#!/usr/bin/env python

# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

# author: Christian Berendt <berendt@b1-systems.de>

import argparse
import logging
import os
import sys

import jinja2


def initialize_logging(debug, verbose):
    """Initialze the Logger."""

    logger = logging.getLogger(name='logger')
    formatter = logging.Formatter('%(asctime)s %(levelname)-8s %(message)s')
    handler = logging.StreamHandler()
    handler.setFormatter(formatter)
    logger.addHandler(handler)

    if verbose:
        logger.setLevel(logging.INFO)

    if debug:
        logger.setLevel(logging.DEBUG)

    return logging.getLogger('logger')


def parse_command_line_arguments():
    """Parse the command line arguments."""
    parser = argparse.ArgumentParser()
    parser.add_argument("--debug", help="Print debugging messages.",
                        action="store_true", default=False)
    parser.add_argument("--verbose", help="Be more verbose.",
                        action="store_true", default=False)
    parser.add_argument("--source-directory", type=str,
                        default='www', help='')
    parser.add_argument("--output-directory", type=str,
                        default='publish-docs/www', help='')
    return parser.parse_args()


def main():
    """Entry point for this script."""

    args = parse_command_line_arguments()
    logger = initialize_logging(args.debug, args.verbose)

    try:
        loader = jinja2.FileSystemLoader(args.source_directory)
        environment = jinja2.Environment(loader=loader)
    except Exception as e:
        logger.error("initialising template environment failed: %s" % e)
        return 1

    for templateFile in environment.list_templates():
        if not templateFile.endswith('.html'):
            continue

        logger.info("generating %s" % templateFile)

        try:
            template = environment.get_template(templateFile)
        except Exception as e:
            logger.error("parsing template %s failed: %s" %
                         (templateFile, e))
            continue

        try:
            output = template.render()
        except Exception as e:
            logger.error("rendering template %s failed: %s" %
                         (templateFile, e))
            continue

        try:
            target_directory = os.path.join(args.output_directory,
                                            os.path.dirname(templateFile))
            target_file = os.path.join(args.output_directory, templateFile)
            if not os.path.isdir(target_directory):
                logger.debug("creating target directory %s" %
                             target_directory)
                os.makedirs(target_directory)
            logger.debug("writing %s" % target_file)
            with open(os.path.join(target_file), 'wb') as fh:
                fh.write(output.encode('utf8'))
        except (IOError, OSError, UnicodeEncodeError) as e:
            logger.error("writing %s failed: %s" % (target_file, e))
            continue

    return 0


if __name__ == '__main__':
    sys.exit(main())