package musicbrainz

import (
	"context"
	"net/http"
	"net/http/httptest"
	"testing"

	"golang.org/x/time/rate"
	"naviwatcher/internal/config"
)

// ---------- FilterReleaseGroups tests ----------

func TestFilterReleaseGroups_ExcludesBootlegPromotionPseudo(t *testing.T) {
	groups := []ReleaseGroup{
		{ID: "rg-1", Title: "Official Album", Type: "Album", Status: "Official"},
		{ID: "rg-2", Title: "Bootleg Live", Type: "Album", Status: "Bootleg"},
		{ID: "rg-3", Title: "Promo CD", Type: "Single", Status: "Promotion"},
		{ID: "rg-4", Title: "Pseudo Release", Type: "Album", Status: "Pseudo-Release"},
	}

	result := FilterReleaseGroups(groups)

	if len(result) != 1 {
		t.Fatalf("FilterReleaseGroups() returned %d groups, want 1", len(result))
	}
	if result[0].ID != "rg-1" {
		t.Errorf("FilterReleaseGroups()[0].ID = %q, want %q", result[0].ID, "rg-1")
	}
}

func TestFilterReleaseGroups_IncludesOnlyAllowedTypes(t *testing.T) {
	groups := []ReleaseGroup{
		{ID: "rg-1", Title: "Album", Type: "Album", Status: "Official"},
		{ID: "rg-2", Title: "Single", Type: "Single", Status: "Official"},
		{ID: "rg-3", Title: "EP", Type: "EP", Status: "Official"},
		{ID: "rg-4", Title: "Compilation", Type: "Compilation", Status: "Official"},
		{ID: "rg-5", Title: "Soundtrack", Type: "Soundtrack", Status: "Official"},
		{ID: "rg-6", Title: "Live", Type: "Live", Status: "Official"},
		{ID: "rg-7", Title: "Remix", Type: "Remix", Status: "Official"},
	}

	result := FilterReleaseGroups(groups)

	if len(result) != 4 {
		t.Fatalf("FilterReleaseGroups() returned %d groups, want 4", len(result))
	}

	allowedIDs := map[string]bool{"rg-1": true, "rg-2": true, "rg-3": true, "rg-4": true}
	for _, rg := range result {
		if !allowedIDs[rg.ID] {
			t.Errorf("unexpected group %q in filtered results", rg.ID)
		}
	}
}

// ---------- NormalizeString tests ----------

func TestNormalizeString_Basic(t *testing.T) {
	tests := []struct {
		input    string
		expected string
	}{
		// Lowercase conversion
		{"DARK SIDE OF THE MOON", "dark side of the moon"},
		// Special character removal
		{"Dark Side of the Moon!", "dark side of the moon"},
		{"Dark-Side-of-the-Moon", "dark side of the moon"},
		{"Dark_Side_of_the_Moon", "dark side of the moon"},
		// Bracket removal
		{"Dark Side of the Moon [Deluxe Edition]", "dark side of the moon"},
		{"Dark Side of the Moon [Remastered 2020]", "dark side of the moon"},
		{"Album [2023 Remix]", "album"},
		// Parenthesis removal
		{"Dark Side of the Moon (Deluxe)", "dark side of the moon"},
		{"Album (Remastered)", "album"},
		// Year removal
		{"Dark Side of the Moon 1973", "dark side of the moon"},
		{"Album 2020 Remastered", "album remastered"},
		// Space collapsing
		{"Dark   Side   of   the   Moon", "dark side of the moon"},
		// Trim
		{"  Dark Side of the Moon  ", "dark side of the moon"},
		// Combined
		{"The Dark Side of the Moon [2011 Remaster] (Deluxe Edition)", "the dark side of the moon"},
		// Empty
		{"", ""},
		// Only special chars
		{"!@#$%^&*()", ""},
		// Digits that are not years should stay
		{"30 Seconds to Mars", "30 seconds to mars"},
		{"1941 - The Greatest Hits", "the greatest hits"},
	}

	for _, tt := range tests {
		t.Run(tt.input, func(t *testing.T) {
			got := NormalizeString(tt.input)
			if got != tt.expected {
				t.Errorf("NormalizeString(%q) = %q, want %q", tt.input, got, tt.expected)
			}
		})
	}
}

func TestNormalizeArtistName(t *testing.T) {
	tests := []struct {
		input    string
		expected string
	}{
		{"Pink Floyd", "pink floyd"},
		{"The Beatles", "beatles"},
		{"A Perfect Circle", "perfect circle"},
		{"An Orchestra", "orchestra"},
		{"  The  Who  ", "who"},
		{"THE WHO", "who"},
		// No stripping needed
		{"Radiohead", "radiohead"},
		// Already stripped
		{"Beatles", "beatles"},
	}

	for _, tt := range tests {
		t.Run(tt.input, func(t *testing.T) {
			got := NormalizeArtistName(tt.input)
			if got != tt.expected {
				t.Errorf("NormalizeArtistName(%q) = %q, want %q", tt.input, got, tt.expected)
			}
		})
	}
}

// ---------- ReleaseGroup.ToExternalRelease tests ----------

func TestReleaseGroup_ToExternalRelease(t *testing.T) {
	rg := ReleaseGroup{
		ID:          "rg-uuid-1",
		Title:       "Dark Side of the Moon",
		Type:        "Album",
		Status:      "Official",
		ArtistID:    "artist-uuid-1",
		ArtistName:  "Pink Floyd",
		ReleaseDate: "1973-03-01",
	}

	er := rg.ToExternalRelease()

	if er.RGID != "rg-uuid-1" {
		t.Errorf("RGID = %q, want %q", er.RGID, "rg-uuid-1")
	}
	if er.ArtistID != "artist-uuid-1" {
		t.Errorf("ArtistID = %q, want %q", er.ArtistID, "artist-uuid-1")
	}
	if er.Title != "Dark Side of the Moon" {
		t.Errorf("Title = %q, want %q", er.Title, "Dark Side of the Moon")
	}
	if er.Type != "Album" {
		t.Errorf("Type = %q, want %q", er.Type, "Album")
	}
	if er.ReleaseDate != "1973-03-01" {
		t.Errorf("ReleaseDate = %q, want %q", er.ReleaseDate, "1973-03-01")
	}
}

// ---------- GetArtistReleaseGroups tests ----------

func TestGetArtistReleaseGroups_Success(t *testing.T) {
	artistMBID := "artist-uuid-test"

	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/xml")
		w.Write([]byte(`<?xml version="1.0" encoding="UTF-8"?>
<metadata xmlns="http://musicbrainz.org/ns/mmd-2.0#">
  <release-group-list count="2">
    <release-group id="rg-uuid-1" type="Album">
      <title>Dark Side of the Moon</title>
      <first-release-date>1973-03-01</first-release-date>
      <artist-credit>
        <name-credit>
          <artist id="` + artistMBID + `">
            <name>Pink Floyd</name>
          </artist>
        </name-credit>
      </artist-credit>
    </release-group>
    <release-group id="rg-uuid-2" type="Single">
      <title>Another Brick in the Wall</title>
      <first-release-date>1979-11-30</first-release-date>
      <artist-credit>
        <name-credit>
          <artist id="` + artistMBID + `">
            <name>Pink Floyd</name>
          </artist>
        </name-credit>
      </artist-credit>
    </release-group>
  </release-group-list>
</metadata>`))
	}))
	defer server.Close()

	cfg := config.MusicBrainzConfig{
		UserAgent: "naviwatcher/0.1.0 (test@example.com)",
	}

	rl := rate.NewLimiter(rate.Limit(1000), 1000)
	client := &MusicBrainzClient{
		httpClient:  server.Client(),
		userAgent:   cfg.UserAgent,
		baseURL:     server.URL,
		rateLimiter: rl,
	}

	groups, err := client.GetArtistReleaseGroups(context.Background(), artistMBID)
	if err != nil {
		t.Fatalf("GetArtistReleaseGroups() error = %v", err)
	}

	if len(groups) != 2 {
		t.Fatalf("GetArtistReleaseGroups() returned %d groups, want 2", len(groups))
	}

	if groups[0].Title != "Dark Side of the Moon" {
		t.Errorf("groups[0].Title = %q, want %q", groups[0].Title, "Dark Side of the Moon")
	}
	if groups[1].Title != "Another Brick in the Wall" {
		t.Errorf("groups[1].Title = %q, want %q", groups[1].Title, "Another Brick in the Wall")
	}
}

func TestGetArtistReleaseGroups_Pagination(t *testing.T) {
	artistMBID := "artist-page-test"
	requestCount := 0

	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestCount++
		offset := r.URL.Query().Get("offset")

		w.Header().Set("Content-Type", "application/xml")

		if offset == "0" || offset == "" {
			// First page: return 100 results (full page, matching limit) to trigger pagination
			xml := `<?xml version="1.0" encoding="UTF-8"?>
<metadata xmlns="http://musicbrainz.org/ns/mmd-2.0#">
  <release-group-list count="101">`
			for i := 0; i < 100; i++ {
				xml += `
    <release-group id="rg-page1-` + string(rune('0'+i%10)) + `" type="Album">
      <title>Page 1 Album</title>
      <first-release-date>2020-01-01</first-release-date>
      <artist-credit>
        <name-credit>
          <artist id="` + artistMBID + `"><name>Artist</name></artist>
        </name-credit>
      </artist-credit>
    </release-group>`
			}
			xml += `
  </release-group-list>
</metadata>`
			w.Write([]byte(xml))
		} else {
			// Second page: return only 1 result (< limit, signaling last page)
			w.Write([]byte(`<?xml version="1.0" encoding="UTF-8"?>
<metadata xmlns="http://musicbrainz.org/ns/mmd-2.0#">
  <release-group-list count="101">
    <release-group id="rg-page2" type="Album">
      <title>Page 2 Album</title>
      <first-release-date>2021-01-01</first-release-date>
      <artist-credit>
        <name-credit>
          <artist id="` + artistMBID + `"><name>Artist</name></artist>
        </name-credit>
      </artist-credit>
    </release-group>
  </release-group-list>
</metadata>`))
		}
	}))
	defer server.Close()

	cfg := config.MusicBrainzConfig{
		UserAgent: "naviwatcher/0.1.0 (test@example.com)",
	}

	rl := rate.NewLimiter(rate.Limit(1000), 1000)
	client := &MusicBrainzClient{
		httpClient:  server.Client(),
		userAgent:   cfg.UserAgent,
		baseURL:     server.URL,
		rateLimiter: rl,
	}

	groups, err := client.GetArtistReleaseGroups(context.Background(), artistMBID)
	if err != nil {
		t.Fatalf("GetArtistReleaseGroups() error = %v", err)
	}

	// Should have fetched 2 pages: 100 from first + 1 from second = 101 total
	if len(groups) != 101 {
		t.Fatalf("GetArtistReleaseGroups() returned %d groups, want 101", len(groups))
	}

	if requestCount != 2 {
		t.Errorf("expected 2 paginated requests, got %d", requestCount)
	}
}

func TestGetArtistReleaseGroups_EmptyResult(t *testing.T) {
	artistMBID := "artist-empty"

	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/xml")
		w.Write([]byte(`<?xml version="1.0" encoding="UTF-8"?>
<metadata xmlns="http://musicbrainz.org/ns/mmd-2.0#">
  <release-group-list count="0">
  </release-group-list>
</metadata>`))
	}))
	defer server.Close()

	cfg := config.MusicBrainzConfig{
		UserAgent: "naviwatcher/0.1.0 (test@example.com)",
	}

	rl := rate.NewLimiter(rate.Limit(1000), 1000)
	client := &MusicBrainzClient{
		httpClient:  server.Client(),
		userAgent:   cfg.UserAgent,
		baseURL:     server.URL,
		rateLimiter: rl,
	}

	groups, err := client.GetArtistReleaseGroups(context.Background(), artistMBID)
	if err != nil {
		t.Fatalf("GetArtistReleaseGroups() error = %v", err)
	}

	if len(groups) != 0 {
		t.Errorf("GetArtistReleaseGroups() returned %d groups, want 0", len(groups))
	}
}

func TestGetArtistReleaseGroups_ServerError(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusServiceUnavailable)
		w.Write([]byte("Rate limit exceeded"))
	}))
	defer server.Close()

	cfg := config.MusicBrainzConfig{
		UserAgent: "naviwatcher/0.1.0 (test@example.com)",
	}

	rl := rate.NewLimiter(rate.Limit(1000), 1000)
	client := &MusicBrainzClient{
		httpClient:  server.Client(),
		userAgent:   cfg.UserAgent,
		baseURL:     server.URL,
		rateLimiter: rl,
	}

	_, err := client.GetArtistReleaseGroups(context.Background(), "artist-1")
	if err == nil {
		t.Fatal("GetArtistReleaseGroups() expected error for server error, got nil")
	}
}

func TestGetArtistReleaseGroups_InvalidXML(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/xml")
		w.Write([]byte(`this is not valid xml`))
	}))
	defer server.Close()

	cfg := config.MusicBrainzConfig{
		UserAgent: "naviwatcher/0.1.0 (test@example.com)",
	}

	rl := rate.NewLimiter(rate.Limit(1000), 1000)
	client := &MusicBrainzClient{
		httpClient:  server.Client(),
		userAgent:   cfg.UserAgent,
		baseURL:     server.URL,
		rateLimiter: rl,
	}

	_, err := client.GetArtistReleaseGroups(context.Background(), "artist-1")
	if err == nil {
		t.Fatal("GetArtistReleaseGroups() expected error for invalid XML, got nil")
	}
}