open System.Text.RegularExpressions

​

module SimpleNewsSite =

​

    // custom types    

    type Login = Login of string

    type Email = Email of string

    type Password = Password of string

    type Role = Administrator | Moderator | Journalist | User

    type Image = Image of string

    type DateTime = DateTime of string

    type Tag = Tag of string

    type String180 = String180 of string

    // objects

    type User = {

        login : Login

        email : Email

        password : Password

        role : Role

        avatar : Image option

        createdAt : DateTime

    }

    type Comment = {

        text : string

        author : User

        createdAt : DateTime

    }

    type Post = {

        title : String180

        shortText : string option

        fullText : string

        poster : Image

        tag : Tag list option

        views : int

        comments : Comment list

        author : User

        createdAt : DateTime

    }

    // validation

    let createLogin (s : string) = 

        if s.Length <= 50 && Regex.IsMatch(s, @"^[A-Za-z0-9]+$")

            then Some (Login s)

            else None

​

    let createEmail (s : string) = 

        if Regex.IsMatch(s, @"^\S+@\S+\.\S+$")

            then Some (Email s)

            else None

​

    let createPassword (s : string) = 

        if s.Length >= 8

            then Some (Password s)

            else None

​

    let createImage (s : string) = 

        if Regex.IsMatch(s.ToLower(), @"^*.(jpg|jpeg|png|bmp|gif)+$")

            then Some (Image s)

            else None

​

    let createDateTime (s : string) = 

        if s.Length = 19 && Regex.IsMatch(s, @"^([0-9]{2}).([0-9]{2}).([0-9]{4})[-. ]?([0-9]{2}):([0-9]{2}):([0-9]{2})+$")

            then Some (DateTime s)

            else None

​

    let createTag (s : string) = 

        if s.Length <= 20 && Regex.IsMatch(s, @"^[A-Za-zА-ЯЁа-яё0-9]+$")

            then Some (Tag s)

            else None

​

    let createString180 (s : string) = 

        if s.Length <= 180

            then Some (String180 s)

            else None