package db

import (
	"context"
	"database/sql"
	"errors"
	"strings"
)

type Label struct {
	ID        int64
	RepoID    int64
	Name      string
	Color     string
	CreatedAt string
}

// placeholders returns "?, ?, ?" for an IN clause of n values.
func placeholders(n int) string {
	return strings.TrimSuffix(strings.Repeat("?, ", n), ", ")
}

func int64Args(ids []int64) []any {
	args := make([]any, len(ids))
	for i, id := range ids {
		args[i] = id
	}
	return args
}

func (d *DB) ListLabels(ctx context.Context, repoID int64) ([]Label, error) {
	rows, err := d.QueryContext(ctx,
		`SELECT id, repo_id, name, color, created_at FROM labels WHERE repo_id = ? ORDER BY name ASC`,
		repoID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return scanLabels(rows)
}

func scanLabels(rows *sql.Rows) ([]Label, error) {
	var out []Label
	for rows.Next() {
		var l Label
		if err := rows.Scan(&l.ID, &l.RepoID, &l.Name, &l.Color, &l.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, l)
	}
	return out, rows.Err()
}

// LabelInRepo returns the label only when it belongs to the given repo.
func (d *DB) LabelInRepo(ctx context.Context, id, repoID int64) (*Label, error) {
	var l Label
	err := d.QueryRowContext(ctx,
		`SELECT id, repo_id, name, color, created_at FROM labels WHERE id = ? AND repo_id = ?`,
		id, repoID).Scan(&l.ID, &l.RepoID, &l.Name, &l.Color, &l.CreatedAt)
	if errors.Is(err, sql.ErrNoRows) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return &l, nil
}

func (d *DB) CreateLabel(ctx context.Context, repoID int64, name, color, createdAt string) error {
	_, err := d.ExecContext(ctx,
		`INSERT INTO labels (repo_id, name, color, created_at) VALUES (?, ?, ?, ?)`,
		repoID, name, color, createdAt)
	return err
}

func (d *DB) DeleteLabel(ctx context.Context, id int64) error {
	_, err := d.ExecContext(ctx, `DELETE FROM labels WHERE id = ?`, id)
	return err
}