// retroDE_ps2 — tb_top_psmct32_feeder_accum_demo (Ch336)
//
// >FIFO_DEPTH FRAMEBUFFER ACCUMULATION. A 14-primitive scene (FIFO depth 8) renders in TWO batches
// that COMPOSE into one framebuffer instead of wiping each other:
//   batch 0 (prims 0-7,  tiles 0-7)  = RED   — clears + full-flushes
//   batch 1 (prims 8-13, tiles 8-13) = BLUE  — sparse-flushes onto the accumulated FB
// PROOF: at the end, the RED batch-0 tiles AND the BLUE batch-1 tiles are SIMULTANEOUSLY visible.
// If batches wiped each other (the pre-Ch336 behavior), tiles 0-7 would be green. v1 = color
// accumulation + per-batch Z (non-overlapping/tile-separated, so the per-batch-Z limit is honest).

`timescale 1ns/1ps

module tb_top_psmct32_feeder_accum_demo;

    localparam int H_ACTIVE = 64, V_ACTIVE = 64;
    localparam real MARG = 0.12;

    logic clk, rst_n;
    initial clk = 1'b0;
    always #5 clk = ~clk;

    logic        core_go;
    logic [7:0]  r, g, b;
    logic        hsync, vsync, de;
    logic        core_halt, dma_done_seen, frame_seen, raster_overflow;
    logic        frame_toggle, dma_done_toggle;

    top_psmct32_raster_demo_bram #(
        .H_ACTIVE(H_ACTIVE), .V_ACTIVE(V_ACTIVE),
        .VRAM_BYTES(32*1024), .PSMCT32_SWIZZLE(1'b0),
        .COMBINED_TAZ(1'b1), .TILE_LOCAL(1'b1), .TILE_COLS(4), .TILE_ROWS(4),
        .TILE_MULTIPRIM(1'b1), .TILE_PRIM_COUNT(4), .TILE_FIFO_DEPTH(8),
        .BIN_BUFFER_ENABLE(1'b1), .HEARTBEAT_SPLICE_ENABLE(1'b0),
        .FEEDER_ENABLE(1'b1), .FEEDER_STG_WORDS(256)
    ) dut (
        .clk(clk), .rst_n(rst_n), .core_go(core_go),
        .r(r), .g(g), .b(b), .hsync(hsync), .vsync(vsync), .de(de),
        .core_halt(core_halt), .dma_done_seen(dma_done_seen),
        .frame_seen(frame_seen), .raster_overflow(raster_overflow),
        .frame_toggle(frame_toggle), .dma_done_toggle(dma_done_toggle),
        .joy_a_pressed_i(1'b0), .joy_b_pressed_i(1'b0),
        .feeder_stg_we_i(1'b0), .feeder_stg_waddr_i(12'd0), .feeder_stg_wdata_i(64'd0),
        .feeder_go_i(feeder_go_tb),
        .feeder_ready_o(feeder_ready_tb), .feeder_records_o(), .feeder_waits_o()
    );
    logic feeder_go_tb;
    logic feeder_ready_tb;

    logic [7:0] cap_r[0:V_ACTIVE-1][0:H_ACTIVE-1], cap_g[0:V_ACTIVE-1][0:H_ACTIVE-1], cap_b[0:V_ACTIVE-1][0:H_ACTIVE-1];
    logic       cap_de[0:V_ACTIVE-1][0:H_ACTIVE-1];
    bit capture_armed;
    task automatic clear_cap;
        for (int y=0;y<V_ACTIVE;y++) for (int x=0;x<H_ACTIVE;x++) begin
            cap_r[y][x]=0; cap_g[y][x]=0; cap_b[y][x]=0; cap_de[y][x]=0; end
    endtask
    initial begin clear_cap(); capture_armed=1'b0; end
    logic [31:0] hcnt_d, vcnt_d;
    always_ff @(posedge clk) begin
        if (!rst_n) begin hcnt_d<=0; vcnt_d<=0; end
        else begin hcnt_d<=32'(dut.u_pcrtc.hcnt); vcnt_d<=32'(dut.u_pcrtc.vcnt); end
    end
    always_ff @(posedge clk)
        if (rst_n && capture_armed && de && (vcnt_d<V_ACTIVE) && (hcnt_d<H_ACTIVE)) begin
            cap_r[vcnt_d][hcnt_d]<=r; cap_g[vcnt_d][hcnt_d]<=g; cap_b[vcnt_d][hcnt_d]<=b; cap_de[vcnt_d][hcnt_d]<=1'b1; end

    function automatic int color_in_box(input int bx0, input int by0, input logic [7:0] er, eg, eb);
        int n; begin n=0;
            for (int y=by0;y<by0+16;y++) for (int x=bx0;x<bx0+16;x++)
                if (cap_de[y][x] && cap_r[y][x]===er && cap_g[y][x]===eg && cap_b[y][x]===eb) n++;
            color_in_box = n;
        end
    endfunction

    int errors;
    localparam logic [7:0] FF=8'hFF, ZZ=8'h00;

    // Re-arm the frame capture and sample two whole frames into cap_*.
    task automatic recapture;
        repeat(200000) @(posedge clk);
        @(posedge dut.u_pcrtc.end_of_frame); @(posedge clk); clear_cap(); capture_armed=1'b1;
        @(posedge dut.u_pcrtc.end_of_frame); @(posedge clk); capture_armed=1'b0;
    endtask

    initial begin
        errors=0; feeder_go_tb=1'b0;
        // BOARD-FAITHFUL boot: the bitstream-inits feeder_stg to LIST-A (cap4, all-textured boot
        // splash) and renders it ONCE at boot, leaving its render state behind. The board then GOes
        // the accum scene as the FIRST retrigger. The old auto-run loaded accum at boot (clean state)
        // and so never reproduced the first-GO-after-boot color poisoning.
        $readmemh(`FEEDER_LISTA_FILE, dut.g_feeder.feeder_stg);

        rst_n=1'b0; core_go=1'b0;
        repeat(4) @(posedge clk); rst_n=1'b1; repeat(8) @(posedge clk);
        @(negedge clk); core_go=1'b1; @(negedge clk); core_go=1'b0;
        wait (core_halt==1'b1); repeat(4) @(posedge clk);
        wait (dma_done_seen==1'b1); repeat(10) @(posedge clk);
        if (dut.xfer_busy==1'b1) wait (dut.xfer_busy==1'b0);
        wait (feeder_ready_tb==1'b1);   // list-A rendered, control FSM back in C_READY

        // ---- GO 1 : FIRST accum GO after boot (the board's failing path) ----
        $readmemh(`FEEDER_ACCUM_FILE, dut.g_feeder.feeder_stg);
        @(negedge clk); feeder_go_tb=1'b1; @(negedge clk); feeder_go_tb=1'b0;
        recapture();
        // batch 0 (tiles 0-7) RED must SURVIVE batch 1 — accumulation proof.
        for (int t=0;t<8;t++)
            if (color_in_box((t%4)*16,(t/4)*16, FF,ZZ,ZZ) < 15) begin
                $error("[accum GO1] batch-0 tile %0d not RED (%0d px)", t, color_in_box((t%4)*16,(t/4)*16,FF,ZZ,ZZ)); errors++; end
        // batch 1 (tiles 8-13) BLUE — the bit the board renders RED on the first GO.
        for (int t=8;t<14;t++)
            if (color_in_box((t%4)*16,(t/4)*16, ZZ,ZZ,FF) < 15) begin
                $error("[accum GO1] batch-1 tile %0d not BLUE (%0d px) <-- board shows RED on first GO", t, color_in_box((t%4)*16,(t/4)*16,ZZ,ZZ,FF)); errors++; end
        if (int'(dut.feeder_records) != 14) begin $error("[accum GO1] records=%0d (want 14)", int'(dut.feeder_records)); errors++; end
        if (raster_overflow) begin $error("[accum GO1] raster_overflow set"); errors++; end
        $display("[accum GO1] batch0 RED: t0=%0d t7=%0d | batch1 BLUE: t8=%0d t13=%0d | t8 as RED=%0d | records=%0d",
                 color_in_box(0,0,FF,ZZ,ZZ), color_in_box(48,16,FF,ZZ,ZZ),
                 color_in_box(0,32,ZZ,ZZ,FF), color_in_box(16,48,ZZ,ZZ,FF), color_in_box(0,32,FF,ZZ,ZZ), int'(dut.feeder_records));

        // ---- GO 2 : second accum GO (board renders this correctly) ----
        wait (feeder_ready_tb==1'b1);
        @(negedge clk); feeder_go_tb=1'b1; @(negedge clk); feeder_go_tb=1'b0;
        recapture();
        for (int t=8;t<14;t++)
            if (color_in_box((t%4)*16,(t/4)*16, ZZ,ZZ,FF) < 15) begin
                $error("[accum GO2] batch-1 tile %0d not BLUE (%0d px)", t, color_in_box((t%4)*16,(t/4)*16,ZZ,ZZ,FF)); errors++; end
        $display("[accum GO2] batch0 RED: t0=%0d t7=%0d | batch1 BLUE: t8=%0d t13=%0d | records=%0d",
                 color_in_box(0,0,FF,ZZ,ZZ), color_in_box(48,16,FF,ZZ,ZZ),
                 color_in_box(0,32,ZZ,ZZ,FF), color_in_box(16,48,ZZ,ZZ,FF), int'(dut.feeder_records));

        $display("[tb_top_psmct32_feeder_accum_demo] errors=%0d", errors);
        if (errors==0) $display("[tb_top_psmct32_feeder_accum_demo] PASS");
        else           $display("[tb_top_psmct32_feeder_accum_demo] FAIL");
        $finish;
    end
    initial begin #1500000000; $error("[tb_top_psmct32_feeder_accum_demo] TIMEOUT"); $finish; end
endmodule : tb_top_psmct32_feeder_accum_demo
