from __future__ import annotations

import json
import os
import tempfile
import time

from ._services_common import _LogFn, _detect_mode, _helm, _kubectl, _log, _namespace, _to_bool


def _monitoring_namespace(namespace: str | None, env: dict | None) -> str:
    if env:
        explicit = str(env.get("MONITORING_NAMESPACE") or "").strip()
        if explicit:
            return explicit
    return _namespace(namespace, env, default="monitoring")


def _release_name(env: dict | None) -> str:
    return str((env or {}).get("MONITORING_RELEASE") or "prometheus")


def _is_app_cluster_context(env: dict | None) -> bool:
    app_ctx = str((env or {}).get("APP_CLUSTER_KUBECONTEXT") or "").strip()
    current_ctx = str((env or {}).get("KUBECONTEXT") or "").strip()
    if not app_ctx:
        return True
    if not current_ctx:
        return False
    return current_ctx == app_ctx


def _helm_status_value(release: str, namespace: str, env: dict | None) -> str:
    res = _helm(["status", release, "-n", namespace, "-o", "json"], env=env, timeout=60)
    if res.returncode != 0:
        return ""
    try:
        data = json.loads(res.stdout or "{}")
    except json.JSONDecodeError:
        return ""
    return str(((data.get("info") or {}).get("status") or "")).strip().lower()


def _helm_history_json(release: str, namespace: str, env: dict | None) -> list[dict]:
    res = _helm(["history", release, "-n", namespace, "-o", "json"], env=env, timeout=60)
    if res.returncode != 0:
        return []
    try:
        data = json.loads(res.stdout or "[]")
    except json.JSONDecodeError:
        return []
    if isinstance(data, list):
        return [entry for entry in data if isinstance(entry, dict)]
    return []


def _helm_history_text(release: str, namespace: str, env: dict | None) -> str:
    res = _helm(["history", release, "-n", namespace], env=env, timeout=60)
    return (res.stdout or "").strip()


def _revision_number(entry: dict) -> int:
    try:
        return int(str(entry.get("revision") or "").strip())
    except (TypeError, ValueError):
        return -1


def _latest_history_entry(entries: list[dict]) -> dict | None:
    if not entries:
        return None
    return max(entries, key=_revision_number)


def _latest_pending_status(entries: list[dict]) -> tuple[str, int]:
    latest = _latest_history_entry(entries) or {}
    latest_status = str(latest.get("status") or "").strip().lower()
    latest_revision = _revision_number(latest)
    return latest_status, latest_revision


def _last_deployed_revision(entries: list[dict]) -> int:
    deployed_revs = [_revision_number(entry) for entry in entries if str(entry.get("status") or "").strip().lower() == "deployed"]
    deployed_revs = [rev for rev in deployed_revs if rev > 0]
    if not deployed_revs:
        return -1
    return max(deployed_revs)


def _recover_stale_prometheus_helm_lock(
    *,
    release: str,
    namespace: str,
    env: dict | None,
    log: _LogFn | None,
) -> bool:
    pending_statuses = {"pending-install", "pending-upgrade", "pending-rollback"}
    status = _helm_status_value(release, namespace, env)
    history_entries = _helm_history_json(release, namespace, env)
    latest_status, latest_revision = _latest_pending_status(history_entries)

    if latest_status not in pending_statuses:
        return False

    if status and status != latest_status:
        _log(
            log,
            f"[MONITORING] Helm release {release} latest history={latest_status} but current status={status}; treating as progressing, skipping stale-lock recovery.",
        )
        return False

    poll_count = 2
    poll_sleep_seconds = 30
    _log(
        log,
        f"[MONITORING] Detected pending Helm state for {release}: status={latest_status} rev={latest_revision}. Verifying stability over {poll_count} poll(s) / {poll_count * poll_sleep_seconds}s.",
    )

    for poll in range(1, poll_count + 1):
        time.sleep(poll_sleep_seconds)
        polled_entries = _helm_history_json(release, namespace, env)
        polled_status, polled_revision = _latest_pending_status(polled_entries)
        _log(
            log,
            f"[MONITORING] Helm stale-lock poll {poll}/{poll_count}: latest status={polled_status or '<none>'} rev={polled_revision}.",
        )
        if polled_status not in pending_statuses:
            _log(log, f"[MONITORING] Helm release {release} left pending state during verification; not stale.")
            return False
        if polled_status != latest_status or polled_revision != latest_revision:
            _log(
                log,
                f"[MONITORING] Helm release {release} pending state changed during verification; treating as actively progressing.",
            )
            return False

    last_deployed_revision = _last_deployed_revision(history_entries)
    if last_deployed_revision <= 0:
        history_text = _helm_history_text(release, namespace, env)
        raise RuntimeError(
            "REPAIR_BLOCKED: stale Helm lock detected for "
            f"release '{release}' in namespace '{namespace}' (latest status={latest_status}, revision={latest_revision}), "
            "but no prior deployed revision exists.\n"
            f"helm history output:\n{history_text or '<empty>'}"
        )

    _log(
        log,
        f"[MONITORING] Recovering stale Helm lock for {release}: rolling back to deployed revision {last_deployed_revision}.",
    )
    _helm(
        ["rollback", release, str(last_deployed_revision), "-n", namespace],
        env=env,
        timeout=600,
        check=True,
    )
    post_rollback_status = _helm_status_value(release, namespace, env)
    if post_rollback_status != "deployed":
        raise RuntimeError(
            "REPAIR_BLOCKED: Helm rollback did not restore deployed state for "
            f"release '{release}' in namespace '{namespace}' (status={post_rollback_status or '<unknown>'})."
        )
    _log(log, f"[MONITORING] Helm stale-lock recovery succeeded for {release}; status is deployed.")
    return True


def initialize(
    *,
    namespace: str | None = None,
    env: dict | None = None,
    log: _LogFn | None = None,
    mode: str | None = None,
) -> None:
    update(namespace=namespace, env=env, log=log, mode=mode)


def start(
    *,
    namespace: str | None = None,
    env: dict | None = None,
    log: _LogFn | None = None,
    mode: str | None = None,
) -> None:
    update(namespace=namespace, env=env, log=log, mode=mode)


def _values_yaml_k8s(grafana_password: str) -> str:
    """Helm values for GKE / cloud-managed Kubernetes (no local PV affinity)."""
    return (
        "prometheus:\n"
        "  prometheusSpec:\n"
        "    storageSpec:\n"
        "      volumeClaimTemplate:\n"
        "        spec:\n"
        "          storageClassName: standard\n"
        "          accessModes: [ReadWriteOnce]\n"
        "          resources:\n"
        "            requests:\n"
        "              storage: 10Gi\n"
        "alertmanager:\n"
        "  alertmanagerSpec:\n"
        "    storage:\n"
        "      volumeClaimTemplate:\n"
        "        spec:\n"
        "          storageClassName: standard\n"
        "          accessModes: [ReadWriteOnce]\n"
        "          resources:\n"
        "            requests:\n"
        "              storage: 5Gi\n"
        "grafana:\n"
        "  adminUser: admin\n"
        f"  adminPassword: {grafana_password}\n"
        "  persistence:\n"
        "    type: sts\n"
        "    enabled: true\n"
        "    storageClassName: standard\n"
        "    accessModes: [ReadWriteOnce]\n"
        "    size: 5Gi\n"
    )


def _values_yaml_k3d(grafana_password: str, env: dict | None) -> str:
    """Helm values for k3d local dev cluster (local-path storage, no node affinity)."""
    sc = str((env or {}).get("MONITORING_STORAGE_CLASS") or "local-path")
    return (
        "grafana:\n"
        "  adminUser: admin\n"
        f"  adminPassword: {grafana_password}\n"
        "  persistence:\n"
        "    type: sts\n"
        "    enabled: true\n"
        f"    storageClassName: {sc}\n"
        "    accessModes: [ReadWriteOnce]\n"
        "    size: 10Gi\n"
        "prometheus:\n"
        "  prometheusSpec:\n"
        "    storageSpec:\n"
        "      volumeClaimTemplate:\n"
        "        spec:\n"
        f"          storageClassName: {sc}\n"
        "          accessModes: [ReadWriteOnce]\n"
        "          resources:\n"
        "            requests:\n"
        "              storage: 10Gi\n"
        "alertmanager:\n"
        "  alertmanagerSpec:\n"
        "    storage:\n"
        "      volumeClaimTemplate:\n"
        "        spec:\n"
        f"          storageClassName: {sc}\n"
        "          accessModes: [ReadWriteOnce]\n"
        "          resources:\n"
        "            requests:\n"
        "              storage: 2Gi\n"
    )


def _values_yaml_k3s(grafana_password: str, env: dict | None) -> str:
    """Helm values for k3s homelab (local iSCSI PVs pinned to merlin.knoe.org)."""
    data_dir = str((env or {}).get("PROLE_MONITORING_DATA_DIR") or "/synology/d004").rstrip("/")
    volume_id = os.path.basename(data_dir)  # e.g. "d004"
    sc_prom = f"merlin-local-iscsi-{volume_id}-prometheus"
    sc_alert = f"merlin-local-iscsi-{volume_id}-alertmanager"
    sc_grafana = f"merlin-local-iscsi-{volume_id}-grafana"

    monitoring_node = str((env or {}).get("MONITORING_PRIMARY_NODE") or "merlin.prole.org")
    excluded_nodes = str((env or {}).get("MONITORING_NODE_EXPORTER_EXCLUDE_NODES") or "pi.knoe.org")
    excluded_list = [n.strip() for n in excluded_nodes.split(",") if n.strip()]

    node_affinity_yaml = (
        "    affinity:\n"
        "      nodeAffinity:\n"
        "        requiredDuringSchedulingIgnoredDuringExecution:\n"
        "          nodeSelectorTerms:\n"
        "          - matchExpressions:\n"
        "            - key: kubernetes.io/hostname\n"
        "              operator: In\n"
        "              values:\n"
        f"              - {monitoring_node}\n"
    )

    values = "prometheus-node-exporter:\n"
    if excluded_list:
        values += (
            "  affinity:\n"
            "    nodeAffinity:\n"
            "      requiredDuringSchedulingIgnoredDuringExecution:\n"
            "        nodeSelectorTerms:\n"
            "        - matchExpressions:\n"
            "          - key: kubernetes.io/hostname\n"
            "            operator: NotIn\n"
            "            values:\n"
        )
        for node in excluded_list:
            values += f"            - {node}\n"

    values += (
        "prometheus:\n"
        "  prometheusSpec:\n"
        + node_affinity_yaml
        + "    storageSpec:\n"
        "      volumeClaimTemplate:\n"
        "        spec:\n"
        f"          storageClassName: {sc_prom}\n"
        "          accessModes: [ReadWriteOnce]\n"
        "          resources:\n"
        "            requests:\n"
        "              storage: 30Gi\n"
    )
    values += (
        "alertmanager:\n"
        "  alertmanagerSpec:\n"
        + node_affinity_yaml
        + "    storage:\n"
        "      volumeClaimTemplate:\n"
        "        spec:\n"
        f"          storageClassName: {sc_alert}\n"
        "          accessModes: [ReadWriteOnce]\n"
        "          resources:\n"
        "            requests:\n"
        "              storage: 5Gi\n"
    )
    values += (
        "grafana:\n"
        "  adminUser: admin\n"
        f"  adminPassword: {grafana_password}\n"
        "  persistence:\n"
        "    type: sts\n"
        "    enabled: true\n"
        f"    storageClassName: {sc_grafana}\n"
        "    accessModes: [ReadWriteOnce]\n"
        "    size: 10Gi\n"
    )
    return values


def _purge_broken_monitoring(ns: str, release: str, env: dict | None, log: _LogFn | None) -> None:
    """Uninstall a broken monitoring release and delete only its unbound (Pending) PVCs.

    Bound PVCs are left intact so that any pod that came up after a prior timeout
    can still access its data on the next install, and to avoid wiping working state.
    """
    _log(log, f"[MONITORING] Purging broken {release} release in {ns}")
    _helm(["uninstall", release, "-n", ns], env=env, timeout=300)
    pvc_res = _kubectl(["-n", ns, "get", "pvc", "--no-headers"], env=env, timeout=30)
    for line in (pvc_res.stdout or "").splitlines():
        parts = line.split()
        if len(parts) >= 2 and parts[1] == "Pending":
            pvc_name = parts[0].strip()
            _log(log, f"[MONITORING] Deleting unbound PVC {pvc_name}")
            _kubectl(["-n", ns, "delete", f"pvc/{pvc_name}", "--ignore-not-found=true"], env=env, timeout=60)


def update(
    *,
    namespace: str | None = None,
    env: dict | None = None,
    log: _LogFn | None = None,
    mode: str | None = None,
) -> None:
    effective_mode = _detect_mode(mode, env)
    ns = _monitoring_namespace(namespace, env)
    release = _release_name(env)
    chart = str((env or {}).get("MONITORING_CHART") or "prometheus-community/kube-prometheus-stack")
    grafana_password = str((env or {}).get("GRAFANA_ADMIN_PASSWORD") or "knoe")

    _log(log, "[MONITORING] Ensuring helm repos")
    _helm(["repo", "add", "prometheus-community", "https://prometheus-community.github.io/helm-charts"], env=env)
    _helm(["repo", "update"], env=env)

    _kubectl(["create", "namespace", ns], env=env, timeout=60)

    if effective_mode == "k8s":
        values_yaml = _values_yaml_k8s(grafana_password)
    elif effective_mode == "k3d":
        values_yaml = _values_yaml_k3d(grafana_password, env)
    else:
        # k3s: homelab local-PV setup pinned to merlin.knoe.org
        values_yaml = _values_yaml_k3s(grafana_password, env)

    # Detect broken state: Helm release is "failed" AND there are unbound PVCs.
    # Gating on "failed" (not just Pending pods) avoids purging a still-converging
    # install or a release that timed out but whose pods eventually came up.
    helm_status = _helm_status_value(release, ns, env)
    if helm_status == "failed":
        pvcs_res = _kubectl(["-n", ns, "get", "pvc", "--no-headers"], env=env, timeout=30)
        has_unbound_pvcs = any(
            len(ln.split()) >= 2 and ln.split()[1] == "Pending"
            for ln in (pvcs_res.stdout or "").splitlines()
            if ln.strip()
        )
        if has_unbound_pvcs:
            _log(log, f"[MONITORING] Helm release {release} is failed with unbound PVCs in {ns}; purging.")
            _purge_broken_monitoring(ns, release, env, log)
    elif helm_status == "deployed" and effective_mode == "k3d":
        # k3d idempotency: CRD re-application on every run stalls for large charts.
        # If all monitoring pods are Running, skip the upgrade.
        pods_res = _kubectl(["-n", ns, "get", "pods", "--no-headers"], env=env, timeout=30)
        pod_lines = [ln for ln in (pods_res.stdout or "").splitlines() if ln.strip()]
        not_running = [
            ln for ln in pod_lines
            if len(ln.split()) >= 3 and ln.split()[2] not in ("Running", "Completed")
        ]
        if pod_lines and not not_running:
            _log(log, f"[MONITORING] Release {release} already deployed and all pods Running — skipping upgrade")
            return

    tmp_values = tempfile.NamedTemporaryFile(
        mode="w", suffix=".yaml", prefix="monitoring-values-", delete=False
    )
    try:
        tmp_values.write(values_yaml)
        tmp_values.flush()
        tmp_values.close()

        recovered_stale_lock = False
        if (
            effective_mode == "k8s"
            and _is_app_cluster_context(env)
            and release == "prometheus"
            and ns == "monitoring"
        ):
            recovered_stale_lock = _recover_stale_prometheus_helm_lock(
                release=release,
                namespace=ns,
                env=env,
                log=log,
            )
            if recovered_stale_lock:
                _log(log, f"[MONITORING] Retrying helm upgrade --install for {release} after stale-lock recovery.")

        _log(log, f"[MONITORING] Deploying {release} in namespace {ns}")
        if effective_mode == "k3d":
            # k3d: the Prometheus operator converges StatefulSets asynchronously
            # after Helm exits; --wait would block on all components (prometheus,
            # alertmanager, node-exporter) and time out. Let Helm apply resources
            # and return immediately; the status check in status_common_services.sh
            # verifies readiness independently.
            _helm(
                [
                    "upgrade", "--install", release, chart,
                    "--namespace", ns,
                    "-f", tmp_values.name,
                    "--timeout", "5m",
                ],
                env=env,
                timeout=360,
                check=True,
            )
        else:
            _helm(
                [
                    "upgrade", "--install", release, chart,
                    "--namespace", ns,
                    "-f", tmp_values.name,
                    "--wait",
                    "--timeout", "10m",
                ],
                env=env,
                timeout=660,
                check=True,
            )

        # Cross-cluster: install Prometheus Operator CRDs on the DB cluster so that
        # CNPG (running on knoe-cnpg-0) can create PodMonitor resources without
        # the reconciler looping on "PodMonitor CRD not present".
        db_ctx = str((env or {}).get("DB_CLUSTER_KUBECONTEXT") or "").strip()
        if db_ctx and effective_mode == "k8s":
            _log(log, f"[MONITORING] Installing Prometheus Operator CRDs on DB cluster ({db_ctx})")
            # helm show crds is client-side — clear KUBECONTEXT so no --kube-context flag
            crd_env = {**(env or {}), "KUBECONTEXT": ""}
            crd_res = _helm(["show", "crds", chart], env=crd_env, timeout=60)
            if crd_res.returncode == 0 and crd_res.stdout.strip():
                db_env = {**(env or {}), "KUBECONTEXT": db_ctx}
                _kubectl(
                    ["apply", "--server-side", "-f", "-"],
                    env=db_env,
                    input_text=crd_res.stdout,
                    timeout=120,
                )
                _log(log, "[MONITORING] Prometheus Operator CRDs installed on DB cluster.")
            else:
                _log(log, "[MONITORING] WARNING: could not fetch CRDs from chart — skipping DB cluster CRD install.")
    finally:
        os.unlink(tmp_values.name)


def restart(
    *,
    namespace: str | None = None,
    env: dict | None = None,
    log: _LogFn | None = None,
) -> None:
    ns = _monitoring_namespace(namespace, env)
    _log(log, f"[MONITORING] Restarting grafana deployment in namespace {ns}")
    _kubectl(["-n", ns, "rollout", "restart", "deployment/prometheus-grafana"], env=env, timeout=180)


def stop(
    *,
    namespace: str | None = None,
    env: dict | None = None,
    log: _LogFn | None = None,
) -> None:
    ns = _monitoring_namespace(namespace, env)
    release = _release_name(env)
    _log(log, f"[MONITORING] Uninstalling release {release} in namespace {ns}")
    _helm(["uninstall", release, "--namespace", ns], env=env, timeout=180)


def status(
    *,
    namespace: str | None = None,
    env: dict | None = None,
) -> bool:
    ns = _monitoring_namespace(namespace, env)
    dep = _kubectl(
        [
            "-n",
            ns,
            "get",
            "deployment",
            "prometheus-grafana",
            "-o",
            "jsonpath={.status.readyReplicas}",
        ],
        env=env,
        timeout=20,
    )
    return _to_bool(dep.returncode == 0 and (dep.stdout or "0").strip() not in {"", "0"})