package engineversion

import (
	"errors"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestParseSemverNormalises(t *testing.T) {
	tests := []struct {
		input string
		want  string
	}{
		{"1.2.3", "v1.2.3"},
		{"v1.2.3", "v1.2.3"},
		{" v0.4.0 ", "v0.4.0"},
		{"v2.0.0-rc.1", "v2.0.0-rc.1"},
		{"v2.0.0+build.7", "v2.0.0+build.7"},
	}
	for _, tt := range tests {
		t.Run(tt.input, func(t *testing.T) {
			got, err := ParseSemver(tt.input)
			require.NoError(t, err)
			assert.Equal(t, tt.want, got)
		})
	}
}

func TestParseSemverRejects(t *testing.T) {
	tests := []string{
		"",
		"   ",
		"latest",
		"1",
		"1.2",
		"v1.2",
		"1.2.3.4",
		"v1.2.x",
	}
	for _, input := range tests {
		t.Run(input, func(t *testing.T) {
			_, err := ParseSemver(input)
			require.Error(t, err)
			assert.True(t, errors.Is(err, ErrInvalidSemver))
		})
	}
}

func TestIsPatchUpgrade(t *testing.T) {
	tests := []struct {
		name    string
		current string
		next    string
		want    bool
	}{
		{"same patch", "v1.2.3", "v1.2.3", true},
		{"patch bump", "v1.2.3", "v1.2.4", true},
		{"patch downgrade", "1.2.4", "1.2.0", true},
		{"prerelease patch", "v1.2.3", "v1.2.3-rc.1", true},
		{"minor bump", "v1.2.3", "v1.3.0", false},
		{"minor downgrade", "v1.2.3", "v1.1.9", false},
		{"major bump", "v1.2.3", "v2.0.0", false},
		{"major downgrade", "v2.0.0", "v1.9.9", false},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := IsPatchUpgrade(tt.current, tt.next)
			require.NoError(t, err)
			assert.Equal(t, tt.want, got)
		})
	}
}

func TestIsPatchUpgradeRejectsBadInputs(t *testing.T) {
	_, err := IsPatchUpgrade("garbage", "v1.2.3")
	require.Error(t, err)
	assert.True(t, errors.Is(err, ErrInvalidSemver))

	_, err = IsPatchUpgrade("v1.2.3", "")
	require.Error(t, err)
	assert.True(t, errors.Is(err, ErrInvalidSemver))
}