package main

import (
	"bytes"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strings"
)

func main() {
	// Name of the executable
	exeName := "poster"
	// Help Message (-h, --help)
	helpMsg := `Usage: %[1]s [FLAGS] URL
Execute HTTP-Requests and print responses to stdout

  -m <method> Method to use for the request (default "get")
     POST '{"mydata": "string", "nene": 31}' https://rest.api/lele/lala
     PUT '{"mydata": "string", "nene": 31}' https://rest.api/lele/lala/31
     PATCH '{"mydata": "string", "nene": 31}' https://rest.api/lele/lala/31
     Note: Use "" around everything but numbers, also wrap whole json in ''
  -h, --help Print this message.

Examples:
  %[1]s https://rest.api/posts/1337
  %[1]s -m PUT '{"fooo": "bäü߀r", "userId": 42}' https://rest.api/posts/1
  %[1]s -m DELETE https://rest.api/posts/1
`
	flag.Usage = func() {
		fmt.Fprintf(flag.CommandLine.Output(), helpMsg, exeName)
	}

	// Name, default val, help
	m := flag.String("m", "get", "Method for the request.")

	flag.Parse()
	// Number of all flags (executable name included -> 0 indexed)
	l := len(os.Args) - flag.NArg()
	// Only get the arguments after all flags
	args := os.Args[l:]
	al := len(args)
	// Requested url/web resource
	resource := args[al - 1]
	// http client used for PUT, PATCH, DELETE
	client := &http.Client{}

	method := strings.ToLower(*m)
	switch method {
	// -------------------------------------------------------------------------
	//	GET
	// -------------------------------------------------------------------------
	case "get":
		fmt.Println("GET -> " + resource + " reported:")
		res, err := http.Get(resource)
		if err != nil {
			log.Fatal(err)
		}
		defer res.Body.Close()
		// Read everything from body
		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			log.Fatal(err)
		}
		fmt.Printf("\n\n%s\n\n", body)
	// -------------------------------------------------------------------------
	//	HEAD
	// -------------------------------------------------------------------------
	case "head":
		fmt.Println("HEAD -> " + resource + " reported:")
		res, err := http.Head(resource)
		if err != nil {
			log.Fatal(err)
		}
		fmt.Printf("\n\n%s\n\n", res.Header)
	// -------------------------------------------------------------------------
	//	POST
	// -------------------------------------------------------------------------
	case "post":
		fmt.Println("POST -> " + resource + " reported:")
		if al != 2 {
			msg := `Error: Wrong number of arguments
Usage: %s -m POST '{"mydata": "string", "nene": 31}' https://a-website.org/lele/lala
Note: Use "" around everything but numbers, also wrap json in ''
`
			fmt.Printf(msg, exeName)
			os.Exit(1)
		}
		data := args[0]
		res, err := http.Post(resource, "application/json; charset=UTF-8", bytes.NewBufferString(data))
		if err != nil {
			log.Fatal(err)
		}
		defer res.Body.Close()
		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			log.Fatal(err)
		}
		fmt.Printf("\n\n%s\n\n", body)
	// -------------------------------------------------------------------------
	//	PUT
	// -------------------------------------------------------------------------
	case "put":
		fmt.Println("PUT -> " + resource + " reported:")
		if al != 2 {
			msg := `Error: Wrong number of arguments
Usage: %s -m PUT '{"mydata": "string", "nene": 31}' https://a-website.org/lele/lala/123
Note: Use "" around everything but numbers, also wrap json in ''
`
			fmt.Printf(msg, exeName)
			os.Exit(1)
		}
		data := args[0]
		req, err := http.NewRequest(http.MethodPut, resource ,bytes.NewBufferString(data))
		if err != nil {
			log.Fatal(err)
		}
		req.Header.Set("Content-Type", "application/json; charset=UTF-8")
		res, err := client.Do(req)
		defer res.Body.Close()
		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			log.Fatal(err)
		}
		fmt.Printf("\n\n%s\n\n", body)
	// -------------------------------------------------------------------------
	//	PATCH
	// -------------------------------------------------------------------------
	case "patch":
		fmt.Println("PATCH -> " + resource + " reported:")
		if al != 2 {
			msg := `Error: Wrong number of arguments
Usage: %s -m PUT '{"mydata": "string", "nene": 31}' https://a-website.org/lele/lala/123
Note: Use "" around everything but numbers, also wrap json in ''
`
			fmt.Printf(msg, exeName)
			os.Exit(1)
		}
		data := args[0]
		req, err := http.NewRequest(http.MethodPatch, resource ,bytes.NewBufferString(data))
		if err != nil {
			log.Fatal(err)
		}
		req.Header.Set("Content-Type", "application/json; charset=UTF-8")
		res, err := client.Do(req)
		defer res.Body.Close()
		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			log.Fatal(err)
		}
		fmt.Printf("\n\n%s\n\n", body)
	// -------------------------------------------------------------------------
	//	DELETE
	// -------------------------------------------------------------------------
	case "delete":
		fmt.Println("DELETE -> " + resource + " reported:")
		req, err := http.NewRequest(http.MethodDelete, resource, nil)
		if err != nil {
			log.Fatal(err)
		}
		res, err := client.Do(req)
		defer res.Body.Close()
		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			log.Fatal(err)
		}
		fmt.Printf("\n\n%s\n\n", body)
	// -------------------------------------------------------------------------
	//	DEFAULT
	// -------------------------------------------------------------------------
	default:
		fmt.Println("Method unknown, use: GET, HEAD, POST, PUT, PATCH, DELETE")
	}
}