// Package econet provides EconetService, a service.AppService that connects
// to the Rheem EcoNet cloud and exposes device state via gRPC, an MCP tool,
// and OTEL metrics served for Prometheus scraping.
package econet

import (
	"context"
	"crypto/tls"
	"fmt"
	"log/slog"
	"net/http"

	rheemcloud "github.com/kevinburke/rheemcloud-go"

	optsgrpc "gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/grpc/opts"
	optshttp "gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/http/opts"

	"gitea.libretechconsulting.com/rmcguire/econet-exporter/pkg/config"
	"gitea.libretechconsulting.com/rmcguire/econet-exporter/pkg/econet/econetgrpc"
	"gitea.libretechconsulting.com/rmcguire/econet-exporter/pkg/econet/econetmcp"
	"gitea.libretechconsulting.com/rmcguire/econet-exporter/pkg/econet/econetmetrics"
	"gitea.libretechconsulting.com/rmcguire/econet-exporter/pkg/service"
)

type EconetService struct {
	ctx     context.Context
	config  *config.ServiceConfig
	client  *rheemcloud.Client
	grpc    *econetgrpc.EconetGRPCServer
	mcp     *econetmcp.EconetMCPServer
	metrics *econetmetrics.Collector
}

func (e *EconetService) Init(ctx context.Context, cfg *config.ServiceConfig) (service.ShutdownFunc, error) {
	e.ctx = ctx
	e.config = cfg

	client, err := connect(ctx, cfg)
	if err != nil {
		return nil, err
	}
	e.client = client

	e.grpc = econetgrpc.NewEconetGRPCServer(ctx, cfg, client)
	e.mcp = econetmcp.NewEconetMCPServer(ctx, cfg, e.grpc)
	e.metrics = econetmetrics.NewCollector(ctx, cfg, client)
	if err := e.metrics.Start(); err != nil {
		return nil, err
	}

	return e.shutdown, nil
}

func connect(ctx context.Context, cfg *config.ServiceConfig) (*rheemcloud.Client, error) {
	if cfg.EconetEmail == "" || cfg.EconetPassword == "" {
		return nil, fmt.Errorf("econet: email and password required (set ECONET_EMAIL / ECONET_PASSWORD)")
	}
	client, err := rheemcloud.Connect(ctx, cfg.EconetEmail, cfg.EconetPassword, &rheemcloud.Config{
		Logger: slog.Default(),
		HTTPClient: &http.Client{
			Transport: &http.Transport{
				TLSClientConfig: &tls.Config{
					InsecureSkipVerify: cfg.EconetTLSInsecure,
				},
			},
		},
	})
	if err != nil {
		return nil, fmt.Errorf("econet: connect failed: %w", err)
	}
	return client, nil
}

func (e *EconetService) shutdown(_ context.Context) (string, error) {
	e.metrics.Stop()
	return "EconetService", e.client.Close()
}

func (e *EconetService) GetGRPC() *optsgrpc.AppGRPC {
	return &optsgrpc.AppGRPC{
		Services:     e.grpc.GetServices(),
		GRPCDialOpts: e.grpc.GetDialOpts(),
	}
}

func (e *EconetService) GetHTTP() *optshttp.AppHTTP {
	return &optshttp.AppHTTP{
		Ctx:          e.ctx,
		Handlers:     e.mcp.GetHandlers(),
		HealthChecks: e.healthChecks(),
	}
}

func (e *EconetService) healthChecks() []optshttp.HealthCheckFunc {
	return []optshttp.HealthCheckFunc{
		func(_ context.Context) error {
			if len(e.client.Devices()) == 0 {
				return fmt.Errorf("econet: no devices loaded")
			}
			return nil
		},
	}
}