#![cfg(target_os = "android")]
#![allow(non_snake_case)]

mod db;

use grammers_client::types::{Dialog as OgDialog, LoginToken};
use grammers_client::{Client, Config, InitParams};
use grammers_session::{PackedChat, Session, UpdateState};
use grammers_tl_types as tl;
use log;
use log::{error, info, Level};
use once_cell::sync::OnceCell;
use std::collections::HashMap;
use std::fmt;
use std::future::Future;
use std::net::SocketAddr;
use std::net::{Ipv4Addr, Ipv6Addr};
use std::sync::Mutex;
use std::time::SystemTime;
use tokio::runtime;
use tokio::runtime::Runtime;

include!(concat!(env!("OUT_DIR"), "/talaria.uniffi.rs"));

const LOG_MIN_LEVEL: Level = Level::Trace;
const LOG_TAG: &str = ".native.talari";
const API_ID: i32 = {
    let mut index = 0;
    let mut value = 0;
    let api_id = env!("TALARIA_API_ID");
    let bytes = api_id.as_bytes();
    while index < bytes.len() {
        match bytes[index] {
            b @ b'0'..=b'9' => value = value * 10 + (b - b'0') as i32,
            _ => panic!("non-digit character found in API ID"),
        }
        index += 1
    }
    value
};
const API_HASH: &str = env!("TALARIA_API_HASH");
const SERVER_ADDR: &str = env!("TALARIA_SERVER_ADDR");

static RUNTIME: OnceCell<Runtime> = OnceCell::new();
static CLIENT: OnceCell<Client> = OnceCell::new();
static DATABASE: Mutex<Option<sqlite::Connection>> = Mutex::new(None);

#[derive(Debug, Clone, Copy)]
pub enum NativeError {
    Initialization,
    Database,
    Network,
}

impl fmt::Display for NativeError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Initialization => write!(f, "a resource could not be initialized correctly"),
            Self::Database => write!(f, "a query to the local database failed"),
            Self::Network => write!(f, "a network request could not complete successfully"),
        }
    }
}

impl std::error::Error for NativeError {}

#[derive(Debug, Clone, Copy)]
pub enum MessageAck {
    Received,
    Seen,
    Sent,
}

#[derive(Debug, Clone)]
pub struct MessagePreview {
    sender: String,
    text: String,
    date: SystemTime,
    ack: MessageAck,
}

#[derive(Debug, Clone)]
pub struct Dialog {
    id: String,
    title: String,
    lastMessage: Option<MessagePreview>,
    pinned: bool,
}

type Result<T> = std::result::Result<T, NativeError>;

fn block_on<F: Future>(future: F) -> F::Output {
    if RUNTIME.get().is_none() {
        RUNTIME
            .set(
                runtime::Builder::new_current_thread()
                    .enable_all()
                    .build()
                    .unwrap(),
            )
            .ok();
    }

    RUNTIME.get().unwrap().block_on(future)
}

async fn init_client() -> Result<()> {
    android_logger::init_once(
        android_logger::Config::default()
            .with_min_level(LOG_MIN_LEVEL)
            .with_tag(LOG_TAG),
    );

    if CLIENT.get().is_some() {
        info!("Client is already initialized");
        return Ok(());
    }

    let guard = DATABASE.lock().unwrap();
    let conn = match guard.as_ref() {
        Some(c) => c,
        None => {
            error!("Database was not initialized");
            return Err(NativeError::Initialization);
        }
    };

    info!("Connecting to Telegram...");

    let session = Session::new();

    let sessions = db::get_sessions(conn).map_err(|_| NativeError::Database)?;
    if let Some(s) = sessions.get(0) {
        match (s.user_id, s.dc_id, s.bot) {
            (Some(id), Some(dc), Some(bot)) => session.set_user(id, dc, bot),
            _ => {}
        }

        match (s.pts, s.qts, s.seq, s.date) {
            (Some(pts), Some(qts), Some(seq), Some(date)) => session.set_state(UpdateState {
                pts,
                qts,
                seq,
                date,
                channels: HashMap::new(),
            }),
            _ => {}
        }

        match (s.dc_id, s.dc_addr.as_ref(), s.dc_port, s.dc_auth) {
            (Some(id), Some(addr), Some(port), Some(auth)) => {
                session.insert_dc(id, SocketAddr::new(addr.parse().unwrap(), port), auth)
            }
            _ => {}
        }
    }

    let client = Client::connect(Config {
        session,
        api_id: API_ID,
        api_hash: API_HASH.to_string(),
        params: InitParams {
            server_addr: if SERVER_ADDR.is_empty() {
                None
            } else {
                Some(SERVER_ADDR.parse().unwrap())
            },
            ..Default::default()
        },
    })
    .await
    .map_err(|_| NativeError::Network)?;

    info!("Connected!");

    CLIENT
        .set(client)
        .map_err(|_| NativeError::Initialization)?;

    Ok(())
}

async fn need_login() -> Result<bool> {
    let client = CLIENT.get().ok_or(NativeError::Initialization)?;
    client
        .is_authorized()
        .await
        .map_err(|_| NativeError::Network)
}

async fn request_login_code(phone: &str) -> Result<LoginToken> {
    let client = CLIENT.get().ok_or(NativeError::Initialization)?;
    client
        .request_login_code(&phone, API_ID, API_HASH)
        .await
        .map_err(|_| NativeError::Network)
}

async fn sign_in(token: LoginToken, code: &str) -> Result<()> {
    let client = CLIENT.get().ok_or(NativeError::Initialization)?;
    client
        .sign_in(&token, &code)
        .await
        .map_err(|_| NativeError::Network)?;

    let guard = DATABASE.lock().unwrap();
    let conn = match guard.as_ref() {
        Some(c) => c,
        None => {
            error!("Database was not initialized");
            return Err(NativeError::Initialization);
        }
    };

    let mut session = db::create_session(conn).map_err(|_| NativeError::Database)?;
    let s = client.session();
    if let Some(user) = s.get_user() {
        session.user_id = Some(user.id);
        session.dc_id = Some(user.dc);
        session.bot = Some(user.bot);
    }

    if let Some(state) = s.get_state() {
        session.pts = Some(state.pts);
        session.qts = Some(state.qts);
        session.seq = Some(state.seq);
        session.date = Some(state.date);
    }

    if let Some(dc_id) = session.dc_id {
        for dc in s.get_dcs() {
            if dc.id == dc_id {
                if let Some(ipv4) = dc.ipv4 {
                    session.dc_addr = Some(Ipv4Addr::from(ipv4.to_le_bytes()).to_string())
                } else if let Some(ipv6) = dc.ipv6 {
                    session.dc_addr = Some(Ipv6Addr::from(ipv6).to_string())
                }
                session.dc_port = Some(dc.port as u16);
                session.dc_auth = dc.auth.map(|b| b.try_into().unwrap());
                break;
            }
        }
    }

    db::update_session(conn, &session).map_err(|_| NativeError::Database)?;

    Ok(())
}

async fn get_dialogs() -> Result<Vec<OgDialog>> {
    let client = CLIENT.get().ok_or(NativeError::Initialization)?;

    let mut result = Vec::new();
    let mut dialogs = client.iter_dialogs();
    while let Some(dialog) = dialogs.next().await.map_err(|_| NativeError::Network)? {
        result.push(dialog);
    }
    Ok(result)
}

async fn send_message(chat: PackedChat, text: &str) -> Result<()> {
    let client = CLIENT.get().ok_or(NativeError::Initialization)?;
    client
        .send_message(chat, text)
        .await
        .map_err(|_| NativeError::Network)?;
    Ok(())
}

pub fn initDatabase(path: String) -> Result<()> {
    let mut guard = DATABASE.lock().unwrap();
    if guard.is_some() {
        info!("Database is already initialized");
    }

    match db::init_connection(&path) {
        Ok(conn) => {
            *guard = Some(conn);
            Ok(())
        }
        Err(e) => Err(NativeError::Database),
    }
}

pub fn initClient() -> Result<()> {
    block_on(init_client())
}

pub fn needLogin() -> Result<bool> {
    block_on(need_login())
}

pub fn requestLoginCode(phone: String) -> Result<u64> {
    block_on(request_login_code(&phone)).map(|token| Box::into_raw(Box::new(token)) as u64)
}

pub fn signIn(token_ptr: u64, code: String) -> Result<()> {
    let token = unsafe { *Box::from_raw(token_ptr as *mut LoginToken) };

    block_on(sign_in(token, &code))
}

pub fn getDialogs() -> Result<Vec<Dialog>> {
    block_on(get_dialogs()).map(|dialogs| {
        dialogs
            .into_iter()
            .map(|d| Dialog {
                id: d.chat().pack().to_hex(),
                title: d.chat().name().to_string(),
                lastMessage: d.last_message.map(|m| MessagePreview {
                    sender: if let Some(sender) = m.sender() {
                        sender.name().to_string()
                    } else {
                        "unknown".to_string()
                    },
                    text: m.text().to_string(),
                    date: m.date().into(),
                    ack: if m.outgoing() {
                        match &d.dialog {
                            tl::enums::Dialog::Dialog(d) => {
                                if m.id() <= d.read_inbox_max_id {
                                    MessageAck::Seen
                                } else {
                                    MessageAck::Sent
                                }
                            }
                            tl::enums::Dialog::Folder(_) => MessageAck::Received,
                        }
                    } else {
                        MessageAck::Received
                    },
                }),
                pinned: match d.dialog {
                    tl::enums::Dialog::Dialog(d) => d.pinned,
                    tl::enums::Dialog::Folder(f) => f.pinned,
                },
            })
            .collect()
    })
}

pub fn sendMessage(packed: String, text: String) -> Result<()> {
    let packed = PackedChat::from_hex(&packed).unwrap();
    block_on(send_message(packed, &text))
}