package core

import (
	"context"
	"errors"
	"sync"
	"time"

	"github.com/navidrome/navidrome/model"
	"github.com/navidrome/navidrome/model/request"
	"github.com/navidrome/navidrome/tests"
	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"
	"github.com/sirupsen/logrus"
)

var _ = Describe("Maintenance", func() {
	var ds *tests.MockDataStore
	var mfRepo *extendedMediaFileRepo
	var service Maintenance
	var ctx context.Context

	BeforeEach(func() {
		ctx = context.Background()
		ctx = request.WithUser(ctx, model.User{ID: "user1", IsAdmin: true})

		ds = createTestDataStore()
		mfRepo = ds.MockedMediaFile.(*extendedMediaFileRepo)
		service = NewMaintenance(ds)
	})

	Describe("DeleteMissingFiles", func() {
		Context("with specific IDs", func() {
			It("deletes specific missing files and runs GC", func() {
				// Setup: mock missing files with album IDs
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "album1", Missing: true},
					{ID: "mf2", AlbumID: "album2", Missing: true},
				})

				err := service.DeleteMissingFiles(ctx, []string{"mf1", "mf2"})

				Expect(err).ToNot(HaveOccurred())
				Expect(mfRepo.deleteMissingCalled).To(BeTrue())
				Expect(mfRepo.deletedIDs).To(Equal([]string{"mf1", "mf2"}))
				Expect(ds.GCCalled).To(BeTrue(), "GC should be called after deletion")
			})

			It("triggers artist stats refresh and album refresh after deletion", func() {
				artistRepo := ds.MockedArtist.(*extendedArtistRepo)
				// Setup: mock missing files with albums
				albumRepo := ds.MockedAlbum.(*extendedAlbumRepo)
				albumRepo.SetData(model.Albums{
					{ID: "album1", Name: "Test Album", SongCount: 5},
				})
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "album1", Missing: true},
					{ID: "mf2", AlbumID: "album1", Missing: false, Size: 1000, Duration: 180},
					{ID: "mf3", AlbumID: "album1", Missing: false, Size: 2000, Duration: 200},
				})

				err := service.DeleteMissingFiles(ctx, []string{"mf1"})

				Expect(err).ToNot(HaveOccurred())

				// Wait for background goroutines to complete
				service.(*maintenanceService).wait()

				// RefreshStats should be called
				Expect(artistRepo.IsRefreshStatsCalled()).To(BeTrue(), "Artist stats should be refreshed")

				// Album should be updated with new calculated values
				Expect(albumRepo.GetPutCallCount()).To(BeNumerically(">", 0), "Album.Put() should be called to refresh album data")
			})

			It("returns error if deletion fails", func() {
				mfRepo.deleteMissingError = errors.New("delete failed")

				err := service.DeleteMissingFiles(ctx, []string{"mf1"})

				Expect(err).To(HaveOccurred())
				Expect(err.Error()).To(ContainSubstring("delete failed"))
			})

			It("continues even if album tracking fails", func() {
				mfRepo.SetError(true)

				err := service.DeleteMissingFiles(ctx, []string{"mf1"})

				// Should not fail, just log warning
				Expect(err).ToNot(HaveOccurred())
				Expect(mfRepo.deleteMissingCalled).To(BeTrue())
			})

			It("returns error if GC fails", func() {
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "album1", Missing: true},
				})

				// Set GC to return error
				ds.GCError = errors.New("gc failed")

				err := service.DeleteMissingFiles(ctx, []string{"mf1"})

				Expect(err).To(HaveOccurred())
				Expect(err.Error()).To(ContainSubstring("gc failed"))
			})
		})

		Context("album ID extraction", func() {
			It("extracts unique album IDs from missing files", func() {
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "album1", Missing: true},
					{ID: "mf2", AlbumID: "album1", Missing: true},
					{ID: "mf3", AlbumID: "album2", Missing: true},
				})

				err := service.DeleteMissingFiles(ctx, []string{"mf1", "mf2", "mf3"})

				Expect(err).ToNot(HaveOccurred())
			})

			It("skips files without album IDs", func() {
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "", Missing: true},
					{ID: "mf2", AlbumID: "album1", Missing: true},
				})

				err := service.DeleteMissingFiles(ctx, []string{"mf1", "mf2"})

				Expect(err).ToNot(HaveOccurred())
			})
		})
	})

	Describe("DeleteAllMissingFiles", func() {
		It("deletes all missing files and runs GC", func() {
			mfRepo.SetData(model.MediaFiles{
				{ID: "mf1", AlbumID: "album1", Missing: true},
				{ID: "mf2", AlbumID: "album2", Missing: true},
				{ID: "mf3", AlbumID: "album3", Missing: true},
			})

			err := service.DeleteAllMissingFiles(ctx)

			Expect(err).ToNot(HaveOccurred())
			Expect(ds.GCCalled).To(BeTrue(), "GC should be called after deletion")
		})

		It("returns error if deletion fails", func() {
			mfRepo.SetError(true)

			err := service.DeleteAllMissingFiles(ctx)

			Expect(err).To(HaveOccurred())
		})

		It("handles empty result gracefully", func() {
			mfRepo.SetData(model.MediaFiles{})

			err := service.DeleteAllMissingFiles(ctx)

			Expect(err).ToNot(HaveOccurred())
		})
	})

	Describe("Album refresh logic", func() {
		var albumRepo *extendedAlbumRepo

		BeforeEach(func() {
			albumRepo = ds.MockedAlbum.(*extendedAlbumRepo)
		})

		Context("when album has no tracks after deletion", func() {
			It("skips the album without updating it", func() {
				// Setup album with no remaining tracks
				albumRepo.SetData(model.Albums{
					{ID: "album1", Name: "Empty Album", SongCount: 1},
				})
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "album1", Missing: true},
				})

				err := service.DeleteMissingFiles(ctx, []string{"mf1"})

				Expect(err).ToNot(HaveOccurred())

				// Wait for background goroutines to complete
				service.(*maintenanceService).wait()

				// Album should NOT be updated because it has no tracks left
				Expect(albumRepo.GetPutCallCount()).To(Equal(0), "Album with no tracks should not be updated")
			})
		})

		Context("when Put fails for one album", func() {
			It("continues processing other albums", func() {
				albumRepo.SetData(model.Albums{
					{ID: "album1", Name: "Album 1"},
					{ID: "album2", Name: "Album 2"},
				})
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "album1", Missing: true},
					{ID: "mf2", AlbumID: "album1", Missing: false, Size: 1000, Duration: 180},
					{ID: "mf3", AlbumID: "album2", Missing: true},
					{ID: "mf4", AlbumID: "album2", Missing: false, Size: 2000, Duration: 200},
				})

				// Make Put fail on first call but succeed on subsequent calls
				albumRepo.putError = errors.New("put failed")
				albumRepo.failOnce = true

				err := service.DeleteMissingFiles(ctx, []string{"mf1", "mf3"})

				// Should not fail even if one album's Put fails
				Expect(err).ToNot(HaveOccurred())

				// Wait for background goroutines to complete
				service.(*maintenanceService).wait()

				// Put should have been called multiple times
				Expect(albumRepo.GetPutCallCount()).To(BeNumerically(">", 0), "Put should be attempted")
			})
		})

		Context("when media file loading fails", func() {
			It("logs warning but continues when tracking affected albums fails", func() {
				// Set up log capturing
				hook, cleanup := tests.LogHook()
				defer cleanup()

				albumRepo.SetData(model.Albums{
					{ID: "album1", Name: "Album 1"},
				})
				mfRepo.SetData(model.MediaFiles{
					{ID: "mf1", AlbumID: "album1", Missing: true},
				})
				// Make GetAll fail when loading media files
				mfRepo.SetError(true)

				err := service.DeleteMissingFiles(ctx, []string{"mf1"})

				// Deletion should succeed despite the tracking error
				Expect(err).ToNot(HaveOccurred())
				Expect(mfRepo.deleteMissingCalled).To(BeTrue())

				// Verify the warning was logged
				Expect(hook.LastEntry()).ToNot(BeNil())
				Expect(hook.LastEntry().Level).To(Equal(logrus.WarnLevel))
				Expect(hook.LastEntry().Message).To(Equal("Error tracking affected albums for refresh"))
			})
		})
	})

	Describe("RemapMissingFile", func() {
		It("relocates the missing file's identity onto the target and runs GC", func() {
			created := time.Now().Add(-30 * 24 * time.Hour)
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", Path: "old/song.mp3", AlbumID: "album1", CreatedAt: created, Missing: true},
				{ID: "t1", Path: "new/song.mp3", AlbumID: "album1", Missing: false},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(Succeed())

			got, err := mfRepo.Get(ctx, "m1")
			Expect(err).ToNot(HaveOccurred())
			Expect(got.Path).To(Equal("new/song.mp3")) // moved to target's location
			Expect(got.Missing).To(BeFalse())
			Expect(got.CreatedAt).To(BeTemporally("==", created)) // created_at preserved
			exists, _ := mfRepo.Exists(ctx, "t1")
			Expect(exists).To(BeFalse()) // discarded row removed
			Expect(ds.GCCalled).To(BeTrue())
		})

		It("moves the target's annotations, bookmarks and playlist entries onto the surviving id", func() {
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", AlbumID: "album1", Missing: true},
				{ID: "t1", AlbumID: "album1", Missing: false},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(Succeed())

			Expect(mfRepo.ReassignReferencesCalls).To(HaveKeyWithValue("t1", "m1"))
		})

		It("reassigns album annotations when the old album is emptied", func() {
			albumRepo := ds.MockedAlbum.(*extendedAlbumRepo)
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", AlbumID: "album1", Missing: true},
				{ID: "t1", AlbumID: "album2", Missing: false},
			})

			mfRepo.SetCountAll(0)
			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(Succeed())

			Expect(albumRepo.ReassignAnnotationCalls).To(HaveKeyWithValue("album1", "album2"))
		})

		It("does not reassign album annotations when the old album is not emptied", func() {
			albumRepo := ds.MockedAlbum.(*extendedAlbumRepo)
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", AlbumID: "album1", Missing: true},
				{ID: "m2", AlbumID: "album1", Missing: false},
				{ID: "t1", AlbumID: "album2", Missing: false},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(Succeed())

			Expect(albumRepo.ReassignAnnotationCalls).To(BeEmpty())
		})

		It("does not reassign annotations when the album is unchanged", func() {
			albumRepo := ds.MockedAlbum.(*extendedAlbumRepo)
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", AlbumID: "album1", Missing: true},
				{ID: "t1", AlbumID: "album1", Missing: false},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(Succeed())

			Expect(albumRepo.ReassignAnnotationCalls).To(BeEmpty())
		})

		It("returns ErrNotFound when the missing file does not exist", func() {
			mfRepo.SetData(model.MediaFiles{{ID: "t1", Missing: false}})

			Expect(service.RemapMissingFile(ctx, "nope", "t1")).To(MatchError(model.ErrNotFound))
		})

		It("refuses to remap from a file that is not missing", func() {
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", Missing: false},
				{ID: "t1", Missing: false},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(MatchError(ErrNotMissing))
		})

		It("refuses to remap a file onto itself", func() {
			mfRepo.SetData(model.MediaFiles{{ID: "m1", Missing: true}})

			Expect(service.RemapMissingFile(ctx, "m1", "m1")).To(MatchError(ErrSameFile))
		})

		It("refuses to remap onto a target that is itself missing", func() {
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", Missing: true},
				{ID: "t1", Missing: true},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(MatchError(ErrTargetMissing))
		})

		It("refreshes artist and album stats right after the remap", func() {
			artistRepo := ds.MockedArtist.(*extendedArtistRepo)
			albumRepo := ds.MockedAlbum.(*extendedAlbumRepo)
			albumRepo.SetData(model.Albums{
				{ID: "album1", Name: "Old Album", SongCount: 2, Size: 1100, Duration: 110},
				{ID: "album2", Name: "New Album", SongCount: 1, Size: 2000, Duration: 200},
			})
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", Path: "old/1.mp3", Album: "Old Album", AlbumID: "album1", Missing: true, Size: 100, Duration: 10},
				{ID: "k1", Path: "old/2.mp3", Album: "Old Album", AlbumID: "album1", Missing: false, Size: 1000, Duration: 100},
				{ID: "t1", Path: "new/1.mp3", Album: "New Album", AlbumID: "album2", Missing: false, Size: 2000, Duration: 200},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(Succeed())

			Expect(artistRepo.IsRefreshStatsCalled()).To(BeTrue(), "Artist stats should be refreshed")

			// The old album lost the remapped track, so its stats are recalculated from the remaining one
			oldAlbum, err := albumRepo.Get(ctx, "album1")
			Expect(err).ToNot(HaveOccurred())
			Expect(oldAlbum.SongCount).To(Equal(1))
			Expect(oldAlbum.Size).To(Equal(int64(1000)))
			Expect(oldAlbum.Duration).To(BeNumerically("==", 100))

			// The target album keeps the track, now under the missing file's ID
			newAlbum, err := albumRepo.Get(ctx, "album2")
			Expect(err).ToNot(HaveOccurred())
			Expect(newAlbum.SongCount).To(Equal(1))
			Expect(newAlbum.Size).To(Equal(int64(2000)))
			Expect(newAlbum.Duration).To(BeNumerically("==", 200))
		})

		It("returns an error if GC fails", func() {
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", AlbumID: "album1", Missing: true},
				{ID: "t1", AlbumID: "album1", Missing: false},
			})
			ds.GCError = errors.New("gc failed")

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(MatchError(ContainSubstring("gc failed")))
		})

		It("preserves the target's participants on the remapped track", func() {
			participant := model.Participant{
				Artist: model.Artist{ID: "a1", Name: "Artist", OrderArtistName: "artist", MbzArtistID: "mbz-artist"},
			}
			mfRepo.SetData(model.MediaFiles{
				{ID: "m1", AlbumID: "album1", Missing: true},
				{ID: "t1", AlbumID: "album2", Missing: false, Participants: model.Participants{
					model.RoleArtist: model.ParticipantList{participant},
				}},
			})

			Expect(service.RemapMissingFile(ctx, "m1", "t1")).To(Succeed())

			// The surviving row is the missing file's ID, holding the target's data
			got, err := mfRepo.GetWithParticipants(ctx, "m1")
			Expect(err).ToNot(HaveOccurred())
			Expect(got.Participants).To(HaveKeyWithValue(model.RoleArtist, model.ParticipantList{participant}))
		})
	})
})

// Test helper to create a mock DataStore with controllable behavior
func createTestDataStore() *tests.MockDataStore {
	ds := &tests.MockDataStore{}

	// Create extended album repo with Put tracking
	albumRepo := &extendedAlbumRepo{
		MockAlbumRepo: tests.CreateMockAlbumRepo(),
	}
	ds.MockedAlbum = albumRepo

	// Create extended artist repo with RefreshStats tracking
	artistRepo := &extendedArtistRepo{
		MockArtistRepo: tests.CreateMockArtistRepo(),
	}
	ds.MockedArtist = artistRepo

	// Create extended media file repo with DeleteMissing support
	mfRepo := &extendedMediaFileRepo{
		MockMediaFileRepo: tests.CreateMockMediaFileRepo(),
	}
	ds.MockedMediaFile = mfRepo

	return ds
}

// Extension of MockMediaFileRepo to add DeleteMissing method
type extendedMediaFileRepo struct {
	*tests.MockMediaFileRepo
	deleteMissingCalled bool
	deletedIDs          []string
	deleteMissingError  error
}

func (m *extendedMediaFileRepo) DeleteMissing(ctx context.Context, ids []string) error {
	m.deleteMissingCalled = true
	m.deletedIDs = ids
	if m.deleteMissingError != nil {
		return m.deleteMissingError
	}
	// Actually delete from the mock data
	for _, id := range ids {
		delete(m.Data, id)
	}
	return nil
}

// Extension of MockAlbumRepo to track Put calls
type extendedAlbumRepo struct {
	*tests.MockAlbumRepo
	mu           sync.RWMutex
	putCallCount int
	lastPutData  *model.Album
	putError     error
	failOnce     bool
}

func (m *extendedAlbumRepo) Put(ctx context.Context, album *model.Album) error {
	m.mu.Lock()
	m.putCallCount++
	m.lastPutData = album

	// Handle failOnce behavior
	var err error
	if m.putError != nil {
		if m.failOnce {
			err = m.putError
			m.putError = nil // Clear error after first failure
			m.mu.Unlock()
			return err
		}
		err = m.putError
		m.mu.Unlock()
		return err
	}
	m.mu.Unlock()

	return m.MockAlbumRepo.Put(ctx, album)
}

func (m *extendedAlbumRepo) GetPutCallCount() int {
	m.mu.RLock()
	defer m.mu.RUnlock()
	return m.putCallCount
}

// Extension of MockArtistRepo to track RefreshStats calls
type extendedArtistRepo struct {
	*tests.MockArtistRepo
	mu                 sync.RWMutex
	refreshStatsCalled bool
	refreshStatsError  error
}

func (m *extendedArtistRepo) RefreshStats(ctx context.Context, allArtists bool) (int64, error) {
	m.mu.Lock()
	m.refreshStatsCalled = true
	err := m.refreshStatsError
	m.mu.Unlock()

	if err != nil {
		return 0, err
	}
	return m.MockArtistRepo.RefreshStats(ctx, allArtists)
}

func (m *extendedArtistRepo) IsRefreshStatsCalled() bool {
	m.mu.RLock()
	defer m.mu.RUnlock()
	return m.refreshStatsCalled
}