package functions

// HTTP helper functions doing the input checking and calling the actual math functions

import (
	"fmt"
	"net/http"
	"strconv"
)

func HttpAbort(w http.ResponseWriter, code int, message string) {
	w.WriteHeader(code)
	fmt.Fprint(w, message)
}

func HttpGetPostInt(request *http.Request, key string) (value int, error error) {
	switch request.Method {
	case "POST":
		error = request.ParseForm()
		if error != nil {
			error = fmt.Errorf("unable to parse post input: %s",
				error.Error())
			return
		}
		value, error = strconv.Atoi(request.Form.Get(key))
		if error != nil {
			fmt.Printf("Error parsing parameter '%s'\n", key)
			error = fmt.Errorf("unable to parse parameter '%s' as an integer: %s",
				key, error.Error())
		}
		return
	default:
		error = fmt.Errorf("this endpoint does not support %s operations", request.Method)
		return
	}
}

func HttFibonacci(w http.ResponseWriter, request *http.Request) {
	seq, error := HttpGetPostInt(request, "seq")
	if error != nil {
		HttpAbort(w, http.StatusBadRequest,
			fmt.Sprintf("Could not get parameter: %s", error.Error()))
	} else if seq < 1 {
		HttpAbort(w, http.StatusBadRequest,
			"Please provide a positive integer as the sequence number.\n")
	} else {
		fmt.Printf("Received request for Fibonacci Sequence Number %d\n",
			seq)
		value, error := MyFibonacci(seq)
		if error != nil {
			fmt.Printf("Error trying to Fibonacci %d: %s", seq, error)
			fmt.Fprintf(w, "Error trying to Fibonacci %d: %s", seq, error)
		} else {
		fmt.Fprintf(w, "Fibonacci sequence index [%d]: %d\n",
			seq, value)
		}
	}
}

func HttSum(w http.ResponseWriter, request *http.Request) {
	var errorstr string
	first, error := HttpGetPostInt(request, "first")
	if error != nil {
		errorstr = error.Error()
	}
	second, error := HttpGetPostInt(request, "second")
	if error != nil {
		errorstr = error.Error()
	}

	if errorstr != "" {
		HttpAbort(w, http.StatusBadRequest,
			fmt.Sprintf("Invalid input: %s\n", errorstr))
		return
	}
	fmt.Printf("Received a request to add %d and %d.\n", first, second)
	fmt.Fprintf(w, "The sum of %d and %d is %d.\n", first, second, sum(first, second))

}