use std::str::FromStr;

use futures::TryStreamExt;
use moka::future::Cache;
use regex::Regex;
use strum_macros::EnumIter;
use teloxide::{
    adaptors::{CacheMe, Throttle},
    dispatching::UpdateFilterExt,
    dptree,
    prelude::*,
    types::*,
};
use tokio_util::compat::FuturesAsyncReadCompatExt;

use crate::{
    bots::{
        approved_bot::{
            services::{
                book_cache::{
                    download_file, get_cached_message,
                    types::{CachedMessage, DownloadFile},
                },
                book_library::get_book,
                donation_notificatioins::send_donation_notification,
            },
            tools::filter_callback_query,
        },
        BotHandlerInternal,
    },
    bots_manager::{AppState, BotCache},
};

use super::utils::{filter_command, CommandParse};

#[derive(Clone)]
pub struct DownloadData {
    pub format: String,
    pub id: u32,
}

impl CommandParse<Self> for DownloadData {
    fn parse(s: &str, bot_name: &str) -> Result<Self, strum::ParseError> {
        let re = Regex::new(r"^/d_(?P<file_format>[a-zA-Z0-9]+)_(?P<book_id>\d+)$").unwrap();

        let full_bot_name = format!("@{bot_name}");
        let after_replace = s.replace(&full_bot_name, "");

        let caps = re.captures(&after_replace);
        let caps = match caps {
            Some(v) => v,
            None => return Err(strum::ParseError::VariantNotFound),
        };

        let file_format = &caps["file_format"];
        let book_id: u32 = caps["book_id"].parse().unwrap();

        Ok(DownloadData {
            format: file_format.to_string(),
            id: book_id,
        })
    }
}

#[derive(Clone)]
pub struct StartDownloadData {
    pub id: u32,
}

impl ToString for StartDownloadData {
    fn to_string(&self) -> String {
        let StartDownloadData { id } = self;
        format!("/d_{id}")
    }
}

impl CommandParse<Self> for StartDownloadData {
    fn parse(s: &str, bot_name: &str) -> Result<Self, strum::ParseError> {
        let re = Regex::new(r"^/d_(?P<book_id>\d+)$").unwrap();

        let full_bot_name = format!("@{bot_name}");
        let after_replace = s.replace(&full_bot_name, "");

        let caps = re.captures(&after_replace);
        let caps = match caps {
            Some(v) => v,
            None => return Err(strum::ParseError::VariantNotFound),
        };

        let book_id: u32 = caps["book_id"].parse().unwrap();

        Ok(StartDownloadData { id: book_id })
    }
}

#[derive(Clone, EnumIter)]
pub enum DownloadQueryData {
    DownloadData { book_id: u32, file_type: String },
}

impl ToString for DownloadQueryData {
    fn to_string(&self) -> String {
        match self {
            DownloadQueryData::DownloadData { book_id, file_type } => {
                format!("d_{book_id}_{file_type}")
            }
        }
    }
}

impl FromStr for DownloadQueryData {
    type Err = strum::ParseError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let re = Regex::new(r"^d_(?P<book_id>\d+)_(?P<file_type>\w+)$").unwrap();

        let caps = re.captures(s);
        let caps = match caps {
            Some(v) => v,
            None => return Err(strum::ParseError::VariantNotFound),
        };

        let book_id: u32 = caps["book_id"].parse().unwrap();
        let file_type: String = caps["file_type"].to_string();

        Ok(DownloadQueryData::DownloadData { book_id, file_type })
    }
}

async fn _send_cached(
    message: &Message,
    bot: &CacheMe<Throttle<Bot>>,
    cached_message: CachedMessage,
) -> BotHandlerInternal {
    match bot
        .copy_message(
            message.chat.id,
            Recipient::Id(ChatId(cached_message.data.chat_id)),
            MessageId(cached_message.data.message_id),
        )
        .send()
        .await
    {
        Ok(_) => Ok(()),
        Err(err) => Err(Box::new(err)),
    }
}

async fn send_cached_message(
    message: Message,
    bot: CacheMe<Throttle<Bot>>,
    download_data: DownloadData,
    donation_notification_cache: Cache<ChatId, bool>,
    need_delete_message: bool,
) -> BotHandlerInternal {
    if let Ok(v) = get_cached_message(&download_data).await {
        if _send_cached(&message, &bot, v).await.is_ok() {
            if need_delete_message {
                bot.delete_message(message.chat.id, message.id).await?;
            }

            send_donation_notification(bot.clone(), message, donation_notification_cache).await?;

            return Ok(());
        }
    };

    send_with_download_from_channel(message, bot, download_data, donation_notification_cache, need_delete_message)
        .await?;

    Ok(())
}

async fn _send_downloaded_file(
    message: &Message,
    bot: CacheMe<Throttle<Bot>>,
    downloaded_data: DownloadFile,
    donation_notification_cache: Cache<ChatId, bool>,
) -> BotHandlerInternal {
    let DownloadFile {
        response,
        filename,
        caption,
    } = downloaded_data;

    let data = response
        .bytes_stream()
        .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))
        .into_async_read()
        .compat();

    let document: InputFile = InputFile::read(data).file_name(filename);

    bot.send_document(message.chat.id, document)
        .caption(caption)
        .send()
        .await?;

    send_donation_notification(bot, message.clone(), donation_notification_cache).await?;

    Ok(())
}

async fn send_with_download_from_channel(
    message: Message,
    bot: CacheMe<Throttle<Bot>>,
    download_data: DownloadData,
    donation_notification_cache: Cache<ChatId, bool>,
    need_delete_message: bool,
) -> BotHandlerInternal {
    match download_file(&download_data).await {
        Ok(v) => {
            _send_downloaded_file(&message, bot.clone(), v, donation_notification_cache).await?;

            if need_delete_message {
                bot.delete_message(message.chat.id, message.id).await?;
            }

            Ok(())
        },
        Err(err) => Err(err),
    }
}

async fn download_handler(
    message: Message,
    bot: CacheMe<Throttle<Bot>>,
    cache: BotCache,
    download_data: DownloadData,
    donation_notification_cache: Cache<ChatId, bool>,
    need_delete_message: bool,
) -> BotHandlerInternal {
    match cache {
        BotCache::Original => {
            send_cached_message(
                message,
                bot,
                download_data,
                donation_notification_cache,
                need_delete_message,
            )
            .await
        }
        BotCache::NoCache => {
            send_with_download_from_channel(
                message,
                bot,
                download_data,
                donation_notification_cache,
                need_delete_message,
            )
            .await
        }
    }
}

async fn get_download_keyboard_handler(
    message: Message,
    bot: CacheMe<Throttle<Bot>>,
    download_data: StartDownloadData,
) -> BotHandlerInternal {
    let book = match get_book(download_data.id).await {
        Ok(v) => v,
        Err(err) => {
            bot.send_message(message.chat.id, "Ошибка! Попробуйте позже :(")
                .send()
                .await?;

            return Err(err);
        }
    };

    let keyboard = InlineKeyboardMarkup {
        inline_keyboard: book
            .available_types
            .into_iter()
            .map(|item| -> Vec<InlineKeyboardButton> {
                vec![InlineKeyboardButton {
                    text: {
                        format!("📥 {item}")
                    },
                    kind: InlineKeyboardButtonKind::CallbackData(
                        (DownloadQueryData::DownloadData {
                            book_id: book.id,
                            file_type: item,
                        })
                        .to_string(),
                    ),
                }]
            })
            .collect(),
    };

    bot.send_message(message.chat.id, "Выбери формат:")
        .reply_markup(keyboard)
        .reply_to_message_id(message.id)
        .send()
        .await?;

    Ok(())
}

pub fn get_download_hander() -> crate::bots::BotHandler {
    dptree::entry()
        .branch(
            Update::filter_message()
                .chain(filter_command::<DownloadData>())
                .endpoint(
                    |message: Message,
                     bot: CacheMe<Throttle<Bot>>,
                     cache: BotCache,
                     download_data: DownloadData,
                     app_state: AppState| async move {
                        download_handler(
                            message,
                            bot,
                            cache,
                            download_data,
                            app_state.chat_donation_notifications_cache,
                            false,
                        )
                        .await
                    },
                ),
        )
        .branch(
            Update::filter_message()
                .chain(filter_command::<StartDownloadData>())
                .endpoint(
                    |message: Message,
                     bot: CacheMe<Throttle<Bot>>,
                     download_data: StartDownloadData| async move {
                        get_download_keyboard_handler(message, bot, download_data).await
                    },
                ),
        )
        .branch(
            Update::filter_callback_query()
                .chain(filter_callback_query::<DownloadQueryData>())
                .endpoint(
                    |cq: CallbackQuery,
                     download_query_data: DownloadQueryData,
                     bot: CacheMe<Throttle<Bot>>,
                     cache: BotCache,
                     app_state: AppState| async move {
                        match download_query_data {
                            DownloadQueryData::DownloadData { book_id, file_type } => {
                                download_handler(
                                    cq.message.unwrap(),
                                    bot,
                                    cache,
                                    DownloadData {
                                        format: file_type,
                                        id: book_id,
                                    },
                                    app_state.chat_donation_notifications_cache,
                                    true,
                                )
                                .await
                            }
                        }
                    },
                ),
        )
}