//go:build gtk

package gui

import (
	"fmt"
	"strings"
	"time"
	"unicode/utf8"

	"github.com/diamondburned/gotk4/pkg/gdk/v4"
	"github.com/diamondburned/gotk4/pkg/gtk/v4"
	"tea.chunkbyte.com/kato/captioneer/src/diagnostics"
	"tea.chunkbyte.com/kato/captioneer/src/output/history"
)

func (a *Application) buildCaptionsPage() *gtk.Box {
	page := gtk.NewBox(gtk.OrientationVertical, 7)
	page.AddCSSClass("captioneer-content")

	toolbar := gtk.NewBox(gtk.OrientationHorizontal, 5)
	toolbar.AddCSSClass("toolbar")
	toolbar.Append(labelWithClass("CAPTION HISTORY", "section-title"))
	spacer := gtk.NewBox(gtk.OrientationHorizontal, 0)
	spacer.SetHExpand(true)
	toolbar.Append(spacer)
	toolbar.Append(toolButton("Copy Selected", "Copy the selected caption text", func() {
		copyBufferSelection(a.captionBuffer)
	}))
	toolbar.Append(toolButton("Copy Transcript", "Copy all final captions", func() {
		gdk.DisplayGetDefault().Clipboard().SetText(a.history.Transcript())
	}))
	toolbar.Append(toolButton("Clear", "Clear visible caption history", a.history.Clear))
	toolbar.Append(toolButton("Jump to Latest", "Resume at the newest caption", func() {
		scrollTextViewToEnd(a.captionView, a.captionScroll)
	}))
	page.Append(toolbar)

	a.captionBuffer = gtk.NewTextBuffer(nil)
	a.captionMetaTag = bufferTag(a.captionBuffer, "meta", "#8A9384")
	a.captionHintTag = bufferTag(a.captionBuffer, "hint", "#6E7763")
	a.captionView = gtk.NewTextViewWithBuffer(a.captionBuffer)
	a.captionView.SetEditable(false)
	a.captionView.SetCursorVisible(true)
	a.captionView.SetWrapMode(gtk.WrapWordChar)
	a.captionView.SetTopMargin(9)
	a.captionView.SetBottomMargin(9)
	a.captionView.SetLeftMargin(10)
	a.captionView.SetRightMargin(10)
	a.captionView.AddCSSClass("caption-view")
	a.captionScroll = gtk.NewScrolledWindow()
	a.captionScroll.SetPolicy(gtk.PolicyAutomatic, gtk.PolicyAutomatic)
	a.captionScroll.SetHExpand(true)
	a.captionScroll.SetVExpand(true)
	a.captionScroll.SetChild(a.captionView)
	a.captionScroll.AddCSSClass("inset-panel")
	page.Append(a.captionScroll)

	provisional := gtk.NewBox(gtk.OrientationHorizontal, 8)
	provisional.AddCSSClass("provisional-row")
	caption := labelWithClass("LIVE", "live-tag")
	caption.SetVAlign(gtk.AlignStart)
	caption.SetMarginTop(2)
	provisional.Append(caption)
	a.provisionalLabel = gtk.NewLabel("Waiting for speech…")
	a.provisionalLabel.SetXAlign(0)
	a.provisionalLabel.SetWrap(true)
	a.provisionalLabel.SetHExpand(true)
	provisional.Append(a.provisionalLabel)
	page.Append(provisional)

	return page
}

func (a *Application) buildConsolePage() *gtk.Box {
	page := gtk.NewBox(gtk.OrientationVertical, 7)
	page.AddCSSClass("captioneer-content")

	toolbar := gtk.NewBox(gtk.OrientationHorizontal, 5)
	toolbar.AddCSSClass("toolbar")
	toolbar.Append(labelWithClass("APPLICATION CONSOLE", "section-title"))
	spacer := gtk.NewBox(gtk.OrientationHorizontal, 0)
	spacer.SetHExpand(true)
	toolbar.Append(spacer)
	toolbar.Append(toolButton("Copy Selected", "Copy selected console output", func() {
		copyBufferSelection(a.consoleBuffer)
	}))
	toolbar.Append(toolButton("Copy All", "Copy all buffered console output", func() {
		copyBuffer(a.consoleBuffer)
	}))
	toolbar.Append(toolButton("Clear", "Clear the console display", func() {
		a.log.Clear()
		a.renderConsole()
	}))
	toolbar.Append(toolButton("Jump to Latest", "Resume at the newest message", func() {
		scrollTextViewToEnd(a.consoleView, a.consoleScroll)
	}))
	page.Append(toolbar)

	a.consoleBuffer = gtk.NewTextBuffer(nil)
	a.consoleMetaTag = bufferTag(a.consoleBuffer, "meta", "#79826F")
	a.consoleWarnTag = bufferTag(a.consoleBuffer, "warn", "#C79C4E")
	a.consoleErrorTag = bufferTag(a.consoleBuffer, "error", "#CF826D")
	a.consoleView = gtk.NewTextViewWithBuffer(a.consoleBuffer)
	a.consoleView.SetEditable(false)
	a.consoleView.SetCursorVisible(true)
	a.consoleView.SetWrapMode(gtk.WrapWordChar)
	a.consoleView.SetTopMargin(8)
	a.consoleView.SetBottomMargin(8)
	a.consoleView.SetLeftMargin(9)
	a.consoleView.SetRightMargin(9)
	a.consoleView.AddCSSClass("console-view")
	a.consoleScroll = gtk.NewScrolledWindow()
	a.consoleScroll.SetPolicy(gtk.PolicyAutomatic, gtk.PolicyAutomatic)
	a.consoleScroll.SetHExpand(true)
	a.consoleScroll.SetVExpand(true)
	a.consoleScroll.SetChild(a.consoleView)
	a.consoleScroll.AddCSSClass("inset-panel")
	page.Append(a.consoleScroll)

	return page
}

// tagSpan marks a character range of freshly rendered buffer text so a
// TextTag can be applied after SetText replaces the whole buffer.
type tagSpan struct {
	tag        *gtk.TextTag
	start, end int
}

func applyTagSpans(buffer *gtk.TextBuffer, spans []tagSpan) {
	for _, span := range spans {
		buffer.ApplyTag(span.tag, buffer.IterAtOffset(span.start), buffer.IterAtOffset(span.end))
	}
}

func (a *Application) renderHistory(snapshot history.Snapshot) {
	follow := isAtBottom(a.captionScroll)
	var text strings.Builder
	var spans []tagSpan
	offset := 0
	if len(snapshot.Finals) == 0 {
		hint := "No captions yet. Press START to begin listening."
		text.WriteString(hint)
		spans = append(spans, tagSpan{a.captionHintTag, 0, utf8.RuneCountInString(hint)})
	}
	for _, entry := range snapshot.Finals {
		meta := fmt.Sprintf("%s  [%s–%s]  ",
			entry.CreatedAt.Format("15:04:05"),
			formatCaptionTime(entry.StartedAt),
			formatCaptionTime(entry.EndedAt),
		)
		text.WriteString(meta)
		spans = append(spans, tagSpan{a.captionMetaTag, offset, offset + utf8.RuneCountInString(meta)})
		offset += utf8.RuneCountInString(meta)
		line := entry.Text + "\n"
		text.WriteString(line)
		offset += utf8.RuneCountInString(line)
	}
	a.captionBuffer.SetText(text.String())
	applyTagSpans(a.captionBuffer, spans)
	if snapshot.Provisional == nil || strings.TrimSpace(snapshot.Provisional.Text) == "" {
		a.provisionalLabel.SetText("Waiting for speech…")
	} else {
		a.provisionalLabel.SetText(snapshot.Provisional.Text)
	}
	if follow {
		scrollTextViewToEnd(a.captionView, a.captionScroll)
	}
}

func (a *Application) renderConsole() {
	follow := isAtBottom(a.consoleScroll)
	var text strings.Builder
	var spans []tagSpan
	offset := 0
	for _, entry := range a.log.Entries() {
		var severityTag *gtk.TextTag
		switch entry.Severity {
		case diagnostics.Warning:
			severityTag = a.consoleWarnTag
		case diagnostics.Error:
			severityTag = a.consoleErrorTag
		}
		meta := fmt.Sprintf("%s  %-7s  %-14s  ",
			entry.At.Format("15:04:05.000"),
			strings.ToUpper(string(entry.Severity)),
			"["+entry.Category+"]",
		)
		text.WriteString(meta)
		spans = append(spans, tagSpan{a.consoleMetaTag, offset, offset + utf8.RuneCountInString(meta)})
		offset += utf8.RuneCountInString(meta)
		line := entry.Message + "\n"
		text.WriteString(line)
		if severityTag != nil {
			spans = append(spans, tagSpan{severityTag, offset, offset + utf8.RuneCountInString(entry.Message)})
		}
		offset += utf8.RuneCountInString(line)
	}
	a.consoleBuffer.SetText(text.String())
	applyTagSpans(a.consoleBuffer, spans)
	if follow {
		scrollTextViewToEnd(a.consoleView, a.consoleScroll)
	}
}

func formatCaptionTime(value time.Duration) string {
	seconds := value.Seconds()
	return fmt.Sprintf("%02d:%05.2f", int(seconds)/60, seconds-float64(int(seconds)/60*60))
}

func isAtBottom(scroll *gtk.ScrolledWindow) bool {
	if scroll == nil {
		return true
	}
	adjustment := scroll.VAdjustment()
	return adjustment.Value()+adjustment.PageSize() >= adjustment.Upper()-4
}

func scrollTextViewToEnd(view *gtk.TextView, scroll *gtk.ScrolledWindow) {
	if view == nil || scroll == nil {
		return
	}
	view.ScrollToIter(view.Buffer().EndIter(), 0, false, 0, 1)
	adjustment := scroll.VAdjustment()
	adjustment.SetValue(adjustment.Upper())
}

func copyBufferSelection(buffer *gtk.TextBuffer) {
	if buffer == nil {
		return
	}
	start, end, ok := buffer.SelectionBounds()
	if !ok {
		return
	}
	gdk.DisplayGetDefault().Clipboard().SetText(buffer.Text(start, end, true))
}

func copyBuffer(buffer *gtk.TextBuffer) {
	if buffer == nil {
		return
	}
	start, end := buffer.Bounds()
	gdk.DisplayGetDefault().Clipboard().SetText(buffer.Text(start, end, true))
}

func bufferTag(buffer *gtk.TextBuffer, name, foreground string) *gtk.TextTag {
	tag := gtk.NewTextTag(name)
	tag.SetObjectProperty("foreground", foreground)
	buffer.TagTable().Add(tag)
	return tag
}

func labelWithClass(text, class string) *gtk.Label {
	label := gtk.NewLabel(text)
	label.AddCSSClass(class)
	label.SetXAlign(0)
	return label
}

func toolButton(text, tooltip string, callback func()) *gtk.Button {
	button := gtk.NewButtonWithLabel(text)
	button.SetTooltipText(tooltip)
	button.ConnectClicked(callback)
	return button
}