// src/modes/handlers/mode_manager.rs
use crate::state::app::state::AppState;
use crate::modes::handlers::event::EventHandler;
use crate::state::pages::add_logic::AddLogicFocus;
use crate::state::pages::admin::AdminState;
use canvas::AppMode as CanvasMode;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum AppMode {
    General,   // For intro and admin screens
    ReadOnly,  // Canvas read-only mode
    Edit,      // Canvas edit mode
    Highlight, // Canvas highlight/visual mode
    Command,   // Command mode overlay
}

impl From<canvas::AppMode> for AppMode {
    fn from(mode: canvas::AppMode) -> Self {
        match mode {
            canvas::AppMode::General => AppMode::General,
            canvas::AppMode::ReadOnly => AppMode::ReadOnly,
            canvas::AppMode::Edit => AppMode::Edit,
            canvas::AppMode::Highlight => AppMode::Highlight,
            canvas::AppMode::Command => AppMode::Command,
        }
    }
}

pub struct ModeManager;

impl ModeManager {
    /// Determine current mode based on app state
    pub fn derive_mode(
        app_state: &AppState,
        event_handler: &EventHandler,
        admin_state: &AdminState,
    ) -> AppMode {
        // Navigation palette always forces General
        if event_handler.navigation_state.active {
            return AppMode::General;
        }

        // Explicit command mode flag
        if event_handler.command_mode {
            return AppMode::Command;
        }

        // ✅ Always trust the FormEditor when a form is active
        if let Some(editor) = &app_state.form_editor {
            return AppMode::from(editor.mode());
        }

        // --- Non-form views (add_logic, add_table, etc.) ---
        if app_state.ui.show_add_logic {
            match admin_state.add_logic_state.current_focus {
                AddLogicFocus::InputLogicName
                | AddLogicFocus::InputTargetColumn
                | AddLogicFocus::InputDescription => {
                    if event_handler.is_edit_mode {
                        AppMode::Edit
                    } else {
                        AppMode::ReadOnly
                    }
                }
                _ => AppMode::General,
            }
        } else if app_state.ui.show_add_table {
            if app_state.ui.focus_outside_canvas {
                AppMode::General
            } else if event_handler.is_edit_mode {
                AppMode::Edit
            } else {
                AppMode::ReadOnly
            }
        } else if app_state.ui.show_login
            || app_state.ui.show_register
        {
            // login/register still use the old flag
            if event_handler.is_edit_mode {
                AppMode::Edit
            } else {
                AppMode::ReadOnly
            }
        } else {
            AppMode::General
        }
    }

    // Mode transition rules
    pub fn can_enter_command_mode(current_mode: AppMode) -> bool {
        !matches!(current_mode, AppMode::Edit)
    }

    pub fn can_enter_edit_mode(current_mode: AppMode) -> bool {
        matches!(current_mode, AppMode::ReadOnly)
    }

    pub fn can_enter_read_only_mode(current_mode: AppMode) -> bool {
        matches!(
            current_mode,
            AppMode::Edit | AppMode::Command | AppMode::Highlight
        )
    }

    pub fn can_enter_highlight_mode(current_mode: AppMode) -> bool {
        matches!(current_mode, AppMode::ReadOnly)
    }
}