entity Second(in clk: bit, out ready: bit) {
  let index: uint{..1200000} = 0;

  on clk.posedge {
      if index == 12000000 - 1 {
          ready <= 1;
      } else {
          index <= index + 1;
          ready <= 0;
      }
  }
}

entity Half(in clk: bit, out ready: bit) {
  let index: uint{..1200000} = 0;

  on clk.posedge {
      if index == 10000000 - 1 {
          ready <= 1;
      } else {
          index <= index + 1;
          ready <= 0;
      }
  }
}

entity Other(
    in rst: bit,
    in clk: bit,
    in trigger: bit,
    out ready: bit,
    in LED: bit,
) {
    let _FSM: bit[9] = 0;
    on clk.negedge {
        if !rst {
            ready <= 0;
        } else {
            fsm {
                yield;
                yield;
                yield;
                yield;
                yield;
                ready <= 1;
                yield;

                // Wait for trigger.
                while !trigger {
                    yield;
                }
                LED <= 1;
            }
        }
    }
}

entity Ethernet(
    in rst: bit,
    in tx_clk: bit,
    out LED1: bit,
    out LED2: bit,
    out LED3: bit,
    out LED4: bit,
    out CS: bit,
    out spi_bit: bit, // MOSI
    in spi_rx: bit, // MISO
    out spi_clk: bit,
) {
    // Internal values.
    let other_trigger;
    let other_ready;
    let spi = Other {
        rst: rst,
        clk: tx_clk,
        trigger: other_trigger,
        ready: other_ready,
        LED: LED1,
    };

    let _FSM: bit[9] = 0;
    let dummy: bit[2];
    on tx_clk.negedge {
        if !rst {
            _FSM <= 0;
            other_trigger <= 1;
            dummy <= 0;
        } else {
            match dummy {
                0 => {
                    other_trigger <= 1;
                    dummy <= 1;
                }
                1 => {
                    if other_ready {
                        other_trigger := 0;
                        LED2 <= 1;
                        dummy <= 2;
                    } else {
                        other_trigger := 1;
                    }
                },
                2 => {
                },
            }
            // fsm {
            //     await other_ready;
            //     other_trigger := 0;
            //     LED2 <= 1;
            //
            //     loop { yield; }
            // }
        }
    }
}

entity Main(
    in clk: bit,
    out LED1: bit,
    out LED2: bit,
    out LED3: bit,
    out LED4: bit,
    out LED5: bit,
    out PMOD1: bit,
    out PMOD2: bit,
    in PMOD3: bit,
    out PMOD4: bit,
    out PMOD7: bit,
    //PMOD8: out,
    //PMOD9: out,
    //PMOD10: out,
) {
    // PMOD1 = CS
    // PMOD2 = MOSI
    // PMOD3 = MISO
    // PMOD4 = SCLK
    let ready;
    let sec = Second { clk: clk, ready: ready };
    let ether = Ethernet {
        rst: ready,
        tx_clk: clk,
        LED1: LED1,
        LED2: LED2,
        LED3: LED3,
        LED4: LED4,
        CS: PMOD1,
        spi_bit: PMOD2,
        spi_rx: PMOD3,
        spi_clk: PMOD4,
    };

    always {
        LED5 = !ready;
    }
}