output_logic.v

module output_logic #(
    parameter CURRENCY_WIDTH = 7,
    parameter ITEM_ADDR_WIDTH = 10
)(
    input  wire clk,
    input  wire rstn,
    input  wire selection_ready,
    input  wire currency_ready,
    input  wire [CURRENCY_WIDTH-1:0] total_currency,
    input  wire [15:0] item_price,
    input  wire [7:0] avail_count,
    input  wire [ITEM_ADDR_WIDTH-1:0] selected_item,
    output reg  dispense_valid,
    output reg  [ITEM_ADDR_WIDTH-1:0] item_dispensed,
    output reg  [CURRENCY_WIDTH-1:0] currency_change,
    output reg  trigger_dispense
);

    // Internal latching flags
    reg item_ready_flag;
    reg money_ready_flag;
    reg [CURRENCY_WIDTH-1:0] latched_currency;
    reg [ITEM_ADDR_WIDTH-1:0] latched_item;

    always @(posedge clk or negedge rstn) begin
        if (!rstn) begin
            item_ready_flag <= 0;
            money_ready_flag <= 0;
            latched_currency <= 0;
            latched_item <= 0;
            dispense_valid <= 0;
            item_dispensed <= 0;
            currency_change <= 0;
            trigger_dispense <= 0;
        end else begin
            dispense_valid <= 0;
            trigger_dispense <= 0;

            // Latch item selection
            if (selection_ready) begin
                item_ready_flag <= 1;
                latched_item <= selected_item;
            end

            // Latch currency
            if (currency_ready) begin
                money_ready_flag <= 1;
                latched_currency <= total_currency;
            end

            // Only proceed when both are latched
            if (item_ready_flag && money_ready_flag) begin
                if (avail_count > 0 && latched_currency >= item_price) begin
                    dispense_valid <= 1;
                    item_dispensed <= latched_item;
                    currency_change <= latched_currency - item_price;
                    trigger_dispense <= 1;
                end else begin
                    dispense_valid <= 0;
                    item_dispensed <= latched_item;
                    currency_change <= latched_currency;
                    trigger_dispense <= 0;
                end

                // Clear flags after processing
                item_ready_flag <= 0;
                money_ready_flag <= 0;
            end
        end
    end
endmodule