"""In-process driver for the fpga-imx6-flow LangGraph workflow.

Builds the compiled graph from the project's app package and drives it with a
persistent SqliteSaver — no `langgraph dev` server. Mirrors the fpga-flow helper
convention: exit code 0 = done, 1 = error, 2 = interrupt fired.

Commands:
    start   --project-dir <dir> [--program-mode bitstream|flash] [--bit-path ..]
            [--flash-path ..] [--thread-id ..] [--real] [--max-iterations N]
    resume  --project-dir <dir> --resume-json '<json>' [--thread-id ..] [--real]
    status  --project-dir <dir> [--thread-id ..]

Output: one JSON line on stdout describing status + the pending interrupt (if any).
Run via the env python directly or `conda run --no-capture-output` to avoid the
Windows GBK console re-encode crash on Chinese interrupt payloads.
"""
from __future__ import annotations

import argparse
import json
import os
import sys
from pathlib import Path

try:
    sys.stdout.reconfigure(encoding="utf-8")  # emit UTF-8 even on a GBK console
except Exception:
    pass

DEFAULT_PROJECT = r"E:\LangGraph_Design\FPGA-imx6-flow"


def _emit(obj: dict, code: int) -> None:
    print(json.dumps(obj, ensure_ascii=False))
    sys.exit(code)


def _pending_interrupt(snap):
    for task in snap.tasks:
        if task.interrupts:
            return task.interrupts[0].value
    return None


def main() -> None:
    ap = argparse.ArgumentParser(description="Drive the fpga-imx6-flow graph in-process.")
    ap.add_argument("command", choices=["start", "resume", "status"])
    ap.add_argument("--project-dir", default=DEFAULT_PROJECT)
    ap.add_argument("--thread-id", default="imx6-skill-1")
    ap.add_argument("--resume-json", default="")
    ap.add_argument("--program-mode", default="bitstream", choices=["bitstream", "flash"])
    ap.add_argument("--bit-path", default="")
    ap.add_argument("--flash-path", default="")
    ap.add_argument("--real", action="store_true",
                    help="drive real hardware (workflow tools_* must be wired; default is MOCK dry-run)")
    ap.add_argument("--max-iterations", type=int, default=8)
    ap.add_argument("--max-hw-retry", type=int, default=3)
    args = ap.parse_args()

    project = Path(args.project_dir)
    if not (project / "app" / "main_graph.py").exists():
        _emit({"status": "error",
               "error": f"app/main_graph.py not found under {project}; check --project-dir"}, 1)

    # MOCK by default so the design loop can be dry-run with no hardware attached.
    os.environ["FPGA_IMX6_MOCK"] = "0" if args.real else "1"
    sys.path.insert(0, str(project))

    try:
        from langgraph.checkpoint.sqlite import SqliteSaver
        from langgraph.types import Command
        from app.main_graph import build_graph
    except Exception as exc:  # noqa: BLE001
        _emit({"status": "error",
               "error": f"import failed: {exc}. Run /langgraph-vivado-install to set up the env."}, 1)

    runs = project / "runs"
    runs.mkdir(exist_ok=True)
    db = str(runs / "skill_checkpoint.sqlite")
    cfg = {"configurable": {"thread_id": args.thread_id}}

    with SqliteSaver.from_conn_string(db) as cp:
        graph = build_graph(checkpointer=cp)
        try:
            if args.command == "start":
                init = {
                    "iteration": 0,
                    "program_mode": args.program_mode,
                    "bit_path": args.bit_path,
                    "flash_path": args.flash_path,
                    "max_hw_retry": args.max_hw_retry,
                    "max_iterations": args.max_iterations,
                    "history": [],
                }
                graph.invoke(init, cfg)
            elif args.command == "resume":
                payload = json.loads(args.resume_json) if args.resume_json else {}
                graph.invoke(Command(resume=payload), cfg)
            # status: no invoke, just snapshot
            snap = graph.get_state(cfg)
        except Exception as exc:  # noqa: BLE001
            _emit({"status": "error", "error": str(exc)}, 1)

        if snap.next:
            _emit({
                "status": "interrupt",
                "thread_id": args.thread_id,
                "mock": not args.real,
                "next": list(snap.next),
                "iteration": snap.values.get("iteration"),
                "interrupt": _pending_interrupt(snap),
            }, 2)
        else:
            _emit({
                "status": "done",
                "thread_id": args.thread_id,
                "iteration": snap.values.get("iteration"),
                "steps": len(snap.values.get("history", [])),
            }, 0)


if __name__ == "__main__":
    main()