resumed}, events...)
			if scheduler != nil {
				scheduler.RefreshSchedule(selected)
			}
		} else {
			current.LastState = "Paused"
			current.NextRun = "Paused"
			paused := newEvent(current.ID, current.Name, "Paused", "Job was disabled")
			current.Logs = append([]event{paused}, current.Logs...)
			events = append([]event{paused}, events...)
			if scheduler != nil {
				scheduler.RefreshSchedule(selected)
			}
		}
		_ = store.SaveJobs(jobs)
		list.Refresh()
		refresh()
	})
	deleteButton := widget.NewButtonWithIcon("Delete", theme.DeleteIcon(), func() {
		if selected < 0 || selected >= len(jobs) {
			return
		}
		deleted := jobs[selected]
		dialog.ShowConfirm("Delete job", fmt.Sprintf("Delete %q?", deleted.Name), func(confirm bool) {
			if !confirm {
				return
			}
			jobs = append(jobs[:selected], jobs[selected+1:]...)
			folderSelect.Options = folderOptions(jobs)
			folderSelect.Refresh()
			filteredJobs = filteredJobIndexes(jobs, selectedFolder)
			if len(filteredJobs) == 0 && selectedFolder != allFolders {
				selectedFolder = allFolders
				folderSelect.SetSelected(allFolders)
				filteredJobs = filteredJobIndexes(jobs, selectedFolder)
			}
			if len(filteredJobs) == 0 {
				selected = -1
			} else {
				selected = filteredJobs[0]
			}
			events = append([]event{newEvent(deleted.ID, deleted.Name, "Deleted", "Job was removed")}, events...)
			_ = store.SaveJobs(jobs)
			list.Refresh()
			if selected >= 0 {
				list.Select(displayIndex(filteredJobs, selected))
			}
			refresh()
		}, w)
	})

	toolbar := container.NewHBox(addButton, editButton, runButton, pauseButton, deleteButton, layout.NewSpacer())
	globalControls := container.NewHBox(stopAllButton, schedulerState, layout.NewSpacer())
	sidebarHeader := container.NewVBox(globalControls, widget.NewSeparator(), widget.NewLabelWithStyle("Folder", fyne.TextAlignLeading, fyne.TextStyle{Bold: true}), folderSelect, toolbar)
	sidebar := container.NewBorder(sidebarHeader, nil, nil, nil, list)

	details := container.NewVBox(
		title,
		widget.NewSeparator(),
		detailRow("Folder", folder),
		detailRow("Schedule", schedule),
		detailRow("Command", command),
		detailRow("Last run", lastRun),
		detailRow("Next run", nextRun),
		detailRow("State", state),
		widget.NewSeparator(),
		widget.NewLabelWithStyle("Command output", fyne.TextAlignLeading, fyne.TextStyle{Bold: true}),
		commandOutputScroll,
		widget.NewSeparator(),
		widget.NewLabelWithStyle("Selected job activity", fyne.TextAlignLeading, fyne.TextStyle{Bold: true}),
		jobLogs,
	)

	scheduler = core.NewScheduler(store, &jobs, func(record core.RunRecord) {
		events = append([]event{record}, events...)
		refresh()
	})
	scheduler.Start()

	tabs := container.NewAppTabs(
		container.NewTabItemWithIcon("Jobs", theme.ListIcon(), container.NewHSplit(sidebar, container.NewPadded(details))),
		container.NewTabItemWithIcon("History", theme.HistoryIcon(), history),
		container.NewTabItemWithIcon("Settings", theme.SettingsIcon(), settingsView(w, store, &jobs)),
	)
	tabs.SetTabLocation(container.TabLocationTop)

	return tabs
}

func statusText(j job) string {
	if !j.Enabled {
		return "Paused"
	}
	return j.LastState
}

func newEvent(jobID int, jobName string, state string, detail string) event {
	return event{
		Time:    time.Now().Format("15:04:05"),
		JobID:   jobID,
		JobName: jobName,
		Trigger: "UI",
		State:   state,
		Detail:  detail,
	}
}

func eventText(e event) string {
	trigger := e.Trigger
	if trigger == "" {
		trigger = "Unknown"
	}
	if e.LogFile != "" {
		return fmt.Sprintf("%s  %s  %s  %s  %s  %s", e.Time, trigger, e.JobName, e.State, e.Detail, e.LogFile)
	}
	return fmt.Sprintf("%s  %s  %s  %s  %s", e.Time, trigger, e.JobName, e.State, e.Detail)
}

func collectActivity(jobs []job) []event {
	var events []event
	for _, current := range jobs {
		events = append(events, current.Logs...)
	}
	return events
}

func nextID(jobs []job) int {
	next := 1
	for _, current := range jobs {
		if current.ID >= next {
			next = current.ID + 1
		}
	}
	return next
}

func detailRow(label string, value fyne.CanvasObject) fyne.CanvasObject {
	caption := widget.NewLabelWithStyle(label, fyne.TextAlignLeading, fyne.TextStyle{Bold: true})
	caption.Wrapping = fyne.TextTruncate
	return container.NewGridWithColumns(2, caption, value)
}

func filteredJobIndexes(jobs []job, folder string) []int {
	indexes := make([]int, 0, len(jobs))
	for index, current := range jobs {
		if folder == allFolders || filterValue(current.Folder) == folder {
			indexes = append(indexes, index)
		}
	}
	return indexes
}

func folderOptions(jobs []job) []string {
	options := []string{allFolders, noFolder}
	seen := map[string]bool{allFolders: true, noFolder: true}
	for _, current := range jobs {
		folder := strings.TrimSpace(current.Folder)
		if folder == "" || seen[folder] {
			continue
		}
		seen[folder] = true
		options = append(options, folder)
	}
	return options
}

func filterValue(folder string) string {
	if strings.TrimSpace(folder) == "" {
		return noFolder
	}
	return strings.TrimSpace(folder)
}

func displayFolder(folder string) string {
	if strings.TrimSpace(folder) == "" {
		return "(" + noFolder + ")"
	}
	return strings.TrimSpace(folder)
}

func displayIndex(indexes []int, jobIndex int) int {
	for display, index := range indexes {
		if index == jobIndex {
			return display
		}
	}
	return 0
}

func showJobDialog(w fyne.Window, title string, current job, onSave func(job)) {
	name := widget.NewEntry()
	name.SetPlaceHolder("Nightly backup")
	name.SetText(current.Name)
	folder := widget.NewEntry()
	folder.SetPlaceHolder("Maintenance")
	folder.SetText(current.Folder)
	schedule := widget.NewEntry()
	schedule.SetPlaceHolder("@every 1m")
	schedule.SetText(current.Schedule)
	command := widget.NewEntry()
	command.SetPlaceHolder("echo PySentry job ran")
	command.SetText(current.Command)
	enabled := widget.NewCheck("Enabled", nil)
	enabled.SetChecked(current.Enabled)

	form := dialog.NewForm(
		title,
		"Save",
		"Cancel",
		[]*widget.FormItem{
			widget.NewFormItem("Name", name),
			widget.NewFormItem("Folder", folder),
			widget.NewFormItem("Schedule", schedule),
			widget.NewFormItem("Command", command),
			widget.NewFormItem("", enabled),
		},
		func(saved bool) {
			if !saved {
				return
			}
			if strings.TrimSpace(name.Text) == "" || strings.TrimSpace(schedule.Text) == "" || strings.TrimSpace(command.Text) == "" {
				dialog.ShowError(fmt.Errorf("name, schedule, and command are required"), w)
				return
			}
			current.Name = strings.TrimSpace(name.Text)
			current.Folder = strings.TrimSpace(folder.Text)
			current.Schedule = strings.TrimSpace(schedule.Text)
			current.Command = strings.TrimSpace(command.Text)
			current.Enabled = enabled.Checked
			if current.LastRun == "" {
				current.LastRun = "Never"
			}
			if current.Enabled {
				current.NextRun = "Waiting for scheduler"
				if current.LastState == "" || current.LastState == "Paused" {
					current.LastState = "Ready"
				}
			} else {
				current.NextRun = "Paused"
				current.LastState = "Paused"
			}
			onSave(current)
		},
		w,
	)
	form.Resize(fyne.NewSize(560, 280))
	form.Show()
}

func newHistoryView(events *[]event) *fyne.Container {
	list := widget.NewList(
		func() int { return len(*events) },
		func() fyne.CanvasObject { return widget.NewLabel("event") },
		func(id widget.ListItemID, item fyne.CanvasObject) {
			item.(*widget.Label).SetText(eventText((*events)[id]))
		},
	)
	return container.NewPadded(list)
}

func settingsView(w fyne.Window, store *core.Store, jobs *[]job) fyne.CanvasObject {
	runOnStartup := widget.NewCheck("Start PySentry when I sign in", nil)
	minimizeToTray := widget.NewCheck("Keep running in the system tray", nil)
	minimizeToTray.SetChecked(store.Config.KeepRunningInTray)
	notifications := widget.NewCheck("Show desktop notifications for failed jobs", nil)
	notifications.SetChecked(store.Config.NotifyOnFailure)
	jobsDir := widget.NewEntry()
	jobsDir.SetText(store.Config.JobsDir)
	jobsDirBrowse := widget.NewButtonWithIcon("Browse", theme.FolderOpenIcon(), func() {
		chooseFolder(w, jobsDir)
	})
	logsDir := widget.NewEntry()
	logsDir.SetText(store.Config.LogsDir)
	logsDirBrowse := widget.NewButtonWithIcon("Browse", theme.FolderOpenIcon(), func() {
		chooseFolder(w, logsDir)
	})
	maxLogFiles := widget.NewEntry()
	maxLogFiles.SetText(strconv.Itoa(store.Config.MaxLogFiles))
	maxLogAgeDays := widget.NewEntry()
	maxLogAgeDays.SetText(strconv.Itoa(store.Config.MaxLogAgeDays))
	settingsStatus := widget.NewLabel("")

	saveSettings := widget.NewButtonWithIcon("Save settings", theme.DocumentSaveIcon(), func() {
		files, err := strconv.Atoi(strings.TrimSpace(maxLogFiles.Text))
		if err != nil || files <= 0 {
			settingsStatus.SetText("Max log files must be a positive number")
			return
		}
		days, err := strconv.Atoi(strings.TrimSpace(maxLogAgeDays.Text))
		if err != nil || days <= 0 {
			settingsStatus.SetText("Max log age days must be a positive number")
			return
		}
		store.Config.LogsDir = strings.TrimSpace(logsDir.Text)
		if strings.TrimSpace(jobsDir.Text) == "" {
			settingsStatus.SetText("Jobs directory is required")
			return
		}
		if strings.TrimSpace(logsDir.Text) == "" {
			settingsStatus.SetText("Logs directory is required")
			return
		}
		store.Config.JobsDir = strings.TrimSpace(jobsDir.Text)
		store.Config.MaxLogFiles = files
		store.Config.MaxLogAgeDays = days
		store.Config.KeepRunningInTray = minimizeToTray.Checked
		store.Config.NotifyOnFailure = notifications.Checked
		if err := store.SaveConfig(); err != nil {
			settingsStatus.SetText("Save failed: " + err.Error())
			return
		}
		if err := store.SaveJobs(*jobs); err != nil {
			settingsStatus.SetText("Jobs save failed: " + err.Error())
			return
		}
		if err := core.CleanupLogs(store.Paths.LogsDir, store.Config.MaxLogFiles, store.Config.MaxLogAgeDays); err != nil {
			settingsStatus.SetText("Saved, cleanup failed: " + err.Error())
			return
		}
		settingsStatus.SetText("Saved")
	})

	return container.NewPadded(container.NewVBox(
		widget.NewLabelWithStyle("Application", fyne.TextAlignLeading, fyne.TextStyle{Bold: true}),
		runOnStartup,
		minimizeToTray,
		notifications,
		widget.NewSeparator(),
		widget.NewLabelWithStyle("Storage", fyne.TextAlignLeading, fyne.TextStyle{Bold: true}),
		detailRow("Config YAML", widget.NewLabel(store.Paths.ConfigPath)),
		detailRow("Jobs directory", container.NewBorder(nil, nil, nil, jobsDirBrowse, jobsDir)),
		detailRow("Logs directory", container.NewBorder(nil, nil, nil, logsDirBrowse, logsDir)),
		detailRow("Max log files", maxLogFiles),
		detailRow("Max log age days", maxLogAgeDays),
		saveSettings,
		settingsStatus,
		widget.NewSeparator(),
		widget.NewLabelWithStyle("Scheduler", fyne.TextAlignLeading, fyne.TextStyle{Bold: true}),
		widget.NewLabel("Current core supports @every schedules. Cron expressions come next."),
	))
}

func chooseFolder(w fyne.Window, target *widget.Entry) {
	folderDialog := dialog.NewFolderOpen(func(uri fyne.ListableURI, err error) {
		if err != nil || uri == nil {
			return
		}
		target.SetText(uri.Path())
	}, w)
	folderDialog.Resize(fyne.NewSize(900, 640))
	folderDialog.Show()
}