/// Integration test for QuantizedTFT forward() implementation
///
/// Validates end-to-end forward pass with all 6 sub-methods integrated
use candle_core::{DType, Device, Tensor};
use ml::memory_optimization::quantization::{QuantizationConfig, QuantizationType, Quantizer};
use ml::tft::{QuantizedTemporalFusionTransformer, TFTConfig};
use ml::MLError;
use std::collections::HashMap;

#[test]
fn test_forward_pass_basic() -> Result<(), MLError> {
    // Test configuration
    let config = TFTConfig {
        input_dim: 54,
        hidden_dim: 256,
        num_heads: 8,
        num_layers: 4,
        prediction_horizon: 10,
        sequence_length: 60,
        num_quantiles: 3,
        num_static_features: 20,
        num_known_features: 10,
        num_unknown_features: 195,
        learning_rate: 0.001,
        batch_size: 32,
        dropout_rate: 0.1,
        l2_regularization: 0.0001,
        use_flash_attention: false,
        mixed_precision: false,
        memory_efficient: true,
        max_inference_latency_us: 3200,
        target_throughput_pps: 10_000,
    };

    let device = Device::Cpu;
    let mut model =
        QuantizedTemporalFusionTransformer::new_with_device(config.clone(), device.clone())?;

    // Create input tensors
    let batch_size = 2;

    // Static features: [batch, num_static_features=20]
    let static_features =
        Tensor::randn(0f32, 1.0, (batch_size, config.num_static_features), &device)?;

    // Historical features: [batch, seq_len=60, num_unknown_features=195]
    let historical_features = Tensor::randn(
        0f32,
        1.0,
        (
            batch_size,
            config.sequence_length,
            config.num_unknown_features,
        ),
        &device,
    )?;

    // Future features: [batch, horizon=10, num_known_features=10]
    let future_features = Tensor::randn(
        0f32,
        1.0,
        (
            batch_size,
            config.prediction_horizon,
            config.num_known_features,
        ),
        &device,
    )?;

    // Initialize attention weights (required for forward pass)
    let hidden_dim = config.hidden_dim;
    let q_weight = Tensor::randn(0f32, 0.1, (hidden_dim, hidden_dim), &device)?;
    let k_weight = Tensor::randn(0f32, 0.1, (hidden_dim, hidden_dim), &device)?;
    let v_weight = Tensor::randn(0f32, 0.1, (hidden_dim, hidden_dim), &device)?;
    let o_weight = Tensor::randn(0f32, 0.1, (hidden_dim, hidden_dim), &device)?;

    let mut quantizer = Quantizer::new(
        QuantizationConfig {
            quant_type: QuantizationType::Int8,
            per_channel: false,
            symmetric: true,
            calibration_samples: None,
        },
        device.clone(),
    );

    let q_weight_int8 = quantizer.quantize_tensor(&q_weight, "q_weight")?;
    let k_weight_int8 = quantizer.quantize_tensor(&k_weight, "k_weight")?;
    let v_weight_int8 = quantizer.quantize_tensor(&v_weight, "v_weight")?;
    let o_weight_int8 = quantizer.quantize_tensor(&o_weight, "o_weight")?;

    model.initialize_attention_weights(q_weight_int8, k_weight_int8, v_weight_int8, o_weight_int8);

    // Initialize static VSN weights
    let mut static_vsn_weights = HashMap::new();
    let vsn_weight = Tensor::randn(0f32, 0.1, (hidden_dim, config.num_static_features), &device)?;
    let vsn_weight_int8 = quantizer.quantize_tensor(&vsn_weight, "static_vsn")?;
    static_vsn_weights.insert("static_vsn".to_string(), vsn_weight_int8);
    model.initialize_static_vsn_weights(static_vsn_weights);

    // Run forward pass
    let output = model.forward(&static_features, &historical_features, &future_features)?;

    // Validate output shape: [batch=2, horizon=10, quantiles=3]
    assert_eq!(
        output.dims(),
        &[batch_size, config.prediction_horizon, config.num_quantiles],
        "Output shape mismatch"
    );

    // Validate no NaN/Inf values
    let output_data = output.flatten_all()?.to_vec1::<f32>()?;
    assert!(
        output_data.iter().all(|x| x.is_finite()),
        "Output contains NaN or Inf values"
    );

    println!("✅ Forward pass test passed!");
    println!("   Output shape: {:?}", output.dims());
    println!(
        "   Output range: [{:.4}, {:.4}]",
        output_data.iter().fold(f32::INFINITY, |a, &b| a.min(b)),
        output_data.iter().fold(f32::NEG_INFINITY, |a, &b| a.max(b))
    );

    Ok(())
}

#[test]
fn test_forward_pass_with_device_mismatch() {
    let config = TFTConfig::default();
    let device = Device::Cpu;
    let mut model =
        QuantizedTemporalFusionTransformer::new_with_device(config.clone(), device.clone())
            .unwrap();

    let batch_size = 2;

    // Create inputs on correct device
    let static_features = Tensor::zeros(
        (batch_size, config.num_static_features),
        DType::F32,
        &device,
    )
    .unwrap();
    let historical_features = Tensor::zeros(
        (
            batch_size,
            config.sequence_length,
            config.num_unknown_features,
        ),
        DType::F32,
        &device,
    )
    .unwrap();
    let future_features = Tensor::zeros(
        (
            batch_size,
            config.prediction_horizon,
            config.num_known_features,
        ),
        DType::F32,
        &device,
    )
    .unwrap();

    // This should work (all on same device)
    let result = model.forward(&static_features, &historical_features, &future_features);

    // Should succeed even without weights initialized (falls back to zeros)
    assert!(
        result.is_ok(),
        "Forward pass should succeed with fallback behavior"
    );
}

#[test]
fn test_forward_pass_validates_dimensions() {
    let config = TFTConfig::default();
    let device = Device::Cpu;
    let mut model =
        QuantizedTemporalFusionTransformer::new_with_device(config.clone(), device.clone())
            .unwrap();

    let batch_size = 2;

    // Test 1: Wrong static features dimensions
    let wrong_static = Tensor::zeros((batch_size, 999), DType::F32, &device).unwrap();
    let hist = Tensor::zeros(
        (
            batch_size,
            config.sequence_length,
            config.num_unknown_features,
        ),
        DType::F32,
        &device,
    )
    .unwrap();
    let fut = Tensor::zeros(
        (
            batch_size,
            config.prediction_horizon,
            config.num_known_features,
        ),
        DType::F32,
        &device,
    )
    .unwrap();

    let result = model.forward(&wrong_static, &hist, &fut);
    assert!(
        result.is_err(),
        "Should reject wrong static feature dimensions"
    );

    // Test 2: Wrong historical features dimensions
    let stat = Tensor::zeros(
        (batch_size, config.num_static_features),
        DType::F32,
        &device,
    )
    .unwrap();
    let wrong_hist = Tensor::zeros(
        (batch_size, config.sequence_length, 999),
        DType::F32,
        &device,
    )
    .unwrap();

    let result = model.forward(&stat, &wrong_hist, &fut);
    assert!(
        result.is_err(),
        "Should reject wrong historical feature dimensions"
    );

    // Test 3: Wrong future features dimensions
    let wrong_fut = Tensor::zeros(
        (batch_size, config.prediction_horizon, 999),
        DType::F32,
        &device,
    )
    .unwrap();

    let result = model.forward(&stat, &hist, &wrong_fut);
    assert!(
        result.is_err(),
        "Should reject wrong future feature dimensions"
    );
}