/*
 * Minio Cloud Storage, (C) 2015, 2016 Minio, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cmd

import (
	"errors"
	"strconv"
	"testing"
	"time"
)

const MiB = 1024 * 1024

// Test xlMetaV1.AddObjectPart()
func TestAddObjectPart(t *testing.T) {
	testCases := []struct {
		partNum       int
		expectedIndex int
	}{
		{1, 0},
		{2, 1},
		{4, 2},
		{5, 3},
		{7, 4},
		// Insert part.
		{3, 2},
		// Replace existing part.
		{4, 3},
		// Missing part.
		{6, -1},
	}

	// Setup.
	xlMeta := newXLMetaV1("test-object", 8, 8)
	if !xlMeta.IsValid() {
		t.Fatalf("unable to get xl meta")
	}

	// Test them.
	for _, testCase := range testCases {
		if testCase.expectedIndex > -1 {
			partNumString := strconv.Itoa(testCase.partNum)
			xlMeta.AddObjectPart(testCase.partNum, "part."+partNumString, "etag."+partNumString, int64(testCase.partNum+MiB))
		}

		if index := objectPartIndex(xlMeta.Parts, testCase.partNum); index != testCase.expectedIndex {
			t.Fatalf("%+v: expected = %d, got: %d", testCase, testCase.expectedIndex, index)
		}
	}
}

// Test objectPartIndex().
// generates a sample xlMeta data and asserts the output of objectPartIndex() with the expected value.
func TestObjectPartIndex(t *testing.T) {
	testCases := []struct {
		partNum       int
		expectedIndex int
	}{
		{2, 1},
		{1, 0},
		{5, 3},
		{4, 2},
		{7, 4},
	}

	// Setup.
	xlMeta := newXLMetaV1("test-object", 8, 8)
	if !xlMeta.IsValid() {
		t.Fatalf("unable to get xl meta")
	}

	// Add some parts for testing.
	for _, testCase := range testCases {
		partNumString := strconv.Itoa(testCase.partNum)
		xlMeta.AddObjectPart(testCase.partNum, "part."+partNumString, "etag."+partNumString, int64(testCase.partNum+MiB))
	}

	// Add failure test case.
	testCases = append(testCases, struct {
		partNum       int
		expectedIndex int
	}{6, -1})

	// Test them.
	for _, testCase := range testCases {
		if index := objectPartIndex(xlMeta.Parts, testCase.partNum); index != testCase.expectedIndex {
			t.Fatalf("%+v: expected = %d, got: %d", testCase, testCase.expectedIndex, index)
		}
	}
}

// Test xlMetaV1.ObjectToPartOffset().
func TestObjectToPartOffset(t *testing.T) {
	// Setup.
	xlMeta := newXLMetaV1("test-object", 8, 8)
	if !xlMeta.IsValid() {
		t.Fatalf("unable to get xl meta")
	}

	// Add some parts for testing.
	// Total size of all parts is 5,242,899 bytes.
	for _, partNum := range []int{1, 2, 4, 5, 7} {
		partNumString := strconv.Itoa(partNum)
		xlMeta.AddObjectPart(partNum, "part."+partNumString, "etag."+partNumString, int64(partNum+MiB))
	}

	testCases := []struct {
		offset         int64
		expectedIndex  int
		expectedOffset int64
		expectedErr    error
	}{
		{0, 0, 0, nil},
		{MiB, 0, MiB, nil},
		{1 + MiB, 1, 0, nil},
		{2 + MiB, 1, 1, nil},
		// Its valid for zero sized object.
		{-1, 0, -1, nil},
		// Max fffset is always (size - 1).
		{(1 + 2 + 4 + 5 + 7) + (5 * MiB) - 1, 4, 1048582, nil},
		// Error if offset is size.
		{(1 + 2 + 4 + 5 + 7) + (5 * MiB), 0, 0, InvalidRange{}},
	}

	// Test them.
	for _, testCase := range testCases {
		index, offset, err := xlMeta.ObjectToPartOffset(testCase.offset)
		err = errorCause(err)
		if err != testCase.expectedErr {
			t.Fatalf("%+v: expected = %s, got: %s", testCase, testCase.expectedErr, err)
		}
		if index != testCase.expectedIndex {
			t.Fatalf("%+v: index: expected = %d, got: %d", testCase, testCase.expectedIndex, index)
		}
		if offset != testCase.expectedOffset {
			t.Fatalf("%+v: offset: expected = %d, got: %d", testCase, testCase.expectedOffset, offset)
		}
	}
}

// Helper function to check if two xlMetaV1 values are similar.
func isXLMetaSimilar(m, n xlMetaV1) bool {
	if m.Version != n.Version {
		return false
	}
	if m.Format != n.Format {
		return false
	}
	if len(m.Parts) != len(n.Parts) {
		return false
	}
	return true
}

func TestPickValidXLMeta(t *testing.T) {
	obj := "object"
	x1 := newXLMetaV1(obj, 4, 4)
	now := time.Now().UTC()
	x1.Stat.ModTime = now
	invalidX1 := x1
	invalidX1.Version = "invalid-version"
	xs := []xlMetaV1{x1, x1, x1, x1}
	invalidXS := []xlMetaV1{invalidX1, invalidX1, invalidX1, invalidX1}
	testCases := []struct {
		metaArr     []xlMetaV1
		modTime     time.Time
		xlMeta      xlMetaV1
		expectedErr error
	}{
		{
			metaArr:     xs,
			modTime:     now,
			xlMeta:      x1,
			expectedErr: nil,
		},
		{
			metaArr:     invalidXS,
			modTime:     now,
			xlMeta:      invalidX1,
			expectedErr: errors.New("No valid xl.json present"),
		},
	}
	for i, test := range testCases {
		xlMeta, err := pickValidXLMeta(test.metaArr, test.modTime)
		if test.expectedErr != nil {
			if errorCause(err).Error() != test.expectedErr.Error() {
				t.Errorf("Test %d: Expected to fail with %v but received %v",
					i+1, test.expectedErr, err)
			}
		} else {
			if !isXLMetaSimilar(xlMeta, test.xlMeta) {
				t.Errorf("Test %d: Expected %v but received %v",
					i+1, test.xlMeta, xlMeta)
			}
		}
	}
}