"""Spawn/stop/list idatui TUI panes in tmux, for an agent to drive over RPC.

The agent (running inside a tmux pane) can open a fresh pane with the TUI
running against a binary, wait until it's ready, drive it over the RPC socket,
then close it — all without a human touching the keyboard.

    # open a binary in a new pane, block until analysed + drivable, print JSON
    python -m idatui.pane spawn --open /abs/path/to/bin
    # -> {"sock": "/run/user/1000/idatui-3f2a.sock", "pane": "%7", "ready": true, ...}

    # drive it (see docs/RPC.md / the idatui-rpc skill)
    python -m idatui.rpcclient --sock <sock> pseudocode target=main

    # inventory + teardown
    python -m idatui.pane list
    python -m idatui.pane stop --sock <sock>        # graceful quit + kill pane

Requires: running inside tmux. Each pane spawns its own private idalib worker
(no shared supervisor). Uses ~/ida-venv/bin/python for the TUI (needs textual)
unless --python / IDATUI_PYTHON says otherwise.
"""
from __future__ import annotations

import argparse
import json
import os
import secrets
import signal
import subprocess
import sys
import time
from typing import Any

from .rpcclient import RpcClient, RpcError

REPO = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
DEFAULT_PY = os.environ.get(
    "IDATUI_PYTHON", os.path.expanduser("~/ida-venv/bin/python"))


def _sockdir() -> str:
    return os.environ.get("XDG_RUNTIME_DIR") or "/tmp"


def _registry_path() -> str:
    return os.path.join(_sockdir(), "idatui-panes.json")


def _load_registry() -> list[dict[str, Any]]:
    try:
        with open(_registry_path()) as f:
            return json.load(f)
    except (OSError, ValueError):
        return []


def _save_registry(rows: list[dict[str, Any]]) -> None:
    tmp = _registry_path() + ".tmp"
    with open(tmp, "w") as f:
        json.dump(rows, f)
    os.replace(tmp, _registry_path())


def _pane_alive(pane: str) -> bool:
    out = subprocess.run(["tmux", "list-panes", "-a", "-F", "#{pane_id}"],
                         capture_output=True, text=True)
    return pane in out.stdout.split()


def _tmux(*args: str) -> str:
    return subprocess.run(["tmux", *args], capture_output=True, text=True,
                          check=True).stdout.strip()


# --------------------------------------------------------------------------- #
# idalib worker reaping
#
# ``pane stop`` kills the TUI pane, but a hard-killed pane can leave its private
# idalib worker (idatui/worker.py) running. A worker is only *safe* to reap when
# no idatui pane is live (then every worker is orphaned), which avoids killing an
# in-use analyser.
# --------------------------------------------------------------------------- #
_WORKER_PATTERN = r"idatui/worker\.py"


def _worker_pids() -> list[int]:
    """PIDs of our private per-pane idalib worker processes (idatui/worker.py),
    never our own PID."""
    try:
        out = subprocess.run(["pgrep", "-f", _WORKER_PATTERN],
                             capture_output=True, text=True)
    except OSError:
        return []
    me = os.getpid()
    pids: list[int] = []
    for tok in out.stdout.split():
        try:
            pid = int(tok)
        except ValueError:
            continue
        if pid != me:
            pids.append(pid)
    return pids


def _count_live_panes() -> int:
    return sum(1 for r in _load_registry() if _pane_alive(r.get("pane", "")))


def _reap_orphan_workers(force: bool = False) -> int:
    """Kill leaked idalib workers when it is safe (no live pane) or ``force``.

    Returns the number of workers signalled. Best-effort; never raises.
    """
    if not force and _count_live_panes() > 0:
        return 0
    reaped = 0
    for pid in _worker_pids():
        try:
            os.kill(pid, signal.SIGKILL)
            reaped += 1
        except OSError:
            pass
    return reaped


# --------------------------------------------------------------------------- #
# spawn
# --------------------------------------------------------------------------- #
def spawn(args) -> int:
    if not os.environ.get("TMUX"):
        print("error: not inside tmux (spawn creates a tmux pane)", file=sys.stderr)
        return 2
    if not args.open and not getattr(args, "project", None):
        print("error: pass --open <binary> or --project <file>", file=sys.stderr)
        return 2

    sock = args.sock or os.path.join(_sockdir(), f"idatui-{secrets.token_hex(3)}.sock")
    project = (os.path.abspath(os.path.expanduser(args.project))
               if getattr(args, "project", None) else None)
    target = os.path.abspath(os.path.expanduser(args.open)) if args.open else None
    if target is not None and not os.path.exists(target):
        print(f"error: no such binary: {target}", file=sys.stderr)
        return 2
    if project is not None and target is None and not os.path.exists(project):
        print(f"error: no such project: {project}", file=sys.stderr)
        return 2

    # Reap workers leaked by previously-stopped/crashed panes so we don't spawn
    # into a full IDA_MCP_MAX_WORKERS (which makes the new TUI hang forever,
    # never reaching ready). No-op while any pane is live.
    reaped = _reap_orphan_workers()
    if reaped:
        print(f"reaped {reaped} orphaned idalib worker(s) before spawn",
              file=sys.stderr)

    # the command the pane runs: the launcher spawns a private idalib worker for
    # this binary and becomes the TUI, so kill-pane tears the whole thing down.
    if project is not None:
        # launch takes: --project FILE [binaries...]; extra binaries are added to
        # the project (and a missing project file is created from them).
        inner = [args.python, "-m", "idatui.launch", "--project", project]
        if target is not None:
            inner.append(target)
        inner += ["--rpc", sock]
    else:
        inner = [args.python, "-m", "idatui.launch", target, "--rpc", sock]
    cmd = f"cd {REPO!r} && exec " + " ".join(_q(a) for a in inner)

    split = ["split-window", "-v" if args.vertical else "-h",
             "-P", "-F", "#{pane_id}"]
    if args.size:
        split += ["-l", str(args.size)]
    if args.detached:
        split += ["-d"]
    anchor = os.environ.get("TMUX_PANE")
    if anchor:
        split += ["-t", anchor]
    split.append(cmd)
    pane = _tmux(*split)

    row = {"sock": sock, "pane": pane, "target": project or target,
           "kind": "project" if project else "open", "started": time.time()}
    reg = [r for r in _load_registry() if r.get("sock") != sock]
    reg.append(row)
    _save_registry(reg)

    ready = _wait_ready(sock, args.timeout, pane)
    row.update(ready)
    print(json.dumps(row))
    return 0 if ready.get("ready") else 1


def _q(s: str) -> str:
    import shlex
    return shlex.quote(s)


def _wait_ready(sock: str, timeout: float, pane: str,
                stuck_after: float = 45.0) -> dict[str, Any]:
    """Poll the socket + ping until the TUI reports ready (or timeout).

    Emits a one-time hint to stderr if it's still not ready after ``stuck_after``
    seconds, so a wedged idalib worker / full worker pool surfaces a diagnostic
    instead of an unexplained silent hang.
    """
    start = time.time()
    deadline = start + timeout
    warned = False
    last: dict[str, Any] = {"ready": False}
    while time.time() < deadline:
        if not _pane_alive(pane):
            return {"ready": False, "error": "pane exited during startup"}
        if os.path.exists(sock):
            try:
                with RpcClient(sock) as c:
                    last = c.call("ping")
                if last.get("ready"):
                    return last
            except (OSError, RpcError, ConnectionError):
                pass
        if not warned and (time.time() - start) > stuck_after:
            warned = True
            why = ("RPC socket not created yet" if not os.path.exists(sock)
                   else "TUI up but analysis not ready")
            print(f"still waiting ({int(time.time() - start)}s): {why}. If this "
                  f"hangs, the idalib worker may be stuck — try "
                  f"`python -m idatui.pane reap`.", file=sys.stderr)
        time.sleep(0.4)
    last = dict(last)
    last["ready"] = False
    last.setdefault("error", "timed out waiting for the TUI to become ready")
    return last


# --------------------------------------------------------------------------- #
# stop / list
# --------------------------------------------------------------------------- #
def stop(args) -> int:
    reg = _load_registry()
    rows = [r for r in reg
            if (args.sock and r.get("sock") == args.sock)
            or (args.pane and r.get("pane") == args.pane)]
    if not rows and args.sock:  # allow stopping an untracked socket
        rows = [{"sock": args.sock, "pane": args.pane}]
    if not rows:
        print("error: no matching pane (need --sock or --pane)", file=sys.stderr)
        return 2
    for r in rows:
        sock, pane = r.get("sock"), r.get("pane")
        if sock and os.path.exists(sock):
            try:  # ask it to quit gracefully first
                with RpcClient(sock) as c:
                    c.call("quit")
                time.sleep(0.4)
            except (OSError, RpcError, ConnectionError):
                pass
        if pane and _pane_alive(pane):
            subprocess.run(["tmux", "kill-pane", "-t", pane],
                           capture_output=True)
        if sock:
            try:
                os.unlink(sock)
            except OSError:
                pass
    _save_registry([r for r in reg if r not in rows])
    # Reap the workers those panes leaked (safe: only fires once no pane is live).
    reaped = _reap_orphan_workers()
    out = {"stopped": [r.get("sock") or r.get("pane") for r in rows]}
    if reaped:
        out["reaped_workers"] = reaped
    print(json.dumps(out))
    return 0


def list_panes(args) -> int:
    reg = _load_registry()
    alive = []
    for r in reg:
        r = dict(r)
        r["pane_alive"] = _pane_alive(r.get("pane", ""))
        r["sock_up"] = bool(r.get("sock") and os.path.exists(r["sock"]))
        if args.prune and not r["pane_alive"]:
            if r.get("sock") and os.path.exists(r["sock"]):
                try:
                    os.unlink(r["sock"])
                except OSError:
                    pass
            continue
        alive.append(r)
    if args.prune:
        _save_registry(alive)
        reaped = _reap_orphan_workers()
        if reaped:
            print(f"reaped {reaped} orphaned idalib worker(s)", file=sys.stderr)
    print(json.dumps(alive, indent=2))
    return 0


def reap(args) -> int:
    """Kill leaked idalib workers (safe when no pane is live; --force overrides)."""
    live = _count_live_panes()
    n = _reap_orphan_workers(force=args.force)
    print(json.dumps({"reaped_workers": n, "live_panes": live, "forced": args.force}))
    if n == 0 and not args.force and live > 0:
        print(f"note: {live} live pane(s) — not reaping in-use workers; pass "
              f"--force to reap anyway", file=sys.stderr)
    return 0


def main(argv: list[str]) -> int:
    p = argparse.ArgumentParser(prog="idatui.pane",
                                description="spawn/manage idatui TUI panes in tmux")
    sub = p.add_subparsers(dest="cmd", required=True)

    sp = sub.add_parser("spawn", help="open a TUI pane and wait until ready")
    sp.add_argument("--open", metavar="PATH",
                    help="binary to open (its dir must be writable)")
    sp.add_argument("--project", metavar="FILE",
                    help="project file to open instead of a single binary; "
                         "any --open paths are added to it (created if absent)")
    sp.add_argument("--sock", help="RPC socket path (default: auto in $XDG_RUNTIME_DIR)")
    sp.add_argument("--python", default=DEFAULT_PY, help=f"python for the TUI ({DEFAULT_PY})")
    sp.add_argument("--vertical", action="store_true", help="split vertically (stacked)")
    sp.add_argument("--size", help="new pane size (tmux -l value, e.g. 60%% or 120)")
    sp.add_argument("--detached", action="store_true", help="don't focus the new pane")
    sp.add_argument("--timeout", type=float, default=300.0,
                    help="seconds to wait for readiness (fresh --open analysis is slow)")
    sp.set_defaults(fn=spawn)

    st = sub.add_parser("stop", help="graceful quit + kill the pane")
    st.add_argument("--sock")
    st.add_argument("--pane")
    st.set_defaults(fn=stop)

    ls = sub.add_parser("list", help="list tracked panes")
    ls.add_argument("--prune", action="store_true", help="drop dead panes (and their sockets)")
    ls.set_defaults(fn=list_panes)

    rp = sub.add_parser("reap", help="kill leaked idalib workers (frees worker slots)")
    rp.add_argument("--force", action="store_true",
                    help="reap even while panes are live (may kill an in-use analyser)")
    rp.set_defaults(fn=reap)

    args = p.parse_args(argv)
    return args.fn(args)


if __name__ == "__main__":
    raise SystemExit(main(sys.argv[1:]))