package docstract

import (
	"bytes"
	"strings"
	"sync"

	"github.com/pkg/errors"
	"github.com/richardlehane/mscfb"
)

//Extract takes a .msg files binary data and returns an array of attachments and a count of how many files were extracted
func Extract(data []byte) (*[]*DocStract, int, error) {

	reader := bytes.NewReader(data)

	doc, err := mscfb.New(reader)

	if err != nil {
		return nil, 0, errors.Wrap(err, "creating reader")
	}

	files := []*DocStract{}

	{ // Get all the attachments seperated to parse
		attachment := false
		file := 0
		for entry, err := doc.Next(); err == nil; entry, err = doc.Next() {

			if strings.Contains(entry.Name, "attach") {
				files = append(files, &DocStract{})
				attachment = true
				continue
			}
			if attachment && strings.Contains(entry.Name, "properties") {
				attachment = false
				file++
				continue
			}

			if attachment {
				buf := make([]byte, entry.Size)
				i, _ := entry.Read(buf)
				if i > 0 {
					files[file].Bytes = append(files[file].Bytes, buf[:i]...)
				}
			}
		}
	}

	{ //Determine FileType and FileName
		wait := sync.WaitGroup{}
		for _, doc := range files {
			wait.Add(1)
			go func(d *DocStract) {
				d.getName()
				wait.Done()
			}(doc)
		}
		wait.Wait()
	}

	return &files, len(files), nil
}