package matrix

import (
	"errors"
	"fmt"
	"strconv"
	"strings"
)

// Matrix is a grid of ints
type Matrix struct {
	vals [][]int
}

type Pair [2]int

// New creates a new Matrix from a string of numbers
func New(in string) (*Matrix, error) {
	ret := Matrix{}
	rows := strings.Split(in, "\n")
	for i := range rows {
		flds := strings.Fields(rows[i])
		var ints []int
		for j := range flds {
			if v, err := strconv.Atoi(flds[j]); err != nil {
				return &ret, err
			} else {
				ints = append(ints, v)
			}
		}
		ret.vals = append(ret.vals, ints)
	}
	numInRow := -1
	for i := range ret.vals {
		if numInRow != -1 {
			if len(ret.vals[i]) != numInRow {
				return &ret, errors.New("All rows must be equal length")
			}
		}
		numInRow = len(ret.vals[i])
	}
	return &ret, nil
}

func (m *Matrix) Saddle() []Pair {
	var ret []Pair
	// We're going to get a list of coords for row highs
	// then compare that to a list of coords for col lows
	var testRows []Pair
	for i := range m.vals {
		testRows = append(testRows, Pair{i, m.findRowHigh(i)})
	}
	fmt.Println(testRows)
	return ret
	for j := range m.vals[0] {
		v := Pair{m.findColLow(j), j}
		// If this pair is in testRows, it's a saddle point
		for i := range testRows {
			if v[0] == testRows[i][0] && v[1] == testRows[i][1] {
				ret = append(ret, v)
			}
		}
	}
	return ret
}

// Cols returns the values of the cols in the matrix
func (m *Matrix) Cols() [][]int {
	var ret [][]int
	for i := range m.vals[0] {
		var row []int
		for j := range m.vals {
			row = append(row, m.vals[j][i])
		}
		ret = append(ret, row)
	}
	return ret
}

// findColLow finds the lowest value in a column
func (m *Matrix) findColLow(c int) int {
	cols := m.Cols()
	var idx int
	val := -1
	if c >= 0 && c < len(cols) {
		for i := range cols[c] {
			if cols[c][i] < val || val == -1 {
				val = cols[c][i]
				idx = i
			}
		}
	}
	return idx
}

// findColLow finds the lowest value in a column
func (m *Matrix) findRowHigh(r int) int {
	var idx int
	val := -1
	if r >= 0 && r < len(m.vals) {
		for i := range m.vals[r] {
			if m.vals[r][i] < val || val == -1 {
				val = m.vals[r][i]
				idx = i
			}
		}
	}
	return idx
}