// Copyright (c) 2019 Sorgelig
//
// All rights reserved
//
// Redistribution and use in source and synthezised forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// Redistributions in synthesized form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// Neither the name of the author nor the names of other contributors may
// be used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Please report bugs to the author, but before you do so, please
// make sure that this is not a derivative work and that
// you have the latest version of this file.

module teamplayer
(
	input RESET,
	input CLK,
	input CE,

	input J3BUT,

	input P1_UP,
	input P1_DOWN,
	input P1_LEFT,
	input P1_RIGHT,
	input P1_A,
	input P1_B,
	input P1_C,
	input P1_START,
	input P1_MODE,
	input P1_X,
	input P1_Y,
	input P1_Z,

	input P2_UP,
	input P2_DOWN,
	input P2_LEFT,
	input P2_RIGHT,
	input P2_A,
	input P2_B,
	input P2_C,
	input P2_START,
	input P2_MODE,
	input P2_X,
	input P2_Y,
	input P2_Z,

	input P3_UP,
	input P3_DOWN,
	input P3_LEFT,
	input P3_RIGHT,
	input P3_A,
	input P3_B,
	input P3_C,
	input P3_START,
	input P3_MODE,
	input P3_X,
	input P3_Y,
	input P3_Z,

	input P4_UP,
	input P4_DOWN,
	input P4_LEFT,
	input P4_RIGHT,
	input P4_A,
	input P4_B,
	input P4_C,
	input P4_START,
	input P4_MODE,
	input P4_X,
	input P4_Y,
	input P4_Z,

	input P5_UP,
	input P5_DOWN,
	input P5_LEFT,
	input P5_RIGHT,
	input P5_A,
	input P5_B,
	input P5_C,
	input P5_START,
	input P5_MODE,
	input P5_X,
	input P5_Y,
	input P5_Z,

	input PAL,
	input EXPORT,

	input PORT,

	input            SEL,
	input      [4:1] A,
	input            RNW,
	input      [7:0] DI,
	output reg [7:0] DO,
	output reg       DTACK_N
);

wire [3:0] pad1qp_i[3] = '{{P1_RIGHT,P1_LEFT,P1_DOWN,P1_UP}, {P1_START,P1_A,P1_B,P1_C}, {P1_MODE,P1_X,P1_Y,P1_Z}};
wire [3:0] pad2qp_i[3] = '{{P2_RIGHT,P2_LEFT,P2_DOWN,P2_UP}, {P2_START,P2_A,P2_B,P2_C}, {P2_MODE,P2_X,P2_Y,P2_Z}};
wire [3:0] pad3qp_i[3] = '{{P3_RIGHT,P3_LEFT,P3_DOWN,P3_UP}, {P3_START,P3_A,P3_B,P3_C}, {P3_MODE,P3_X,P3_Y,P3_Z}};
wire [3:0] pad4qp_i[3] = '{{P4_RIGHT,P4_LEFT,P4_DOWN,P4_UP}, {P4_START,P4_A,P4_B,P4_C}, {P4_MODE,P4_X,P4_Y,P4_Z}};
wire [3:0] pad5qp_i[3] = '{{P5_RIGHT,P5_LEFT,P5_DOWN,P5_UP}, {P5_START,P5_A,P5_B,P5_C}, {P5_MODE,P5_X,P5_Y,P5_Z}};

wire [3:0] pad1qp[3] = PORT ? pad2qp_i : pad1qp_i;
wire [3:0] pad2qp[3] = PORT ? pad3qp_i : pad2qp_i;
wire [3:0] pad3qp[3] = PORT ? pad4qp_i : pad3qp_i;
wire [3:0] pad4qp[3] = PORT ? pad5qp_i : pad4qp_i;

wire [3:0] pad_3btn[8]  = '{pad1qp[0],pad1qp[1],pad2qp[0],pad2qp[1],pad3qp[0],pad3qp[1],pad4qp[0],pad4qp[1]};
wire [3:0] pad_6btn[12] = '{pad1qp[0],pad1qp[1],pad1qp[2],pad2qp[0],pad2qp[1],pad2qp[2],pad3qp[0],pad3qp[1],pad3qp[2],pad4qp[0],pad4qp[1],pad4qp[2]};

reg  [7:0] DAT;
reg  [7:0] CTL;
wire [1:0] new_state = DAT[6:5] | ~CTL[6:5];

wire [4:1] addr = A - PORT;

always @(posedge RESET or posedge CLK) begin

	reg [4:0] cnt;
	reg [1:0] state;
	
	if(RESET) begin
		DTACK_N <= 1;
		DO <= 8'hFF;

		DAT <= 8'h7F;
		CTL <= 8'h00;
		
		cnt  <= 0;
		state<= 3;
	end
	else begin
		if(state != new_state) begin
			if(~&cnt) cnt <= cnt + 1'd1;
			if(~state[1] & new_state[1]) cnt <= 0;
			state <= new_state;
		end
		if(CE) begin
			if(~SEL) DTACK_N <= 1;
			else if(SEL & DTACK_N) begin
				if(~RNW) begin
					// Write
					if(addr == 1) DAT <= DI;
					if(addr == 4) CTL <= DI;
				end
				else begin
					// Read
					case(cnt)
								0: DO <= {state, state[0], 4'b0011};
								1: DO <= {state, state[0], 4'b1111};
							 2,3: DO <= {state, state[0], 4'b0000};
						4,5,6,7: DO <= {state, state[0], 3'b000, ~J3BUT};
						default: DO <= {state, state[0], J3BUT ? pad_3btn[cnt[2:0]] : pad_6btn[cnt[3:0]-4'd8]};
					endcase
				end
				DTACK_N <= 0;
			end 
		end
	end
end

endmodule