#!/usr/bin/env python3
"""
Webhook health dashboard for fleet agent endpoints.

Issue: #855 in Timmy_Foundation/the-nexus

Probes each configured /health endpoint, persists the last-known-good state to a
JSON log, and generates a markdown dashboard in ~/.hermes/burn-logs/.

Default targets:
- bezalel: http://127.0.0.1:8650/health
- allegro: http://127.0.0.1:8651/health
- ezra:     http://127.0.0.1:8652/health
- adagio:   http://127.0.0.1:8653/health

Environment overrides:
- WEBHOOK_HEALTH_TARGETS="allegro=http://127.0.0.1:8651/health,ezra=http://127.0.0.1:8652/health"
- WEBHOOK_HEALTH_TIMEOUT=3
- WEBHOOK_STALE_AFTER=300
- WEBHOOK_HEALTH_OUTPUT=/custom/webhook-health-latest.md
- WEBHOOK_HEALTH_HISTORY=/custom/webhook-health-history.json
"""

from __future__ import annotations

import argparse
import json
import os
import time
import urllib.error
import urllib.request
from dataclasses import asdict, dataclass
from pathlib import Path
from typing import Any

DEFAULT_TARGETS = {
    "bezalel": "http://127.0.0.1:8650/health",
    "allegro": "http://127.0.0.1:8651/health",
    "ezra": "http://127.0.0.1:8652/health",
    "adagio": "http://127.0.0.1:8653/health",
}

DEFAULT_TIMEOUT = float(os.environ.get("WEBHOOK_HEALTH_TIMEOUT", "3"))
DEFAULT_STALE_AFTER = int(os.environ.get("WEBHOOK_STALE_AFTER", "300"))
DEFAULT_OUTPUT = Path(
    os.environ.get(
        "WEBHOOK_HEALTH_OUTPUT",
        str(Path.home() / ".hermes" / "burn-logs" / "webhook-health-latest.md"),
    )
).expanduser()
DEFAULT_HISTORY = Path(
    os.environ.get(
        "WEBHOOK_HEALTH_HISTORY",
        str(Path.home() / ".hermes" / "burn-logs" / "webhook-health-history.json"),
    )
).expanduser()


@dataclass
class AgentHealth:
    name: str
    url: str
    http_status: int | None
    healthy: bool
    latency_ms: int | None
    stale: bool
    last_success_ts: float | None
    checked_at: float
    message: str

    def status_icon(self) -> str:
        if self.healthy:
            return "🟢"
        if self.stale:
            return "🔴"
        return "🟠"

    def last_success_age_seconds(self) -> int | None:
        if self.last_success_ts is None:
            return None
        return max(0, int(self.checked_at - self.last_success_ts))


def parse_targets(raw: str | None) -> dict[str, str]:
    if not raw:
        return dict(DEFAULT_TARGETS)
    targets: dict[str, str] = {}
    for chunk in raw.split(","):
        chunk = chunk.strip()
        if not chunk:
            continue
        if "=" not in chunk:
            raise ValueError(f"Invalid target spec: {chunk!r}")
        name, url = chunk.split("=", 1)
        targets[name.strip()] = url.strip()
    if not targets:
        raise ValueError("No valid targets parsed")
    return targets


def load_history(path: Path) -> dict[str, Any]:
    if not path.exists():
        return {"agents": {}, "runs": []}
    return json.loads(path.read_text(encoding="utf-8"))


def save_history(path: Path, history: dict[str, Any]) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_text(json.dumps(history, indent=2, sort_keys=True), encoding="utf-8")


def probe_health(url: str, timeout: float) -> tuple[bool, int | None, int | None, str]:
    started = time.perf_counter()
    req = urllib.request.Request(url, headers={"User-Agent": "the-nexus/webhook-health-dashboard"})
    try:
        with urllib.request.urlopen(req, timeout=timeout) as resp:
            body = resp.read(512)
            latency_ms = int((time.perf_counter() - started) * 1000)
            status = getattr(resp, "status", None) or 200
            message = f"HTTP {status}"
            if body:
                try:
                    payload = json.loads(body.decode("utf-8", errors="replace"))
                    if isinstance(payload, dict) and payload.get("status"):
                        message = f"HTTP {status} — {payload['status']}"
                except Exception:
                    pass
            return 200 <= status < 300, status, latency_ms, message
    except urllib.error.HTTPError as e:
        latency_ms = int((time.perf_counter() - started) * 1000)
        return False, e.code, latency_ms, f"HTTP {e.code}"
    except urllib.error.URLError as e:
        latency_ms = int((time.perf_counter() - started) * 1000)
        return False, None, latency_ms, f"URL error: {e.reason}"
    except Exception as e:
        latency_ms = int((time.perf_counter() - started) * 1000)
        return False, None, latency_ms, f"Probe failed: {e}"


def check_agents(
    targets: dict[str, str],
    history: dict[str, Any],
    timeout: float = DEFAULT_TIMEOUT,
    stale_after: int = DEFAULT_STALE_AFTER,
) -> list[AgentHealth]:
    checked_at = time.time()
    results: list[AgentHealth] = []
    agent_state = history.setdefault("agents", {})

    for name, url in targets.items():
        state = agent_state.get(name, {})
        last_success_ts = state.get("last_success_ts")
        ok, http_status, latency_ms, message = probe_health(url, timeout)
        if ok:
            last_success_ts = checked_at
        stale = False
        if not ok and last_success_ts is not None:
            stale = (checked_at - float(last_success_ts)) > stale_after
        result = AgentHealth(
            name=name,
            url=url,
            http_status=http_status,
            healthy=ok,
            latency_ms=latency_ms,
            stale=stale,
            last_success_ts=last_success_ts,
            checked_at=checked_at,
            message=message,
        )
        agent_state[name] = {
            "url": url,
            "last_success_ts": last_success_ts,
            "last_http_status": http_status,
            "last_message": message,
            "last_checked_at": checked_at,
        }
        results.append(result)

    history.setdefault("runs", []).append(
        {
            "checked_at": checked_at,
            "healthy_count": sum(1 for r in results if r.healthy),
            "unhealthy_count": sum(1 for r in results if not r.healthy),
            "agents": [asdict(r) for r in results],
        }
    )
    history["runs"] = history["runs"][-100:]
    return results


def _format_age(seconds: int | None) -> str:
    if seconds is None:
        return "never"
    if seconds < 60:
        return f"{seconds}s ago"
    if seconds < 3600:
        return f"{seconds // 60}m ago"
    return f"{seconds // 3600}h ago"


def to_markdown(results: list[AgentHealth], generated_at: float | None = None) -> str:
    generated_at = generated_at or time.time()
    ts = time.strftime("%Y-%m-%d %H:%M:%S UTC", time.gmtime(generated_at))
    healthy = sum(1 for r in results if r.healthy)
    total = len(results)

    lines = [
        f"# Agent Webhook Health Dashboard — {ts}",
        "",
        f"Healthy: {healthy}/{total}",
        "",
        "| Agent | Status | HTTP | Latency | Last success | Endpoint | Notes |",
        "|:------|:------:|:----:|--------:|:------------|:---------|:------|",
    ]
    for result in results:
        http = str(result.http_status) if result.http_status is not None else "—"
        latency = f"{result.latency_ms}ms" if result.latency_ms is not None else "—"
        lines.append(
            "| {name} | {icon} | {http} | {latency} | {last_success} | `{url}` | {message} |".format(
                name=result.name,
                icon=result.status_icon(),
                http=http,
                latency=latency,
                last_success=_format_age(result.last_success_age_seconds()),
                url=result.url,
                message=result.message,
            )
        )

    stale_agents = [r.name for r in results if r.stale]
    if stale_agents:
        lines.extend([
            "",
            "## Stale agents",
            ", ".join(stale_agents),
        ])

    lines.extend([
        "",
        "Generated by `bin/webhook_health_dashboard.py`.",
    ])
    return "\n".join(lines)


def write_dashboard(path: Path, markdown: str) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_text(markdown + "\n", encoding="utf-8")


def parse_args(argv: list[str]) -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Generate webhook health dashboard")
    parser.add_argument("--targets", default=os.environ.get("WEBHOOK_HEALTH_TARGETS"))
    parser.add_argument("--timeout", type=float, default=DEFAULT_TIMEOUT)
    parser.add_argument("--stale-after", type=int, default=DEFAULT_STALE_AFTER)
    parser.add_argument("--output", type=Path, default=DEFAULT_OUTPUT)
    parser.add_argument("--history", type=Path, default=DEFAULT_HISTORY)
    return parser.parse_args(argv)


def main(argv: list[str] | None = None) -> int:
    args = parse_args(argv or sys.argv[1:])
    targets = parse_targets(args.targets)
    history = load_history(args.history)
    results = check_agents(targets, history, timeout=args.timeout, stale_after=args.stale_after)
    save_history(args.history, history)
    dashboard = to_markdown(results)
    write_dashboard(args.output, dashboard)
    print(args.output)
    print(f"healthy={sum(1 for r in results if r.healthy)} total={len(results)}")
    return 0


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