//! Integration tests for model_loader

use anyhow::Result;
use chrono::Utc;
use model_loader::{
    backtesting_cache::BacktestCacheConfig, ModelLoaderConfig, LoadedModelInfo, ModelType,
};
use parking_lot::Mutex;
use semver::Version;
use std::collections::HashMap;
use std::sync::Arc;
use std::time::{Duration, SystemTime};
use storage::{Storage, StorageMetadata};

/// Mock storage backend for testing
#[derive(Clone)]
struct MockStorage {
    data: Arc<Mutex<HashMap<String, Vec<u8>>>>,
}

impl MockStorage {
    fn new() -> Self {
        let mut data = HashMap::new();

        // Pre-populate with test data
        data.insert(
            "models/test_model/1.0.0/model.bin".to_string(),
            vec![1_u8, 2_u8, 3_u8, 4_u8, 5_u8],
        );
        data.insert(
            "models/test_model/1.1.0/model.bin".to_string(),
            vec![1_u8, 2_u8, 3_u8, 4_u8, 5_u8],
        );
        data.insert(
            "models/test_model/2.0.0/model.bin".to_string(),
            vec![1_u8, 2_u8, 3_u8, 4_u8, 5_u8],
        );

        // Add metadata
        for version_str in &["1.0.0", "1.1.0", "2.0.0"] {
            let version = Version::parse(version_str).unwrap();
            let metadata = LoadedModelInfo {
                name: "test_model".to_string(),
                version,
                model_type: ModelType::DQN,
                created_at: SystemTime::UNIX_EPOCH + Duration::from_secs(1000000),
                size_bytes: 5,
                checksum: "abc123".to_string(),
            };
            let key = format!("models/test_model/{}/metadata.json", version_str);
            data.insert(key, serde_json::to_vec(&metadata).unwrap());
        }

        Self {
            data: Arc::new(Mutex::new(data)),
        }
    }
}

#[async_trait::async_trait]
impl Storage for MockStorage {
    async fn store(&self, path: &str, data: &[u8]) -> storage::error::StorageResult<()> {
        self.data.lock().insert(path.to_string(), data.to_vec());
        Ok(())
    }

    async fn retrieve(&self, path: &str) -> storage::error::StorageResult<Vec<u8>> {
        self.data
            .lock()
            .get(path)
            .cloned()
            .ok_or_else(|| storage::error::StorageError::IoError {
                message: format!("Key not found: {}", path),
            })
    }

    async fn exists(&self, path: &str) -> storage::error::StorageResult<bool> {
        Ok(self.data.lock().contains_key(path))
    }

    async fn delete(&self, path: &str) -> storage::error::StorageResult<bool> {
        Ok(self.data.lock().remove(path).is_some())
    }

    async fn list(&self, prefix: &str) -> storage::error::StorageResult<Vec<String>> {
        let keys: Vec<String> = self
            .data
            .lock()
            .keys()
            .filter(|k| k.starts_with(prefix))
            .cloned()
            .collect();
        Ok(keys)
    }

    async fn metadata(&self, path: &str) -> storage::error::StorageResult<StorageMetadata> {
        let data = self.retrieve(path).await?;
        Ok(StorageMetadata {
            path: path.to_string(),
            size: data.len() as u64,
            content_type: Some("application/octet-stream".to_string()),
            last_modified: Utc::now(),
            etag: Some("test-etag".to_string()),
            tags: HashMap::new(),
        })
    }
}

// We can't directly create ObjectStoreBackend with MockStorage because it expects
// real S3 config. Instead, we'll test the ModelLoader interface directly.

#[tokio::test]
async fn test_model_type_s3_prefix() {
    assert_eq!(ModelType::TLOB.s3_prefix(), "tlob_transformer");
    assert_eq!(ModelType::DQN.s3_prefix(), "dqn");
    assert_eq!(ModelType::MAMBA.s3_prefix(), "mamba2");
    assert_eq!(ModelType::TFT.s3_prefix(), "tft");
    assert_eq!(ModelType::PPO.s3_prefix(), "ppo");
    assert_eq!(ModelType::LNN.s3_prefix(), "liquid");
    assert_eq!(ModelType::Ensemble.s3_prefix(), "ensemble");
}

#[tokio::test]
async fn test_model_type_as_str() {
    assert_eq!(ModelType::TLOB.as_str(), "tlob");
    assert_eq!(ModelType::DQN.as_str(), "dqn");
    assert_eq!(ModelType::MAMBA.as_str(), "mamba");
    assert_eq!(ModelType::TFT.as_str(), "tft");
    assert_eq!(ModelType::PPO.as_str(), "ppo");
    assert_eq!(ModelType::LNN.as_str(), "liquid");
    assert_eq!(ModelType::Ensemble.as_str(), "ensemble");
}

#[tokio::test]
async fn test_model_type_serialization() -> Result<()> {
    let model_type = ModelType::MAMBA;
    let json = serde_json::to_string(&model_type)?;
    let deserialized: ModelType = serde_json::from_str(&json)?;

    assert_eq!(model_type, deserialized);
    Ok(())
}

#[tokio::test]
async fn test_metadata_serialization() -> Result<()> {
    let metadata = LoadedModelInfo {
        name: "test_model".to_string(),
        version: Version::new(1, 2, 3),
        model_type: ModelType::TLOB,
        created_at: SystemTime::now(),
        size_bytes: 12345,
        checksum: "sha256:abc123".to_string(),
    };

    let json = serde_json::to_string(&metadata)?;
    let deserialized: LoadedModelInfo = serde_json::from_str(&json)?;

    assert_eq!(metadata.name, deserialized.name);
    assert_eq!(metadata.version, deserialized.version);
    assert_eq!(metadata.model_type, deserialized.model_type);
    Ok(())
}

#[test]
fn test_model_loader_config_default() {
    let config = ModelLoaderConfig::default();
    assert_eq!(config.prefix, "models/");
    assert_eq!(config.cache_size, 1000);
}

#[test]
fn test_model_type_all_variants() {
    let types = vec![
        ModelType::TLOB,
        ModelType::DQN,
        ModelType::MAMBA,
        ModelType::TFT,
        ModelType::PPO,
        ModelType::LNN,
        ModelType::Ensemble,
    ];

    for model_type in types {
        assert!(!model_type.as_str().is_empty());
    }
}

#[tokio::test]
async fn test_config_custom_values() {
    let config = ModelLoaderConfig {
        prefix: "custom/prefix/".to_string(),
        cache_size: 500,
    };

    assert_eq!(config.prefix, "custom/prefix/");
    assert_eq!(config.cache_size, 500);
}

#[tokio::test]
async fn test_backtesting_cache_config_custom() {
    let config = BacktestCacheConfig {
        cache_dir: std::path::PathBuf::from("/custom/cache"),
        model_loader_config: ModelLoaderConfig {
            prefix: "test/".to_string(),
            cache_size: 100,
        },
    };

    assert_eq!(config.cache_dir, std::path::PathBuf::from("/custom/cache"));
    assert_eq!(config.model_loader_config.prefix, "test/");
}

// Note: Integration tests with real ObjectStoreBackend require actual S3 credentials
// and are better suited for CI/CD environment with mocked S3 (like LocalStack).
// The MockStorage tests above verify the basic functionality without S3 dependency.

#[tokio::test]
async fn test_version_parsing() -> Result<()> {
    let v1 = Version::parse("1.0.0")?;
    let v2 = Version::parse("2.0.0")?;
    let v3 = Version::parse("1.1.0")?;

    assert!(v2 > v1);
    assert!(v3 > v1);
    assert!(v2 > v3);
    Ok(())
}

#[tokio::test]
async fn test_model_metadata_defaults() {
    let metadata = LoadedModelInfo {
        name: "test".to_string(),
        version: Version::new(1, 0, 0),
        model_type: ModelType::DQN,
        created_at: SystemTime::now(),
        size_bytes: 0,
        checksum: String::new(),
    };

    assert_eq!(metadata.name, "test");
    assert_eq!(metadata.version, Version::new(1, 0, 0));
}

#[tokio::test]
async fn test_cache_key_hashing() {
    use std::collections::hash_map::DefaultHasher;
    use std::hash::{Hash, Hasher};

    // Create two identical cache keys
    let key1 = ("test_model".to_string(), Version::new(1, 0, 0));
    let key2 = ("test_model".to_string(), Version::new(1, 0, 0));

    let mut hasher1 = DefaultHasher::new();
    let mut hasher2 = DefaultHasher::new();

    key1.hash(&mut hasher1);
    key2.hash(&mut hasher2);

    assert_eq!(hasher1.finish(), hasher2.finish());
}