Mermaid To Gif

#!/usr/bin/env python3
"""
mermaid_to_gif.py - Convert Mermaid diagrams to animated GIFs.

Pipeline: Mermaid code -> HTML with animation -> Playwright frame capture -> FFmpeg GIF

Usage:
    python mermaid_to_gif.py diagram.mmd
    python mermaid_to_gif.py document.md --style progressive
    python mermaid_to_gif.py document.md -o ./gifs/ --fps 12 --duration 5
"""

from __future__ import annotations

import argparse
import html as html_lib
import os
import re
import shutil
import subprocess
import sys
import tempfile
from pathlib import Path


# ============================================================
# Constants
# ============================================================

MERMAID_CDN = "https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.min.js"

STYLES = ["progressive", "highlight-walk", "pulse-flow", "wave"]
DEFAULT_STYLE = "progressive"
DEFAULT_FPS = 10
DEFAULT_DURATION = 4.0
DEFAULT_HOLD = 1.0
DEFAULT_BG = "#ffffff"
DEFAULT_THEME = "default"
DEFAULT_PADDING = 40
DEFAULT_SCALE = 2


# ============================================================
# Dependency checks
# ============================================================


def check_dependencies():
    """Verify required external tools are available."""
    errors = []
    if not shutil.which("ffmpeg"):
        errors.append(
            "FFmpeg is not installed.\n"
            "  macOS:   brew install ffmpeg\n"
            "  Ubuntu:  sudo apt install ffmpeg"
        )
    try:
        import playwright  # noqa: F401
    except ImportError:
        errors.append(
            "Playwright is not installed.\n"
            "  pip install playwright\n"
            "  playwright install chromium"
        )
    if errors:
        for e in errors:
            print(f"Error: {e}", file=sys.stderr)
        sys.exit(1)


# ============================================================
# Input parsing
# ============================================================


def extract_mermaid_blocks(text: str) -> list[str]:
    """Extract ```mermaid code blocks from markdown text."""
    pattern = r"```mermaid\s*\n(.*?)```"
    return [m.strip() for m in re.findall(pattern, text, re.DOTALL)]


def read_input(path: str) -> list[tuple[str, str]]:
    """Read input file and return list of (name, mermaid_code) tuples."""
    p = Path(path)
    if not p.exists():
        print(f"Error: {path} does not exist", file=sys.stderr)
        sys.exit(1)

    text = p.read_text(encoding="utf-8")

    if p.suffix == ".mmd":
        return [(p.stem, text.strip())]

    # Markdown or other text file - extract mermaid blocks
    blocks = extract_mermaid_blocks(text)
    if not blocks:
        print(f"No mermaid code blocks found in {path}", file=sys.stderr)
        return []

    if len(blocks) == 1:
        return [(p.stem, blocks[0])]
    return [(f"{p.stem}-{i + 1}", block) for i, block in enumerate(blocks)]


def detect_direction(mermaid_code: str) -> str:
    """Detect diagram flow direction from mermaid source code."""
    first_line = mermaid_code.strip().split("\n")[0].lower()
    if any(d in first_line for d in ["lr", "rl"]):
        return "horizontal"
    return "vertical"


# ============================================================
# Animation JS - shared element collection logic
# ============================================================

ELEMENT_COLLECTION_JS = """
    // Collect elements by type separately for better animation control
    var clusters = [];
    var nodes = [];
    var edges = [];
    var edgeLabels = [];
    var direction = '{direction}';

    var sortFn = direction === 'horizontal'
        ? function(a, b) { return (a.x - b.x) || (a.y - b.y); }
        : function(a, b) { return (a.y - b.y) || (a.x - b.x); };

    svg.querySelectorAll('.cluster').forEach(function(el) {
        var rect = el.getBoundingClientRect();
        clusters.push({ el: el, x: rect.x, y: rect.y });
    });

    svg.querySelectorAll('.node, .actor, [class*="note"]').forEach(function(el) {