# Copyright (C) 2024 Carlos Maniero<carlos@maniero.me>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
import sys
import re

re_hl_block = r'<!--syntax:(?P<lang>\w+)( (?P<class>.*?))?-->.*?<pre class="verbatim">(?P<code>.*?)<\/pre>'

lexers = {
    'default': [
        (r'^(?P<value> +)', None),
        (r'^(?P<value>\d+)', 'num'),
        (r'^(?P<value>\w+)', 'ident'),
        (r'^(?P<value>\(|\)|{|})', 'brac'),
        (r'^(?P<value>&\w+;|\^|\~|!|@|\#|\$|%|&|\*|-|\+|\.|=|,|:|;|\||\\|/|\?)', 'symbol'),
        (r'^(?P<value>.+)', None),
    ],
    'olang': [
        (r'^(?P<value>#.*)', 'comment'),
        (r'^(?P<value>\w+) *?\(', 'fn-name'),
        (r'^(?P<value>fn|if|else|return|while|var|const|extern)', 'key'),
        (r'^\b(?P<value>u8|u16|u32|u64)\b', 'type'),
    ],
    'c': [
        (r'^(?P<value>#.*)', 'macro'),
        (r'^(?P<value>&quot;.*?&quot;)', 'str'),
        (r'^(?P<value>//.*)', 'comment'),
        (r'^(?P<value>\w+) *?\(', 'fn-name'),
        (r'^(?P<value>fn|if|else|return|while|var|const|extern)', 'key'),
        (r'^\b(?P<value>int|long|float)\b', 'type'),
    ],
    'bash': [
        (r'^(?P<value>-+.+? ?)', 'opt'),
        (r'^(?P<value>[A-z0\d\.-/]+)', 'ident'),
    ],
    'output': [
        (r'(?P<value>.*)', None),
    ],
    'ebnf': [
        (r'^(?P<value>.+?::=)', 'fn-name'),
        (r'^(?P<value>\|)', 'fn-name'),
        (r'^(?P<value>\?|\*)', 'key'),
        (r'^(?P<value>\(\*.*?\*\))', 'comment'),
        (r'^(?P<value>\'.*?\')', 'str'),
    ]
}

def format_code_line(line, lang):
    new_line = ''

    lexer = lexers.get(lang, []) + lexers['default']

    while line != '':
        for (regex, name) in lexer:
            match = re.match(regex, line)
            if match:
                value = match.group('value')
                line = line[len(value):]
                if name:
                    new_line += f'<span class="code-{name}">{value}</span>'
                else:
                    new_line += value
                break


    return f'<span class="code-line">{new_line}</span>'

def format_pre(match):
    lang = match.group('lang')
    css_class = match.group('class')
    css_classes = f'code-hl lang-{lang} {css_class or ""}'.strip()
    raw_lines = match.group('code').split('\n')

    while raw_lines[-1].strip() == '':
        raw_lines = raw_lines[:-1]

    code = "\n".join([format_code_line(line, lang) for line in raw_lines])

    return f'<pre class="{css_classes}">{code}</pre>'

def codehl(code):
    return re.sub(re_hl_block, format_pre, code, flags=re.DOTALL)

if __name__ == '__main__':
    for file_name in sys.argv[1:]:
        print(f"HL\t{file_name}")

        with open(file_name, 'r+') as file:
            content = codehl(file.read())

            file.seek(0)
            file.write(content)
            file.truncate()