#!/usr/bin/env python3 """Prepare a local Markdown draft for Substack import. This helper intentionally avoids Substack authentication. It creates a publish bundle that can be pasted/imported into the Substack editor. """ from __future__ import annotations import argparse import html import json import re import shutil from pathlib import Path IMAGE_RE = re.compile(r"^\[IMAGE:\s*(?P[^\]]+?)\s*\]\s*$") def slugify_title(text: str) -> str: text = text.strip().lower() text = re.sub(r"[^a-z0-9]+", "-", text) return text.strip("-") or "substack-post" def render_inline(markdown: str) -> str: """Render the small inline Markdown subset used by the preview.""" placeholders: list[str] = [] def stash(value: str) -> str: placeholders.append(value) return f"\x00{len(placeholders) - 1}\x00" text = html.escape(markdown) text = re.sub(r"`([^`]+)`", lambda m: stash(f"{m.group(1)}"), text) text = re.sub( r"\[([^\]]+)\]\(([^)]+)\)", lambda m: stash(f"{m.group(1)}"), text, ) text = re.sub(r"\*\*([^*]+)\*\*", r"\1", text) text = re.sub(r"(?\1", text) for idx, value in enumerate(placeholders): text = text.replace(f"\x00{idx}\x00", value) return text def markdown_to_basic_html(markdown: str) -> str: """Small preview renderer, not a full Markdown implementation.""" lines = markdown.splitlines() out: list[str] = [] in_code = False para: list[str] = [] list_items: list[str] = [] def flush_para() -> None: if para: out.append(f"

{render_inline(' '.join(para))}

") para.clear() def flush_list() -> None: if list_items: out.append("") list_items.clear() for line in lines: if line.startswith("```"): flush_para() flush_list() if in_code: out.append("") in_code = False else: out.append("
")
                in_code = True
            continue
        if in_code:
            out.append(html.escape(line))
            continue
        if not line.strip():
            flush_para()
            flush_list()
            continue
        if re.match(r"^(-{3,}|\*{3,}|_{3,})\s*$", line.strip()):
            flush_para()
            flush_list()
            out.append("
")
            continue
        if line.startswith("# "):
            flush_para()
            flush_list()
            out.append(f"
{render_inline(line[2:].strip())}
")
        elif line.startswith("## "):
            flush_para()
            flush_list()
            out.append(f"
{render_inline(line[3:].strip())}
")
        elif line.startswith("### "):
            flush_para()
            flush_list()
            out.append(f"
{render_inline(line[4:].strip())}
")
        elif line.startswith("> "):
            flush_para()
            flush_list()
            out.append(f"
{render_inline(line[2:].strip())}
")
        elif line.startswith("- "):
            flush_para()
            list_items.append(line[2:].strip())
        elif line.startswith("!["):
            flush_para()
            flush_list()
            match = re.match(r"!\[(?P[^\]]*)\]\((?P[^)]+)\)", line)
            if match:
                out.append(
                    f"
"
                )
            else:
                para.append(line)
        else:
            flush_list()
            para.append(line)
    flush_para()
    flush_list()
    if in_code:
        out.append("
") return "\n\n" + "\n".join(out) + "\n" def prepare(markdown_path: Path, output_dir: Path | None = None) -> dict: markdown_path = markdown_path.resolve() source_dir = markdown_path.parent raw = markdown_path.read_text(encoding="utf-8") title = next((line[2:].strip() for line in raw.splitlines() if line.startswith("# ")), markdown_path.stem) subtitle = next((line[3:].strip() for line in raw.splitlines() if line.startswith("## ")), "") bundle_dir = (output_dir or source_dir / "substack_bundle").resolve() assets_dir = bundle_dir / "assets" assets_dir.mkdir(parents=True, exist_ok=True) converted: list[str] = [] copied_assets: list[str] = [] missing_assets: list[str] = [] for line in raw.splitlines(): match = IMAGE_RE.match(line) if not match: converted.append(line) continue name = match.group("name").strip() src = (source_dir / name).resolve() if src.exists() and src.is_file(): dest = assets_dir / src.name shutil.copy2(src, dest) copied_assets.append(str(dest)) converted.append(f"![{src.stem.replace('_', ' ')}](assets/{src.name})") else: missing_assets.append(name) converted.append(f"") post_md = bundle_dir / "post.md" post_html = bundle_dir / "post.html" manifest = bundle_dir / "manifest.json" converted_text = "\n".join(converted).rstrip() + "\n" post_md.write_text(converted_text, encoding="utf-8") post_html.write_text(markdown_to_basic_html(converted_text), encoding="utf-8") data = { "title": title, "subtitle": subtitle, "slug": slugify_title(title), "source": str(markdown_path), "bundle_dir": str(bundle_dir), "post_md": str(post_md), "post_html": str(post_html), "copied_assets": copied_assets, "missing_assets": missing_assets, } manifest.write_text(json.dumps(data, indent=2) + "\n", encoding="utf-8") return data def main() -> int: parser = argparse.ArgumentParser(description="Prepare a Markdown draft for Substack.") parser.add_argument("markdown_path", type=Path) parser.add_argument("--output-dir", type=Path) args = parser.parse_args() print(json.dumps(prepare(args.markdown_path, args.output_dir), indent=2)) return 0 if __name__ == "__main__": raise SystemExit(main())