/**
 * GoingsOn - Application State
 * Centralized state management with pub/sub for reactivity
 */

(function() {
'use strict';

// ============ State Class ============

class AppStateManager {
    constructor() {
        // Subscribers for state changes
        this._subscribers = {};

        // ============ Data State (single source of truth) ============

        // Domain data
        this.projects = [];
        this.tasks = [];
        this.emails = [];
        this.emailAccounts = [];

        // ============ UI State ============

        // Current view/selection
        this.currentView = 'projects';
        this.currentProjectId = null;

        // Day planning
        this.dayPlanDate = new Date();
        this.dayPlanData = null;

        // Drag and drop
        this.draggedTaskId = null;

        // Timeline
        this.currentTimeIndicatorInterval = null;
        this.paintingState = null; // { startSlot, startTime, endSlot, endTime, preview }

        // Keyboard navigation
        this.pendingKey = null;
        this.pendingKeyTimeout = null;
        this.selectedItemIndex = -1;

        // Bulk selection (keeping as Sets for performance)
        this.selectedTaskIds = new Set();
        this.selectedEmailIds = new Set();

        // Pagination
        this.taskPage = 1;
        this.emailPage = 1;
        this.itemsPerPage = 50;

        // View switch tracking (in-memory only, reset on restart)
        this.viewSwitchCounts = {};
        this.lastSubviewByTab = {};
        this.sessionStart = Date.now();
    }

    /**
     * Set a state property and notify subscribers
     * @param {string} key - Property name
     * @param {*} value - New value
     */
    set(key, value) {
        const oldValue = this[key];
        this[key] = value;
        this.notify(key, value, oldValue);
    }

    /**
     * Subscribe to changes on a state property
     * @param {string} key - Property name to watch
     * @param {Function} callback - Called with (newValue, oldValue)
     * @returns {Function} Unsubscribe function
     */
    subscribe(key, callback) {
        if (!this._subscribers[key]) {
            this._subscribers[key] = [];
        }
        this._subscribers[key].push(callback);

        // Return unsubscribe function
        return () => {
            const idx = this._subscribers[key].indexOf(callback);
            if (idx > -1) {
                this._subscribers[key].splice(idx, 1);
            }
        };
    }

    /**
     * Notify all subscribers of a state change
     * @param {string} key - Property that changed
     * @param {*} newValue - New value
     * @param {*} oldValue - Previous value
     */
    notify(key, newValue, oldValue) {
        const callbacks = this._subscribers[key];
        if (callbacks) {
            for (const cb of callbacks) {
                try {
                    cb(newValue, oldValue);
                } catch (err) {
                    console.error(`State subscriber error for "${key}":`, err);
                }
            }
        }
    }

    /**
     * Batch update multiple properties
     * @param {Object} updates - Object with key-value pairs to update
     */
    update(updates) {
        for (const [key, value] of Object.entries(updates)) {
            this.set(key, value);
        }
    }

    /**
     * Reset pagination for a domain
     * @param {string} domain - 'task' or 'email'
     */
    resetPagination(domain) {
        if (domain === 'task') {
            this.set('taskPage', 1);
        } else if (domain === 'email') {
            this.set('emailPage', 1);
        }
    }

    /**
     * Clear selection for a domain
     * @param {string} domain - 'task' or 'email'
     */
    clearSelection(domain) {
        if (domain === 'task') {
            this.selectedTaskIds.clear();
            this.notify('selectedTaskIds', this.selectedTaskIds, null);
        } else if (domain === 'email') {
            this.selectedEmailIds.clear();
            this.notify('selectedEmailIds', this.selectedEmailIds, null);
        }
    }
}

// ============ Create Global Instance ============

const AppState = new AppStateManager();

// ============ Populate GoingsOn.state ============

GoingsOn.state = AppState;

})();