use std::collections::HashMap;
use std::sync::Arc;

use chrono::{DateTime, NaiveDateTime, Utc};
use percent_encoding::{utf8_percent_encode, AsciiSet, CONTROLS};
use serenity::framework::standard::{CommandError, CommandResult};
use serenity::model::channel::{Message, Reaction};
use serenity::model::id::ChannelId;
use serenity::model::user::User;
use serenity::prelude::{Context, TypeMap};
use serenity::utils::Colour;
use tokio::sync::RwLockReadGuard;

use crate::database::models::Event;
use crate::discord::{get_db, DraftEvent};
use crate::hypebot_config::HypeBotConfig;
use crate::reminder::Reminders;
use crate::{discord, INTERESTED_EMOJI, UNINTERESTED_EMOJI};

/// Send a message to a reaction user
pub async fn send_message_to_reaction_users(ctx: &Context, reaction: &Reaction, msg_text: &str) {
    if let Ok(db) = get_db(&ctx.data.read().await).await {
        let message_id = reaction.message_id.0.to_string();

        let event = match db.get_event_by_msg_id(&message_id) {
            Some(event) => event,
            None => {
                return;
            }
        };

        let event_utc_time = DateTime::<Utc>::from_utc(event.event_time, Utc);
        let current_utc_time = chrono::offset::Utc::now();

        let msg;

        if event_utc_time > current_utc_time {
            // Format message
            let mut fmt = HashMap::new();
            fmt.insert("event".to_string(), event.event_name);
            msg = strfmt::strfmt(msg_text, &fmt).unwrap();

            if let Ok(user) = reaction.user(&ctx).await {
                send_dm_message(&ctx, user, &msg).await;
            }
        }
    }
}

/// Send a DM message to a user
pub async fn send_dm_message(ctx: &Context, user: User, message: &str) {
    if let Ok(dm_channel) = user.create_dm_channel(ctx).await {
        dm_channel
            .send_message(ctx, |m| m.content(message))
            .await
            .ok();
    }
}

pub const FRAGMENT: &AsciiSet = &CONTROLS.add(b' ').add(b'"').add(b'<').add(b'>').add(b'`');

/// Sends the event message to the event channel
pub async fn send_event_msg(
    ctx: &Context,
    config: &HypeBotConfig,
    channel_id: u64,
    event: &Event,
    react: bool,
) -> serenity::Result<Message> {
    let channel = ctx.http.get_channel(channel_id).await?;

    let utc_time = DateTime::<Utc>::from_utc(event.event_time, Utc);

    let native_time = utc_time.with_timezone(&config.event_timezone);

    let ping_roles = config
        .ping_roles
        .clone()
        .into_iter()
        .map(|role| format!("<@&{}>", role))
        .collect::<Vec<String>>()
        .join(" ");

    // Send message
    let msg = channel.id().send_message(&ctx, |m| {
        m.embed(|e| {
            e.title(event.event_name.clone())
                .color(Colour::PURPLE)
                .description(format!(
                    "**{}**\n{}\n\n[Click Here For A Countdown]({})\n\nReact with {} below to receive event reminders!",
                    native_time.format("%A, %B %d @ %I:%M %P %t %Z"),
                    event.event_desc,
                    get_countdown_link(&event.event_name, &utc_time),
                    INTERESTED_EMOJI
                ))
                .thumbnail(event.thumbnail_link.clone())
                .footer(|f| f.text("Local Event Time"))
                .timestamp(utc_time.to_rfc3339())
                .field("Location", &event.event_loc, true)
                .field("Organizer", &event.organizer, true)
        }).content(ping_roles)
    }).await?;

    if react {
        // Add reacts
        msg.react(ctx, INTERESTED_EMOJI).await?;
        msg.react(ctx, UNINTERESTED_EMOJI).await?;
    }

    Ok(msg)
}

/// Updates the draft event stored in the context data
#[allow(clippy::too_many_arguments)]
pub async fn update_draft_event(
    ctx: &Context,
    event_name: String,
    event_desc: String,
    organizer: String,
    location: String,
    thumbnail: String,
    event_time: NaiveDateTime,
    creator_id: u64,
) -> CommandResult {
    let mut data = ctx.data.write().await;
    let draft_event = data
        .get_mut::<DraftEvent>()
        .ok_or_else(|| CommandError::from("Unable get draft event!".to_string()))?;

    let new_draft_event = DraftEvent {
        event: Event {
            event_name,
            event_desc,
            event_loc: location,
            organizer,
            event_time,
            message_id: "".to_string(),
            thumbnail_link: thumbnail,
        },
        creator_id,
    };

    *draft_event = Arc::new(new_draft_event);

    Ok(())
}

/// Sends the draft event stored in the context data
pub async fn send_draft_event(ctx: &Context, channel: ChannelId) -> CommandResult {
    let data = ctx.data.read().await;
    let config = get_config(&data).await?;
    let draft_event = discord::get_draft_event(&data).await?;

    channel
        .send_message(&ctx, |m| {
            m.content("Draft message, use the `confirm` command to post it.".to_string())
        })
        .await?;
    send_event_msg(ctx, &config, channel.0, &draft_event.event, false).await?;
    Ok(())
}

/// Gets the config from context data
pub async fn get_config(
    data: &RwLockReadGuard<'_, TypeMap>,
) -> std::result::Result<Arc<HypeBotConfig>, CommandError> {
    let config = data
        .get::<HypeBotConfig>()
        .ok_or_else(|| CommandError::from("Unable to get config".to_string()))?;

    Ok(config.clone())
}

/// Schedule event reminders
pub async fn schedule_event(ctx: &Context, event: &Event) {
    let config = get_config(&ctx.data.read().await)
        .await
        .expect("Unable to get config");

    let mut data = ctx.data.write().await;

    let reminders = data.get_mut::<Reminders>().unwrap();

    reminders.add_reminders(event, &*config);
}

/// Schedule all events
pub async fn schedule_all_events(ctx: &Context) {
    let db = get_db(&ctx.data.read().await)
        .await
        .expect("Could not get database");

    for event in db.get_all_events() {
        schedule_event(&ctx, &event).await;
    }
}

/// Delete event
pub async fn delete_event(ctx: &Context, event: &Event) -> CommandResult {
    let config = get_config(&ctx.data.read().await)
        .await
        .expect("Unable to get config");

    let db = get_db(&ctx.data.read().await)
        .await
        .expect("Unable to get db");

    let message_id = event.message_id.parse::<u64>()?;
    let message = ctx
        .http
        .get_message(config.event_channel, message_id)
        .await?;
    let cancel_msg = format!("**{}** has been canceled!", event.event_name.clone());

    // Only send a cancel message if the even has not already happened
    if event.event_time > Utc::now().naive_utc() {
        if let Ok(reaction_users) = message
            .reaction_users(&ctx.http, INTERESTED_EMOJI, None, None)
            .await
        {
            for user in reaction_users {
                send_dm_message(ctx, user, &cancel_msg).await;
            }
        }
    }

    db.remove_event(event)?;

    message.delete(ctx).await?;

    if let Some(reminders) = ctx.data.write().await.get_mut::<Reminders>() {
        reminders.remove_reminders(&event);
    }

    Ok(())
}

/// Create a countdown link for the event
pub fn get_countdown_link(event_name: &str, utc: &DateTime<Utc>) -> String {
    let msg = utf8_percent_encode(event_name, FRAGMENT);
    let time = utc.format("%G%m%dT%H%M").to_string();

    format!(
        "https://www.timeanddate.com/countdown/generic?iso={}&p0=&msg={}&font=sanserif&csz=1",
        time, msg
    )
}