//! # Posts helper
//!
//! @author Pierre Hubert



use crate::constants::database_tables_names::POSTS_TABLE;
use crate::data::error::{ExecError, ResultBoxError};
use crate::data::group_id::GroupID;
use crate::data::group_member::GroupMembershipLevel;
use crate::data::movie::Movie;
use crate::data::post::{Post, PostAccessLevel, PostFile, PostKind, PostPageKind, PostVisibilityLevel, PostWebLink};
use crate::data::post::PostKind::{POST_KIND_COUNTDOWN, POST_KIND_IMAGE, POST_KIND_MOVIE, POST_KIND_PDF, POST_KIND_SURVEY, POST_KIND_WEBLINK, POST_KIND_YOUTUBE};
use crate::data::user::UserID;
use crate::helpers::{comments_helper, database, friends_helper, groups_helper, likes_helper, survey_helper, user_helper};
use crate::helpers::likes_helper::LikeType;
use crate::utils::date_utils::{mysql_date, time};
use crate::utils::user_data_utils::user_data_path;

impl PostVisibilityLevel {
    pub fn to_db(&self) -> u32 {
        match self {
            PostVisibilityLevel::VISIBILITY_PUBLIC => 1,
            PostVisibilityLevel::VISIBILITY_FRIENDS => 2,
            PostVisibilityLevel::VISIBILITY_USER => 3,
            PostVisibilityLevel::VISIBILITY_GROUP_MEMBERS => 50,
        }
    }

    pub fn from_db(val: u32) -> PostVisibilityLevel {
        match val {
            1 => PostVisibilityLevel::VISIBILITY_PUBLIC,
            2 => PostVisibilityLevel::VISIBILITY_FRIENDS,
            3 => PostVisibilityLevel::VISIBILITY_USER,
            50 => PostVisibilityLevel::VISIBILITY_GROUP_MEMBERS,
            _ => PostVisibilityLevel::VISIBILITY_PUBLIC,
        }
    }
}

impl PostKind {
    pub fn to_db(&self) -> String {
        match self {
            PostKind::POST_KIND_TEXT => "texte",
            POST_KIND_IMAGE(_) => "image",
            POST_KIND_WEBLINK(_) => "webpage_link",
            POST_KIND_PDF(_) => "pdf",
            POST_KIND_MOVIE(_) => "video",
            POST_KIND_COUNTDOWN(_) => "count_down",
            POST_KIND_SURVEY => "sondage",
            POST_KIND_YOUTUBE(_) => "youtube",
        }.to_string()
    }
}

/// Create a new post
pub fn create(p: &Post) -> ResultBoxError<u64> {

    // Determine post target
    let (user_id, friend_id, group_id) = match &p.target_page {
        PostPageKind::PAGE_KIND_USER(user_id) => {
            (user_id, Some(&p.user_id), None)
        }
        PostPageKind::PAGE_KIND_GROUP(group_id) => {
            (&p.user_id, None, Some(group_id))
        }
    };

    // Start insert query
    let mut insert_query = database::InsertQuery::new(POSTS_TABLE)
        .add_user_id("ID_personne", user_id)
        .add_u64("ID_amis", friend_id.map(|f| f.id()).unwrap_or(0))
        .add_u64("group_id", group_id.map(|f| f.id()).unwrap_or(0))
        .add_str("date_envoi", &mysql_date())
        .add_u64("time_insert", p.time_create)
        .add_u32("niveau_visibilite", p.visibility.to_db())
        .add_str("type", &p.kind.to_db())
        .add_opt_str("texte", p.content.as_ref());

    match &p.kind {
        PostKind::POST_KIND_TEXT => { /* nothing to do */ }

        // Posts with associated file
        POST_KIND_IMAGE(file) | POST_KIND_PDF(file) => {
            insert_query = insert_query.add_str("path", &file.path)
                .add_usize("size", file.size)
                .add_opt_str("file_type", file.file_type.as_ref());
        }

        // YouTube posts
        POST_KIND_YOUTUBE(id) => {
            insert_query = insert_query.add_str("path", id)
                .add_str("type", "youtube");
        }

        // Movie post
        POST_KIND_MOVIE(id) => {
            insert_query = insert_query.add_u64("idvideo", *id);
        }

        // Weblink
        POST_KIND_WEBLINK(weblink) => {
            insert_query = insert_query
                .add_str("url_page", &weblink.url)
                .add_opt_str("titre_page", weblink.title.as_ref())
                .add_opt_str("description_page", weblink.description.as_ref())
                .add_opt_str("image_page", weblink.image.as_ref());
        }

        // Countdown timer
        POST_KIND_COUNTDOWN(count_down) => {
            insert_query = insert_query.add_u64("time_end", *count_down);
        }

        // Survey
        POST_KIND_SURVEY => { /* Nothing to be done */ }
    }

    // Execute insertion
    let post_id = insert_query.insert()?
        .ok_or(ExecError::new("Insert post query did not return a result!"))?;

    Ok(post_id)
}


pub struct PostsQuery {
    /// The ID of the user making the request
    user_id: Option<UserID>,

    /// Maximum number of posts to get
    limit: u64,

    /// Starting post
    start_from: u64,
}

impl PostsQuery {
    /// Construct a new request
    pub fn new(user_id: Option<UserID>) -> PostsQuery {
        PostsQuery {
            user_id,
            limit: 10,
            start_from: 0,
        }
    }

    /// Start starting point
    pub fn set_start_from(mut self, start_from: u64) -> PostsQuery {
        self.start_from = start_from;
        self
    }

    /// Set the limit for this query
    pub fn set_limit(mut self, limit: u64) -> PostsQuery {
        self.limit = limit;
        self
    }

    /// Get the posts of a user
    pub fn get_user(self, user_id: &UserID) -> ResultBoxError<Vec<Post>> {
        get_user(&self, user_id)
    }

    /// Get the posts of a group
    pub fn get_group(self, group_id: &GroupID) -> ResultBoxError<Vec<Post>> {
        get_group(&self, group_id)
    }

    /// Get the latest posts for a user
    pub fn get_latest(self, include_groups_posts: bool) -> ResultBoxError<Vec<Post>> {
        get_latest(&self, include_groups_posts)
    }
}

/// Get the posts of `target_id`
fn get_user(query: &PostsQuery, target_id: &UserID) -> ResultBoxError<Vec<Post>> {
    // Max user visibility
    let mut level = PostVisibilityLevel::VISIBILITY_PUBLIC;

    if let Some(user_id) = &query.user_id {
        if user_id == target_id {
            level = PostVisibilityLevel::VISIBILITY_USER;
        } else if friends_helper::are_friend(user_id, target_id)? {
            level = PostVisibilityLevel::VISIBILITY_FRIENDS;
        }
    }

    // Start request
    let mut db_query = database::QueryInfo::new(POSTS_TABLE);
    let mut custom_where = String::new();

    // Preprocess conditions

    // ============= PERMISSION CONDITIONS =================
    custom_where.push_str("((niveau_visibilite <= ?) ");
    db_query = db_query.add_custom_where_argument_u32(level.to_db());

    // Add user posts (if signed in)
    if let Some(user_id) = &query.user_id {
        custom_where.push_str(" OR (ID_amis = ?) ");
        db_query = db_query.add_custom_where_argument_user_id(user_id);
    }

    custom_where.push_str(")");
    // ============= /PERMISSION CONDITIONS =================


    // ============== START POINT CONDITION =================
    if query.start_from != 0 {
        custom_where.push_str(" AND ID <= ?");
        db_query = db_query.add_custom_where_argument_u64(query.start_from);
    }
    // ============== /START POINT CONDITION ================


    // Perform the request
    db_query
        .cond_user_id("ID_personne", target_id)
        .cond_u64("group_id", 0)
        .set_custom_where(&custom_where)
        .set_order("ID DESC")
        .set_limit(query.limit)
        .exec(db_to_post)
}

/// Get the list of posts of a group
fn get_group(query: &PostsQuery, group_id: &GroupID) -> ResultBoxError<Vec<Post>> {
    let membership = groups_helper::get_membership_level(group_id, query.user_id.clone())?;

    let can_see_all_posts = membership <= GroupMembershipLevel::MEMBER;
    let visibility_level = match can_see_all_posts {
        true => PostVisibilityLevel::VISIBILITY_GROUP_MEMBERS,
        false => PostVisibilityLevel::VISIBILITY_FRIENDS
    };

    // Prepare request
    let mut db_query = database::QueryInfo::new(POSTS_TABLE);
    let mut custom_where = String::new();

    // =============== VISIBILITY CONDITION ================
    custom_where.push_str("(niveau_visibilite <= ?)");
    db_query = db_query.add_custom_where_argument_u32(visibility_level.to_db());
    // ============== /VISIBILITY CONDITION ================

    // ================== START POINT ======================
    if query.start_from > 0 {
        custom_where.push_str(" AND ID <= ?");
        db_query = db_query.add_custom_where_argument_u64(query.start_from);
    }
    // ================== /START POINT =====================

    db_query
        .cond_group_id("group_id", group_id)
        .set_custom_where(&custom_where)
        .set_order("ID DESC")
        .set_limit(query.limit)
        .exec(db_to_post)
}

/// Get the latest posts of a user
pub fn get_latest(query: &PostsQuery, include_group_posts: bool) -> ResultBoxError<Vec<Post>> {
    let user_id = query.user_id.as_ref().ok_or(ExecError::new("Can not get latest posts of no user!"))?;

    let visibility_level = PostVisibilityLevel::VISIBILITY_FRIENDS;

    // Get the list of friends of the user
    let friends_list = friends_helper::GetFriendsQuery::new(user_id)
        .set_only_accepted(true)
        .set_only_following(true)
        .exec()?;

    // Prepare the request
    let mut db_query = database::QueryInfo::new(POSTS_TABLE);
    let mut custom_where = String::new();

    // ================== MEMBERSHIP CONDITION ======================
    custom_where.push_str("(");

    // ========== FRIENDS POSTS ===========
    custom_where.push_str("(group_id = 0 AND niveau_visibilite <= ? AND (ID_personne = ?");
    db_query = db_query.add_custom_where_argument_u32(visibility_level.to_db());
    db_query = db_query.add_custom_where_argument_user_id(&user_id);

    for f in &friends_list {
        custom_where.push_str(" OR ID_personne = ?");
        db_query = db_query.add_custom_where_argument_user_id(&f.friend_id);
    };
    custom_where.push_str("))");
    // ========== /FRIENDS POSTS ==========

    // =========== GROUPS POSTS ===========
    if include_group_posts {
        let groups = groups_helper::get_list_user(user_id, true)?;

        for g in &groups {
            custom_where.push_str(" OR group_id = ?");
            db_query = db_query.add_custom_where_argument_group_id(g);
        };
    }
    // ========== /GROUPS POSTS ===========

    custom_where.push_str(")");
    // ================== /MEMBERSHIP CONDITION =====================


    // ======================= START POINT ==========================
    if query.start_from > 0 {
        custom_where.push_str("AND ID <= ?");
        db_query = db_query.add_custom_where_argument_u64(query.start_from);
    }
    // ====================== /START POINT ==========================

    db_query
        .set_custom_where(&custom_where)
        .set_order("ID DESC")
        .set_limit(query.limit)
        .exec(db_to_post)
}

/// Get information about a single post
pub fn get_single(post_id: u64) -> ResultBoxError<Post> {
    database::QueryInfo::new(POSTS_TABLE)
        .cond_u64("ID", post_id)
        .query_row(db_to_post)
}

/// Get the entire list of posts of a given user + the posts created on user's page
pub fn export_all_posts_user(user_id: &UserID) -> ResultBoxError<Vec<Post>> {
    database::QueryInfo::new(POSTS_TABLE)
        .set_custom_where("ID_personne = ? OR ID_amis = ?")
        .add_custom_where_argument_user_id(user_id)
        .add_custom_where_argument_user_id(user_id)
        .exec(db_to_post)
}

/// Get the entire list of posts of a given group
pub fn export_all_posts_group(group_id: &GroupID) -> ResultBoxError<Vec<Post>> {
    database::QueryInfo::new(POSTS_TABLE)
        .cond_group_id("group_id", group_id)
        .exec(db_to_post)
}

/// Get the access level of a user over a post
pub fn get_access_level(p: &Post, user_id: &Option<UserID>) -> ResultBoxError<PostAccessLevel> {
    if user_id == &p.user_id.as_option() {
        return Ok(PostAccessLevel::FULL_ACCESS);
    }

    match &p.target_page {
        // User page
        PostPageKind::PAGE_KIND_USER(user_page_id) => {
            if &user_page_id.as_option() == user_id {
                return Ok(PostAccessLevel::INTERMEDIATE_ACCESS);
            }

            return match p.visibility {
                PostVisibilityLevel::VISIBILITY_PUBLIC => {
                    if user_helper::can_see_user_page(user_id.as_ref().unwrap_or(&UserID::invalid()), user_page_id)? {
                        Ok(PostAccessLevel::BASIC_ACCESS)
                    } else {
                        Ok(PostAccessLevel::NO_ACCESS)
                    }
                }

                PostVisibilityLevel::VISIBILITY_FRIENDS => {
                    if user_id.is_some() && friends_helper::are_friend(user_id.as_ref().unwrap_or(&UserID::invalid()), user_page_id)? {
                        Ok(PostAccessLevel::BASIC_ACCESS)
                    } else {
                        Ok(PostAccessLevel::NO_ACCESS)
                    }
                }

                // No access to posts with restricted visibility
                PostVisibilityLevel::VISIBILITY_USER => Ok(PostAccessLevel::NO_ACCESS),
                _ => Ok(PostAccessLevel::NO_ACCESS),
            };
        }

        // Group page
        PostPageKind::PAGE_KIND_GROUP(group_id) => {
            let access_level = groups_helper::get_membership_level(group_id, user_id.clone())?;

            // Moderators & administrators
            if access_level < GroupMembershipLevel::MEMBER {
                Ok(PostAccessLevel::INTERMEDIATE_ACCESS)
            } else if access_level == GroupMembershipLevel::MEMBER {
                Ok(PostAccessLevel::BASIC_ACCESS)
            } else if p.visibility != PostVisibilityLevel::VISIBILITY_PUBLIC || !groups_helper::is_open(group_id)? {
                Ok(PostAccessLevel::NO_ACCESS)
            } else {
                Ok(PostAccessLevel::BASIC_ACCESS)
            }
        }
    }
}

/// Check out whether it is possible to create comments on a post or not
pub fn allow_comments_on_post(p: &Post) -> ResultBoxError<bool> {
    Ok(
        !p.is_on_user_page() ||
            user_helper::allow_comments(p.user_page_id().unwrap_or(&UserID::invalid()))?)
}

/// Set a new visibility level to a post
pub fn set_level(post_id: u64, level: PostVisibilityLevel) -> ResultBoxError {
    database::UpdateInfo::new(POSTS_TABLE)
        .cond_u64("ID", post_id)
        .set_u32("niveau_visibilite", level.to_db())
        .exec()
}

/// Set a new content to the post
pub fn set_content(post_id: u64, new_content: &str) -> ResultBoxError {
    database::UpdateInfo::new(POSTS_TABLE)
        .cond_u64("ID", post_id)
        .set_str("texte", new_content)
        .exec()
}

/// Delete a post
pub fn delete(p: &Post) -> ResultBoxError {
    // TODO : delete all the notifications related with the post

    // Delete all the likes associated with the post
    likes_helper::delete_all(p.id, LikeType::POST)?;

    // Delete all the comments associated to the post
    comments_helper::delete_all(p.id)?;

    // Delete associated file / resource (if any)
    match &p.kind {

        // Image / PDF
        PostKind::POST_KIND_IMAGE(file) | PostKind::POST_KIND_PDF(file) => {
            let path = user_data_path(file.path.as_ref());
            if path.exists() {
                std::fs::remove_file(path)?;
            }
        }

        // Survey
        PostKind::POST_KIND_SURVEY => {
            if survey_helper::exists(p.id)? {
                survey_helper::delete(p.id)?;
            }
        }

        _ => { /* Nothing to be done */ }
    }

    // Remove the post from the database
    database::DeleteQuery::new(POSTS_TABLE)
        .cond_u64("ID", p.id)
        .exec()?;

    Ok(())
}

/// Delete all the posts related with a group
pub fn delete_all_group(group_id: &GroupID) -> ResultBoxError {
    for post in export_all_posts_group(group_id)? {
        delete(&post)?;
    }

    Ok(())
}

/// Get all the posts that use of movie
pub fn get_posts_for_movie(m: &Movie) -> ResultBoxError<Vec<Post>> {
    database::QueryInfo::new(POSTS_TABLE)
        .cond_u64("idvideo", m.id)
        .exec(db_to_post)
}

/// Delete all the posts associated with a movie
pub fn delete_all_with_movie(m: &Movie) -> ResultBoxError {
    for post in get_posts_for_movie(m)? {
        delete(&post)?;
    }

    Ok(())
}

/// Turn a post into a database entry
fn db_to_post(res: &database::RowResult) -> ResultBoxError<Post> {
    let user_id = if res.get_u64("ID_amis")? == 0 {
        res.get_user_id("ID_personne")
    } else {
        res.get_user_id("ID_amis")
    }?;

    let target_page = if res.get_u64("group_id")? == 0 {
        PostPageKind::PAGE_KIND_USER(res.get_user_id("ID_personne")?)
    } else {
        PostPageKind::PAGE_KIND_GROUP(res.get_group_id("group_id")?)
    };

    let file = match res.get_optional_str("path")? {
        None => None,
        Some(path) => Some(PostFile {
            path,
            size: res.get_usize("size").unwrap_or(0),
            file_type: res.get_optional_str("file_type")?,
        }),
    };

    let mut post = Post {
        // General information
        id: res.get_u64("ID")?,
        user_id: user_id.clone(),
        time_create: res.get_u64("time_insert").unwrap_or(time()),
        target_page,
        content: res.get_optional_str("texte")?,
        visibility: PostVisibilityLevel::from_db(res.get_u32("niveau_visibilite")?),
        kind: PostKind::POST_KIND_TEXT,
    };

    let file = file.ok_or(ExecError::new("A file is required with this post type!"));

    match res.get_str("type")?.as_str() {
        "image" => post.kind = POST_KIND_IMAGE(file?),

        "webpage_link" => post.kind = POST_KIND_WEBLINK(PostWebLink {
            url: res.get_str("url_page")?,
            title: res.get_optional_str("titre_page")?,
            description: res.get_optional_str("description_page")?,
            image: res.get_optional_str("image_page")?,
        }),

        "pdf" => post.kind = POST_KIND_PDF(file?),

        "video" => post.kind = POST_KIND_MOVIE(res.get_u64("idvideo")?),

        "count_down" => post.kind = POST_KIND_COUNTDOWN(res.get_u64("time_end").unwrap_or(0)),

        "sondage" => post.kind = POST_KIND_SURVEY,

        "youtube" => post.kind = POST_KIND_YOUTUBE(res.get_str("path")?),

        _ => {}
    }

    Ok(post)
}