// internal/helpers/pagination/pagination.go (move out of template/*)
package templateHelper

import (
	"context"
	"database/sql"
	"fmt"
	"time"
)

// Whitelist
var allowedTables = map[string]struct{}{
	"user_messages":       {},
	"user_notifications":  {},
	"results_thunderball": {},
}

// GetTotalPages counts rows and returns (totalPages, totalCount).
func GetTotalPages(ctx context.Context, db *sql.DB, table, whereClause string, args []any, pageSize int) (int, int64, error) {
	if pageSize <= 0 {
		pageSize = 20
	}
	if _, ok := allowedTables[table]; !ok {
		return 1, 0, fmt.Errorf("table not allowed: %s", table)
	}

	q := fmt.Sprintf("SELECT COUNT(*) FROM %s", table)
	if whereClause != "" {
		q += " WHERE " + whereClause
	}

	var totalCount int64
	cctx, cancel := context.WithTimeout(ctx, 2*time.Second)
	defer cancel()

	if err := db.QueryRowContext(cctx, q, args...).Scan(&totalCount); err != nil {
		return 1, 0, fmt.Errorf("count %s: %w", table, err)
	}
	totalPages := int((totalCount + int64(pageSize) - 1) / int64(pageSize))
	if totalPages < 1 {
		totalPages = 1
	}
	return totalPages, totalCount, nil
}

func MakePageRange(current, total int) []int {
	if total < 1 {
		return []int{1}
	}

	pages := make([]int, 0, total)
	for i := 1; i <= total; i++ {
		pages = append(pages, i)
	}
	return pages
}

func ClampPage(p, total int) int {
	if p < 1 {
		return 1
	}
	if p > total {
		return total
	}
	return p
}
func OffsetLimit(page, pageSize int) (int, int) {
	if page < 1 {
		page = 1
	}
	return (page - 1) * pageSize, pageSize
}