package playlists

import (
	"testing"

	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

func strPtr(s string) *string { return &s }

func TestDedupeCollageRows_DropsDuplicates(t *testing.T) {
	rows := []dbq.ListAllPlaylistTracksForCollageRow{
		{Position: 0, AlbumCoverPath: strPtr("a.jpg")},
		{Position: 1, AlbumCoverPath: strPtr("a.jpg")}, // dup → drop
		{Position: 2, AlbumCoverPath: strPtr("b.jpg")},
		{Position: 3, AlbumCoverPath: strPtr("a.jpg")}, // dup → drop
		{Position: 4, AlbumCoverPath: strPtr("c.jpg")},
		{Position: 5, AlbumCoverPath: strPtr("d.jpg")},
		{Position: 6, AlbumCoverPath: strPtr("e.jpg")}, // beyond max=4 → drop
	}
	got := dedupeCollageRows(rows, 4)
	if len(got) != 4 {
		t.Fatalf("len = %d, want 4", len(got))
	}
	wantPaths := []string{"a.jpg", "b.jpg", "c.jpg", "d.jpg"}
	for i, w := range wantPaths {
		if got[i].AlbumCoverPath == nil || *got[i].AlbumCoverPath != w {
			t.Errorf("got[%d].AlbumCoverPath = %v, want %q", i, got[i].AlbumCoverPath, w)
		}
	}
}

func TestDedupeCollageRows_NullCoversNotDeduped(t *testing.T) {
	// NULL covers each render the fallback glyph in their own cell.
	// They shouldn't dedupe against each other; the playlist with all
	// missing covers should still produce 4 cells.
	rows := []dbq.ListAllPlaylistTracksForCollageRow{
		{Position: 0, AlbumCoverPath: nil},
		{Position: 1, AlbumCoverPath: nil},
		{Position: 2, AlbumCoverPath: nil},
		{Position: 3, AlbumCoverPath: nil},
	}
	got := dedupeCollageRows(rows, 4)
	if len(got) != 4 {
		t.Errorf("len = %d, want 4 (nil covers shouldn't dedupe)", len(got))
	}
}

func TestDedupeCollageRows_EmptyStringCoverNotDeduped(t *testing.T) {
	// An empty-string cover_art_path is treated the same as NULL —
	// renders the glyph fallback. Should not dedupe.
	empty := ""
	rows := []dbq.ListAllPlaylistTracksForCollageRow{
		{Position: 0, AlbumCoverPath: &empty},
		{Position: 1, AlbumCoverPath: &empty},
	}
	got := dedupeCollageRows(rows, 4)
	if len(got) != 2 {
		t.Errorf("len = %d, want 2", len(got))
	}
}

func TestDedupeCollageRows_PreservesPositionOrder(t *testing.T) {
	rows := []dbq.ListAllPlaylistTracksForCollageRow{
		{Position: 0, AlbumCoverPath: strPtr("z.jpg")},
		{Position: 1, AlbumCoverPath: strPtr("a.jpg")},
		{Position: 2, AlbumCoverPath: strPtr("m.jpg")},
	}
	got := dedupeCollageRows(rows, 4)
	if len(got) != 3 {
		t.Fatalf("len = %d, want 3", len(got))
	}
	// First-seen wins; original input order is preserved (z, a, m).
	wantPaths := []string{"z.jpg", "a.jpg", "m.jpg"}
	for i, w := range wantPaths {
		if got[i].AlbumCoverPath == nil || *got[i].AlbumCoverPath != w {
			t.Errorf("got[%d] = %v, want %q", i, got[i].AlbumCoverPath, w)
		}
	}
}

func TestDedupeCollageRows_MixedNullAndDups(t *testing.T) {
	// Mixed: a few NULL covers + dup non-NULL. NULLs always pass;
	// non-NULL dedups.
	rows := []dbq.ListAllPlaylistTracksForCollageRow{
		{Position: 0, AlbumCoverPath: strPtr("a.jpg")},
		{Position: 1, AlbumCoverPath: nil},
		{Position: 2, AlbumCoverPath: strPtr("a.jpg")}, // dup of [0] → drop
		{Position: 3, AlbumCoverPath: nil},
		{Position: 4, AlbumCoverPath: strPtr("b.jpg")},
	}
	got := dedupeCollageRows(rows, 4)
	if len(got) != 4 {
		t.Fatalf("len = %d, want 4", len(got))
	}
	// Expected: a.jpg, nil, nil, b.jpg
	if got[0].AlbumCoverPath == nil || *got[0].AlbumCoverPath != "a.jpg" {
		t.Errorf("got[0] = %v, want a.jpg", got[0].AlbumCoverPath)
	}
	if got[1].AlbumCoverPath != nil {
		t.Errorf("got[1] = %v, want nil", got[1].AlbumCoverPath)
	}
	if got[2].AlbumCoverPath != nil {
		t.Errorf("got[2] = %v, want nil", got[2].AlbumCoverPath)
	}
	if got[3].AlbumCoverPath == nil || *got[3].AlbumCoverPath != "b.jpg" {
		t.Errorf("got[3] = %v, want b.jpg", got[3].AlbumCoverPath)
	}
}