"""Logs daemon handler.

Reads system logs and journal entries.
"""

import logging
from pathlib import Path

from daemon.server import registry
from lib.common import run_proc

logger = logging.getLogger(__name__)

PROJECT_DIR = Path(__file__).resolve().parent.parent.parent
_APP_LOG_FILE = PROJECT_DIR / "data" / "logs" / "vacuum-wall.log"
_MAX_LINES = 200


def _tail_file(path: str, n: int = _MAX_LINES, sudo: bool = False) -> str:
    """Return the last N lines of a file, optionally via sudo.

    Args:
        path: Absolute path to the file to read.
        n: Number of trailing lines to return.
        sudo: Whether to use sudo to access the file.

    Returns:
        Truncated file content or an error message string.
    """
    try:
        if sudo:
            result = run_proc(["cat", path], sudo=True)
            lines = result.stdout.splitlines(keepends=True)
        else:
            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:
    """Return recent journalctl output for a systemd unit via sudo.

    Args:
        unit: Systemd unit name to query.
        n: Number of journal lines to return.

    Returns:
        Journal output or an error message string.
    """
    try:
        result = run_proc(
            ["journalctl", "--unit=" + unit, "-n", str(n)],
            sudo=True,
            check=False,
            timeout=10,
        )
        output = result.stdout.strip()
        return output if output else f"(no journal entries for {unit})\n"
    except Exception as exc:
        return f"(error reading journal: {exc})\n"


@registry.register("GET", "/logs/journal")
def journal(_request, _body) -> str:
    """GET /logs/journal — return vacuum-wall daemon journal entries."""
    return _sudo_journalctl("vacuum-wall")


@registry.register("GET", "/logs/nginx/access")
def nginx_access(_request, _body) -> str:
    """GET /logs/nginx/access — return recent nginx access log lines."""
    return _tail_file("/var/log/nginx/access.log", sudo=True)


@registry.register("GET", "/logs/nginx/error")
def nginx_error(_request, _body) -> str:
    """GET /logs/nginx/error — return recent nginx error log lines."""
    return _tail_file("/var/log/nginx/error.log", sudo=True)


@registry.register("GET", "/logs/dnsmasq")
def dnsmasq_log(_request, _body) -> str:
    """GET /logs/dnsmasq — return recent dnsmasq journal entries."""
    return _sudo_journalctl("dnsmasq")


@registry.register("GET", "/logs/app")
def app_log(_request, _body) -> str:
    """GET /logs/app — return recent application log lines."""
    return _tail_file(str(_APP_LOG_FILE))