package api

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"strconv"

	"srs.epita.fr/fic-server/libfic"

	"github.com/gorilla/mux"
)


type DispatchFunction func([]string, []byte) (interface{}, error)

func apiHandler(f func (map[string]string,[]byte) (interface{}, error)) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		log.Printf("Handling %s request from %s: %s [%s]\n", r.Method, r.RemoteAddr, r.URL.Path, r.UserAgent())

		w.Header().Set("Content-Type", "application/json")

		var ret interface{}
		var err error = nil

		// Read the body
		if r.ContentLength < 0 || r.ContentLength > 6553600 {
			http.Error(w, fmt.Sprintf("{errmsg:\"Request too large or request size unknown\"}", err), http.StatusRequestEntityTooLarge)
			return
		}
		var body []byte
		if r.ContentLength > 0 {
			tmp := make([]byte, 1024)
			for {
				n, err := r.Body.Read(tmp)
				for j := 0; j < n; j++ {
					body = append(body, tmp[j])
				}
				if err != nil || n <= 0 {
					break
				}
			}
		}

		ret, err = f(mux.Vars(r), body)

		// Format response
		resStatus := http.StatusOK
		if err != nil {
			ret = map[string]string{"errmsg": err.Error()}
			resStatus = http.StatusBadRequest
			log.Println(r.RemoteAddr, resStatus, err.Error())
		}

		if ret == nil {
			ret = map[string]string{"errmsg": "Page not found"}
			resStatus = http.StatusNotFound
		}

		if str, found := ret.(string); found {
			w.WriteHeader(resStatus)
			io.WriteString(w, str)
		} else if bts, found := ret.([]byte); found {
			w.WriteHeader(resStatus)
			w.Write(bts)
		} else if j, err := json.Marshal(ret); err != nil {
			http.Error(w, fmt.Sprintf("{\"errmsg\":\"%q\"}", err), http.StatusInternalServerError)
		} else {
			w.WriteHeader(resStatus)
			w.Write(j)
		}
	}
}

func teamHandler(f func(fic.Team,map[string]string,[]byte) (interface{}, error)) func (map[string]string,[]byte) (interface{}, error) {
	return func (args map[string]string, body []byte) (interface{}, error) {
		if tid, err := strconv.Atoi(string(args["tid"])); err != nil {
			if team, err := fic.GetTeamByInitialName(args["tid"]); err != nil {
				return nil, err
			} else {
				return f(team, args, body)
			}
		} else if team, err := fic.GetTeam(tid); err != nil {
			return nil, err
		} else {
			return f(team, args, body)
		}
	}
}

func themeHandler(f func(fic.Theme,map[string]string,[]byte) (interface{}, error)) func (map[string]string,[]byte) (interface{}, error) {
	return func (args map[string]string, body []byte) (interface{}, error) {
		if tid, err := strconv.Atoi(string(args["tid"])); err != nil {
			return nil, err
		} else if theme, err := fic.GetTheme(tid); err != nil {
			return nil, err
		} else {
			return f(theme, args, body)
		}
	}
}

func exerciceHandler(f func(fic.Exercice,map[string]string,[]byte) (interface{}, error)) func (map[string]string,[]byte) (interface{}, error) {
	return func (args map[string]string, body []byte) (interface{}, error) {
		if eid, err := strconv.Atoi(string(args["eid"])); err != nil {
			return nil, err
		} else if exercice, err := fic.GetExercice(int64(eid)); err != nil {
			return nil, err
		} else {
			return f(exercice, args, body)
		}
	}
}

func themedExerciceHandler(f func(fic.Theme,fic.Exercice,map[string]string,[]byte) (interface{}, error)) func (fic.Theme,map[string]string,[]byte) (interface{}, error) {
	return func (theme fic.Theme, args map[string]string, body []byte) (interface{}, error) {
		if eid, err := strconv.Atoi(string(args["eid"])); err != nil {
			return nil, err
		} else if exercice, err := fic.GetExercice(int64(eid)); err != nil {
			return nil, err
		} else {
			return f(theme, exercice, args, body)
		}
	}
}

func notFound(args map[string]string, body []byte) (interface{}, error) {
	return nil, nil
}