#!/usr/bin/env python3
"""Minimal Plan F3 validator."""
from __future__ import annotations

import re
from pathlib import Path

REQUIRED_SECTIONS = ["purpose", "problem", "solution", "files", "phases", "validation", "references", "notes"]
REQUIRED_FRONTMATTER = ["product_id", "purpose", "references"]


def parse_frontmatter(text: str) -> dict:
    if not text.startswith("---\n"):
        return {}
    end = text.find("\n---", 4)
    if end == -1:
        return {}
    data = {}
    for line in text[4:end].splitlines():
        if ":" in line and not line.startswith(" "):
            key, value = line.split(":", 1)
            data[key.strip()] = value.strip()
    return data


def sections(text: str) -> set[str]:
    found = set()
    for match in re.finditer(r"^##\s+(.+)$", text, re.MULTILINE):
        found.add(match.group(1).strip().lower())
    return found


def validate_plan(path: str | Path, strict: bool = False) -> dict:
    path = Path(path)
    text = path.read_text(encoding="utf-8")
    front = parse_frontmatter(text)
    missing_front = [k for k in REQUIRED_FRONTMATTER if k not in front]
    found_sections = sections(text)
    missing_sections = [s for s in REQUIRED_SECTIONS if s not in found_sections]
    references_ok = "references" in front and bool(re.search(r"^## References\n- ", text, re.MULTILINE))
    html_path = path.with_suffix(".html")
    errors = []
    if missing_front:
        errors.append(f"missing frontmatter: {', '.join(missing_front)}")
    if missing_sections:
        errors.append(f"missing sections: {', '.join(missing_sections)}")
    if strict and not references_ok:
        errors.append("references missing or empty")
    if strict and not html_path.exists():
        errors.append("html plan missing")
    return {"ok": not errors, "errors": errors, "frontmatter": front, "html": str(html_path)}


if __name__ == "__main__":
    import json, sys
    print(json.dumps(validate_plan(sys.argv[1], "--strict" in sys.argv), indent=2))