use crate::{
    errors::HandlerUsed,
    markups::deletion_markup,
    models::{DecryptedAccount, User},
    utils::delete_optional,
    MainDialogue,
};
use futures::TryStreamExt;
use itertools::Itertools;
use sea_orm::prelude::*;
use std::fmt::Write;
use teloxide::{adaptors::Throttle, net::Download, prelude::*, types::Document};
use tokio::task::spawn_blocking;
use trim_in_place::TrimInPlace;

#[inline]
async fn download_file(bot: &Throttle<Bot>, document: &Document) -> crate::Result<Vec<u8>> {
    let path = bot.get_file(document.file.id.as_str()).await?.path;
    let mut data = Vec::with_capacity(document.file.size as usize);
    bot.download_file_stream(&path)
        .try_for_each(|bytes| {
            data.extend(bytes);
            async { Ok(()) }
        })
        .await?;
    Ok(data)
}

#[inline]
fn process_accounts(accounts: &mut [DecryptedAccount]) -> crate::Result<Result<(), String>> {
    for account in accounts.iter_mut() {
        account.name.trim_in_place();
        account.login.trim_in_place();
        account.password.trim_in_place();
    }

    accounts.sort_unstable_by(|a, b| a.name.cmp(&b.name));

    let mut duplicates = Vec::new();
    let mut invalid = Vec::new();

    accounts
        .iter()
        .dedup_by_with_count(|a, b| a.name == b.name)
        .for_each(|(count, account)| {
            if count != 1 {
                duplicates.push(account.name.as_str());
            } else if !account.validate() {
                invalid.push(account.name.as_str());
            }
        });

    if duplicates.is_empty() && invalid.is_empty() {
        return Ok(Ok(()));
    }

    let mut error_text = "Your accounts have the following problems:".to_owned();

    if !duplicates.is_empty() {
        write!(
            error_text,
            "\n\nDuplicate names:\n{:?}",
            duplicates.into_iter().format("\n")
        )?
    }

    if !invalid.is_empty() {
        write!(
            error_text,
            "\n\nInvalid account fields:\n{:?}",
            invalid.into_iter().format("\n")
        )?
    }

    error_text.push_str("\n\nFix these problems and send the file again");

    Ok(Err(error_text))
}

#[inline]
fn user_from_vec(vector: Vec<u8>) -> crate::Result<Result<User, String>> {
    let mut user: User = serde_json::from_slice(&vector)?;
    drop(vector);
    match process_accounts(&mut user.accounts)? {
        Ok(()) => Ok(Ok(user)),
        Err(error_text) => Ok(Err(error_text)),
    }
}

/// Function to handle GetUser state. It doesn't actually validate anything
pub async fn get_user(
    bot: Throttle<Bot>,
    msg: Message,
    db: DatabaseConnection,
    dialogue: MainDialogue,
    next: super::PackagedHandler<User>,
) -> crate::Result<()> {
    let mut handler = next.lock().await;
    delete_optional(&bot, handler.previous.as_ref()).await;

    if let Some("/cancel") = msg.text().map(str::trim_end) {
        dialogue.exit().await?;
        bot.send_message(msg.chat.id, "Successfully cancelled")
            .reply_markup(deletion_markup())
            .await?;
        return Ok(());
    }

    if handler.func.is_none() {
        let _ = dialogue.exit().await;
        return Err(HandlerUsed.into());
    }

    let document = match msg.document() {
        Some(document) => document,
        None => {
            let msg = bot
                .send_message(msg.chat.id, "You didn't send a file. Try again")
                .await?;
            handler.previous = Some(msg);
            return Ok(());
        }
    };

    match document.file_name.as_deref() {
        Some(name) if name.trim_end().ends_with(".json") => (),
        _ => {
            let msg = bot
                .send_message(
                    msg.chat.id,
                    "Invalid file name. You need to send a json file. Try again",
                )
                .await?;
            handler.previous = Some(msg);
            return Ok(());
        }
    }

    let data = download_file(&bot, document).await?;

    let user = match spawn_blocking(move || user_from_vec(data)).await? {
        Ok(Ok(user)) => user,
        Ok(Err(error_text)) => {
            let msg = bot.send_message(msg.chat.id, error_text).await?;
            handler.previous = Some(msg);
            return Ok(());
        }
        Err(_) => {
            let msg = bot
                .send_message(msg.chat.id, "Error parsing the json file. Try again")
                .await?;
            handler.previous = Some(msg);
            return Ok(());
        }
    };

    let func = handler.func.take().unwrap();
    drop(handler);

    if let Err(err) = func(bot, msg, db, dialogue.clone(), user).await {
        let _ = dialogue.exit().await;
        return Err(err);
    }
    Ok(())
}