// src/pages/admin_panel/add_logic/event.rs

use anyhow::Result;
use crate::config::binds::config::Config;
use crate::movement::{move_focus, MovementAction};
use crate::pages::admin_panel::add_logic::nav::SaveLogicResultSender;
use crate::pages::admin_panel::add_logic::state::{AddLogicFocus, AddLogicFormState};
use crate::components::common::text_editor::TextEditor;
use crate::services::grpc_client::GrpcClient;
use crate::state::app::state::AppState;
use crate::modes::handlers::event::EventOutcome;
use canvas::{AppMode as CanvasMode, DataProvider};
use crossterm::event::KeyEvent;

/// Focus traversal order for non-canvas navigation
const ADD_LOGIC_FOCUS_ORDER: [AddLogicFocus; 6] = [
    AddLogicFocus::InputLogicName,
    AddLogicFocus::InputTargetColumn,
    AddLogicFocus::InputDescription,
    AddLogicFocus::ScriptContentPreview,
    AddLogicFocus::SaveButton,
    AddLogicFocus::CancelButton,
];

/// Handles all AddLogic page-specific events.
/// Return a non-empty Ok(message) only when the page actually consumed the key,
/// otherwise return Ok("") to let global handling proceed.
pub fn handle_add_logic_event(
    key_event: KeyEvent,
    movement: Option<MovementAction>,
    config: &Config,
    app_state: &mut AppState,
    add_logic_page: &mut AddLogicFormState,
    grpc_client: GrpcClient,
    save_logic_sender: SaveLogicResultSender,
) -> Result<EventOutcome> {
    // 1) Script editor fullscreen mode
    if add_logic_page.state.current_focus == AddLogicFocus::InsideScriptContent {
        match key_event.code {
            crossterm::event::KeyCode::Esc => {
                add_logic_page.state.current_focus = AddLogicFocus::ScriptContentPreview;
                add_logic_page.focus_outside_canvas = true;
                return Ok(EventOutcome::Ok("Exited script editing.".to_string()));
            }
            _ => {
                let changed = {
                    let mut editor_borrow =
                        add_logic_page.state.script_content_editor.borrow_mut();
                    TextEditor::handle_input(
                        &mut editor_borrow,
                        key_event,
                        &add_logic_page.state.editor_keybinding_mode,
                        &mut add_logic_page.state.vim_state,
                    )
                };
                if changed {
                    add_logic_page.state.has_unsaved_changes = true;
                    return Ok(EventOutcome::Ok("Script updated".to_string()));
                }
                return Ok(EventOutcome::Ok(String::new()));
            }
        }
    }

    // 2) Inside canvas: forward to FormEditor
    let inside_canvas_inputs = matches!(
        add_logic_page.state.current_focus,
        AddLogicFocus::InputLogicName
            | AddLogicFocus::InputTargetColumn
            | AddLogicFocus::InputDescription
    );

    if inside_canvas_inputs {
        // Only allow leaving the canvas with Down/Next when the form editor
        // is in ReadOnly mode. In Edit mode, keep focus inside the canvas.
        let in_edit_mode = add_logic_page.editor.mode() == CanvasMode::Edit;
        if !in_edit_mode {
            if let Some(ma) = movement {
                let last_idx = add_logic_page
                    .editor
                    .data_provider()
                    .field_count()
                    .saturating_sub(1);
                let at_last = add_logic_page.editor.current_field() >= last_idx;
                if at_last && matches!(ma, MovementAction::Down | MovementAction::Next) {
                    add_logic_page.state.last_canvas_field = last_idx;
                    add_logic_page.state.current_focus = AddLogicFocus::ScriptContentPreview;
                    add_logic_page.focus_outside_canvas = true;
                    return Ok(EventOutcome::Ok("Moved to Script Preview".to_string()));
                }
            }
        }

        match add_logic_page.handle_key_event(key_event) {
            canvas::keymap::KeyEventOutcome::Consumed(Some(msg)) => {
                add_logic_page.sync_from_editor();
                return Ok(EventOutcome::Ok(msg));
            }
            canvas::keymap::KeyEventOutcome::Consumed(None) => {
                add_logic_page.sync_from_editor();
                return Ok(EventOutcome::Ok("Input updated".into()));
            }
            canvas::keymap::KeyEventOutcome::Pending => {
                return Ok(EventOutcome::Ok(String::new()));
            }
            canvas::keymap::KeyEventOutcome::NotMatched => {
                // fall through
            }
        }
    }

    // 3) Outside canvas
    if let Some(ma) = movement {
        let mut current = add_logic_page.state.current_focus;
        if move_focus(&ADD_LOGIC_FOCUS_ORDER, &mut current, ma) {
            add_logic_page.state.current_focus = current;
            add_logic_page.focus_outside_canvas = !matches!(
                add_logic_page.state.current_focus,
                AddLogicFocus::InputLogicName
                    | AddLogicFocus::InputTargetColumn
                    | AddLogicFocus::InputDescription
            );
            return Ok(EventOutcome::Ok(String::new()));
        }

        match ma {
            MovementAction::Select => match add_logic_page.state.current_focus {
                AddLogicFocus::ScriptContentPreview => {
                    add_logic_page.state.current_focus = AddLogicFocus::InsideScriptContent;
                    add_logic_page.focus_outside_canvas = false;
                    return Ok(EventOutcome::Ok(
                        "Fullscreen script editing. Esc to exit.".to_string(),
                    ));
                }
                AddLogicFocus::SaveButton => {
                    if let Some(msg) = add_logic_page.state.save_logic() {
                        return Ok(EventOutcome::Ok(msg));
                    } else {
                        return Ok(EventOutcome::Ok("Saved (no changes)".to_string()));
                    }
                }
                AddLogicFocus::CancelButton => {
                    return Ok(EventOutcome::Ok("Cancelled Add Logic".to_string()));
                }
                _ => {}
            },
            MovementAction::Esc => {
                if add_logic_page.state.current_focus == AddLogicFocus::ScriptContentPreview {
                    add_logic_page.state.current_focus = AddLogicFocus::InputDescription;
                    add_logic_page.focus_outside_canvas = false;
                    return Ok(EventOutcome::Ok("Back to Description".to_string()));
                }
            }
            _ => {}
        }
    }

    Ok(EventOutcome::Ok(String::new()))
}