use super::*;
use cryptohelpers::sha256::Sha256Hash;

use hard_format::formats::{
    PEMFormattedString,
    PEMFormattedStr,
    MaxLenString,
};
use tripcode::Tripcode;

id_type!(PostID; "A unique post ID");

/// Max length of `email` or `name` feild
const ID_MAX_LEN: usize = defaults::POST_ID_MAX_LEN;

/// String type that limits its bytes to the ID string max limit.
pub type IDMaxString = MaxLenString<ID_MAX_LEN>;

/// The timestamp type used in posts
pub type PostTimestamp = chrono::DateTime<defaults::Timezone>;

/// A single completed post
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
pub struct Post
{
    /// Unique ID for each post
    id: PostID,
    
    name: Option<IDMaxString>,
    tripcode: Option<Tripcode>,
    email: Option<IDMaxString>,

    /// The client-side encrypted body string
    body: PEMFormattedString,
    /// Signature of the body (optional).
    signature: Option<PEMFormattedString>,

    /// Hash of the body
    hash: Sha256Hash,

    /// When the post was created
    created: PostTimestamp,
    /// When the post was last edited.
    ///
    /// # Notes
    /// Each new edit is pushed to the end of the vec, creation does not count as an edit.
    edited: Vec<PostTimestamp>,

    /// Optional dynamic expiry duration.
    expires_in: Option<tokio::time::Duration>,
}

impl Post
{
    /// Time since this post was created as a Chrono `Duration`.
    pub fn time_since_creation(&self) -> chrono::Duration
    {
	 defaults::Timezone::now() - self.created
    }
    /// Has this post expired?
    ///
    /// Expired posts should be removed
    pub fn expired(&self) -> bool
    {
	if let Ok(dur) = self.time_since_creation().to_std()
	{
	    dur >= *self.expires_in.as_ref().unwrap_or(&defaults::POST_EXPIRE)
	} else {
	    // Conversion failed. Expire the post
	    true
	}
    }
    /// The user-set name for this post if there is one.
    #[inline] pub fn own_name(&self) -> Option<&str>
    {
	self.name.as_ref().map(|x| x.as_str())
    }
    /// The name for this post.
    ///
    /// If no name is set, returns the default anon name.
    pub fn name(&self) -> &str
    {
	self.own_name().unwrap_or(defaults::ANON_NAME)
    }

    /// The email set for this post, if there is one.
    pub fn email(&self) -> Option<&str>
    {
	self.email.as_ref().map(|x| x.as_str())
    }

    /// Get the tripcode of this post, if there is one.
    pub fn tripcode(&self) -> Option<&Tripcode>
    {
	self.tripcode.as_ref()
    }
    
    /// The body of this post
    pub fn body(&self) -> &PEMFormattedStr
    {
	self.body.as_ref()
    }
}

#[cfg(test)]
mod tests
{
    #[test]
    fn post_serialise()
    {
	use std::convert::TryInto;
	let post = super::Post {
	    id: super::PostID::id_new(),
	    name: Some("Some name".to_owned().try_into().unwrap()),
	    email: None,
	    tripcode: Some(super::Tripcode::generate("uhh hello").unwrap()),
	    body: unsafe { super::PEMFormattedStr::new_unchecked("test").to_owned() }, //temporary
	    signature: None,
	    hash: Default::default(),

	    created: crate::defaults::Timezone::now(),
	    edited: Default::default(),
	    expires_in: None,
	};
	let post_json = serde_json::to_vec(&post).expect("Serialise");
	println!("Post json: {}", std::str::from_utf8(&post_json[..]).unwrap());
	let post2: super::Post = serde_json::from_slice(&post_json[..]).expect("Deserialise");
	assert_eq!(post, post2);
	println!("Post was: {:?}", post);
    }
}