package e2e

import (
	"fmt"
	"testing/fstest"

	"github.com/navidrome/navidrome/conf"
	"github.com/navidrome/navidrome/core/artwork"
	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"
)

// Disc art is a serve-time read through the library FS (no worker state row), so per-disc images
// are asserted byte-for-byte, while album-root covers are asserted on the state row.
var _ = Describe("Disc artwork resolution", func() {
	BeforeEach(func() {
		setupResolutionHarness()
	})

	When("the album is single-disc with a disc1.jpg in the only folder", func() {
		// Artist/
		// └── Album/
		//     ├── 01 - Track.mp3
		//     └── disc1.jpg            ← matched by disc*.*
		It("returns the disc1.jpg image (matched as disc*.*)", func() {
			conf.Server.DiscArtPriority = "disc*.*, cd*.*, cover.*, folder.*, front.*, embedded"
			setLayout(fstest.MapFS{
				"Artist/Album/01 - Track.mp3": trackFile(1, "Track"),
				"Artist/Album/disc1.jpg":      smallPNG("disc1-image"),
			})
			scan()
			expectDiscImage(firstAlbum(), 1, "disc1-image")
		})
	})

	When("the album has no per-disc image and no album cover", func() {
		// Artist/
		// └── Album/
		//     └── 01 - Track.mp3       (no disc or album art — nothing to serve)
		It("reports the disc lookup as unavailable", func() {
			conf.Server.DiscArtPriority = "disc*.*, cd*.*"
			conf.Server.CoverArtPriority = "cover.*, folder.*"
			setLayout(fstest.MapFS{
				"Artist/Album/01 - Track.mp3": trackFile(1, "Track"),
			})
			scan()
			Expect(serveErr(discArtID(firstAlbum(), 1))).To(MatchError(artwork.ErrUnavailable))
		})
	})

	When("the album has no per-disc image but has an album cover", func() {
		// Artist/
		// └── Album/
		//     ├── 01 - Track.mp3
		//     └── cover.jpg            ← album-level fallback (no disc art present)
		It("falls back to the album cover", func() {
			conf.Server.DiscArtPriority = "disc*.*, cd*.*"
			conf.Server.CoverArtPriority = defaultCoverPriority
			setLayout(fstest.MapFS{
				"Artist/Album/01 - Track.mp3": trackFile(1, "Track"),
				"Artist/Album/cover.jpg":      smallPNG("album-cover"),
			})
			scan()
			expectDiscImage(firstAlbum(), 1, "album-cover")
		})
	})

	When("multiple disc images exist in the same folder (disc1 vs disc10)", func() {
		// Artist/
		// └── Album/
		//     ├── 01 - Track.mp3
		//     ├── disc1.jpg            ← matches request for disc 1
		//     └── disc10.jpg
		It("matches the requested disc number, not a higher-numbered one", func() {
			conf.Server.DiscArtPriority = "disc*.*"
			setLayout(fstest.MapFS{
				"Artist/Album/01 - Track.mp3": trackFile(1, "Track"),
				"Artist/Album/disc1.jpg":      smallPNG("disc-one"),
				"Artist/Album/disc10.jpg":     smallPNG("disc-ten"),
			})
			scan()
			expectDiscImage(firstAlbum(), 1, "disc-one")
		})
	})

	When("a multi-disc album has per-disc covers", func() {
		// Artist/
		// └── Album/
		//     ├── CD1/
		//     │   ├── 01 - Track.mp3
		//     │   └── disc1.jpg        ← matches request for disc 1
		//     └── CD2/
		//         ├── 01 - Track.mp3
		//         └── disc2.jpg        ← matches request for disc 2
		It("returns the requested disc's image", func() {
			conf.Server.DiscArtPriority = "disc*.*"
			setLayout(fstest.MapFS{
				"Artist/Album/CD1/01 - Track.mp3": trackFile(1, "T1", map[string]any{"disc": "1"}),
				"Artist/Album/CD2/01 - Track.mp3": trackFile(1, "T2", map[string]any{"disc": "2"}),
				"Artist/Album/CD1/disc1.jpg":      smallPNG("disc-1"),
				"Artist/Album/CD2/disc2.jpg":      smallPNG("disc-2"),
			})
			scan()
			expectDiscImage(firstAlbum(), 2, "disc-2")
		})
	})

	// Doc scenarios from:
	// https://www.navidrome.org/docs/usage/library/artwork/#disc-cover-art
	// Default DiscArtPriority is "disc*.*, cd*.*, cover.*, folder.*, front.*, discsubtitle, embedded".
	When("a disc subfolder has a cd2.png image", func() {
		// Artist/
		// └── Album/
		//     ├── CD1/
		//     │   ├── 01 - Track.mp3
		//     │   └── disc1.jpg
		//     └── CD2/
		//         ├── 01 - Track.mp3
		//         └── cd2.png          ← matched by cd*.* for disc 2
		It("matches via the cd*.* pattern", func() {
			conf.Server.DiscArtPriority = defaultDiscPriority
			setLayout(fstest.MapFS{
				"Artist/Album/CD1/01 - Track.mp3": trackFile(1, "T1", map[string]any{"disc": "1"}),
				"Artist/Album/CD2/01 - Track.mp3": trackFile(1, "T2", map[string]any{"disc": "2"}),
				"Artist/Album/CD1/disc1.jpg":      smallPNG("disc-1"),
				"Artist/Album/CD2/cd2.png":        smallPNG("cd-2"),
			})
			scan()
			expectDiscImage(firstAlbum(), 2, "cd-2")
		})
	})

	When("a disc subfolder has cover.jpg but no disc*.*/cd*.* image", func() {
		// Artist/
		// └── Album/
		//     ├── CD1/
		//     │   ├── 01 - Track.mp3
		//     │   └── cover.jpg        ← matched by cover.* inside disc folder
		//     └── CD2/
		//         ├── 01 - Track.mp3
		//         └── cover.jpg
		It("falls through to cover.* inside the disc folder", func() {
			conf.Server.DiscArtPriority = defaultDiscPriority
			setLayout(fstest.MapFS{
				"Artist/Album/CD1/01 - Track.mp3": trackFile(1, "T1", map[string]any{"disc": "1"}),
				"Artist/Album/CD2/01 - Track.mp3": trackFile(1, "T2", map[string]any{"disc": "2"}),
				"Artist/Album/CD1/cover.jpg":      smallPNG("disc1-cover"),
				"Artist/Album/CD2/cover.jpg":      smallPNG("disc2-cover"),
			})
			scan()
			expectDiscImage(firstAlbum(), 1, "disc1-cover")
		})
	})

	When("DiscArtPriority is the empty string", func() {
		// Artist/
		// └── Album/
		//     ├── CD1/
		//     │   ├── 01 - Track.mp3
		//     │   └── disc1.jpg        (ignored — DiscArtPriority is empty)
		//     ├── CD2/
		//     │   ├── 01 - Track.mp3
		//     │   └── cd2.png          (ignored — DiscArtPriority is empty)
		//     └── cover.jpg            ← used for every disc (album-level fallback)
		It("skips every disc-level source and returns the album cover", func() {
			conf.Server.DiscArtPriority = ""
			conf.Server.CoverArtPriority = defaultCoverPriority
			setLayout(fstest.MapFS{
				"Artist/Album/CD1/01 - Track.mp3": trackFile(1, "T1", map[string]any{"disc": "1"}),
				"Artist/Album/CD2/01 - Track.mp3": trackFile(1, "T2", map[string]any{"disc": "2"}),
				"Artist/Album/CD1/disc1.jpg":      smallPNG("disc-1"),
				"Artist/Album/CD2/cd2.png":        smallPNG("cd-2"),
				"Artist/Album/cover.jpg":          smallPNG("album-cover"),
			})
			scan()

			al := firstAlbum()
			for _, n := range []int{1, 2} {
				expectDiscImage(al, n, "album-cover")
			}
		})
	})

	When("the documented multi-disc layout is used (disc1.jpg + cd2.png + album-root cover.jpg)", func() {
		// Artist/
		// └── Album/
		//     ├── disc1/
		//     │   ├── disc1.jpg        ← matched by disc*.* for disc 1
		//     │   ├── 01 - Track.mp3
		//     │   └── 02 - Track.mp3
		//     ├── disc2/
		//     │   ├── cd2.png          ← matched by cd*.* for disc 2
		//     │   ├── 01 - Track.mp3
		//     │   └── 02 - Track.mp3
		//     └── cover.jpg            (album-level fallback, unused here)
		It("matches the per-disc image for each disc", func() {
			conf.Server.DiscArtPriority = defaultDiscPriority
			conf.Server.CoverArtPriority = defaultCoverPriority
			setLayout(fstest.MapFS{
				"Artist/Album/disc1/01 - Track.mp3": trackFile(1, "T1", map[string]any{"disc": "1"}),
				"Artist/Album/disc1/02 - Track.mp3": trackFile(2, "T2", map[string]any{"disc": "1"}),
				"Artist/Album/disc2/01 - Track.mp3": trackFile(1, "T3", map[string]any{"disc": "2"}),
				"Artist/Album/disc2/02 - Track.mp3": trackFile(2, "T4", map[string]any{"disc": "2"}),
				"Artist/Album/disc1/disc1.jpg":      smallPNG("disc-1"),
				"Artist/Album/disc2/cd2.png":        smallPNG("cd-2"),
				"Artist/Album/cover.jpg":            smallPNG("album-root"),
			})
			scan()

			al := firstAlbum()
			expectDiscImage(al, 1, "disc-1")
			expectDiscImage(al, 2, "cd-2")
		})
	})

	When("discsubtitle keyword matches an image whose stem equals the disc's subtitle", func() {
		// Artist/
		// └── Album/
		//     ├── 01 - Track.mp3       (discsubtitle="Bonus Tracks")
		//     └── Bonus Tracks.jpg     ← matched by "discsubtitle" keyword
		It("selects the subtitle-named image", func() {
			conf.Server.DiscArtPriority = "discsubtitle"
			setLayout(fstest.MapFS{
				"Artist/Album/01 - Track.mp3":   trackFile(1, "T1", map[string]any{"disc": "1", "discsubtitle": "Bonus Tracks"}),
				"Artist/Album/Bonus Tracks.jpg": smallPNG("bonus-tracks"),
			})
			scan()
			expectDiscImage(firstAlbum(), 1, "bonus-tracks")
		})
	})

	// Reproduces https://github.com/navidrome/navidrome/issues/5456
	// Deeply nested layout matching the reporter's actual structure.
	When("a deeply nested multi-disc album has cover.jpg and per-disc folder.jpg", func() {
		// Genre/Artist/Album/                 ← album root with cover.jpg
		// ├── cover.jpg                       ← album-level cover
		// ├── Disc 01 (Subtitle)/
		// │   ├── 01 - Track.mp3
		// │   └── folder.jpg                  ← disc 1 art
		// ├── Disc 02 (Subtitle)/
		// │   ├── 01 - Track.mp3
		// │   └── folder.jpg
		// └── ... (12 discs)
		It("uses album-root cover.jpg for album art and per-disc folder.jpg for each disc", func() {
			conf.Server.DiscArtPriority = defaultDiscPriority
			conf.Server.CoverArtPriority = defaultCoverPriority
			discNames := []string{
				"Disc 01 (Birth of the Dead - The Studio Sides)",
				"Disc 02 (Birth of the Dead - The Live Sides)",
				"Disc 03 (The Grateful Dead)",
				"Disc 04 (Anthem of the Sun)",
				"Disc 05 (Aoxomoxoa)",
				"Disc 06 (Live; Dead)",
				"Disc 07 (Workingman's Dead)",
				"Disc 08 (American Beauty)",
				"Disc 09 (Grateful Dead)",
				"Disc 10 (Europe '72)",
				"Disc 11 (Europe '72)",
				"Disc 12 (History of the Grateful Dead, Volume One (Bear's Choice))",
			}
			layout := fstest.MapFS{
				"Pop; Rock/Grateful Dead/(2001) The Golden Road/cover.jpg": smallPNG("album-root-cover"),
			}
			for i, name := range discNames {
				discNum := i + 1
				prefix := fmt.Sprintf("Pop; Rock/Grateful Dead/(2001) The Golden Road/%s/", name)
				layout[prefix+"01 - Track.mp3"] = trackFile(1, fmt.Sprintf("T%d", discNum), map[string]any{"disc": fmt.Sprintf("%d", discNum)})
				layout[prefix+"folder.jpg"] = smallPNG(fmt.Sprintf("disc-%02d-folder", discNum))
			}
			setLayout(layout)
			scan()

			al := firstAlbum()
			expectAlbumFolderCover(al, "(2001) The Golden Road/cover.jpg")
			for i := range discNames {
				discNum := i + 1
				expectDiscImage(al, discNum, fmt.Sprintf("disc-%02d-folder", discNum))
			}
		})
	})

	// https://github.com/navidrome/navidrome/issues/5456
	// Top-level album variant — album folder at library root (Path=".").
	When("a top-level multi-disc album has cover.jpg and per-disc folder.jpg", func() {
		// Album/                       (top-level, Path=".")
		// ├── cover.jpg                ← album-level cover
		// ├── Disc 01/
		// │   ├── 01 - Track.mp3
		// │   └── folder.jpg           ← disc 1 art
		// ├── Disc 02/
		// │   ├── 01 - Track.mp3
		// │   └── folder.jpg
		// └── Disc 03/
		//     ├── 01 - Track.mp3
		//     └── folder.jpg
		It("uses album-root cover.jpg for album art and per-disc folder.jpg for each disc", func() {
			conf.Server.DiscArtPriority = defaultDiscPriority
			conf.Server.CoverArtPriority = defaultCoverPriority
			layout := fstest.MapFS{
				"Album/cover.jpg": smallPNG("album-root-cover"),
			}
			for i := 1; i <= 3; i++ {
				prefix := fmt.Sprintf("Album/Disc %02d/", i)
				layout[prefix+"01 - Track.mp3"] = trackFile(1, fmt.Sprintf("T%d", i), map[string]any{"disc": fmt.Sprintf("%d", i)})
				layout[prefix+"folder.jpg"] = smallPNG(fmt.Sprintf("disc-%02d-folder", i))
			}
			setLayout(layout)
			scan()

			al := firstAlbum()
			expectAlbumFolderCover(al, "Album/cover.jpg")
			for i := 1; i <= 3; i++ {
				expectDiscImage(al, i, fmt.Sprintf("disc-%02d-folder", i))
			}
		})
	})

	When("discsubtitle is set but no image filename matches the subtitle", func() {
		// Artist/
		// └── Album/
		//     ├── 01 - Track.mp3       (discsubtitle="Bonus Tracks")
		//     └── cover.jpg            ← wins (discsubtitle has no match, falls through)
		It("falls through to the next priority entry", func() {
			conf.Server.DiscArtPriority = "discsubtitle, cover.*"
			setLayout(fstest.MapFS{
				"Artist/Album/01 - Track.mp3": trackFile(1, "T1", map[string]any{"disc": "1", "discsubtitle": "Bonus Tracks"}),
				"Artist/Album/cover.jpg":      smallPNG("cover"),
			})
			scan()
			expectDiscImage(firstAlbum(), 1, "cover")
		})
	})
})