"""Monitoring tools for HAProxy MCP Server."""

from typing import Annotated

from pydantic import Field

from ..exceptions import HaproxyError
from ..validation import validate_backend_name
from ..haproxy_client import haproxy_cmd
from ..utils import parse_stat_csv


def register_monitoring_tools(mcp):
    """Register monitoring tools with MCP server."""

    @mcp.tool()
    def haproxy_stats() -> str:
        """Get HAProxy status and statistics.

        Returns:
            Key HAProxy metrics (name, version, uptime, connections, etc.)
        """
        try:
            result = haproxy_cmd("show info")
            stats = {}
            for line in result.split("\n"):
                if ":" in line:
                    key, value = line.split(":", 1)
                    stats[key.strip()] = value.strip()

            important = ["Name", "Version", "Uptime_sec", "CurrConns", "MaxConn", "Run_queue", "Tasks"]
            output = []
            for key in important:
                if key in stats:
                    output.append(f"• {key}: {stats[key]}")

            return "\n".join(output) if output else result
        except HaproxyError as e:
            return f"Error: {e}"

    @mcp.tool()
    def haproxy_backends() -> str:
        """List all HAProxy backends.

        Returns:
            List of all configured backend names
        """
        try:
            result = haproxy_cmd("show backend")
            backends = [line for line in result.split("\n") if line and not line.startswith("#")]
            return "Backends:\n" + "\n".join(f"• {b}" for b in backends)
        except HaproxyError as e:
            return f"Error: {e}"

    @mcp.tool()
    def haproxy_list_frontends() -> str:
        """List all HAProxy frontends with their status.

        Returns:
            List of frontends with status and session counts
        """
        try:
            result = haproxy_cmd("show stat")
            frontends = []
            for stat in parse_stat_csv(result):
                if stat["svname"] == "FRONTEND":
                    frontends.append(
                        f"• {stat['pxname']}: {stat['status']} (sessions: {stat['scur']})"
                    )
            if not frontends:
                return "No frontends found"
            return "Frontends:\n" + "\n".join(frontends)
        except HaproxyError as e:
            return f"Error: {e}"

    @mcp.tool()
    def haproxy_get_connections(
        backend: Annotated[str, Field(default="", description="Optional: Backend name to filter (e.g., 'pool_1'). Empty = all backends")] = ""
    ) -> str:
        """Get active connection counts per server for monitoring traffic distribution."""
        if backend and not validate_backend_name(backend):
            return "Error: Invalid backend name (use alphanumeric, underscore, hyphen only)"
        try:
            result = haproxy_cmd("show stat")
            connections = []
            for stat in parse_stat_csv(result):
                if backend and stat["pxname"] != backend:
                    continue
                if stat["svname"] in ["FRONTEND", "BACKEND"]:
                    connections.append(
                        f"• {stat['pxname']} ({stat['svname']}): {stat['scur']} current, {stat['smax']} max"
                    )
                elif stat["svname"]:
                    connections.append(f"  - {stat['svname']}: {stat['scur']} connections")
            return "\n".join(connections) if connections else "No connection data"
        except HaproxyError as e:
            return f"Error: {e}"