package settings

import (
	"crypto/rand"
	"encoding/json"
	"fmt"
	"log"
	"strings"
	"time"

	"github.com/filebrowser/filebrowser/v2/rules"
)

const DefaultUsersHomeBasePath = "/users"

// AuthMethod describes an authentication method.
type AuthMethod string

// Settings contain the main settings of the application.
type Settings struct {
	Key              []byte              `json:"key"`
	Signup           bool                `json:"signup"`
	CreateUserDir    bool                `json:"createUserDir"`
	UserHomeBasePath string              `json:"userHomeBasePath"`
	Defaults         UserDefaults        `json:"defaults"`
	AuthMethod       AuthMethod          `json:"authMethod"`
	Branding         Branding            `json:"branding"`
	Tus              Tus                 `json:"tus"`
	Commands         map[string][]string `json:"commands"`
	Shell            string              `json:"shell"`
	Rules            []rules.Rule        `json:"rules"`
}

// GetRules implements rules.Provider.
func (s *Settings) GetRules() []rules.Rule {
	return s.Rules
}

// Server specific settings.
type Server struct {
	Root                  string `json:"root"`
	BaseURL               string `json:"baseURL"`
	Socket                string `json:"socket"`
	TLSKey                string `json:"tlsKey"`
	TLSCert               string `json:"tlsCert"`
	Port                  string `json:"port"`
	Address               string `json:"address"`
	Log                   string `json:"log"`
	EnableThumbnails      bool   `json:"enableThumbnails"`
	ResizePreview         bool   `json:"resizePreview"`
	EnableExec            bool   `json:"enableExec"`
	TypeDetectionByHeader bool   `json:"typeDetectionByHeader"`
	AuthHook              string `json:"authHook"`
	TokenExpirationTime   string `json:"tokenExpirationTime"`
}

// Clean cleans any variables that might need cleaning.
func (s *Server) Clean() {
	s.BaseURL = strings.TrimSuffix(s.BaseURL, "/")
}

func (s *Server) GetTokenExpirationTime(fallback time.Duration) time.Duration {
	if s.TokenExpirationTime == "" {
		return fallback
	}

	duration, err := time.ParseDuration(s.TokenExpirationTime)
	if err != nil {
		log.Printf("[WARN] Failed to parse tokenExpirationTime: %v", err)
		return fallback
	}
	return duration
}

// GenerateKey generates a key of 512 bits.
func GenerateKey() ([]byte, error) {
	b := make([]byte, 64) //nolint:gomnd
	_, err := rand.Read(b)
	// Note that err == nil only if we read len(b) bytes.
	if err != nil {
		return nil, err
	}

	return b, nil
}

// UnmarshalJSON implements custom JSON unmarshaling for Settings
func (s *Settings) UnmarshalJSON(data []byte) error {

	type Alias Settings
	aux := &struct {
		Shell interface{} `json:"shell"`
		*Alias
	}{
		Alias: (*Alias)(s),
	}

	if err := json.Unmarshal(data, &aux); err != nil {
		return err
	}

	// Handle the Shell field conversion
	switch v := aux.Shell.(type) {
	case string:
		s.Shell = v
	case []interface{}:
		// Convert array to string by joining elements
		var parts []string
		for _, item := range v {
			if str, ok := item.(string); ok {
				parts = append(parts, str)
			}
		}
		s.Shell = strings.Join(parts, " ")
	case nil:
		s.Shell = ""
	default:
		return fmt.Errorf("invalid type for shell field: %T", v)
	}

	return nil
}