package econetmcp

import (
	"context"
	"fmt"
	"strings"

	"github.com/modelcontextprotocol/go-sdk/mcp"
	"k8s.io/utils/ptr"

	pb "gitea.libretechconsulting.com/rmcguire/econet-exporter/api/econet/v1alpha1"
)

var ListDevicesTool = &mcp.Tool{
	Name:        "list_water_heaters",
	Title:       "List EcoNet Water Heaters",
	Description: "Lists Rheem EcoNet devices and their current state (mode, setpoint, " +
		"hot water availability, connectivity). Optionally filter to one serial number.",
	Annotations: &mcp.ToolAnnotations{
		ReadOnlyHint:  true,
		OpenWorldHint: ptr.To(true),
	},
}

type ListDevicesParams struct {
	SerialNumber string `json:"serial_number,omitempty" jsonschema:"Optional device serial number to return a single device"`
}

func (m *EconetMCPServer) addListDevicesTool() {
	mcp.AddTool(m.server, ListDevicesTool, m.listDevicesHandler)
}

func (m *EconetMCPServer) listDevicesHandler(ctx context.Context, _ *mcp.CallToolRequest, args *ListDevicesParams) (
	*mcp.CallToolResult, any, error,
) {
	m.log.Debug().Str("serial", args.SerialNumber).Msg("list water heaters tool called")

	devices, err := m.lookup(ctx, args.SerialNumber)
	if err != nil {
		return &mcp.CallToolResult{IsError: true, Meta: mcp.Meta{"error": err.Error()}}, nil, err
	}

	return &mcp.CallToolResult{
		Content: []mcp.Content{&mcp.TextContent{Text: summarizeDevices(devices)}},
	}, nil, nil
}

func (m *EconetMCPServer) lookup(ctx context.Context, serial string) ([]*pb.Device, error) {
	if serial != "" {
		resp, err := m.econetGRPC.GetDevice(ctx, &pb.GetDeviceRequest{SerialNumber: serial})
		if err != nil {
			return nil, err
		}
		return []*pb.Device{resp.GetDevice()}, nil
	}

	resp, err := m.econetGRPC.ListDevices(ctx, &pb.ListDevicesRequest{})
	if err != nil {
		return nil, err
	}
	return resp.GetDevices(), nil
}

func summarizeDevices(devices []*pb.Device) string {
	if len(devices) == 0 {
		return "No EcoNet devices found."
	}
	var b strings.Builder
	for _, d := range devices {
		fmt.Fprintf(&b, "%s (%s, serial %s): mode=%s setpoint=%d°F running=%t connected=%t hotWater=%d%% alerts=%d\n",
			d.GetFriendlyName(), d.GetGenericType(), d.GetSerialNumber(),
			d.GetMode(), d.GetSetpoint(), d.GetRunning(), d.GetConnected(),
			d.GetHotWaterAvailability(), d.GetAlertCount())
	}
	return strings.TrimRight(b.String(), "\n")
}