use std::collections::HashSet;
use serde::Serialize;

use crate::database;
use crate::types::response::{Result, ResponseCode};

#[derive(Serialize)]
pub struct Post {
    pub post_id: u64,
    pub user_id: u64,
    pub content: String,
    pub likes: HashSet<u64>,
    pub comments: Vec<(u64, String)>,
    pub date: u64
}

impl Post {

    pub fn from_post_id(post_id: u64) -> Result<Self> {
        let Ok(Some(post)) = database::posts::get_post(post_id) else {
            return Err(ResponseCode::BadRequest.msg("Post does not exist"))
        };

        Ok(post)
    }

    // pub fn from_post_ids(post_ids: Vec<u64>) -> Vec<Self> {
    //     post_ids.iter().map(|id| {
    //         let Ok(post) = Post::from_post_id(*id) else {
    //             return None;
    //         };
    //         Some(post)
    //     }).flatten().collect()
    // }

    pub fn from_post_page(page: u64) -> Result<Vec<Self>> {
        let Ok(posts) = database::posts::get_post_page(page) else {
            return Err(ResponseCode::BadRequest.msg("Failed to fetch posts"))
        };
        Ok(posts)
    }

    pub fn from_user_id(user_id: u64) -> Result<Vec<Self>> {
        let Ok(posts) = database::posts::get_users_posts(user_id) else {
            return Err(ResponseCode::BadRequest.msg("Failed to fetch posts"))
        };
        Ok(posts)
    }

    pub fn new(user_id: u64, content: String) -> Result<Self> {
        let Ok(post) = database::posts::add_post(user_id, &content) else {
            return Err(ResponseCode::InternalServerError.msg("Failed to create post"))
        };

        Ok(post)
    }

    pub fn comment(&mut self, user_id: u64, content: String) -> Result<()> {
        self.comments.push((user_id, content));
        
        if database::posts::update_post(self.post_id, &self.likes, &self.comments).is_err() {
            return Err(ResponseCode::InternalServerError.msg("Failed to comment on post"))
        }

        Ok(())
    }

    pub fn like(&mut self, user_id: u64, state: bool) -> Result<()> {

        if state {
            self.likes.insert(user_id);
        } else {
            self.likes.remove(&user_id);
        }
        
        if database::posts::update_post(self.post_id, &self.likes, &self.comments).is_err() {
            return Err(ResponseCode::InternalServerError.msg("Failed to comment on post"))
        }

        Ok(())
    }
    
}