#!/usr/bin/env python3
"""Markdown to Feishu Docx Block JSON converter (state-machine based).

Usage: python3 md_to_blocks.py < input.md > output.json
       python3 md_to_blocks.py file.md

Design:
- Block-level state machine: scans line by line, each line starts a block state
  (heading / bullet / ordered / quote / code / table / divider / paragraph).
- Inline state machine: scans character by character with an explicit state
  stack so that nested inline markers (e.g. bold-wrapped links) resolve
  correctly. Inside bold/italic we recursively re-enter the inline machine,
  then merge the wrapper style onto every produced text_run.
- Table blocks (31) are emitted as nested structures with cell blocks (32).
"""

import re, json, sys

TABLE_BLOCK = 31
CELL_BLOCK = 32
TEXT_BLOCK = 2
CODE_BLOCK = 14
PREFIX = 'ecc_'

# 全局表格计数器：每个表格用唯一 ID 前缀，避免多表格时 block_id 冲突
_table_counter = 0

LANG_CODES = {
    '': 1, 'text': 1, 'plain': 1,
    'bash': 7, 'sh': 7, 'shell': 7,
    'python': 11, 'py': 11,
    'go': 5, 'golang': 5,
    'js': 12, 'javascript': 12, 'json': 14,
    'yaml': 33, 'yml': 33,
    'sql': 25,
}

def lang_code(lang):
    """Map markdown code fence language to Feishu code block language id."""
    return LANG_CODES.get(lang.lower(), 1)


# --------------------------------------------------------------------------
# Inline state machine
# --------------------------------------------------------------------------
# States of the inline scanner.
ST_TEXT = 'TEXT'          # plain text / default
ST_LINK_TEXT = 'LINK_TEXT'  # inside [ ... ] of a link
ST_LINK_URL = 'LINK_URL'  # inside ( ... ) of a link

_INLINE_OPENER = re.compile(r'\*\*|__|\*|`|\[')
_INLINE_TOKENS = {
    '**': 'bold',
    '__': 'bold',
    '`': 'code',
}


def _merge_style(elements, style):
    """Apply a wrapper style (bold/italic/code) to every produced text_run."""
    for el in elements:
        if 'text_run' in el:
            el['text_run']['text_element_style'].update(style)
    return elements


def scan_inline(text):
    """Inline state machine -> list of text_run elements.

    Handles nesting by recursion: when we hit a bold/italic/code opener we
    recurse into the inner span, then merge the wrapper style onto the result.
    Links are handled with an explicit two-phase state (LINK_TEXT then
    LINK_URL), so `[title](url)` never leaks raw markdown.
    """
    elements = []
    pos = 0
    n = len(text)

    def emit(content, style):
        if content:
            elements.append({'text_run': {'content': content,
                                          'text_element_style': style}})

    while pos < n:
        ch = text[pos]

        # --- opener: bold ---
        if text.startswith('**', pos) or text.startswith('__', pos):
            width = 2
            opener = text[pos:pos + width]
            end = text.find(opener, pos + width)
            if end != -1:
                inner = scan_inline(text[pos + width:end])
                _merge_style(inner, {'bold': True})
                elements.extend(inner)
                pos = end + width
                continue
            # unmatched -> literal
            emit(opener, {})
            pos += width
            continue

        # --- opener: single-star italic ---
        if ch == '*':
            end = text.find('*', pos + 1)
            if end != -1 and not text.startswith('**', pos):
                inner = scan_inline(text[pos + 1:end])
                _merge_style(inner, {'italic': True})
                elements.extend(inner)
                pos = end + 1
                continue
            emit('*', {})
            pos += 1
            continue

        # --- opener: inline code ---
        if ch == '`':
            end = text.find('`', pos + 1)
            if end != -1:
                emit(text[pos + 1:end], {'inline_code': True})
                pos = end + 1
                continue
            emit('`', {})
            pos += 1
            continue

        # --- link: [text](url) via two-phase state machine ---
        if ch == '[':
            # collect link text until matching ']'
            i = pos + 1
            depth = 1
            txt = []
            while i < n and depth > 0:
                if text[i] == '[':
                    depth += 1
                elif text[i] == ']':
                    depth -= 1
                    if depth == 0:
                        break
                txt.append(text[i])
                i += 1
            if depth == 0 and i + 1 < n and text[i + 1] == '(':
                # collect url until matching ')'
                j = i + 2
                url_end = text.find(')', j)
                if url_end != -1:
                    url = text[j:url_end]
                    link_text = ''.join(txt)
                    elements.append({'text_run': {
                        'content': link_text,
                        'text_element_style': {'link': {'url': url}},
                    }})
                    pos = url_end + 1
                    continue
            # not a valid link -> literal '['
            emit('[', {})
            pos += 1
            continue

        # --- plain text until next inline opener ---
        m = _INLINE_OPENER.search(text, pos)
        if m:
            end = m.start()
            if end > pos:
                emit(text[pos:end], {})
            pos = end
        else:
            emit(text[pos:], {})
            break

    return elements


# --------------------------------------------------------------------------
# Table helpers (kept from original, table block-level parsing)
# --------------------------------------------------------------------------
def is_sep_line(line):
    s = line.strip()
    if not s.startswith('|') or not s.endswith('|'):
        return False
    parts = s[1:-1].split('|')
    return all(re.match(r'^[\s\-:]+$', p) for p in parts)


def is_table_row(line):
    s = line.strip()
    return s.startswith('|') and s.endswith('|') and '|' in s[1:-1]


def split_row(line):
    return [c.strip() for c in line.strip()[1:-1].split('|')]


def parse_table(lines, start_idx):
    global _table_counter
    i = start_idx
    headers = []
    has_header = False

    if i >= len(lines) or not is_table_row(lines[i]):
        return None, start_idx

    first_cells = split_row(lines[i])
    if not first_cells:
        return None, start_idx

    i += 1
    if i < len(lines) and is_sep_line(lines[i]):
        headers = first_cells
        has_header = True
        i += 1

    data_rows = []
    while i < len(lines) and is_table_row(lines[i]):
        row = split_row(lines[i])
        if row:
            data_rows.append(row)
        i += 1

    if has_header:
        data_rows.insert(0, headers)
    else:
        data_rows.insert(0, first_cells)

    if not data_rows:
        return None, start_idx

    num_rows = len(data_rows)
    num_cols = max(len(r) for r in data_rows)

    blocks = []
    table_id = f'{PREFIX}t{_table_counter}'
    _table_counter += 1
    cell_ids = []

    table_block = {
        'block_id': table_id,
        'block_type': TABLE_BLOCK,
        'table': {
            'property': {
                'row_size': num_rows,
                'column_size': num_cols,
                'header_row': has_header
            }
        },
        'children': [],
        '__table': True,
        '__rows': num_rows,
        '__cols': num_cols
    }

    for row_idx, row in enumerate(data_rows):
        for col_idx in range(num_cols):
            cell_text = row[col_idx] if col_idx < len(row) else ''
            cell_id = f'{table_id}r{row_idx}c{col_idx}'
            text_id = f'{table_id}r{row_idx}c{col_idx}t'
            cell_ids.append(cell_id)

            is_header_cell = has_header and row_idx == 0
            elements = scan_inline(cell_text)
            if not elements:
                elements = [{'text_run': {'content': cell_text, 'text_element_style': {}}}]
            if is_header_cell:
                for el in elements:
                    if 'text_run' in el:
                        el['text_run']['text_element_style']['bold'] = True

            text_block = {
                'block_id': text_id,
                'block_type': TEXT_BLOCK,
                'text': {'elements': elements, 'style': {}},
                'children': []
            }
            cell_block = {
                'block_id': cell_id,
                'block_type': CELL_BLOCK,
                'table_cell': {},
                'children': [text_id]
            }

            table_block['children'].append(cell_id)
            blocks.append(cell_block)
            blocks.append(text_block)

    blocks.insert(0, table_block)
    return blocks, i


# --------------------------------------------------------------------------
# Block-level state machine (line-by-line)
# --------------------------------------------------------------------------
def md_to_blocks(md_text):
    """Convert Markdown text to Feishu Block JSON array."""
    lines = md_text.strip().split('\n')
    blocks = []
    i = 0
    while i < len(lines):
        line = lines[i]

        # Fenced code block: ```lang ... ```
        fence = re.match(r'^```(\w*)\s*$', line.strip())
        if fence:
            lang = fence.group(1)
            code_lines = []
            i += 1
            while i < len(lines) and not lines[i].strip().startswith('```'):
                code_lines.append(lines[i])
                i += 1
            i += 1  # skip closing fence
            code_text = '\n'.join(code_lines)
            blocks.append({
                'block_type': CODE_BLOCK,
                'code': {
                    'elements': [{'text_run': {'content': code_text, 'text_element_style': {}}}],
                    'style': {'language': lang_code(lang)}
                }
            })
            continue

        # Empty line
        if not line.strip():
            if i + 1 < len(lines) and lines[i + 1].strip() and not lines[i + 1].strip().startswith(('#', '-', '*', '`', '---', '|')):
                blocks.append({'block_type': 2, 'text': {'elements': [{'text_run': {'content': '', 'text_element_style': {}}}], 'style': {}}})
            i += 1
            continue

        # Divider
        if line.strip() in ('---', '***'):
            blocks.append({'block_type': 22, 'divider': {}})
            i += 1
            continue

        # Table detection
        if '|' in line:
            tbl, ni = parse_table(lines, i)
            if tbl is not None:
                blocks.extend(tbl)
                i = ni
                continue

        # Headings
        h = re.match(r'^(#{1,3})\s+(.+)$', line)
        if h:
            level = len(h.group(1))
            bt = 2 + level
            blocks.append({
                'block_type': bt,
                f'heading{level}': {
                    'elements': scan_inline(h.group(2)),
                    'style': {}
                }
            })
            i += 1
            continue

        # Quote
        quote = re.match(r'^>\s?(.+)$', line)
        if quote:
            blocks.append({
                'block_type': 15,
                'quote': {
                    'elements': scan_inline(quote.group(1)),
                    'style': {}
                }
            })
            i += 1
            continue

        # Bullet list
        bullet = re.match(r'^[\-\*]\s+(.+)$', line)
        if bullet:
            blocks.append({
                'block_type': 12,
                'bullet': {
                    'elements': scan_inline(bullet.group(1)),
                    'style': {}
                }
            })
            i += 1
            continue

        # Numbered list
        numbered = re.match(r'^\d+\.\s+(.+)$', line)
        if numbered:
            blocks.append({
                'block_type': 13,
                'ordered': {
                    'elements': scan_inline(numbered.group(1)),
                    'style': {}
                }
            })
            i += 1
            continue

        # Regular text (paragraph)
        elements = scan_inline(line)
        blocks.append({
            'block_type': 2,
            'text': {
                'elements': elements if elements else [{'text_run': {'content': line, 'text_element_style': {}}}],
                'style': {}
            }
        })
        i += 1

    return blocks


if __name__ == '__main__':
    if len(sys.argv) > 1:
        with open(sys.argv[1]) as f:
            text = f.read()
    else:
        text = sys.stdin.read()

    blocks = md_to_blocks(text)
    print(json.dumps(blocks, indent=2, ensure_ascii=False))