// Copyright 2019 PingCAP, 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 mydump_test

import (
	"context"
	"os"
	"path/filepath"
	"testing"

	"github.com/pingcap/tidb/br/pkg/storage"
	"github.com/pingcap/tidb/pkg/lightning/config"
	. "github.com/pingcap/tidb/pkg/lightning/mydump"
	"github.com/pingcap/tidb/pkg/lightning/worker"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// var expectedTuplesCount = map[string]int64{
// 	"i":                     1,
// 	"report_case_high_risk": 1,
// 	"tbl_autoid":            10000,
// 	"tbl_multi_index":       10000,
// }

/*
TODO : test with specified 'regionBlockSize' ...
*/
func TestTableRegion(t *testing.T) {
	cfg := newConfigWithSourceDir("./examples")
	loader, _ := NewLoader(context.Background(), NewLoaderCfg(cfg))
	dbMeta := loader.GetDatabases()[0]

	ioWorkers := worker.NewPool(context.Background(), 1, "io")
	for _, meta := range dbMeta.Tables {
		divideConfig := NewDataDivideConfig(cfg, 1, ioWorkers, loader.GetStore(), meta)
		regions, err := MakeTableRegions(context.Background(), divideConfig)
		require.NoError(t, err)

		// check - region-size vs file-size
		var tolFileSize int64 = 0
		for _, file := range meta.DataFiles {
			tolFileSize += file.FileMeta.FileSize
		}
		var tolRegionSize int64 = 0
		for _, region := range regions {
			tolRegionSize += region.Size()
		}
		require.Equal(t, tolFileSize, tolRegionSize)

		// // check - rows num
		// var tolRows int64 = 0
		// for _, region := range regions {
		// 	tolRows += region.Rows()
		// }
		// c.Assert(tolRows, Equals, expectedTuplesCount[table])

		// check - range
		regionNum := len(regions)
		preReg := regions[0]
		for i := 1; i < regionNum; i++ {
			reg := regions[i]
			if preReg.FileMeta.Path == reg.FileMeta.Path {
				require.Equal(t, preReg.Offset()+preReg.Size(), reg.Offset())
				require.Equal(t, preReg.RowIDMin()+preReg.Rows(), reg.RowIDMin())
			} else {
				require.Equal(t, 0, reg.Offset())
				require.Equal(t, 1, reg.RowIDMin())
			}
			preReg = reg
		}
	}
}

func TestAllocateEngineIDs(t *testing.T) {
	dataFileSizes := make([]float64, 700)
	for i := range dataFileSizes {
		dataFileSizes[i] = 1.0
	}
	filesRegions := make([]*TableRegion, 0, len(dataFileSizes))
	for range dataFileSizes {
		filesRegions = append(filesRegions, new(TableRegion))
	}

	checkEngineSizes := func(what string, expected map[int32]int) {
		actual := make(map[int32]int)
		for _, region := range filesRegions {
			actual[region.EngineID]++
		}
		require.Equal(t, expected, actual, what)
	}

	// Batch size > Total size => Everything in the zero batch.
	AllocateEngineIDs(filesRegions, dataFileSizes, 1000, 0.5, 1000)
	checkEngineSizes("no batching", map[int32]int{
		0: 700,
	})

	// Allocate 3 engines.
	AllocateEngineIDs(filesRegions, dataFileSizes, 200, 0.5, 1000)
	checkEngineSizes("batch size = 200", map[int32]int{
		0: 170,
		1: 213,
		2: 317,
	})

	// Allocate 3 engines with an alternative ratio
	AllocateEngineIDs(filesRegions, dataFileSizes, 200, 0.6, 1000)
	checkEngineSizes("batch size = 200, ratio = 0.6", map[int32]int{
		0: 160,
		1: 208,
		2: 332,
	})

	// Allocate 5 engines.
	AllocateEngineIDs(filesRegions, dataFileSizes, 100, 0.5, 1000)
	checkEngineSizes("batch size = 100", map[int32]int{
		0: 93,
		1: 105,
		2: 122,
		3: 153,
		4: 227,
	})

	// Number of engines > table concurrency
	AllocateEngineIDs(filesRegions, dataFileSizes, 50, 0.5, 4)
	checkEngineSizes("batch size = 50, limit table conc = 4", map[int32]int{
		0:  50,
		1:  59,
		2:  73,
		3:  110,
		4:  50,
		5:  50,
		6:  50,
		7:  50,
		8:  50,
		9:  50,
		10: 50,
		11: 50,
		12: 8,
	})

	// Zero ratio = Uniform
	AllocateEngineIDs(filesRegions, dataFileSizes, 100, 0.0, 1000)
	checkEngineSizes("batch size = 100, ratio = 0", map[int32]int{
		0: 100,
		1: 100,
		2: 100,
		3: 100,
		4: 100,
		5: 100,
		6: 100,
	})
}

func TestMakeTableRegionsSplitLargeFile(t *testing.T) {
	cfg := &config.Config{
		Mydumper: config.MydumperRuntime{
			ReadBlockSize: config.ReadBlockSize,
			MaxRegionSize: 1,
			CSV: config.CSVConfig{
				Separator:         ",",
				Delimiter:         "",
				Header:            true,
				HeaderSchemaMatch: true,
				TrimLastSep:       false,
				NotNull:           false,
				Null:              []string{"NULL"},
				EscapedBy:         `\`,
			},
			StrictFormat: true,
			Filter:       []string{"*.*"},
		},
	}
	filePath := "./csv/split_large_file.csv"
	dataFileInfo, err := os.Stat(filePath)
	require.NoError(t, err)
	fileSize := dataFileInfo.Size()
	fileInfo := FileInfo{FileMeta: SourceFileMeta{Path: filePath, Type: SourceTypeCSV, FileSize: fileSize}}
	colCnt := 3
	columns := []string{"a", "b", "c"}
	meta := &MDTableMeta{
		DB:        "csv",
		Name:      "large_csv_file",
		DataFiles: []FileInfo{fileInfo},
	}

	ctx := context.Background()
	store, err := storage.NewLocalStorage(".")
	assert.NoError(t, err)

	meta.DataFiles[0].FileMeta.Compression = CompressionNone
	divideConfig := NewDataDivideConfig(cfg, colCnt, nil, store, meta)
	regions, err := MakeTableRegions(ctx, divideConfig)
	assert.NoError(t, err)
	offsets := [][]int64{{6, 12}, {12, 18}, {18, 24}, {24, 30}}
	assert.Len(t, regions, len(offsets))
	for i := range offsets {
		assert.Equal(t, offsets[i][0], regions[i].Chunk.Offset)
		assert.Equal(t, offsets[i][1], regions[i].Chunk.EndOffset)
		assert.Equal(t, columns, regions[i].Chunk.Columns)
	}

	// test - gzip compression
	meta.DataFiles[0].FileMeta.Compression = CompressionGZ
	regions, err = MakeTableRegions(ctx, divideConfig)
	assert.NoError(t, err)
	assert.Len(t, regions, 1)
	assert.Equal(t, int64(0), regions[0].Chunk.Offset)
	assert.Equal(t, TableFileSizeINF, regions[0].Chunk.EndOffset)
	assert.Len(t, regions[0].Chunk.Columns, 0)

	// test canceled context will not panic
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	for i := 0; i < 20; i++ {
		_, _ = MakeTableRegions(ctx, divideConfig)
	}
}

func TestCompressedMakeSourceFileRegion(t *testing.T) {
	meta := &MDTableMeta{
		DB:   "csv",
		Name: "large_csv_file",
	}
	filePath := "./csv/split_large_file.csv.zst"
	dataFileInfo, err := os.Stat(filePath)
	require.NoError(t, err)
	fileSize := dataFileInfo.Size()

	fileInfo := FileInfo{FileMeta: SourceFileMeta{
		Path:        filePath,
		Type:        SourceTypeCSV,
		Compression: CompressionZStd,
		FileSize:    fileSize,
	}}
	colCnt := 3

	ctx := context.Background()
	store, err := storage.NewLocalStorage(".")
	assert.NoError(t, err)
	compressRatio, err := SampleFileCompressRatio(ctx, fileInfo.FileMeta, store)
	require.NoError(t, err)
	fileInfo.FileMeta.RealSize = int64(compressRatio * float64(fileInfo.FileMeta.FileSize))

	divideConfig := &DataDivideConfig{
		ColumnCnt: colCnt,
		TableMeta: meta,
	}
	regions, sizes, err := MakeSourceFileRegion(ctx, divideConfig, fileInfo)
	assert.NoError(t, err)
	assert.Len(t, regions, 1)
	assert.Equal(t, int64(0), regions[0].Chunk.Offset)
	assert.Equal(t, int64(0), regions[0].Chunk.RealOffset)
	assert.Equal(t, TableFileSizeINF, regions[0].Chunk.EndOffset)
	rowIDMax := fileInfo.FileMeta.RealSize * CompressSizeFactor / int64(colCnt)
	assert.Equal(t, rowIDMax, regions[0].Chunk.RowIDMax)
	assert.Len(t, regions[0].Chunk.Columns, 0)
	assert.Equal(t, fileInfo.FileMeta.RealSize, int64(sizes[0]))
}

func TestSplitLargeFile(t *testing.T) {
	meta := &MDTableMeta{
		DB:   "csv",
		Name: "large_csv_file",
	}
	cfg := &config.Config{
		Mydumper: config.MydumperRuntime{
			ReadBlockSize: config.ReadBlockSize,
			CSV: config.CSVConfig{
				Separator:         ",",
				Delimiter:         "",
				Header:            true,
				HeaderSchemaMatch: true,
				TrimLastSep:       false,
				NotNull:           false,
				Null:              []string{"NULL"},
				EscapedBy:         `\`,
			},
			StrictFormat: true,
			Filter:       []string{"*.*"},
		},
	}
	filePath := "./csv/split_large_file.csv"
	dataFileInfo, err := os.Stat(filePath)
	require.NoError(t, err)
	fileSize := dataFileInfo.Size()
	fileInfo := FileInfo{FileMeta: SourceFileMeta{Path: filePath, Type: SourceTypeCSV, FileSize: fileSize}}
	ioWorker := worker.NewPool(context.Background(), 4, "io")
	store, err := storage.NewLocalStorage(".")
	assert.NoError(t, err)
	divideConfig := NewDataDivideConfig(cfg, 3, ioWorker, store, meta)
	columns := []string{"a", "b", "c"}
	for _, tc := range []struct {
		maxRegionSize config.ByteSize
		offsets       [][]int64
	}{
		{1, [][]int64{{6, 12}, {12, 18}, {18, 24}, {24, 30}}},
		{6, [][]int64{{6, 18}, {18, 30}}},
		{8, [][]int64{{6, 18}, {18, 30}}},
		{12, [][]int64{{6, 24}, {24, 30}}},
		{13, [][]int64{{6, 24}, {24, 30}}},
		{18, [][]int64{{6, 30}}},
		{19, [][]int64{{6, 30}}},
	} {
		divideConfig.MaxChunkSize = int64(tc.maxRegionSize)

		regions, _, err := SplitLargeCSV(context.Background(), divideConfig, fileInfo)
		assert.NoError(t, err)
		assert.Len(t, regions, len(tc.offsets))
		for i := range tc.offsets {
			assert.Equal(t, tc.offsets[i][0], regions[i].Chunk.Offset)
			assert.Equal(t, tc.offsets[i][1], regions[i].Chunk.EndOffset)
			assert.Equal(t, columns, regions[i].Chunk.Columns)
		}
	}
}

func TestSplitLargeFileNoNewLineAtEOF(t *testing.T) {
	meta := &MDTableMeta{
		DB:   "csv",
		Name: "large_csv_file",
	}
	cfg := &config.Config{
		Mydumper: config.MydumperRuntime{
			ReadBlockSize: config.ReadBlockSize,
			CSV: config.CSVConfig{
				Separator:         ",",
				Delimiter:         "",
				Header:            true,
				HeaderSchemaMatch: true,
				TrimLastSep:       false,
				NotNull:           false,
				Null:              []string{"NULL"},
				EscapedBy:         `\`,
			},
			StrictFormat:  true,
			Filter:        []string{"*.*"},
			MaxRegionSize: 1,
		},
	}

	dir := t.TempDir()

	fileName := "test.csv"
	filePath := filepath.Join(dir, fileName)

	content := []byte("a,b\r\n123,456\r\n789,101")
	err := os.WriteFile(filePath, content, 0o644)
	require.NoError(t, err)

	dataFileInfo, err := os.Stat(filePath)
	require.NoError(t, err)
	fileSize := dataFileInfo.Size()
	fileInfo := FileInfo{FileMeta: SourceFileMeta{Path: fileName, Type: SourceTypeCSV, FileSize: fileSize}}
	ioWorker := worker.NewPool(context.Background(), 4, "io")

	store, err := storage.NewLocalStorage(dir)
	require.NoError(t, err)
	divideConfig := NewDataDivideConfig(cfg, 2, ioWorker, store, meta)
	columns := []string{"a", "b"}

	offsets := [][]int64{{4, 13}, {13, 21}}

	regions, _, err := SplitLargeCSV(context.Background(), divideConfig, fileInfo)
	require.NoError(t, err)
	require.Len(t, regions, len(offsets))
	for i := range offsets {
		require.Equal(t, offsets[i][0], regions[i].Chunk.Offset)
		require.Equal(t, offsets[i][1], regions[i].Chunk.EndOffset)
		require.Equal(t, columns, regions[i].Chunk.Columns)
	}
}

func TestSplitLargeFileWithCustomTerminator(t *testing.T) {
	meta := &MDTableMeta{
		DB:   "csv",
		Name: "large_csv_with_custom_terminator",
	}
	cfg := &config.Config{
		Mydumper: config.MydumperRuntime{
			ReadBlockSize: config.ReadBlockSize,
			CSV: config.CSVConfig{
				Separator:  "|+|",
				Terminator: "|+|\n",
			},
			StrictFormat:  true,
			Filter:        []string{"*.*"},
			MaxRegionSize: 1,
		},
	}

	dir := t.TempDir()

	fileName := "test2.csv"
	filePath := filepath.Join(dir, fileName)

	content := []byte("5|+|abc\ndef\nghi|+|6|+|\n7|+|xyz|+|8|+|\n9|+||+|10")
	err := os.WriteFile(filePath, content, 0o644)
	require.NoError(t, err)

	dataFileInfo, err := os.Stat(filePath)
	require.NoError(t, err)
	fileSize := dataFileInfo.Size()
	fileInfo := FileInfo{FileMeta: SourceFileMeta{Path: fileName, Type: SourceTypeCSV, FileSize: fileSize}}
	ioWorker := worker.NewPool(context.Background(), 4, "io")

	store, err := storage.NewLocalStorage(dir)
	require.NoError(t, err)
	divideConfig := NewDataDivideConfig(cfg, 3, ioWorker, store, meta)

	offsets := [][]int64{{0, 23}, {23, 38}, {38, 47}}

	regions, _, err := SplitLargeCSV(context.Background(), divideConfig, fileInfo)
	require.NoError(t, err)
	require.Len(t, regions, len(offsets))
	for i := range offsets {
		require.Equal(t, offsets[i][0], regions[i].Chunk.Offset)
		require.Equal(t, offsets[i][1], regions[i].Chunk.EndOffset)
	}
}

func TestSplitLargeFileOnlyOneChunk(t *testing.T) {
	meta := &MDTableMeta{
		DB:   "csv",
		Name: "large_csv_file",
	}
	cfg := &config.Config{
		Mydumper: config.MydumperRuntime{
			ReadBlockSize: config.ReadBlockSize,
			CSV: config.CSVConfig{
				Separator:         ",",
				Delimiter:         "",
				Header:            true,
				HeaderSchemaMatch: true,
				TrimLastSep:       false,
				NotNull:           false,
				Null:              []string{"NULL"},
				EscapedBy:         `\`,
			},
			StrictFormat:  true,
			Filter:        []string{"*.*"},
			MaxRegionSize: 15,
		},
	}

	dir := t.TempDir()

	fileName := "test.csv"
	filePath := filepath.Join(dir, fileName)

	content := []byte("field1,field2\r\n123,456\r\n")
	err := os.WriteFile(filePath, content, 0o644)
	require.NoError(t, err)

	dataFileInfo, err := os.Stat(filePath)
	require.NoError(t, err)
	fileSize := dataFileInfo.Size()
	fileInfo := FileInfo{FileMeta: SourceFileMeta{Path: fileName, Type: SourceTypeCSV, FileSize: fileSize}}
	columns := []string{"field1", "field2"}
	ioWorker := worker.NewPool(context.Background(), 4, "io")

	store, err := storage.NewLocalStorage(dir)
	require.NoError(t, err)
	divideConfig := NewDataDivideConfig(cfg, 2, ioWorker, store, meta)

	offsets := [][]int64{{14, 24}}

	regions, _, err := SplitLargeCSV(context.Background(), divideConfig, fileInfo)
	require.NoError(t, err)
	require.Len(t, regions, len(offsets))
	for i := range offsets {
		require.Equal(t, offsets[i][0], regions[i].Chunk.Offset)
		require.Equal(t, offsets[i][1], regions[i].Chunk.EndOffset)
		require.Equal(t, columns, regions[i].Chunk.Columns)
	}
}

func TestSplitLargeFileSeekInsideCRLF(t *testing.T) {
	ctx := context.Background()
	meta := &MDTableMeta{
		DB:   "csv",
		Name: "large_csv_seek_inside_crlf",
	}

	dir := t.TempDir()

	fileName := "test.csv"
	filePath := filepath.Join(dir, fileName)

	content := []byte("1\r\n2\r\n3\r\n4\r\n")
	err := os.WriteFile(filePath, content, 0o644)
	require.NoError(t, err)

	dataFileInfo, err := os.Stat(filePath)
	require.NoError(t, err)
	fileSize := dataFileInfo.Size()
	fileInfo := FileInfo{FileMeta: SourceFileMeta{Path: fileName, Type: SourceTypeCSV, FileSize: fileSize}}
	ioWorker := worker.NewPool(context.Background(), 4, "io")

	store, err := storage.NewLocalStorage(dir)
	require.NoError(t, err)

	// if we don't set terminator, it will get the wrong result

	cfg := &config.Config{
		Mydumper: config.MydumperRuntime{
			ReadBlockSize: config.ReadBlockSize,
			CSV: config.CSVConfig{
				Separator: ",",
			},
			StrictFormat:  true,
			Filter:        []string{"*.*"},
			MaxRegionSize: 2,
		},
	}
	divideConfig := NewDataDivideConfig(cfg, 1, ioWorker, store, meta)

	// in fact this is the wrong result, just to show the bug. pos mismatch with
	// offsets. and we might read more rows than expected because we use == rather
	// than >= to stop reading.
	offsets := [][]int64{{0, 3}, {3, 6}, {6, 9}, {9, 12}}
	pos := []int64{2, 5, 8, 11}

	regions, _, err := SplitLargeCSV(context.Background(), divideConfig, fileInfo)
	require.NoError(t, err)
	require.Len(t, regions, len(offsets))
	for i := range offsets {
		require.Equal(t, offsets[i][0], regions[i].Chunk.Offset)
		require.Equal(t, offsets[i][1], regions[i].Chunk.EndOffset)
	}

	file, err := os.Open(filePath)
	require.NoError(t, err)
	parser, err := NewCSVParser(ctx, &cfg.Mydumper.CSV, file, 128, ioWorker, false, nil)
	require.NoError(t, err)

	for parser.ReadRow() == nil {
		p, _ := parser.Pos()
		require.Equal(t, pos[0], p)
		pos = pos[1:]
	}
	require.NoError(t, parser.Close())

	// set terminator to "\r\n"

	cfg.Mydumper.CSV.Terminator = "\r\n"
	divideConfig = NewDataDivideConfig(cfg, 1, ioWorker, store, meta)
	// pos is contained in expectedOffsets
	expectedOffsets := [][]int64{{0, 6}, {6, 12}}
	pos = []int64{3, 6, 9, 12}

	regions, _, err = SplitLargeCSV(context.Background(), divideConfig, fileInfo)
	require.NoError(t, err)
	require.Len(t, regions, len(expectedOffsets))
	for i := range expectedOffsets {
		require.Equal(t, expectedOffsets[i][0], regions[i].Chunk.Offset)
		require.Equal(t, expectedOffsets[i][1], regions[i].Chunk.EndOffset)
	}

	file, err = os.Open(filePath)
	require.NoError(t, err)
	parser, err = NewCSVParser(ctx, &cfg.Mydumper.CSV, file, 128, ioWorker, false, nil)
	require.NoError(t, err)

	for parser.ReadRow() == nil {
		p, _ := parser.Pos()
		require.Equal(t, pos[0], p)
		pos = pos[1:]
	}
	require.NoError(t, parser.Close())
}