package mongo

import (
	"fmt"
	"net/url"
	"strings"
)

const connectionScheme = `mongodb`

// ConnectionURL implements a MongoDB connection struct.
type ConnectionURL struct {
	User     string
	Password string
	Host     string
	Database string
	Options  map[string]string
}

func (c ConnectionURL) String() (s string) {

	if c.Database == "" {
		return ""
	}

	vv := url.Values{}

	// Do we have any options?
	if c.Options == nil {
		c.Options = map[string]string{}
	}

	// Converting options into URL values.
	for k, v := range c.Options {
		vv.Set(k, v)
	}

	// Has user?
	var userInfo *url.Userinfo

	if c.User != "" {
		if c.Password == "" {
			userInfo = url.User(c.User)
		} else {
			userInfo = url.UserPassword(c.User, c.Password)
		}
	}

	// Building URL.
	u := url.URL{
		Scheme:   connectionScheme,
		Path:     c.Database,
		Host:     c.Host,
		User:     userInfo,
		RawQuery: vv.Encode(),
	}

	return u.String()
}

// ParseURL parses s into a ConnectionURL struct.
func ParseURL(s string) (conn ConnectionURL, err error) {
	var u *url.URL

	if !strings.HasPrefix(s, connectionScheme+"://") {
		return conn, fmt.Errorf(`Expecting mongodb:// connection scheme.`)
	}

	if u, err = url.Parse(s); err != nil {
		return conn, err
	}

	conn.Host = u.Host

	// Deleting / from start of the string.
	conn.Database = strings.Trim(u.Path, "/")

	// Adding user / password.
	if u.User != nil {
		conn.User = u.User.Username()
		conn.Password, _ = u.User.Password()
	}

	// Adding options.
	conn.Options = map[string]string{}

	var vv url.Values

	if vv, err = url.ParseQuery(u.RawQuery); err != nil {
		return conn, err
	}

	for k := range vv {
		conn.Options[k] = vv.Get(k)
	}

	return conn, err
}