package tris

// Lines counts the number of lines that is completed and returns a Field with them removed
func (f Field) Lines() (int, Field) {
	var n int
	var nf [][]int

	full := func(line []int) bool {
		for _, el := range line {
			if el == 0 {
				return false
			}
		}
		return true
	}

	// count and collect
	for _, line := range f {
		if full(line) {
			n++
		} else {
			nf = append(nf, line)
		}
	}

	// compress
	for i := 0; i < 20; i++ {
		if i < n {
			f[i] = make([]int, len(f[0]))
		} else {
			f[i] = nf[i-n]
		}
	}
	return n, f
}