package installer

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

	"gitgud.io/mike/mpv-manager/pkg/constants"
	"gitgud.io/mike/mpv-manager/pkg/platform"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestPreserveUserSettings(t *testing.T) {
	t.Run("parses all supported keys", func(t *testing.T) {
		configPath := filepath.Join(t.TempDir(), "mpv.conf")
		content := `# comment line

alang=ja, en ,de
slang=eng
hwdec=nvdec
vo=gpu-next
scale=ewa_lanczossharp
dither-depth-convert=no
unrelated-key=yes
malformed-line-without-equals
`
		require.NoError(t, os.WriteFile(configPath, []byte(content), 0644))
		cr, out := newBufferedRunner()

		settings, err := PreserveUserSettings(configPath, cr)
		require.NoError(t, err)
		assert.Equal(t, []string{"ja", "en", "de"}, settings.AudioLanguages)
		assert.Equal(t, []string{"eng"}, settings.SubtitleLanguages)
		assert.Equal(t, "nvdec", settings.HardwareDecoder)
		assert.Equal(t, "gpu-next", settings.VideoOutput)
		assert.Equal(t, "ewa_lanczossharp", settings.ScaleFilter)
		assert.Equal(t, "no", settings.DitherAlgorithm)
		assert.Contains(t, drainOutput(out), "Preserved 6 user setting(s)")
	})

	t.Run("missing config yields empty settings", func(t *testing.T) {
		cr, out := newBufferedRunner()
		settings, err := PreserveUserSettings(filepath.Join(t.TempDir(), "mpv.conf"), cr)
		require.NoError(t, err)
		require.NotNil(t, settings)
		assert.Equal(t, 0, countNonEmptySettings(settings))
		assert.Contains(t, drainOutput(out), "No existing mpv.conf found, will use defaults")
	})

	t.Run("nil runner is accepted", func(t *testing.T) {
		settings, err := PreserveUserSettings(filepath.Join(t.TempDir(), "mpv.conf"), nil)
		require.NoError(t, err)
		assert.NotNil(t, settings)
	})
}

func TestApplyUserSettings(t *testing.T) {
	t.Run("updates existing keys and appends missing ones", func(t *testing.T) {
		configPath := filepath.Join(t.TempDir(), "mpv.conf")
		original := "# header comment\nhwdec=auto\nvo=gpu\nkeep-this=yes\n"
		require.NoError(t, os.WriteFile(configPath, []byte(original), 0644))

		settings := &UserSettings{
			AudioLanguages:    []string{"de", "en"},
			SubtitleLanguages: []string{"deu"},
			HardwareDecoder:   "nvdec",
			VideoOutput:       "gpu-next",
			ScaleFilter:       "spline36",
			DitherAlgorithm:   "yes",
		}
		cr, out := newBufferedRunner()

		require.NoError(t, ApplyUserSettings(configPath, settings, cr))

		data, err := os.ReadFile(configPath)
		require.NoError(t, err)
		conf := string(data)
		assert.Contains(t, conf, "# header comment")
		assert.Contains(t, conf, "keep-this=yes")
		assert.Contains(t, conf, "hwdec=nvdec")
		assert.Contains(t, conf, "vo=gpu-next")
		assert.Contains(t, conf, "alang=de,en")
		assert.Contains(t, conf, "slang=deu")
		assert.Contains(t, conf, "scale=spline36")
		assert.Contains(t, conf, "dither-depth-convert=yes")
		assert.NotContains(t, conf, "hwdec=auto")

		outputs := drainOutput(out)
		assert.Contains(t, outputs, "User settings applied successfully!")
	})

	t.Run("empty settings leave the file content unchanged", func(t *testing.T) {
		configPath := filepath.Join(t.TempDir(), "mpv.conf")
		original := "hwdec=vulkan\n"
		require.NoError(t, os.WriteFile(configPath, []byte(original), 0644))

		cr, _ := newBufferedRunner()
		require.NoError(t, ApplyUserSettings(configPath, &UserSettings{}, cr))

		data, err := os.ReadFile(configPath)
		require.NoError(t, err)
		assert.Equal(t, original, string(data))
	})

	t.Run("rejects invalid parameters", func(t *testing.T) {
		cr, _ := newBufferedRunner()
		require.Error(t, ApplyUserSettings("whatever", nil, cr))
		require.Error(t, ApplyUserSettings("whatever", &UserSettings{}, nil))
	})

	t.Run("missing config file fails", func(t *testing.T) {
		cr, _ := newBufferedRunner()
		err := ApplyUserSettings(filepath.Join(t.TempDir(), "mpv.conf"), &UserSettings{}, cr)
		require.Error(t, err)
		assert.Contains(t, err.Error(), "failed to read config file")
	})
}

func TestSetRecommendedHWADecoderIfEmpty(t *testing.T) {
	nvidia := &platform.GPUInfo{Brand: "nvidia"}
	recommended := platform.GetRecommendedHWADecoder(platform.Linux, nvidia.Brand, platform.GetGPUBrands(nvidia)...)
	require.NotEmpty(t, recommended)
	require.NotEqual(t, "auto", recommended, "test assumes a concrete Linux/Nvidia recommendation")

	t.Run("replaces the auto fallback", func(t *testing.T) {
		configPath := filepath.Join(t.TempDir(), "mpv.conf")
		require.NoError(t, os.WriteFile(configPath, []byte("hwdec=auto # safe fallback\n"), 0644))
		cr, out := newBufferedRunner()

		require.NoError(t, SetRecommendedHWADecoderIfEmpty(configPath, platform.Linux, nvidia, cr))

		data, err := os.ReadFile(configPath)
		require.NoError(t, err)
		assert.Contains(t, string(data), "hwdec="+recommended)
		assert.Contains(t, drainOutput(out), "Set recommended hardware decoder: "+recommended)
	})

	t.Run("keeps a custom user value", func(t *testing.T) {
		configPath := filepath.Join(t.TempDir(), "mpv.conf")
		require.NoError(t, os.WriteFile(configPath, []byte("hwdec=vulkan\n"), 0644))
		cr, _ := newBufferedRunner()

		require.NoError(t, SetRecommendedHWADecoderIfEmpty(configPath, platform.Linux, nvidia, cr))

		data, err := os.ReadFile(configPath)
		require.NoError(t, err)
		assert.Equal(t, "hwdec=vulkan\n", string(data))
	})

	t.Run("adds hwdec when missing", func(t *testing.T) {
		configPath := filepath.Join(t.TempDir(), "mpv.conf")
		require.NoError(t, os.WriteFile(configPath, []byte("vo=gpu-next\n"), 0644))
		cr, _ := newBufferedRunner()

		require.NoError(t, SetRecommendedHWADecoderIfEmpty(configPath, platform.Linux, nvidia, cr))

		data, err := os.ReadFile(configPath)
		require.NoError(t, err)
		assert.Contains(t, string(data), "hwdec="+recommended)
	})

	t.Run("no recommendation leaves the file alone", func(t *testing.T) {
		configPath := filepath.Join(t.TempDir(), "mpv.conf")
		original := "hwdec=auto\n"
		require.NoError(t, os.WriteFile(configPath, []byte(original), 0644))
		cr, _ := newBufferedRunner()

		// nil GPU info yields the "auto" default recommendation: nothing to do.
		require.NoError(t, SetRecommendedHWADecoderIfEmpty(configPath, platform.Linux, nil, cr))

		data, err := os.ReadFile(configPath)
		require.NoError(t, err)
		assert.Equal(t, original, string(data))
	})

	t.Run("unreadable config fails", func(t *testing.T) {
		cr, _ := newBufferedRunner()
		err := SetRecommendedHWADecoderIfEmpty(filepath.Join(t.TempDir(), "mpv.conf"), platform.Linux, nvidia, cr)
		require.Error(t, err)
		assert.Contains(t, err.Error(), "failed to read config file")
	})
}

func TestInstallMPVConfigWithPlatformDefaults(t *testing.T) {
	isolateConfig(t)

	configPath, err := GetMPVConfigPath()
	require.NoError(t, err)
	configDir := filepath.Dir(configPath)
	require.NoError(t, os.MkdirAll(configDir, 0755))
	require.NoError(t, os.WriteFile(configPath, []byte("alang=de,en\nhwdec=auto\n"), 0644))

	nvidia := &platform.GPUInfo{Brand: "nvidia"}
	recommended := platform.GetRecommendedHWADecoder(platform.Linux, nvidia.Brand, platform.GetGPUBrands(nvidia)...)

	inst := NewInstaller(ReleaseInfo{}, "")
	cr, out := newBufferedRunner()

	require.NoError(t, InstallMPVConfigWithPlatformDefaults(inst, cr, platform.Linux, nvidia))

	data, err := os.ReadFile(configPath)
	require.NoError(t, err)
	conf := string(data)
	// The embedded default config was installed, user languages were preserved,
	// and the recommended decoder replaced the auto fallback.
	assert.Contains(t, conf, "profile=high-quality")
	assert.Contains(t, conf, "alang=de,en")
	if recommended != "" && recommended != "auto" {
		assert.Contains(t, conf, "hwdec="+recommended)
	}

	// The previous config was backed up into conf_backups.
	backupDir, err := GetConfigBackupDir()
	require.NoError(t, err)
	entries, err := os.ReadDir(backupDir)
	require.NoError(t, err)
	assert.NotEmpty(t, entries)

	outputs := drainOutput(out)
	assert.Contains(t, outputs, "MPV configuration installed successfully!")
}

func TestInstallMPVConfigWithOutput_BackupFailureAbortsWithoutChangingLiveConfig(t *testing.T) {
	isolateConfig(t)

	configPath, err := GetMPVConfigPath()
	require.NoError(t, err)
	configDir := filepath.Dir(configPath)

	// A regular file where the backup directory should be forces
	// CreateFullBackup to fail; installation must leave the live file intact.
	require.NoError(t, os.MkdirAll(configDir, 0755))
	require.NoError(t, os.WriteFile(filepath.Join(configDir, constants.ConfigBackupsDir), []byte("blocker"), 0644))
	require.NoError(t, os.WriteFile(configPath, []byte("alang=ja\n"), 0644))

	inst := NewInstaller(ReleaseInfo{}, "")
	cr, out := newBufferedRunner()

	require.Error(t, inst.InstallMPVConfigWithOutput(cr))
	assert.NotContains(t, drainOutput(out), "MPV configuration installed successfully!")

	data, err := os.ReadFile(configPath)
	require.NoError(t, err)
	assert.Equal(t, "alang=ja\n", string(data))
}