use std::time::{Duration, SystemTime, UNIX_EPOCH};

use rusqlite::Row;
use tracing::instrument;

use crate::types::comment::Comment;

use super::Database;

impl Database {
    pub fn init_comments(&self) -> Result<(), rusqlite::Error> {
        let sql = "
            CREATE TABLE IF NOT EXISTS comments (
                comment_id  INTEGER PRIMARY KEY AUTOINCREMENT,
                user_id     INTEGER NOT NULL,
                post_id     INTEGER NOT NULL,
                date        INTEGER NOT NULL,
                content     VARCHAR(255) NOT NULL,
                FOREIGN KEY(user_id) REFERENCES users(user_id),
                FOREIGN KEY(post_id) REFERENCES posts(post_id)
            );
        ";
        self.0.execute(sql, ())?;

        let sql2 = "CREATE INDEX IF NOT EXISTS post_ids on comments (post_id);";
        self.0.execute(sql2, ())?;

        Ok(())
    }

    fn comment_from_row(row: &Row) -> Result<Comment, rusqlite::Error> {
        let comment_id = row.get(0)?;
        let user_id = row.get(1)?;
        let post_id = row.get(2)?;
        let date = row.get(3)?;
        let content = row.get(4)?;

        Ok(Comment {
            comment_id,
            user_id,
            post_id,
            date,
            content,
        })
    }

    #[instrument(skip(self))]
    pub fn get_comments_page(
        &self,
        page: u64,
        post_id: u64,
    ) -> Result<Vec<Comment>, rusqlite::Error> {
        tracing::trace!("Retrieving comments page");
        let page_size = 5;
        let mut stmt = self.0.prepare(
            "SELECT * FROM comments WHERE post_id = ? ORDER BY comment_id ASC LIMIT ? OFFSET ?",
        )?;
        let row = stmt.query_map([post_id, page_size, page_size * page], |row| {
            let row = Self::comment_from_row(row)?;
            Ok(row)
        })?;
        Ok(row.into_iter().flatten().collect())
    }

    #[instrument(skip(self))]
    pub fn get_all_comments(&self) -> Result<Vec<Comment>, rusqlite::Error> {
        tracing::trace!("Retrieving comments page");
        let mut stmt = self
            .0
            .prepare("SELECT * FROM comments ORDER BY comment_id DESC")?;
        let row = stmt.query_map([], |row| {
            let row = Self::comment_from_row(row)?;
            Ok(row)
        })?;
        Ok(row.into_iter().flatten().collect())
    }

    #[instrument(skip(self))]
    pub fn add_comment(
        &self,
        user_id: u64,
        post_id: u64,
        content: &str,
    ) -> Result<Comment, rusqlite::Error> {
        tracing::trace!("Adding comment");
        let date = u64::try_from(
            SystemTime::now()
                .duration_since(UNIX_EPOCH)
                .unwrap_or(Duration::ZERO)
                .as_millis(),
        )
        .unwrap_or(0);
        let mut stmt = self.0.prepare(
            "INSERT INTO comments (user_id, post_id, date, content) VALUES(?,?,?,?) RETURNING *;",
        )?;
        let post = stmt.query_row((user_id, post_id, date, content), |row| {
            let row = Self::comment_from_row(row)?;
            Ok(row)
        })?;
        Ok(post)
    }
}