// Copyright 2017 Baliance. All rights reserved.
//
// Use of this source code is governed by the terms of the Affero GNU General
// Public License version 3.0 as published by the Free Software Foundation and
// appearing in the file LICENSE included in the packaging of this file. A
// commercial license can be purchased by contacting sales@baliance.com.

package spreadsheet

import (
	"archive/zip"
	"fmt"
	"io"
	"io/ioutil"
	"os"

	"baliance.com/gooxml"
	"baliance.com/gooxml/zippkg"
)

// Read reads a workbook from an io.Reader(.xlsx).
func Read(r io.ReaderAt, size int64) (*Workbook, error) {
	wb := New()
	td, err := ioutil.TempDir("", "gooxml-xlsx")
	if err != nil {
		return nil, err
	}
	wb.TmpPath = td

	zr, err := zip.NewReader(r, size)
	if err != nil {
		return nil, fmt.Errorf("parsing zip: %s", err)
	}

	files := []*zip.File{}
	files = append(files, zr.File...)
	decMap := zippkg.DecodeMap{}
	decMap.SetOnNewRelationshipFunc(wb.onNewRelationship)
	// we should discover all contents by starting with these two files
	decMap.AddTarget(gooxml.ContentTypesFilename, wb.ContentTypes.X(), "", 0)
	decMap.AddTarget(gooxml.BaseRelsFilename, wb.Rels.X(), "", 0)
	if err := decMap.Decode(files); err != nil {
		return nil, err
	}

	// etra files are things we don't handle yet, or files that happened to have
	// been in the zip before.  We just round-trip them.
	for _, f := range files {
		if f == nil {
			continue
		}
		if err := wb.AddExtraFileFromZip(f); err != nil {
			return nil, err
		}
	}
	return wb, nil
}

// Open opens and reads a workbook from a file (.xlsx).
func Open(filename string) (*Workbook, error) {
	f, err := os.Open(filename)
	if err != nil {
		return nil, fmt.Errorf("error opening %s: %s", filename, err)
	}
	defer f.Close()
	fi, err := os.Stat(filename)
	if err != nil {
		return nil, fmt.Errorf("error opening %s: %s", filename, err)
	}
	return Read(f, fi.Size())
}