// Package service defines generics around implementation of
// a new service that provides configuration for go-app
//
// The interface is meant to make the template more clear to implement
// without unnecessary changes in main.go
package service

import (
	"context"

	"gitea.libretechconsulting.com/rmcguire/go-server-with-otel/pkg/config"

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

type ShutdownFunc func(ctx context.Context) (string, error)

type AppService interface {
	Init(ctx context.Context, config *config.ServiceConfig) (ShutdownFunc, error)
	GetGRPC() *optsgrpc.AppGRPC
	GetHTTP() *optshttp.AppHTTP
}

// MergeServices is used if multiple services are served by this server
// with their own distinct packages and configuration
//
// You should be overriding the done chan, listener, or any other
// configuration used by the SERVER rather than the individual services.
func MergeServices(ctx context.Context, appServices ...AppService) (*optsgrpc.AppGRPC, *optshttp.AppHTTP) {
	mergedGRPC := &optsgrpc.AppGRPC{}
	for _, svc := range appServices {
		mergedGRPC = mergeGRPC(mergedGRPC, svc.GetGRPC())
	}

	mergedHTTP := &optshttp.AppHTTP{}
	for _, svc := range appServices {
		mergedHTTP = mergeHTTP(mergedHTTP, svc.GetHTTP())
	}
	mergedHTTP.Ctx = ctx

	return mergedGRPC, mergedHTTP
}

func mergeHTTP(a *optshttp.AppHTTP, b *optshttp.AppHTTP) *optshttp.AppHTTP {
	return &optshttp.AppHTTP{
		Funcs:        append(a.Funcs, b.Funcs...),
		Middleware:   append(a.Middleware, b.Middleware...),
		Handlers:     append(a.Handlers, b.Handlers...),
		HealthChecks: append(a.HealthChecks, b.HealthChecks...),
	}
}

func mergeGRPC(a *optsgrpc.AppGRPC, b *optsgrpc.AppGRPC) *optsgrpc.AppGRPC {
	return &optsgrpc.AppGRPC{
		Services:           append(a.Services, b.Services...),
		GRPCOpts:           append(a.GRPCOpts, b.GRPCOpts...),
		UnaryInterceptors:  append(a.UnaryInterceptors, b.UnaryInterceptors...),
		StreamInterceptors: append(a.StreamInterceptors, b.StreamInterceptors...),
		GRPCDialOpts:       append(a.GRPCDialOpts, b.GRPCDialOpts...),
		GRPCGatewayOpts:    append(a.GRPCGatewayOpts, b.GRPCGatewayOpts...),
	}
}