#![allow(clippy::cast_possible_wrap, clippy::cast_sign_loss)]

use poise::serenity_prelude::{ChannelId, GuildId};
use sqlx::{migrate::MigrateDatabase, Sqlite, SqlitePool};
use tracing::{error, info, debug};

pub type Result<T> = ::std::result::Result<T, sqlx::Error>;

pub struct Database(SqlitePool);

impl Database {
    /// Initialize Sqlite database.
    ///
    /// The Sqlite database should already exist and have its
    /// migrations already executed.
    ///
    /// # Errors
    ///
    /// This function will return an error if the Sqlite pool fails to
    /// create.
    pub async fn new() -> Result<Self> {
        let url = "sqlite:p4bl0t.db";
        if !Sqlite::database_exists(url).await? {
            info!("Creating database");
            Sqlite::create_database(url).await?;
            info!("Database created");
        }
        debug!("Getting pool connection");
        let pool = SqlitePool::connect(url).await?;
        info!("Running migrations");
        sqlx::migrate!().run(&pool).await?;
        debug!("Database initialized");
        Ok(Self(pool))
    }

    /// Return from database all channels registered as loggers for a
    /// guild.
    ///
    /// # Errors
    ///
    /// This function will return an error if `sqlx` does so.
    pub async fn get_logging_channels(
        &self,
        guild_id: GuildId,
    ) -> Result<Vec<ChannelId>> {
        let guild_id = guild_id.0 as i64;
        sqlx::query!(
            r#"
SELECT channel_id
FROM guild_log_channels
WHERE guild_id = ?1"#,
            guild_id
        )
        .fetch_all(&self.0)
        .await
        .map_err(|e| {
            error!(
                "Error getting logging channels for guild {guild_id}: {e:?}"
            );
            e
        })
        .map(|channels| {
            channels
                .iter()
                .map(|id| ChannelId(id.channel_id as u64))
                .collect()
        })
    }

    /// Adds a channel as a logger for a guild.
    ///
    /// # Errors
    ///
    /// This function will return an error if `sqlx` does so. This may
    /// be either a database issue, or a channel is already registered
    /// as a guild's logger, therefore violating the unicity
    /// constraint for guild ID and channel ID pairs.
    pub async fn set_logging_channel(
        &self,
        guild_id: GuildId,
        channel_id: ChannelId,
    ) -> Result<()> {
        let guild_id = guild_id.0 as i64;
        let channel_id = channel_id.0 as i64;
        let mut conn = self.0.acquire().await?;

        sqlx::query!(r#"
INSERT INTO guild_log_channels (guild_id, channel_id)
VALUES ( ?1, ?2 )"#,
            guild_id,
            channel_id
        )
        .execute(&mut *conn)
        .await
        .map_err(|e| {
            error!("Error setting channel {channel_id} as logger for guild {guild_id}: {e:?}");
            e
        })
        .map(|_| ())
    }

    /// Unregister a channel as a logger for a guild.
    ///
    /// This function will return a success value even if `channel`
    /// was not a logger of `guild` already.
    ///
    /// # Errors
    ///
    /// This function will return an error if `sqlx` does so.
    pub async fn remove_logging_channel(
        &self,
        guild: GuildId,
        channel: ChannelId,
    ) -> Result<()> {
        let guild_id = guild.0 as i64;
        let channel_id = channel.0 as i64;
        let mut conn = self.0.acquire().await?;
        sqlx::query!(r#"
DELETE FROM guild_log_channels
WHERE guild_id = ?1 AND channel_id = ?2"#,
                     guild_id,
                     channel_id)
            .execute(&mut *conn)
            .await
            .map_err(|e| {
                error!("Error removing channel {channel_id} as a logger for guild {guild_id}: {e:?}");
                e
            })
            .map(|_| ())
    }
}