//! Cloud storage provider implementations
//!
//! This module defines the trait and interfaces for different cloud storage providers,
//! enabling unified access across AWS S3, Google Cloud Storage, Azure Blob Storage,
//! and other cloud providers.

use crate::error::{CoreError, CoreResult};
use super::types::*;

/// Trait for cloud storage providers
pub trait CloudStorageProvider: std::fmt::Debug + Send + Sync {
    /// Get provider name
    fn name(&self) -> &str;

    /// Get provider type
    fn provider_type(&self) -> CloudProviderType;

    /// Initialize connection
    fn initialize(&mut self, config: &CloudProviderConfig) -> CoreResult<()>;

    /// Upload data
    fn upload(&self, request: &UploadRequest) -> CoreResult<UploadResponse>;

    /// Download data
    fn download(&self, request: &DownloadRequest) -> CoreResult<DownloadResponse>;

    /// Stream data
    fn stream(&self, request: &StreamRequest) -> CoreResult<Box<dyn DataStream>>;

    /// List objects
    fn list_objects(&self, request: &ListRequest) -> CoreResult<ListResponse>;

    /// Delete objects
    fn delete(&self, request: &DeleteRequest) -> CoreResult<DeleteResponse>;

    /// Get object metadata
    fn get_metadata(&self, request: &MetadataRequest) -> CoreResult<ObjectMetadata>;

    /// Check health
    fn health_check(&self) -> CoreResult<ProviderHealth>;

    /// Get cost estimation
    fn estimate_cost(&self, operation: &CostOperation) -> CoreResult<CostEstimate>;
}

/// AWS S3 provider implementation
#[derive(Debug)]
pub struct S3Provider {
    /// Provider name
    name: String,
    /// Configuration
    config: Option<CloudProviderConfig>,
    /// Connection state
    connected: bool,
}

impl S3Provider {
    /// Create a new S3 provider
    pub fn new() -> Self {
        Self {
            name: "AWS S3".to_string(),
            config: None,
            connected: false,
        }
    }
}

impl Default for S3Provider {
    fn default() -> Self {
        Self::new()
    }
}

impl CloudStorageProvider for S3Provider {
    fn name(&self) -> &str {
        &self.name
    }

    fn provider_type(&self) -> CloudProviderType {
        CloudProviderType::AmazonS3
    }

    fn initialize(&mut self, config: &CloudProviderConfig) -> CoreResult<()> {
        // Validate S3-specific configuration
        if config.provider_type != CloudProviderType::AmazonS3 {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "Invalid provider type for S3Provider".to_string()
                )
            ));
        }

        self.config = Some(config.clone());
        self.connected = true;
        Ok(())
    }

    fn upload(&self, request: &UploadRequest) -> CoreResult<UploadResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "S3Provider not initialized".to_string()
                )
            ));
        }

        // Simulate S3 upload
        Ok(UploadResponse {
            key: request.key.clone(),
            etag: format!("s3-etag-{:x}", std::ptr::addr_of!(request) as usize),
            timestamp: std::time::Instant::now(),
            final_size_bytes: request.data.len(),
            performance: TransferPerformance {
                duration: std::time::Duration::from_millis(100),
                transfer_rate_mbps: 50.0,
                retry_count: 0,
                compression_ratio: None,
                network_efficiency: 0.95,
            },
        })
    }

    fn download(&self, request: &DownloadRequest) -> CoreResult<DownloadResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "S3Provider not initialized".to_string()
                )
            ));
        }

        // Simulate S3 download
        Ok(DownloadResponse {
            key: request.key.clone(),
            data: vec![0u8; 1024], // Simulated data
            content_type: Some("application/octet-stream".to_string()),
            last_modified: Some(std::time::Instant::now()),
            etag: Some(format!("s3-etag-{}", std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap_or_default().as_nanos())),
            metadata: std::collections::HashMap::new(),
            performance: TransferPerformance {
                duration: std::time::Duration::from_millis(80),
                transfer_rate_mbps: 60.0,
                retry_count: 0,
                compression_ratio: None,
                network_efficiency: 0.95,
            },
        })
    }

    fn stream(&self, _request: &StreamRequest) -> CoreResult<Box<dyn DataStream>> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "S3Provider not initialized".to_string()
                )
            ));
        }

        // Return a basic stream implementation
        Ok(Box::new(BasicDataStream::new()))
    }

    fn list_objects(&self, request: &ListRequest) -> CoreResult<ListResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "S3Provider not initialized".to_string()
                )
            ));
        }

        // Simulate S3 list objects
        Ok(ListResponse {
            objects: vec![],
            common_prefixes: vec![],
            is_truncated: false,
            next_continuation_token: None,
        })
    }

    fn delete(&self, request: &DeleteRequest) -> CoreResult<DeleteResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "S3Provider not initialized".to_string()
                )
            ));
        }

        // Simulate S3 delete
        let deleted: Vec<DeletedObject> = request.objects.iter()
            .map(|obj| DeletedObject {
                key: obj.key.clone(),
                version_id: obj.version_id.clone(),
                delete_marker: false,
            })
            .collect();

        Ok(DeleteResponse {
            deleted,
            errors: vec![],
        })
    }

    fn get_metadata(&self, request: &MetadataRequest) -> CoreResult<ObjectMetadata> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "S3Provider not initialized".to_string()
                )
            ));
        }

        // Simulate S3 metadata
        Ok(ObjectMetadata {
            key: request.key.clone(),
            size: 1024,
            content_type: Some("application/octet-stream".to_string()),
            last_modified: Some(std::time::Instant::now()),
            etag: Some(format!("s3-etag-{}", std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap_or_default().as_nanos())),
            metadata: std::collections::HashMap::new(),
            storage_class: Some(StorageClass::Standard),
            encryption: None,
        })
    }

    fn health_check(&self) -> CoreResult<ProviderHealth> {
        Ok(ProviderHealth {
            status: if self.connected { HealthStatus::Healthy } else { HealthStatus::Unhealthy },
            response_time: std::time::Duration::from_millis(50),
            error_rate: 0.01,
            available_regions: vec![
                "us-east-1".to_string(),
                "us-west-2".to_string(),
                "eu-west-1".to_string(),
            ],
            service_limits: ServiceLimits {
                max_object_size: 5_000_000_000_000, // 5TB
                max_request_rate: 3500,
                max_bandwidth_mbps: 1000.0,
                request_quotas: std::collections::HashMap::new(),
            },
        })
    }

    fn estimate_cost(&self, operation: &CostOperation) -> CoreResult<CostEstimate> {
        let storage_cost = match operation.operation_type {
            OperationType::Upload => operation.data_size_bytes as f64 * 0.023 / (1024.0 * 1024.0 * 1024.0), // $0.023/GB
            OperationType::Download => operation.data_size_bytes as f64 * 0.09 / (1024.0 * 1024.0 * 1024.0), // $0.09/GB
            OperationType::Storage => {
                let duration_months = operation.storage_duration_hours.unwrap_or(0) as f64 / (24.0 * 30.0);
                operation.data_size_bytes as f64 * 0.023 / (1024.0 * 1024.0 * 1024.0) * duration_months
            },
            _ => 0.001, // Base cost for other operations
        };

        let mut breakdown = std::collections::HashMap::new();
        breakdown.insert("storage".to_string(), storage_cost);

        Ok(CostEstimate {
            total_cost: storage_cost,
            currency: "USD".to_string(),
            breakdown,
            optimization_suggestions: vec![
                "Consider using Intelligent Tiering for variable access patterns".to_string(),
                "Use multipart upload for large files".to_string(),
            ],
        })
    }
}

/// Google Cloud Storage provider implementation
#[derive(Debug)]
pub struct GCSProvider {
    /// Provider name
    name: String,
    /// Configuration
    config: Option<CloudProviderConfig>,
    /// Connection state
    connected: bool,
}

impl GCSProvider {
    /// Create a new GCS provider
    pub fn new() -> Self {
        Self {
            name: "Google Cloud Storage".to_string(),
            config: None,
            connected: false,
        }
    }
}

impl Default for GCSProvider {
    fn default() -> Self {
        Self::new()
    }
}

impl CloudStorageProvider for GCSProvider {
    fn name(&self) -> &str {
        &self.name
    }

    fn provider_type(&self) -> CloudProviderType {
        CloudProviderType::GoogleCloudStorage
    }

    fn initialize(&mut self, config: &CloudProviderConfig) -> CoreResult<()> {
        if config.provider_type != CloudProviderType::GoogleCloudStorage {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "Invalid provider type for GCSProvider".to_string()
                )
            ));
        }

        self.config = Some(config.clone());
        self.connected = true;
        Ok(())
    }

    fn upload(&self, request: &UploadRequest) -> CoreResult<UploadResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "GCSProvider not initialized".to_string()
                )
            ));
        }

        Ok(UploadResponse {
            key: request.key.clone(),
            etag: format!("gcs-etag-{}", std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap_or_default().as_nanos()),
            timestamp: std::time::Instant::now(),
            final_size_bytes: request.data.len(),
            performance: TransferPerformance {
                duration: std::time::Duration::from_millis(90),
                transfer_rate_mbps: 55.0,
                retry_count: 0,
                compression_ratio: None,
                network_efficiency: 0.97,
            },
        })
    }

    fn download(&self, request: &DownloadRequest) -> CoreResult<DownloadResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "GCSProvider not initialized".to_string()
                )
            ));
        }

        Ok(DownloadResponse {
            key: request.key.clone(),
            data: vec![0u8; 1024],
            content_type: Some("application/octet-stream".to_string()),
            last_modified: Some(std::time::Instant::now()),
            etag: Some(format!("gcs-etag-{}", std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap_or_default().as_nanos())),
            metadata: std::collections::HashMap::new(),
            performance: TransferPerformance {
                duration: std::time::Duration::from_millis(70),
                transfer_rate_mbps: 65.0,
                retry_count: 0,
                compression_ratio: None,
                network_efficiency: 0.97,
            },
        })
    }

    fn stream(&self, _request: &StreamRequest) -> CoreResult<Box<dyn DataStream>> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "GCSProvider not initialized".to_string()
                )
            ));
        }

        Ok(Box::new(BasicDataStream::new()))
    }

    fn list_objects(&self, _request: &ListRequest) -> CoreResult<ListResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "GCSProvider not initialized".to_string()
                )
            ));
        }

        Ok(ListResponse {
            objects: vec![],
            common_prefixes: vec![],
            is_truncated: false,
            next_continuation_token: None,
        })
    }

    fn delete(&self, request: &DeleteRequest) -> CoreResult<DeleteResponse> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "GCSProvider not initialized".to_string()
                )
            ));
        }

        let deleted: Vec<DeletedObject> = request.objects.iter()
            .map(|obj| DeletedObject {
                key: obj.key.clone(),
                version_id: obj.version_id.clone(),
                delete_marker: false,
            })
            .collect();

        Ok(DeleteResponse {
            deleted,
            errors: vec![],
        })
    }

    fn get_metadata(&self, request: &MetadataRequest) -> CoreResult<ObjectMetadata> {
        if !self.connected {
            return Err(CoreError::InvalidArgument(
                crate::error::ErrorContext::new(
                    "GCSProvider not initialized".to_string()
                )
            ));
        }

        Ok(ObjectMetadata {
            key: request.key.clone(),
            size: 1024,
            content_type: Some("application/octet-stream".to_string()),
            last_modified: Some(std::time::Instant::now()),
            etag: Some(format!("gcs-etag-{}", std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap_or_default().as_nanos())),
            metadata: std::collections::HashMap::new(),
            storage_class: Some(StorageClass::Standard),
            encryption: None,
        })
    }

    fn health_check(&self) -> CoreResult<ProviderHealth> {
        Ok(ProviderHealth {
            status: if self.connected { HealthStatus::Healthy } else { HealthStatus::Unhealthy },
            response_time: std::time::Duration::from_millis(45),
            error_rate: 0.005,
            available_regions: vec![
                "us-central1".to_string(),
                "europe-west1".to_string(),
                "asia-east1".to_string(),
            ],
            service_limits: ServiceLimits {
                max_object_size: 5_000_000_000_000, // 5TB
                max_request_rate: 5000,
                max_bandwidth_mbps: 1200.0,
                request_quotas: std::collections::HashMap::new(),
            },
        })
    }

    fn estimate_cost(&self, operation: &CostOperation) -> CoreResult<CostEstimate> {
        let storage_cost = match operation.operation_type {
            OperationType::Upload => operation.data_size_bytes as f64 * 0.020 / (1024.0 * 1024.0 * 1024.0), // $0.020/GB
            OperationType::Download => operation.data_size_bytes as f64 * 0.12 / (1024.0 * 1024.0 * 1024.0), // $0.12/GB
            OperationType::Storage => {
                let duration_months = operation.storage_duration_hours.unwrap_or(0) as f64 / (24.0 * 30.0);
                operation.data_size_bytes as f64 * 0.020 / (1024.0 * 1024.0 * 1024.0) * duration_months
            },
            _ => 0.001,
        };

        let mut breakdown = std::collections::HashMap::new();
        breakdown.insert("storage".to_string(), storage_cost);

        Ok(CostEstimate {
            total_cost: storage_cost,
            currency: "USD".to_string(),
            breakdown,
            optimization_suggestions: vec![
                "Consider using Nearline or Coldline storage for infrequent access".to_string(),
                "Enable compression for text-based content".to_string(),
            ],
        })
    }
}

/// Basic data stream implementation for testing
#[derive(Debug)]
pub struct BasicDataStream {
    position: u64,
    data: Vec<u8>,
}

impl BasicDataStream {
    pub fn new() -> Self {
        Self {
            position: 0,
            data: vec![0u8; 1024], // Simulated data
        }
    }
}

impl Default for BasicDataStream {
    fn default() -> Self {
        Self::new()
    }
}

impl DataStream for BasicDataStream {
    fn read(&mut self, buffer: &mut [u8]) -> CoreResult<usize> {
        if self.position >= self.data.len() as u64 {
            return Ok(0); // EOF
        }

        let remaining = self.data.len() as u64 - self.position;
        let to_read = std::cmp::min(buffer.len() as u64, remaining) as usize;

        buffer[..to_read].copy_from_slice(
            &self.data[self.position as usize..(self.position as usize + to_read)]
        );

        self.position += to_read as u64;
        Ok(to_read)
    }

    fn write(&mut self, data: &[u8]) -> CoreResult<usize> {
        // Extend internal buffer if needed
        let end_pos = self.position as usize + data.len();
        if end_pos > self.data.len() {
            self.data.resize(end_pos, 0);
        }

        self.data[self.position as usize..end_pos].copy_from_slice(data);
        self.position += data.len() as u64;
        Ok(data.len())
    }

    fn seek(&mut self, position: u64) -> CoreResult<u64> {
        self.position = position;
        Ok(self.position)
    }

    fn position(&self) -> u64 {
        self.position
    }

    fn size(&self) -> Option<u64> {
        Some(self.data.len() as u64)
    }

    fn close(&mut self) -> CoreResult<()> {
        // Nothing to close in this basic implementation
        Ok(())
    }
}

/// Provider factory for creating cloud storage providers
pub struct ProviderFactory;

impl ProviderFactory {
    /// Create a new provider instance based on the provider type
    pub fn create_provider(provider_type: &CloudProviderType) -> CoreResult<Box<dyn CloudStorageProvider>> {
        match provider_type {
            CloudProviderType::AmazonS3 => Ok(Box::new(S3Provider::new())),
            CloudProviderType::GoogleCloudStorage => Ok(Box::new(GCSProvider::new())),
            CloudProviderType::AzureBlobStorage => {
                // Placeholder for Azure implementation
                Err(CoreError::InvalidArgument(
                    crate::error::ErrorContext::new(
                        "Azure Blob Storage provider not yet implemented".to_string()
                    )
                ))
            },
            CloudProviderType::Custom(name) => {
                Err(CoreError::InvalidArgument(
                    crate::error::ErrorContext::new(
                        format!("Custom provider '{}' not supported", name)
                    )
                ))
            },
            _ => {
                Err(CoreError::InvalidArgument(
                    crate::error::ErrorContext::new(
                        format!("Provider type '{:?}' not yet implemented", provider_type)
                    )
                ))
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_s3_provider_creation() {
        let provider = S3Provider::new();
        assert_eq!(provider.name(), "AWS S3");
        assert_eq!(provider.provider_type(), CloudProviderType::AmazonS3);
    }

    #[test]
    fn test_gcs_provider_creation() {
        let provider = GCSProvider::new();
        assert_eq!(provider.name(), "Google Cloud Storage");
        assert_eq!(provider.provider_type(), CloudProviderType::GoogleCloudStorage);
    }

    #[test]
    fn test_provider_factory() {
        let s3_provider = ProviderFactory::create_provider(&CloudProviderType::AmazonS3);
        assert!(s3_provider.is_ok());

        let gcs_provider = ProviderFactory::create_provider(&CloudProviderType::GoogleCloudStorage);
        assert!(gcs_provider.is_ok());
    }

    #[test]
    fn test_basic_data_stream() {
        let mut stream = BasicDataStream::new();

        let mut buffer = [0u8; 10];
        let bytes_read = stream.read(&mut buffer).expect("Operation failed");
        assert_eq!(bytes_read, 10);

        let write_data = [1u8; 5];
        let bytes_written = stream.write(&write_data).expect("Operation failed");
        assert_eq!(bytes_written, 5);
    }
}