// NGnius 2020-01-30

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"strconv"
	"strings"
)

const (
	defaultCorsHeader = "*"
	defaultPassword   = ""
)

var (
	corsHeader  string
	password    string
	reuseTokens bool
)

func boardHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	w.Header().Add("Access-Control-Allow-Origin", corsHeader)
	if r.Method != "GET" {
		//w.WriteHeader(405)
		errorResponse(405, "Non-GET method not allowed at this endpoint", w, r)
		return
	}
	args := r.URL.Query()
	// check args pre-conditions
	if !checkArgExists(args, "board", w) {
		errorResponse(400, "Missing required 'board' URL parameter", w, r)
		return
	}
	board := args.Get("board")
	if !checkArgExists(args, "count", w) || !checkArgInt(args, "count", w, 0) {
		//w.WriteHeader(400)
		errorResponse(400, "Missing required 'count' integer URL parameter", w, r)
		return
	}
	count, _ := strconv.Atoi(args.Get("count"))
	if !checkArgExists(args, "start", w) || !checkArgInt(args, "start", w, 0) {
		//w.WriteHeader(400)
		errorResponse(400, "Missing required 'start' integer URL parameter", w, r)
		return
	}
	start, _ := strconv.Atoi(args.Get("start"))
	// execute query
	result := NewResult("", r.URL.String())
	b, err := boardByName(board)
	//b, ok := boards[board]
	if err != nil {
		fmt.Println(err)
		//w.WriteHeader(404)
		errorResponse(404, "Board could not be retrieved: "+err.Error(), w, r)
		return
	}
	bEntries, loadErr := b.SomeEntries(int64(start), int64(start+count))
	if loadErr != nil {
		fmt.Println(loadErr)
		//w.WriteHeader(404)
		errorResponse(404, "Board entries could not be retrieved: "+loadErr.Error(), w, r)
		return
	}
	for _, entry := range bEntries {
		item, entryErr := entry.JsonObject()
		if entryErr != nil {
			fmt.Println(entryErr)
		}
		result.Items = append(result.Items, &item)
	}
	result.Query = fmt.Sprintf("load board[name: %s] from %d to %d", board, start, count+start)
	result.Complete()
	data, err := json.Marshal(result)
	if err != nil {
		//w.WriteHeader(500)
		errorResponse(500, "Unable to convert result into JSON: "+err.Error(), w, r)
		return
	}
	w.Write(data)
}

func playerHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	w.Header().Add("Access-Control-Allow-Origin", corsHeader)
	if r.Method != "GET" {
		//w.WriteHeader(405)
		errorResponse(405, "Non-GET method not allowed at this endpoint", w, r)
		return
	}
	args := r.URL.Query()
	// check args
	if !checkArgExists(args, "id", w) || !checkArgInt(args, "id", w, 1) {
		errorResponse(400, "Missing required 'id' integer URL parameter", w, r)
		return
	}
	id, _ := strconv.Atoi(args.Get("id"))
	entry_count := 0
	if checkArgExists(args, "entries", w) && checkArgInt(args, "entries", w, 0) {
		entry_count, _ = strconv.Atoi(args.Get("entries"))
	}
	// retrieve player
	result := NewResult("", r.URL.String())
	player := &Player{ID: int64(id)}
	loadErr := player.Load()
	if loadErr != nil {
		fmt.Println(loadErr)
		//w.WriteHeader(404)
		errorResponse(404, "Player could not be retrieved: "+loadErr.Error(), w, r)
		return
	}
	tempJsonObj, _ := player.JsonObject()
	pJsonObj := tempJsonObj.(PlayerJSON)
	if entry_count > 0 {
		entries, loadErr := player.SomeEntries(int64(entry_count))
		if loadErr == nil {
			for _, e := range entries {
				eJsonObj, entryErr := e.JsonObject()
				if entryErr != nil {
					fmt.Println(entryErr)
				}
				pJsonObj.Entries = append(pJsonObj.Entries, eJsonObj.(EntryJSON))
			}
		}
	}
	result.Items = []interface{}{pJsonObj}
	result.Query = fmt.Sprintf("load player[id: %d]", player.ID)
	result.Complete()
	data, err := json.Marshal(result)
	if err != nil {
		//w.WriteHeader(500)
		errorResponse(500, "Unable convert result to JSON: "+err.Error(), w, r)
		return
	}
	w.Write(data)
}

func newEntryHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	w.Header().Add("Access-Control-Allow-Origin", corsHeader)
	if r.Method != "POST" {
		//w.WriteHeader(405)
		errorResponse(405, "Non-POST method not allowed at this endpoint", w, r)
		return
	}
	// check for API token
	tokenHeader := r.Header.Get("Authorization")
	tokenSplit := strings.Split(tokenHeader, " ")
	if tokenHeader == "" || len(tokenSplit) != 2 || tokenSplit[1] == "" {
		errorResponse(401, "Missing or invalid authorization header", w, r)
		return
	}
	key, keyErr := keyByToken(tokenSplit[1])
	if keyErr != nil || key.ID == 0 {
		errorResponse(401, "Invalid token", w, r)
		return
	}
	if !key.IsEnabled() {
		errorResponse(403, "Invalid token", w, r)
		return
	}
	data, readErr := ioutil.ReadAll(r.Body)
	if readErr != nil {
		fmt.Println(readErr)
		//w.WriteHeader(500)
		errorResponse(500, "Unable to read HTTP request body: "+readErr.Error(), w, r)
		return
	}
	newEntry, jsonErr := UnmarshalNewEntryJSON(data)
	if jsonErr != nil {
		//w.WriteHeader(400)
		errorResponse(400, "Unable to convert request to JSON: "+jsonErr.Error(), w, r)
		return
	}
	if password != "" && newEntry.Password != password {
		errorResponse(403, "Invalid password", w, r)
		return
	}
	if newEntry.PlayerID != key.Player && !key.IsMultiuser() {
		errorResponse(403, "Invalid authorization for player", w, r)
		return
	}
	sqlErr := newEntrySql(newEntry.Score, newEntry.PlayerID, newEntry.BoardID)
	if sqlErr != nil {
		fmt.Println(sqlErr)
		//w.WriteHeader(500)
		errorResponse(500, "Entry could not be created: "+sqlErr.Error(), w, r)
		return
	}
	//w.WriteHeader(204)
	errorResponse(200, "New entry created", w, r)
}

func newKeyHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	w.Header().Add("Access-Control-Allow-Origin", corsHeader)
	if r.Method != "POST" {
		errorResponse(405, "Non-POST method not allowed at this endpoint", w, r)
		return
	}
	data, readErr := ioutil.ReadAll(r.Body)
	if readErr != nil {
		fmt.Println(readErr)
		errorResponse(500, "Unable to read HTTP request body: "+readErr.Error(), w, r)
		return
	}
	result := NewResult("", r.URL.String())
	newKey, jsonErr := UnmarshalNewKeyJSON(data)
	if jsonErr != nil {
		errorResponse(400, "Unable to convert request to JSON: "+jsonErr.Error(), w, r)
		return
	}
	var key *Key
	var sqlErr error
	if reuseTokens {
		key, sqlErr = keyByPlayer(newKey.PlayerID)
	}
	if (sqlErr != nil && reuseTokens) || !reuseTokens {
		key, sqlErr = newKeySql(newKey.PlayerID)
	}
	if sqlErr != nil {
		fmt.Println(sqlErr)
		errorResponse(500, "Key could not be created: "+sqlErr.Error(), w, r)
		return
	}
	jsonObj, _ := key.JsonObject()
	result.Items = []interface{}{jsonObj}
	result.Query = fmt.Sprintf("new key[player id: %d]", newKey.PlayerID)
	result.Complete()
	data, err := json.Marshal(result)
	if err != nil {
		errorResponse(500, "Unable convert result to JSON: "+err.Error(), w, r)
		return
	}
	w.Write(data)
}

func exampleHandler(w http.ResponseWriter, r *http.Request) {
	// useless function please ignore
}

// utility functions

func checkArgExists(values url.Values, key string, w http.ResponseWriter) (ok bool) {
	ok = values.Get(key) != ""
	return
}

func checkArgInt(values url.Values, key string, w http.ResponseWriter, min int) (ok bool) {
	intVal, err := strconv.Atoi(values.Get(key))
	ok = err == nil && intVal >= min
	return
}

func errorResponse(statusCode int, reason string, w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(statusCode)
	query := "error"
	if statusCode == 200 {
		query = "success"
	}
	errorRes := NewResult(query, r.URL.String())
	errorRes.Items = append(errorRes.Items, ErrorJSON{Reason: reason, StatusCode: statusCode})
	errorRes.StatusCode = statusCode
	data, _ := json.Marshal(errorRes)
	w.Write(data)
}