"""
knoe/core/ops/cloudnative_pg.py

Canonical Python owner for CloudNativePG lifecycle behavior.

Replaces etc/init_cloudnative_pg.sh runtime dispatch for the four active
call paths:

  initialize            -- install operator, apply cluster manifests, wait for readiness
  deploy                -- image-aware manifest apply + instance reconcile
  rollout               -- rolling restart via ordered pod deletion / promotion
  install_barman_plugin -- install the Barman Cloud operator plugin

Public API
----------
  ensure_operator(env, log, mode) -> None
  pin_controller(env, log, mode) -> None
  install_barman_plugin(env, log) -> None
  initialize(namespace, cluster_name, env, project_root, log, mode) -> None
  deploy(namespace, cluster_name, env, project_root, log, mode) -> None
  rollout(namespace, cluster_name, env, log) -> None
"""
from __future__ import annotations

import json
import logging
import subprocess
import time
from pathlib import Path
from typing import Callable

_LOG = logging.getLogger(__name__)
_LogFn = Callable[[str], None]

_CNPG_OPERATOR_FALLBACK_VERSION = "1.28.1"
_BARMAN_PLUGIN_FALLBACK_VERSION = "0.6.0"


# ---------------------------------------------------------------------------
# Internal helpers
# ---------------------------------------------------------------------------


def _log(log: _LogFn | None, msg: str) -> None:
    if log is not None:
        log(msg)
    else:
        _LOG.info(msg)


def _kubectl(
    args: list[str],
    env: dict | None = None,
    timeout: int = 30,
    check: bool = False,
) -> subprocess.CompletedProcess:
    return subprocess.run(
        ["kubectl"] + args,
        env=env,
        capture_output=True,
        text=True,
        timeout=timeout,
        check=check,
    )


def _kubectl_ok(args: list[str], env: dict | None = None, timeout: int = 15) -> bool:
    return _kubectl(args, env=env, timeout=timeout).returncode == 0


def _resolve_cnpg_manifest(project_root: str | Path, env: dict | None) -> Path:
    """Resolve the CNPG cluster manifest path, mirroring the shell K8S_PROLE_DIR logic."""
    if env:
        override = (env.get("CNPG_MANIFEST_OVERRIDE") or "").strip()
        if override:
            p = Path(override)
            if p.exists():
                return p
    root = Path(project_root)
    candidates = [
        root / "deploy" / "opentofu" / "k3s" / "manifests" / "prole" / "knoe-db.yaml",
        root / "k8s" / "prole" / "knoe-db.yaml",
    ]
    if env:
        prole_home = (env.get("PROLE_HOME") or "").strip()
        if prole_home:
            candidates.insert(0, Path(prole_home) / "k8s" / "prole" / "knoe-db.yaml")
    for candidate in candidates:
        if candidate.exists():
            return candidate
    return root / "k8s" / "prole" / "knoe-db.yaml"


def _apply_manifest(
    namespace: str,
    manifest: Path,
    env: dict | None,
    log: _LogFn | None,
    attempts: int = 8,
) -> None:
    """Apply a CNPG cluster manifest with retry on transient API errors."""
    if not manifest.exists():
        raise FileNotFoundError(f"CNPG manifest not found: {manifest}")
    _log(log, f"Applying CNPG manifest {manifest} in namespace {namespace}...")
    last_err = ""
    for i in range(1, attempts + 1):
        r = _kubectl(["-n", namespace, "apply", "-f", str(manifest)], env=env, timeout=60)
        if r.returncode == 0:
            if r.stdout.strip():
                _log(log, r.stdout.strip())
            return
        last_err = (r.stderr or r.stdout or "").strip()
        transient = any(
            kw in last_err.lower()
            for kw in ("etcdserver", "connection refused", "timeout", "tls handshake", "webhook")
        )
        if transient and i < attempts:
            _log(log, f"WARN: manifest apply failed (attempt {i}/{attempts}); retrying in 5s...")
            time.sleep(5)
            continue
        break
    raise RuntimeError(f"CNPG manifest apply failed after {attempts} attempts: {last_err}")


def _wait_pod_ready(
    namespace: str, pod: str, env: dict | None, timeout: int = 300, log: _LogFn | None = None
) -> None:
    r = _kubectl(
        ["-n", namespace, "wait", "--for=condition=Ready", f"pod/{pod}", f"--timeout={timeout}s"],
        env=env,
        timeout=timeout + 10,
    )
    if r.returncode != 0:
        _log(log, f"WARN: pod {pod} did not become Ready within {timeout}s")


def _wait_cnpg_pods(
    namespace: str,
    cluster_name: str,
    env: dict | None,
    timeout: int = 900,
    log: _LogFn | None = None,
) -> None:
    """Wait for all CNPG cluster pods to reach Ready state."""
    # Determine expected pod count from cluster spec
    r = _kubectl(
        ["-n", namespace, "get", "cluster", cluster_name, "-o", "jsonpath={.spec.instances}"],
        env=env,
        timeout=15,
    )
    target = 1
    if r.returncode == 0:
        try:
            target = max(1, int((r.stdout or "1").strip() or "1"))
        except ValueError:
            target = 1

    _log(log, f"Waiting for {target} CNPG pod(s) for cluster '{cluster_name}' in '{namespace}' (timeout={timeout}s)...")

    deadline = time.monotonic() + timeout
    last_feedback = 0.0
    while True:
        now = time.monotonic()
        if now >= deadline:
            raise RuntimeError(
                f"Timed out ({timeout}s) waiting for {target} CNPG pods to be Ready "
                f"in namespace '{namespace}'"
            )

        r2 = _kubectl(
            [
                "-n", namespace, "get", "pods",
                "-l", f"cnpg.io/cluster={cluster_name}",
                "-o",
                "jsonpath={range .items[*]}{.metadata.name}={.status.conditions[?(@.type==\"Ready\")].status}\\n{end}",
            ],
            env=env,
            timeout=15,
        )
        if r2.returncode == 0:
            lines = [l for l in (r2.stdout or "").splitlines() if "=" in l]
            ready = sum(1 for l in lines if l.split("=", 1)[1].strip() == "True")
            if ready >= target:
                _log(log, f"All {ready}/{target} CNPG pods are Ready.")
                return

            elapsed = timeout - (deadline - now)
            if elapsed - last_feedback >= 30:
                last_feedback = elapsed
                _log(log, f"  [{int(elapsed)}s/{timeout}s] {ready}/{target} CNPG pods ready...")

        time.sleep(5)


def _reconcile_instances(
    namespace: str,
    cluster_name: str,
    env: dict | None,
    log: _LogFn | None,
) -> None:
    """
    Cap CNPG cluster instances to the number of eligible schedulable nodes,
    then patch the cluster spec if the count has changed.

    Mirrors reconcile_cnpg_instances() from the shell script.
    """
    # Current spec instances
    r = _kubectl(
        ["-n", namespace, "get", "cluster", cluster_name, "-o", "jsonpath={.spec.instances}"],
        env=env, timeout=15,
    )
    if r.returncode != 0 or not (r.stdout or "").strip():
        return  # cluster may not exist yet
    try:
        current = max(0, int((r.stdout or "0").strip()))
    except ValueError:
        return

    desired_raw = int((env or {}).get("CNPG_INSTANCES", "3") or "3")
    desired = max(1, desired_raw)

    # Count eligible nodes (nodes with cnpg.io/node-role=db or all schedulable nodes)
    node_selector = (env or {}).get("CNPG_NODE_SELECTOR", "")
    if node_selector:
        r2 = _kubectl(["get", "nodes", "-l", node_selector, "--no-headers"], env=env, timeout=10)
    else:
        r2 = _kubectl(["get", "nodes", "--no-headers"], env=env, timeout=10)
    eligible = len([l for l in (r2.stdout or "").splitlines() if l.strip()]) if r2.returncode == 0 else 1
    eligible = max(1, eligible)

    if desired > eligible:
        desired = eligible

    if current == desired:
        return

    # Clamp maxSyncReplicas so the spec stays valid (maxSyncReplicas < instances)
    base_max_sync = int((env or {}).get("CNPG_MAX_SYNC_REPLICAS", "1") or "1")
    if desired <= 1:
        max_sync = 0
    else:
        max_sync = min(base_max_sync, desired - 1)

    _log(log, f"Reconciling CNPG instances: {current} → {desired} (eligible_nodes={eligible})")
    patch = json.dumps({"spec": {"instances": desired, "maxSyncReplicas": max_sync}})
    for attempt in range(1, 9):
        r3 = _kubectl(
            ["-n", namespace, "patch", "cluster", cluster_name, "--type", "merge", "-p", patch],
            env=env, timeout=30,
        )
        if r3.returncode == 0:
            _log(log, f"Cluster instances patched to {desired}.")
            return
        err = (r3.stderr or r3.stdout or "").strip().lower()
        transient = any(kw in err for kw in ("etcd", "connection refused", "timeout", "webhook"))
        if transient and attempt < 8:
            _log(log, f"WARN: patch failed (attempt {attempt}/8); retrying in 5s...")
            time.sleep(5)
        else:
            _log(log, f"WARN: could not patch CNPG instances: {err}")
            return


# ---------------------------------------------------------------------------
# Public API
# ---------------------------------------------------------------------------


def ensure_operator(
    env: dict | None = None,
    log: _LogFn | None = None,
    mode: str = "",
) -> None:
    """Install the CloudNativePG operator if not already present, then wait for readiness."""
    if _kubectl_ok(["-n", "cnpg-system", "get", "deploy", "cnpg-controller-manager"], env=env):
        _log(log, "CloudNative-PG operator already installed; waiting for readiness...")
        _kubectl(["-n", "cnpg-system", "rollout", "status", "deploy/cnpg-controller-manager", "--timeout=180s"], env=env, timeout=190)
        if mode == "k3s":
            _tune_operator_for_k3s(env, log)
            _kubectl(["-n", "cnpg-system", "rollout", "status", "deploy/cnpg-controller-manager", "--timeout=300s"], env=env, timeout=310)
        return

    version = ""
    if env:
        version = (env.get("CNPG_OPERATOR_VERSION") or env.get("CNPG_VERSION") or "").strip()
    if not version or version == "latest":
        version = _CNPG_OPERATOR_FALLBACK_VERSION

    minor = ".".join(version.split(".")[:2])
    url = (
        f"https://raw.githubusercontent.com/cloudnative-pg/cloudnative-pg"
        f"/release-{minor}/releases/cnpg-{version}.yaml"
    )
    _log(log, f"Installing CloudNative-PG operator version {version}...")
    r = _kubectl(["apply", "--server-side", "-f", url], env=env, timeout=120)
    if r.returncode != 0:
        raise RuntimeError(f"Failed to install CNPG operator: {(r.stderr or r.stdout or '').strip()}")

    if _kubectl_ok(["-n", "cnpg-system", "get", "deploy", "cnpg-controller-manager"], env=env, timeout=20):
        _kubectl(["-n", "cnpg-system", "rollout", "status", "deploy/cnpg-controller-manager", "--timeout=180s"], env=env, timeout=190)
        if mode == "k3s":
            _tune_operator_for_k3s(env, log)
            _kubectl(["-n", "cnpg-system", "rollout", "status", "deploy/cnpg-controller-manager", "--timeout=300s"], env=env, timeout=310)


def _tune_operator_for_k3s(env: dict | None, log: _LogFn | None) -> None:
    """Relax CNPG controller probes/resources for single-node k3s environments."""
    _log(log, "Tuning CNPG operator deployment probes/resources for k3s...")
    patch = json.dumps({
        "spec": {
            "template": {
                "spec": {
                    "containers": [
                        {
                            "name": "manager",
                            "resources": {
                                "requests": {"cpu": "250m", "memory": "512Mi"},
                                "limits": {"cpu": "500m", "memory": "1Gi"},
                            },
                            "livenessProbe": {"timeoutSeconds": 5, "failureThreshold": 6},
                            "readinessProbe": {"timeoutSeconds": 5, "failureThreshold": 6},
                            "startupProbe": {"timeoutSeconds": 5, "failureThreshold": 60},
                        }
                    ]
                }
            }
        }
    })
    _kubectl(
        ["-n", "cnpg-system", "patch", "deploy", "cnpg-controller-manager", "--type", "merge", "-p", patch],
        env=env, timeout=30,
    )


def pin_controller(
    env: dict | None = None,
    log: _LogFn | None = None,
    mode: str = "",
) -> None:
    """Pin the CNPG controller manager to storage-designated nodes (k3s) or as configured."""
    selector = (env or {}).get("CNPG_CONTROLLER_NODE_SELECTOR", "").strip()

    if not selector and mode == "k3s":
        r = _kubectl(["get", "nodes", "-l", "storage=primary", "--no-headers"], env=env, timeout=10)
        if r.returncode == 0 and (r.stdout or "").strip():
            selector = "storage=primary"
        else:
            r2 = _kubectl(
                ["get", "nodes", "-l", "node-role.kubernetes.io/control-plane",
                 "-o", "jsonpath={.items[0].metadata.name}"],
                env=env, timeout=10,
            )
            if r2.returncode == 0 and (r2.stdout or "").strip():
                selector = f"kubernetes.io/hostname={r2.stdout.strip()}"

    if not selector:
        return

    if "=" not in selector:
        _log(log, f"WARN: CNPG_CONTROLLER_NODE_SELECTOR must be key=value (got '{selector}'). Skipping pin.")
        return

    key, value = selector.split("=", 1)
    if not _kubectl_ok(["get", "nodes", "-l", f"{key}={value}", "--no-headers"], env=env):
        _log(log, f"WARN: No nodes match CNPG_CONTROLLER_NODE_SELECTOR={selector}. Skipping pin.")
        return

    _log(log, f"Pinning cnpg-controller-manager to nodes with {selector}...")
    patch = json.dumps({"spec": {"template": {"spec": {"nodeSelector": {key: value}}}}})
    _kubectl(
        ["-n", "cnpg-system", "patch", "deployment", "cnpg-controller-manager",
         "--type", "merge", "-p", patch],
        env=env, timeout=30,
    )


def install_barman_plugin(
    env: dict | None = None,
    log: _LogFn | None = None,
) -> None:
    """Install the Barman Cloud operator plugin, retrying on cert-manager webhook errors."""
    url = ((env or {}).get("BARMAN_PLUGIN_MANIFEST_URL") or "").strip()
    if not url:
        tag = _resolve_barman_plugin_tag(env, log)
        url = f"https://github.com/cloudnative-pg/plugin-barman-cloud/releases/download/{tag}/manifest.yaml"

    _log(log, f"Installing Barman Cloud plugin from {url}...")
    r = subprocess.run(
        ["kubectl", "apply", "-f", url],
        env=env, capture_output=True, text=True, timeout=120,
    )
    if r.returncode != 0:
        combined = (r.stdout or "") + (r.stderr or "")
        if "webhook.cert-manager.io" in combined.lower() or "cert-manager" in combined.lower():
            _log(log, "WARN: cert-manager webhook error; restarting cert-manager and retrying...")
            for deploy in ["cert-manager", "cert-manager-webhook", "cert-manager-cainjector"]:
                _kubectl(["-n", "cert-manager", "rollout", "restart", f"deploy/{deploy}"], env=env, timeout=30)
            _kubectl(["-n", "cert-manager", "rollout", "status", "deploy/cert-manager-webhook", "--timeout=180s"], env=env, timeout=190)
            _kubectl(["-n", "cert-manager", "rollout", "status", "deploy/cert-manager", "--timeout=180s"], env=env, timeout=190)
            r2 = subprocess.run(
                ["kubectl", "apply", "-f", url],
                env=env, capture_output=True, text=True, timeout=120,
            )
            if r2.returncode != 0:
                raise RuntimeError(
                    f"Failed to apply Barman Cloud plugin after cert-manager restart: "
                    f"{(r2.stderr or r2.stdout or '').strip()}"
                )
        else:
            raise RuntimeError(
                f"Failed to apply Barman Cloud plugin manifest: {(r.stderr or r.stdout or '').strip()}"
            )
    elif r.stdout.strip():
        _log(log, r.stdout.strip())

    # Wait for barman-cloud deployment if it was created
    r3 = _kubectl(["-n", "cnpg-system", "get", "deploy", "barman-cloud"], env=env, timeout=15)
    if r3.returncode == 0:
        timeout_s = int((env or {}).get("BARMAN_DEPLOY_TIMEOUT", "300") or "300")
        _kubectl(
            ["-n", "cnpg-system", "rollout", "status", "deploy/barman-cloud", f"--timeout={timeout_s}s"],
            env=env, timeout=timeout_s + 10,
        )


def _resolve_barman_plugin_tag(env: dict | None, log: _LogFn | None) -> str:
    """Fetch the latest Barman Cloud plugin release tag from GitHub, with fallback."""
    fallback = ((env or {}).get("BARMAN_PLUGIN_FALLBACK_VERSION") or _BARMAN_PLUGIN_FALLBACK_VERSION).strip()
    try:
        import urllib.request as _req
        import json as _json
        with _req.urlopen(
            "https://api.github.com/repos/cloudnative-pg/plugin-barman-cloud/releases/latest",
            timeout=10,
        ) as resp:
            data = _json.loads(resp.read())
            tag = (data.get("tag_name") or "").strip()
            if tag and tag != "null":
                return tag
    except Exception as exc:
        _log(log, f"WARN: could not fetch latest Barman plugin version: {exc}; using v{fallback}")
    return f"v{fallback}"


def initialize(
    namespace: str,
    cluster_name: str,
    env: dict | None = None,
    project_root: str | Path = ".",
    log: _LogFn | None = None,
    mode: str = "",
) -> None:
    """
    Full CNPG initialization pipeline.

    Steps (matching init_cloudnative_pg.sh initialize):
      1. Ensure the CNPG operator is installed and ready
      2. Pin the controller to storage nodes (k3s)
      3. Install the Barman Cloud plugin
      4. Preflight: verify required secrets exist
      5. Apply the CNPG cluster manifest
      6. Wait for cluster pods to become Ready
    """
    _log(log, f"Initializing CNPG cluster '{cluster_name}' in namespace '{namespace}'...")

    ensure_operator(env=env, log=log, mode=mode)
    pin_controller(env=env, log=log, mode=mode)
    install_barman_plugin(env=env, log=log)

    # Preflight: required secrets must exist before applying the cluster
    missing = []
    for secret in ["knoe-db-user", f"{cluster_name}-tls", f"{cluster_name}-ca"]:
        if not _kubectl_ok(["-n", namespace, "get", "secret", secret], env=env):
            missing.append(secret)
    if missing:
        raise RuntimeError(
            f"Required secrets missing in namespace '{namespace}': {', '.join(missing)}. "
            "The CNPG cluster cannot start without these secrets."
        )
    _log(log, "Pre-flight check passed: all required secrets present.")

    manifest = _resolve_cnpg_manifest(project_root, env)
    _apply_manifest(namespace, manifest, env, log)

    wait_timeout = int((env or {}).get("CNPG_WAIT_TIMEOUT", "900") or "900")
    _wait_cnpg_pods(namespace, cluster_name, env, timeout=wait_timeout, log=log)

    _log(log, f"Initialization complete for CNPG cluster '{cluster_name}'.")


def deploy(
    namespace: str,
    cluster_name: str,
    env: dict | None = None,
    project_root: str | Path = ".",
    log: _LogFn | None = None,
    mode: str = "",
) -> None:
    """
    Image-aware CNPG deploy pipeline.

    Steps (matching init_cloudnative_pg.sh deploy_cluster):
      1. Ensure the CNPG operator is installed and ready
      2. Pin the controller to storage nodes (k3s)
      3. Install the Barman Cloud plugin
      4. Apply the CNPG cluster manifest
      5. Reconcile instance count to match eligible node count
    """
    _log(log, f"Deploying CNPG cluster '{cluster_name}' in namespace '{namespace}'...")

    ensure_operator(env=env, log=log, mode=mode)
    pin_controller(env=env, log=log, mode=mode)
    install_barman_plugin(env=env, log=log)

    manifest = _resolve_cnpg_manifest(project_root, env)
    _apply_manifest(namespace, manifest, env, log)
    _reconcile_instances(namespace, cluster_name, env, log)

    _log(log, f"Deploy complete for CNPG cluster '{cluster_name}'.")


def rollout(
    namespace: str,
    cluster_name: str,
    env: dict | None = None,
    log: _LogFn | None = None,
) -> None:
    """
    Rolling restart of a CNPG cluster via ordered pod deletion.

    Steps (matching init_cloudnative_pg.sh rollout_cluster):
      1. Identify the current primary pod
      2. Delete replica pods one-by-one, waiting for readiness
      3. Promote a replica to primary (if kubectl-cnpg plugin is available)
      4. Delete and recreate the old primary pod
    """
    _log(log, f"Starting rollout for CNPG cluster '{cluster_name}' in namespace '{namespace}'...")

    # Identify current primary
    r = _kubectl(
        ["-n", namespace, "get", "cluster", cluster_name, "-o", "jsonpath={.status.currentPrimary}"],
        env=env, timeout=15,
    )
    primary = (r.stdout or "").strip()
    if not primary:
        raise RuntimeError(f"Could not identify primary instance for cluster '{cluster_name}'")
    _log(log, f"Primary instance: {primary}")

    # List all cluster pods
    r2 = _kubectl(
        ["-n", namespace, "get", "pods", "-l", f"cnpg.io/cluster={cluster_name}",
         "-o", "jsonpath={.items[*].metadata.name}"],
        env=env, timeout=15,
    )
    pods = (r2.stdout or "").strip().split()
    if not pods:
        raise RuntimeError(f"No pods found for cluster '{cluster_name}'")

    has_plugin = _kubectl_ok(["cnpg", "version"], env=env, timeout=10)

    # Delete non-primary pods first
    new_primary: str | None = None
    for pod in pods:
        if pod == primary:
            continue
        _log(log, f"Recreating non-primary pod: {pod}...")
        _kubectl(["-n", namespace, "delete", "pod", pod], env=env, timeout=60)
        _wait_pod_ready(namespace, pod, env, timeout=300, log=log)
        if new_primary is None:
            new_primary = pod

    # Promote a replica if the cnpg plugin is available
    if new_primary and has_plugin:
        _log(log, f"Promoting {new_primary}...")
        _kubectl(["cnpg", "promote", cluster_name, new_primary, "-n", namespace], env=env, timeout=30)
        deadline = time.monotonic() + 300
        while time.monotonic() < deadline:
            r3 = _kubectl(
                ["-n", namespace, "get", "cluster", cluster_name,
                 "-o", "jsonpath={.status.currentPrimary}"],
                env=env, timeout=10,
            )
            if (r3.stdout or "").strip() == new_primary:
                _log(log, f"{new_primary} is now the primary.")
                break
            time.sleep(5)
    elif new_primary and not has_plugin:
        _log(log, "WARN: kubectl cnpg plugin not available; skipping explicit promotion.")

    # Delete the old primary last
    _log(log, f"Recreating old primary pod: {primary}...")
    _kubectl(["-n", namespace, "delete", "pod", "-n", namespace, primary], env=env, timeout=60)
    _wait_pod_ready(namespace, primary, env, timeout=300, log=log)

    if has_plugin:
        _log(log, "Rollout complete. Final cluster status:")
        _kubectl(["cnpg", "status", cluster_name, "-n", namespace], env=env, timeout=30)
    else:
        _log(log, "Rollout complete.")