"""Unified monitors management surface (/monitors) — ping, DNS, HTTP.

Replaces the former /ping, /dns and /plugins/http pages. One list, one
type-aware add/edit form, one dashboard widget. A monitor may be linked to a
Host (host_id) or watch a free-standing custom destination (host_id = NULL).
"""
from __future__ import annotations
import json
import uuid
from datetime import datetime, timezone

from quart import Blueprint, current_app, render_template, request, redirect, url_for
from sqlalchemy import select

from steward.auth.middleware import require_role
from steward.models.users import UserRole
from steward.models.monitors import Monitor, MonitorType, MONITOR_TYPE_VALUES
from steward.core.status import _last_n_results, _uptime_by_monitor, _heartbeat_title
from steward.core.time_range import parse_range, DEFAULT_RANGE

monitors_bp = Blueprint("monitors", __name__, url_prefix="/monitors")


def _build_config(form, mtype: str) -> dict:
    """Assemble the type-specific config dict from submitted form fields."""
    if mtype == MonitorType.tcp.value:
        return {"port": int(form.get("port") or 80)}
    if mtype == MonitorType.dns.value:
        return {"expected_ip": (form.get("expected_ip", "").strip() or None)}
    if mtype == MonitorType.http.value:
        try:
            headers = json.loads(form.get("headers_json") or "{}")
        except (ValueError, TypeError):
            headers = {}
        return {
            "method": form.get("method", "GET").upper(),
            "expected_status": int(form.get("expected_status", 200) or 200),
            "content_match": form.get("content_match", "").strip(),
            "headers": headers,
            "timeout_seconds": int(form.get("timeout_seconds", 10) or 10),
            "follow_redirects": "follow_redirects" in form,
            "verify_ssl": "verify_ssl" in form,
        }
    return {}  # icmp


def _normalise_target(mtype: str, target: str) -> str:
    """For http, default a bare host to https://; others pass through."""
    target = target.strip()
    if mtype == MonitorType.http.value and target and not target.startswith(("http://", "https://")):
        return "https://" + target
    return target


async def _rows_data(range_key: str):
    """Per-monitor display data for the list / widget."""
    since, range_key = parse_range(range_key)
    async with current_app.db_sessionmaker() as db:
        monitors = list((await db.execute(
            select(Monitor).order_by(Monitor.name)
        )).scalars())
        ids = [m.id for m in monitors]
        recent = await _last_n_results(db, ids)
        uptime = await _uptime_by_monitor(db, ids)

    # Map the selected range to the uptime bucket we surface in the list.
    bucket = {"24h": "24h", "7d": "7d", "30d": "30d"}.get(range_key, "24h")
    now = datetime.now(timezone.utc)
    data = []
    for m in monitors:
        rows = recent.get(m.id, [])
        latest = rows[-1] if rows else None
        tls_days = None
        if latest and latest.tls_expires_at:
            tls_days = (latest.tls_expires_at - now).total_seconds() / 86400.0
        data.append({
            "monitor": m,
            "latest": latest,
            "heartbeat": [{"state": "up" if r.is_up else "down",
                           "title": _heartbeat_title(m.type, r)} for r in rows],
            "uptime_pct": uptime.get(m.id, {}).get(bucket),
            "tls_days": tls_days,
        })
    up = sum(1 for d in data if d["latest"] and d["latest"].is_up)
    down = sum(1 for d in data if d["latest"] and not d["latest"].is_up)
    pending = sum(1 for d in data if not d["latest"])
    return data, up, down, pending, range_key


@monitors_bp.get("/")
@require_role(UserRole.viewer)
async def index():
    poll_interval = current_app.config.get("MONITORS_POLL_INTERVAL", 60)
    return await render_template(
        "monitors/index.html",
        poll_interval=poll_interval,
        current_range=request.args.get("range", DEFAULT_RANGE),
        types=list(MonitorType),
    )


@monitors_bp.get("/rows")
@require_role(UserRole.viewer)
async def rows():
    data, up, down, pending, range_key = await _rows_data(
        request.args.get("range", DEFAULT_RANGE)
    )
    return await render_template(
        "monitors/rows.html",
        monitor_data=data, up=up, down=down, pending=pending, range_key=range_key,
    )


@monitors_bp.post("/add")
@require_role(UserRole.operator)
async def add_monitor():
    form = await request.form
    mtype = form.get("type", "").strip()
    target = _normalise_target(mtype, form.get("target", ""))
    if mtype not in MONITOR_TYPE_VALUES or not target:
        return redirect(url_for("monitors.index"))

    host_id = form.get("host_id", "").strip() or None
    monitor = Monitor(
        id=str(uuid.uuid4()),
        name=form.get("name", "").strip() or target,
        type=mtype,
        target=target,
        host_id=host_id,
        config_json=json.dumps(_build_config(form, mtype)),
        enabled=True,
        check_interval_seconds=int(form.get("check_interval_seconds", 0) or 0),
        created_at=datetime.now(timezone.utc),
    )
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            db.add(monitor)

    # A host-scoped add returns to that host's hub; otherwise the monitors page.
    if host_id:
        return redirect(url_for("hosts.host_detail", host_id=host_id))
    return redirect(url_for("monitors.index"))


@monitors_bp.get("/<monitor_id>/edit")
@require_role(UserRole.operator)
async def edit_form(monitor_id: str):
    async with current_app.db_sessionmaker() as db:
        m = await db.get(Monitor, monitor_id)
    if not m:
        return redirect(url_for("monitors.index"))
    return await render_template(
        "monitors/edit.html", monitor=m, config=m.config, types=list(MonitorType),
    )


@monitors_bp.post("/<monitor_id>/edit")
@require_role(UserRole.operator)
async def edit_monitor(monitor_id: str):
    form = await request.form
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            m = await db.get(Monitor, monitor_id)
            if not m:
                return redirect(url_for("monitors.index"))
            # Type is immutable on edit (changes the meaning of config/target);
            # to switch type, delete and re-add.
            m.name = form.get("name", "").strip() or m.target
            m.target = _normalise_target(m.type, form.get("target", m.target))
            m.config_json = json.dumps(_build_config(form, m.type))
            m.check_interval_seconds = int(form.get("check_interval_seconds", 0) or 0)
    return redirect(url_for("monitors.index"))


@monitors_bp.post("/<monitor_id>/toggle")
@require_role(UserRole.operator)
async def toggle_monitor(monitor_id: str):
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            m = await db.get(Monitor, monitor_id)
            if m:
                m.enabled = not m.enabled
    return redirect(request.referrer or url_for("monitors.index"))


@monitors_bp.post("/<monitor_id>/delete")
@require_role(UserRole.operator)
async def delete_monitor(monitor_id: str):
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            m = await db.get(Monitor, monitor_id)
            if m:
                await db.delete(m)
    return redirect(request.referrer or url_for("monitors.index"))


@monitors_bp.get("/widget")
@require_role(UserRole.viewer)
async def widget():
    type_filter = request.args.get("type_filter", "all")
    show_down_only = request.args.get("show_down_only", "no") == "yes"
    limit = max(1, min(50, int(request.args.get("limit", 10) or 10)))
    widget_id = request.args.get("wid", "0")

    data, up, down, pending, _ = await _rows_data(DEFAULT_RANGE)
    if type_filter in MONITOR_TYPE_VALUES:
        data = [d for d in data if d["monitor"].type == type_filter]
    if show_down_only:
        data = [d for d in data if not (d["latest"] and d["latest"].is_up)]

    return await render_template(
        "monitors/widget.html",
        monitor_data=data[:limit], up=up, down=down, pending=pending,
        show_down_only=show_down_only, widget_id=widget_id,
    )