// Package palindrome deals with palindrome products.
package palindrome
import (
	"fmt"
	"strconv"
)
// Product represents a product number with all the factors.
type Product struct {
	Product        int
	Factorizations [][2]int
}
// Products finds palindrome products between fmin and fmax.
func Products(fmin, fmax int) (pmin, pmax Product, err error) {
	if fmin > fmax {
		return Product{}, Product{}, fmt.Errorf("fmin > fmax")
	}
	for i := fmin; i <= fmax; i++ {
		for j := i; j <= fmax; j++ {
			if pal(i * j) {
				if pmin.Product == 0 {
					pmin = Product{i * j, [][2]int{{i, j}}}
				}
				if i*j == pmax.Product {
					pmax.Factorizations = append(pmax.Factorizations, [2]int{i, j})
				}
				if i*j > pmax.Product {
					pmax = Product{i * j, [][2]int{{i, j}}}
				}
			}
		}
	}
	if pmin.Product == 0 && pmax.Product == 0 {
		return Product{}, Product{}, fmt.Errorf("no palindromes...")
	}
	return pmin, pmax, nil
}
func pal(in int) bool {
	s := strconv.Itoa(in)
	for i := 0; i < len(s)/2; i++ {
		if s[i] != s[len(s)-1-i] {
			return false
		}
	}
	return true
}