package merch

import (
	"context"
	"database/sql"
)

type Labels interface {
	createLabel(ctx context.Context, userId int64, label *Label) error
	getLabels(ctx context.Context, userId int64) ([]LabelsList, error)
	updateLabel(ctx context.Context, userId int64, label *Label) error
	deleteLabel(ctx context.Context, userId int64, labelUuid string, now sql.NullTime) error

	attachLabel(ctx context.Context, userId int64, label *LabelLink) error
	detachLabel(ctx context.Context, userId int64, label *LabelLink) error

	getManyAttachedLabelsByList(ctx context.Context, userId int64, list []int64) (map[int64][]string, error)
	getAttachedLabelsByUuid(ctx context.Context, userId int64, merchUuid string) ([]string, error)
}

func (r *repo) createLabel(ctx context.Context, userId int64, l *Label) error {
	q := `
		INSERT INTO labels (created_at, updated_at, deleted_at, user_id, uuid, name, color, bg_color)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
	`
	_, err := r.db.Exec(ctx, q, l.CreatedAt, l.UpdatedAt, l.DeletedAt, userId, l.Uuid, l.Name, l.Color, l.BgColor)
	if err != nil {
		return err
	}

	return nil
}

func (r *repo) getLabels(ctx context.Context, userId int64) ([]LabelsList, error) {
	q := `
		SELECT uuid, name, color, bg_color 
		FROM labels
		WHERE user_id = $1
		AND deleted_at IS NULL
		`

	rows, err := r.db.Query(ctx, q, userId)
	if err != nil {
		return nil, err
	}

	var labels []LabelsList
	for rows.Next() {
		var l LabelsList
		if err = rows.Scan(&l.LabelUuid, &l.Name, &l.Color, &l.BgColor); err != nil {
			rows.Close()
			return nil, err
		}
		labels = append(labels, l)
	}

	rows.Close()
	if err = rows.Err(); err != nil {
		return nil, err
	}

	return labels, nil
}

func (r *repo) updateLabel(ctx context.Context, userId int64, l *Label) error {
	q := `
		UPDATE labels
		SET 
    		updated_at = $1,
    		name = COALESCE(NULLIF($2, ''), labels.name),
    		color = COALESCE(NULLIF($3, ''), labels.color),
    		bg_color = COALESCE(NULLIF($4, ''), labels.bg_color)
		WHERE uuid = $5
		AND user_id = $6;
	`

	_, err := r.db.Exec(ctx, q, l.UpdatedAt, l.Name, l.Color, l.BgColor, l.Uuid, userId)
	if err != nil {
		return err
	}

	return nil
}

func (r *repo) deleteLabel(ctx context.Context, userId int64, labelUuid string, now sql.NullTime) error {
	q := `UPDATE labels SET deleted_at = &1 WHERE user_id = $2 AND uuid = $3`
	_, err := r.db.Exec(ctx, q, now, userId, labelUuid)
	if err != nil {
		return err
	}
	return nil
}

func (r *repo) attachLabel(ctx context.Context, userId int64, label *LabelLink) error {
	q := `
		INSERT INTO card_labels (user_id, label_id, merch_id)
		VALUES ($1, (SELECT id FROM labels WHERE uuid = $2), (SELECT id FROM merch WHERE merch_uuid = $3 AND user_id = $1))
		`
	_, err := r.db.Exec(ctx, q, userId, label.LabelUuid, label.MerchUuid)
	if err != nil {
		return err
	}
	return nil
}

func (r *repo) detachLabel(ctx context.Context, userId int64, label *LabelLink) error {
	q := `
		DELETE FROM card_labels
		WHERE user_id = $1
		AND label_id = (SELECT id FROM labels WHERE uuid = $2)
		AND merch_id = (SELECT id FROM merch WHERE merch_uuid = $3 AND user_id = $1)
	`
	_, err := r.db.Exec(ctx, q, userId, label.LabelUuid, label.MerchUuid)
	if err != nil {
		return err
	}
	return nil
}

func (r *repo) getManyAttachedLabelsByList(ctx context.Context, userId int64, list []int64) (map[int64][]string, error) {
	q := `
		SELECT l.uuid, cl.merch_id
		FROM card_labels AS cl
		JOIN labels AS l ON cl.label_id = l.id
		WHERE cl.user_id = $1
		AND cl.merch_id = ANY($2)
		AND l.deleted_at IS NULL
	`
	rows, err := r.db.Query(ctx, q, userId, list)
	if err != nil {
		return nil, err
	}

	cardLabelsMap := make(map[int64][]string)

	for rows.Next() {
		var (
			merchId   int64
			labelUuid string
		)

		if err = rows.Scan(&labelUuid, &merchId); err != nil {
			rows.Close()
			return nil, err
		}
		cardLabelsMap[merchId] = append(cardLabelsMap[merchId], labelUuid)
	}

	rows.Close()
	if err = rows.Err(); err != nil {
		return nil, err
	}

	return cardLabelsMap, nil
}

func (r *repo) getAttachedLabelsByUuid(ctx context.Context, userId int64, merchUuid string) ([]string, error) {
	q := `
		SELECT l.uuid
		FROM card_labels AS cl
		JOIN labels AS l ON cl.label_id = l.id
		WHERE cl.merch_id = (SELECT id FROM merch WHERE merch_uuid = $2 AND user_id = $1 AND deleted_at IS NULL)
		AND cl.user_id = $1
		AND l.deleted_at IS NULL
	`

	rows, err := r.db.Query(ctx, q, userId, merchUuid)
	if err != nil {
		return nil, err
	}

	var labels []string
	for rows.Next() {
		var label string
		if err = rows.Scan(&label); err != nil {
			rows.Close()
			return nil, err
		}
		labels = append(labels, label)
	}

	return labels, nil
}