package main

import (
	"errors"
	"testing"
	"time"

	"git.piksar.eu/piotr/groundstation/internal/display"
)

type recordingCanvas struct {
	width, height   int
	lines           []string
	clears, flushes int
}

func (c *recordingCanvas) Size() (int, int) { return c.width, c.height }
func (c *recordingCanvas) Clear()           { c.clears++ }
func (c *recordingCanvas) Text(_, _ int, message string) {
	c.lines = append(c.lines, message)
}
func (c *recordingCanvas) Flush() { c.flushes++ }

func TestBuildTargetBuildsIndependentVitureLayers(t *testing.T) {
	layers, err := buildTarget("x11")
	if err != nil {
		t.Fatal(err)
	}
	if len(layers) != 2 {
		t.Fatalf("layers=%d want the fallback canvas and the OSD overlay", len(layers))
	}
	canvas, osd := layers[0], layers[1]
	if canvas.Name != "fallback-canvas" || osd.Name != "osd-overlay" {
		t.Fatalf("layer names %q/%q want fallback-canvas/osd-overlay", canvas.Name, osd.Name)
	}

	canvasOpener, ok := canvas.Opener.(display.X11Opener)
	if !ok {
		t.Fatalf("canvas opener %T must be the X11 target", canvas.Opener)
	}
	if canvasOpener.Role != display.RoleBelow {
		t.Fatalf("canvas layer role %v must stay below video", canvasOpener.Role)
	}
	osdOpener, ok := osd.Opener.(display.X11Opener)
	if !ok {
		t.Fatalf("OSD opener %T must be the X11 target", osd.Opener)
	}
	if osdOpener.Role != display.RoleAbove {
		t.Fatalf("OSD layer role %v must stay above video", osdOpener.Role)
	}

	// Both layers must share one presence signal so the video lifecycle
	// observed by either session drives both templates.
	if canvasOpener.Video == nil || osdOpener.Video == nil || canvasOpener.Video != osdOpener.Video {
		t.Fatal("layers must share one video presence signal")
	}

	// The canvas layer keeps the target-specific fallback template with the
	// exact fallback text.
	canvasSurface := &recordingCanvas{width: 800, height: 600}
	canvas.Template.Draw(canvasSurface)
	if len(canvasSurface.lines) != 1 || canvasSurface.lines[0] != "Brak połączenia WFB" {
		t.Fatalf("canvas lines=%q want the exact fallback text", canvasSurface.lines)
	}

	// The OSD layer is the OSD surface, never the fallback.
	osdSurface := &recordingCanvas{width: 800, height: 600}
	osd.Template.Draw(osdSurface)
	if len(osdSurface.lines) != 0 {
		t.Fatalf("OSD lines=%q want none: the overlay must not duplicate the fallback", osdSurface.lines)
	}

	// Video presence hides the fallback on the canvas layer only.
	canvasOpener.Video.SetActive(true)
	canvasSurface.lines = nil
	canvas.Template.Draw(canvasSurface)
	if len(canvasSurface.lines) != 0 {
		t.Fatalf("canvas lines=%q must disappear while video is present", canvasSurface.lines)
	}
	canvasOpener.Video.SetActive(false)
}

func TestBuildTargetRejectsUnknownTarget(t *testing.T) {
	if _, err := buildTarget("hdmi-mirror"); err == nil {
		t.Fatal("unknown target must fail")
	}
}

func TestFormatDiagnosticRendersStructuredFields(t *testing.T) {
	got := formatDiagnostic(display.Diagnostic{
		Target:     "x11",
		Layer:      "fallback-canvas",
		Event:      display.EventOpenFailed,
		Err:        errors.New("connect X11: refused"),
		RetryDelay: 500 * time.Millisecond,
	})
	want := `target=x11 layer=fallback-canvas event=open_failed error="connect X11: refused" retry_delay=500ms`
	if got != want {
		t.Fatalf("formatDiagnostic=%q want %q", got, want)
	}
}

func TestWireDiagnosticsTagsEveryLayerWithItsName(t *testing.T) {
	layers, err := buildTarget("x11")
	if err != nil {
		t.Fatal(err)
	}

	wireDiagnostics("x11", layers)

	for _, layer := range layers {
		if layer.Options.Target != "x11" {
			t.Fatalf("layer %q target=%q want x11", layer.Name, layer.Options.Target)
		}
		if layer.Options.Layer != layer.Name {
			t.Fatalf("layer %q diagnostic layer=%q", layer.Name, layer.Options.Layer)
		}
		if layer.Options.Diagnostic == nil {
			t.Fatalf("layer %q must carry the reconnect diagnostic hook", layer.Name)
		}
	}

	// The shared hook must be safe to call from any layer goroutine.
	layers[0].Options.Diagnostic(display.Diagnostic{Target: "x11", Layer: layers[0].Name})
}