package api

import (
	"encoding/json"
	"io/ioutil"
	"net/http"

	"code.osinet.fr/fgm/kurz/domain"
)

const postContentType = "application/json"

func jsonFromString(s string) []byte {
	j, err := json.Marshal(Target{})
	if err != nil {
		panic(err)
	}
	return j
}

// handlePostTarget() handles "POST /" with { "target": "some target" }.
func handlePostTarget(w http.ResponseWriter, r *http.Request) {
	payload, err := ioutil.ReadAll(r.Body)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write(jsonFromString(`{ error: "Incomplete request body"}`))
		return
	}
	var target Target
	err = json.Unmarshal(payload, &target)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write(jsonFromString(`{ error: "Invalid JSON request"}`))
		return
	}

	shortString, isNew, err := domain.GetShortURL(target.Target)

	w.Header().Set("Content-type", postContentType)

	if err != nil {
		domainErr, ok := err.(domain.Error)
		if ok {
			switch domainErr.Kind {
			case domain.TargetInvalidError:
				w.WriteHeader(http.StatusBadRequest)
				w.Write(jsonFromString(`{ error: "Invalid target requested"}`))

			// Covers all the domain.Storage* error cases too.
			default:
				w.WriteHeader(http.StatusInternalServerError)
			}
		} else {
			w.WriteHeader(http.StatusInternalServerError)
		}

		return
	}

	short := Short{Short: shortString}
	payload, err = json.Marshal(short)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write(jsonFromString(`{ error: "Short URL serialization error"}`))
		return
	}

	if isNew {
		w.WriteHeader(http.StatusCreated)
	} else {
		w.WriteHeader(http.StatusConflict)
	}

	w.Write(payload)
	return
}