"""
webui/api/logs.py - Log viewing API blueprint.

Serves log content to the /logs page via HTMX endpoints:
  /api/logs/journal       — systemd journal for vacuum-wall
  /api/logs/nginx/access  — nginx access log tail
  /api/logs/nginx/error   — nginx error log tail
  /api/logs/dnsmasq       — systemd journal for dnsmasq
  /api/logs/app           — Vacuum Wall application log file
"""

import logging
import subprocess
from pathlib import Path

from flask import Blueprint, render_template_string

logger = logging.getLogger(__name__)

bp = Blueprint("logs", __name__)

PROJECT_DIR = Path(__file__).resolve().parent.parent
APP_LOG_FILE = PROJECT_DIR / "data" / "logs" / "vacuum-wall.log"

_MAX_LINES = 200


def _tail_file(path: str, n: int = _MAX_LINES) -> str:
    """Return the last *n* lines of a file."""
    try:
        with open(path) as f:
            lines = f.readlines()
        return "".join(lines[-n:])
    except FileNotFoundError:
        return "(log file not found)\n"
    except PermissionError:
        return "(permission denied)\n"


def _sudo_journalctl(unit: str, n: int = _MAX_LINES) -> str:
    """Run ``sudo journalctl -u <unit> --no-pager -n <n>`` and return output."""
    try:
        result = subprocess.run(
            ["sudo", "journalctl", "-u", unit, "--no-pager", "-n", str(n)],
            capture_output=True,
            text=True,
            timeout=10,
        )
        output = result.stdout.strip()
        return output if output else f"(no journal entries for {unit})\n"
    except (subprocess.TimeoutExpired, FileNotFoundError) as exc:
        return f"(error reading journal: {exc})\n"


_LOG_LINE_TEMPLATE = """\
{% for line in lines %}
<div class="log-line{% if 'ERROR' in line %} log-error{% elif 'WARN' in line %} log-warn{% endif %}">{{ line | e }}</div>
{% endfor %}"""


def _render_log_lines(text: str) -> str:
    """Render raw log text into HTML fragment with line-by-line coloring."""
    lines = text.rstrip("\n").split("\n") if text.strip() else []
    return render_template_string(_LOG_LINE_TEMPLATE, lines=lines)


# ---------------------------------------------------------------------------
# Endpoints
# ---------------------------------------------------------------------------


@bp.route("/journal")
def journal():
    text = _sudo_journalctl("vacuum-wall")
    return _render_log_lines(text)


@bp.route("/nginx/access")
def nginx_access():
    text = _tail_file("/var/log/nginx/access.log")
    return _render_log_lines(text)


@bp.route("/nginx/error")
def nginx_error():
    text = _tail_file("/var/log/nginx/error.log")
    return _render_log_lines(text)


@bp.route("/dnsmasq")
def dnsmasq():
    text = _sudo_journalctl("dnsmasq")
    return _render_log_lines(text)


@bp.route("/app")
def app_log():
    text = _tail_file(str(APP_LOG_FILE))
    return _render_log_lines(text)