flowchart TD
    subgraph "Event Configuration"
        EVENT[Event] --> CAPACITY[Max Capacity]
        EVENT --> DURATION[Duration]
        EVENT --> BUFFER[Buffer Time]
        EVENT --> RECURRENCE[Recurrence Pattern]
    end

    subgraph "Occurrence Generation"
        RECURRENCE --> GENERATE[Generate Occurrences]
        GENERATE --> SLOTS[Time Slots]
        SLOTS --> AVAILABLE[Available Spots]
    end

    subgraph "Booking Impact"
        BOOKING[New Booking] --> DECREMENT[Decrement Available]
        CANCEL[Cancellation] --> INCREMENT[Increment Available]
    end

    AVAILABLE --> CHECK{Spots > 0?}
    CHECK -->|Yes| OPEN[Open for Booking]
    CHECK -->|No| FULL[Show Full/Waitlist]

flowchart TD
    PATTERN[Recurrence Pattern] --> TYPE{Type}

    TYPE --> DAILY[Daily]
    TYPE --> WEEKLY[Weekly]
    TYPE --> MONTHLY[Monthly]
    TYPE --> CUSTOM[Custom]

    subgraph "Weekly Options"
        WEEKLY --> DAYS[Select Days]
        DAYS --> MON[Monday]
        DAYS --> TUE[Tuesday]
        DAYS --> WED[Wednesday]
        DAYS --> THU[Thursday]
        DAYS --> FRI[Friday]
        DAYS --> SAT[Saturday]
        DAYS --> SUN[Sunday]
    end

    subgraph "Monthly Options"
        MONTHLY --> MTYPE{Monthly Type}
        MTYPE --> DOM[Day of Month]
        MTYPE --> DOW[Day of Week]

        DOM --> D1[1st, 15th, etc.]
        DOW --> D2[First Monday, etc.]
    end

    subgraph "Limits"
        PATTERN --> END{End Condition}
        END --> DATE[Until Date]
        END --> COUNT[After N Occurrences]
        END --> NEVER[No End]
    end

sequenceDiagram
    participant Admin
    participant UI as Event UI
    participant API as TRPC Router
    participant Service as Event Service
    participant DB as Database

    Admin->>UI: Create recurring event
    UI->>API: createEvent(eventData, recurrence)
    API->>Service: createEventWithRecurrence(data)

    Service->>Service: Parse recurrence rule
    Service->>Service: Calculate occurrences

    loop For each occurrence
        Service->>DB: Create EventOccurrence
        Note over Service: startTime, endTime, availableSpots
    end

    Service->>DB: Save event with recurrence rule
    DB-->>Service: Event created

    Service-->>API: Event + occurrences
    API-->>UI: Show calendar view

flowchart TD
    REQUEST[Check Availability] --> GET[Get Occurrence]
    GET --> CALC[Calculate Available]

    CALC --> CAPACITY[Event Capacity]
    CALC --> BOOKED[Confirmed Bookings]
    CALC --> HELD[Held/Pending]

    CAPACITY --> FORMULA[Available = Capacity - Booked - Held]
    BOOKED --> FORMULA
    HELD --> FORMULA

    FORMULA --> RESULT{Available > 0?}

    RESULT -->|Yes| AVAILABLE[Spots Available]
    RESULT -->|No| CHECK_WL{Waitlist Enabled?}

    CHECK_WL -->|Yes| WAITLIST[Show Waitlist Option]
    CHECK_WL -->|No| FULL[Show Full]

    AVAILABLE --> DISPLAY[Display Available Count]

    style AVAILABLE fill:#e8f5e9
    style FULL fill:#ffebee

flowchart TD
    INSTRUCTOR[Instructor] --> SCHEDULE[Working Schedule]
    SCHEDULE --> REGULAR[Regular Hours]
    SCHEDULE --> EXCEPTIONS[Exceptions]

    REGULAR --> DAYS[Available Days]
    REGULAR --> HOURS[Working Hours]

    EXCEPTIONS --> VACATION[Vacation/Leave]
    EXCEPTIONS --> SPECIAL[Special Availability]

    subgraph "Conflict Detection"
        EVENT[Schedule Event] --> CHECK[Check Instructor Availability]
        CHECK --> CONFLICTS{Conflicts?}
        CONFLICTS -->|Yes| ALERT[Show Conflict Alert]
        CONFLICTS -->|No| ALLOW[Allow Scheduling]
    end

flowchart TD
    REQUEST[Calendar Request] --> PARAMS[Parameters]

    PARAMS --> DATE_RANGE[Date Range]
    PARAMS --> FILTERS[Filters]

    DATE_RANGE --> START[Start Date]
    DATE_RANGE --> END[End Date]

    FILTERS --> CATEGORY[Category]
    FILTERS --> INSTRUCTOR[Instructor]
    FILTERS --> LOCATION[Location]

    subgraph "Data Aggregation"
        START --> QUERY[Query Occurrences]
        END --> QUERY
        CATEGORY --> QUERY
        INSTRUCTOR --> QUERY
        LOCATION --> QUERY

        QUERY --> OCCURRENCES[Event Occurrences]
        OCCURRENCES --> ENRICH[Enrich with Booking Data]
        ENRICH --> FORMAT[Format for Calendar]
    end

    FORMAT --> RESPONSE[Calendar Data]

flowchart TD
    subgraph "Overbooking Prevention"
        BOOK[Booking Request] --> LOCK[Lock Occurrence]
        LOCK --> CHECK[Check Availability]
        CHECK --> AVAILABLE{Available?}
        AVAILABLE -->|Yes| CONFIRM[Create Booking]
        AVAILABLE -->|No| REJECT[Reject/Waitlist]
        CONFIRM --> UNLOCK[Unlock Occurrence]
        REJECT --> UNLOCK
    end

    subgraph "Capacity Change"
        CHANGE[Change Capacity] --> COMPARE{New < Current?}
        COMPARE -->|Yes| OVERBOOKED[Check for Overbooking]
        COMPARE -->|No| APPLY[Apply Change]

        OVERBOOKED --> RESOLVE{Resolve?}
        RESOLVE --> NOTIFY[Notify Affected]
        RESOLVE --> CANCEL[Cancel Excess]
        RESOLVE --> KEEP[Keep (Allow Overbook)]
    end

erDiagram
    EVENT ||--o{ EVENT_OCCURRENCE : scheduled_as
    EVENT_OCCURRENCE ||--o{ EVENT_BOOKING : has
    INSTRUCTOR ||--o{ INSTRUCTOR_AVAILABILITY : has
    LOCATION ||--o{ LOCATION_AVAILABILITY : has

    EVENT_OCCURRENCE {
        string id PK
        string eventId FK
        timestamp startTime
        timestamp endTime
        int capacity
        int availableSpots
        enum status
        string locationId FK
        string instructorId FK
    }

    INSTRUCTOR_AVAILABILITY {
        string id PK
        string instructorId FK
        enum dayOfWeek
        time startTime
        time endTime
        boolean isAvailable
    }

    LOCATION_AVAILABILITY {
        string id PK
        string locationId FK
        timestamp startTime
        timestamp endTime
        boolean isBlocked
        string reason
    }

sequenceDiagram
    participant User1 as User 1
    participant User2 as User 2
    participant UI as UI (WebSocket)
    participant Server as Server
    participant DB as Database

    Note over User1,User2: Both viewing same event

    User1->>Server: Book last spot
    Server->>DB: Create booking
    DB-->>Server: Success

    Server->>Server: Update availability
    Server->>UI: Broadcast: spots = 0

    UI->>User1: "Booking confirmed"
    UI->>User2: "Event now full"

    Note over User2: Cannot book, sees waitlist option

flowchart TD
    NEW_EVENT[New Event/Occurrence] --> CHECK_ALL[Check Conflicts]

    CHECK_ALL --> INSTRUCTOR_CONFLICT[Instructor Conflicts]
    CHECK_ALL --> LOCATION_CONFLICT[Location Conflicts]
    CHECK_ALL --> ATTENDEE_CONFLICT[Attendee Conflicts]

    INSTRUCTOR_CONFLICT --> I_RESULT{Conflict?}
    I_RESULT -->|Yes| I_ALERT[Instructor Double-Booked]
    I_RESULT -->|No| CONTINUE1[Continue]

    LOCATION_CONFLICT --> L_RESULT{Conflict?}
    L_RESULT -->|Yes| L_ALERT[Location Double-Booked]
    L_RESULT -->|No| CONTINUE2[Continue]

    CONTINUE1 --> FINAL
    CONTINUE2 --> FINAL
    I_ALERT --> RESOLVE
    L_ALERT --> RESOLVE

    FINAL{All Clear?} -->|Yes| CREATE[Create Event]
    RESOLVE[Resolve Conflict] --> CHECK_ALL

    style CREATE fill:#e8f5e9