use chrono::Duration;
use serenity::{
    client::Context,
    model::{
        id::{
            ChannelId,
            MessageId,
        },
        permissions::Permissions,
    },
};
use std::process::Stdio;

use lazy_static::lazy_static;
use log::debug;
use regex::{
    Match,
    Regex,
};
use serenity::all::{
    CreateMessage,
    Message,
};
use url::Url;

use crate::{
    commands::songbird,
    Result,
    CONFIG,
};

pub async fn currently_playing(ctx: &Context, msg: &Message) -> bool {
    let (_sb, call) = songbird(ctx, msg).await.expect("no songbird");

    let call = call.lock().await;
    call.queue().current().is_some()
}

pub async fn users_listening(ctx: &Context) -> Result<bool> {
    let channel = CONFIG.discord.voice_channel().to_channel(&ctx).await?;

    let res = channel
        .guild()
        .and_then(|ch| ch.guild(&ctx))
        .map(|g| {
            (&g.voice_states)
                .into_iter()
                .any(|(_, state)| state.channel_id == Some(CONFIG.discord.voice_channel()))
        })
        .unwrap_or(false);

    Ok(res)
}

#[inline]
pub async fn send(
    ctx: &Context,
    channel: ChannelId,
    text: impl AsRef<str>,
    tts: bool,
) -> Result<()> {
    send_result(ctx, channel, text, tts).await.map(|_| ())
}

pub async fn send_result(
    ctx: &Context,
    channel: ChannelId,
    text: impl AsRef<str>,
    tts: bool,
) -> Result<MessageId> {
    let text = text.as_ref();
    debug!("sending message {:?} to channel {:?} (tts: {})", text, channel, tts);

    let result = channel.send_message(ctx, CreateMessage::default().content(text).tts(tts)).await?;
    Ok(result.id)
}

lazy_static! {
    static ref REQUIRED_PERMS: Permissions = Permissions::EMBED_LINKS
        | Permissions::ADD_REACTIONS
        | Permissions::SEND_MESSAGES
        | Permissions::SEND_TTS_MESSAGES
        | Permissions::MENTION_EVERYONE
        | Permissions::USE_EXTERNAL_EMOJIS
        | Permissions::CONNECT
        | Permissions::SPEAK
        | Permissions::CHANGE_NICKNAME
        | Permissions::USE_VAD
        | Permissions::ATTACH_FILES;
}

lazy_static! {
    pub static ref OAUTH_URL: Url = Url::parse(&format!(
        "https://discordapp.com/api/oauth2/authorize?scope=bot&permissions={}&client_id={}",
        REQUIRED_PERMS.bits(),
        CONFIG.discord.auth.client_id,
    ))
    .unwrap();
}

pub async fn ytdl_url(uri: &str) -> Result<String> {
    use serde_json::Value;
    use tokio::process::Command;

    lazy_static! {
        static ref YTDL_COMMAND: String = {
            let result = CONFIG.ytdl.clone().unwrap_or("youtube-dl".to_owned());
            log::debug!("got ytdl: {}", result);

            result
        };
    }

    let args = [
        "-f",
        "webm[abr>0]/bestaudio/best",
        "--no-playlist",
        "--print-json",
        "--skip-download",
        uri,
    ];

    let out = Command::new(&*YTDL_COMMAND).args(&args).stdin(Stdio::null()).output().await?;

    if !out.status.success() {
        return Err(anyhow::anyhow!("running ytdl: {out:?}"));
    }

    let value = serde_json::from_reader(&out.stdout[..])?;
    let mut obj = match value {
        Value::Object(obj) => obj,
        other => return Err(anyhow::anyhow!("ytdl output not object: {other:?}")),
    };

    match obj.remove("url") {
        Some(v) => match v {
            Value::String(uri) => Ok(uri),
            other => Err(anyhow::anyhow!("url not string: {other:?}")),
        },
        None => Err(anyhow::anyhow!("no url")),
    }
}
pub fn parse_times<A: AsRef<str>>(s: A) -> (Option<Duration>, Option<Duration>) {
    lazy_static! {
        static ref START_REGEX: Regex =
            Regex::new(r"(?:start|begin(?:ning)?)\s*=?\s*(?:(?P<hours>\d+)h\s?)?(?:(?P<minutes>\d+)m\s?)?(?:(?P<seconds>\d+)s?)?").unwrap();

        static ref DUR_REGEX: Regex =
            Regex::new(r"dur(?:ation)?\s*=?\s*(?:(?P<hours>\d+)h\s?)?(?:(?P<minutes>\d+)m\s?)?(?:(?P<seconds>\d+)s?)?").unwrap();

        static ref END_REGEX: Regex =
            Regex::new(r"(?:end|term(?:inate|ination)?)\s*=?\s*(?:(?P<hours>\d+)h\s?)?(?:(?P<minutes>\d+)m\s?)?(?:(?P<seconds>\d+)s?)?").unwrap();
    }

    fn parse_match(m: Option<Match>) -> u64 {
        m.and_then(|s| s.as_str().parse::<u64>().ok()).unwrap_or(0)
    }

    fn parse_captures<B: AsRef<str>>(r: &Regex, s: B) -> Option<Duration> {
        r.captures(s.as_ref()).map(|capt| {
            let hours = parse_match(capt.name("hours"));
            let minutes = parse_match(capt.name("minutes"));
            let seconds = parse_match(capt.name("seconds"));

            let result = Duration::hours(hours as i64)
                + Duration::minutes(minutes as i64)
                + Duration::seconds(seconds as i64);

            assert!(result >= Duration::zero());

            result
        })
    }

    let start_time = parse_captures(&START_REGEX, &s);
    let dur = parse_captures(&DUR_REGEX, &s);
    let end_time = parse_captures(&END_REGEX, s)
        .or_else(|| start_time.and_then(|start| dur.map(|d| start + d)));

    (start_time, end_time)
}