package internal

import (
	"errors"
	"fmt"
	"io/ioutil"
	"math/rand"
	"net/url"
	"os"
	"regexp"
	"strings"
	"time"

	"github.com/gabstv/merger"
	"github.com/goccy/go-yaml"
	"git.mills.io/prologic/spyda/types"
	log "github.com/sirupsen/logrus"
)

var (
	ErrConfigPathMissing = errors.New("error: config file missing")
)

// Settings contains Pod Settings that can be customised via the Web UI
type Settings struct {
	Name        string `yaml:"pod_name"`
	Description string `yaml:"pod_description"`

	MaxTwtLength int `yaml:"max_twt_length"`

	OpenProfiles      bool `yaml:"open_profiles"`
	OpenRegistrations bool `yaml:"open_registrations"`
}

// Config contains the server configuration parameters
type Config struct {
	Debug bool

	Data              string
	Name              string
	Description       string
	Store             string
	Theme             string
	BaseURL           string
	AdminUser         string
	AdminName         string
	AdminEmail        string
	FeedSources       []string
	RegisterMessage   string
	CookieSecret      string
	TwtPrompts        []string
	TwtsPerPage       int
	MaxUploadSize     int64
	MaxTwtLength      int
	MaxCacheTTL       time.Duration
	MaxCacheItems     int
	MsgsPerPage       int
	OpenProfiles      bool
	OpenRegistrations bool
	SessionExpiry     time.Duration
	SessionCacheTTL   time.Duration
	TranscoderTimeout time.Duration

	MagicLinkSecret string

	SMTPBind string
	POP3Bind string

	SMTPHost string
	SMTPPort int
	SMTPUser string
	SMTPPass string
	SMTPFrom string

	MaxFetchLimit int64

	APISessionTime time.Duration
	APISigningKey  string

	baseURL *url.URL

	whitelistedDomains []*regexp.Regexp
	WhitelistedDomains []string

	// path string
}

var _ types.FmtOpts = (*Config)(nil)

func (c *Config) IsLocalURL(url string) bool {
	if NormalizeURL(url) == "" {
		return false
	}
	return strings.HasPrefix(NormalizeURL(url), NormalizeURL(c.BaseURL))
}
func (c *Config) LocalURL() *url.URL                  { return c.baseURL }
func (c *Config) ExternalURL(nick, uri string) string { return URLForExternalProfile(c, nick, uri) }
func (c *Config) UserURL(url string) string           { return UserURL(url) }

// Settings returns a `Settings` struct containing pod settings that can
// then be persisted to disk to override some configuration options.
func (c *Config) Settings() *Settings {
	settings := &Settings{}

	if err := merger.MergeOverwrite(settings, c); err != nil {
		log.WithError(err).Warn("error creating pod settings")
	}

	return settings
}

// WhitelistedDomain returns true if the domain provided is a whiltelisted
// domain as per the configuration
func (c *Config) WhitelistedDomain(domain string) (bool, bool) {
	// Always per mit our own domain
	ourDomain := strings.TrimPrefix(strings.ToLower(c.baseURL.Hostname()), "www.")
	if domain == ourDomain {
		return true, true
	}

	// Check against list of whitelistedDomains (regexes)
	for _, re := range c.whitelistedDomains {
		if re.MatchString(domain) {
			return true, false
		}
	}
	return false, false
}

// RandomTwtPrompt returns a random  Twt Prompt for display by the UI
func (c *Config) RandomTwtPrompt() string {
	n := rand.Int() % len(c.TwtPrompts)
	return c.TwtPrompts[n]
}

// Validate validates the configuration is valid which for the most part
// just ensures that default secrets are actually configured correctly
func (c *Config) Validate() error {
	if c.Debug {
		return nil
	}

	if c.CookieSecret == InvalidConfigValue {
		return fmt.Errorf("error: COOKIE_SECRET is not configured!")
	}

	if c.MagicLinkSecret == InvalidConfigValue {
		return fmt.Errorf("error: MAGICLINK_SECRET is not configured!")
	}

	if c.APISigningKey == InvalidConfigValue {
		return fmt.Errorf("error: API_SIGNING_KEY is not configured!")
	}

	return nil
}

// LoadSettings loads pod settings from the given path
func LoadSettings(path string) (*Settings, error) {
	var settings Settings

	data, err := ioutil.ReadFile(path)
	if err != nil {
		return nil, err
	}

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

	return &settings, nil
}

// Save saves the pod settings to the given path
func (s *Settings) Save(path string) error {
	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
	if err != nil {
		return err
	}

	data, err := yaml.MarshalWithOptions(s, yaml.Indent(4))
	if err != nil {
		return err
	}

	if _, err = f.Write(data); err != nil {
		return err
	}

	if err = f.Sync(); err != nil {
		return err
	}

	return f.Close()
}