package internal

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

	"github.com/gabstv/merger"
	"github.com/goccy/go-yaml"
	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"`
}

// 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
	AdminPass   string
	AdminName   string
	AdminEmail  string

	SearchPrompts  []string
	ResultsPerPage int

	APISessionTime  time.Duration
	SessionExpiry   time.Duration
	SessionCacheTTL time.Duration

	APISigningKey   string
	CookieSecret    string
	MagicLinkSecret string

	SMTPHost string
	SMTPPort int
	SMTPUser string
	SMTPPass string
	SMTPFrom string

	baseURL *url.URL
}

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 }

// 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
}

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