// SPDX-License-Identifier: GPL-3.0-or-later

package ui

import (
	"github.com/diamondburned/gotk4/pkg/gtk/v4"

	"krino/gui/internal/model"
	"krino/internal/xdg"
)

// settingsWindow is Settings: krino's defaults, which every directory
// inherits, and how this window behaves. The first are written to
// krino.conf with the care a rules file is written with - checked first,
// the previous text kept as krino.conf.bak - and the second to gui.json,
// which krino itself never reads (his request, 2026-09-16).
type settingsWindow struct {
	w    *Window
	win  *gtk.Window
	main *model.MainConf

	rows   []*settingRow
	check  *gtk.Label
	save   *gtk.Button
	toSave bool
}

// showSettings opens it, one at a time.
func (w *Window) showSettings() {
	main, err := model.OpenMain(w.engine)
	if err != nil {
		w.setStatus("settings: %v", err)
		return
	}
	s := &settingsWindow{w: w, main: main}
	s.win = gtk.NewWindow()
	s.win.SetTitle("krino settings")
	s.win.SetTransientFor(&w.win.Window)
	s.win.SetModal(true)
	s.win.SetDefaultSize(560, 640)

	box := gtk.NewBox(gtk.OrientationVertical, 8)
	box.SetMarginStart(12)
	box.SetMarginEnd(12)
	box.SetMarginTop(12)
	box.SetMarginBottom(12)

	box.Append(heading("Defaults for every directory - " + xdg.Abbrev(main.File)))
	note := gtk.NewLabel("An empty field is one krino.conf does not set, and krino's own default applies. A directory's file overrides these.")
	note.SetXAlign(0)
	note.SetWrap(true)
	note.AddCSSClass("dim-label")
	box.Append(note)
	for _, head := range append(append([]string{}, model.MainSettings...), "log") {
		args, _, err := main.Setting(head)
		if err != nil {
			w.setStatus("settings: %v", err)
			return
		}
		row := newSettingRow(head, args, s.armSave)
		s.rows = append(s.rows, row)
		box.Append(row.root)
	}
	s.check = gtk.NewLabel("")
	s.check.SetXAlign(0)
	s.check.SetWrap(true)
	box.Append(s.check)

	box.Append(heading("This window"))
	kept := gtk.NewLabel("These are kept as you change them; the button below writes krino.conf, and is only lit when something above has changed.")
	kept.SetXAlign(0)
	kept.SetWrap(true)
	kept.AddCSSClass("dim-label")
	box.Append(kept)
	prefs := w.prefs
	colours := gtk.NewCheckButtonWithLabel("colour the configuration in the Text tab")
	colours.SetActive(prefs.Colours)
	colours.SetTooltipText("paint comments, strings, form heads and actions in the Text sub-tab")
	preview := gtk.NewCheckButtonWithLabel("show the file behind the selected row")
	preview.SetActive(prefs.Preview)
	preview.SetTooltipText("show the selected file under its explanation: a picture, a PDF's first page, or the first lines of text")
	selectAll := gtk.NewDropDownFromStrings([]string{"every file checked", "nothing checked"})
	if !prefs.SelectAll {
		selectAll.SetSelected(1)
	}
	selectAll.SetTooltipText("what a freshly scanned plan starts as: every file that can be acted on checked, as the terminal review does, or nothing checked so you pick")

	layout := gtk.NewDropDownFromStrings([]string{
		"file list beside the explanation",
		"file list on top, preview beside the explanation",
	})
	if prefs.Layout == model.LayoutStacked {
		layout.SetSelected(1)
	}
	layout.SetTooltipText("how the Plan tab is arranged")
	previewHeight := gtk.NewSpinButtonWithRange(80, 2000, 20)
	previewHeight.SetValue(float64(prefs.PreviewHeight))
	previewHeight.SetTooltipText("how tall the preview under an explanation is, in pixels; dragging the divider above it does the same")
	showSize := gtk.NewCheckButtonWithLabel("size")
	showSize.SetActive(prefs.ShowSize)
	showAge := gtk.NewCheckButtonWithLabel("age")
	showAge.SetActive(prefs.ShowAge)
	showRule := gtk.NewCheckButtonWithLabel("rule")
	showRule.SetActive(prefs.ShowRule)
	columns := gtk.NewBox(gtk.OrientationHorizontal, 12)
	columns.Append(showSize)
	columns.Append(showAge)
	columns.Append(showRule)
	columns.SetTooltipText("which of the optional columns the plan shows; file, action and where it would go are always there")

	sortOrder := gtk.NewDropDownFromStrings(sortItems())
	for i, o := range model.SortOrders {
		if o == prefs.Sort {
			sortOrder.SetSelected(uint(i))
		}
	}
	sortOrder.SetTooltipText("the order a freshly scanned plan is listed in; the picker in the toolbar changes it for one window")

	box.Append(field("sort by", sortOrder))
	box.Append(field("layout", layout))
	box.Append(field("columns", columns))
	box.Append(field("preview height", previewHeight))
	box.Append(field("after a scan", selectAll))
	box.Append(colours)
	box.Append(preview)

	apply := func() {
		which := model.LayoutSide
		if layout.Selected() == 1 {
			which = model.LayoutStacked
		}
		order := model.SortDefault
		if i := int(sortOrder.Selected()); i >= 0 && i < len(model.SortOrders) {
			order = model.SortOrders[i]
		}
		p := model.Prefs{
			Sort:          order,
			ShowSize:      showSize.Active(),
			ShowAge:       showAge.Active(),
			ShowRule:      showRule.Active(),
			Colours:       colours.Active(),
			Preview:       preview.Active(),
			SelectAll:     selectAll.Selected() == 0,
			PreviewHeight: int(previewHeight.Value()),
			Layout:        which,
		}
		w.applyPrefs(p)
		if err := p.Save(); err != nil {
			w.setStatus("settings: %v", err)
		}
	}
	colours.ConnectToggled(apply)
	preview.ConnectToggled(apply)
	selectAll.Connect("notify::selected", func() { apply() })
	layout.Connect("notify::selected", func() { apply() })

	s.save = gtk.NewButtonWithLabel("Save krino.conf")
	s.save.AddCSSClass("suggested-action")
	s.save.SetSensitive(false)
	s.save.SetTooltipText("nothing to save: the defaults above are as krino.conf has them. The window settings below need no saving - they are kept as you change them.")
	s.save.ConnectClicked(s.onSave)
	closeBtn := gtk.NewButtonWithLabel("Close")
	closeBtn.ConnectClicked(func() { s.win.Close() })
	// The buttons sit outside the scrolled area: on a short screen they
	// would otherwise be below the fold, which is where he found them.
	buttons := gtk.NewBox(gtk.OrientationHorizontal, 6)
	buttons.SetHAlign(gtk.AlignEnd)
	buttons.SetMarginStart(12)
	buttons.SetMarginEnd(12)
	buttons.SetMarginTop(8)
	buttons.SetMarginBottom(12)
	buttons.Append(closeBtn)
	buttons.Append(s.save)

	scroll := gtk.NewScrolledWindow()
	scroll.SetChild(box)
	scroll.SetVExpand(true)
	outer := gtk.NewBox(gtk.OrientationVertical, 0)
	outer.Append(scroll)
	outer.Append(gtk.NewSeparator(gtk.OrientationHorizontal))
	outer.Append(buttons)
	s.win.SetChild(outer)
	s.win.Show()
}

// armSave writes what the fields hold into the text and checks it, without
// touching the file: Save is what writes.
func (s *settingsWindow) armSave() {
	for _, row := range s.rows {
		value := row.value()
		was, _, err := s.main.Setting(row.head)
		if err != nil {
			s.check.SetText(escape(err.Error()))
			return
		}
		if value == was {
			continue
		}
		if err := s.main.SetSetting(row.head, value); err != nil {
			s.check.SetText(escape(err.Error()))
			row.set(was)
			continue
		}
		s.toSave = true
	}
	diags := s.main.Check()
	switch {
	case len(diags) == 0:
		s.check.SetText("")
		canSave := s.toSave && s.main.Modified()
		s.save.SetSensitive(canSave)
		if canSave {
			s.save.SetTooltipText("write krino.conf, keeping the previous text as krino.conf.bak")
		}
	default:
		s.check.SetText(escape(diags[0].Error()))
		s.check.AddCSSClass("error")
		s.save.SetSensitive(false)
	}
}

// onSave writes krino.conf and makes the new defaults the ones every tab
// works from.
func (s *settingsWindow) onSave() {
	if err := s.main.Save(); err != nil {
		s.check.SetText(escape(err.Error()))
		return
	}
	s.check.RemoveCSSClass("error")
	s.check.SetText("saved; the previous text is beside it as krino.conf.bak")
	s.save.SetSensitive(false)
	if err := s.w.reloadEngine(); err != nil {
		s.w.setStatus("saved, but the new configuration does not load: %v", err)
		return
	}
	s.w.setStatus("saved %s", escape(xdg.Abbrev(s.main.File)))
}

// settingHintsMain is the example shown in an empty krino.conf field, for
// the settings the directory form does not already describe.
var settingHintsMain = map[string]string{
	"log": `"~/.local/state/krino/krino.log"`,
}

// mainHint is the example for a krino.conf setting.
func mainHint(head string) string {
	if h, ok := settingHintsMain[head]; ok {
		return h
	}
	return settingHints[head]
}