from __future__ import annotations

import re

from checks.base import Check
from state import make_key


class ZFSCheck(Check):
    def run(self) -> None:
        for pool in self.config.zfs.pools:
            self.log.info("--- Pool: %s ---", pool)
            self._check_pool(pool)

    def get_pool_disks(self, pool: str) -> list[str]:
        """Return normalized block device paths for all disks in a pool."""
        out = self._run(
            ["zpool", "status", "-P", pool],
            timeout=self.config.zfs.timeout,
        )
        if not out:
            return []

        disks: list[str] = []
        for line in out.splitlines():
            m = re.match(r"\s+(/dev/\S+)", line)
            if m:
                dev = _normalize_device(m.group(1))
                if dev not in disks:
                    disks.append(dev)
        return disks

    # ── Pool checks ───────────────────────────────────────────

    def _check_pool(self, pool: str) -> None:
        key_missing = make_key("pool_miss", pool)
        key_health  = make_key("pool_hlth", pool)
        key_errors  = make_key("pool_err",  pool)
        key_cap     = make_key("pool_cap",  pool)

        # Erreichbarkeit
        out = self._run(
            ["zpool", "list", pool],
            timeout=self.config.zfs.timeout,
        )
        if out is None:
            if self.alerter.should_alert(key_missing, "CRITICAL"):
                self.alerter.send_alert(
                    "CRITICAL",
                    f"Pool verschwunden: {pool}",
                    f"Pool <code>{pool}</code> ist nicht mehr importiert!\n\n"
                    f"<code>zpool import\nzpool status</code>",
                    key_missing,
                )
            return
        else:
            if self.alerter.clear_alert(key_missing):
                self.alerter.send_alert(
                    "INFO",
                    f"Pool wieder erreichbar: {pool}",
                    f"Pool <code>{pool}</code> ist wieder da ✅",
                )

        # Health
        health = (
            self._run(
                ["zpool", "list", "-H", "-o", "health", pool],
                timeout=self.config.zfs.timeout,
            ) or ""
        ).strip()

        if health != "ONLINE":
            self.state.set(f"{key_health}_last", health)
            if self.alerter.should_alert(key_health, "CRITICAL"):
                details = self._pool_status_summary(pool)
                self.alerter.send_alert(
                    "CRITICAL",
                    f"Pool {pool}: {health}!",
                    f"Pool <code>{pool}</code> ist <b>{health}</b>!\n\n"
                    f"<pre>{details}</pre>\n"
                    f"<code>zpool status -v {pool}</code>",
                    key_health,
                )
        else:
            self.state.set(f"{key_health}_last", "ONLINE")
            if self.alerter.clear_alert(key_health):
                self.alerter.send_alert(
                    "INFO",
                    f"Pool {pool}: wieder ONLINE ✅",
                    f"Pool <code>{pool}</code> ist wieder gesund.",
                )

        # I/O Errors
        err_lines = self._parse_io_errors(pool)
        if err_lines:
            if self.alerter.should_alert(key_errors, "WARNING"):
                self.alerter.send_alert(
                    "WARNING",
                    f"Pool {pool}: I/O Fehler!",
                    f"Pool <code>{pool}</code> hat Fehler auf Disks:\n\n"
                    f"<pre>{err_lines}</pre>\n"
                    f"→ <code>zpool scrub {pool}</code>",
                    key_errors,
                )
        else:
            if self.alerter.clear_alert(key_errors):
                self.alerter.send_alert(
                    "INFO",
                    f"Pool {pool}: I/O Fehler behoben ✅",
                    f"Keine I/O Fehler mehr in Pool <code>{pool}</code>.",
                )

        # Kapazität
        cap_str = (
            self._run(
                ["zpool", "list", "-H", "-o", "cap", pool],
                timeout=self.config.zfs.timeout,
            ) or "0"
        ).strip().rstrip("%")
        cap = int(cap_str) if cap_str.isdigit() else 0

        if cap >= self.config.zfs.crit_pct:
            if self.alerter.should_alert(key_cap, "CRITICAL"):
                self.alerter.send_alert(
                    "CRITICAL",
                    f"Pool {pool}: {cap}% voll!",
                    f"Pool <code>{pool}</code> ist zu <b>{cap}%</b> voll!\n"
                    f"Sofort Platz schaffen – ZFS braucht freien Raum!",
                    key_cap,
                )
        elif cap >= self.config.zfs.warn_pct:
            if self.alerter.should_alert(key_cap, "WARNING"):
                self.alerter.send_alert(
                    "WARNING",
                    f"Pool {pool}: {cap}% voll",
                    f"Pool <code>{pool}</code> ist zu <b>{cap}%</b> voll.",
                    key_cap,
                )
        else:
            if self.alerter.clear_alert(key_cap):
                self.alerter.send_alert(
                    "INFO",
                    f"Pool {pool}: Füllstand OK",
                    f"Pool <code>{pool}</code> ist wieder unter "
                    f"{self.config.zfs.warn_pct}% ✅",
                )

        self.log.info("Pool %s: health=%s cap=%d%%", pool, health, cap)

    def _pool_status_summary(self, pool: str) -> str:
        out = self._run(["zpool", "status", pool], timeout=self.config.zfs.timeout) or ""
        lines = [
            l for l in out.splitlines()
            if re.search(r"state:|status:|action:|DEGRADED|FAULTED|REMOVED|UNAVAIL", l)
        ]
        return "\n".join(lines[:10])

    def _parse_io_errors(self, pool: str) -> str:
        out = self._run(
            ["zpool", "status", "-P", pool],
            timeout=self.config.zfs.timeout,
        ) or ""
        lines = []
        for line in out.splitlines():
            m = re.match(r"\s+(/dev/\S+)\s+\S+\s+(\d+)\s+(\d+)\s+(\d+)", line)
            if m:
                dev, r, w, c = m.group(1), int(m.group(2)), int(m.group(3)), int(m.group(4))
                if r or w or c:
                    lines.append(f"{dev}  R:{r} W:{w} C:{c}")
        return "\n".join(lines)


# ── Device Normalisierung ─────────────────────────────────────

def _normalize_device(dev: str) -> str:
    import os
    resolved = os.path.realpath(dev)
    # nvme0n1p1 → nvme0n1
    resolved = re.sub(r"(nvme\d+n\d+)p\d+$", r"\1", resolved)
    # sda1 → sda
    resolved = re.sub(r"(sd[a-z]+)\d+$", r"\1", resolved)
    return resolved