package core

import (
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"net/http"
	"sort"
	"strings"
	"sync/atomic"
	"time"
	"unsafe"

	"repositories.action2quare.com/ayo/go-ayo/common"
	"repositories.action2quare.com/ayo/go-ayo/logger"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo/options"
)

func (caller apiCaller) isGlobalAdmin() bool {
	if *noauth {
		return true
	}

	email, ok := caller.userinfo["email"]
	if !ok {
		return false
	}

	if _, ok := caller.admins[email.(string)]; ok {
		return true
	}

	return false
}

func (caller apiCaller) writeAccessableServices(w http.ResponseWriter) {
	services, editable := caller.getAccessableServices()
	for _, r := range editable {
		w.Header().Add("MG-X-SERVICE-EDITABLE", r)
	}

	w.Write([]byte("{"))
	start := true
	for _, v := range services {
		if !start {
			w.Write([]byte(","))
		}
		w.Write([]byte(fmt.Sprintf(`"%s":`, v.ServiceName)))
		serptr := atomic.LoadPointer(&v.serviceSerialized)
		w.Write(*(*[]byte)(serptr))
		start = false
	}
	w.Write([]byte("}"))
}

func (caller apiCaller) getAccessableServices() ([]*serviceDescription, []string) {
	allservices := caller.mg.services.all()
	v, ok := caller.userinfo["email"]
	if !ok {
		return nil, nil
	}

	email := v.(string)
	_, admin := caller.admins[email]

	var output []*serviceDescription
	var editable []string
	for _, desc := range allservices {
		if admin {
			output = append(output, desc)
			editable = append(editable, desc.ServiceName)
		} else if desc.isValidAPIUser("*", email) {
			output = append(output, desc)
			if desc.isValidAPIUser("service", email) {
				editable = append(editable, desc.ServiceName)
			}
		}
	}

	sort.Slice(output, func(i, j int) bool {
		return output[i].ServiceName < output[j].ServiceName
	})

	return output, editable
}

func (caller apiCaller) isValidUser(service any, category string) (valid bool, admin bool) {
	if *noauth {
		return true, true
	}

	v, ok := caller.userinfo["email"]
	if !ok {
		logger.Println("isVaidUser failed. email is missing :", caller.userinfo)
		return false, false
	}

	email := v.(string)
	if _, ok := caller.admins[email]; ok {
		return true, true
	}

	svcdesc := caller.mg.services.get(service)
	if svcdesc == nil {
		logger.Println("isVaidUser failed. service is missing :", service)
		return false, false
	}

	return svcdesc.isValidAPIUser(category, email), false
}

func (caller apiCaller) whitelistAPI(w http.ResponseWriter, r *http.Request) error {
	mg := caller.mg
	queryvals := r.URL.Query()
	if r.Method == "GET" {
		service := queryvals.Get("service")

		if valid, _ := caller.isValidUser(service, "whitelist"); !valid {
			logger.Println("whitelistAPI failed. not vaild user :", r.Method, caller.userinfo)
			w.WriteHeader(http.StatusBadRequest)
			return nil
		}

		if len(service) > 0 {

			all, err := mg.mongoClient.FindAll(CollectionWhitelist, bson.M{
				"service": service,
			})
			if err != nil {
				return err
			}

			if len(all) > 0 {
				allraw, _ := json.Marshal(all)
				w.Write(allraw)
			}
		} else {
			logger.Println("service param is missing")
		}
	} else if r.Method == "PUT" {
		body, _ := io.ReadAll(r.Body)
		var member whitelistmember
		if err := json.Unmarshal(body, &member); err != nil {
			return err
		}
		if valid, _ := caller.isValidUser(member.Service, "whitelist"); !valid {
			logger.Println("whitelistAPI failed. not vaild user :", r.Method, caller.userinfo)
			w.WriteHeader(http.StatusBadRequest)
			return nil
		}

		member.Expired = 0

		_, _, err := mg.mongoClient.Update(CollectionWhitelist, bson.M{
			"_id": primitive.NewObjectID(),
		}, bson.M{
			"$set": &member,
		}, options.Update().SetUpsert(true))

		if err != nil {
			return err
		}
	} else if r.Method == "DELETE" {
		id := queryvals.Get("id")
		if len(id) == 0 {
			return errors.New("id param is missing")
		}
		idobj, err := primitive.ObjectIDFromHex(id)
		if err != nil {
			return err
		}

		_, _, err = mg.mongoClient.Update(CollectionWhitelist, bson.M{
			"_id": idobj,
		}, bson.M{
			"$currentDate": bson.M{
				"_ts": bson.M{"$type": "date"},
			},
		}, options.Update().SetUpsert(false))
		if err != nil {
			return err
		}
	}
	return nil
}

func (caller apiCaller) serviceAPI(w http.ResponseWriter, r *http.Request) error {
	mg := caller.mg
	queryvals := r.URL.Query()
	if r.Method == "GET" {
		name := queryvals.Get("name")
		if len(name) > 0 {
			if valid, _ := caller.isValidUser(name, "*"); !valid {
				logger.Println("serviceAPI failed. not vaild user :", r.Method, caller.userinfo)
				w.WriteHeader(http.StatusBadRequest)
				return nil
			}

			if valid, admin := caller.isValidUser(name, "service"); valid || admin {
				w.Header().Add("MG-X-SERVICE-EDITABLE", name)
			}

			serptr := atomic.LoadPointer(&mg.services.get(name).serviceSerialized)
			w.Write(*(*[]byte)(serptr))
		} else {
			caller.writeAccessableServices(w)
		}
	} else if r.Method == "POST" {
		body, _ := io.ReadAll(r.Body)
		var service serviceDescription
		if err := json.Unmarshal(body, &service); err != nil {
			return err
		}

		if service.Id.IsZero() {
			if caller.isGlobalAdmin() {
				service.Id = primitive.NewObjectID()
			} else {
				logger.Println("serviceAPI failed. not vaild user :", r.Method, caller.userinfo)
				w.WriteHeader(http.StatusBadRequest)
				return nil
			}
		} else if valid, _ := caller.isValidUser(service.Id, "service"); !valid {
			logger.Println("serviceAPI failed. not vaild user :", r.Method, caller.userinfo)
			w.WriteHeader(http.StatusBadRequest)
			return nil
		}

		filter := bson.M{"_id": service.Id}
		success, _, err := mg.mongoClient.Update(CollectionService, filter, bson.M{
			"$set": &service,
		}, options.Update().SetUpsert(true))

		if err != nil {
			return err
		}

		if !success {
			logger.Println("serviceAPI failed. not vaild user :", caller.userinfo)
			w.WriteHeader(http.StatusBadRequest)
		}
	}

	return nil
}

func (caller apiCaller) accountAPI(w http.ResponseWriter, r *http.Request) error {
	mg := caller.mg
	queryvals := r.URL.Query()
	if r.Method == "GET" {
		service := queryvals.Get("service")
		if len(service) == 0 {
			return nil
		}

		if valid, _ := caller.isValidUser(service, "account"); !valid {
			logger.Println("accountAPI failed. not vaild user :", r.Method, caller.userinfo)
			w.WriteHeader(http.StatusBadRequest)
			return nil
		}

		var accdoc primitive.M
		if v := queryvals.Get("accid"); len(v) == 0 {
			email := queryvals.Get("email")
			platform := queryvals.Get("platform")
			if len(email) == 0 || len(platform) == 0 {
				return nil
			}

			found, err := mg.mongoClient.FindOne(CollectionLink, bson.M{
				"email":    email,
				"platform": platform,
			})
			if err != nil {
				return err
			}
			if found == nil {
				return nil
			}
			if idobj, ok := found["_id"]; ok {
				svcdoc, err := mg.mongoClient.FindOne(common.CollectionName(service), bson.M{
					"_id": idobj,
				})
				if err != nil {
					return err
				}
				if svcdoc != nil {
					found["accid"] = svcdoc["accid"]
				}

				accdoc = found
			}
		} else {
			accid, err := primitive.ObjectIDFromHex(v)
			if err != nil {
				return err
			}

			svcdoc, err := mg.mongoClient.FindOne(common.CollectionName(service), bson.M{
				"accid": accid,
			})
			if err != nil {
				return err
			}

			found, err := mg.mongoClient.FindOne(CollectionLink, bson.M{
				"_id": svcdoc["_id"],
			})
			if err != nil {
				return err
			}

			if found != nil {
				found["accid"] = accid
			}
			accdoc = found
		}

		if accdoc != nil {
			accdoc["code"] = service
			delete(accdoc, "uid")
			delete(accdoc, "_id")

			var bi blockinfo
			if err := mg.mongoClient.FindOneAs(CollectionBlock, bson.M{
				"code":  service,
				"accid": accdoc["accid"],
			}, &bi); err != nil {
				return err
			}

			if !bi.Start.Time().IsZero() && bi.End.Time().After(time.Now().UTC()) {
				accdoc["blocked"] = bi
			}
			return json.NewEncoder(w).Encode(accdoc)
		}
	} else if r.Method == "POST" {
		var account struct {
			Code    string
			Accid   string
			Blocked blockinfo
		}

		body, _ := io.ReadAll(r.Body)
		if err := json.Unmarshal(body, &account); err != nil {
			return err
		}

		accid, _ := primitive.ObjectIDFromHex(account.Accid)
		if !account.Blocked.Start.Time().IsZero() && account.Blocked.Start.Time().After(time.Now().UTC()) {
			if _, _, err := mg.mongoClient.Update(CollectionBlock, bson.M{
				"code":  account.Code,
				"accid": accid,
			}, bson.M{
				"$set": account.Blocked,
			}, options.Update().SetUpsert(true)); err != nil {
				return err
			}
		}
	}
	return nil
}

var errApiTokenMissing = errors.New("mg-x-api-token is missing")

func (caller apiCaller) configAPI(w http.ResponseWriter, r *http.Request) error {
	mg := caller.mg
	apitoken := r.Header.Get("MG-X-API-TOKEN")
	if len(apitoken) == 0 {
		return errApiTokenMissing
	}

	if _, exists := mg.apiTokenToService.get(apitoken); !exists {
		return fmt.Errorf("mg-x-api-token is not valid : %s", apitoken)
	}

	return nil
}

var noauth = flag.Bool("noauth", false, "")

type apiCaller struct {
	userinfo map[string]any
	admins   map[string]bool
	mg       *Maingate
}

func (mg *Maingate) api(w http.ResponseWriter, r *http.Request) {
	defer func() {
		s := recover()
		if s != nil {
			logger.Error(s)
		}
	}()

	defer func() {
		io.Copy(io.Discard, r.Body)
		r.Body.Close()
	}()

	var userinfo map[string]any

	if !*noauth {
		authheader := r.Header.Get("Authorization")
		if len(authheader) == 0 {
			logger.Println("Authorization header is not valid :", authheader)
			w.WriteHeader(http.StatusBadRequest)
			return
		}

		req, _ := http.NewRequest("GET", "https://graph.microsoft.com/oidc/userinfo", nil)
		req.Header.Add("Authorization", authheader)
		client := &http.Client{}

		resp, err := client.Do(req)
		if err != nil {
			logger.Println("graph microsoft api call failed :", err)
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		defer resp.Body.Close()

		raw, _ := io.ReadAll(resp.Body)
		if err = json.Unmarshal(raw, &userinfo); err != nil {
			return
		}

		if _, expired := userinfo["error"]; expired {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}
	}

	ptr := atomic.LoadPointer(&mg.admins)
	adminsptr := (*globalAdmins)(ptr)

	if adminsptr.modtime != common.ConfigModTime() {
		var config globalAdmins
		if err := common.LoadConfig(&config); err == nil {
			config.parse()
			adminsptr = &config
			atomic.StorePointer(&mg.admins, unsafe.Pointer(adminsptr))
		}
	}

	logger.Println("api call :", r.URL.Path, r.Method, r.URL.Query(), userinfo)
	caller := apiCaller{
		userinfo: userinfo,
		admins:   adminsptr.emails,
		mg:       mg,
	}

	var err error
	if strings.HasSuffix(r.URL.Path, "/service") {
		err = caller.serviceAPI(w, r)
	} else if strings.HasSuffix(r.URL.Path, "/whitelist") {
		err = caller.whitelistAPI(w, r)
	} else if strings.HasSuffix(r.URL.Path, "/config") {
		err = caller.configAPI(w, r)
	} else if strings.HasSuffix(r.URL.Path, "/account") {
		err = caller.accountAPI(w, r)
	}

	if err != nil {
		logger.Error(err)
	}
}