#!/usr/bin/env python3
"""Compact generated continuation documents when their context budgets overflow."""
from __future__ import annotations

import json
import re
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
BUDGET = ROOT / "docs/current/FREECAD_WEB_CONTEXT_BUDGET.json"
HANDOFF = ROOT / "docs/current/FREECAD_WEB_HANDOFF.md"
TASKS = ROOT / "docs/tasks/p6/full-parity"


def fit(text: str, limit: int) -> str:
    raw = text.encode("utf-8")
    if len(raw) <= limit:
        return text
    return raw[: max(0, limit - 40)].decode("utf-8", "ignore").rstrip() + "\n"


def compact_handoff(limit: int) -> bool:
    if HANDOFF.stat().st_size <= limit:
        return False
    text = HANDOFF.read_text(encoding="utf-8", errors="replace")
    marker = "## 本回合检查点"
    prefix = text.split(marker, 1)[0].rstrip()
    checkpoint = text.split(marker, 1)[1] if marker in text else ""
    bullets = [line.strip() for line in checkpoint.splitlines() if line.strip().startswith("-")]
    # Keep only the latest checkpoint facts; table fields and the automatic
    # continuation entry remain authoritative and are preserved in prefix.
    latest = bullets[-5:]
    compact = prefix + "\n\n## 本回合检查点（压缩）\n" + "\n".join(latest) + "\n"
    HANDOFF.write_text(fit(compact, limit), encoding="utf-8")
    return True


def compact_card(path: Path, limit: int) -> bool:
    if path.stat().st_size <= limit:
        return False
    text = path.read_text(encoding="utf-8", errors="replace")
    sections = re.split(r"(?m)(?=^## )", text)
    header = sections[0].rstrip()
    result = [section for section in sections[1:] if section.startswith("## 结果") or section.startswith("## 当前结果")]
    recovery = [section for section in sections[1:] if section.startswith("## 首错")]
    continuation = [section for section in sections[1:] if section.startswith("## 自动续接状态")]
    keep = [header]
    if result:
        keep.append(result[-1].rstrip())
    if recovery:
        keep.append(recovery[-1].rstrip())
    if continuation:
        keep.append(continuation[-1].rstrip())
    compact = "\n\n".join(keep) + "\n"
    path.write_text(fit(compact, limit), encoding="utf-8")
    return True


def main() -> int:
    limits = json.loads(BUDGET.read_text(encoding="utf-8"))["limits"]
    changed = []
    if compact_handoff(int(limits["handoff_bytes"])):
        changed.append(str(HANDOFF.relative_to(ROOT)))
    for path in sorted(TASKS.glob("FW-*.md")):
        if compact_card(path, int(limits["task_card_bytes"])):
            changed.append(str(path.relative_to(ROOT)))
    if changed:
        print("CONTINUATION_DOCS_COMPACTED: " + ", ".join(changed))
    else:
        print("CONTINUATION_DOCS_WITHIN_BUDGET")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())