package theming

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

	"github.com/MDietermann/ArduinoArchSetup/internal/config"
)

func TestListDiscoversThemes(t *testing.T) {
	themes := List()
	if len(themes) == 0 {
		t.Fatal("no themes discovered")
	}
	for _, th := range themes {
		if th.ID == "" || th.DisplayName == "" || th.NvChadTheme == "" {
			t.Errorf("incomplete theme: %+v", th)
		}
	}
}

func TestGetKnownThemeReturnsMatch(t *testing.T) {
	got, ok := Get("gruvbox")
	if !ok {
		t.Fatal("gruvbox should exist")
	}
	if got.ID != "gruvbox" || got.DisplayName == "" || got.NvChadTheme != "gruvbox" {
		t.Fatalf("got %+v", got)
	}
}

func TestGetUnknownThemeReturnsFalse(t *testing.T) {
	if _, ok := Get("does-not-exist"); ok {
		t.Fatal("bogus id should return ok=false")
	}
}

func TestListIsSortedByID(t *testing.T) {
	themes := List()
	for i := 1; i < len(themes); i++ {
		if themes[i].ID < themes[i-1].ID {
			t.Fatalf("not sorted: %s before %s", themes[i-1].ID, themes[i].ID)
		}
	}
}

func TestApplyWritesFourToolConfigs(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	if err := Apply(config.Config{}, "gruvbox"); err != nil {
		t.Fatal(err)
	}

	checks := []struct{ rel, wantPrefix string }{
		{".config/starship.toml", "palette"},
		{".config/zellij/config.kdl", "theme"},
		{".config/yazi/theme.toml", ""},
		{".config/lazygit/config.yml", "gui"},
	}
	for _, c := range checks {
		data, err := os.ReadFile(filepath.Join(home, c.rel))
		if err != nil {
			t.Errorf("%s missing: %v", c.rel, err)
			continue
		}
		if len(data) == 0 {
			t.Errorf("%s empty", c.rel)
		}
		if c.wantPrefix != "" && !strings.HasPrefix(strings.TrimSpace(string(data)), c.wantPrefix) {
			t.Errorf("%s: want prefix %q, got %q", c.rel, c.wantPrefix, string(data[:min(len(data), 40)]))
		}
	}
}

func TestApplyUnknownThemeErrors(t *testing.T) {
	if err := Apply(config.Config{}, "does-not-exist"); err == nil {
		t.Fatal("want error on unknown theme")
	}
}

func TestApplyUpdatesOverlayActive(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	if err := Apply(config.Config{}, "gruvbox"); err != nil {
		t.Fatal(err)
	}
	data, err := os.ReadFile(filepath.Join(home, ".config", "archduino", "overlay.yaml"))
	if err != nil {
		t.Fatalf("overlay missing: %v", err)
	}
	if !strings.Contains(string(data), "__active: gruvbox") {
		t.Fatalf("overlay missing active theme: %s", data)
	}
}

func TestApplyPreservesOtherOverlayKeys(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	op := filepath.Join(home, ".config", "archduino", "overlay.yaml")
	if err := os.MkdirAll(filepath.Dir(op), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(op, []byte("version: 1\nextra_packages:\n  - foo\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	if err := Apply(config.Config{}, "gruvbox"); err != nil {
		t.Fatal(err)
	}
	data, _ := os.ReadFile(op)
	if !strings.Contains(string(data), "- foo") {
		t.Fatalf("extra_packages lost: %s", data)
	}
	if !strings.Contains(string(data), "__active: gruvbox") {
		t.Fatalf("active theme missing after preserve: %s", data)
	}
}

func TestApplyRewritesChadrcIfPresent(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	nvimCfg := filepath.Join(home, ".config", "nvim", "lua")
	if err := os.MkdirAll(nvimCfg, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(nvimCfg, "chadrc.lua"),
		[]byte(`M.base46 = { theme = "onedark" }`), 0o644); err != nil {
		t.Fatal(err)
	}

	// The real ChadrcWriter lives in the neovim package, which cannot be
	// imported here without creating an import cycle (neovim→theming).
	// Stub it with a minimal writer that covers what the test asserts.
	prev := ChadrcWriter
	t.Cleanup(func() { ChadrcWriter = prev })
	ChadrcWriter = func(name string) error {
		return os.WriteFile(filepath.Join(nvimCfg, "chadrc.lua"),
			[]byte(`theme = "`+name+`"`), 0o644)
	}

	if err := Apply(config.Config{}, "gruvbox"); err != nil {
		t.Fatal(err)
	}
	data, _ := os.ReadFile(filepath.Join(nvimCfg, "chadrc.lua"))
	if !strings.Contains(string(data), `theme = "gruvbox"`) {
		t.Fatalf("chadrc not rewritten: %s", data)
	}
	if strings.Contains(string(data), `theme = "onedark"`) {
		t.Fatalf("old theme still present: %s", data)
	}
}

func TestApplyNoChadrcIsFine(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	if err := Apply(config.Config{}, "gruvbox"); err != nil {
		t.Fatal(err)
	}
}

func TestAllFiveThemesPresent(t *testing.T) {
	want := []string{"catppuccin", "dracula", "gruvbox", "nord", "tokyonight"}
	themes := List()
	if len(themes) != len(want) {
		t.Fatalf("want %d themes, got %d", len(want), len(themes))
	}
	for i, id := range want {
		if themes[i].ID != id {
			t.Fatalf("themes[%d].ID = %q, want %q", i, themes[i].ID, id)
		}
	}
}

func TestApplyEachThemeWritesStarship(t *testing.T) {
	for _, id := range []string{"catppuccin", "dracula", "nord", "tokyonight"} {
		id := id
		t.Run(id, func(t *testing.T) {
			home := t.TempDir()
			t.Setenv("HOME", home)
			if err := Apply(config.Config{}, id); err != nil {
				t.Fatal(err)
			}
			data, err := os.ReadFile(filepath.Join(home, ".config", "starship.toml"))
			if err != nil {
				t.Fatal(err)
			}
			if len(data) == 0 {
				t.Fatal("empty starship.toml")
			}
		})
	}
}