use crate::{
    comment_seers::{CommentSeers, NewCommentSeers},
    db_conn::DbConn,
    instance::Instance,
    medias::Media,
    mentions::Mention,
    notifications::*,
    posts::Post,
    safe_string::SafeString,
    schema::comments,
    users::User,
    Connection, Error, Result, CONFIG,
};
use activitypub::{
    activity::{Create, Delete},
    link,
    object::{Note, Tombstone},
};
use chrono::{self, NaiveDateTime};
use diesel::{self, ExpressionMethods, QueryDsl, RunQueryDsl, SaveChangesDsl};
use plume_common::{
    activity_pub::{
        inbox::{AsActor, AsObject, FromId},
        sign::Signer,
        Id, IntoId, PUBLIC_VISIBILITY,
    },
    utils,
};
use std::collections::HashSet;

#[derive(Queryable, Identifiable, Clone, AsChangeset)]
pub struct Comment {
    pub id: i32,
    pub content: SafeString,
    pub in_response_to_id: Option<i32>,
    pub post_id: i32,
    pub author_id: i32,
    pub creation_date: NaiveDateTime,
    pub ap_url: Option<String>,
    pub sensitive: bool,
    pub spoiler_text: String,
    pub public_visibility: bool,
}

#[derive(Insertable, Default)]
#[table_name = "comments"]
pub struct NewComment {
    pub content: SafeString,
    pub in_response_to_id: Option<i32>,
    pub post_id: i32,
    pub author_id: i32,
    pub ap_url: Option<String>,
    pub sensitive: bool,
    pub spoiler_text: String,
    pub public_visibility: bool,
}

impl Comment {
    insert!(comments, NewComment, |inserted, conn| {
        if inserted.ap_url.is_none() {
            inserted.ap_url = Some(format!(
                "{}comment/{}",
                inserted.get_post(conn)?.ap_url,
                inserted.id
            ));
            let _: Comment = inserted.save_changes(conn)?;
        }
        Ok(inserted)
    });
    get!(comments);
    list_by!(comments, list_by_post, post_id as i32);
    find_by!(comments, find_by_ap_url, ap_url as &str);

    pub fn get_author(&self, conn: &Connection) -> Result<User> {
        User::get(conn, self.author_id)
    }

    pub fn get_post(&self, conn: &Connection) -> Result<Post> {
        Post::get(conn, self.post_id)
    }

    pub fn count_local(conn: &Connection) -> Result<i64> {
        use crate::schema::users;
        let local_authors = users::table
            .filter(users::instance_id.eq(Instance::get_local()?.id))
            .select(users::id);
        comments::table
            .filter(comments::author_id.eq_any(local_authors))
            .count()
            .get_result(conn)
            .map_err(Error::from)
    }

    pub fn get_responses(&self, conn: &Connection) -> Result<Vec<Comment>> {
        comments::table
            .filter(comments::in_response_to_id.eq(self.id))
            .load::<Comment>(conn)
            .map_err(Error::from)
    }

    pub fn can_see(&self, conn: &Connection, user: Option<&User>) -> bool {
        self.public_visibility
            || user
                .as_ref()
                .map(|u| CommentSeers::can_see(conn, self, u).unwrap_or(false))
                .unwrap_or(false)
    }

    pub fn to_activity(&self, conn: &DbConn) -> Result<Note> {
        let author = User::get(conn, self.author_id)?;
        let (html, mentions, _hashtags) = utils::md_to_html(
            self.content.get().as_ref(),
            Some(&Instance::get_local()?.public_domain),
            true,
            Some(Media::get_media_processor(conn, vec![&author])),
        );

        let mut note = Note::default();
        let to = vec![Id::new(PUBLIC_VISIBILITY.to_string())];

        note.object_props
            .set_id_string(self.ap_url.clone().unwrap_or_default())?;
        note.object_props
            .set_summary_string(self.spoiler_text.clone())?;
        note.object_props.set_content_string(html)?;
        note.object_props
            .set_in_reply_to_link(Id::new(self.in_response_to_id.map_or_else(
                || Ok(Post::get(conn, self.post_id)?.ap_url),
                |id| Ok(Comment::get(conn, id)?.ap_url.unwrap_or_default()) as Result<String>,
            )?))?;
        note.object_props
            .set_published_string(chrono::Utc::now().to_rfc3339())?;
        note.object_props.set_attributed_to_link(author.into_id())?;
        note.object_props.set_to_link_vec(to)?;
        note.object_props.set_tag_link_vec(
            mentions
                .into_iter()
                .filter_map(|m| Mention::build_activity(conn, &m).ok())
                .collect::<Vec<link::Mention>>(),
        )?;
        Ok(note)
    }

    pub fn create_activity(&self, conn: &DbConn) -> Result<Create> {
        let author = User::get(conn, self.author_id)?;

        let note = self.to_activity(conn)?;
        let mut act = Create::default();
        act.create_props.set_actor_link(author.into_id())?;
        act.create_props.set_object_object(note.clone())?;
        act.object_props.set_id_string(format!(
            "{}/activity",
            self.ap_url.clone().ok_or(Error::MissingApProperty)?,
        ))?;
        act.object_props
            .set_to_link_vec(note.object_props.to_link_vec::<Id>()?)?;
        act.object_props
            .set_cc_link_vec(vec![Id::new(self.get_author(conn)?.followers_endpoint)])?;
        Ok(act)
    }

    pub fn notify(&self, conn: &Connection) -> Result<()> {
        for author in self.get_post(conn)?.get_authors(conn)? {
            if Mention::list_for_comment(conn, self.id)?
                .iter()
                .all(|m| m.get_mentioned(conn).map(|u| u != author).unwrap_or(true))
                && author.is_local()
            {
                Notification::insert(
                    conn,
                    NewNotification {
                        kind: notification_kind::COMMENT.to_string(),
                        object_id: self.id,
                        user_id: author.id,
                    },
                )?;
            }
        }
        Ok(())
    }

    pub fn build_delete(&self, conn: &Connection) -> Result<Delete> {
        let mut act = Delete::default();
        act.delete_props
            .set_actor_link(self.get_author(conn)?.into_id())?;

        let mut tombstone = Tombstone::default();
        tombstone
            .object_props
            .set_id_string(self.ap_url.clone().ok_or(Error::MissingApProperty)?)?;
        act.delete_props.set_object_object(tombstone)?;

        act.object_props
            .set_id_string(format!("{}#delete", self.ap_url.clone().unwrap()))?;
        act.object_props
            .set_to_link_vec(vec![Id::new(PUBLIC_VISIBILITY)])?;

        Ok(act)
    }
}

impl FromId<DbConn> for Comment {
    type Error = Error;
    type Object = Note;

    fn from_db(conn: &DbConn, id: &str) -> Result<Self> {
        Self::find_by_ap_url(conn, id)
    }

    fn from_activity(conn: &DbConn, note: Note) -> Result<Self> {
        let comm = {
            let previous_url = note
                .object_props
                .in_reply_to
                .as_ref()
                .ok_or(Error::MissingApProperty)?
                .as_str()
                .ok_or(Error::MissingApProperty)?;
            let previous_comment = Comment::find_by_ap_url(conn, previous_url);

            let is_public = |v: &Option<serde_json::Value>| match v
                .as_ref()
                .unwrap_or(&serde_json::Value::Null)
            {
                serde_json::Value::Array(v) => v
                    .iter()
                    .filter_map(serde_json::Value::as_str)
                    .any(|s| s == PUBLIC_VISIBILITY),
                serde_json::Value::String(s) => s == PUBLIC_VISIBILITY,
                _ => false,
            };

            let public_visibility = is_public(&note.object_props.to)
                || is_public(&note.object_props.bto)
                || is_public(&note.object_props.cc)
                || is_public(&note.object_props.bcc);

            let comm = Comment::insert(
                conn,
                NewComment {
                    content: SafeString::new(&note.object_props.content_string()?),
                    spoiler_text: note.object_props.summary_string().unwrap_or_default(),
                    ap_url: note.object_props.id_string().ok(),
                    in_response_to_id: previous_comment.iter().map(|c| c.id).next(),
                    post_id: previous_comment.map(|c| c.post_id).or_else(|_| {
                        Ok(Post::find_by_ap_url(conn, previous_url)?.id) as Result<i32>
                    })?,
                    author_id: User::from_id(
                        conn,
                        &note.object_props.attributed_to_link::<Id>()?,
                        None,
                        CONFIG.proxy(),
                    )
                    .map_err(|(_, e)| e)?
                    .id,
                    sensitive: note.object_props.summary_string().is_ok(),
                    public_visibility,
                },
            )?;

            // save mentions
            if let Some(serde_json::Value::Array(tags)) = note.object_props.tag.clone() {
                for tag in tags {
                    serde_json::from_value::<link::Mention>(tag)
                        .map_err(Error::from)
                        .and_then(|m| {
                            let author = &Post::get(conn, comm.post_id)?.get_authors(conn)?[0];
                            let not_author = m.link_props.href_string()? != author.ap_url.clone();
                            Mention::from_activity(conn, &m, comm.id, false, not_author)
                        })
                        .ok();
                }
            }
            comm
        };

        if !comm.public_visibility {
            let receivers_ap_url = |v: Option<serde_json::Value>| {
                let filter = |e: serde_json::Value| {
                    if let serde_json::Value::String(s) = e {
                        Some(s)
                    } else {
                        None
                    }
                };
                match v.unwrap_or(serde_json::Value::Null) {
                    serde_json::Value::Array(v) => v,
                    v => vec![v],
                }
                .into_iter()
                .filter_map(filter)
            };

            let mut note = note;

            let to = receivers_ap_url(note.object_props.to.take());
            let cc = receivers_ap_url(note.object_props.cc.take());
            let bto = receivers_ap_url(note.object_props.bto.take());
            let bcc = receivers_ap_url(note.object_props.bcc.take());

            let receivers_ap_url = to
                .chain(cc)
                .chain(bto)
                .chain(bcc)
                .collect::<HashSet<_>>() // remove duplicates (don't do a query more than once)
                .into_iter()
                .flat_map(|v| {
                    if let Ok(user) = User::from_id(conn, &v, None, CONFIG.proxy()) {
                        vec![user]
                    } else {
                        vec![] // TODO try to fetch collection
                    }
                })
                .filter(|u| u.get_instance(conn).map(|i| i.local).unwrap_or(false))
                .collect::<HashSet<User>>(); //remove duplicates (prevent db error)

            for user in &receivers_ap_url {
                CommentSeers::insert(
                    conn,
                    NewCommentSeers {
                        comment_id: comm.id,
                        user_id: user.id,
                    },
                )?;
            }
        }

        comm.notify(conn)?;
        Ok(comm)
    }

    fn get_sender() -> &'static dyn Signer {
        Instance::get_local_instance_user().expect("Failed to local instance user")
    }
}

impl AsObject<User, Create, &DbConn> for Comment {
    type Error = Error;
    type Output = Self;

    fn activity(self, _conn: &DbConn, _actor: User, _id: &str) -> Result<Self> {
        // The actual creation takes place in the FromId impl
        Ok(self)
    }
}

impl AsObject<User, Delete, &DbConn> for Comment {
    type Error = Error;
    type Output = ();

    fn activity(self, conn: &DbConn, actor: User, _id: &str) -> Result<()> {
        if self.author_id != actor.id {
            return Err(Error::Unauthorized);
        }

        for m in Mention::list_for_comment(conn, self.id)? {
            for n in Notification::find_for_mention(conn, &m)? {
                n.delete(conn)?;
            }
            m.delete(conn)?;
        }

        for n in Notification::find_for_comment(conn, &self)? {
            n.delete(&**conn)?;
        }

        diesel::update(comments::table)
            .filter(comments::in_response_to_id.eq(self.id))
            .set(comments::in_response_to_id.eq(self.in_response_to_id))
            .execute(&**conn)?;
        diesel::delete(&self).execute(&**conn)?;
        Ok(())
    }
}

pub struct CommentTree {
    pub comment: Comment,
    pub responses: Vec<CommentTree>,
}

impl CommentTree {
    pub fn from_post(conn: &Connection, p: &Post, user: Option<&User>) -> Result<Vec<Self>> {
        Ok(Comment::list_by_post(conn, p.id)?
            .into_iter()
            .filter(|c| c.in_response_to_id.is_none())
            .filter(|c| c.can_see(conn, user))
            .filter_map(|c| Self::from_comment(conn, c, user).ok())
            .collect())
    }

    pub fn from_comment(conn: &Connection, comment: Comment, user: Option<&User>) -> Result<Self> {
        let responses = comment
            .get_responses(conn)?
            .into_iter()
            .filter(|c| c.can_see(conn, user))
            .filter_map(|c| Self::from_comment(conn, c, user).ok())
            .collect();
        Ok(CommentTree { comment, responses })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::inbox::{inbox, tests::fill_database, InboxResult};
    use crate::safe_string::SafeString;
    use crate::tests::db;
    use diesel::Connection;

    // creates a post, get it's Create activity, delete the post,
    // "send" the Create to the inbox, and check it works
    #[test]
    fn self_federation() {
        let conn = &db();
        conn.test_transaction::<_, (), _>(|| {
            let (posts, users, _) = fill_database(&conn);

            let original_comm = Comment::insert(
                conn,
                NewComment {
                    content: SafeString::new("My comment"),
                    in_response_to_id: None,
                    post_id: posts[0].id,
                    author_id: users[0].id,
                    ap_url: None,
                    sensitive: true,
                    spoiler_text: "My CW".into(),
                    public_visibility: true,
                },
            )
            .unwrap();
            let act = original_comm.create_activity(&conn).unwrap();
            inbox(
                &conn,
                serde_json::to_value(original_comm.build_delete(&conn).unwrap()).unwrap(),
            )
            .unwrap();

            match inbox(&conn, serde_json::to_value(act).unwrap()).unwrap() {
                InboxResult::Commented(c) => {
                    // TODO: one is HTML, the other markdown: assert_eq!(c.content, original_comm.content);
                    assert_eq!(c.in_response_to_id, original_comm.in_response_to_id);
                    assert_eq!(c.post_id, original_comm.post_id);
                    assert_eq!(c.author_id, original_comm.author_id);
                    assert_eq!(c.ap_url, original_comm.ap_url);
                    assert_eq!(c.spoiler_text, original_comm.spoiler_text);
                    assert_eq!(c.public_visibility, original_comm.public_visibility);
                }
                _ => panic!("Unexpected result"),
            };
            Ok(())
        })
    }
}
