erDiagram
    %% --- MAIN DOCUMENTS ---
    sale_quotations {
        bigint id PK
        string quotation_number
        enum quotation_type "CASH_SALE, LEASE_SALE"
        date quotation_date
        date valid_until
        foreignId branch_id FK
        string customer_name
        decimal grand_total
        enum quotation_status "DRAFT, PENDING, APPROVED, CONVERTED..."
        timestamp created_at
    }

    sale_quotation_items {
        bigint id PK
        foreignId quotation_id FK
        foreignId item_variant_id FK
        decimal quoted_qty
        foreignId quoted_unit_id FK
        decimal unit_price
        decimal line_total
    }

    sale_bookings {
        bigint id PK
        string booking_number
        enum booking_type "CASH_SALE, LEASE_SALE"
        enum reference_type "SALE_QUOTATION, DEFAULT"
        bigint reference_id "Nullable FK to Quotation"
        date booking_date
        foreignId branch_id FK
        string customer_name
        decimal total_amount
        enum booking_status "DRAFT, APPROVED, CONVERTED..."
        timestamp created_at
    }

    sale_booking_items {
        bigint id PK
        foreignId booking_id FK
        foreignId item_variant_id FK
        decimal booking_qty
        foreignId booking_unit_id FK
        decimal unit_price
        decimal line_total
    }

    %% --- CONFIGURATION & MASTER DATA ---
    customer_groups {
        bigint id PK
        string group_name
        text description
        boolean is_active
    }

    item_cash_sale_prices {
        bigint id PK
        foreignId item_variant_id FK
        foreignId branch_id FK
        string price_list_code
        decimal salesman_price
        decimal retail_price
        decimal fixed_price
        enum default_price_type "salesman, retail, fixed"
        boolean change_price
        datetime effective_date
    }

    item_plans {
        bigint id PK
        foreignId item_variant_id FK
        foreignId branch_id FK
        string item_plan_code
        string name
        decimal installment_price
        decimal installment_advance
        integer duration_months
        decimal monthly_installment
        boolean is_active
    }

    %% --- RELATIONSHIPS ---
    sale_quotations ||--o{ sale_quotation_items : "contains"
    sale_bookings   ||--o{ sale_booking_items : "contains"
    
    sale_quotations ||--o| sale_bookings : "converts to"
    
    %% Implicit Relationships (Master Data usage)
    item_cash_sale_prices ||--o{ sale_quotation_items : "provides rate for Cash Sale"
    item_cash_sale_prices ||--o{ sale_booking_items : "provides rate for Cash Sale"
    
    item_plans ||--o{ sale_quotation_items : "provides terms for Lease Sale"
    item_plans ||--o{ sale_booking_items : "provides terms for Lease Sale"

    %% Grouping (Logical)
    customer_groups }|..|{ sale_quotations : "can apply discount rules"
                            

sequenceDiagram
    autonumber
    actor Sales as Sales Officer
    participant GUI as Livewire
(CreateQuotation)
    participant Svc as PreSaleService
    participant Repo as QuotationRepository
    participant BKRepo as BookingRepository
    participant Appr as ApprovalEngine
    participant DB as Database

    Sales->>GUI: Create Quotation
    GUI->>Svc: create(data)
    
    activate Svc
    Svc->>Repo: create(data)
    
    Svc->>Appr: checkSetupExists('CREATE', SaleQuotation::class)
    alt Approval Needed
        Svc->>Repo: updateStatus(PENDING)
    else Auto Approved
        Svc->>Repo: updateStatus(APPROVED)
    end
    
    Svc-->>GUI: Quotation Created
    deactivate Svc

    Sales->>GUI: Convert to Booking
    GUI->>Svc: convertToBooking(quotation_id)
    
    activate Svc
    Svc->>DB: Begin Transaction
    Svc->>Repo: find(quotation_id)
    Svc->>BKRepo: create(from_quotation_data)
    Svc->>Repo: updateStatus(CONVERTED)
    Svc->>DB: Commit Transaction
    Svc-->>GUI: Booking Created
    deactivate Svc
                            

stateDiagram-v2
    state Quotation {
        [*] --> Draft_Q : Created
        Draft_Q --> Pending_Q : Submitted
        Pending_Q --> Approved_Q : Manager Approves
        Pending_Q --> Rejected_Q : Manager Rejects
        Approved_Q --> Converted : Booking Created
        Approved_Q --> Cancelled_Q : Expired/Cancelled
    }

    state Booking {
        [*] --> Draft_B : From Quotation/Direct
        Draft_B --> Pending_B : Submitted
        Pending_B --> Approved_B : Confirmed
        Pending_B --> Rejected_B : Denied
        Approved_B --> Completed : Fulfilled (Sale/Lease)
        Approved_B --> Cancelled_B : Customer Cancelled
    }
                            

flowchart TD
    Start([Start]) --> Lead{New Enquiry}
    
    Lead -- Direct Booking --> NewBooking
    Lead -- Needs Quote --> NewQuote
    
    subgraph Quotation Process
        NewQuote[Create Sale Quotation]
        NewQuote --> CalcTax[Calculate Tax & Totals]
        CalcTax --> ApprQuote{Approval?}
        ApprQuote -- Yes --> WaitAppr[Wait for Approval]
        ApprQuote -- No --> SendQuote[Send to Customer]
        WaitAppr -- Approved --> SendQuote
        
        SendQuote --> CustAction{Customer Decision}
        CustAction -- Reject --> Lost([Lost Lead])
        CustAction -- Accept --> Convert[Convert to Booking]
    end

    subgraph Booking Process
        Convert --> NewBooking[Create Sale Booking]
        NewBooking --> CheckStock[Check Stock Availability]
        CheckStock -- Available --> Confirm[Confirm Booking]
        CheckStock -- Low Stock --> Backorder[Backorder / Wait]
        
        Confirm --> OrderType{Order Type}
        OrderType -- Cash Sale --> CashInv[Generate Cash Invoice]
        OrderType -- Lease --> LeaseProc[Start Lease Processing]
    end
    
    CashInv --> End([End])
    LeaseProc --> End