"""
Copyright 2018-present, Facebook, Inc.

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.
"""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

import hashlib
import re

from .codegen import Language
from .cpp import entry_types as cpp_entry_types  # noqa: E402
from .cpp import entry_structs as cpp_entry_structs  # noqa: E402
from .cpp import parser as cpp_parser  # noqa: E402
from .java import entry_types as java_entry_types  # noqa: E402


class CodegenProgram(object):
    ENTRY_TYPES = 1
    ENTRY_TYPES_CPP = 2
    ENTRY_STRUCTS = 3
    ENTRY_STRUCTS_CPP = 4
    PARSER = 5

    SUPPORTED_CODEGEN = {
        Language.CPP: {
            ENTRY_TYPES: cpp_entry_types.CppEntryTypesCodegen,
            ENTRY_TYPES_CPP: cpp_entry_types.CppEntryTypesCppCodegen,
            ENTRY_STRUCTS: cpp_entry_structs.CppEntryStructsCodegen,
            ENTRY_STRUCTS_CPP: cpp_entry_structs.CppEntryStructsCppCodegen,
            PARSER: cpp_parser.CppParserCodegen,
        },
        Language.JAVA: {ENTRY_TYPES: java_entry_types.JavaEntryTypesCodegen},
    }

    # hide the pattern from tools
    SIGNED_SOURCE_PATTERN = re.compile(
        r"".join([r"@", r"generated", r" ", r"SignedSource", r"<<.*>>"])
    )

    # hide the pattern from tools
    SIGNED_SOURCE_REPLACE_PATTERN = "".join(
        [r"@", r"generated", r" ", r"SignedSource", r"<<{0}>>"]
    )
    SIGNED_SOURCE_TOKEN = "".join(
        ["@", "generated", " ", "<<SignedSource::*O*zOeWoEQle#+L!plEphiEmie@IsG>>"]
    )

    def __init__(self, lang, mode, entries):
        known_codegen = set(
            [
                y
                for x in list(CodegenProgram.SUPPORTED_CODEGEN.values())
                for y in list(x.keys())
            ]
        )

        if mode not in known_codegen:
            raise ValueError("Unknown mode {}".format(mode))

        if not Language.is_valid(lang):
            raise ValueError("Unknown language {}".format(lang))

        codegen_class = CodegenProgram.SUPPORTED_CODEGEN.get(lang, {}).get(mode, None)

        if codegen_class is None:
            raise ValueError(
                "The combination (lang: {}, mode: {}) is not "
                "currently supported".format(lang, mode)
            )

        self.lang = lang
        self.mode = mode
        self.entries = entries
        self.codegen_class = codegen_class

    def run(self):
        instance = self.codegen_class(self.entries)
        output = instance.generate()
        output = CodegenProgram.sign_source(output)

        return output

    @staticmethod
    def sign_source(text):

        in_text_pattern = CodegenProgram.SIGNED_SOURCE_REPLACE_PATTERN.format("")
        fixed_token_text = text.replace(
            in_text_pattern, CodegenProgram.SIGNED_SOURCE_TOKEN
        )

        digest = hashlib.md5(fixed_token_text).hexdigest()

        actual_hash = CodegenProgram.SIGNED_SOURCE_REPLACE_PATTERN.format(digest)

        return CodegenProgram.SIGNED_SOURCE_PATTERN.sub(actual_hash, text)