package pacificatlanticwaterflow

import (
	"sort"
	"testing"
)

func sortResult(result [][]int) {
	sort.Slice(result, func(i, j int) bool {
		if result[i][0] != result[j][0] {
			return result[i][0] < result[j][0]
		}
		return result[i][1] < result[j][1]
	})
}

func TestPacificAtlantic(t *testing.T) {
	tests := []struct {
		name     string
		heights  [][]int
		expected [][]int
	}{
		{
			name: "5x5 grid",
			heights: [][]int{
				{1, 2, 2, 3, 5},
				{3, 2, 3, 4, 4},
				{2, 4, 5, 3, 1},
				{6, 7, 1, 4, 5},
				{5, 1, 1, 2, 4},
			},
			expected: [][]int{{0, 4}, {1, 3}, {1, 4}, {2, 2}, {3, 0}, {3, 1}, {4, 0}},
		},
		{
			name: "3x2 all ones",
			heights: [][]int{
				{1, 1},
				{1, 1},
				{1, 1},
			},
			expected: [][]int{{0, 0}, {0, 1}, {1, 0}, {1, 1}, {2, 0}, {2, 1}},
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			result := PacificAtlantic(tc.heights)
			sortResult(result)
			sortResult(tc.expected)

			if len(result) != len(tc.expected) {
				t.Fatalf("expected %d results, got %d: %v", len(tc.expected), len(result), result)
			}

			for i := range tc.expected {
				if result[i][0] != tc.expected[i][0] || result[i][1] != tc.expected[i][1] {
					t.Errorf("result[%d] = %v, expected %v", i, result[i], tc.expected[i])
				}
			}
		})
	}
}