#!/usr/bin/env python3
# Copyright (C) 2017 MongoDB Inc.
#
# This program is free software: you can redistribute it and/or  modify
# it under the terms of the GNU Affero General Public License, version 3,
# as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
"""IDL Compiler Scons Tool."""

import os.path
import subprocess
import sys

import SCons

# We lazily import this at generate time.
idlc = None

IDL_GLOBAL_DEPS = []


def idlc_emitter(target, source, env):
    """For each input IDL file, the tool produces a .cpp and .h file."""
    first_source = str(source[0])

    if not first_source.endswith(".idl"):
        raise ValueError("Bad idl file name '%s', it must end with '.idl' " % (first_source))

    base_file_name, _ = SCons.Util.splitext(str(target[0]))
    target_source = base_file_name + "_gen.cpp"
    target_header = base_file_name + "_gen.h"

    env.Alias('generated-sources', [target_source, target_header])

    return [target_source, target_header], source


IDLCAction = SCons.Action.Action('$IDLCCOM', '$IDLCCOMSTR')


def idl_scanner(node, env, path):
    nodes_deps_list = getattr(node.attributes, "IDL_NODE_DEPS", None)
    if nodes_deps_list is not None:
        return nodes_deps_list

    nodes_deps_list = IDL_GLOBAL_DEPS[:]

    with open(str(node), encoding='utf-8') as file_stream:
        parsed_doc = idlc.parser.parse(file_stream, str(node),
                                       idlc.CompilerImportResolver(['src']))

    if not parsed_doc.errors and parsed_doc.spec.imports is not None:
        nodes_deps_list.extend([
            env.File(d) for d in sorted(parsed_doc.spec.imports.dependencies)
        ])

    setattr(node.attributes, "IDL_NODE_DEPS", nodes_deps_list)
    return nodes_deps_list


idl_scanner = SCons.Scanner.Scanner(function=idl_scanner, skeys=['.idl'])

# TODO: create a scanner for imports when imports are implemented
IDLCBuilder = SCons.Builder.Builder(action=IDLCAction, emitter=idlc_emitter, srcsuffx=".idl",
                                    suffix=".cpp", source_scanner=idl_scanner)


def generate(env):
    bld = IDLCBuilder

    env.Append(SCANNERS=idl_scanner)

    env['BUILDERS']['Idlc'] = bld

    sys.path.append(env.Dir("#buildscripts").get_abspath())
    import buildscripts.idl.idl.compiler as idlc_mod
    global idlc
    idlc = idlc_mod

    env['IDLC'] = sys.executable + " buildscripts/idl/idlc.py"
    env['IDLCFLAGS'] = ''
    base_dir = env.subst('$BUILD_ROOT/$VARIANT_DIR').replace("#", "")
    env['IDLCCOM'] = '$IDLC --include src --base_dir %s --target_arch $TARGET_ARCH --header ${TARGETS[1]} --output ${TARGETS[0]} $SOURCES ' % (
        base_dir)
    env['IDLCSUFFIX'] = '.idl'

    IDL_GLOBAL_DEPS = env.Glob('#buildscripts/idl/*.py') + env.Glob('#buildscripts/idl/idl/*.py')
    env['IDL_HAS_INLINE_DEPENDENCIES'] = True


def exists(env):
    return True