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"""Medium-length EQL experiment (10+10 epochs) to verify full pipeline."""
import os, sys, time
import numpy as np
from tqdm import tqdm
from scipy.io import loadmat
import tensorflow as tf
import matplotlib
matplotlib.use('Agg')
from matplotlib import pyplot as plt

from reproduce_eql import (
    SymbolicNet, Constant, Identity, Square, Sin, Sigmoid, Product,
    count_double, l12_smooth, get_folders_started, record_base_info,
    append_text_to_summary, plot_train_vs_validation, plot_histogram,
    plot_descaled_real_vs_prediction, generate_all_data, generate_variable_list,
    save_weights, network
)

if __name__ == "__main__":
    target_city = "Roskilde"
    steps_ahead = 6
    feature = "wind_speed"
    target_cities = ["Esbjerg", "Odense", "Roskilde"]
    city_index = target_cities.index(target_city)

    data = loadmat('Denmark_data/wind_speed/step1.mat')
    y_min = data["y_min_tr"][0][city_index]
    y_max = data["y_max_tr"][0][city_index]

    config = {
        "use_rescaled_MSE": True,
        "a_L_0.5": 5e-3,
        "threshold_value": 7.5e-3,
        "lambda_reg": 3.0,
        "steps_ahead": 6,
        "feature": feature,
        "target_city": target_city,
        "epochs1": 10,
        "epochs2": 10,
        "use_phase2": True,
        "batch_size": 200,
        "phase1_lr": 1e-4,
        "phase2_lr": 1e-5,
        "eql_number_layers": 2,
        "optimizer": "rmsprop",
    }

    x_dim = 80
    activation_funcs = [
        *[Constant()] * 2, *[Identity()] * 4, *[Square()] * 4,
        *[Sin()] * 2, *[Sigmoid()] * 2, *[Product()] * 2
    ]
    n_layers = 2
    n_double = count_double(activation_funcs)
    width = len(activation_funcs)

    init_weights = [
        tf.random.truncated_normal([x_dim, width + n_double], stddev=0.1),
        tf.random.truncated_normal([width, width + n_double], stddev=0.5),
        tf.random.truncated_normal([width, 1], stddev=1.0)
    ]
    model = SymbolicNet(n_layers, funcs=activation_funcs, initial_weights=init_weights)
    phase1_optimizer = tf.keras.optimizers.RMSprop(learning_rate=1e-4)

    experiment_number = get_folders_started()
    print("\n" + "*" * 10 + " Experiment {} ".format(experiment_number) + "*" * 10 + "\n")
    record_base_info(experiment_number, **config)

    x_train, y_train = generate_all_data("train", steps_ahead, feature, city_index)
    x_test, y_test = generate_all_data("test", steps_ahead, feature, city_index)
    train_dataset = tf.data.Dataset.from_tensor_slices((x_train, y_train)).batch(200)
    val_dataset = tf.data.Dataset.from_tensor_slices((x_test, y_test)).batch(200)

    # Phase 1
    best_val_loss = float('inf')
    best_val_weights = None
    train_loss_results = []
    valid_loss_results = []

    for epoch in range(config["epochs1"]):
        epoch_loss_avg = tf.keras.metrics.MeanSquaredError()
        for xb, yb in tqdm(train_dataset, desc=f"P1 Epoch {epoch+1}", leave=False):
            with tf.GradientTape() as tape:
                yp = model(xb)
                err = tf.keras.losses.MeanSquaredError()(yb * (y_max - y_min) + y_min, yp * (y_max - y_min) + y_min)
                reg = l12_smooth(model.get_weights(), 5e-3)
                loss = err + 3.0 * reg
            grads = tape.gradient(loss, model.get_weights())
            phase1_optimizer.apply_gradients(zip(grads, model.get_weights()))
            epoch_loss_avg.update_state(yb, yp)

        train_mse = epoch_loss_avg.result().numpy()
        val_mse = tf.keras.metrics.MeanSquaredError()
        for xv, yv in val_dataset:
            val_mse.update_state(yv, model(xv))
        val_mse = val_mse.result().numpy()

        train_loss_results.append(train_mse)
        valid_loss_results.append(val_mse)
        if val_mse < best_val_loss:
            best_val_loss = val_mse
            best_val_weights = [w.numpy() for w in model.get_weights()]
            print(f"P1 Epoch {epoch+1}: val MSE improved to {val_mse:.4e} (train {train_mse:.4e})")
        else:
            print(f"P1 Epoch {epoch+1}: val MSE {val_mse:.4e} (train {train_mse:.4e})")

    save_weights(best_val_weights, experiment_number, "phase1", best_val_loss)
    append_text_to_summary(experiment_number, f"phase 1 best MSE validation: {best_val_loss}\n")
    plot_train_vs_validation(experiment_number, config["epochs1"], train_loss_results, valid_loss_results, "phase1")
    plot_histogram(experiment_number, best_val_weights[0], "phase1", "weights1", 5e-3)
    plot_histogram(experiment_number, best_val_weights[1], "phase1", "weights2", 5e-3)
    plot_histogram(experiment_number, best_val_weights[2], "phase1", "weights3", 5e-3)

    # Phase 2
    masked_weights = []
    for w_i in best_val_weights:
        mask = tf.cast(tf.constant(tf.abs(w_i) > 7.5e-3), tf.float32)
        masked_weights.append(tf.multiply(w_i, mask))

    model2 = SymbolicNet(n_layers, funcs=activation_funcs, initial_weights=masked_weights)
    opt2 = tf.keras.optimizers.RMSprop(learning_rate=1e-5)

    train_loss_results2 = []
    valid_loss_results2 = []
    best_val_loss2 = float('inf')
    best_val_weights2 = None

    for epoch in range(config["epochs2"]):
        epoch_loss_avg = tf.keras.metrics.MeanSquaredError()
        for xb, yb in tqdm(train_dataset, desc=f"P2 Epoch {epoch+1}", leave=False):
            with tf.GradientTape() as tape:
                yp = model2(xb)
                err = tf.keras.losses.MeanSquaredError()(yb * (y_max - y_min) + y_min, yp * (y_max - y_min) + y_min)
            grads = tape.gradient(err, model2.get_weights())
            opt2.apply_gradients(zip(grads, model2.get_weights()))
            epoch_loss_avg.update_state(yb, yp)

        train_mse = epoch_loss_avg.result().numpy()
        val_mse = tf.keras.metrics.MeanSquaredError()
        for xv, yv in val_dataset:
            val_mse.update_state(yv, model2(xv))
        val_mse = val_mse.result().numpy()

        train_loss_results2.append(train_mse)
        valid_loss_results2.append(val_mse)
        if val_mse < best_val_loss2:
            best_val_loss2 = val_mse
            best_val_weights2 = [w.numpy() for w in model2.get_weights()]
            print(f"P2 Epoch {epoch+1}: val MSE improved to {val_mse:.4e} (train {train_mse:.4e})")
        else:
            print(f"P2 Epoch {epoch+1}: val MSE {val_mse:.4e} (train {train_mse:.4e})")

    save_weights(best_val_weights2, experiment_number, "phase2", best_val_loss2)
    plot_train_vs_validation(experiment_number, config["epochs2"], train_loss_results2, valid_loss_results2, "phase2")

    expr = network(best_val_weights2, activation_funcs, generate_variable_list(26, 80)[:80], threshold=0)
    append_text_to_summary(experiment_number, f"Formula after phase2: {expr}\n")
    print(f"\nExtracted formula: {expr}")

    best_model = SymbolicNet(n_layers, funcs=activation_funcs,
                             initial_weights=[tf.constant(w) for w in best_val_weights2])
    yp = best_model(x_test)
    mae = plot_descaled_real_vs_prediction(experiment_number, y_test, yp, y_min, y_max)
    append_text_to_summary(experiment_number, f"MAE: {mae}\n")
    print(f"\nMAE: {mae}")
    print("\nMedium experiment complete!")