from nmigen import Elaboratable, Signal, Module, Repl
from nmigen.build import Platform
from nmigen.lib.fifo import AsyncFIFOBuffered
from ..utils.ecp5pll import ECP5PLL, ECP5PLLConfig


class PllTimer(Elaboratable):
    def elaborate(self, platform: Platform):
        led1 = platform.request("led", 0)
        led4 = platform.request("led", 3)

        timer1 = Signal(25)
        fifo_buf = Signal(16)

        m = Module()

        m.submodules.pll = ECP5PLL([
            ECP5PLLConfig("sync", 25),
            ECP5PLLConfig("fast", 100, error=0),
        ])

        # Some really large depth for the FIFO
        m.submodules.fifo = fifo = AsyncFIFOBuffered(
            width=16, depth=16000, r_domain="fast", w_domain="sync")

        # Write the FIFO using the top 16 bits of the `timer1` data in the `sync` domain
        m.d.sync += timer1.eq(timer1 + 1)
        with m.If(fifo.w_rdy):
            m.d.comb += fifo.w_data.eq(timer1[9:25])
        m.d.comb += fifo.w_en.eq(1)

        # Read the FIFO in the `fast` domain, the LEDs should blink at the same time
        with m.If(fifo.r_rdy):
            m.d.fast += fifo_buf.eq(fifo.r_data)
        m.d.comb += fifo.r_en.eq(1)

        # Connect LEDs to top bits
        m.d.comb += led1.o.eq(timer1[-1])
        m.d.comb += led4.o.eq(fifo_buf[-1])

        return m