"""Read ``WATCHDOG_*`` env into a frozen config (thresholds / intervals / tokens /
URLs / kill-switch), with safe defaults (D1/D8, FR-10).

Every parser is never-raise: a missing / malformed value degrades to its
documented default, the process never crashes on a bad env (the same spirit as
``disk_watchdog.parse_paths``). ``.env.example`` is the canon of the keys.
"""
from __future__ import annotations

import os
from dataclasses import dataclass, field


def _str(env: dict, key: str, default: str) -> str:
    try:
        v = env.get(key)
        if v is None or not str(v).strip():
            return default
        return str(v).strip()
    except Exception:  # noqa: BLE001 - never break config on a bad env
        return default


def _int(env: dict, key: str, default: int) -> int:
    try:
        v = env.get(key)
        if v is None or not str(v).strip():
            return default
        return int(str(v).strip())
    except Exception:  # noqa: BLE001
        return default


def _float(env: dict, key: str, default: float) -> float:
    try:
        v = env.get(key)
        if v is None or not str(v).strip():
            return default
        return float(str(v).strip())
    except Exception:  # noqa: BLE001
        return default


def _bool(env: dict, key: str, default: bool) -> bool:
    try:
        v = env.get(key)
        if v is None or not str(v).strip():
            return default
        return str(v).strip().lower() in ("1", "true", "yes", "on")
    except Exception:  # noqa: BLE001
        return default


def _csv(env: dict, key: str, default: list[str]) -> list[str]:
    try:
        v = env.get(key)
        if v is None or not str(v).strip():
            return list(default)
        out = [p.strip() for p in str(v).split(",") if p.strip()]
        return out or list(default)
    except Exception:  # noqa: BLE001
        return list(default)


def _deps(env: dict, key: str) -> dict[str, str]:
    """Parse ``name=url,name=url`` dependency pings (FR-6). Empty -> no pings.

    Default is empty (fail-safe: no hardcoded network), the canonical example
    URLs live in ``.env.example`` so the operator opts in explicitly.
    """
    out: dict[str, str] = {}
    try:
        raw = env.get(key)
        if not raw or not str(raw).strip():
            return out
        for pair in str(raw).split(","):
            pair = pair.strip()
            if not pair or "=" not in pair:
                continue
            name, _, url = pair.partition("=")
            name, url = name.strip(), url.strip()
            if name and url:
                out[name] = url
    except Exception:  # noqa: BLE001
        return {}
    return out


@dataclass(frozen=True)
class Config:
    """Immutable sidecar config built from the environment (FR-10)."""

    # -- lifecycle / loop -------------------------------------------------
    enabled: bool = True
    interval_s: float = 30.0
    http_timeout_s: float = 5.0
    cooldown_s: float = 1800.0  # re-alert throttle for sustained signals

    # -- orchestrator /metrics -------------------------------------------
    metrics_url: str = "http://127.0.0.1:8500/metrics"
    orch_down_ticks: int = 3  # K consecutive failures before orch_down fires

    # -- host -------------------------------------------------------------
    mem_pct: float = 90.0
    disk_paths: list[str] = field(default_factory=lambda: ["/repos", "/app/data"])
    disk_crit_enabled: bool = False  # opt-in independent disk ceiling (D6)
    disk_crit_pct: float = 97.0

    # -- agents / queue / stages (derived from the /metrics envelope) -----
    agent_hung_min: float = 20.0  # minutes of runtime before "hung" is considered
    agent_cpu_floor: float = 0.01  # CPU fraction below which a long agent is "hung"
    stage_stuck_min: float = 120.0  # minutes a task may sit in one stage
    queue_depth: int = 20

    # -- containers (docker.sock, read-only) ------------------------------
    containers: list[str] = field(default_factory=lambda: ["orchestrator"])
    docker_sock: str = "/var/run/docker.sock"

    # -- external dependencies -------------------------------------------
    deps: dict[str, str] = field(default_factory=dict)

    # -- independent Telegram transport ----------------------------------
    tg_bot_token: str = ""
    tg_chat_id: str = ""

    # -- derived helpers --------------------------------------------------
    @property
    def agent_hung_s(self) -> float:
        return self.agent_hung_min * 60.0

    @property
    def stage_stuck_s(self) -> float:
        return self.stage_stuck_min * 60.0

    @classmethod
    def from_env(cls, env: dict | None = None) -> "Config":
        """Build a Config from ``env`` (defaults to ``os.environ``). never-raise."""
        e = dict(os.environ if env is None else env)
        return cls(
            enabled=_bool(e, "WATCHDOG_ENABLED", True),
            interval_s=_float(e, "WATCHDOG_INTERVAL_S", 30.0),
            http_timeout_s=_float(e, "WATCHDOG_HTTP_TIMEOUT_S", 5.0),
            cooldown_s=_float(e, "WATCHDOG_COOLDOWN_S", 1800.0),
            metrics_url=_str(e, "WATCHDOG_METRICS_URL", "http://127.0.0.1:8500/metrics"),
            orch_down_ticks=_int(e, "WATCHDOG_ORCH_DOWN_TICKS", 3),
            mem_pct=_float(e, "WATCHDOG_MEM_PCT", 90.0),
            disk_paths=_csv(e, "WATCHDOG_DISK_PATHS", ["/repos", "/app/data"]),
            disk_crit_enabled=_bool(e, "WATCHDOG_DISK_CRIT_ENABLED", False),
            disk_crit_pct=_float(e, "WATCHDOG_DISK_CRIT_PCT", 97.0),
            agent_hung_min=_float(e, "WATCHDOG_AGENT_HUNG_MIN", 20.0),
            agent_cpu_floor=_float(e, "WATCHDOG_AGENT_CPU_FLOOR", 0.01),
            stage_stuck_min=_float(e, "WATCHDOG_STAGE_STUCK_MIN", 120.0),
            queue_depth=_int(e, "WATCHDOG_QUEUE_DEPTH", 20),
            containers=_csv(e, "WATCHDOG_CONTAINERS", ["orchestrator"]),
            docker_sock=_str(e, "WATCHDOG_DOCKER_SOCK", "/var/run/docker.sock"),
            deps=_deps(e, "WATCHDOG_DEPS"),
            tg_bot_token=_str(e, "WATCHDOG_TG_BOT_TOKEN", ""),
            tg_chat_id=_str(e, "WATCHDOG_TG_CHAT_ID", ""),
        )