package main

import (
    "github.com/aws/aws-lambda-go/lambda"
    "github.com/aquasecurity/lmdrouter"
)

var router *lmdrouter.Router

func init() {
    router = lmdrouter.NewRouter("/api", loggerMiddleware, authMiddleware)
    router.Route("GET", "/", listSomethings)
    router.Route("POST", "/", postSomething, someOtherMiddleware)
    router.Route("GET", "/:id", getSomething)
    router.Route("PUT", "/:id", updateSomething)
    router.Route("DELETE", "/:id", deleteSomething)
}

func main() {
    lambda.Start(router.Handler)
}

// the rest of the code is a redacted example, it will probably reside in a
// separate package inside your project

type listSomethingsInput struct {
    ID                string   `lambda:"path.id"`                // a path parameter declared as :id
    ShowSomething     bool     `lambda:"query.show_something"`   // a query parameter named "show_something"
    AcceptedLanguages []string `lambda:"header.Accept-Language"` // a multi-value header parameter
}

type postSomethingInput struct {
    Title   string    `json:"title"`
    Date    time.Time `json:"date"`
}

func listSomethings(ctx context.Context, req events.APIGatewayProxyRequest) (
    res events.APIGatewayProxyResponse,
    err error,
) {
    // parse input from request and path parameters
    var input listSomethingsInput
    err = lmdrouter.UnmarshalRequest(req, false, &input)
    if err != nil {
        return lmdrouter.HandleError(err)
    }

    // call some business logic that generates an output struct
    // ...

    return lmdrouter.MarshalResponse(http.StatusOK, nil, output)
}

func postSomethings(ctx context.Context, req events.APIGatewayProxyRequest) (
    res events.APIGatewayProxyResponse,
    err error,
) {
    // parse input from request body
    var input postSomethingsInput
    err = lmdrouter.UnmarshalRequest(req, true, &input)
    if err != nil {
        return lmdrouter.HandleError(err)
    }

    // call some business logic that generates an output struct
    // ...

    return lmdrouter.MarshalResponse(http.StatusCreated, nil, output)
}

func loggerMiddleware(next lmdrouter.Handler) lmdrouter.Handler {
    return func(ctx context.Context, req events.APIGatewayProxyRequest) (
        res events.APIGatewayProxyResponse,
        err error,
    ) {
        // [LEVEL] [METHOD PATH] [CODE] EXTRA
        format := "[%s] [%s %s] [%d] %s"
    	level := "INF"
    	var code int
    	var extra string

    	res, err = next(ctx, req)
    	if err != nil {
    	    level = "ERR"
    	    code = http.StatusInternalServerError
    	    extra = " " + err.Error()
    	} else {
    	    code = res.StatusCode
    	    if code >= 400 {
    	        level = "ERR"
    	    }
        }

        log.Printf(format, level, req.HTTPMethod, req.Path, code, extra)

        return res, err
    }
}