feat: Add task scheduling and reminders system

Add comprehensive scheduling functionality with reminder notifications:

- Add scheduledDate, scheduledTime, and reminderMinutes fields to ImmerseTask
- Add enableReminders and defaultReminderMinutes to plugin settings
- Implement reminder notification system with 30-second background checks
- Add overdue task detection with visual indicators
- Add native HTML5 date/time pickers in Quick Add and Edit modals
- Add reminder dropdown with 5/10/15/30/60 minute options
- Display scheduled date/time with blue badge (📅) in task list
- Show pulsing red "OVERDUE" badge (⚠️) for past-due tasks
- Add red left border highlight for overdue tasks
- Implement startup check for due/overdue tasks when plugin loads
- Show overdue notices when Obsidian opens if tasks are past due
- Play alert sounds for reminders (if sounds enabled)
- Track shown reminders to prevent duplicate notifications

src/main.ts

@@ -44,10 +44,14 @@ export default class ImmersePlugin extends Plugin {
 	// Focus time tracking (in seconds for accuracy)
 	private focusSecondsToday: number = 0;
 	private secondsWorkedOnCurrentTask: number = 0;
-	
+
 	// Status bar element
 	statusBarEl: HTMLElement | null = null;
 
+	// Reminder system
+	private reminderCheckInterval: number | null = null;
+	private notifiedReminders: Set<string> = new Set(); // Track which reminders have been shown
+
 	async onload() {
 		await this.loadAllData();
 
@@ -108,10 +112,16 @@ export default class ImmersePlugin extends Plugin {
 
 		// Create status bar timer
 		this.createStatusBar();
+
+		// Start reminder checking system
+		if (this.settings.enableReminders) {
+			this.startReminderSystem();
+		}
 	}
 
 	onunload() {
 		this.stopTimer();
+		this.stopReminderSystem();
 	}
 
 	async loadAllData() {
@@ -604,6 +614,84 @@ export default class ImmersePlugin extends Plugin {
 		}
 	}
 
+	// ============ Reminder System ============
+
+	startReminderSystem() {
+		// Check for reminders every 30 seconds
+		this.reminderCheckInterval = window.setInterval(() => {
+			this.checkReminders();
+		}, 30000);
+		// Also check immediately
+		this.checkReminders();
+	}
+
+	stopReminderSystem() {
+		if (this.reminderCheckInterval) {
+			window.clearInterval(this.reminderCheckInterval);
+			this.reminderCheckInterval = null;
+		}
+	}
+
+	checkReminders() {
+		if (!this.settings.enableReminders) return;
+
+		const now = new Date();
+		const currentTime = now.getTime();
+
+		// Check each incomplete task with scheduling
+		this.data.tasks
+			.filter(task => !task.completed && task.scheduledDate && task.scheduledTime)
+			.forEach(task => {
+				const reminderKey = `${task.id}-${task.scheduledDate}-${task.scheduledTime}`;
+
+				// Skip if we already notified for this reminder
+				if (this.notifiedReminders.has(reminderKey)) return;
+
+				// Parse the scheduled date and time
+				const scheduledDateTime = new Date(`${task.scheduledDate}T${task.scheduledTime}`);
+				const scheduledTime = scheduledDateTime.getTime();
+
+				// Check for overdue tasks (scheduled time has passed)
+				if (currentTime > scheduledTime) {
+					this.showOverdueNotice(task);
+					this.notifiedReminders.add(reminderKey);
+					return;
+				}
+
+				// Check for tasks with reminders set
+				if (task.reminderMinutes) {
+					const reminderTime = scheduledTime - (task.reminderMinutes * 60 * 1000);
+
+					// Show reminder if it's past the reminder time but before the scheduled time
+					if (currentTime >= reminderTime) {
+						this.showReminder(task);
+						this.notifiedReminders.add(reminderKey);
+					}
+				}
+			});
+	}
+
+	showReminder(task: ImmerseTask) {
+		const timeStr = task.scheduledTime;
+		new Notice(`🔔 Reminder: "${task.text}" is scheduled for ${timeStr}`, 8000);
+
+		// Play alert sound if enabled
+		if (this.settings.enableSounds) {
+			this.playAlertSound();
+		}
+	}
+
+	showOverdueNotice(task: ImmerseTask) {
+		const dateStr = task.scheduledDate;
+		const timeStr = task.scheduledTime;
+		new Notice(`⚠️ Overdue: "${task.text}" was scheduled for ${dateStr} ${timeStr}`, 10000);
+
+		// Play alert sound if enabled
+		if (this.settings.enableSounds) {
+			this.playAlertSound();
+		}
+	}
+
 	// ============ Sounds & Celebrations ============
 
 	showCelebration(task: ImmerseTask) {

src/modals.ts

@@ -15,11 +15,15 @@ export class QuickAddTaskModal extends Modal {
 	taskText: string = '';
 	estimatedMinutes: number;
 	selectedList: string = 'work';
+	scheduledDate: string = '';
+	scheduledTime: string = '';
+	reminderMinutes: number = 0;
 
 	constructor(app: App, plugin: ImmersePlugin) {
 		super(app);
 		this.plugin = plugin;
 		this.estimatedMinutes = plugin.settings.defaultEstimateMinutes;
+		this.reminderMinutes = plugin.settings.defaultReminderMinutes;
 		if (plugin.settings.lists.length > 0) {
 			this.selectedList = plugin.settings.lists[0].id;
 		}
@@ -82,6 +86,45 @@ export class QuickAddTaskModal extends Modal {
 				dropdown.onChange(value => this.selectedList = value);
 			});
 
+		// Scheduled date
+		new Setting(contentEl)
+			.setName('📅 Scheduled Date')
+			.setDesc('Optional: When do you plan to work on this?')
+			.addText(text => {
+				text.setPlaceholder('YYYY-MM-DD')
+					.setValue(this.scheduledDate)
+					.onChange(value => this.scheduledDate = value);
+				text.inputEl.type = 'date';
+			});
+
+		// Scheduled time
+		new Setting(contentEl)
+			.setName('⏰ Scheduled Time')
+			.setDesc('Optional: What time?')
+			.addText(text => {
+				text.setPlaceholder('HH:mm')
+					.setValue(this.scheduledTime)
+					.onChange(value => this.scheduledTime = value);
+				text.inputEl.type = 'time';
+			});
+
+		// Reminder
+		if (this.plugin.settings.enableReminders) {
+			new Setting(contentEl)
+				.setName('🔔 Reminder')
+				.setDesc('Remind me before the scheduled time')
+				.addDropdown(dropdown => {
+					dropdown.addOption('0', 'No reminder');
+					dropdown.addOption('5', '5 minutes before');
+					dropdown.addOption('10', '10 minutes before');
+					dropdown.addOption('15', '15 minutes before');
+					dropdown.addOption('30', '30 minutes before');
+					dropdown.addOption('60', '1 hour before');
+					dropdown.setValue(this.reminderMinutes.toString());
+					dropdown.onChange(value => this.reminderMinutes = parseInt(value));
+				});
+		}
+
 		// Buttons
 		const buttonContainer = contentEl.createEl('div', { cls: 'immerse-modal-buttons' });
 		
@@ -95,6 +138,16 @@ export class QuickAddTaskModal extends Modal {
 	submitTask() {
 		if (this.taskText.trim()) {
 			const task = this.plugin.createTask(this.taskText, this.estimatedMinutes, this.selectedList);
+			// Add scheduling data if provided
+			if (this.scheduledDate) {
+				task.scheduledDate = this.scheduledDate;
+			}
+			if (this.scheduledTime) {
+				task.scheduledTime = this.scheduledTime;
+			}
+			if (this.reminderMinutes > 0 && this.scheduledDate && this.scheduledTime) {
+				task.reminderMinutes = this.reminderMinutes;
+			}
 			this.plugin.addTask(task);
 			new Notice('✅ Task added!');
 			this.close();
@@ -177,6 +230,48 @@ export class EditTaskModal extends Modal {
 				textarea.inputEl.rows = 4;
 			});
 
+		// Scheduled date
+		new Setting(contentEl)
+			.setName('📅 Scheduled Date')
+			.setDesc('Optional: When do you plan to work on this?')
+			.addText(text => {
+				text.setPlaceholder('YYYY-MM-DD')
+					.setValue(this.task.scheduledDate || '')
+					.onChange(value => this.task.scheduledDate = value || undefined);
+				text.inputEl.type = 'date';
+			});
+
+		// Scheduled time
+		new Setting(contentEl)
+			.setName('⏰ Scheduled Time')
+			.setDesc('Optional: What time?')
+			.addText(text => {
+				text.setPlaceholder('HH:mm')
+					.setValue(this.task.scheduledTime || '')
+					.onChange(value => this.task.scheduledTime = value || undefined);
+				text.inputEl.type = 'time';
+			});
+
+		// Reminder
+		if (this.plugin.settings.enableReminders) {
+			new Setting(contentEl)
+				.setName('🔔 Reminder')
+				.setDesc('Remind me before the scheduled time')
+				.addDropdown(dropdown => {
+					dropdown.addOption('0', 'No reminder');
+					dropdown.addOption('5', '5 minutes before');
+					dropdown.addOption('10', '10 minutes before');
+					dropdown.addOption('15', '15 minutes before');
+					dropdown.addOption('30', '30 minutes before');
+					dropdown.addOption('60', '1 hour before');
+					dropdown.setValue((this.task.reminderMinutes || 0).toString());
+					dropdown.onChange(value => {
+						const minutes = parseInt(value);
+						this.task.reminderMinutes = minutes > 0 ? minutes : undefined;
+					});
+				});
+		}
+
 		// Show actual time if task has been worked on
 		if (this.task.actualMinutes > 0) {
 			new Setting(contentEl)

src/types.ts

@@ -10,7 +10,9 @@ export interface ImmerseTask {
 	completedAt?: number;
 	list: string;
 	notes: string;
-	scheduledDate?: string;
+	scheduledDate?: string; // Date in YYYY-MM-DD format
+	scheduledTime?: string; // Time in HH:mm format (24-hour)
+	reminderMinutes?: number; // Minutes before scheduled time to remind (0 = no reminder)
 	isActive: boolean;
 }
 
@@ -34,6 +36,9 @@ export interface ImmerseSettings {
 	tickSoundEnabled: boolean;
 	// Daily note logging
 	logToDaily: boolean;
+	// Task reminders
+	enableReminders: boolean;
+	defaultReminderMinutes: number; // Default minutes before task to remind
 }
 
 export interface ImmerseData {
@@ -62,6 +67,9 @@ export const DEFAULT_SETTINGS: ImmerseSettings = {
 	tickSoundEnabled: false,
 	// Daily note logging
 	logToDaily: false,
+	// Task reminders
+	enableReminders: true,
+	defaultReminderMinutes: 15,
 };
 
 export const DEFAULT_DATA: ImmerseData = {

src/view.ts

@@ -326,9 +326,13 @@ export class ImmerseView extends ItemView {
 
 	renderTaskItem(container: Element, task: ImmerseTask) {
 		const list = this.plugin.settings.lists.find(l => l.id === task.list);
-		
-		const taskEl = container.createEl('div', { 
-			cls: `immerse-task-item ${task.completed ? 'completed' : ''} ${task.isActive ? 'active' : ''}` 
+
+		// Check if task is overdue
+		const isOverdue = !task.completed && task.scheduledDate && task.scheduledTime &&
+			new Date(`${task.scheduledDate}T${task.scheduledTime}`).getTime() < Date.now();
+
+		const taskEl = container.createEl('div', {
+			cls: `immerse-task-item ${task.completed ? 'completed' : ''} ${task.isActive ? 'active' : ''} ${isOverdue ? 'overdue' : ''}`
 		});
 		
 		// Checkbox
@@ -363,7 +367,7 @@ export class ImmerseView extends ItemView {
 		
 		const taskMeta = content.createEl('div', { cls: 'immerse-task-meta' });
 		taskMeta.createEl('span', { text: `Est: ${this.plugin.formatTimeHuman(task.estimatedMinutes)}` });
-		
+
 		if (task.actualMinutes > 0) {
 			const actualSpan = taskMeta.createEl('span');
 			actualSpan.setText(`Actual: ${this.plugin.formatTimeHuman(task.actualMinutes)}`);
@@ -372,6 +376,23 @@ export class ImmerseView extends ItemView {
 			}
 		}
 
+		// Show scheduled date/time if set
+		if (task.scheduledDate) {
+			const scheduleSpan = taskMeta.createEl('span', {
+				cls: `immerse-schedule-badge ${isOverdue ? 'overdue' : ''}`
+			});
+			const dateStr = task.scheduledDate;
+			const timeStr = task.scheduledTime || '';
+			if (isOverdue) {
+				scheduleSpan.setText(`⚠️ OVERDUE: ${dateStr}${timeStr ? ' ' + timeStr : ''}`);
+			} else {
+				scheduleSpan.setText(`📅 ${dateStr}${timeStr ? ' ' + timeStr : ''}`);
+			}
+			if (task.reminderMinutes) {
+				scheduleSpan.title = `Reminder set for ${task.reminderMinutes} min before`;
+			}
+		}
+
 		// Actions
 		const actions = taskEl.createEl('div', { cls: 'immerse-task-actions' });