use core::fmt;
use serde::Serialize;
use std::collections::HashSet;
use tracing::instrument;

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

#[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 fmt::Debug for Post {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Post")
            .field("post_id", &self.post_id)
            .finish()
    }
}

impl Post {
    #[instrument()]
    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.text("Post does not exist"))
        };

        Ok(post)
    }

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

    #[instrument()]
    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.text("Failed to fetch posts"))
        };
        Ok(posts)
    }

    #[instrument()]
    pub fn reterieve_all() -> Result<Vec<Self>> {
        let Ok(posts) = database::posts::get_all_posts() else {
            return Err(ResponseCode::InternalServerError.text("Failed to fetch posts"))
        };
        Ok(posts)
    }

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

        Ok(post)
    }

    #[instrument()]
    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() {
            tracing::error!("Failed to comment on post");
            return Err(ResponseCode::InternalServerError.text("Failed to comment on post"));
        }

        Ok(())
    }

    #[instrument()]
    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() {
            tracing::error!("Failed to change like state on post");
            return Err(
                ResponseCode::InternalServerError.text("Failed to change like state on post")
            );
        }

        Ok(())
    }
}