`include "util.svh"

module panel
    #(  DEBOUNCE_MAX    = 100
    )
    (   input   bit clk
    ,   input   bit reset

    ,   input   bit [8:1][12:1] led
    ,   output  bit [3:1][12:1] switch

    ,   inout   wire [10:1]  gpioa
    ,   inout   wire [28:13] gpiob
    ,   inout   wire [40:31] gpioc
    );

localparam DEBOUNCE_BITS = $clog2(DEBOUNCE_MAX+1);

enum
    {   LED_ROW1
    ,   DEAD_ROW2
    ,   LED_ROW2
    ,   DEAD_ROW3
    ,   LED_ROW3
    ,   DEAD_ROW4
    ,   LED_ROW4
    ,   DEAD_ROW5
    ,   LED_ROW5
    ,   DEAD_ROW6
    ,   LED_ROW6
    ,   DEAD_ROW7
    ,   LED_ROW7
    ,   DEAD_ROW8
    ,   LED_ROW8
    ,   DEAD_ROW9
    ,   SWITCH_PREP
    ,   SWITCH_ROW1
    ,   SWITCH_ROW2
    ,   SWITCH_ROW3
    } state;

bit [3:1][12:1] switch_raw;
bit [DEBOUNCE_BITS-1:0] switch_debounce;

`define LEDROW1 gpioc[38]
`define LEDROW2 gpioc[40]
`define LEDROW3 gpiob[15]
`define LEDROW4 gpiob[16]
`define LEDROW5 gpiob[18]
`define LEDROW6 gpiob[22]
`define LEDROW7 gpioc[37]
`define LEDROW8 gpiob[13]

`define SWROW1  gpioc[36]
`define SWROW2  gpioa[1]
`define SWROW3  gpioa[2]

`define COL1    gpioa[8]
`define COL2    gpioa[10]
`define COL3    gpioa[7]
`define COL4    gpiob[27]
`define COL5    gpioc[31]
`define COL6    gpiob[26]
`define COL7    gpiob[24]
`define COL8    gpiob[21]
`define COL9    gpiob[19]
`define COL10   gpiob[23]
`define COL11   gpioc[32]
`define COL12   gpioc[33]

`define DO_LEDS
`define DO_SWITCHES

always_ff @(posedge clk) begin
    // LED rows (active high)
    `LEDROW1    = 1'b0;
    `LEDROW2    = 1'b0;
    `LEDROW3    = 1'b0;
    `LEDROW4    = 1'b0;
    `LEDROW5    = 1'b0;
    `LEDROW6    = 1'b0;
    `LEDROW7    = 1'b0;
    `LEDROW8    = 1'b0;

    // Switch rows (active low)
    `SWROW1     = 1'b1;
    `SWROW2     = 1'b1;
    `SWROW3     = 1'b1;

    if (reset) begin
        switch = 0;
        switch_raw = 0;
        switch_debounce = 0;
        state = state.first;
    end else begin
        automatic bit [3:1][12:1] new_switch = switch_raw;

        case (state)
`ifdef DO_LEDS
`define LED_ROW(n) \
            LED_ROW``n: begin \
                `LEDROW``n  = 1'b1; \
                `COL1       = ~led[n][1]; \
                `COL2       = ~led[n][2]; \
                `COL3       = ~led[n][3]; \
                `COL4       = ~led[n][4]; \
                `COL5       = ~led[n][5]; \
                `COL6       = ~led[n][6]; \
                `COL7       = ~led[n][7]; \
                `COL8       = ~led[n][8]; \
                `COL9       = ~led[n][9]; \
                `COL10      = ~led[n][10]; \
                `COL11      = ~led[n][11]; \
                `COL12      = ~led[n][12]; \
            end

            `LED_ROW(1)
            `LED_ROW(2)
            `LED_ROW(3)
            `LED_ROW(4)
            `LED_ROW(5)
            `LED_ROW(6)
            `LED_ROW(7)
            `LED_ROW(8)
`endif

`ifdef DO_SWITCHES
            SWITCH_PREP: begin
                `SWROW1 = 1'b0;

                `COL1   = 1'bZ;
                `COL2   = 1'bZ;
                `COL3   = 1'bZ;
                `COL4   = 1'bZ;
                `COL5   = 1'bZ;
                `COL6   = 1'bZ;
                `COL7   = 1'bZ;
                `COL8   = 1'bZ;
                `COL9   = 1'bZ;
                `COL10  = 1'bZ;
                `COL11  = 1'bZ;
                `COL12  = 1'bZ;
            end

            SWITCH_ROW1: begin
                `SWROW2 = 1'b0;

                new_switch[1][1]    = ~`COL1;
                new_switch[1][2]    = ~`COL2;
                new_switch[1][3]    = ~`COL3;
                new_switch[1][4]    = ~`COL4;
                new_switch[1][5]    = ~`COL5;
                new_switch[1][6]    = ~`COL6;
                new_switch[1][7]    = ~`COL7;
                new_switch[1][8]    = ~`COL8;
                new_switch[1][9]    = ~`COL9;
                new_switch[1][10]   = ~`COL10;
                new_switch[1][11]   = ~`COL11;
                new_switch[1][12]   = ~`COL12;
            end

            SWITCH_ROW2: begin
                `SWROW3 = 1'b0;

                new_switch[2][1]    = ~`COL1;
                new_switch[2][2]    = ~`COL2;
                new_switch[2][3]    = ~`COL3;
                new_switch[2][4]    = ~`COL4;
                new_switch[2][5]    = ~`COL5;
                new_switch[2][6]    = ~`COL6;
                new_switch[2][7]    = ~`COL7;
                new_switch[2][8]    = ~`COL8;
                new_switch[2][9]    = ~`COL9;
                new_switch[2][10]   = ~`COL10;
                new_switch[2][11]   = ~`COL11;
                new_switch[2][12]   = ~`COL12;
            end

            SWITCH_ROW3: begin
                new_switch[3][1]    = ~`COL1;
                new_switch[3][2]    = ~`COL2;
                new_switch[3][3]    = ~`COL3;
                new_switch[3][4]    = ~`COL4;
                new_switch[3][5]    = ~`COL5;
                new_switch[3][6]    = ~`COL6;
                new_switch[3][7]    = ~`COL7;
                new_switch[3][8]    = ~`COL8;
                new_switch[3][9]    = ~`COL9;
                new_switch[3][10]   = ~`COL10;
                new_switch[3][11]   = ~`COL11;
                new_switch[3][12]   = ~`COL12;
            end
`endif
        endcase

        if (state == state.last)
            state = state.first;
        else
            state = state.next;

        if (new_switch == switch_raw) begin
            if (switch_debounce == 0)
                switch = switch_raw;
            else
                --switch_debounce;
        end else begin
            switch_raw = new_switch;
            switch_debounce = DEBOUNCE_MAX;
        end
    end
end

endmodule