package uploads

import (
	"context"
	"errors"
	"net/http"
	"os"
	"sort"
	"strconv"
	"time"

	"github.com/google/uuid"
	"pipu/api/internal/auth"
	"pipu/api/internal/musicbrainz"
	"pipu/api/internal/platform/apperr"
)

func (s *Service) lookupNextRelease(ctx context.Context) bool {
	job, err := s.store.ClaimRelease(ctx)
	if errors.Is(err, ErrNotFound) {
		return false
	}
	if err != nil {
		s.log.Error("uploads: release job", "err", err)
		return false
	}
	run, cancel := context.WithTimeout(ctx, 4*time.Minute)
	defer cancel()
	files, err := s.store.AllInReleaseGroup(run, job.ID, job.GroupKey)
	report := ReleaseReport{State: "error", Candidates: []ReleaseCandidate{}, GroupID: job.GroupKey}
	if err == nil {
		report.InputHash = releaseHash(files)
		q := job.Query
		var audio map[uuid.UUID]AudioRecognition
		if q.Audio {
			report.AudioResults, audio, q.RecordingIDs, err = s.identifyAudio(run, files)
		}
		valid := true
		if !q.Audio && q.Artist == "" && q.Album == "" && q.ReleaseID == "" {
			q, valid = batchReleaseQuery(files)
		}
		if err != nil {
			report.State = "error"
		} else if q.Audio && len(q.RecordingIDs) == 0 {
			report.State = "not_found"
		} else if !q.Audio && (!valid || q.ReleaseID == "" && (q.Artist == "" || q.Album == "")) {
			report.State = "needs_input"
		} else {
			var releases []musicbrainz.Release
			releases, err = s.catalogue.Search(run, q)
			if err == nil {
				report.State = "not_found"
				for _, release := range releases {
					candidate := matchReleaseWithAudio(files, release, audio)
					candidate.Existing, err = s.store.ExistingReleaseTracks(run, candidate.Missing)
					if err != nil {
						break
					}
					report.Candidates = append(report.Candidates, candidate)
				}
				if len(report.Candidates) > 0 {
					report.State = "ready"
				}
				sort.SliceStable(report.Candidates, func(i, j int) bool {
					a, b := report.Candidates[i], report.Candidates[j]
					if a.Complete != b.Complete {
						return a.Complete
					}
					if a.Matched != b.Matched {
						return a.Matched > b.Matched
					}
					return len(a.Unmatched) < len(b.Unmatched)
				})
			}
		}
	}
	if err != nil {
		report.State = "error"
		report.Candidates = []ReleaseCandidate{}
		s.log.Warn("uploads: release lookup", "batch_id", job.ID, "err", err)
	}
	if err = s.store.SaveRelease(ctx, job, report); err != nil {
		s.log.Error("uploads: save release lookup", "err", err)
	}
	return true
}
func (s *Service) GetReleaseReport(ctx context.Context, id uuid.UUID, scope ...string) (ReleaseReport, error) {
	if _, err := principal(ctx, auth.PermReviewUploads); err != nil {
		return ReleaseReport{}, err
	}
	files, err := s.store.AllInBatch(ctx, id)
	if err != nil {
		return ReleaseReport{}, notFound(err)
	}
	files, groups, key, err := s.releaseScope(ctx, id, firstGroup(scope))
	if err != nil {
		return ReleaseReport{}, err
	}
	if s.catalogue == nil {
		return ReleaseReport{State: "disabled", Candidates: []ReleaseCandidate{}, GroupID: key, Groups: groups}, nil
	}
	if len(groups) > 1 && key == "" {
		return ReleaseReport{State: "needs_input", Candidates: []ReleaseCandidate{}, Groups: groups, AudioAvailable: s.identifier != nil}, nil
	}
	report, err := s.store.ReleaseReport(ctx, id, key)
	if err != nil {
		return report, err
	}
	if report.InputHash != "" && report.InputHash != releaseHash(files) && report.State != "queued" && report.State != "searching" {
		if err = s.store.QueueRelease(ctx, id, musicbrainz.Query{GroupID: key}); err != nil {
			return report, err
		}
		report = ReleaseReport{State: "queued", Candidates: []ReleaseCandidate{}, GroupID: key}
	}
	report.AudioAvailable = s.identifier != nil
	report.Groups = groups
	return report, nil
}
func (s *Service) SearchReleases(ctx context.Context, id uuid.UUID, q musicbrainz.Query) (ReleaseReport, error) {
	if _, err := principal(ctx, auth.PermReviewUploads); err != nil {
		return ReleaseReport{}, err
	}
	if s.catalogue == nil {
		return ReleaseReport{}, apperr.Conflict("uploads.metadata_disabled", "external metadata is disabled")
	}
	if q.Audio && s.identifier == nil {
		return ReleaseReport{}, apperr.Conflict("uploads.audio_disabled", "AcoustID application key is not configured")
	}
	files, groups, key, err := s.releaseScope(ctx, id, q.GroupID)
	if err != nil {
		return ReleaseReport{}, notFound(err)
	}
	if key == "" {
		return ReleaseReport{}, apperr.Conflict("uploads.release_group_required", "choose a release group")
	}
	q.GroupID = key
	editable := false
	for _, f := range files {
		editable = editable || f.Status == StatusPendingReview || f.Status == StatusImportFailed
	}
	if !editable {
		return ReleaseReport{}, notFound(ErrWrongStatus)
	}
	if q.Audio {
		count := 0
		for _, f := range releaseFiles(files) {
			if f.Status == StatusPendingReview || f.Status == StatusImportFailed {
				count++
			}
		}
		if count > maxAudioFiles {
			return ReleaseReport{}, apperr.Validation("audio", "uploads.audio_batch_limit", "at most 50 editable tracks per audio lookup", nil)
		}
		q = musicbrainz.Query{Audio: true, GroupID: key}
	}
	if len(q.Artist) > 500 || len(q.Album) > 500 {
		return ReleaseReport{}, apperr.Validation("query", "common.bad_request", "query too long", nil)
	}
	if q.ReleaseID != "" {
		if _, err = uuid.Parse(q.ReleaseID); err != nil {
			return ReleaseReport{}, apperr.Validation("release_id", "common.bad_request", "invalid release ID", nil)
		}
	}
	if err = s.store.QueueRelease(ctx, id, q); err != nil {
		return ReleaseReport{}, err
	}
	return ReleaseReport{State: "queued", Candidates: []ReleaseCandidate{}, AudioAvailable: s.identifier != nil, GroupID: key, Groups: groups}, nil
}
func (s *Service) releaseCandidate(ctx context.Context, batch uuid.UUID, release string, scope ...string) (ReleaseCandidate, []File, ReleaseReport, error) {
	if _, err := principal(ctx, auth.PermReviewUploads); err != nil {
		return ReleaseCandidate{}, nil, ReleaseReport{}, err
	}
	files, groups, key, err := s.releaseScope(ctx, batch, firstGroup(scope))
	if err != nil {
		return ReleaseCandidate{}, nil, ReleaseReport{}, notFound(err)
	}
	if len(groups) > 1 && key == "" {
		return ReleaseCandidate{}, nil, ReleaseReport{}, apperr.Conflict("uploads.release_group_required", "choose a release group")
	}
	report, err := s.store.ReleaseReport(ctx, batch, key)
	if err != nil {
		return ReleaseCandidate{}, files, report, err
	}
	report.Groups = groups
	if report.State != "ready" || report.InputHash != releaseHash(files) {
		return ReleaseCandidate{}, files, report, apperr.Conflict("uploads.release_stale", "metadata changed; repeat release lookup")
	}
	for _, candidate := range report.Candidates {
		if candidate.Release.ID == release {
			return candidate, files, report, nil
		}
	}
	return ReleaseCandidate{}, files, report, apperr.NotFound("uploads.release_not_found", "release is not in this batch's candidates")
}
func (s *Service) ReleaseCover(ctx context.Context, batch uuid.UUID, release string, scope ...string) (musicbrainz.Cover, error) {
	c, _, _, err := s.releaseCandidate(ctx, batch, release, scope...)
	if err != nil {
		return musicbrainz.Cover{}, err
	}
	if s.catalogue == nil {
		return musicbrainz.Cover{}, apperr.Conflict("uploads.metadata_disabled", "external metadata is disabled")
	}
	cover, err := s.catalogue.Cover(ctx, c.Release)
	if errors.Is(err, musicbrainz.ErrNotFound) {
		return cover, apperr.NotFound("uploads.release_cover_missing", "release has no cover")
	}
	if err != nil {
		return cover, apperr.New(http.StatusServiceUnavailable, "uploads.metadata_unavailable", "cover provider is unavailable")
	}
	return cover, err
}

type releaseChange struct {
	File      File
	Meta      Meta
	Placement placement
	Tags      map[string]string
}

func (s *Service) ApplyRelease(ctx context.Context, batch uuid.UUID, release string, metadata, cover bool, scope ...string) (ReleaseReport, error) {
	candidate, files, report, err := s.releaseCandidate(ctx, batch, release, scope...)
	if err != nil {
		return report, err
	}
	if !metadata && !cover {
		return report, apperr.Validation("apply_metadata", "common.bad_request", "choose metadata or cover", nil)
	}
	var coverPath *string
	if cover {
		image, err := s.ReleaseCover(ctx, batch, release, report.GroupID)
		if err != nil {
			return report, err
		}
		coverPath, err = s.createCover(image.Data)
		if err != nil {
			return report, err
		}
	}
	committed := false
	defer func() {
		if !committed && coverPath != nil {
			_ = os.Remove(s.stagingAbs(*coverPath))
		}
	}()
	changes := []releaseChange{}
	byID := map[uuid.UUID]int{}
	for i, f := range files {
		byID[f.ID] = i
	}
	for _, match := range candidate.Matches {
		i := byID[match.FileID]
		f := files[i]
		if !metadata || f.Meta == nil || f.Status != StatusPendingReview && f.Status != StatusImportFailed {
			continue
		}
		t := candidate.Release.Tracks[match.TrackIndex]
		m := *f.Meta
		m.Artist, m.AlbumArtist, m.Album, m.Title = t.Artist, candidate.Release.Artist, candidate.Release.Title, t.Title
		m.Disc, m.Track = &t.Disc, &t.Position
		if len(candidate.Release.Date) >= 4 {
			if y, e := strconv.Atoi(candidate.Release.Date[:4]); e == nil {
				m.Year = &y
			}
		}
		m = normalizeMeta(m)
		tags := map[string]string{}
		for k, v := range f.Tags {
			tags[k] = v
		}
		tags["musicbrainz_albumid"], tags["musicbrainz_releasegroupid"], tags["musicbrainz_trackid"] = candidate.Release.ID, candidate.Release.GroupID, t.RecordingID
		changes = append(changes, releaseChange{f, m, s.plan(ctx, f, m, f.TargetSourceID), tags})
		files[i].Meta, files[i].Tags = &m, tags
	}
	if metadata && len(changes) == 0 {
		return report, apperr.Conflict(CodeWrongStatus, "no matched editable tracks")
	}
	report.SelectedRelease = &release
	next := report
	next.InputHash = releaseHash(files)
	reviewer, _ := principal(ctx, auth.PermReviewUploads)
	if err = s.store.ApplyRelease(ctx, batch, report.InputHash, changes, coverPath, next, reviewer.UserID); err != nil {
		return report, notFound(err)
	}
	committed = true
	next.AudioAvailable = s.identifier != nil
	for i, g := range next.Groups {
		if g.ID == next.GroupID {
			if cover {
				next.Groups[i].HasCover = true
			}
			if metadata {
				next.Groups[i].Artist = candidate.Release.Artist
				next.Groups[i].Album = candidate.Release.Title
			}
		}
	}
	return next, nil
}