package database

import (
	"database/sql"
	"fmt"
	"strings"
	"time"

	_ "github.com/mattn/go-sqlite3"
)

// joinSecondaryTypes renders a slice of secondary types as a comma-separated
// string for storage in the secondary_types TEXT column (empty when none).
func joinSecondaryTypes(types []string) string {
	return strings.Join(types, ",")
}

// splitSecondaryTypes parses the comma-separated secondary_types column back
// into a slice. A NULL/empty column yields an empty slice.
func splitSecondaryTypes(s string) []string {
	if s == "" {
		return nil
	}
	parts := strings.Split(s, ",")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		if p != "" {
			out = append(out, p)
		}
	}
	return out
}

// GetExternalRelease retrieves an external_release row by RGID.
func GetExternalRelease(db *DB, rgid string) (*ExternalRelease, error) {
	var r ExternalRelease
	var cachedAt sql.NullTime
	var secondaryTypes sql.NullString
	err := db.Conn().QueryRow(
		"SELECT rgid, artist_id, title, type, release_date, is_ignored, cached_at, secondary_types FROM external_releases WHERE rgid = ?",
		rgid,
	).Scan(&r.RGID, &r.ArtistID, &r.Title, &r.Type, &r.ReleaseDate, &r.IsIgnored, &cachedAt, &secondaryTypes)
	if err != nil {
		return nil, fmt.Errorf("get external release: %w", err)
	}
	if cachedAt.Valid {
		r.CachedAt = cachedAt.Time
	}
	if secondaryTypes.Valid {
		r.SecondaryTypes = splitSecondaryTypes(secondaryTypes.String)
	}
	return &r, nil
}

// SaveExternalRelease inserts or replaces an external_release row.
func SaveExternalRelease(db *DB, release *ExternalRelease) error {
	var cachedAt interface{}
	if !release.CachedAt.IsZero() {
		cachedAt = release.CachedAt
	}
	_, err := db.Conn().Exec(
		"INSERT OR REPLACE INTO external_releases (rgid, artist_id, title, type, release_date, is_ignored, cached_at, secondary_types) VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
		release.RGID, release.ArtistID, release.Title, release.Type, release.ReleaseDate, release.IsIgnored, cachedAt, joinSecondaryTypes(release.SecondaryTypes),
	)
	if err != nil {
		return fmt.Errorf("save external release: %w", err)
	}
	return nil
}

// GetExternalReleasesByArtist returns all external_release rows for a given artist_id.
func GetExternalReleasesByArtist(db *DB, artistID string) ([]ExternalRelease, error) {
	rows, err := db.Conn().Query(
		"SELECT rgid, artist_id, title, type, release_date, is_ignored, cached_at, secondary_types FROM external_releases WHERE artist_id = ?",
		artistID,
	)
	if err != nil {
		return nil, fmt.Errorf("query external releases by artist: %w", err)
	}
	defer rows.Close()

	var results []ExternalRelease
	for rows.Next() {
		var r ExternalRelease
		var cachedAt sql.NullTime
		var secondaryTypes sql.NullString
		if err := rows.Scan(&r.RGID, &r.ArtistID, &r.Title, &r.Type, &r.ReleaseDate, &r.IsIgnored, &cachedAt, &secondaryTypes); err != nil {
			return nil, fmt.Errorf("scan external release: %w", err)
		}
		if cachedAt.Valid {
			r.CachedAt = cachedAt.Time
		}
		if secondaryTypes.Valid {
			r.SecondaryTypes = splitSecondaryTypes(secondaryTypes.String)
		}
		results = append(results, r)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("iterate external releases: %w", err)
	}
	return results, nil
}

// GetIgnoredReleases returns all external_release rows where is_ignored = 1.
func GetIgnoredReleases(db *DB) ([]ExternalRelease, error) {
	rows, err := db.Conn().Query(
		"SELECT rgid, artist_id, title, type, release_date, is_ignored, cached_at, secondary_types FROM external_releases WHERE is_ignored = 1",
	)
	if err != nil {
		return nil, fmt.Errorf("query ignored releases: %w", err)
	}
	defer rows.Close()

	var results []ExternalRelease
	for rows.Next() {
		var r ExternalRelease
		var cachedAt sql.NullTime
		var secondaryTypes sql.NullString
		if err := rows.Scan(&r.RGID, &r.ArtistID, &r.Title, &r.Type, &r.ReleaseDate, &r.IsIgnored, &cachedAt, &secondaryTypes); err != nil {
			return nil, fmt.Errorf("scan ignored release: %w", err)
		}
		if cachedAt.Valid {
			r.CachedAt = cachedAt.Time
		}
		if secondaryTypes.Valid {
			r.SecondaryTypes = splitSecondaryTypes(secondaryTypes.String)
		}
		results = append(results, r)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("iterate ignored releases: %w", err)
	}
	return results, nil
}

// SetReleaseIgnored updates the is_ignored flag for a given RGID.
func SetReleaseIgnored(db *DB, rgid string, ignored bool) error {
	result, err := db.Conn().Exec(
		"UPDATE external_releases SET is_ignored = ? WHERE rgid = ?",
		ignored, rgid,
	)
	if err != nil {
		return fmt.Errorf("set release ignored: %w", err)
	}

	rowsAffected, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("rows affected: %w", err)
	}
	if rowsAffected == 0 {
		return fmt.Errorf("release not found: %s", rgid)
	}

	return nil
}

// GetExternalReleasesByArtistWithCache returns cached external_release rows for a given artist_id
// that are within the specified TTL.
func GetExternalReleasesByArtistWithCache(db *DB, artistID string, ttl time.Duration) ([]ExternalRelease, error) {
	// cached_at is a TEXT DATETIME column serialized by the driver in the
	// "2006-01-02 15:04:05" UTC layout. Compare against an explicitly
	// formatted cutoff string in the same layout so the lexicographic
	// comparison does not depend on the driver's time serialization behavior.
	const layout = "2006-01-02 15:04:05"
	cutoff := time.Now().UTC().Add(-ttl).Format(layout)
	rows, err := db.Conn().Query(
		"SELECT rgid, artist_id, title, type, release_date, is_ignored, cached_at, secondary_types FROM external_releases WHERE artist_id = ? AND cached_at >= ?",
		artistID, cutoff,
	)
	if err != nil {
		return nil, fmt.Errorf("query cached external releases: %w", err)
	}
	defer rows.Close()

	var results []ExternalRelease
	for rows.Next() {
		var r ExternalRelease
		var releaseType sql.NullString
		var releaseDate sql.NullString
		var cachedAt sql.NullTime
		var secondaryTypes sql.NullString
		if err := rows.Scan(&r.RGID, &r.ArtistID, &r.Title, &releaseType, &releaseDate, &r.IsIgnored, &cachedAt, &secondaryTypes); err != nil {
			return nil, fmt.Errorf("scan cached external release: %w", err)
		}
		if releaseType.Valid {
			r.Type = releaseType.String
		}
		if releaseDate.Valid {
			r.ReleaseDate = releaseDate.String
		}
		if cachedAt.Valid {
			r.CachedAt = cachedAt.Time
		}
		if secondaryTypes.Valid {
			r.SecondaryTypes = splitSecondaryTypes(secondaryTypes.String)
		}
		results = append(results, r)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("iterate cached external releases: %w", err)
	}
	return results, nil
}