#!/usr/bin/env python3

from tinygrad.tensor import Tensor
from tinygrad.helpers import dtypes
from tinygrad.nn import Linear, Embedding
from tinygrad.nn.optim import SGD
from tinygrad.jit import TinyJit
from extra.training import sparse_categorical_crossentropy
import random
import numpy as np
import numpy.random as npr

words = ['lorem', 'ipsum', 'dolor', 'sit', 'amet', 'consectetur', 'adipiscing',
         'elit', 'sed', 'do', 'eiusmod', 'tempor', 'incididunt', 'ut', 'labore', 'et',
         'dolore', 'magna', 'aliqua', 'ut', 'enim', 'ad', 'minim', 'veniam', 'quis',
         'nostrud', 'exercitation', 'ullamco', 'laboris', 'nisi', 'ut', 'aliquip', 'ex',
         'ea', 'commodo', 'consequat', 'duis', 'aute', 'irure', 'dolor', 'in',
         'reprehenderit', 'in', 'voluptate', 'velit', 'esse', 'cillum', 'dolore', 'eu',
         'fugiat', 'nulla', 'pariatur', 'excepteur', 'sint', 'occaecat', 'cupidatat',
         'non', 'proident', 'sunt', 'in', 'culpa', 'qui', 'officia', 'deserunt',
         'mollit', 'anim', 'id', 'est', 'laborum']

def atoi(char):
    if char == '.':
        return 0
    assert char >= "a" and char <= "z"
    return ord(char) - ord("a") + 1

def itoa(char):
    charint = int(char)
    if charint == 0:
        return "."
    assert char >= 1 and char <= 26
    return chr(charint -1 + ord('a'))

def dataset(words, block_size=3):
    X, Y = [], []
    for word in words:
        window = [0] * block_size  # sliding window context
        for ch in word + ".":
            ix = atoi(ch)
            X.append(window)
            Y.append(ix)
            window = window[1:] + [ix]
    return np.array(X, dtype=np.float32), np.array(Y, dtype=np.float32)

class Model:
    def __init__(self, emb_size=10, hidden_n=100, vocab_size=27):
        self.emb = Embedding(vocab_size, emb_size)
        self.l1 = Linear(emb_size * block_size, hidden_n)
        self.l2 = Linear(hidden_n, vocab_size)

    def __call__(self, x, training=True):
        if training:
            for p in self.parameters():
                p.requires_grad = True
        emb = self.emb(x)
        h = self.l1(emb.reshape(emb.shape[0], -1)).tanh()
        logits = self.l2(h)
        return logits

    def parameters(self):
        return [self.l1.weight, self.l1.bias, self.l2.weight, self.l2.bias, self.emb.weight]

@TinyJit
def jitloss(x,y):
  return sparse_categorical_crossentropy(x, y).realize()

block_size=3
random.shuffle(words)
X,Y = dataset(words, block_size)
m = Model()
opt = SGD(m.parameters(), lr=0.1)

for step in range(1000):
    batch_ix = npr.randint(0, X.shape[0], (32,))
    x_batch, y_batch = Tensor(X[batch_ix], requires_grad=False), Y[batch_ix]

    logits = m(x_batch)
    loss = jitloss(logits, y_batch)

    opt.zero_grad()

    loss.backward()
    if m.parameters()[0].grad is None:
        break

    opt.step()

    if step % 100 == 0:
        print(f"Step {step+1} | Loss: {loss.numpy()}")