package execution

import (
	"fmt"
	"github.com/j3ssie/osmedeus/utils"
	"github.com/robertkrimen/otto"
	"os"
	"path"
	"path/filepath"
	"strings"
)

/*

	SplitFile("src", "dest")
 	SplitFile("src", "base/dest", 500, "another/dest")
 	next step should be loop in file base/index

*/

// SplitFile split file into multiple file
func SplitFile(kind string, arguments []otto.Value) {
	source := arguments[0].String()
	dest := arguments[1].String()
	// prefix name of the output file
	prefix := fmt.Sprintf("%v-chunked", filepath.Base(source))
	destDir := filepath.Dir(utils.NormalizePath(dest))
	if len(arguments) >= 4 {
		destDir = arguments[3].String()
	}
	utils.MakeDir(destDir)

	chunk := 200
	// check if we change the size of it
	if len(arguments) >= 3 {
		chunkSize, _ := arguments[2].ToInteger()
		chunk = int(chunkSize)
	}

	chunkParts := chunk
	// get number of part
	if kind == "size" {
		length := utils.FileLength(source)
		chunkParts = length / chunk
	}

	utils.DebugF("Splitting %v to %v %v", source, chunkParts, kind)
	rawChunks, err := utils.SplitLineChunks(source, chunkParts)
	if err != nil || len(rawChunks) == 0 {
		utils.WarnF("error to split input file: %v", source)
		return
	}
	fp, err := os.Open(source)
	if err != nil {
		utils.WarnF("error to open input file: %v", source)
		return
	}

	var sumFile []string
	for index, offset := range rawChunks {
		targetName := path.Join(destDir, fmt.Sprintf("%v-%v", prefix, index))
		reader := utils.NewRangeReader(fp, offset.Start, offset.Stop)
		body := make([]byte, offset.Stop-offset.Start+1)
		_, err := reader.Read(body)
		if err != nil {
			utils.WarnF("error to read chunk file: %s", err)
			continue
		}
		sumFile = append(sumFile, targetName)
		utils.DebugF("writing %v part to: %v", index, targetName)
		utils.WriteToFile(targetName, string(body))
	}

	// write summary file
	indexFile := path.Join(destDir, dest)
	_, err = utils.WriteToFile(indexFile, strings.Join(sumFile, "\n"))
	if err != nil {
		utils.WarnF("Error writing to %v", indexFile)
	}
}

// ChunkFileByPart chunk file to multiple part
func ChunkFileByPart(source string, chunk int) [][]string {
	var divided [][]string
	data := utils.ReadingLines(source)
	if len(data) <= 0 || chunk > len(data) {
		if len(data) > 0 {
			divided = append(divided, data)
		}
		return divided
	}

	chunkSize := (len(data) + chunk - 1) / chunk
	for i := 0; i < len(data); i += chunkSize {
		end := i + chunkSize
		if end > len(data) {
			end = len(data)
		}

		divided = append(divided, data[i:end])
	}
	return divided
}

// ChunkFileBySize chunk file to multiple part
func ChunkFileBySize(source string, chunk int) [][]string {
	var divided [][]string
	data := utils.ReadingLines(source)
	if len(data) <= 0 || chunk > len(data) {
		if len(data) > 0 {
			divided = append(divided, data)
		}
		return divided
	}

	chunkSize := chunk
	for i := 0; i < len(data); i += chunkSize {
		end := i + chunkSize
		if end > len(data) {
			end = len(data)
		}

		divided = append(divided, data[i:end])
	}
	return divided
}