"""``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 sys
import urllib.error
import urllib.parse
import urllib.request
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


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
# ---------------------------------------------------------------------------

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

    Returns the path if found, or None.
    """
    from hermes_cli.logs import LOG_FILES

    filename = LOG_FILES.get(log_name)
    if not filename:
        return None

    log_dir = get_hermes_home() / "logs"
    primary = log_dir / filename
    if primary.exists() and primary.stat().st_size > 0:
        return primary

    # Fall back to the most recent rotated file (.1).
    rotated = log_dir / f"{filename}.1"
    if rotated.exists() and rotated.stat().st_size > 0:
        return rotated

    return None


def _read_log_tail(log_name: str, num_lines: int) -> str:
    """Read the last *num_lines* from a log file, or return a placeholder."""
    from hermes_cli.logs import _read_last_n_lines

    log_path = _resolve_log_path(log_name)
    if log_path is None:
        return "(file not found)"

    try:
        lines = _read_last_n_lines(log_path, num_lines)
        return "".join(lines).rstrip("\n")
    except Exception as exc:
        return f"(error reading: {exc})"


def _read_full_log(log_name: str, max_bytes: int = _MAX_LOG_BYTES) -> Optional[str]:
    """Read a log file for standalone upload.

    Returns the file content (last *max_bytes* if truncated), or None if the
    file doesn't exist or is empty.
    """
    log_path = _resolve_log_path(log_name)
    if log_path is None:
        return None

    try:
        size = log_path.stat().st_size
        if size == 0:
            return None

        if size <= max_bytes:
            return log_path.read_text(encoding="utf-8", errors="replace")

        # File is larger than max_bytes — read the tail.
        with open(log_path, "rb") as f:
            f.seek(size - max_bytes)
            # Skip partial line at the seek point.
            f.readline()
            content = f.read().decode("utf-8", errors="replace")
        return f"[... truncated — showing last ~{max_bytes // 1024}KB ...]\n{content}"
    except Exception:
        return None


# ---------------------------------------------------------------------------
# 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 = "") -> 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)

    # ── Recent log tails (summary only) ──────────────────────────────────
    buf.write("\n\n")
    buf.write(f"--- agent.log (last {log_lines} lines) ---\n")
    buf.write(_read_log_tail("agent", log_lines))
    buf.write("\n\n")

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

    buf.write(f"--- gateway.log (last {errors_lines} lines) ---\n")
    buf.write(_read_log_tail("gateway", errors_lines))
    buf.write("\n")

    return buf.getvalue()


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

def run_debug_share(args):
    """Collect debug report + full logs, upload each, print URLs."""
    log_lines = getattr(args, "lines", 200)
    expiry = getattr(args, "expire", 7)
    local_only = getattr(args, "local", False)

    print("Collecting debug report...")

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

    report = collect_debug_report(log_lines=log_lines, dump_text=dump_text)
    agent_log = _read_full_log("agent")
    gateway_log = _read_full_log("gateway")

    # 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)})")

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


def run_debug(args):
    """Route debug subcommands."""
    subcmd = getattr(args, "debug_command", None)
    if subcmd == "share":
        run_debug_share(args)
    else:
        # Default: show help
        print("Usage: hermes debug share [--lines N] [--expire N] [--local]")
        print()
        print("Commands:")
        print("  share    Upload debug report to a paste service and print URL")
        print()
        print("Options:")
        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")