package internal

import (
	"net/url"
	"regexp"
	"time"
)

const (
	// InvalidConfigValue is the constant value for invalid config values
	// which must be changed for production configurations before successful
	// startup
	InvalidConfigValue = "INVALID CONFIG VALUE - PLEASE CHANGE THIS VALUE"

	// DebugMode is the default debug mode
	DefaultDebug = false

	// DefaultData is the default data directory for storage
	DefaultData = "./data"

	// DefaultStore is the default data store used for accounts, sessions, etc
	DefaultStore = "bitcask://spyda.db"

	// DefaultBaseURL is the default Base URL for the app used to construct feed URLs
	DefaultBaseURL = "http://0.0.0.0:8000"

	// DefaultAdminXXX is the default admin user / pod operator
	DefaultAdminUser  = "admin"
	DefaultAdminPass  = "admiN"
	DefaultAdminName  = "Administrator"
	DefaultAdminEmail = "support@spyda.dev"

	// DefaultName is the default instance name
	DefaultName = "spyda.dev"

	// DefaultMetaxxx are the default set of <meta> tags used on non-specific views
	DefaultMetaTitle       = ""
	DefaultMetaAuthor      = "spyda.dev"
	DefaultMetaKeywords    = "spider, crawler, search, engine, web, index, spyda, find, lookup"
	DefaultMetaDescription = " 🕸 spyda is a privacy first search engine and web crawler."

	// DefaultTheme is the default theme to use ('light' or 'dark')
	DefaultTheme = "dark"

	// DefaultCookieSecret is the server's default cookie secret
	DefaultCookieSecret = InvalidConfigValue

	// DefaultResultsPerPage is the server's default results per page to display
	DefaultResultsPerPage = 10

	// DefaultSessionCacheTTL is the server's default session cache ttl
	DefaultSessionCacheTTL = 1 * time.Hour

	// DefaultSessionExpiry is the server's default session expiry time
	DefaultSessionExpiry = 240 * time.Hour // 10 days

	// DefaultMagicLinkSecret is the jwt magic link secret
	DefaultMagicLinkSecret = InvalidConfigValue

	// Default SMTP configuration
	DefaultSMTPHost = "smtp.gmail.com"
	DefaultSMTPPort = 587
	DefaultSMTPUser = InvalidConfigValue
	DefaultSMTPPass = InvalidConfigValue
	DefaultSMTPFrom = InvalidConfigValue

	// DefaultAPISessionTime is the server's default session time for API tokens
	DefaultAPISessionTime = 240 * time.Hour // 10 days

	// DefaultAPISigningKey is the default API JWT signing key for tokens
	DefaultAPISigningKey = InvalidConfigValue
)

var (
	// DefaultSearchPrompts are the set of default prompts for search(s)
	DefaultSearchPrompts = []string{
		`What can we find for you today?`,
		`Whatcha look'n for?`,
		`Looking for something? Type some keywords and hit Go!`,
		`Looking for a local buinsess? Find it here!`,
		`Tired of search engines tracking you? Search freely and privately here!`,
		`Search the web...`,
	}
)

func NewConfig() *Config {
	return &Config{
		Debug: DefaultDebug,

		Name:        DefaultName,
		Description: DefaultMetaDescription,
		Store:       DefaultStore,
		Theme:       DefaultTheme,
		BaseURL:     DefaultBaseURL,
		AdminUser:   DefaultAdminUser,
		AdminPass:   DefaultAdminPass,

		CookieSecret:    DefaultCookieSecret,
		MagicLinkSecret: DefaultMagicLinkSecret,

		SearchPrompts:  DefaultSearchPrompts,
		ResultsPerPage: DefaultResultsPerPage,

		SessionExpiry: DefaultSessionExpiry,

		SMTPHost: DefaultSMTPHost,
		SMTPPort: DefaultSMTPPort,
		SMTPUser: DefaultSMTPUser,
		SMTPPass: DefaultSMTPPass,
	}
}

// Option is a function that takes a config struct and modifies it
type Option func(*Config) error

// WithDebug sets the debug mode lfag
func WithDebug(debug bool) Option {
	return func(cfg *Config) error {
		cfg.Debug = debug
		return nil
	}
}

// WithData sets the data directory to use for storage
func WithData(data string) Option {
	return func(cfg *Config) error {
		cfg.Data = data
		return nil
	}
}

// WithStore sets the store to use for accounts, sessions, etc.
func WithStore(store string) Option {
	return func(cfg *Config) error {
		cfg.Store = store
		return nil
	}
}

// WithBaseURL sets the Base URL used for constructing feed URLs
func WithBaseURL(baseURL string) Option {
	return func(cfg *Config) error {
		u, err := url.Parse(baseURL)
		if err != nil {
			return err
		}
		cfg.BaseURL = baseURL
		cfg.baseURL = u
		return nil
	}
}

// WithAdminUser sets the Admin user used for granting special features to
func WithAdminUser(adminUser string) Option {
	return func(cfg *Config) error {
		cfg.AdminUser = adminUser
		return nil
	}
}

// WithAdminName sets the Admin name used to identify the pod operator
func WithAdminName(adminName string) Option {
	return func(cfg *Config) error {
		cfg.AdminName = adminName
		return nil
	}
}

// WithAdminEmail sets the Admin email used to contact the pod operator
func WithAdminEmail(adminEmail string) Option {
	return func(cfg *Config) error {
		cfg.AdminEmail = adminEmail
		return nil
	}
}

// WithFeedSources sets the feed sources  to use for external feeds
func WithFeedSources(feedSources []string) Option {
	return func(cfg *Config) error {
		cfg.FeedSources = feedSources
		return nil
	}
}

// WithName sets the instance's name
func WithName(name string) Option {
	return func(cfg *Config) error {
		cfg.Name = name
		return nil
	}
}

// WithDescription sets the instance's description
func WithDescription(description string) Option {
	return func(cfg *Config) error {
		cfg.Description = description
		return nil
	}
}

// WithTheme sets the default theme to use
func WithTheme(theme string) Option {
	return func(cfg *Config) error {
		cfg.Theme = theme
		return nil
	}
}

// WithOpenRegistrations sets the open registrations flag
func WithOpenRegistrations(openRegistrations bool) Option {
	return func(cfg *Config) error {
		cfg.OpenRegistrations = openRegistrations
		return nil
	}
}

// WithCookieSecret sets the server's cookie secret
func WithCookieSecret(secret string) Option {
	return func(cfg *Config) error {
		cfg.CookieSecret = secret
		return nil
	}
}

// WithResultsPerPage sets the server's results per page
func WithResultsPerPage(resultsPerPage int) Option {
	return func(cfg *Config) error {
		cfg.ResultsPerPage = resultsPerPage
		return nil
	}
}

// WithSessionCacheTTL sets the server's session cache ttl
func WithSessionCacheTTL(cacheTTL time.Duration) Option {
	return func(cfg *Config) error {
		cfg.SessionCacheTTL = cacheTTL
		return nil
	}
}

// WithSessionExpiry sets the server's session expiry time
func WithSessionExpiry(expiry time.Duration) Option {
	return func(cfg *Config) error {
		cfg.SessionExpiry = expiry
		return nil
	}
}

// WithTranscoderTimeout sets the video transcoding timeout
func WithTranscoderTimeout(timeout time.Duration) Option {
	return func(cfg *Config) error {
		cfg.TranscoderTimeout = timeout
		return nil
	}
}

// WithMagicLinkSecret sets the MagicLinkSecert used to create password reset tokens
func WithMagicLinkSecret(secret string) Option {
	return func(cfg *Config) error {
		cfg.MagicLinkSecret = secret
		return nil
	}
}

// WithSMTPBind sets the interface and port to bind to for SMTP
func WithSMTPBind(smtpBind string) Option {
	return func(cfg *Config) error {
		cfg.SMTPBind = smtpBind
		return nil
	}
}

// WithPOP3Bind sets the interface and port to use for POP3
func WithPOP3Bind(pop3Bind string) Option {
	return func(cfg *Config) error {
		cfg.POP3Bind = pop3Bind
		return nil
	}
}

// WithSMTPHost sets the SMTPHost to use for sending email
func WithSMTPHost(host string) Option {
	return func(cfg *Config) error {
		cfg.SMTPHost = host
		return nil
	}
}

// WithSMTPPort sets the SMTPPort to use for sending email
func WithSMTPPort(port int) Option {
	return func(cfg *Config) error {
		cfg.SMTPPort = port
		return nil
	}
}

// WithSMTPUser sets the SMTPUser to use for sending email
func WithSMTPUser(user string) Option {
	return func(cfg *Config) error {
		cfg.SMTPUser = user
		return nil
	}
}

// WithSMTPPass sets the SMTPPass to use for sending email
func WithSMTPPass(pass string) Option {
	return func(cfg *Config) error {
		cfg.SMTPPass = pass
		return nil
	}
}

// WithSMTPFrom sets the SMTPFrom address to use for sending email
func WithSMTPFrom(from string) Option {
	return func(cfg *Config) error {
		cfg.SMTPFrom = from
		return nil
	}
}

// WithMaxFetchLimit sets the maximum feed fetch limit in bytes
func WithMaxFetchLimit(limit int64) Option {
	return func(cfg *Config) error {
		cfg.MaxFetchLimit = limit
		return nil
	}
}

// WithAPISessionTime sets the API session time for tokens
func WithAPISessionTime(duration time.Duration) Option {
	return func(cfg *Config) error {
		cfg.APISessionTime = duration
		return nil
	}
}

// WithAPISigningKey sets the API JWT signing key for tokens
func WithAPISigningKey(key string) Option {
	return func(cfg *Config) error {
		cfg.APISigningKey = key
		return nil
	}
}

// WithWhitelistedDomains sets the list of domains whitelisted and permitted for external iamges
func WithWhitelistedDomains(whitelistedDomains []string) Option {
	return func(cfg *Config) error {
		for _, whitelistedDomain := range whitelistedDomains {
			re, err := regexp.Compile(whitelistedDomain)
			if err != nil {
				return err
			}
			cfg.whitelistedDomains = append(cfg.whitelistedDomains, re)
		}
		return nil
	}
}