As a User, I want to register using my email/mobile and password, so that I can securely access my expense data.

• Email/Mobile must be unique
• Password must satisfy minimum strength rules
• Mandatory fields missing হলে registration complete হবে না

As a User, I want to log in securely, so that I can manage my expenses and budgets.

• Wrong credentials → generic error message
• Multiple failed attempts → optional lock/delay (security)

As a User, I want to recover my password, so that I don’t lose access to my data.

• OTP / email verification required
• Reset token time-bound

As a User, I want to create expense category, so that I can organize my expenses and budgets according to my specific needs, and these categories will be available for selection during budget planning and expense entry.

Acceptance Criteria:

• Category name must be unique (case-insensitive validation)
• Category name cannot be empty or contain only whitespace
• Successfully created categories are marked as "Active" by default
• User receives confirmation message upon successful category creation
• Appropriate error messages are displayed for validation failures
• Maximum character limit for category name is defined (e.g., 50 characters)

As a User, I want to deactivate or reactivate expense categories (by selecting one from the list, see US-6), so that I can control which categories are available for new expense entries and budget planning while preserving historical data integrity.

Acceptance Criteria:

• Deactivated categories are hidden from selection lists during new expense entry and budget planning
• Deactivated categories remain visible in historical reports and existing expenses
• Existing expenses associated with a deactivated category retain their category assignment
• User can reactivate a previously deactivated category
• The system displays a confirmation prompt before deactivating a category
• Category status (Active/Inactive) is clearly indicated in the category list
• Deactivation does not delete the category or associated data

As a User, I want to view a comprehensive list of all categories with their current status, so that I can efficiently manage my category structure by updating names, activating, or deactivating categories as needed.

Acceptance Criteria:

• Display all categories in a list/table format with columns for: Category Name, Status (Active/Inactive), and Action (Edit)
• Provide search/filter functionality to find specific categories
• Category name uniqueness validation applies during updates
• Sort categories alphabetically or by status
• Changes are saved with appropriate confirmation messages

As a User, I want to record an expense with date, amount, and category.

• Amount must be positive
• Date cannot be in the future
• Category is mandatory

As a User, I want to be warned if I accidentally enter the same expense twice.

• Same Date + Amount + Category + Description → show warning (not block)

As a User, I want to edit or delete expenses if I made a mistake.

• Current year expenses → editable
• Previous year expenses → restricted / approval required (optional)

As a User, I want to define my budget for a year, so that I can control spending.

• Budget amount must be positive
• Only one budget per year per category
• Budget not set → treated as Unlimited

As a User, I want to be notified when my spending crosses 50%, 80%, or 100% of my budget.

• Thresholds configurable (50/80/100 default)
• Each threshold triggers only once per cycle (anti-spam)