# model based off https://medium.com/data-science/going-beyond-99-mnist-handwritten-digits-recognition-cfff96337392
from typing import Callable
from tinygrad import Tensor, TinyJit, nn, GlobalCounters, function, Context
from tinygrad.helpers import getenv, colored, trange
from tinygrad.nn.datasets import mnist

class Model:
  def __init__(self):
    self.layers: list[Callable[[Tensor], Tensor]] = [
      nn.Conv2d(1, 32, 5), Tensor.relu,
      nn.Conv2d(32, 32, 5), Tensor.relu,
      nn.BatchNorm(32), Tensor.max_pool2d,
      nn.Conv2d(32, 64, 3), Tensor.relu,
      nn.Conv2d(64, 64, 3), Tensor.relu,
      nn.BatchNorm(64), Tensor.max_pool2d,
      lambda x: x.flatten(1), nn.Linear(576, 10)]

  @function
  def __call__(self, x:Tensor) -> Tensor: return x.sequential(self.layers)

  @TinyJit
  @Context(TRAINING=1)
  def train_step(self, X_train:Tensor, Y_train:Tensor) -> Tensor:
    opt.zero_grad()
    samples = Tensor.randint(getenv("BS", 512), high=X_train.shape[0])
    loss = self(X_train[samples]).sparse_categorical_crossentropy(Y_train[samples]).backward()
    return loss.realize(*opt.schedule_step())

  @TinyJit
  def get_test_acc(self, X_test:Tensor, Y_test:Tensor) -> Tensor: return (self(X_test).argmax(axis=1) == Y_test).mean()*100

if __name__ == "__main__":
  X_train, Y_train, X_test, Y_test = mnist(fashion=getenv("FASHION"))

  model = Model()
  opt = (nn.optim.Muon if getenv("MUON") else nn.optim.SGD if getenv("SGD") else nn.optim.Adam)(nn.state.get_parameters(model))

  test_acc = float('nan')
  for i in (t:=trange(getenv("STEPS", 70))):
    GlobalCounters.reset()   # NOTE: this makes it nice for DEBUG=2 timing
    loss = model.train_step(X_train, Y_train)
    if i%10 == 9: test_acc = model.get_test_acc(X_test, Y_test).item()
    t.set_description(f"loss: {loss.item():6.2f} test_accuracy: {test_acc:5.2f}%")

  # verify eval acc
  if target := getenv("TARGET_EVAL_ACC_PCT", 0.0):
    if test_acc >= target and test_acc != 100.0: print(colored(f"{test_acc=} >= {target}", "green"))
    else: raise ValueError(colored(f"{test_acc=} < {target}", "red"))