package config

import (
	"bufio"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net"
	"os"
	"path"

	"golang.org/x/crypto/bcrypt"
)

var (
	// File to store the app configuration, like username, password, token, repo dir, logging level
	ConfigFilePath string

	// Repo dir
	NpmRepoDir string

	// HTTPListen
	HTTPListen string

	// Set Verbose Logging
	CanLog bool

	// Logging Level
	LoggingLvl string

	// Username
	RegUser string

	// Password
	RegPwd string
)

type Config struct {
	Token     string `json:"token"`
	RepoDir   string `json:"repoDir"`
	IpAddress string `json:"ipAddress"`
	LogLevel  string `json:"logLevel"`
}

func checkIfCorrectIPPort(s string) bool {
	host, port, _ := net.SplitHostPort(s)
	if host == "" || port == "" {
		return false
	}
	if net.ParseIP(host) != nil {
		return true
	}
	_, err := net.ResolveIPAddr("ip", host)
	return err == nil
}

func VerifyConfig() error {
	if !checkIfCorrectIPPort(HTTPListen) {
		return errors.New("ip address should be in the format of <ip>:<port>")
	}

	// Check if config file exists
	dirname, err := os.UserHomeDir()
	if err != nil {
		return err
	}
	configDirPath, err := checkOrCreateConfigDir(dirname, true)
	if err != nil {
		return err
	}

	ConfigFilePath = path.Join(configDirPath, "config.json")

	if NpmRepoDir == "" {
		NpmRepoDir = path.Join(dirname, ".gosimplenpm", "registry")
		err := checkOrCreateRepoDir(NpmRepoDir)
		if err != nil {
			return err
		}
	} else if NpmRepoDir != "" {
		err := checkOrCreateRepoDir(NpmRepoDir)
		if err != nil {
			return err
		}
	}

	if CanLog {
		LoggingLvl = "DEBUG"
		fmt.Println("\n Enabled debug logging")
	} else {
		LoggingLvl = "INFO"
	}

	return nil
}

func checkOrCreateConfigDir(fp string, canCreate bool) (string, error) {
	configDirPath := path.Join(fp, ".gosimplenpm", "config")
	ok := isDir(configDirPath)
	if !ok && canCreate {
		err := os.MkdirAll(configDirPath, os.ModePerm)
		if err != nil {
			return "", err
		}
	}
	if !ok && !canCreate {
		return "", nil
	}
	return configDirPath, nil
}

func checkOrCreateRepoDir(repoDirPath string) error {
	ok := isDir(repoDirPath)
	if !ok {
		err := os.MkdirAll(repoDirPath, os.ModePerm)
		if err != nil {
			return err
		}
	}
	return nil
}

func createConfig(cfg *Config, recreate bool) error {
	var scanner *bufio.Scanner
	if recreate {
		fmt.Println("\nNew config variables. Saving...")
	} else {
		fmt.Println("\nConfig file is not found. Creating...")
	}

	configFile, err := os.Create(ConfigFilePath)
	if err != nil {
		return err
	}

	defer configFile.Close()

	cfg.IpAddress = HTTPListen
	cfg.LogLevel = LoggingLvl

	// Get username
	if cfg.Token == "" {
		fmt.Println("Enter your username: ")
		scanner = bufio.NewScanner(os.Stdin)
		scanner.Scan()
		err = scanner.Err()
		if err != nil {
			return err
		}
		RegUser = scanner.Text()

		fmt.Println("Enter your password: ")
		scanner = bufio.NewScanner(os.Stdin)
		scanner.Scan()
		err = scanner.Err()
		if err != nil {
			return err
		}
		RegPwd = scanner.Text()

		token, err := generateAuthToken()
		if err != nil {
			return err
		}

		cfg.Token = token
	}

	fmt.Printf("The npm authToken is %s.\n", cfg.Token)

	err = json.NewEncoder(configFile).Encode(cfg)
	if err != nil {
		return err
	}

	return nil
}

func loadConfig(cfg *Config) error {
	configFile, err := os.Open(ConfigFilePath)
	if err != nil {
		return err
	}

	defer configFile.Close()

	err = json.NewDecoder(configFile).Decode(cfg)
	if err != nil {
		return err
	}

	return nil
}

func LoadOrCreateConfig(cfg *Config) error {
	var err error
	ok := isFile(ConfigFilePath)

	// If file is not found
	if !ok {
		err = createConfig(cfg, false)
		if err != nil {
			return err
		}
	}

	if ok {
		// File is found
		err = loadConfig(cfg)
		if err != nil {
			return err
		}

		if cfg.Token == "" || cfg.IpAddress != HTTPListen || cfg.LogLevel != LoggingLvl || cfg.RepoDir != NpmRepoDir {
			// recreate the config file
			err = createConfig(cfg, true)
			if err != nil {
				return err
			}
		}
	}

	return err
}

func isFile(fp string) bool {
	info, err := os.Stat(fp)
	if os.IsNotExist(err) || !info.Mode().IsRegular() {
		return false
	}
	return true
}

func isDir(fp string) bool {
	info, err := os.Stat(fp)
	if os.IsNotExist(err) || !info.IsDir() {
		return false
	}
	return true
}

// Hash password
func hashPassword(password string) (string, error) {

	// Convert password string to byte slice
	var passwordBytes = []byte(password)
	// Hash password with Bcrypt's min cost
	hashedPasswordBytes, err := bcrypt.GenerateFromPassword(passwordBytes, bcrypt.MinCost)
	return string(hashedPasswordBytes), err
}

// Check if two passwords match using Bcrypt's CompareHashAndPassword
// which return nil on success and an error on failure.
// func doPasswordsMatch(hashedPassword, currPassword string) bool {
// 	err := bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(currPassword))
// 	return err == nil
// }

func generateAuthToken() (string, error) {
	hashed, err := hashPassword(RegPwd)
	if err != nil {
		return "", err
	}
	token := fmt.Sprintf("%s::%s", RegUser, hashed)
	return token, nil
}

func PrintConfigFile() error {
	// Check if config file exists
	dirname, err := os.UserHomeDir()
	if err != nil {
		return err
	}
	configDirPath, err := checkOrCreateConfigDir(dirname, false)
	if err != nil {
		return err
	}

	if configDirPath == "" {
		return errors.New("config dir is not found")
	}

	ConfigFilePath = path.Join(configDirPath, "config.json")
	ok := isFile(ConfigFilePath)
	if !ok {
		return errors.New("config file is not found")
	}

	configFile, err := os.Open(ConfigFilePath)
	if err != nil {
		return err
	}

	defer configFile.Close()

	b, err := io.ReadAll(configFile)
	if err != nil {
		return err
	}
	var result map[string]interface{}
	err = json.Unmarshal([]byte(b), &result)
	if err != nil {
		return err
	}

	// Pretty-print the result
	marshaled, err := json.MarshalIndent(result, "", " ")
	if err != nil {
		return err
	}

	fmt.Printf("Printing config located at %s: \n %s\n", ConfigFilePath, (marshaled))

	return nil
}