//! Attach mode — TUI-only client that connects to an existing daemon session
//! over a Unix socket, forwarding key events and rendering state updates.

use anyhow::Result;
use app::state::rest::AppStateRest;
use app::state::types::{Overlay, Toast, ToastKind};
use crossterm::execute;
use crossterm::terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen};
use ipc::protocol::{ClientRequest, DaemonFrame, StatePayload};
use ratatui::backend::CrosstermBackend;
use ratatui::Terminal;
use std::io;
use zesdex_cms::domain::repository::SettingsRepository;
use zesdex_utils::clipboard::write_osc52;

use crate::app;
use crate::daemon::key_code_to_action;
use crate::ipc;
use crate::model;
use crate::view;

/// Apply a `StatePayload` received from the daemon onto the client's
/// local `AppStateRest`, so the attach-mode TUI can render it.
///
/// Flow: copy scalar fields directly → rebuild the transcript cache from
/// `MessageEntry`s (mapping role strings back to the `Role` enum) →
/// resolve the overlay name string to an `Overlay` variant → rebuild
/// toasts from `ToastEntry`s.
///
/// Why: unrecognized role/overlay/toast-kind strings fall back to a safe
/// default (`Role::User`, `Overlay::None`, `ToastKind::Info`) rather than
/// panicking, so a protocol/version mismatch degrades gracefully.
fn apply_client_update(state: &mut AppStateRest, payload: StatePayload) {
    state.session_id = payload.session_id;
    state.dirty = payload.dirty;

    state.transcript_cache.messages = payload
        .messages
        .into_iter()
        .map(|m| app::state::rest::ChatMessageDisplay {
            role: match m.role.as_str() {
                "Assistant" => crate::dto::chat::message::Role::Assistant,
                "System" => crate::dto::chat::message::Role::System,
                "Tool" => crate::dto::chat::message::Role::Tool,
                _ => crate::dto::chat::message::Role::User,
            },
            content: m.content,
            timestamp: m.timestamp,
        })
        .collect();
    state.transcript_cache.dirty = true;

    state.misc.overlay = match payload.overlay.as_deref() {
        Some("Help") => Overlay::Help,
        Some("Settings") => Overlay::Settings,

        Some("Bash") => Overlay::Bash,
        Some("QuitConfirm") => Overlay::QuitConfirm,

        Some("KeyInput") => Overlay::KeyInput,
        Some("Editor") => Overlay::Editor,
        Some("Effort") => Overlay::Effort,
        Some("Mcp") => Overlay::Mcp,
        Some("Todo") => Overlay::Todo,
        Some("Rewind") => Overlay::Rewind,
        Some("Learning") => Overlay::Learning,
        Some("Usage") => Overlay::Usage,
        Some("Loading") => Overlay::Loading,
        Some("ModelSelector") => Overlay::ModelSelector,
        Some("ClearConfirm") => Overlay::ClearConfirm,

        _ => Overlay::None,
    };

    state.misc.toasts = payload
        .toasts
        .into_iter()
        .map(|t| Toast {
            kind: match t.kind.as_str() {
                "Success" => ToastKind::Success,
                "Warning" => ToastKind::Warning,
                "Error" => ToastKind::Error,
                "Lesson" => ToastKind::Lesson,
                _ => ToastKind::Info,
            },
            message: t.message,
            created_at: t.created_at,
            lifetime_ms: t.lifetime_ms,
        })
        .collect();

    state.input.buffer = payload.input_buffer;
    state.input.cursor = payload.input_cursor;
}

/// Set up the IPC client connection, terminal, and initial state for attach mode.
///
/// Flow: resolve socket path → connect → enable raw/alt mode → create state.
///
/// Return: (client, terminal, `client_state`) on success.
fn setup_attach_client(
    session_id: &str,
) -> Result<(
    ipc::client::IpcClient,
    Terminal<CrosstermBackend<io::Stdout>>,
    AppStateRest,
)> {
    let store = model::store::Store::new();
    let socket_path = store
        .base_dir
        .join("run")
        .join(format!("{session_id}.sock"));
    let addr = socket_path.to_string_lossy().to_string();
    let client = ipc::client::IpcClient::connect_unix(&addr)?;

    enable_raw_mode()?;
    let mut stdout = io::stdout();
    execute!(stdout, EnterAlternateScreen)?;
    execute!(stdout, crossterm::event::EnableBracketedPaste)?;
    execute!(stdout, crossterm::event::EnableMouseCapture)?;
    let backend = CrosstermBackend::new(stdout);
    let mut terminal = Terminal::new(backend)?;
    terminal.clear()?;

    let workspace_roots = vec![std::env::current_dir()?];
    let session_dir = store.base_dir.join("sessions").join(session_id);
    std::fs::create_dir_all(&session_dir)?;
    let mut client_state = AppStateRest::new(workspace_roots, &session_dir, store.memory_dir);
    client_state.session_id = session_id.to_string();

    Ok((client, terminal, client_state))
}

/// Process a single daemon frame from the IPC channel, updating state accordingly.
fn handle_daemon_frame(client_state: &mut AppStateRest, frame: Option<DaemonFrame>) {
    match frame {
        Some(DaemonFrame::StateUpdate(payload)) => {
            apply_client_update(client_state, *payload);
        }
        Some(DaemonFrame::StreamToken(_token)) => {}
        Some(DaemonFrame::SystemNote { kind: _, message }) => {
            client_state.push_toast(Toast::new(ToastKind::Info, message));
        }
        Some(DaemonFrame::ClipboardCopy(text)) => {
            let _ = write_osc52(&mut io::stdout(), &text);
            client_state.push_toast(Toast::new(
                ToastKind::Success,
                "Copied to clipboard".to_string(),
            ));
        }
        Some(DaemonFrame::Closed) | None => {
            client_state.quit = true;
        }
    }
}

/// Run zesdex as a TUI-only client attached to an existing daemon session.
///
/// Flow: connect to the daemon's Unix socket → enter raw mode/alternate
/// screen → build a local `AppStateRest` mirror (only used for rendering
/// and toast/overlay bookkeeping, not agent logic) → loop: poll for a
/// terminal event (key/resize) and forward it as a `ClientRequest`, or
/// send a `Tick` if idle → read the daemon's `DaemonFrame` reply and
/// apply it via `apply_client_update` → redraw → exit when the daemon
/// closes or the user quits (sending `ClientRequest::Close` first).
///
/// Why: Ctrl+C is intercepted locally to quit the client without going
/// through the daemon, since the daemon has no notion of "this client
/// wants to leave" beyond the explicit `Close` request.
pub fn run_attach(session_id: &str) -> Result<()> {
    use crossterm::event::{Event, KeyCode, KeyEventKind, KeyModifiers, MouseEventKind};

    let (client, mut terminal, mut client_state) = setup_attach_client(session_id)?;
    let _rt = tokio::runtime::Runtime::new()?;

    loop {
        if client_state.quit {
            let _ = client.send(&ClientRequest::Close);
            break;
        }

        let now_ms = chrono::Utc::now().timestamp_millis();
        client_state.misc.drain_expired_toasts(now_ms);

        if crossterm::event::poll(std::time::Duration::from_millis(50))? {
            match crossterm::event::read()? {
                Event::Key(key) => {
                    if key.kind == KeyEventKind::Press || key.kind == KeyEventKind::Repeat {
                        let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
                        let alt = key.modifiers.contains(KeyModifiers::ALT);
                        let shift = key.modifiers.contains(KeyModifiers::SHIFT);

                        if key.code == KeyCode::Char('c') && ctrl {
                            client_state.quit = true;
                            continue;
                        }

                        if let Some(key_action) = key_code_to_action(key.code) {
                            client.send(&ClientRequest::KeyPress {
                                key: key_action,
                                ctrl,
                                alt,
                                shift,
                            })?;
                        }
                    }
                }
                Event::Paste(text) => {
                    client.send(&ClientRequest::Paste(text))?;
                }
                Event::Resize(w, h) => {
                    client.send(&ClientRequest::Resize(w, h))?;
                }
                Event::Mouse(mouse_event) => {
                    if mouse_event.kind == MouseEventKind::ScrollUp {
                        client.send(&ClientRequest::ScrollUp)?;
                    } else if mouse_event.kind == MouseEventKind::ScrollDown {
                        client.send(&ClientRequest::ScrollDown)?;
                    }
                }
                _ => {}
            }
        } else {
            client.send(&ClientRequest::Tick)?;
        }

        handle_daemon_frame(
            &mut client_state,
            client.receive::<DaemonFrame>()?,
        );

        terminal.draw(|f| {
            view::draw(f, &client_state);
        })?;
    }

    let _ = execute!(io::stdout(), crossterm::event::DisableBracketedPaste);
    let _ = execute!(io::stdout(), crossterm::event::DisableMouseCapture);
    let _ = execute!(io::stdout(), LeaveAlternateScreen);
    let _ = disable_raw_mode();

    let _ = zesdex_cms::infrastructure::persistence::settings_repo::JsonSettingsRepository::new()
        .save(&client_state.store_base_dir(), &client_state.settings);

    Ok(())
}