import markdown
import re
import os
import math
from textwrap import dedent
from functools import lru_cache
from pymdownx.superfences import fence_div_format, fence_code_format
from latex2mathml.converter import convert as tex2mathml
from shared_utils.config_loader import get_conf as get_conf

pj = os.path.join
default_user_name = 'default_user'

markdown_extension_configs = {
    'mdx_math': {
        'enable_dollar_delimiter': True,
        'use_gitlab_delimiters': False,
    },
}

code_highlight_configs = {
    "pymdownx.superfences": {
        'css_class': 'codehilite',
        "custom_fences": [
            {
                'name': 'mermaid',
                'class': 'mermaid',
                'format': fence_code_format
            }
        ]
    },
    "pymdownx.highlight": {
        'css_class': 'codehilite',
        'guess_lang': True,
        # 'auto_title': True,
        # 'linenums': True
    }
}

def text_divide_paragraph(text):
    """
    将文本按照段落分隔符分割开，生成带有段落标签的HTML代码。
    """
    pre = '<div class="markdown-body">'
    suf = '</div>'
    if text.startswith(pre) and text.endswith(suf):
        return text

    if '```' in text:
        # careful input
        return text
    elif '</div>' in text:
        # careful input
        return text
    else:
        # whatever input
        lines = text.split("\n")
        for i, line in enumerate(lines):
            lines[i] = lines[i].replace(" ", "&nbsp;")
        text = "</br>".join(lines)
        return pre + text + suf


def tex2mathml_catch_exception(content, *args, **kwargs):
    try:
        content = tex2mathml(content, *args, **kwargs)
    except:
        content = content
    return content


def replace_math_no_render(match):
    content = match.group(1)
    if 'mode=display' in match.group(0):
        content = content.replace('\n', '</br>')
        return f"<font color=\"#00FF00\">$$</font><font color=\"#FF00FF\">{content}</font><font color=\"#00FF00\">$$</font>"
    else:
        return f"<font color=\"#00FF00\">$</font><font color=\"#FF00FF\">{content}</font><font color=\"#00FF00\">$</font>"


def replace_math_render(match):
    content = match.group(1)
    if 'mode=display' in match.group(0):
        if '\\begin{aligned}' in content:
            content = content.replace('\\begin{aligned}', '\\begin{array}')
            content = content.replace('\\end{aligned}', '\\end{array}')
            content = content.replace('&', ' ')
        content = tex2mathml_catch_exception(content, display="block")
        return content
    else:
        return tex2mathml_catch_exception(content)


def markdown_bug_hunt(content):
    """
    解决一个mdx_math的bug（单$包裹begin命令时多余<script>）
    """
    content = content.replace('<script type="math/tex">\n<script type="math/tex; mode=display">',
                                '<script type="math/tex; mode=display">')
    content = content.replace('</script>\n</script>', '</script>')
    return content


def is_equation(txt):
    """
    判定是否为公式 | 测试1 写出洛伦兹定律，使用tex格式公式 测试2 给出柯西不等式，使用latex格式 测试3 写出麦克斯韦方程组
    """
    if '```' in txt and '```reference' not in txt: return False
    if '$' not in txt and '\\[' not in txt: return False
    mathpatterns = {
        r'(?<!\\|\$)(\$)([^\$]+)(\$)': {'allow_multi_lines': False},                       #  $...$
        r'(?<!\\)(\$\$)([^\$]+)(\$\$)': {'allow_multi_lines': True},                       # $$...$$
        r'(?<!\\)(\\\[)(.+?)(\\\])': {'allow_multi_lines': False},                         # \[...\]
        # r'(?<!\\)(\\\()(.+?)(\\\))': {'allow_multi_lines': False},                       # \(...\)
        # r'(?<!\\)(\\begin{([a-z]+?\*?)})(.+?)(\\end{\2})': {'allow_multi_lines': True},  # \begin...\end
        # r'(?<!\\)(\$`)([^`]+)(`\$)': {'allow_multi_lines': False},                       # $`...`$
    }
    matches = []
    for pattern, property in mathpatterns.items():
        flags = re.ASCII | re.DOTALL if property['allow_multi_lines'] else re.ASCII
        matches.extend(re.findall(pattern, txt, flags))
    if len(matches) == 0: return False
    contain_any_eq = False
    illegal_pattern = re.compile(r'[^\x00-\x7F]|echo')
    for match in matches:
        if len(match) != 3: return False
        eq_canidate = match[1]
        if illegal_pattern.search(eq_canidate):
            return False
        else:
            contain_any_eq = True
    return contain_any_eq


def fix_markdown_indent(txt):
    # fix markdown indent
    if (' - ' not in txt) or ('. ' not in txt):
        # do not need to fix, fast escape
        return txt
    # walk through the lines and fix non-standard indentation
    lines = txt.split("\n")
    pattern = re.compile(r'^\s+-')
    activated = False
    for i, line in enumerate(lines):
        if line.startswith('- ') or line.startswith('1. '):
            activated = True
        if activated and pattern.match(line):
            stripped_string = line.lstrip()
            num_spaces = len(line) - len(stripped_string)
            if (num_spaces % 4) == 3:
                num_spaces_should_be = math.ceil(num_spaces / 4) * 4
                lines[i] = ' ' * num_spaces_should_be + stripped_string
    return '\n'.join(lines)


FENCED_BLOCK_RE = re.compile(
    dedent(r'''
        (?P<fence>^[ \t]*(?:~{3,}|`{3,}))[ ]*                      # opening fence
        ((\{(?P<attrs>[^\}\n]*)\})|                              # (optional {attrs} or
        (\.?(?P<lang>[\w#.+-]*)[ ]*)?                            # optional (.)lang
        (hl_lines=(?P<quot>"|')(?P<hl_lines>.*?)(?P=quot)[ ]*)?) # optional hl_lines)
        \n                                                       # newline (end of opening fence)
        (?P<code>.*?)(?<=\n)                                     # the code block
        (?P=fence)[ ]*$                                          # closing fence
    '''),
    re.MULTILINE | re.DOTALL | re.VERBOSE
)


def get_line_range(re_match_obj, txt):
    start_pos, end_pos = re_match_obj.regs[0]
    num_newlines_before = txt[:start_pos+1].count('\n')
    line_start = num_newlines_before
    line_end = num_newlines_before + txt[start_pos:end_pos].count('\n')+1
    return line_start, line_end


def fix_code_segment_indent(txt):
    lines = []
    change_any = False
    txt_tmp = txt
    while True:
        re_match_obj = FENCED_BLOCK_RE.search(txt_tmp)
        if not re_match_obj: break
        if len(lines) == 0: lines = txt.split("\n")
        
        # 清空 txt_tmp 对应的位置方便下次搜索
        start_pos, end_pos = re_match_obj.regs[0]
        txt_tmp = txt_tmp[:start_pos] + ' '*(end_pos-start_pos) + txt_tmp[end_pos:]
        line_start, line_end = get_line_range(re_match_obj, txt)
        
        # 获取公共缩进
        shared_indent_cnt = 1e5
        for i in range(line_start, line_end):
            stripped_string = lines[i].lstrip()
            num_spaces = len(lines[i]) - len(stripped_string)
            if num_spaces < shared_indent_cnt:
                shared_indent_cnt = num_spaces

        # 修复缩进
        if (shared_indent_cnt < 1e5) and (shared_indent_cnt % 4) == 3:
            num_spaces_should_be = math.ceil(shared_indent_cnt / 4) * 4
            for i in range(line_start, line_end):
                add_n = num_spaces_should_be - shared_indent_cnt
                lines[i] = ' ' * add_n + lines[i]
            if not change_any: # 遇到第一个
                change_any = True

    if change_any:
        return '\n'.join(lines)
    else:
        return txt
    
    
@lru_cache(maxsize=128) # 使用 lru缓存 加快转换速度
def markdown_convertion(txt):
    """
    将Markdown格式的文本转换为HTML格式。如果包含数学公式，则先将公式转换为HTML格式。
    """
    pre = '<div class="markdown-body">'
    suf = '</div>'
    if txt.startswith(pre) and txt.endswith(suf):
        # print('警告，输入了已经经过转化的字符串，二次转化可能出问题')
        return txt # 已经被转化过，不需要再次转化

    find_equation_pattern = r'<script type="math/tex(?:.*?)>(.*?)</script>'

    txt = fix_markdown_indent(txt)
    # txt = fix_code_segment_indent(txt)
    if is_equation(txt):  # 有$标识的公式符号，且没有代码段```的标识
        # convert everything to html format
        split = markdown.markdown(text='---')
        convert_stage_1 = markdown.markdown(text=txt, extensions=['sane_lists', 'tables', 'mdx_math', 'pymdownx.superfences', 'pymdownx.highlight'],
                                            extension_configs={**markdown_extension_configs, **code_highlight_configs})
        convert_stage_1 = markdown_bug_hunt(convert_stage_1)
        # 1. convert to easy-to-copy tex (do not render math)
        convert_stage_2_1, n = re.subn(find_equation_pattern, replace_math_no_render, convert_stage_1, flags=re.DOTALL)
        # 2. convert to rendered equation
        convert_stage_2_2, n = re.subn(find_equation_pattern, replace_math_render, convert_stage_1, flags=re.DOTALL)
        # cat them together
        return pre + convert_stage_2_1 + f'{split}' + convert_stage_2_2 + suf
    else:
        return pre + markdown.markdown(txt, extensions=['sane_lists', 'tables', 'pymdownx.superfences', 'pymdownx.highlight'], extension_configs=code_highlight_configs) + suf


def close_up_code_segment_during_stream(gpt_reply):
    """
    在gpt输出代码的中途（输出了前面的```，但还没输出完后面的```），补上后面的```

    Args:
        gpt_reply (str): GPT模型返回的回复字符串。

    Returns:
        str: 返回一个新的字符串，将输出代码片段的“后面的```”补上。

    """
    if '```' not in gpt_reply:
        return gpt_reply
    if gpt_reply.endswith('```'):
        return gpt_reply

    # 排除了以上两个情况，我们
    segments = gpt_reply.split('```')
    n_mark = len(segments) - 1
    if n_mark % 2 == 1:
        return gpt_reply + '\n```' # 输出代码片段中！
    else:
        return gpt_reply


def format_io(self, y):
    """
    将输入和输出解析为HTML格式。将y中最后一项的输入部分段落化，并将输出部分的Markdown和数学公式转换为HTML格式。
    """
    if y is None or y == []:
        return []
    i_ask, gpt_reply = y[-1]
    # 输入部分太自由，预处理一波
    if i_ask is not None: i_ask = text_divide_paragraph(i_ask)
    # 当代码输出半截的时候，试着补上后个```
    if gpt_reply is not None: gpt_reply = close_up_code_segment_during_stream(gpt_reply)
    # process
    y[-1] = (
        None if i_ask is None else markdown.markdown(i_ask, extensions=['pymdownx.superfences', 'tables', 'pymdownx.highlight'], extension_configs=code_highlight_configs),
        None if gpt_reply is None else markdown_convertion(gpt_reply)
    )
    return y
