main.go

package main

import (
	_ "expvar"
	"fmt"
	"log"
	"net/http"
	"os"
	"strings"
	"html/template"
)

var Port string
func init() {
	Port = os.Getenv("PORT")
	if Port == "" {
		Port = "9876"
	}
}

type HTMLPage struct {
	Title string
	URL string
}

//calculating collection name, queryType, remaining string
func calculateCollectionName(dbQuery string) (string, string, string) {

	var queryType, rem string
	fmt.Println("dbQuery > ", dbQuery)
	a := strings.Split(dbQuery, ".")
	fmt.Println("a : > ", a)
	a2 := strings.Split(a[1], ".")
	fmt.Println("a : > ", a2)
	a3 := strings.Split(a[2], "(")
	fmt.Println("a : > ", a3)
	a4 := strings.Split(a3[1], "{")
	fmt.Println("a : > ", a4)
	a5 := strings.Split(a4[0], "}")
	fmt.Println("a : > ", a5)
	//getting collection Name
	queryType = strings.Title(a3[0])

	rem = a3[1]
	//if rem contains array //append []int
	if strings.Contains(rem, "[") {

	}

	//return collectionName, QueryType
	return a2[0], queryType, rem
}

func calculateMonGoQuery(dbName, dbQuery string) (string, error) {

	//Possible Queries
	//1. Inserting Documents

	//MongoEx
	//Input :
	// 1. Db Name
	// 2. Query :  db.ships.insert({name:'USS Enterprise-D',operator:'Starfleet',type:'Explorer',class:'Galaxy',crew:750,codes:[10,11,12]})

	//GoEx
	//Output : session.DB("Test").C("ships").Insert({Name: "USS Enterprise-D", Operator: "Starfleet", Type: "Explorer", Class: "Galaxy", Crew : 750, Codes: []int{10, 11, 12}}

	//getting collectionName, queryType and remaining string to be appended in answer
	collectionName, queryType, rem := calculateCollectionName(dbQuery)

	outputString := "session.DB(\"" + dbName + "\").C(\"" + collectionName + "\")." + queryType + "(" + rem

	return outputString, nil

	//2. Finding Documents
	//3. Finding Documents using Operators
	//3.1 $gt / $gte || $lt / $lte - greater than / greater than equals , lesser than / lesser than equals
	//3.2 $exists - does an attribute exist or not
	//3.3 $regex - Perl-style pattern matching
	//3.4 $type - search by type of an element

	//4. Updating Documents
	//5. Removing Documents
	//6. Working with Indexes
	//7. Pipeline Stages
	//7.1 $project
	//7.2 $match
	//7.3 $group
	//7.4 $sort
	//7.5 $skip
	//7.6 $limit
	//7.7 $unwind
	//8. Aggregation Expressions
	//8.1 $sum
	//8.2 $avg
	//8.3 $min / $max
	//8.4 $push
	//8.5 $addToSet
	//8.6 $first / $last

}

func Convert(w http.ResponseWriter, r *http.Request) {

	//fmt.Println("inside convert ")
	//fmt.Println("r >", r.Method)

	var dbName, dbQuery, generateButton string

	if r.Method == "GET" {
		template :=  template.Must(template.ParseFiles("index.html"))
		myvar := HTMLPage{Title:"Query Translater", URL: "https://cryptic-ravine-58923.herokuapp.com/"}
		e := template.ExecuteTemplate(w, "index.html", myvar)
		if e != nil {
			fmt.Println("ewewewewewe getting error", e.Error())
		}

	} else {

		// Form submitted
		r.ParseMultipartForm(32 << 20)
		//validation :  len(r.Form["username"][0])

		dbName = r.FormValue("dbName")
		if len(dbName) == 0 {
			fmt.Fprint(w, "dbName cannot be empty")
			os.Exit(0)
		}
		fmt.Fprintln(w, "Entered dbName is  :", dbName)

		dbQuery = r.FormValue("dbQuery")
		fmt.Fprintln(w, "Entered query is  :", dbQuery)

		ans, err := calculateMonGoQuery(dbName, dbQuery)
		if err != nil {
			log.Println("calculateMonGoQuery Error", err.Error())
		}

		fmt.Fprint(w, "outputString > "+ans)

		//POST : generate button action
		generateButton = r.FormValue("generate")

		//check if button is pressed
		if len(generateButton) != 0 {

			ans, err := calculateMonGoQuery(dbName, dbQuery)
			if err != nil {
				log.Println("calculateMonGoQuery Error", err.Error())
			}

			fmt.Fprint(w, ans)
		} else {
			fmt.Println("generatebutton is not pressed!")
			//fmt.lo(w , "generatebutton is not pressed!")
		}
	}
}

func handler(w http.ResponseWriter, r *http.Request) {
	http.ServeFile(w, r, "index.html")

	var dbName, dbQuery string

	// Form submitted
	r.ParseMultipartForm(32 << 20)
	//validation :  len(r.Form["username"][0])

	dbName = r.FormValue("dbName")
	if len(dbName) == 0 {
		fmt.Fprint(w, "dbName cannot be empty")
		os.Exit(0)
	}
	fmt.Fprint(w, "Entered dbName is  :", dbName)

	dbQuery = r.FormValue("dbQuery")
	fmt.Fprint(w, "Entered query is  :", dbQuery)

}

func main() {
	http.HandleFunc("/", Convert)
	//http.HandleFunc("/tt", handler)
	log.Println("Listening....on port: " + Port)
	http.ListenAndServe(":"+Port, nil)
}