package config

import (
	"encoding/hex"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"

	"github.com/pelletier/go-toml/v2"
)

func TestDefaultConfigData(t *testing.T) {
	data := DefaultConfigData()
	if data.Misc.Version != CurrentConfigVersion {
		t.Fatalf("version = %q, want %q", data.Misc.Version, CurrentConfigVersion)
	}
	if data.Downloads.Folder == "" {
		t.Fatalf("downloads folder should not be empty")
	}
	if data.Database.DownloadsPath == "" || data.Database.FailedDownloadsPath == "" {
		t.Fatalf("database paths should not be empty")
	}
}

func TestLoadCreatesDefaultConfigWhenMissing(t *testing.T) {
	tmpDir := t.TempDir()
	path := filepath.Join(tmpDir, "config.toml")

	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("Load() error = %v", err)
	}

	if cfg.Path != path {
		t.Fatalf("path = %q, want %q", cfg.Path, path)
	}
	if _, err = os.Stat(path); err != nil {
		t.Fatalf("expected created config file: %v", err)
	}
}

func TestLoadOutdatedConfig(t *testing.T) {
	tmpDir := t.TempDir()
	path := filepath.Join(tmpDir, "config.toml")

	data := DefaultConfigData()
	data.Misc.Version = "1.0.0"
	if err := saveConfigData(path, data); err != nil {
		t.Fatalf("saveConfigData() error = %v", err)
	}

	_, err := Load(path)
	if !errors.Is(err, ErrOutdatedConfig) {
		t.Fatalf("Load() error = %v, want ErrOutdatedConfig", err)
	}
}

func TestUpgradeOutdatedConfig(t *testing.T) {
	tmpDir := t.TempDir()
	path := filepath.Join(tmpDir, "config.toml")

	data := DefaultConfigData()
	data.Misc.Version = "1.0.0"
	data.Downloads.Folder = filepath.Join(tmpDir, "Music")
	if err := saveConfigData(path, data); err != nil {
		t.Fatalf("saveConfigData() error = %v", err)
	}

	resolved, err := UpgradeOutdated(path)
	if err != nil {
		t.Fatalf("UpgradeOutdated() error = %v", err)
	}
	if resolved != path {
		t.Fatalf("resolved path = %q, want %q", resolved, path)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("Load() after upgrade error = %v", err)
	}
	if cfg.File.Misc.Version != CurrentConfigVersion {
		t.Fatalf("version = %q, want %q", cfg.File.Misc.Version, CurrentConfigVersion)
	}
	if cfg.File.Downloads.Folder != data.Downloads.Folder {
		t.Fatalf("downloads folder changed unexpectedly")
	}
}

func TestSessionCloneDoesNotAliasSlices(t *testing.T) {
	tmpDir := t.TempDir()
	path := filepath.Join(tmpDir, "config.toml")

	data := DefaultConfigData()
	data.Metadata.Exclude = []string{"lyrics"}
	data.Qobuz.Secrets = []string{"s1"}
	if err := saveConfigData(path, data); err != nil {
		t.Fatalf("saveConfigData() error = %v", err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatalf("Load() error = %v", err)
	}

	cfg.Session.Metadata.Exclude[0] = "comment"
	cfg.Session.Qobuz.Secrets[0] = "s2"

	if cfg.File.Metadata.Exclude[0] != "lyrics" {
		t.Fatalf("file metadata exclude unexpectedly mutated")
	}
	if cfg.File.Qobuz.Secrets[0] != "s1" {
		t.Fatalf("file qobuz secrets unexpectedly mutated")
	}
}

func TestDefaultConfigPassesValidation(t *testing.T) {
	d := DefaultConfigData()
	applyRuntimeDefaults(&d)
	if err := Validate(&d); err != nil {
		t.Fatalf("shipped defaults fail validation: %v", err)
	}
}

// TestExampleConfigIsValid guards the file users are told to copy.
func TestExampleConfigIsValid(t *testing.T) {
	raw, err := os.ReadFile(filepath.Join("..", "..", "config.toml.example"))
	if err != nil {
		t.Skipf("example config not found: %v", err)
	}
	data := DefaultConfigData()
	if err := toml.Unmarshal(raw, &data); err != nil {
		t.Fatalf("config.toml.example does not parse: %v", err)
	}
	applyRuntimeDefaults(&data)
	if err := Validate(&data); err != nil {
		t.Fatalf("config.toml.example fails validation: %v", err)
	}
	if data.Misc.Version != CurrentConfigVersion {
		t.Errorf("config.toml.example version = %q, want %q", data.Misc.Version, CurrentConfigVersion)
	}
}

func TestValidateRejectsBadValues(t *testing.T) {
	tests := []struct {
		name   string
		mutate func(*ConfigData)
		want   string
	}{
		{"qobuz quality 0", func(d *ConfigData) { d.Qobuz.Quality = 0 }, "qobuz.quality"},
		{"qobuz quality 5", func(d *ConfigData) { d.Qobuz.Quality = 5 }, "qobuz.quality"},
		{"beatport quality 0", func(d *ConfigData) { d.Beatport.Quality = 0 }, "beatport.quality"},
		{"tidal quality 5", func(d *ConfigData) { d.Tidal.Quality = 5 }, "tidal.quality"},
		{"negative quality", func(d *ConfigData) { d.Tidal.Quality = -1 }, "tidal.quality"},
		{"max_connections 0", func(d *ConfigData) { d.Downloads.MaxConnections = 0 }, "max_connections"},
		{"max_connections negative", func(d *ConfigData) { d.Downloads.MaxConnections = -5 }, "max_connections"},
		{"requests_per_minute 0", func(d *ConfigData) { d.Downloads.RequestsPerMinute = 0 }, "requests_per_minute"},
		{"truncate_to 0", func(d *ConfigData) { d.Filepaths.TruncateTo = 0 }, "truncate_to"},
		{"bogus codec", func(d *ConfigData) {
			d.Conversion.Enabled = true
			d.Conversion.Codec = "bogus"
		}, "conversion.codec"},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			d := DefaultConfigData()
			applyRuntimeDefaults(&d)
			tc.mutate(&d)
			err := Validate(&d)
			if err == nil {
				t.Fatalf("Validate() = nil, want an error mentioning %q", tc.want)
			}
			if !strings.Contains(err.Error(), tc.want) {
				t.Fatalf("Validate() = %q, want it to mention %q", err, tc.want)
			}
		})
	}
}

// TestValidateAcceptsDocumentedQualityValues pins the ranges documented in
// config.toml.example. An earlier draft capped deezer at 2 and soundcloud at 1,
// which would have made a config the example itself documents fail to load.
func TestValidateAcceptsDocumentedQualityValues(t *testing.T) {
	for q := 0; q <= 4; q++ {
		d := DefaultConfigData()
		applyRuntimeDefaults(&d)
		d.Deezer.Quality = q
		d.Soundcloud.Quality = q
		d.Tidal.Quality = q
		d.Yandex.Quality = q
		if err := Validate(&d); err != nil {
			t.Errorf("quality %d rejected: %v", q, err)
		}
	}
	// Qobuz and Beatport have no tier 0.
	for q := 1; q <= 4; q++ {
		d := DefaultConfigData()
		applyRuntimeDefaults(&d)
		d.Qobuz.Quality = q
		d.Beatport.Quality = q
		if err := Validate(&d); err != nil {
			t.Errorf("qobuz/beatport quality %d rejected: %v", q, err)
		}
	}
}

func TestValidateAcceptsValidValues(t *testing.T) {
	d := DefaultConfigData()
	applyRuntimeDefaults(&d)
	// Negative requests_per_minute disables throttling, which is legitimate.
	d.Downloads.RequestsPerMinute = -1
	d.Soundcloud.Quality = 1
	d.Deezer.Quality = 4
	d.Qobuz.Quality = 4
	if err := Validate(&d); err != nil {
		t.Fatalf("Validate() = %v, want nil", err)
	}
}

func TestValidateNormalizesCodec(t *testing.T) {
	d := DefaultConfigData()
	applyRuntimeDefaults(&d)
	d.Conversion.Enabled = true
	d.Conversion.Codec = "  ogg  "
	if err := Validate(&d); err != nil {
		t.Fatalf("Validate() = %v", err)
	}
	if d.Conversion.Codec != "VORBIS" {
		t.Fatalf("codec = %q, want VORBIS", d.Conversion.Codec)
	}
}

func TestNormalizeCodec(t *testing.T) {
	for in, want := range map[string]string{
		"flac": "FLAC", "FLAC": "FLAC", " mp3 ": "MP3",
		"ogg": "VORBIS", "vorbis": "VORBIS", "alac": "ALAC", "aac": "AAC",
	} {
		got, err := NormalizeCodec(in)
		if err != nil {
			t.Errorf("NormalizeCodec(%q) err = %v", in, err)
			continue
		}
		if got != want {
			t.Errorf("NormalizeCodec(%q) = %q, want %q", in, got, want)
		}
	}
	if _, err := NormalizeCodec("wav"); err == nil {
		t.Error("NormalizeCodec(wav) should fail")
	}
}

func TestCloneConfigDataDoesNotShareSlices(t *testing.T) {
	a := DefaultConfigData()
	a.Qobuz.Secrets = []string{"s1", "s2"}
	a.Metadata.Exclude = []string{"e1"}

	b := CloneConfigData(a)
	b.Qobuz.Secrets[0] = "mutated"
	b.Metadata.Exclude[0] = "mutated"

	if a.Qobuz.Secrets[0] != "s1" {
		t.Error("Qobuz.Secrets is shared between copies")
	}
	if a.Metadata.Exclude[0] != "e1" {
		t.Error("Metadata.Exclude is shared between copies")
	}
}

func TestSaveFileUsesOwnerOnlyPermissions(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "config.toml")
	cfg := &Config{Path: path, File: DefaultConfigData()}
	if err := cfg.SaveFile(); err != nil {
		t.Fatalf("SaveFile() = %v", err)
	}
	info, err := os.Stat(path)
	if err != nil {
		t.Fatal(err)
	}
	// The file holds plaintext passwords, ARL cookies and OAuth tokens.
	if perm := info.Mode().Perm(); perm != 0o600 {
		t.Fatalf("config permissions = %04o, want 0600", perm)
	}
}

func TestSaveFileTightensExistingWorldReadableFile(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "config.toml")
	if err := os.WriteFile(path, []byte("version = \"x\"\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	cfg := &Config{Path: path, File: DefaultConfigData()}
	if err := cfg.SaveFile(); err != nil {
		t.Fatal(err)
	}
	info, err := os.Stat(path)
	if err != nil {
		t.Fatal(err)
	}
	if perm := info.Mode().Perm(); perm != 0o600 {
		t.Fatalf("permissions = %04o, want 0600 after rewrite", perm)
	}
}

func TestUpdateTokensIsSafeWithoutAPath(t *testing.T) {
	cfg := &Config{File: DefaultConfigData(), Session: DefaultConfigData()}
	err := cfg.UpdateTokens(func(file, session *ConfigData) {
		file.Deezer.RefreshToken = "rt"
		session.Deezer.RefreshToken = "rt"
	})
	if err != nil {
		t.Fatalf("UpdateTokens() = %v", err)
	}
	// The in-memory update must still happen even with nothing to write to.
	if cfg.File.Deezer.RefreshToken != "rt" || cfg.Session.Deezer.RefreshToken != "rt" {
		t.Fatal("UpdateTokens did not apply the mutation")
	}
}

func TestUpdateTokensPersistsAndIsConcurrencySafe(t *testing.T) {
	path := filepath.Join(t.TempDir(), "config.toml")
	cfg := &Config{Path: path, File: DefaultConfigData(), Session: DefaultConfigData()}

	var wg sync.WaitGroup
	for i := 0; i < 16; i++ {
		wg.Add(1)
		go func(n int) {
			defer wg.Done()
			token := fmt.Sprintf("token-%d", n)
			if err := cfg.UpdateTokens(func(file, session *ConfigData) {
				file.Tidal.AccessToken = token
				session.Tidal.AccessToken = token
			}); err != nil {
				t.Errorf("UpdateTokens: %v", err)
			}
		}(i)
	}
	wg.Wait()

	raw, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	var round ConfigData
	if err := toml.Unmarshal(raw, &round); err != nil {
		t.Fatalf("concurrent writes produced an unparseable config: %v", err)
	}
	if round.Tidal.AccessToken == "" {
		t.Error("no token persisted")
	}
}

// TestVendorDefaultsAreApplied guards the Phase-3 move of vendor credentials
// into config: an empty value must resolve to the built-in constant, or the
// providers silently authenticate and sign with empty keys.
func TestVendorDefaultsAreApplied(t *testing.T) {
	d := DefaultConfigData()
	checks := map[string]string{
		"qobuz.mobile_app_id":     d.Qobuz.MobileAppID,
		"qobuz.mobile_app_secret": d.Qobuz.MobileAppSecret,
		"tidal.app_client_id":     d.Tidal.AppClientID,
		"tidal.app_client_secret": d.Tidal.AppClientSecret,
		"deezer.api_key":          d.Deezer.APIKey,
		"deezer.gateway_key":      d.Deezer.GatewayKey,
		"deezer.blowfish_secret":  d.Deezer.BlowfishSecret,
		"yandex.sign_key":         d.Yandex.SignKey,
		"yandex.legacy_sign_salt": d.Yandex.LegacyMP3SignSalt,
		"beatport.app_client_id":  d.Beatport.AppClientID,
	}
	for name, got := range checks {
		if got == "" {
			t.Errorf("%s is empty in DefaultConfigData()", name)
		}
	}

	// An explicitly empty config must be backfilled too, since that is what a
	// user config written before these keys existed looks like.
	var blank ConfigData
	applyVendorDefaults(&blank)
	if blank.Qobuz.MobileAppSecret != DefaultQobuzMobileAppSecret {
		t.Error("applyVendorDefaults did not backfill qobuz.mobile_app_secret")
	}
	if blank.Deezer.BlowfishSecret != DefaultDeezerBlowfishSecret {
		t.Error("applyVendorDefaults did not backfill deezer.blowfish_secret")
	}
}

func TestVendorDefaultsAreNotOverriddenWhenSet(t *testing.T) {
	d := ConfigData{}
	d.Tidal.AppClientID = "mine"
	d.Deezer.BlowfishSecret = "0123456789abcdef"
	applyVendorDefaults(&d)
	if d.Tidal.AppClientID != "mine" {
		t.Errorf("user value overwritten: %q", d.Tidal.AppClientID)
	}
	if d.Deezer.BlowfishSecret != "0123456789abcdef" {
		t.Errorf("user value overwritten: %q", d.Deezer.BlowfishSecret)
	}
}

// TestDeezerBlowfishSecretLength pins the length the key derivation depends
// on: it XORs 16 bytes, so a different length would panic or silently derive a
// wrong key.
func TestDeezerBlowfishSecretLength(t *testing.T) {
	if got := len(DefaultDeezerBlowfishSecret); got != 16 {
		t.Fatalf("DefaultDeezerBlowfishSecret is %d bytes, want 16", got)
	}
}

// TestQobuzMobileAppSecretIsHex pins the format the HKDF step requires.
func TestQobuzMobileAppSecretIsHex(t *testing.T) {
	if _, err := hex.DecodeString(DefaultQobuzMobileAppSecret); err != nil {
		t.Fatalf("DefaultQobuzMobileAppSecret is not hex: %v", err)
	}
}