"""``hermes debug`` — debug tools for Hermes Agent.

Currently supports:
    hermes debug share    Upload debug report (system info + logs) to a
                          paste service and print a shareable URL.
"""

import io
import json
import os
import sys
import time
import urllib.error
import urllib.parse
import urllib.request
from dataclasses import dataclass
from pathlib import Path
from typing import Optional

from hermes_constants import get_hermes_home


# ---------------------------------------------------------------------------
# Paste services — try paste.rs first, dpaste.com as fallback.
# ---------------------------------------------------------------------------

_PASTE_RS_URL = "https://paste.rs/"
_DPASTE_COM_URL = "https://dpaste.com/api/"

# Maximum bytes to read from a single log file for upload.
# paste.rs caps at ~1 MB; we stay under that with headroom.
_MAX_LOG_BYTES = 512_000

# Auto-delete pastes after this many seconds (6 hours).
_AUTO_DELETE_SECONDS = 21600


# ---------------------------------------------------------------------------
# Pending-deletion tracking (replaces the old fork-and-sleep subprocess).
# ---------------------------------------------------------------------------

def _pending_file() -> Path:
    """Path to ``~/.hermes/pastes/pending.json``.

    Each entry: ``{"url": "...", "expire_at": <unix_ts>}``.  Scheduled
    DELETEs used to be handled by spawning a detached Python process per
    paste that slept for 6 hours; those accumulated forever if the user
    ran ``hermes debug share`` repeatedly.  We now persist the schedule
    to disk and sweep expired entries on the next debug invocation.
    """
    return get_hermes_home() / "pastes" / "pending.json"


def _load_pending() -> list[dict]:
    path = _pending_file()
    if not path.exists():
        return []
    try:
        data = json.loads(path.read_text(encoding="utf-8"))
        if isinstance(data, list):
            # Filter to well-formed entries only
            return [
                e for e in data
                if isinstance(e, dict) and "url" in e and "expire_at" in e
            ]
    except (OSError, ValueError, json.JSONDecodeError):
        pass
    return []


def _save_pending(entries: list[dict]) -> None:
    path = _pending_file()
    try:
        path.parent.mkdir(parents=True, exist_ok=True)
        tmp = path.with_suffix(".json.tmp")
        tmp.write_text(json.dumps(entries, indent=2), encoding="utf-8")
        os.replace(tmp, path)
    except OSError:
        # Non-fatal — worst case the user has to run ``hermes debug delete``
        # manually.
        pass


def _record_pending(urls: list[str], delay_seconds: int = _AUTO_DELETE_SECONDS) -> None:
    """Record *urls* for deletion at ``now + delay_seconds``.

    Only paste.rs URLs are recorded (dpaste.com auto-expires).  Entries
    are merged into any existing pending.json.
    """
    paste_rs_urls = [u for u in urls if _extract_paste_id(u)]
    if not paste_rs_urls:
        return

    entries = _load_pending()
    # Dedupe by URL: keep the later expire_at if same URL appears twice
    by_url: dict[str, float] = {e["url"]: float(e["expire_at"]) for e in entries}
    expire_at = time.time() + delay_seconds
    for u in paste_rs_urls:
        by_url[u] = max(expire_at, by_url.get(u, 0.0))
    merged = [{"url": u, "expire_at": ts} for u, ts in by_url.items()]
    _save_pending(merged)


def _sweep_expired_pastes(now: Optional[float] = None) -> tuple[int, int]:
    """Synchronously DELETE any pending pastes whose ``expire_at`` has passed.

    Returns ``(deleted, remaining)``.  Best-effort: failed deletes stay in
    the pending file and will be retried on the next sweep.  Silent —
    intended to be called from every ``hermes debug`` invocation with
    minimal noise.
    """
    entries = _load_pending()
    if not entries:
        return (0, 0)

    current = time.time() if now is None else now
    deleted = 0
    remaining: list[dict] = []

    for entry in entries:
        try:
            expire_at = float(entry.get("expire_at", 0))
        except (TypeError, ValueError):
            continue  # drop malformed entries
        if expire_at > current:
            remaining.append(entry)
            continue

        url = entry.get("url", "")
        try:
            if delete_paste(url):
                deleted += 1
                continue
        except Exception:
            # Network hiccup, 404 (already gone), etc. — drop the entry
            # after a grace period; don't retry forever.
            pass

        # Retain failed deletes for up to 24h past expiration, then give up.
        if expire_at + 86400 > current:
            remaining.append(entry)
        else:
            deleted += 1  # count as reaped (paste.rs will GC eventually)

    if deleted:
        _save_pending(remaining)

    return (deleted, len(remaining))


def _best_effort_sweep_expired_pastes() -> None:
    """Attempt pending-paste cleanup without letting /debug fail offline."""
    try:
        _sweep_expired_pastes()
    except Exception:
        pass


# ---------------------------------------------------------------------------
# Privacy / delete helpers
# ---------------------------------------------------------------------------

_PRIVACY_NOTICE = """\
⚠️  This will upload the following to a public paste service:
  • System info (OS, Python version, Hermes version, provider, which API keys
    are configured — NOT the actual keys)
  • Recent log lines (agent.log, errors.log, gateway.log — may contain
    conversation fragments and file paths)
  • Full agent.log and gateway.log (up to 512 KB each — likely contains
    conversation content, tool outputs, and file paths)

Pastes auto-delete after 6 hours.
"""

_GATEWAY_PRIVACY_NOTICE = (
    "⚠️ **Privacy notice:** This uploads system info + recent log tails "
    "(may contain conversation fragments) to a public paste service. "
    "Full logs are NOT included from the gateway — use `hermes debug share` "
    "from the CLI for full log uploads.\n"
    "Pastes auto-delete after 6 hours."
)


def _extract_paste_id(url: str) -> Optional[str]:
    """Extract the paste ID from a paste.rs or dpaste.com URL.

    Returns the ID string, or None if the URL doesn't match a known service.
    """
    url = url.strip().rstrip("/")
    for prefix in ("https://paste.rs/", "http://paste.rs/"):
        if url.startswith(prefix):
            return url[len(prefix):]
    return None


def delete_paste(url: str) -> bool:
    """Delete a paste from paste.rs.  Returns True on success.

    Only paste.rs supports unauthenticated DELETE.  dpaste.com pastes
    expire automatically but cannot be deleted via API.
    """
    paste_id = _extract_paste_id(url)
    if not paste_id:
        raise ValueError(
            f"Cannot delete: only paste.rs URLs are supported.  Got: {url}"
        )

    target = f"{_PASTE_RS_URL}{paste_id}"
    req = urllib.request.Request(
        target, method="DELETE",
        headers={"User-Agent": "hermes-agent/debug-share"},
    )
    with urllib.request.urlopen(req, timeout=30) as resp:
        return 200 <= resp.status < 300


def _schedule_auto_delete(urls: list[str], delay_seconds: int = _AUTO_DELETE_SECONDS):
    """Record *urls* for deletion ``delay_seconds`` from now.

    Previously this spawned a detached Python subprocess per call that slept
    for 6 hours and then issued DELETE requests.  Those subprocesses leaked —
    every ``hermes debug share`` invocation added ~20 MB of resident Python
    interpreters that never exited until the sleep completed.

    The replacement is stateless: we append to ``~/.hermes/pastes/pending.json``
    and rely on opportunistic sweeps (``_sweep_expired_pastes``) called from
    every ``hermes debug`` invocation.  If the user never runs ``hermes debug``
    again, paste.rs's own retention policy handles cleanup.
    """
    _record_pending(urls, delay_seconds=delay_seconds)


def _delete_hint(url: str) -> str:
    """Return a one-liner delete command for the given paste URL."""
    paste_id = _extract_paste_id(url)
    if paste_id:
        return f"hermes debug delete {url}"
    # dpaste.com — no API delete, expires on its own.
    return "(auto-expires per dpaste.com policy)"


def _upload_paste_rs(content: str) -> str:
    """Upload to paste.rs.  Returns the paste URL.

    paste.rs accepts a plain POST body and returns the URL directly.
    """
    data = content.encode("utf-8")
    req = urllib.request.Request(
        _PASTE_RS_URL, data=data, method="POST",
        headers={
            "Content-Type": "text/plain; charset=utf-8",
            "User-Agent": "hermes-agent/debug-share",
        },
    )
    with urllib.request.urlopen(req, timeout=30) as resp:
        url = resp.read().decode("utf-8").strip()
    if not url.startswith("http"):
        raise ValueError(f"Unexpected response from paste.rs: {url[:200]}")
    return url


def _upload_dpaste_com(content: str, expiry_days: int = 7) -> str:
    """Upload to dpaste.com.  Returns the paste URL.

    dpaste.com uses multipart form data.
    """
    boundary = "----HermesDebugBoundary9f3c"

    def _field(name: str, value: str) -> str:
        return (
            f"--{boundary}\r\n"
            f'Content-Disposition: form-data; name="{name}"\r\n'
            f"\r\n"
            f"{value}\r\n"
        )

    body = (
        _field("content", content)
        + _field("syntax", "text")
        + _field("expiry_days", str(expiry_days))
        + f"--{boundary}--\r\n"
    ).encode("utf-8")

    req = urllib.request.Request(
        _DPASTE_COM_URL, data=body, method="POST",
        headers={
            "Content-Type": f"multipart/form-data; boundary={boundary}",
            "User-Agent": "hermes-agent/debug-share",
        },
    )
    with urllib.request.urlopen(req, timeout=30) as resp:
        url = resp.read().decode("utf-8").strip()
    if not url.startswith("http"):
        raise ValueError(f"Unexpected response from dpaste.com: {url[:200]}")
    return url


def upload_to_pastebin(content: str, expiry_days: int = 7) -> str:
    """Upload *content* to a paste service, trying paste.rs then dpaste.com.

    Returns the paste URL on success, raises on total failure.
    """
    errors: list[str] = []

    # Try paste.rs first (simple, fast)
    try:
        return _upload_paste_rs(content)
    except Exception as exc:
        errors.append(f"paste.rs: {exc}")

    # Fallback: dpaste.com (supports expiry)
    try:
        return _upload_dpaste_com(content, expiry_days=expiry_days)
    except Exception as exc:
        errors.append(f"dpaste.com: {exc}")

    raise RuntimeError(
        "Failed to upload to any paste service:\n  " + "\n  ".join(errors)
    )


# ---------------------------------------------------------------------------
# Log file reading
# ---------------------------------------------------------------------------


@dataclass
class LogSnapshot:
    """Single-read snapshot of a log file used by debug-share."""

    path: Optional[Path]
    tail_text: str
    full_text: Optional[str]


def _primary_log_path(log_name: str) -> Optional[Path]:
    """Where *log_name* would live if present. Doesn't check existence."""
    from hermes_cli.logs import LOG_FILES

    filename = LOG_FILES.get(log_name)
    return (get_hermes_home() / "logs" / filename) if filename else None


def _resolve_log_path(log_name: str) -> Optional[Path]:
    """Find the log file for *log_name*, falling back to the .1 rotation.

    Returns the first non-empty candidate (primary, then .1), or None.
    Callers distinguish 'empty primary' from 'truly missing' via
    :func:`_primary_log_path`.
    """
    primary = _primary_log_path(log_name)
    if primary is None:
        return None

    if primary.exists() and primary.stat().st_size > 0:
        return primary

    rotated = primary.parent / f"{primary.name}.1"
    if rotated.exists() and rotated.stat().st_size > 0:
        return rotated

    return None


def _capture_log_snapshot(
    log_name: str,
    *,
    tail_lines: int,
    max_bytes: int = _MAX_LOG_BYTES,
) -> LogSnapshot:
    """Capture a log once and derive summary/full-log views from it.

    The report tail and standalone log upload must come from the same file
    snapshot. Otherwise a rotation/truncate between reads can make the report
    look newer than the uploaded ``agent.log`` paste.
    """
    log_path = _resolve_log_path(log_name)
    if log_path is None:
        primary = _primary_log_path(log_name)
        tail = "(file empty)" if primary and primary.exists() else "(file not found)"
        return LogSnapshot(path=None, tail_text=tail, full_text=None)

    try:
        size = log_path.stat().st_size
        if size == 0:
            # race: file was truncated between _resolve_log_path and stat
            return LogSnapshot(path=log_path, tail_text="(file empty)", full_text=None)

        with open(log_path, "rb") as f:
            if size <= max_bytes:
                raw = f.read()
                truncated = False
            else:
                # Read from the end until we have enough bytes for the
                # standalone upload and enough newline context to render the
                # summary tail from the same snapshot.
                chunk_size = 8192
                pos = size
                chunks: list[bytes] = []
                total = 0
                newline_count = 0

                while pos > 0 and (total < max_bytes or newline_count <= tail_lines + 1) and total < max_bytes * 2:
                    read_size = min(chunk_size, pos)
                    pos -= read_size
                    f.seek(pos)
                    chunk = f.read(read_size)
                    chunks.insert(0, chunk)
                    total += len(chunk)
                    newline_count += chunk.count(b"\n")
                    chunk_size = min(chunk_size * 2, 65536)

                raw = b"".join(chunks)
                truncated = pos > 0

        full_raw = raw
        if truncated and len(full_raw) > max_bytes:
            cut = len(full_raw) - max_bytes
            # Check whether the cut lands exactly on a line boundary.  If the
            # byte just before the cut position is a newline the first retained
            # byte starts a complete line and we should keep it.  Only drop a
            # partial first line when we're genuinely mid-line.
            on_boundary = cut > 0 and full_raw[cut - 1 : cut] == b"\n"
            full_raw = full_raw[cut:]
            if not on_boundary and b"\n" in full_raw:
                full_raw = full_raw.split(b"\n", 1)[1]

        all_text = raw.decode("utf-8", errors="replace")
        tail_text = "".join(all_text.splitlines(keepends=True)[-tail_lines:]).rstrip("\n")

        full_text = full_raw.decode("utf-8", errors="replace")
        if truncated:
            full_text = f"[... truncated — showing last ~{max_bytes // 1024}KB ...]\n{full_text}"

        return LogSnapshot(path=log_path, tail_text=tail_text, full_text=full_text)
    except Exception as exc:
        return LogSnapshot(path=log_path, tail_text=f"(error reading: {exc})", full_text=None)


def _capture_default_log_snapshots(log_lines: int) -> dict[str, LogSnapshot]:
    """Capture all logs used by debug-share exactly once."""
    errors_lines = min(log_lines, 100)
    return {
        "agent": _capture_log_snapshot("agent", tail_lines=log_lines),
        "errors": _capture_log_snapshot("errors", tail_lines=errors_lines),
        "gateway": _capture_log_snapshot("gateway", tail_lines=errors_lines),
    }


# ---------------------------------------------------------------------------
# Debug report collection
# ---------------------------------------------------------------------------

def _capture_dump() -> str:
    """Run ``hermes dump`` and return its stdout as a string."""
    from hermes_cli.dump import run_dump

    class _FakeArgs:
        show_keys = False

    old_stdout = sys.stdout
    sys.stdout = capture = io.StringIO()
    try:
        run_dump(_FakeArgs())
    except SystemExit:
        pass
    finally:
        sys.stdout = old_stdout

    return capture.getvalue()


def collect_debug_report(
    *,
    log_lines: int = 200,
    dump_text: str = "",
    log_snapshots: Optional[dict[str, LogSnapshot]] = None,
) -> str:
    """Build the summary debug report: system dump + log tails.

    Parameters
    ----------
    log_lines
        Number of recent lines to include per log file.
    dump_text
        Pre-captured dump output.  If empty, ``hermes dump`` is run
        internally.

    Returns the report as a plain-text string ready for upload.
    """
    buf = io.StringIO()

    if not dump_text:
        dump_text = _capture_dump()
    buf.write(dump_text)

    if log_snapshots is None:
        log_snapshots = _capture_default_log_snapshots(log_lines)

    # ── Recent log tails (summary only) ──────────────────────────────────
    buf.write("\n\n")
    buf.write(f"--- agent.log (last {log_lines} lines) ---\n")
    buf.write(log_snapshots["agent"].tail_text)
    buf.write("\n\n")

    errors_lines = min(log_lines, 100)
    buf.write(f"--- errors.log (last {errors_lines} lines) ---\n")
    buf.write(log_snapshots["errors"].tail_text)
    buf.write("\n\n")

    buf.write(f"--- gateway.log (last {errors_lines} lines) ---\n")
    buf.write(log_snapshots["gateway"].tail_text)
    buf.write("\n")

    return buf.getvalue()


# ---------------------------------------------------------------------------
# CLI entry points
# ---------------------------------------------------------------------------

def run_debug_share(args):
    """Collect debug report + full logs, upload each, print URLs."""
    _best_effort_sweep_expired_pastes()

    log_lines = getattr(args, "lines", 200)
    expiry = getattr(args, "expire", 7)
    local_only = getattr(args, "local", False)

    if not local_only:
        print(_PRIVACY_NOTICE)

    print("Collecting debug report...")

    # Capture dump once — prepended to every paste for context.
    dump_text = _capture_dump()
    log_snapshots = _capture_default_log_snapshots(log_lines)

    report = collect_debug_report(
        log_lines=log_lines,
        dump_text=dump_text,
        log_snapshots=log_snapshots,
    )
    agent_log = log_snapshots["agent"].full_text
    gateway_log = log_snapshots["gateway"].full_text

    # Prepend dump header to each full log so every paste is self-contained.
    if agent_log:
        agent_log = dump_text + "\n\n--- full agent.log ---\n" + agent_log
    if gateway_log:
        gateway_log = dump_text + "\n\n--- full gateway.log ---\n" + gateway_log

    if local_only:
        print(report)
        if agent_log:
            print(f"\n\n{'=' * 60}")
            print("FULL agent.log")
            print(f"{'=' * 60}\n")
            print(agent_log)
        if gateway_log:
            print(f"\n\n{'=' * 60}")
            print("FULL gateway.log")
            print(f"{'=' * 60}\n")
            print(gateway_log)
        return

    print("Uploading...")
    urls: dict[str, str] = {}
    failures: list[str] = []

    # 1. Summary report (required)
    try:
        urls["Report"] = upload_to_pastebin(report, expiry_days=expiry)
    except RuntimeError as exc:
        print(f"\nUpload failed: {exc}", file=sys.stderr)
        print("\nFull report printed below — copy-paste it manually:\n")
        print(report)
        sys.exit(1)

    # 2. Full agent.log (optional)
    if agent_log:
        try:
            urls["agent.log"] = upload_to_pastebin(agent_log, expiry_days=expiry)
        except Exception as exc:
            failures.append(f"agent.log: {exc}")

    # 3. Full gateway.log (optional)
    if gateway_log:
        try:
            urls["gateway.log"] = upload_to_pastebin(gateway_log, expiry_days=expiry)
        except Exception as exc:
            failures.append(f"gateway.log: {exc}")

    # Print results
    label_width = max(len(k) for k in urls)
    print(f"\nDebug report uploaded:")
    for label, url in urls.items():
        print(f"  {label:<{label_width}}  {url}")

    if failures:
        print(f"\n  (failed to upload: {', '.join(failures)})")

    # Schedule auto-deletion after 6 hours
    _schedule_auto_delete(list(urls.values()))
    print(f"\n⏱  Pastes will auto-delete in 6 hours.")

    # Manual delete fallback
    print(f"To delete now:  hermes debug delete <url>")

    print(f"\nShare these links with the Hermes team for support.")


def run_debug_delete(args):
    """Delete one or more paste URLs uploaded by /debug."""
    urls = getattr(args, "urls", [])
    if not urls:
        print("Usage: hermes debug delete <url> [<url> ...]")
        print("  Deletes paste.rs pastes uploaded by 'hermes debug share'.")
        return

    for url in urls:
        try:
            ok = delete_paste(url)
            if ok:
                print(f"  ✓ Deleted: {url}")
            else:
                print(f"  ✗ Failed to delete: {url} (unexpected response)")
        except ValueError as exc:
            print(f"  ✗ {exc}")
        except Exception as exc:
            print(f"  ✗ Could not delete {url}: {exc}")


def run_debug(args):
    """Route debug subcommands."""
    # Opportunistic sweep of expired pastes on every ``hermes debug`` call.
    # Replaces the old per-paste sleeping subprocess that used to leak as
    # one orphaned Python interpreter per scheduled deletion.  Silent and
    # best-effort — any failure is swallowed so ``hermes debug`` stays
    # reliable even when offline.
    try:
        _sweep_expired_pastes()
    except Exception:
        pass

    subcmd = getattr(args, "debug_command", None)
    if subcmd == "share":
        run_debug_share(args)
    elif subcmd == "delete":
        run_debug_delete(args)
    else:
        # Default: show help
        print("Usage: hermes debug <command>")
        print()
        print("Commands:")
        print("  share    Upload debug report to a paste service and print URL")
        print("  delete   Delete a previously uploaded paste")
        print()
        print("Options (share):")
        print("  --lines N    Number of log lines to include (default: 200)")
        print("  --expire N   Paste expiry in days (default: 7)")
        print("  --local      Print report locally instead of uploading")
        print()
        print("Options (delete):")
        print("  <url> ...    One or more paste URLs to delete")