package fp

import (
	"reflect"
	"testing"
)

func TestMap(t *testing.T) {
	tests := []struct {
		name     string
		input    []int
		function func(int) int
		want     []int
	}{
		{
			name:     "multiply by 2",
			input:    []int{1, 2, 3},
			function: func(x int) int { return x * 2 },
			want:     []int{2, 4, 6},
		},
		{
			name:     "add 1",
			input:    []int{1, 2, 3},
			function: func(x int) int { return x + 1 },
			want:     []int{2, 3, 4},
		},
		{
			name:     "subtract 5",
			input:    []int{10, 15, 20},
			function: func(x int) int { return x - 5 },
			want:     []int{5, 10, 15},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := Map(tt.input, tt.function)
			if !reflect.DeepEqual(got, tt.want) {
				t.Errorf("Map() = %v, want %v", got, tt.want)
			}
		})
	}
}

func TestFold(t *testing.T) {
	tests := []struct {
		name        string
		input       []int
		accumulator int
		function    func(int, int) int
		want        int
	}{
		{
			name:        "sum",
			input:       []int{1, 2, 3},
			accumulator: 0,
			function:    func(a, b int) int { return a + b },
			want:        6,
		},
		{
			name:        "product",
			input:       []int{1, 2, 3},
			accumulator: 1,
			function:    func(a, b int) int { return a * b },
			want:        6,
		},
		{
			name:        "maximum",
			input:       []int{1, 2, 3},
			accumulator: 0,
			function: func(a, b int) int {
				if a > b {
					return a
				}
				return b
			},
			want: 3,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := Fold(tt.input, tt.accumulator, tt.function)
			if !reflect.DeepEqual(got, tt.want) {
				t.Errorf("Fold() = %v, want %v", got, tt.want)
			}
		})
	}
}