package main

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"strconv"

	//"io"
	"log"
	"net/http"

	// "os"
	// "os/signal"
	// "reflect"
	"math/rand"
	"strings"

	// "sync"
	// "time"
	"github.com/gorilla/mux"
	"github.com/neo4j/neo4j-go-driver/v5/neo4j"
)

func id_exists(id int, driver neo4j.DriverWithContext, driver_ctx context.Context) bool {
	result, _ := neo4j.ExecuteQuery(driver_ctx, driver,
		"MATCH (u:User) WHERE id(u) = $id RETURN count(u)",
		map[string]any{
			"id": id,
		}, neo4j.EagerResultTransformer,
		neo4j.ExecuteQueryWithDatabase("neo4j"))

	if len(result.Records) > 0 {
		return true
	} else {
		return false
	}
}

func create_new_user(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")

		err := r.ParseMultipartForm(10 << 20) // Limit to 10MB
		if err != nil {
			log.Println("Unable to parse form.")
		}

		username := r.FormValue("username")
		email := r.FormValue("email")
		password_hash := r.FormValue("password_hash")

		id := rand.Intn(999999999999) + 1
		for id_exists(id, driver, driver_ctx) {
			id = rand.Intn(999999999999) + 1
		}

		profile_picture_file, header, err := r.FormFile("profile_picture")
		if err != nil {
			log.Println("Error retrieving file from form.")
		}

		defer profile_picture_file.Close()
		filename_parts := strings.Split(header.Filename, ".")
		ext := filename_parts[len(filename_parts)-1]

		dst, err := os.Create(os.Getenv("PROFILE_IMAGES_FQ_PATH") + strconv.Itoa(id) + ext)
		if err != nil {
			log.Println("Error saving profile picture.")
		}
		defer dst.Close()

		_, err = io.Copy(dst, profile_picture_file)
		if err != nil {
			log.Println("Error writing file to filesystem.")
		}

		result, _ := neo4j.ExecuteQuery(driver_ctx, driver,
			"CREATE (u:User {id: $id, username: $username, email: $email, password_hash: $password_hash, profile_picture: $profile_picture, created_at: datetime()})-[:USER_TYPE]->(:Role {name: 'User'}) RETURN elementId(u) AS id",
			map[string]any{
				"id":              id,
				"username":        username,
				"email":           email,
				"password_hash":   password_hash,
				"profile_picture": strconv.Itoa(id) + ext,
			}, neo4j.EagerResultTransformer,
			neo4j.ExecuteQueryWithDatabase("neo4j"))

		if len(result.Records) > 0 {
			ret := struct {
				Auth bool   `json:"auth"`
				Id   string `json:"id"`
			}{
				Auth: true,
				Id:   strconv.Itoa(id),
			}

			json, err := json.Marshal(ret)
			if err != nil {
				return
			}

			w.WriteHeader(http.StatusOK)
			w.Header().Set("Content-Type", "application/json")
			fmt.Fprintf(w, string(json))
			log.Println("User ID:", id, "Action: Signup")
		} else {
			return
		}
	}
}

func retrieve_all_users(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		return
	}
}

func retrieve_user(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		id, _ := strconv.Atoi(mux.Vars(r)["user_id"])

		result, _ := neo4j.ExecuteQuery(driver_ctx, driver,
			"MATCH (u:User) WHERE id(u) = $user_id RETURN u.username AS username, u.email AS email, u.profile_picture AS profile_picture",
			map[string]any{
				"user_id": id,
			}, neo4j.EagerResultTransformer,
			neo4j.ExecuteQueryWithDatabase("neo4j"))

		if len(result.Records) > 0 {
			record := result.Records[0]
			vals := record.AsMap()
			user := struct {
				Username       string `json:"username"`
				Email          string `json:"email"`
				ProfilePicture string `json:"profile_picture"`
			}{
				Username:       vals["username"].(string),
				Email:          vals["email"].(string),
				ProfilePicture: vals["profile_picture"].(string),
			}

			json, err := json.Marshal(user)
			if err != nil {
				return
			}

			w.WriteHeader(http.StatusOK)
			w.Header().Set("Content-Type", "application/json")
			fmt.Fprintf(w, string(json))
			log.Println("User ID:", id, "Action: Retrieval")
		} else {
			return
		}
	}
}

func auth_user(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")

		username := r.FormValue("username")
		password_hash := r.FormValue("password_hash")

		result, _ := neo4j.ExecuteQuery(driver_ctx, driver,
			"MATCH (u:User) WHERE u.username = $username RETURN u.password_hash AS password_hash, elementId(u) AS id",
			map[string]any{
				"username": username,
			}, neo4j.EagerResultTransformer,
			neo4j.ExecuteQueryWithDatabase("neo4j"))

		if len(result.Records) > 0 {
			record := result.Records[0]
			vals := record.AsMap()
			if vals["password_hash"] != password_hash {
				return
			}

			id := strings.Split(vals["id"].(string), ":")[2]

			ret := struct {
				Auth bool   `json:"auth"`
				Id   string `json:"id"`
			}{
				Auth: true,
				Id:   id,
			}

			json, err := json.Marshal(ret)
			if err != nil {
				return
			}

			w.WriteHeader(http.StatusOK)
			w.Header().Set("Content-Type", "application/json")
			fmt.Fprintf(w, string(json))
			log.Println("User ID:", id, "Action: Login")
		} else {
			return
		}

	}
}

func update_user(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		return
	}
}

func delete_user(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		return
	}
}

func retrieve_users_posts(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		return
	}
}

func retrieve_users_spaces(driver neo4j.DriverWithContext, driver_ctx context.Context) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		return
	}
}