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

use crate::constants::database_tables_names::POSTS_TABLE;
use crate::data::error::{ExecError, ResultBoxError};
use crate::data::group_member::GroupMembershipLevel;
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::{database, friends_helper, groups_helper, user_helper};
use crate::utils::date_utils::time;

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,
        }
    }
}


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 `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 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()))?)
}

/// 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)
}