package persistence

import (
	"cmp"
	"context"
	"encoding/json"
	"fmt"
	"slices"
	"strings"
	"time"

	. "github.com/Masterminds/squirrel"
	"github.com/deluan/rest"
	"github.com/navidrome/navidrome/conf"
	"github.com/navidrome/navidrome/log"
	"github.com/navidrome/navidrome/model"
	"github.com/navidrome/navidrome/utils"
	. "github.com/navidrome/navidrome/utils/gg"
	"github.com/navidrome/navidrome/utils/slice"
	"github.com/pocketbase/dbx"
)

type artistRepository struct {
	sqlRepository
	indexGroups utils.IndexGroups
}

type dbArtist struct {
	*model.Artist  `structs:",flatten"`
	SimilarArtists string `structs:"-" json:"-"`
	Stats          string `structs:"-" json:"-"`
}

type dbSimilarArtist struct {
	ID   string `json:"id,omitempty"`
	Name string `json:"name,omitempty"`
}

func (a *dbArtist) PostScan() error {
	var stats map[string]map[string]int64
	if err := json.Unmarshal([]byte(a.Stats), &stats); err != nil {
		return fmt.Errorf("parsing artist stats from db: %w", err)
	}
	a.Artist.Stats = make(map[model.Role]model.ArtistStats)
	for key, c := range stats {
		if key == "total" {
			a.Artist.Size = c["s"]
			a.Artist.SongCount = int(c["m"])
			a.Artist.AlbumCount = int(c["a"])
		}
		role := model.RoleFromString(key)
		if role == model.RoleInvalid {
			continue
		}
		a.Artist.Stats[role] = model.ArtistStats{
			SongCount:  int(c["m"]),
			AlbumCount: int(c["a"]),
			Size:       c["s"],
		}
	}
	a.Artist.SimilarArtists = nil
	if a.SimilarArtists == "" {
		return nil
	}
	var sa []dbSimilarArtist
	if err := json.Unmarshal([]byte(a.SimilarArtists), &sa); err != nil {
		return fmt.Errorf("parsing similar artists from db: %w", err)
	}
	for _, s := range sa {
		a.Artist.SimilarArtists = append(a.Artist.SimilarArtists, model.Artist{
			ID:   s.ID,
			Name: s.Name,
		})
	}
	return nil
}

func (a *dbArtist) PostMapArgs(m map[string]any) error {
	sa := make([]dbSimilarArtist, 0)
	for _, s := range a.Artist.SimilarArtists {
		sa = append(sa, dbSimilarArtist{ID: s.ID, Name: s.Name})
	}
	similarArtists, _ := json.Marshal(sa)
	m["similar_artists"] = string(similarArtists)
	m["full_text"] = formatFullText(a.Name, a.SortArtistName)

	// Do not override the sort_artist_name and mbz_artist_id fields if they are empty
	// TODO: Better way to handle this?
	if v, ok := m["sort_artist_name"]; !ok || v.(string) == "" {
		delete(m, "sort_artist_name")
	}
	if v, ok := m["mbz_artist_id"]; !ok || v.(string) == "" {
		delete(m, "mbz_artist_id")
	}
	return nil
}

type dbArtists []dbArtist

func (dba dbArtists) toModels() model.Artists {
	res := make(model.Artists, len(dba))
	for i := range dba {
		res[i] = *dba[i].Artist
	}
	return res
}

func NewArtistRepository(ctx context.Context, db dbx.Builder) model.ArtistRepository {
	r := &artistRepository{}
	r.ctx = ctx
	r.db = db
	r.indexGroups = utils.ParseIndexGroups(conf.Server.IndexGroups)
	r.tableName = "artist" // To be used by the idFilter below
	r.registerModel(&model.Artist{}, map[string]filterFunc{
		"id":      idFilter(r.tableName),
		"name":    fullTextFilter(r.tableName),
		"starred": booleanFilter,
		"role":    roleFilter,
		"missing": booleanFilter,
	})
	r.setSortMappings(map[string]string{
		"name":        "order_artist_name",
		"starred_at":  "starred, starred_at",
		"song_count":  "stats->>'total'->>'m'",
		"album_count": "stats->>'total'->>'a'",
		"size":        "stats->>'total'->>'s'",
	})
	return r
}

func roleFilter(_ string, role any) Sqlizer {
	return NotEq{fmt.Sprintf("stats ->> '$.%v'", role): nil}
}

func (r *artistRepository) selectArtist(options ...model.QueryOptions) SelectBuilder {
	query := r.newSelect(options...).Columns("artist.*")
	query = r.withAnnotation(query, "artist.id")
	return query
}

func (r *artistRepository) CountAll(options ...model.QueryOptions) (int64, error) {
	query := r.newSelect()
	query = r.withAnnotation(query, "artist.id")
	return r.count(query, options...)
}

func (r *artistRepository) Exists(id string) (bool, error) {
	return r.exists(Eq{"artist.id": id})
}

func (r *artistRepository) Put(a *model.Artist, colsToUpdate ...string) error {
	dba := &dbArtist{Artist: a}
	dba.CreatedAt = P(time.Now())
	dba.UpdatedAt = dba.CreatedAt
	_, err := r.put(dba.ID, dba, colsToUpdate...)
	return err
}

func (r *artistRepository) UpdateExternalInfo(a *model.Artist) error {
	dba := &dbArtist{Artist: a}
	_, err := r.put(a.ID, dba,
		"biography", "small_image_url", "medium_image_url", "large_image_url",
		"similar_artists", "external_url", "external_info_updated_at")
	return err
}

func (r *artistRepository) Get(id string) (*model.Artist, error) {
	sel := r.selectArtist().Where(Eq{"artist.id": id})
	var dba dbArtists
	if err := r.queryAll(sel, &dba); err != nil {
		return nil, err
	}
	if len(dba) == 0 {
		return nil, model.ErrNotFound
	}
	res := dba.toModels()
	return &res[0], nil
}

func (r *artistRepository) GetAll(options ...model.QueryOptions) (model.Artists, error) {
	sel := r.selectArtist(options...)
	var dba dbArtists
	err := r.queryAll(sel, &dba)
	if err != nil {
		return nil, err
	}
	res := dba.toModels()
	return res, err
}

func (r *artistRepository) getIndexKey(a model.Artist) string {
	source := a.OrderArtistName
	if conf.Server.PreferSortTags {
		source = cmp.Or(a.SortArtistName, a.OrderArtistName)
	}
	name := strings.ToLower(source)
	for k, v := range r.indexGroups {
		if strings.HasPrefix(name, strings.ToLower(k)) {
			return v
		}
	}
	return "#"
}

// TODO Cache the index (recalculate when there are changes to the DB)
func (r *artistRepository) GetIndex(includeMissing bool, roles ...model.Role) (model.ArtistIndexes, error) {
	options := model.QueryOptions{Sort: "name"}
	if len(roles) > 0 {
		roleFilters := slice.Map(roles, func(r model.Role) Sqlizer {
			return roleFilter("role", r)
		})
		options.Filters = And(roleFilters)
	}
	if !includeMissing {
		if options.Filters == nil {
			options.Filters = Eq{"artist.missing": false}
		} else {
			options.Filters = And{options.Filters, Eq{"artist.missing": false}}
		}
	}
	artists, err := r.GetAll(options)
	if err != nil {
		return nil, err
	}
	var result model.ArtistIndexes
	for k, v := range slice.Group(artists, r.getIndexKey) {
		result = append(result, model.ArtistIndex{ID: k, Artists: v})
	}
	slices.SortFunc(result, func(a, b model.ArtistIndex) int {
		return cmp.Compare(a.ID, b.ID)
	})
	return result, nil
}

func (r *artistRepository) purgeEmpty() error {
	del := Delete(r.tableName).Where("id not in (select artist_id from album_artists)")
	c, err := r.executeSQL(del)
	if err != nil {
		return fmt.Errorf("purging empty artists: %w", err)
	}
	if c > 0 {
		log.Debug(r.ctx, "Purged empty artists", "totalDeleted", c)
	}
	return nil
}

// markMissing sets the Missing flag based on album data.
func (r *artistRepository) markMissing() (int64, error) {
	q := Expr(`
                update artist
                set missing = not exists (
                        select 1 from album_artists aa
                        join album a on aa.album_id = a.id
                        where aa.artist_id = artist.id and a.missing = false
                )
        `)
	c, err := r.executeSQL(q)
	if err != nil {
		return 0, fmt.Errorf("marking missing artists: %w", err)
	}
	if c > 0 {
		log.Debug(r.ctx, "Marked missing artists", "totalUpdated", c)
	}
	return c, nil
}

// RefreshPlayCounts updates the play count and last play date annotations for all artists, based
// on the media files associated with them.
func (r *artistRepository) RefreshPlayCounts() (int64, error) {
	query := Expr(`
with play_counts as (
    select user_id, atom as artist_id, sum(play_count) as total_play_count, max(play_date) as last_play_date
    from media_file
    join annotation on item_id = media_file.id
    left join json_tree(participants, '$.artist') as jt
    where atom is not null and key = 'id'
    group by user_id, atom
)
insert into annotation (user_id, item_id, item_type, play_count, play_date)
select user_id, artist_id, 'artist', total_play_count, last_play_date
from play_counts
where total_play_count > 0
on conflict (user_id, item_id, item_type) do update
    set play_count = excluded.play_count,
        play_date  = excluded.play_date;
`)
	return r.executeSQL(query)
}

// RefreshStats updates the stats field for artists whose associated media files were updated after the oldest recorded library scan time.
// It processes artists in batches to handle potentially large updates.
func (r *artistRepository) RefreshStats() (int64, error) {
	touchedArtistsQuerySQL := `
        SELECT DISTINCT mfa.artist_id
        FROM media_file_artists mfa
        JOIN media_file mf ON mfa.media_file_id = mf.id
        WHERE mf.updated_at > (SELECT last_scan_at FROM library ORDER BY last_scan_at ASC LIMIT 1)
        `

	var allTouchedArtistIDs []string
	if err := r.db.NewQuery(touchedArtistsQuerySQL).Column(&allTouchedArtistIDs); err != nil {
		return 0, fmt.Errorf("fetching touched artist IDs: %w", err)
	}

	if len(allTouchedArtistIDs) == 0 {
		log.Debug(r.ctx, "RefreshStats: No artists to update.")
		return 0, nil
	}
	log.Debug(r.ctx, "RefreshStats: Found artists to update.", "count", len(allTouchedArtistIDs))

	// Template for the batch update with placeholder markers that we'll replace
	batchUpdateStatsSQL := `
    WITH artist_role_counters AS (
        SELECT jt.atom AS artist_id,
               substr(
                       replace(jt.path, '$.', ''),
                       1,
                       CASE WHEN instr(replace(jt.path, '$.', ''), '[') > 0
                                THEN instr(replace(jt.path, '$.', ''), '[') - 1
                            ELSE length(replace(jt.path, '$.', ''))
                           END
               ) AS role,
               count(DISTINCT mf.album_id) AS album_count,
               count(mf.id) AS count,
               sum(mf.size) AS size
        FROM media_file mf
        JOIN json_tree(mf.participants) jt ON jt.key = 'id' AND jt.atom IS NOT NULL
        WHERE jt.atom IN (ROLE_IDS_PLACEHOLDER) -- Will replace with actual placeholders
        GROUP BY jt.atom, role
    ),
    artist_total_counters AS (
        SELECT mfa.artist_id,
               'total' AS role,
               count(DISTINCT mf.album_id) AS album_count,
               count(DISTINCT mf.id) AS count,
               sum(mf.size) AS size
        FROM media_file_artists mfa
        JOIN media_file mf ON mfa.media_file_id = mf.id
        WHERE mfa.artist_id IN (TOTAL_IDS_PLACEHOLDER) -- Will replace with actual placeholders
        GROUP BY mfa.artist_id
    ),
    combined_counters AS (
        SELECT artist_id, role, album_count, count, size FROM artist_role_counters
        UNION
        SELECT artist_id, role, album_count, count, size FROM artist_total_counters
    ),
    artist_counters AS (
        SELECT artist_id AS id,
               json_group_object(
                       replace(role, '"', ''),
                       json_object('a', album_count, 'm', count, 's', size)
               ) AS counters
        FROM combined_counters
        GROUP BY artist_id
    )
    UPDATE artist
    SET stats = coalesce((SELECT counters FROM artist_counters ac WHERE ac.id = artist.id), '{}'),
       updated_at = datetime(current_timestamp, 'localtime')
    WHERE artist.id IN (UPDATE_IDS_PLACEHOLDER) AND artist.id <> '';` // Will replace with actual placeholders

	var totalRowsAffected int64 = 0
	const batchSize = 1000

	batchCounter := 0
	for artistIDBatch := range slice.CollectChunks(slices.Values(allTouchedArtistIDs), batchSize) {
		batchCounter++
		log.Trace(r.ctx, "RefreshStats: Processing batch", "batchNum", batchCounter, "batchSize", len(artistIDBatch))

		// Create placeholders for each ID in the IN clauses
		placeholders := make([]string, len(artistIDBatch))
		for i := range artistIDBatch {
			placeholders[i] = "?"
		}
		// Don't add extra parentheses, the IN clause already expects them in SQL syntax
		inClause := strings.Join(placeholders, ",")

		// Replace the placeholder markers with actual SQL placeholders
		batchSQL := strings.Replace(batchUpdateStatsSQL, "ROLE_IDS_PLACEHOLDER", inClause, 1)
		batchSQL = strings.Replace(batchSQL, "TOTAL_IDS_PLACEHOLDER", inClause, 1)
		batchSQL = strings.Replace(batchSQL, "UPDATE_IDS_PLACEHOLDER", inClause, 1)

		// Create a single parameter array with all IDs (repeated 3 times for each IN clause)
		// We need to repeat each ID 3 times (once for each IN clause)
		var args []interface{}
		for _, id := range artistIDBatch {
			args = append(args, id) // For ROLE_IDS_PLACEHOLDER
		}
		for _, id := range artistIDBatch {
			args = append(args, id) // For TOTAL_IDS_PLACEHOLDER
		}
		for _, id := range artistIDBatch {
			args = append(args, id) // For UPDATE_IDS_PLACEHOLDER
		}

		// Now use Expr with the expanded SQL and all parameters
		sqlizer := Expr(batchSQL, args...)

		rowsAffected, err := r.executeSQL(sqlizer)
		if err != nil {
			return totalRowsAffected, fmt.Errorf("executing batch update for artist stats (batch %d): %w", batchCounter, err)
		}
		totalRowsAffected += rowsAffected
	}

	log.Debug(r.ctx, "RefreshStats: Successfully updated stats.", "totalArtistsProcessed", len(allTouchedArtistIDs), "totalDBRowsAffected", totalRowsAffected)
	return totalRowsAffected, nil
}

func (r *artistRepository) Search(q string, offset int, size int, includeMissing bool) (model.Artists, error) {
	var dba dbArtists
	err := r.doSearch(r.selectArtist(), q, offset, size, includeMissing, &dba, "json_extract(stats, '$.total.m') desc", "name")
	if err != nil {
		return nil, err
	}
	return dba.toModels(), nil
}

func (r *artistRepository) Count(options ...rest.QueryOptions) (int64, error) {
	return r.CountAll(r.parseRestOptions(r.ctx, options...))
}

func (r *artistRepository) Read(id string) (interface{}, error) {
	return r.Get(id)
}

func (r *artistRepository) ReadAll(options ...rest.QueryOptions) (interface{}, error) {
	role := "total"
	if len(options) > 0 {
		if v, ok := options[0].Filters["role"].(string); ok {
			role = v
		}
	}
	r.sortMappings["song_count"] = "stats->>'" + role + "'->>'m'"
	r.sortMappings["album_count"] = "stats->>'" + role + "'->>'a'"
	r.sortMappings["size"] = "stats->>'" + role + "'->>'s'"
	return r.GetAll(r.parseRestOptions(r.ctx, options...))
}

func (r *artistRepository) EntityName() string {
	return "artist"
}

func (r *artistRepository) NewInstance() interface{} {
	return &model.Artist{}
}

var _ model.ArtistRepository = (*artistRepository)(nil)
var _ model.ResourceRepository = (*artistRepository)(nil)