from hachoir_py3.parser import createParser
from hachoir_py3.core.tools import makePrintable
from hachoir_py3.metadata import extractMetadata
from hachoir_py3.core.i18n import initLocale
from sys import argv, stderr, exit
from os import walk
from os.path import join as path_join
from fnmatch import fnmatch
import codecs

OUTPUT_FILENAME = "metadata.csv"


class Extractor:

    def __init__(self, directory, fields):
        self.directory = directory
        self.fields = fields
        self.charset = "UTF-8"
        self.total = 0
        self.invalid = 0

    def main(self):
        output = codecs.open(OUTPUT_FILENAME, "w", self.charset)
        for filename in self.findFiles(self.directory, '*.doc'):
            self.total += 1
            line = self.processFile(filename)
            if line:
                print(line, file=output)
            else:
                self.invalid += 1
        output.close()
        self.summary()

    def summary(self):
        print(file=stderr)
        print("Valid files: %s" % (self.total - self.invalid), file=stderr)
        print("Invalid files: %s" % self.invalid, file=stderr)
        print("Total files: %s" % self.total, file=stderr)
        print(file=stderr)
        print("Result written into %s" % OUTPUT_FILENAME, file=stderr)

    def findFiles(self, directory, pattern):
        for dirpath, dirnames, filenames in walk(directory):
            for filename in filenames:
                if not fnmatch(filename.lower(), pattern):
                    continue
                yield path_join(dirpath, filename)

    def processFile(self, filename):
        print("[%s] Process file %s..." % (self.total, filename))
        parser = createParser(filename)
        if not parser:
            print("Unable to parse file", file=stderr)
            return None
        try:
            metadata = extractMetadata(parser)
        except Exception as err:
            print("Metadata extraction error: %s" % str(err), file=stderr)
            return None
        if not metadata:
            print("Unable to extract metadata", file=stderr)
            return None

        filename = makePrintable(filename, self.charset)
        line = [filename]
        for field in self.fields:
            value = metadata.getText(field, '')
            value = makePrintable(value, self.charset)
            line.append(value)
        return '; '.join(line)


def main():
    initLocale()
    if len(argv) != 3:
        print("usage: %s directory fields" % argv[0], file=stderr)
        print(file=stderr)
        print("eg. %s . title,creation_date" % argv[0], file=stderr)
        exit(1)
    directory = argv[1]
    fields = [field.strip() for field in argv[2].split(",")]
    Extractor(directory, fields).main()