// Copyright (C) 2026 Danilo M. <danix@danix.xyz>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License version 2 as
// published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

package notify

import (
	"os"
	"path/filepath"
	"testing"
)

func TestResolveIconPathAndURI(t *testing.T) {
	if got := ResolveIcon("/usr/share/icons/x/apps/48/firefox.png"); got != "/usr/share/icons/x/apps/48/firefox.png" {
		t.Fatalf("path passthrough: %q", got)
	}
	if got := ResolveIcon("file:///tmp/shot.png"); got != "/tmp/shot.png" {
		t.Fatalf("uri: %q", got)
	}
	if got := ResolveIcon(""); got != "" {
		t.Fatalf("empty: %q", got)
	}
}

func TestResolveIconThemeName(t *testing.T) {
	root := t.TempDir()
	// Theme "Plum" inherits "Base"; the icon is only in Base.
	theme := filepath.Join(root, "icons", "Plum")
	base := filepath.Join(root, "icons", "Base")
	plumIndex := filepath.Join(theme, "index.theme")
	baseApp := filepath.Join(base, "apps", "48")
	if err := os.MkdirAll(filepath.Join(theme, "apps", "scalable"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.MkdirAll(baseApp, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(plumIndex, []byte("[Icon Theme]\nInherits=Base\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(baseApp, "firefox.svg"), []byte("<svg/>"), 0o644); err != nil {
		t.Fatal(err)
	}

	t.Setenv("XDG_DATA_HOME", root)
	t.Setenv("XDG_DATA_DIRS", "")
	t.Setenv("HOME", filepath.Join(root, "home"))
	if err := os.MkdirAll(filepath.Join(root, "home", ".config", "qt6ct"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(root, "home", ".config", "qt6ct", "qt6ct.conf"), []byte("icon_theme=Plum\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	got := ResolveIcon("firefox")
	want := filepath.Join(root, "icons", "Base", "apps", "48", "firefox.svg")
	if got != want {
		t.Fatalf("resolved %q, want %q", got, want)
	}
	if got := ResolveIcon("no-such-icon-xyz"); got != "" {
		t.Fatalf("missing name must be empty, got %q", got)
	}
}

// iconEnv builds a throwaway XDG tree, points qt6ct at theme, and returns the
// root. HOME, XDG_DATA_HOME and XDG_DATA_DIRS are restored after the test.
func iconEnv(t *testing.T, theme string) string {
	t.Helper()
	root := t.TempDir()
	home := filepath.Join(root, "home")
	if err := os.MkdirAll(filepath.Join(home, ".config", "qt6ct"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(home, ".config", "qt6ct", "qt6ct.conf"), []byte("icon_theme="+theme+"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	t.Setenv("XDG_DATA_HOME", root)
	t.Setenv("XDG_DATA_DIRS", "")
	t.Setenv("HOME", home)
	return root
}

// putIcon creates a placeholder icon file, and its parents.
func putIcon(t *testing.T, path string) {
	t.Helper()
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(path, []byte("<svg/>"), 0o644); err != nil {
		t.Fatal(err)
	}
}

// writeIndex writes a theme's index.theme with a single Inherits value.
func writeIndex(t *testing.T, dir, inherits string) {
	t.Helper()
	if err := os.MkdirAll(dir, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "index.theme"), []byte("[Icon Theme]\nInherits="+inherits+"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
}

func TestResolveIconFreedesktopLayout(t *testing.T) {
	root := iconEnv(t, "Flat")
	putIcon(t, filepath.Join(root, "icons", "Flat", "scalable", "apps", "firefox.svg"))
	putIcon(t, filepath.Join(root, "icons", "Flat", "48x48", "apps", "firefox.png"))
	want := filepath.Join(root, "icons", "Flat", "scalable", "apps", "firefox.svg")
	if got := ResolveIcon("firefox"); got != want {
		t.Fatalf("freedesktop scalable: got %q want %q", got, want)
	}

	root = iconEnv(t, "Grid")
	putIcon(t, filepath.Join(root, "icons", "Grid", "48x48", "apps", "gimp.png"))
	want = filepath.Join(root, "icons", "Grid", "48x48", "apps", "gimp.png")
	if got := ResolveIcon("gimp"); got != want {
		t.Fatalf("freedesktop raster: got %q want %q", got, want)
	}
}

func TestResolveIconSizePreference(t *testing.T) {
	root := iconEnv(t, "Sized")
	base := filepath.Join(root, "icons", "Sized")
	putIcon(t, filepath.Join(base, "apps", "48", "app.png"))
	putIcon(t, filepath.Join(base, "apps", "32@2x", "app.png"))
	want := filepath.Join(base, "apps", "32@2x", "app.png")
	if got := ResolveIcon("app"); got != want {
		t.Fatalf("@2x beats plain 48 (64px vs 48px): got %q want %q", got, want)
	}

	root = iconEnv(t, "Tied")
	base = filepath.Join(root, "icons", "Tied")
	putIcon(t, filepath.Join(base, "32x32@2x", "apps", "app.png"))
	putIcon(t, filepath.Join(base, "64x64", "apps", "app.png"))
	want = filepath.Join(base, "32x32@2x", "apps", "app.png")
	if got := ResolveIcon("app"); got != want {
		t.Fatalf("equal 64px must break ties deterministically: got %q want %q", got, want)
	}
}

func TestResolveIconInheritsCycle(t *testing.T) {
	root := iconEnv(t, "LoopA")
	writeIndex(t, filepath.Join(root, "icons", "LoopA"), "LoopB")
	writeIndex(t, filepath.Join(root, "icons", "LoopB"), "LoopA")
	putIcon(t, filepath.Join(root, "icons", "hicolor", "48x48", "apps", "app.png"))
	want := filepath.Join(root, "icons", "hicolor", "48x48", "apps", "app.png")
	if got := ResolveIcon("app"); got != want {
		t.Fatalf("cycle must terminate and fall through to hicolor: got %q want %q", got, want)
	}
}