"""
合并多个 pdf 到一个，使用方式：放到当前文件夹下运行
"""

import os.path

from pyPdf import PdfFileReader, PdfFileWriter # pip install pyPdf


def get_pdf_files(dst_dir):
    paths = []
    for root, dirs, files in os.walk(dst_dir):
        for filespath in files:
            if filespath.endswith('.pdf'):  # pdf file
                abspath = os.path.join(root, filespath)
                paths.append(abspath)
    return paths


##########################合并同一个文件夹下所有PDF文件########################
def merge_pdf(dst_dir, outfile, sort=True):
    output = PdfFileWriter()
    curpage = 0
    pdf_paths = sorted(get_pdf_files(dst_dir)) if sort else get_pdf_files(dst_dir)
    for each in pdf_paths:
        print(each)
        reader = PdfFileReader(file(each, "rb"))
        # 如果pdf文件已经加密，必须首先解密才能使用pyPdf
        if reader.isEncrypted == True:
            reader.decrypt("map")
        # 获得源pdf文件中页面总数
        page_count = reader.getNumPages()
        curpage += page_count
        print(page_count)

        for iPage in range(0, page_count):
            output.addPage(reader.getPage(iPage))

    print("All Pages Number:" + str(curpage))
    outputStream = file(dst_dir + outfile, "wb")
    output.write(outputStream)
    outputStream.close()


def main():
    merged = "all.pdf"
    merge_pdf("./", merged)


if __name__ == '__main__':
    main()