#![feature(option_result_contains)]
use async_trait::async_trait;
use fancy_regex::Regex;
use lazy_static::lazy_static;
use serenity::{
    model::{
        channel::ReactionType,
        id::{ChannelId, EmojiId, GuildId},
        prelude::*,
    },
    prelude::*,
    Client,
};

struct Handler;

lazy_static! {
    static ref SERVER_ID: GuildId = GuildId(std::env::args().nth(1).unwrap().parse().unwrap());
    static ref MEME_CHANNEL: ChannelId =
        ChannelId(std::env::args().nth(2).unwrap().parse().unwrap());
    static ref RETARD_REGEX: Regex =
        Regex::new("(?<!(. | j| d|op|in|us|ng|si|tw|dd|nd| n))a( |$)").unwrap();
}

#[async_trait]
impl EventHandler for Handler {
    async fn message(&self, ctx: Context, message: Message) {
        if let Err(e) = handle_message(ctx, message).await {
            eprintln!("Error during command execution: {e}");
        }
    }
}

fn fix_spelling(msg: &str) -> String {
    RETARD_REGEX.replace_all(&msg, "**er** ").trim().to_owned()
}

async fn handle_message(ctx: Context, message: Message) -> Result<(), serenity::Error> {
    if message.guild_id != Some(*SERVER_ID) {
        return Ok(());
    }
    /*
    // That other idiot who ends words with “a” instead of “er”
    if message.author.id == 261246789942902794
        && RETARD_REGEX.is_match(&message.content).contains(&true)
        && !message.content.starts_with("a ")
        && !message.content.starts_with("ja ")
        && !message.content.starts_with("da ")
        && !message.content.starts_with("na ")
    {
        message.delete(&ctx).await?;
        let fixed = fix_spelling(&message.content);
        message
            .channel_id
            .say(&ctx, &format!("{}: {}", message.author.mention(), fixed))
            .await?;
    }
    */
    if message.channel_id == *MEME_CHANNEL && is_meme(&message) {
        react(&ctx, &message, 748564944449962017, "based").await?;
        react(&ctx, &message, 748564944819060856, "cringe").await?;
    };
    let content = message.content_safe(&ctx).await.to_lowercase();
    if content.contains("everyone") && content.contains("nitro") && content.contains("http") {
        println!(
            "Deleting probable spam from user {}: “{}”",
            message.author.name, content
        );
        message.delete(&ctx).await?;
        message.channel_id.say(
            &ctx,
            &format!("{}: your message has been deleted because it triggered my spam filter. If you believe this to be in error, please contact the mods.", message.author.mention())
        ).await?;
    }
    Ok(())
}

async fn react(
    ctx: &Context,
    msg: &Message,
    emoji: u64,
    name: &str,
) -> Result<(), serenity::Error> {
    let reaction = ReactionType::Custom {
        animated: false,
        id: EmojiId(emoji),
        name: Some(name.to_string()),
    };
    msg.react(ctx, reaction).await?;
    Ok(())
}

fn is_meme(msg: &Message) -> bool {
    !msg.attachments.is_empty() || msg.content.to_lowercase().contains("http")
}

#[tokio::main]
async fn main() {
    let mut client =
        Client::builder(std::env::var("DISCORD_TOKEN").expect("no token in environment"))
            .event_handler(Handler)
            .await
            .expect("Could not create client");
    client.start().await.expect("could not start");
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn fix_spelling_test() {
        let msg = "aba ihr meint es ja bessa zu wissen ohne euch damit auseinanda gesetzt zu haben oda zu wollen";
        let expected = "ab**er** ihr meint es ja bess**er** zu wissen ohne euch damit auseinand**er** gesetzt zu haben od**er** zu wollen";
        assert_eq!(fix_spelling(msg), expected);
        let msg = "your a bad person";
        assert_eq!(fix_spelling(msg), msg);
        let msg = "china usa europa da ja manga asia etwa unsa";
        let expected = "china usa europa da ja manga asia etwa uns**er**";
        assert_eq!(fix_spelling(msg), expected);
        let msg = "guta tip";
        let expected = "gut**er** tip";
        assert_eq!(fix_spelling(msg), expected);
    }
}