package cmd

import (
	"crypto/sha256"
	"database/sql"
	"encoding/hex"
	"fmt"
	"log"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
	_ "github.com/lib/pq"
	"github.com/spf13/viper"
)

var (
	ListenPort = "8080"

	db *sql.DB

	DB_Host string
	DB_Port string
	DB_User string
	DB_Pass string
	DB_Name string
)

func getDBInfo() error {
	dbhost := viper.GetString("Server.DB_Host")
	if dbhost == "" {
		e := fmt.Errorf("No database IP address present in config file!\n")
		return e
	} else {
		DB_Host = dbhost
	}

	dbport := viper.GetString("Server.DB_Port")
	if dbport == "" {
		e := fmt.Errorf("No database port present in config file!\n")
		return e
	} else {
		DB_Port = dbport
	}

	dbuser := viper.GetString("Server.DB_User")
	if dbuser == "" {
		e := fmt.Errorf("No database username present in config file!\n")
		return e
	} else {
		DB_User = dbuser
	}

	dbpass := viper.GetString("Server.DB_Pass")
	if dbpass == "" {
		e := fmt.Errorf("No database password present in config file!\n")
		return e
	} else {
		DB_Pass = dbpass
	}

	dbname := viper.GetString("Server.DB_Name")
	if dbname == "" {
		e := fmt.Errorf("No database name present in config file!\n")
		return e
	} else {
		DB_Name = dbname
	}
	return nil
}

func openDB() error {
	psqlconn := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=disable", DB_Host, DB_Port, DB_User, DB_Pass, DB_Name)
	dba, err := sql.Open("postgres", psqlconn)
	if err != nil {
		return err
	}
	db = dba
	return nil
}

func setPort() {
	p := viper.GetString("Server.Port")
	if p != "" {
		ListenPort = p
	}
}

func server() {
	log.SetPrefix("[DRAHOOT] ")
	setPort()
	if err := getDBInfo(); err != nil {
		log.Fatalf("INVALID DB INFO: %v\nPlease refer to the example configuration file in the repo at https://git.bulgariu.xyz/raul/drahoot/src/branch/main/sample-config (default config path = ~/.config/drahoot/drahoot.toml)", err)
	}
	if err := openDB(); err != nil {
		log.Fatalf("Error happened trying to connect to database: %v", err)
	}

	gin.SetMode(gin.ReleaseMode)
	r := gin.Default()
	r.GET("/", helloWorld)
	// TODO: Have fun creating new endpoints
	r.GET("/api/user", getUsers)
	r.GET("/api/user/:userid", getUser)
	r.POST("/api/user", createUser)
	r.DELETE("/api/user/:userid", deleteUser)

	r.Run(":" + ListenPort)
}

func hashPW(plain string) string {
	hashedPW := sha256.New()
	hashedPW.Write([]byte(plain))
	sha256hash := hex.EncodeToString(hashedPW.Sum(nil))

	return sha256hash
}

func deleteUser(c *gin.Context) {
	id := c.Param("userid")
	dynStmt := `DELETE FROM usuarios WHERE id_usuario = $1`

	_, err := strconv.Atoi(id)
	if err != nil {
		e := fmt.Sprintf("Invalid identifier")
		c.IndentedJSON(http.StatusNotFound, setResponse(e, false))
		return
	}

	_, err = db.Exec(dynStmt, id)
	if err != nil {
		e := fmt.Sprintf("Something went wrong trying to delete the user: %v", err)
		log.Println(e)
		c.IndentedJSON(http.StatusInternalServerError, setResponse(e, false))
		return
	}
	e := fmt.Sprintf("User successfully deleted")
	c.IndentedJSON(http.StatusOK, setResponse(e, true))
}

func createUser(c *gin.Context) {
	newuser := user{}
	if err := c.BindJSON(&newuser); err != nil {
		e := fmt.Sprintf("Something went wrong creating the user: %v", err)
		log.Println(e)
		c.IndentedJSON(http.StatusInternalServerError, setResponse(e, false))
		return
	}
	secret := hashPW(newuser.Password)
	var dynStmt string
	if newuser.AccountType != "estudiante" && newuser.AccountType != "profesor" {
		if newuser.AccountType == "admin" {
			e := fmt.Sprintf("Nice try (https://xkcd.com/327/)")
			c.IndentedJSON(http.StatusTeapot, setResponse(e, false))
			return
		}
		e := fmt.Sprintf("Invalid account type\n")
		c.IndentedJSON(http.StatusNotFound, setResponse(e, false))
		return
	}
	dynStmt = `INSERT INTO usuarios(nombre, apellido1, apellido2, email, password, rol) values($1, $2, $3, $4, $5, $6)`
	_, err := db.Exec(dynStmt, newuser.Name, newuser.Surname1, newuser.Surname2, newuser.Email, secret, newuser.AccountType)
	if err != nil {
		e := fmt.Sprintf("Something went wrong trying to create the user: %v", err)
		log.Println(e)
		c.IndentedJSON(http.StatusInternalServerError, setResponse(e, false))
		return
	}
	e := fmt.Sprintf("User %v has been created!", newuser.Name)
	c.IndentedJSON(http.StatusOK, setResponse(e, true))
}

func setResponse(content any, success bool) response {
	msg := response{Contents: content, Success: success}
	return msg
}

func getUser(c *gin.Context) {
	id := c.Param("userid")

	_, err := strconv.Atoi(id)
	if err != nil {
		e := fmt.Sprintf("Invalid identifier")
		c.IndentedJSON(http.StatusNotFound, setResponse(e, false))
		return
	}

	user := user{}
	dynStmt := `SELECT id_usuario,nombre,apellido1,apellido2,email,rol FROM usuarios WHERE id_usuario = $1`
	err = db.QueryRow(dynStmt, id).Scan(&user.Id, &user.Name, &user.Surname1, &user.Surname2, &user.Email, &user.AccountType)
	if err != nil {
		if err == sql.ErrNoRows {
			c.IndentedJSON(http.StatusNotFound, setResponse("User not found", false))
			return
		}
		e := fmt.Sprintf("SOMETHING BAD HAPPENED QUERYING THE DATABASE: %v", err)
		log.Println(e)
		c.IndentedJSON(http.StatusInternalServerError, setResponse(e, false))
		return
	}
	c.IndentedJSON(http.StatusOK, setResponse(user, true))
}

func getUsers(c *gin.Context) {
	users := []user{}
	rows, err := db.Query("SELECT id_usuario,nombre,apellido1,apellido2,email,rol FROM usuarios")
	if err != nil {
		e := fmt.Sprintf("SOMETHING BAD HAPPENED QUERYING THE DATABASE: %v", err)
		log.Println(e)
		c.IndentedJSON(http.StatusInternalServerError, setResponse(e, false))
		return
	}
	defer rows.Close()
	for rows.Next() {
		user := user{}
		err = rows.Scan(&user.Id, &user.Name, &user.Surname1, &user.Surname2, &user.Email, &user.AccountType)
		if err != nil {
			e := fmt.Sprintf("SOMETHING BAD HAPPENED SCANNING THE ROWS: %v", err)
			log.Println(e)
			c.IndentedJSON(http.StatusInternalServerError, setResponse(e, false))
			return
		}
		users = append(users, user)
	}
	c.IndentedJSON(http.StatusOK, setResponse(users, true))
}

func helloWorld(c *gin.Context) {
	ua := c.Request.UserAgent()
	message := fmt.Sprintf("Hello %v!\n", ua)
	c.String(http.StatusOK, message)
}