# plugins/syslog/routes.py
"""The Syslog page: whether the listener is open, the sources whose lines are
kept, and the senders offered to be added. Every GET reads Steward's own rows
and the listener's state in memory; nothing here contacts a device (System
178's ruling). Adding, ignoring, editing and removing a source are an admin's,
and audited."""
from __future__ import annotations

from datetime import datetime, timezone

from quart import Blueprint, abort, current_app, redirect, render_template, request, session
from sqlalchemy import select

from steward.auth.middleware import require_role
from steward.core.audit import log_audit
from steward.models.users import UserRole

from .models import SyslogSource
from .parse import severity_name
from .receiver import LISTENER, MAX_SENDERS, settings

syslog_bp = Blueprint("syslog", __name__, template_folder="templates")

INDEX = "/plugins/syslog/"


def _actor() -> tuple[str | None, str]:
    return session.get("user_id"), session.get("username", "")


async def _hosts(db) -> list:
    from steward.models.hosts import Host
    return list((await db.execute(select(Host.id, Host.name, Host.address).order_by(Host.name))).all())


def listener_view(port: int, udp: bool, tcp: bool) -> dict:
    """What the page says about the listener: open on which protocols, or
    why not."""
    protocols = [p for p, on in (("UDP", udp), ("TCP", tcp)) if on]
    return {"port": port, "protocols": protocols, "listening": LISTENER.listening,
            "error": LISTENER.error, "bound_at": LISTENER.bound_at,
            "received": LISTENER.received, "dropped": LISTENER.dropped,
            "unoffered": LISTENER.unoffered, "connections": LISTENER.connections,
            "senders_full": False, "max_senders": MAX_SENDERS}


def source_view(s: SyslogSource, hosts: dict) -> dict:
    host = hosts.get(s.host_id) if s.host_id else None
    return {"id": s.id, "address": s.address, "state": s.state,
            "name": s.name or s.hostname_seen or s.address,
            "hostname_seen": s.hostname_seen, "host": host,
            "first_seen_at": s.first_seen_at, "last_seen_at": s.last_seen_at,
            "lines_total": s.lines_total or 0,
            "severity": severity_name(s.last_severity) if s.last_severity is not None else None,
            "level": s.last_severity, "last_line": s.last_line}


def suggested_host(source: SyslogSource, hosts: list) -> str | None:
    """The host whose address is the sender's, if one is."""
    return next((h.id for h in hosts if h.address == source.address), None)


@syslog_bp.get("/")
@require_role(UserRole.viewer)
async def index():
    async with current_app.db_sessionmaker() as db:
        rows = list((await db.execute(
            select(SyslogSource).order_by(SyslogSource.last_seen_at.desc()))).scalars())
        hosts = await _hosts(db)
    by_id = {h.id: h for h in hosts}
    views = {state: [] for state in ("accepted", "offered", "ignored")}
    for row in rows:
        v = source_view(row, by_id)
        if row.state == "offered":
            v["suggested_host"] = suggested_host(row, hosts)
        views.setdefault(row.state, []).append(v)
    views["accepted"].sort(key=lambda v: v["name"].lower())
    listener = listener_view(*settings(current_app))
    listener["senders_full"] = len(rows) >= MAX_SENDERS
    return await render_template("syslog/index.html", listener=listener,
                                 sources=views["accepted"], offered=views["offered"],
                                 ignored=views["ignored"], hosts=hosts,
                                 now=datetime.now(timezone.utc))


async def _source_or_404(db, source_id: str) -> SyslogSource:
    source = await db.get(SyslogSource, source_id)
    if source is None:
        abort(404)
    return source


async def _host_id(db, value: str | None) -> str | None:
    from steward.models.hosts import Host
    if not value:
        return None
    return value if await db.get(Host, value) is not None else None


@syslog_bp.post("/sources/<source_id>/add")
@require_role(UserRole.admin)
async def add_source(source_id: str):
    """Keep an offered sender's lines from now on, under the name given."""
    form = await request.form
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            source = await _source_or_404(db, source_id)
            source.name = (form.get("name") or "").strip()[:100] or source.hostname_seen or source.address
            source.host_id = await _host_id(db, form.get("host_id"))
            source.state = "accepted"
            detail = {"name": source.name, "address": source.address}
    await log_audit(current_app, *_actor(), "syslog.source_added", entity_type="syslog_source",
                    entity_id=source_id, detail=detail)
    return redirect(INDEX)


@syslog_bp.post("/sources/<source_id>/ignore")
@require_role(UserRole.admin)
async def ignore_source(source_id: str):
    """Stop offering a sender: it is still counted, never kept."""
    return await _set_state(source_id, "ignored", "syslog.source_ignored")


@syslog_bp.post("/sources/<source_id>/offer")
@require_role(UserRole.admin)
async def offer_source(source_id: str):
    """Offer an ignored sender again."""
    return await _set_state(source_id, "offered", "syslog.source_offered")


async def _set_state(source_id: str, state: str, action: str):
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            source = await _source_or_404(db, source_id)
            source.state = state
            detail = {"address": source.address}
    await log_audit(current_app, *_actor(), action, entity_type="syslog_source",
                    entity_id=source_id, detail=detail)
    return redirect(INDEX)


@syslog_bp.get("/sources/<source_id>/edit")
@require_role(UserRole.admin)
async def edit_source(source_id: str):
    async with current_app.db_sessionmaker() as db:
        source = await _source_or_404(db, source_id)
        hosts = await _hosts(db)
    return await render_template("syslog/edit.html", source=source, hosts=hosts,
                                 label=source.name or source.hostname_seen or source.address)


@syslog_bp.post("/sources/<source_id>/edit")
@require_role(UserRole.admin)
async def save_source(source_id: str):
    form = await request.form
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            source = await _source_or_404(db, source_id)
            old_name = source.name
            source.name = (form.get("name") or "").strip()[:100] or source.hostname_seen or source.address
            source.host_id = await _host_id(db, form.get("host_id"))
            detail = {"name": source.name}
            if old_name != source.name:
                detail["old_name"] = old_name
    await log_audit(current_app, *_actor(), "syslog.source_updated", entity_type="syslog_source",
                    entity_id=source_id, detail=detail)
    return redirect(INDEX)


@syslog_bp.post("/sources/<source_id>/delete")
@require_role(UserRole.admin)
async def delete_source(source_id: str):
    """Remove a source and the lines kept from it. A device still sending is
    offered again."""
    async with current_app.db_sessionmaker() as db:
        async with db.begin():
            source = await _source_or_404(db, source_id)
            detail = {"name": source.name, "address": source.address}
            await db.delete(source)
    await log_audit(current_app, *_actor(), "syslog.source_removed", entity_type="syslog_source",
                    entity_id=source_id, detail=detail)
    return redirect(INDEX)