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

mod db;

use grammers_client::types::{LoginToken, Message as OgMessage};
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 {}

struct LoginProcedure {
    token: Mutex<Option<LoginToken>>,
}

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

#[derive(Debug, Clone, Copy)]
pub enum Formatting {
    Unknown,
    Mention,
    HashTag,
    BotCommand,
    Url,
    Email,
    Bold,
    Italic,
    Code,
    Pre,
    TextUrl,
    MentionName,
    Phone,
    CashTag,
    Underline,
    Strike,
    Blockquote,
    BankCard,
    Spoiler,
    CustomEmoji,
}

#[derive(Debug, Clone)]
pub struct TextFormat {
    format: Formatting,
    offset: i32,
    length: i32,
    extra: Option<String>,
}

#[derive(Debug, Clone)]
pub struct Message {
    id: i32,
    sender: String,
    text: String,
    date: SystemTime,
    edit_date: Option<SystemTime>,
    formatting: Vec<TextFormat>,
}

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

#[derive(Debug, Clone)]
pub struct Dialog {
    id: String,
    title: String,
    last_message: 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)
}

pub fn init_database(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(_) => Err(NativeError::Database),
    }
}

pub 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 = block_on(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()
        },
    }))
    .map_err(|_| NativeError::Network)?;

    info!("Connected!");

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

    Ok(())
}

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

impl LoginProcedure {
    fn new() -> Self {
        Self {
            token: Mutex::new(None),
        }
    }

    fn request_login_code(&self, phone: String) -> Result<()> {
        let client = CLIENT.get().ok_or(NativeError::Initialization)?;
        let token = block_on(client.request_login_code(&phone, API_ID, API_HASH))
            .map_err(|_| NativeError::Network)?;
        *self.token.lock().unwrap() = Some(token);
        Ok(())
    }

    fn sign_in(&self, code: String) -> Result<()> {
        let token = self
            .token
            .lock()
            .unwrap()
            .take()
            .ok_or(NativeError::Initialization)?;
        let client = CLIENT.get().ok_or(NativeError::Initialization)?;

        block_on(client.sign_in(&token, &code)).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(())
    }
}

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

    block_on(async {
        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)
    })
    .map(|dialogs| {
        dialogs
            .into_iter()
            .map(|d| Dialog {
                id: d.chat().pack().to_hex(),
                title: d.chat().name().to_string(),
                last_message: 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()
    })
}

fn adapt_message(m: OgMessage) -> Message {
    Message {
        id: m.id(),
        sender: if let Some(sender) = m.sender() {
            sender.name().to_string()
        } else {
            "unknown".to_string()
        },
        text: m.text().to_string(),
        date: m.date().into(),
        edit_date: m.edit_date().map(|d| d.into()),
        formatting: if let Some(entities) = m.fmt_entities() {
            use tl::enums::MessageEntity as ME;

            macro_rules! tf {
                ($formatting:ident($entity:ident)) => {
                    tf!($formatting($entity).extra(None))
                };
                ($formatting:ident($entity:ident).extra($extra:expr)) => {
                    TextFormat {
                        format: Formatting::$formatting,
                        offset: $entity.offset,
                        length: $entity.length,
                        extra: $extra,
                    }
                };
            }

            entities
                .into_iter()
                .map(|e| match e {
                    ME::Unknown(e) => tf!(Unknown(e)),
                    ME::Mention(e) => tf!(Mention(e)),
                    ME::Hashtag(e) => tf!(HashTag(e)),
                    ME::BotCommand(e) => tf!(BotCommand(e)),
                    ME::Url(e) => tf!(Url(e)),
                    ME::Email(e) => tf!(Email(e)),
                    ME::Bold(e) => tf!(Bold(e)),
                    ME::Italic(e) => tf!(Italic(e)),
                    ME::Code(e) => tf!(Code(e)),
                    ME::Pre(e) => tf!(Pre(e).extra(Some(e.language.to_string()))),
                    ME::TextUrl(e) => tf!(TextUrl(e).extra(Some(e.url.to_string()))),
                    ME::MentionName(e) => tf!(MentionName(e).extra(Some(e.user_id.to_string()))),
                    ME::InputMessageEntityMentionName(e) => tf!(Unknown(e)),
                    ME::Phone(e) => tf!(Phone(e)),
                    ME::Cashtag(e) => tf!(CashTag(e)),
                    ME::Underline(e) => tf!(Underline(e)),
                    ME::Strike(e) => tf!(Strike(e)),
                    ME::Blockquote(e) => tf!(Blockquote(e)),
                    ME::BankCard(e) => tf!(BankCard(e)),
                    ME::Spoiler(e) => tf!(Spoiler(e)),
                    ME::CustomEmoji(e) => {
                        tf!(CustomEmoji(e).extra(Some(e.document_id.to_string())))
                    }
                })
                .collect()
        } else {
            Vec::new()
        },
    }
}

pub fn get_messages(packed: String) -> Result<Vec<Message>> {
    let chat = PackedChat::from_hex(&packed).unwrap();
    let client = CLIENT.get().ok_or(NativeError::Initialization)?;

    block_on(async {
        let mut result = Vec::new();
        let mut messages = client.iter_messages(chat);
        while let Some(message) = messages.next().await.map_err(|_| NativeError::Network)? {
            result.push(message);
        }
        Ok(result)
    })
    .map(|messages| messages.into_iter().map(adapt_message).collect())
}

pub fn send_message(packed: String, text: String) -> Result<Message> {
    let chat = PackedChat::from_hex(&packed).unwrap();
    let client = CLIENT.get().ok_or(NativeError::Initialization)?;
    block_on(client.send_message(chat, text))
        .map(adapt_message)
        .map_err(|_| NativeError::Network)
}