#!/usr/bin/python
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"""Compile an .idl file to Blink V8 bindings (.h and .cpp files).

Design doc: http://www.chromium.org/developers/design-documents/idl-compiler
"""

import abc
from optparse import OptionParser
import os
import cPickle as pickle
import sys

from code_generator_v8 import CodeGeneratorV8
from idl_reader import IdlReader
from utilities import write_file


def parse_options():
    parser = OptionParser()
    parser.add_option('--cache-directory',
                      help='cache directory, defaults to output directory')
    parser.add_option('--output-directory')
    parser.add_option('--interfaces-info-file')
    parser.add_option('--write-file-only-if-changed', type='int')
    # ensure output comes last, so command line easy to parse via regexes
    parser.disable_interspersed_args()

    options, args = parser.parse_args()
    if options.output_directory is None:
        parser.error('Must specify output directory using --output-directory.')
    options.write_file_only_if_changed = bool(options.write_file_only_if_changed)
    if len(args) != 1:
        parser.error('Must specify exactly 1 input file as argument, but %d given.' % len(args))
    idl_filename = os.path.realpath(args[0])
    return options, idl_filename


def idl_filename_to_interface_name(idl_filename):
    basename = os.path.basename(idl_filename)
    interface_name, _ = os.path.splitext(basename)
    return interface_name


class IdlCompiler(object):
    """Abstract Base Class for IDL compilers.

    In concrete classes:
    * self.code_generator must be set, implementing generate_code()
      (returning a list of output code), and
    * compile_file() must be implemented (handling output filenames).
    """
    __metaclass__ = abc.ABCMeta

    def __init__(self, output_directory, cache_directory='',
                 code_generator=None, interfaces_info=None,
                 interfaces_info_filename='', only_if_changed=False):
        """
        Args:
            interfaces_info:
                interfaces_info dict
                (avoids auxiliary file in run-bindings-tests)
            interfaces_info_file: filename of pickled interfaces_info
        """
        cache_directory = cache_directory or output_directory
        self.cache_directory = cache_directory
        self.code_generator = code_generator
        if interfaces_info_filename:
            with open(interfaces_info_filename) as interfaces_info_file:
                interfaces_info = pickle.load(interfaces_info_file)
        self.interfaces_info = interfaces_info
        self.only_if_changed = only_if_changed
        self.output_directory = output_directory
        self.reader = IdlReader(interfaces_info, cache_directory)

    def compile_and_write(self, idl_filename):
        interface_name = idl_filename_to_interface_name(idl_filename)
        definitions = self.reader.read_idl_definitions(idl_filename)
        output_code_list = self.code_generator.generate_code(
            definitions, interface_name)
        for output_path, output_code in output_code_list:
            write_file(output_code, output_path, self.only_if_changed)

    @abc.abstractmethod
    def compile_file(self, idl_filename):
        pass


class IdlCompilerV8(IdlCompiler):
    def __init__(self, *args, **kwargs):
        IdlCompiler.__init__(self, *args, **kwargs)
        self.code_generator = CodeGeneratorV8(self.interfaces_info,
                                              self.cache_directory,
                                              self.output_directory)

    def compile_file(self, idl_filename):
        self.compile_and_write(idl_filename)


def main():
    options, idl_filename = parse_options()
    idl_compiler = IdlCompilerV8(
        options.output_directory,
        cache_directory=options.cache_directory,
        interfaces_info_filename=options.interfaces_info_file,
        only_if_changed=options.write_file_only_if_changed)
    idl_compiler.compile_file(idl_filename)


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