// Package minesweeper handles minesweeper game.
package minesweeper
import (
	"fmt"
)
// Count counts mines related to each field.
func (b Board) Count() error {
	for j := range b {
		if len(b[j]) != len(b[0]) {
			return fmt.Errorf("non-square minefield")
		}
		if b[j][0] != '+' && b[j][0] != '|' {
			return fmt.Errorf("invalid minefield fence")
		}
		for i := range b[j] {
			if b[j][i] == 'X' {
				return fmt.Errorf("invalid field value")
			}
			if b[j][i] == ' ' {
				b[j][i] = b.countMines(j, i)
			}
		}
	}
	return nil
}
func (b Board) countMines(row, col int) byte {
	var sum byte
	for j := -1; j < 2; j++ {
		for i := -1; i < 2; i++ {
			// skip first and last row and column as those are just marking the minefield
			if row+j < 1 || row+j > len(b)-2 {
				continue
			}
			if col+i < 1 || col+i > len(b[0])-2 {
				continue
			}
			if b[row+j][col+i] == '*' {
				sum++
			}
		}
	}
	if sum == 0 {
		return ' '
	}
	return sum + 48 // convert to character
}