# Extension to generate Doxygen XML include files, with IDF config & soc macros included
from __future__ import print_function, unicode_literals

import os
import os.path
import re
import subprocess
from io import open

from .util import copy_if_modified

ALL_KINDS = [
    ('function', 'Functions'),
    ('union', 'Unions'),
    ('struct', 'Structures'),
    ('define', 'Macros'),
    ('typedef', 'Type Definitions'),
    ('enum', 'Enumerations')
]
"""list of items that will be generated for a single API file
"""


def setup(app):
    # The idf_build_system extension will emit this event once it has generated documentation macro definitions
    app.connect('idf-defines-generated', generate_doxygen)
    return {'parallel_read_safe': True, 'parallel_write_safe': True, 'version': '0.2'}


def generate_doxygen(app, defines):
    build_dir = os.path.dirname(app.doctreedir.rstrip(os.sep))

    # Call Doxygen to get XML files from the header files
    print('Calling Doxygen to generate latest XML files')
    doxy_env = os.environ
    doxy_env.update({
        'ENV_DOXYGEN_DEFINES': ' '.join('{}={}'.format(key, value) for key, value in defines.items()),
        'IDF_PATH': app.config.idf_path,
        'IDF_TARGET': app.config.idf_target,
    })
    doxyfile_dir = os.path.join(app.config.docs_root, 'doxygen')
    doxyfile_main = os.path.join(doxyfile_dir, 'Doxyfile_common')
    doxyfile_target = os.path.join(doxyfile_dir, 'Doxyfile_' + app.config.idf_target)
    print('Running doxygen with doxyfiles {} and {}'.format(doxyfile_main, doxyfile_target))

    # It's possible to have doxygen log warnings to a file using WARN_LOGFILE directive,
    # but in some cases it will still log an error to stderr and return success!
    #
    # So take all of stderr and redirect it to a logfile (will contain warnings and errors)
    logfile = os.path.join(build_dir, 'doxygen-warning-log.txt')

    with open(logfile, 'w') as f:
        # note: run Doxygen in the build directory, so the xml & xml_in files end up in there
        subprocess.check_call(['doxygen', doxyfile_main], env=doxy_env, cwd=build_dir, stderr=f)

    # Doxygen has generated XML files in 'xml' directory.
    # Copy them to 'xml_in', only touching the files which have changed.
    copy_if_modified(os.path.join(build_dir, 'xml/'), os.path.join(build_dir, 'xml_in/'))

    # Generate 'api_name.inc' files from the Doxygen XML files
    doxygen_paths = [doxyfile_main, doxyfile_target]
    convert_api_xml_to_inc(app, doxygen_paths)


def convert_api_xml_to_inc(app, doxyfiles):
    """ Generate header_file.inc files
    with API reference made of doxygen directives
    for each header file
    specified in the 'INPUT' statement of the Doxyfile.
    """
    build_dir = app.config.build_dir

    xml_directory_path = '{}/xml'.format(build_dir)
    inc_directory_path = '{}/inc'.format(build_dir)

    fast_build = os.environ.get('DOCS_FAST_BUILD', None)

    if not os.path.isdir(xml_directory_path):
        raise RuntimeError('Directory {} does not exist!'.format(xml_directory_path))

    if not os.path.exists(inc_directory_path):
        os.makedirs(inc_directory_path)

    header_paths = [p for d in doxyfiles for p in get_doxyfile_input_paths(app, d)]

    print("Generating 'api_name.inc' files with Doxygen directives")
    for header_file_path in header_paths:
        api_name = get_api_name(header_file_path)
        inc_file_path = inc_directory_path + '/' + api_name + '.inc'
        rst_output = generate_directives(header_file_path, xml_directory_path)

        previous_rst_output = ''
        if os.path.isfile(inc_file_path):
            with open(inc_file_path, 'r', encoding='utf-8') as inc_file_old:
                previous_rst_output = inc_file_old.read()

        if previous_rst_output != rst_output:
            with open(inc_file_path, 'w', encoding='utf-8') as inc_file:
                inc_file.write(rst_output)

        # For fast builds we wipe the doxygen api documention.
        # Parsing this output during the sphinx build process is
        # what takes 95% of the build time
        if fast_build:
            with open(inc_file_path, 'w', encoding='utf-8') as inc_file:
                inc_file.write('')


def get_doxyfile_input_paths(app, doxyfile_path):
    """Get contents of Doxyfile's INPUT statement.

    Returns:
        Contents of Doxyfile's INPUT.

    """
    if not os.path.isfile(doxyfile_path):
        raise RuntimeError("Doxyfile '{}' does not exist!".format(doxyfile_path))

    print("Getting Doxyfile's INPUT")

    with open(doxyfile_path, 'r', encoding='utf-8') as input_file:
        line = input_file.readline()
        # read contents of Doxyfile until 'INPUT' statement
        while line:
            if line.find('INPUT') == 0:
                break
            line = input_file.readline()

        doxyfile_INPUT = []
        line = input_file.readline()
        # skip input_file contents until end of 'INPUT' statement
        while line:
            if line.isspace():
                # we have reached the end of 'INPUT' statement
                break
            # process only lines that are not comments
            if line.find('#') == -1:
                # extract header file path inside components folder
                m = re.search('components/(.*\.h)', line)  # noqa: W605 - regular expression
                header_file_path = m.group(1)

                # Replace env variable used for multi target header
                header_file_path = header_file_path.replace('$(IDF_TARGET)', app.config.idf_target)

                doxyfile_INPUT.append(header_file_path)

            # proceed reading next line
            line = input_file.readline()

    return doxyfile_INPUT


def get_api_name(header_file_path):
    """Get name of API from header file path.

    Args:
        header_file_path: path to the header file.

    Returns:
        The name of API.

    """
    api_name = ''
    regex = r'.*/(.*)\.h'
    m = re.search(regex, header_file_path)
    if m:
        api_name = m.group(1)

    return api_name


def generate_directives(header_file_path, xml_directory_path):
    """Generate API reference with Doxygen directives for a header file.

    Args:
        header_file_path: a path to the header file with API.

    Returns:
        Doxygen directives for the header file.

    """

    api_name = get_api_name(header_file_path)

    # in XLT file name each "_" in the api name is expanded by Doxygen to "__"
    xlt_api_name = api_name.replace('_', '__')
    xml_file_path = '%s/%s_8h.xml' % (xml_directory_path, xlt_api_name)

    rst_output = ''
    rst_output = ".. File automatically generated by 'gen-dxd.py'\n"
    rst_output += '\n'
    rst_output += get_rst_header('Header File')
    rst_output += '* :component_file:`' + header_file_path + '`\n'
    rst_output += '\n'

    try:
        import xml.etree.cElementTree as ET
    except ImportError:
        import xml.etree.ElementTree as ET

    tree = ET.ElementTree(file=xml_file_path)
    for kind, label in ALL_KINDS:
        rst_output += get_directives(tree, kind)

    return rst_output


def get_rst_header(header_name):
    """Get rst formatted code with a header.

    Args:
        header_name: name of header.

    Returns:
        Formatted rst code with the header.

    """

    rst_output = ''
    rst_output += header_name + '\n'
    rst_output += '^' * len(header_name) + '\n'
    rst_output += '\n'

    return rst_output


def select_unions(innerclass_list):
    """Select unions from innerclass list.

    Args:
        innerclass_list: raw list with unions and structures
                         extracted from Dogygen's xml file.

    Returns:
        Doxygen directives with unions selected from the list.

    """

    rst_output = ''
    for line in innerclass_list.splitlines():
        # union is denoted by "union" at the beginning of line
        if line.find('union') == 0:
            union_id, union_name = re.split(r'\t+', line)
            rst_output += '.. doxygenunion:: '
            rst_output += union_name
            rst_output += '\n'

    return rst_output


def select_structs(innerclass_list):
    """Select structures from innerclass list.

    Args:
        innerclass_list: raw list with unions and structures
                         extracted from Dogygen's xml file.

    Returns:
        Doxygen directives with structures selected from the list.
        Note: some structures are excluded as described on code below.

    """

    rst_output = ''
    for line in innerclass_list.splitlines():
        # structure is denoted by "struct" at the beginning of line
        if line.find('struct') == 0:
            # skip structures that are part of union
            # they are documented by 'doxygenunion' directive
            if line.find('::') > 0:
                continue
            struct_id, struct_name = re.split(r'\t+', line)
            rst_output += '.. doxygenstruct:: '
            rst_output += struct_name
            rst_output += '\n'
            rst_output += '    :members:\n'
            rst_output += '\n'

    return rst_output


def get_directives(tree, kind):
    """Get directives for specific 'kind'.

    Args:
        tree: the ElementTree 'tree' of XML by Doxygen
        kind: name of API "kind" to be generated

    Returns:
        Doxygen directives for selected 'kind'.
        Note: the header with "kind" name is included.

    """

    rst_output = ''
    if kind in ['union', 'struct']:
        innerclass_list = ''
        for elem in tree.iterfind('compounddef/innerclass'):
            innerclass_list += elem.attrib['refid'] + '\t' + elem.text + '\n'
        if kind == 'union':
            rst_output += select_unions(innerclass_list)
        else:
            rst_output += select_structs(innerclass_list)
    else:
        for elem in tree.iterfind(
                'compounddef/sectiondef/memberdef[@kind="%s"]' % kind):
            name = elem.find('name')
            rst_output += '.. doxygen%s:: ' % kind
            rst_output += name.text + '\n'
    if rst_output:
        all_kinds_dict = dict(ALL_KINDS)
        rst_output = get_rst_header(all_kinds_dict[kind]) + rst_output + '\n'

    return rst_output