package gfw

import (
	"encoding/json"
	"log"
	"math"
	"net/http"
	"strings"
)

func buildRequest(req *http.Request) (*Request, error) {

	/* (1) Init request */
	uri := NormaliseUri(req.URL.Path)
	inst := &Request{
		Uri:      strings.Split(uri, "/"),
		GetData:  FetchGetData(req),
		FormData: FetchFormData(req),
	}

	return inst, nil
}

// NormaliseUri removes the trailing '/' to always
// have the same Uri format for later processing
func NormaliseUri(uri string) string {

	if len(uri) < 1 {
		return uri
	}

	if uri[0] == '/' {
		uri = uri[1:]
	}

	if uri[len(uri)-1] == '/' {
		uri = uri[0 : len(uri)-1]
	}

	return uri
}

// FetchGetData extracts the GET data
// from an HTTP request
func FetchGetData(req *http.Request) map[string]interface{} {

	res := make(map[string]interface{})

	for name, value := range req.URL.Query() {
		res[name] = value
	}

	return res

}

// FetchFormData extracts FORM data
//
// - parse 'form-data' if not supported (not POST requests)
// - parse 'x-www-form-urlencoded'
// - parse 'application/json'
func FetchFormData(req *http.Request) map[string]interface{} {

	res := make(map[string]interface{})

	ct := req.Header.Get("Content-Type")

	if strings.HasPrefix(ct, "application/json") {

		receiver := make(map[string]interface{}, 0)

		// 1. Init JSON reader
		decoder := json.NewDecoder(req.Body)
		if err := decoder.Decode(&receiver); err != nil {
			log.Printf("[parse.json] %s\n", err)
			return res
		}

		// 2. Return result
		return receiver

	} else if strings.HasPrefix(ct, "application/x-www-form-urlencoded") {

		// 1. Parse url encoded data
		req.ParseForm()

		// 2. Extract values
		for name, value := range req.PostForm {
			res[name] = value
		}

	} else { // form-data or anything

		// 1. Parse form-data
		if err := req.ParseMultipartForm(math.MaxInt32); err != nil {
			log.Printf("[read.multipart] %s\n", err)
			return res
		}

		// 2. Extract values
		for name, value := range req.PostForm {
			res[name] = value
		}

	}

	return res
}