"""
modules/context_carry.py - Phase 7 context carry across restarts

Stores:
  - last mode
  - last few user/assistant interactions (compact)
  - last active tasks snapshot

Used to:
  - rebuild a small "resume" hint for the brain
  - show continuity after a crash/reboot
"""

from __future__ import annotations

import json
import os
import time
from datetime import datetime

from config import DATA_DIR

CTX_FILE = os.path.join(DATA_DIR, "session_context.json")


def _load() -> dict:
    if not os.path.exists(CTX_FILE):
        return {}
    try:
        with open(CTX_FILE, "r") as f:
            data = json.load(f)
        if isinstance(data, dict):
            return data
    except Exception:
        pass
    return {}


def _save(data: dict) -> None:
    os.makedirs(os.path.dirname(CTX_FILE), exist_ok=True)
    try:
        with open(CTX_FILE, "w") as f:
            json.dump(data, f, indent=2)
    except Exception:
        pass


def snapshot(mode: str | None = None) -> None:
    """
    Save a compact snapshot for resuming context.
    """
    data = _load()
    data["time"] = time.time()
    data["iso"] = datetime.now().isoformat()
    if mode:
        data["mode"] = mode

    # last interactions (small)
    try:
        from modules.memory import INTERACTION_FILE
        with open(INTERACTION_FILE, "r") as f:
            interactions = json.load(f)
        if not isinstance(interactions, list):
            interactions = []
        compact = interactions[-12:]
        data["recent"] = [
            {"role": it.get("role", ""), "text": (it.get("text", "")[:180]), "time": it.get("time", 0)}
            for it in compact
        ]
    except Exception:
        pass

    # tasks snapshot
    try:
        from modules.memory import get_unfinished_tasks
        tasks = get_unfinished_tasks()
        data["tasks"] = tasks[:10]
    except Exception:
        pass

    _save(data)


def resume_block(max_lines: int = 12) -> str:
    """
    Return a short block injected into prompts for continuity.
    """
    data = _load()
    if not data:
        return ""

    lines: list[str] = []
    ts = data.get("iso") or ""
    if ts:
        lines.append(f"[SESSION CONTEXT] Last snapshot: {ts}")
    mode = data.get("mode")
    if mode:
        lines.append(f"[LAST MODE] {mode}")
    tasks = data.get("tasks") or []
    if tasks:
        lines.append("[PENDING] " + "; ".join(tasks[:3]))

    recent = data.get("recent") or []
    if recent:
        lines.append("[RECENT]")
        for it in recent[-8:]:
            r = (it.get("role") or "").upper()
            t = it.get("text") or ""
            if r and t:
                lines.append(f"{r}: {t}")

    return "\n".join(lines[:max_lines])