import numpy as np
from collections.abc import Callable
from params import RbmParams
from state import RbmState
from matrix import sample, prob, rms_error_accu
from status import Status
from cd_train import cd_jens

class Layer:
	def __init__(self, name: str, shape: tuple[int, int, int, int], params: RbmParams):
		self.name = name
		self.shape = shape
		self.state = RbmState.from_layer_params((shape[0]*shape[1]+shape[2], shape[3]))
		self.params = params
		self.state_filename = f"{self.name}_state.npz"

	def init(self, std: float):
		self.state.init(mu=0, std=std)

	def save(self, filename: str = None):
		if filename is None:
			filename = self.state_filename
		self.state.to_file(filename)

	def load(self, filename: str = None):
		if filename is None:
			filename = self.state_filename
		state = RbmState.from_file(filename)
		if state is not None:
			self.state = state

	def train(self, batch: np.ndarray, cd_func: Callable, status: Status):
		training_remain = batch.shape[0]
		batch_size = min(self.params.mini_batch_size, training_remain)
		if batch_size == 0:
			batch_size = training_remain

		status.on_change({})
		d_progress = 100.0 / (training_remain/batch_size * self.params.num_epochs)
		batch_row_index = 0
		training_seen = 0
		keep_running = True
		while training_remain > 0 and keep_running:
			batch_size_remain = min(batch_size, training_remain)
			mini_batch = batch[batch_row_index:batch_row_index + batch_size_remain]
			training_remain -= batch_size_remain
			batch_row_index += batch_size_remain

			inc_bv = np.zeros(self.state.b_v.shape)
			inc_bh = np.zeros(self.state.b_h.shape)
			inc_whv = np.zeros(self.state.w_hv.shape)

			v_states = mini_batch
			if self.params.do_batch_sample:
				v_states = sample(mini_batch)

			for epochs in range(self.params.num_epochs):
				# Contrastive divergence learning: calculate gradients
				dwhv, dbv, dbh = cd_func(v_states, self.params, self.v_to_ph, self.h_to_pv)

				# Adjust weight and biases
				kl = self.params.learning_rate/batch_size
				inc_bv = self.params.momentum*inc_bv + kl*dbv
				inc_bh = self.params.momentum*inc_bh + kl*dbh
				inc_whv = self.params.momentum*inc_whv + kl*dwhv - self.params.weight_decay*self.state.w_hv

				self.state.b_v += inc_bv
				self.state.b_h += inc_bh
				self.state.w_hv += inc_whv

				# Calculate	error
				err_rms = rms_error_accu(mini_batch - self.h_to_pv(self.v_to_ph(v_states)))
				if not status.on_change({"progress": {"value": round(training_seen*d_progress), "unit": "%"}, "err_rms": {"value": err_rms, "unit": ""}}):
					keep_running = False
					break

				training_seen += 1

	def v_to_ph(self, v: np.ndarray) -> np.ndarray:
		state = self.state.v_to_h(v)
		if self.params.do_gaussian_visible:
			return state

		return prob(state)

	def h_to_pv(self, h: np.ndarray) -> np.ndarray:
		state = self.state.h_to_v(h)
		if self.params.do_gaussian_visible:
			return state

		return prob(state)


	def gibbs_v_to_h(self, v: np.ndarray) -> np.ndarray:
		h = None
		for i in range(self.params.num_gibbs_samples):
			h = self.v_to_ph(v)
			v = self.h_to_pv(h)

		return h

	def gibbs_h_to_v(self, h: np.ndarray) -> np.ndarray:
		v = None
		for i in range(self.params.num_gibbs_samples):
			v = self.h_to_pv(h)
			h = self.v_to_ph(v)

		return v

def xor():
	# Create params
	params = RbmParams()
	params.do_rao_blackwell = True
	params.num_gibbs_samples = 3

	# Create layer
	layer = Layer("Layer_0", (3, 1, 0, 16), params)

	# Init weights
	layer.init(0.01)

	# Load weights (if exists)
	layer.load()

	# Prepare training data
	training_batch = np.array([[0,1,1], [0,0,0], [1,1,0], [1,0,1]], dtype=np.float64)

	# Train layer
	layer.train(training_batch, cd_jens, Status())

	# Save weights
	layer.save()

	# Test with test data
	test_batch = np.array([[0,0,0], [0,1,0], [1,0,0], [1,1,0]], dtype=np.float64)
	for pattern in test_batch:
		h = layer.gibbs_v_to_h(pattern)
		v = layer.gibbs_h_to_v(h)
		print(f"P{pattern} : {v}")


if __name__ == "__main__":
	xor()
	print("Test: [passed]")