package imageprocessor

import (
	"bytes"
	"errors"
	"testing"
)

// TestImageProcessor_RefusesComputedSideAboveMaximum verifies that a size
// with one side 0, which Process computes from the input's proportions, is
// served when that side comes out at MaxOutputDimension and refused with
// ErrOutputTooLarge when it would be above. A 4096x1 or 1x4096 input given
// 2 for its short side has 8192 for its long side.
func TestImageProcessor_RefusesComputedSideAboveMaximum(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name                    string
		inputWidth, inputHeight int
		size                    Size
		wantErr                 error
	}{
		{"width at the maximum", 4096, 1, Size{Height: 2}, nil},
		{"width above the maximum", 4096, 1, Size{Height: 3}, ErrOutputTooLarge},
		{"height at the maximum", 1, 4096, Size{Width: 2}, nil},
		{"height above the maximum", 1, 4096, Size{Width: 3}, ErrOutputTooLarge},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			input := createTestJPEG(t, tt.inputWidth, tt.inputHeight)

			result, err := New(Params{}).Process(t.Context(),
				bytes.NewReader(input),
				&Request{Size: tt.size, Format: FormatJPEG, FitMode: FitCover})
			if result != nil {
				t.Logf("Process() made %dx%d", result.Width, result.Height)

				if max(result.Width, result.Height) != MaxOutputDimension {
					t.Errorf("Process() made %dx%d, want a side of %d",
						result.Width, result.Height, MaxOutputDimension)
				}
			}

			if !errors.Is(err, tt.wantErr) {
				t.Errorf("Process() error = %v, want %v", err, tt.wantErr)
			}
		})
	}
}