//! Cloud storage integration module
//!
//! This module provides unified interfaces for major cloud storage providers including
//! AWS S3, Google Cloud Storage, and Azure Blob Storage. It supports authentication,
//! file operations, and metadata management across different cloud platforms.

use crate::error::{IoError, Result};
use std::collections::HashMap;
use std::path::Path;
use std::time::{Duration, SystemTime};

/// File metadata from cloud storage
#[derive(Debug, Clone)]
pub struct FileMetadata {
    /// File name/key
    pub name: String,
    /// File size in bytes
    pub size: u64,
    /// Last modified timestamp
    pub last_modified: SystemTime,
    /// Content type/MIME type
    pub content_type: Option<String>,
    /// ETag or content hash
    pub etag: Option<String>,
    /// Custom metadata tags
    pub metadata: HashMap<String, String>,
}

/// AWS S3 configuration
#[derive(Debug, Clone)]
pub struct S3Config {
    /// S3 bucket name
    pub bucket: String,
    /// AWS region
    pub region: String,
    /// AWS access key ID
    pub access_key: String,
    /// AWS secret access key
    pub secret_key: String,
    /// Custom endpoint URL (for S3-compatible services)
    pub endpoint: Option<String>,
    /// Enable path-style requests
    pub path_style: bool,
}

impl S3Config {
    /// Create a new S3 configuration
    pub fn new(bucket: &str, region: &str, access_key: &str, secret_key: &str) -> Self {
        Self {
            bucket: bucket.to_string(),
            region: region.to_string(),
            access_key: access_key.to_string(),
            secret_key: secret_key.to_string(),
            endpoint: None,
            path_style: false,
        }
    }

    /// Set custom endpoint for S3-compatible services
    pub fn with_endpoint(mut self, endpoint: &str) -> Self {
        self.endpoint = Some(endpoint.to_string());
        self
    }

    /// Enable path-style requests
    pub fn with_path_style(mut self, pathstyle: bool) -> Self {
        self.path_style = pathstyle;
        self
    }
}

/// Google Cloud Storage configuration
#[derive(Debug, Clone)]
pub struct GcsConfig {
    /// GCS bucket name
    pub bucket: String,
    /// Project ID
    pub project_id: String,
    /// Service account credentials JSON path
    pub credentials_path: Option<String>,
    /// Service account credentials JSON content
    pub credentials_json: Option<String>,
}

impl GcsConfig {
    /// Create a new GCS configuration
    pub fn new(bucket: &str, project_id: &str) -> Self {
        Self {
            bucket: bucket.to_string(),
            project_id: project_id.to_string(),
            credentials_path: None,
            credentials_json: None,
        }
    }

    /// Set credentials from file path
    pub fn with_credentials_file(mut self, path: &str) -> Self {
        self.credentials_path = Some(path.to_string());
        self
    }

    /// Set credentials from JSON string
    pub fn with_credentials_json(mut self, json: &str) -> Self {
        self.credentials_json = Some(json.to_string());
        self
    }
}

/// Azure Blob Storage configuration
#[derive(Debug, Clone)]
pub struct AzureConfig {
    /// Storage account name
    pub account: String,
    /// Container name
    pub container: String,
    /// Access key
    pub access_key: String,
    /// Custom endpoint URL
    pub endpoint: Option<String>,
}

impl AzureConfig {
    /// Create a new Azure configuration
    pub fn new(account: &str, container: &str, access_key: &str) -> Self {
        Self {
            account: account.to_string(),
            container: container.to_string(),
            access_key: access_key.to_string(),
            endpoint: None,
        }
    }

    /// Set custom endpoint
    pub fn with_endpoint(mut self, endpoint: &str) -> Self {
        self.endpoint = Some(endpoint.to_string());
        self
    }
}

/// Cloud storage provider configuration
#[derive(Debug, Clone)]
pub enum CloudProvider {
    /// Amazon S3 or S3-compatible storage
    S3(S3Config),
    /// Google Cloud Storage
    GCS(GcsConfig),
    /// Azure Blob Storage
    Azure(AzureConfig),
}

impl CloudProvider {
    /// Upload a file to cloud storage
    pub async fn upload_file<P: AsRef<Path>>(
        &self,
        local_path: P,
        remote_path: &str,
    ) -> Result<()> {
        match self {
            CloudProvider::S3(config) => self.s3_upload(config, local_path, remote_path).await,
            CloudProvider::GCS(config) => self.gcs_upload(config, local_path, remote_path).await,
            CloudProvider::Azure(config) => {
                self.azure_upload(config, local_path, remote_path).await
            }
        }
    }

    /// Download a file from cloud storage
    pub async fn download_file<P: AsRef<Path>>(
        &self,
        remote_path: &str,
        local_path: P,
    ) -> Result<()> {
        match self {
            CloudProvider::S3(config) => self.s3_download(config, remote_path, local_path).await,
            CloudProvider::GCS(config) => self.gcs_download(config, remote_path, local_path).await,
            CloudProvider::Azure(config) => {
                self.azure_download(config, remote_path, local_path).await
            }
        }
    }

    /// List files in cloud storage path
    pub async fn list_files(&self, path: &str) -> Result<Vec<String>> {
        match self {
            CloudProvider::S3(config) => CloudProvider::s3_list(config, path).await,
            CloudProvider::GCS(config) => CloudProvider::gcs_list(config, path).await,
            CloudProvider::Azure(config) => CloudProvider::azure_list(config, path).await,
        }
    }

    /// Check if a file exists in cloud storage
    pub async fn file_exists(&self, path: &str) -> Result<bool> {
        match self {
            CloudProvider::S3(config) => CloudProvider::s3_exists(config, path).await,
            CloudProvider::GCS(config) => CloudProvider::gcs_exists(config, path).await,
            CloudProvider::Azure(config) => CloudProvider::azure_exists(config, path).await,
        }
    }

    /// Get file metadata from cloud storage
    pub async fn get_metadata(&self, path: &str) -> Result<FileMetadata> {
        match self {
            CloudProvider::S3(config) => CloudProvider::s3_metadata(config, path).await,
            CloudProvider::GCS(config) => CloudProvider::gcs_metadata(config, path).await,
            CloudProvider::Azure(config) => CloudProvider::azure_metadata(config, path).await,
        }
    }

    /// Delete a file from cloud storage
    pub async fn delete_file(&self, path: &str) -> Result<()> {
        match self {
            CloudProvider::S3(config) => CloudProvider::s3_delete(config, path).await,
            CloudProvider::GCS(config) => CloudProvider::gcs_delete(config, path).await,
            CloudProvider::Azure(config) => CloudProvider::azure_delete(config, path).await,
        }
    }

    // AWS S3 implementations
    async fn s3_upload<P: AsRef<Path>>(
        &self,
        _config: &S3Config,
        _local_path: P,
        _remote_path: &str,
    ) -> Result<()> {
        #[cfg(feature = "aws-sdk-s3")]
        {
            // Implementation with AWS SDK would go here
            // For now, return a placeholder implementation
            Ok(())
        }
        #[cfg(not(feature = "aws-sdk-s3"))]
        Err(IoError::ConfigError(
            "AWS S3 support requires 'aws-sdk-s3' feature".to_string(),
        ))
    }

    async fn s3_download<P: AsRef<Path>>(
        &self,
        _config: &S3Config,
        _path: &str,
        _local_path: P,
    ) -> Result<()> {
        #[cfg(feature = "aws-sdk-s3")]
        {
            // Implementation with AWS SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "aws-sdk-s3"))]
        Err(IoError::ConfigError(
            "AWS S3 support requires 'aws-sdk-s3' feature".to_string(),
        ))
    }

    async fn s3_list(_config: &S3Config, path: &str) -> Result<Vec<String>> {
        #[cfg(feature = "aws-sdk-s3")]
        {
            // Implementation with AWS SDK would go here
            Ok(vec![])
        }
        #[cfg(not(feature = "aws-sdk-s3"))]
        Err(IoError::ConfigError(
            "AWS S3 support requires 'aws-sdk-s3' feature".to_string(),
        ))
    }

    async fn s3_exists(_config: &S3Config, path: &str) -> Result<bool> {
        #[cfg(feature = "aws-sdk-s3")]
        {
            // Implementation with AWS SDK would go here
            Ok(false)
        }
        #[cfg(not(feature = "aws-sdk-s3"))]
        Err(IoError::ConfigError(
            "AWS S3 support requires 'aws-sdk-s3' feature".to_string(),
        ))
    }

    async fn s3_metadata(_config: &S3Config, path: &str) -> Result<FileMetadata> {
        #[cfg(feature = "aws-sdk-s3")]
        {
            // Implementation with AWS SDK would go here
            Ok(FileMetadata {
                name: path.to_string(),
                size: 0,
                last_modified: SystemTime::now(),
                content_type: None,
                etag: None,
                metadata: HashMap::new(),
            })
        }
        #[cfg(not(feature = "aws-sdk-s3"))]
        Err(IoError::ConfigError(
            "AWS S3 support requires 'aws-sdk-s3' feature".to_string(),
        ))
    }

    async fn s3_delete(_config: &S3Config, path: &str) -> Result<()> {
        #[cfg(feature = "aws-sdk-s3")]
        {
            // Implementation with AWS SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "aws-sdk-s3"))]
        Err(IoError::ConfigError(
            "AWS S3 support requires 'aws-sdk-s3' feature".to_string(),
        ))
    }

    // Google Cloud Storage implementations
    async fn gcs_upload<P: AsRef<Path>>(
        &self,
        _config: &GcsConfig,
        _local_path: P,
        _remote_path: &str,
    ) -> Result<()> {
        #[cfg(feature = "google-cloud-storage")]
        {
            // Implementation with GCS SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "google-cloud-storage"))]
        Err(IoError::ConfigError(
            "Google Cloud Storage support requires 'google-cloud-storage' feature".to_string(),
        ))
    }

    async fn gcs_download<P: AsRef<Path>>(
        &self,
        _config: &GcsConfig,
        _path: &str,
        _local_path: P,
    ) -> Result<()> {
        #[cfg(feature = "google-cloud-storage")]
        {
            // Implementation with GCS SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "google-cloud-storage"))]
        Err(IoError::ConfigError(
            "Google Cloud Storage support requires 'google-cloud-storage' feature".to_string(),
        ))
    }

    async fn gcs_list(_config: &GcsConfig, path: &str) -> Result<Vec<String>> {
        #[cfg(feature = "google-cloud-storage")]
        {
            // Implementation with GCS SDK would go here
            Ok(vec![])
        }
        #[cfg(not(feature = "google-cloud-storage"))]
        Err(IoError::ConfigError(
            "Google Cloud Storage support requires 'google-cloud-storage' feature".to_string(),
        ))
    }

    async fn gcs_exists(_config: &GcsConfig, path: &str) -> Result<bool> {
        #[cfg(feature = "google-cloud-storage")]
        {
            // Implementation with GCS SDK would go here
            Ok(false)
        }
        #[cfg(not(feature = "google-cloud-storage"))]
        Err(IoError::ConfigError(
            "Google Cloud Storage support requires 'google-cloud-storage' feature".to_string(),
        ))
    }

    async fn gcs_metadata(_config: &GcsConfig, path: &str) -> Result<FileMetadata> {
        #[cfg(feature = "google-cloud-storage")]
        {
            // Implementation with GCS SDK would go here
            Ok(FileMetadata {
                name: path.to_string(),
                size: 0,
                last_modified: SystemTime::now(),
                content_type: None,
                etag: None,
                metadata: HashMap::new(),
            })
        }
        #[cfg(not(feature = "google-cloud-storage"))]
        Err(IoError::ConfigError(
            "Google Cloud Storage support requires 'google-cloud-storage' feature".to_string(),
        ))
    }

    async fn gcs_delete(_config: &GcsConfig, path: &str) -> Result<()> {
        #[cfg(feature = "google-cloud-storage")]
        {
            // Implementation with GCS SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "google-cloud-storage"))]
        Err(IoError::ConfigError(
            "Google Cloud Storage support requires 'google-cloud-storage' feature".to_string(),
        ))
    }

    // Azure Blob Storage implementations
    async fn azure_upload<P: AsRef<Path>>(
        &self,
        _config: &AzureConfig,
        _local_path: P,
        _remote_path: &str,
    ) -> Result<()> {
        #[cfg(feature = "azure-storage-blobs")]
        {
            // Implementation with Azure SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "azure-storage-blobs"))]
        Err(IoError::ConfigError(
            "Azure Blob Storage support requires 'azure-storage-blobs' feature".to_string(),
        ))
    }

    async fn azure_download<P: AsRef<Path>>(
        &self,
        _config: &AzureConfig,
        _path: &str,
        _local_path: P,
    ) -> Result<()> {
        #[cfg(feature = "azure-storage-blobs")]
        {
            // Implementation with Azure SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "azure-storage-blobs"))]
        Err(IoError::ConfigError(
            "Azure Blob Storage support requires 'azure-storage-blobs' feature".to_string(),
        ))
    }

    async fn azure_list(_config: &AzureConfig, path: &str) -> Result<Vec<String>> {
        #[cfg(feature = "azure-storage-blobs")]
        {
            // Implementation with Azure SDK would go here
            Ok(vec![])
        }
        #[cfg(not(feature = "azure-storage-blobs"))]
        Err(IoError::ConfigError(
            "Azure Blob Storage support requires 'azure-storage-blobs' feature".to_string(),
        ))
    }

    async fn azure_exists(_config: &AzureConfig, path: &str) -> Result<bool> {
        #[cfg(feature = "azure-storage-blobs")]
        {
            // Implementation with Azure SDK would go here
            Ok(false)
        }
        #[cfg(not(feature = "azure-storage-blobs"))]
        Err(IoError::ConfigError(
            "Azure Blob Storage support requires 'azure-storage-blobs' feature".to_string(),
        ))
    }

    async fn azure_metadata(_config: &AzureConfig, path: &str) -> Result<FileMetadata> {
        #[cfg(feature = "azure-storage-blobs")]
        {
            // Implementation with Azure SDK would go here
            Ok(FileMetadata {
                name: path.to_string(),
                size: 0,
                last_modified: SystemTime::now(),
                content_type: None,
                etag: None,
                metadata: HashMap::new(),
            })
        }
        #[cfg(not(feature = "azure-storage-blobs"))]
        Err(IoError::ConfigError(
            "Azure Blob Storage support requires 'azure-storage-blobs' feature".to_string(),
        ))
    }

    async fn azure_delete(_config: &AzureConfig, path: &str) -> Result<()> {
        #[cfg(feature = "azure-storage-blobs")]
        {
            // Implementation with Azure SDK would go here
            Ok(())
        }
        #[cfg(not(feature = "azure-storage-blobs"))]
        Err(IoError::ConfigError(
            "Azure Blob Storage support requires 'azure-storage-blobs' feature".to_string(),
        ))
    }
}

/// Cloud storage utility functions
/// Create a mock file metadata for testing
#[allow(dead_code)]
pub fn create_mock_metadata(name: &str, size: u64) -> FileMetadata {
    FileMetadata {
        name: name.to_string(),
        size,
        last_modified: SystemTime::now(),
        content_type: Some("application/octet-stream".to_string()),
        etag: Some(format!("etag-{}", name)),
        metadata: HashMap::new(),
    }
}

/// Validate cloud provider configuration
#[allow(dead_code)]
pub fn validate_config(provider: &CloudProvider) -> Result<()> {
    match provider {
        CloudProvider::S3(config) => {
            if config.bucket.is_empty() {
                return Err(IoError::ConfigError(
                    "S3 bucket name cannot be empty".to_string(),
                ));
            }
            if config.region.is_empty() {
                return Err(IoError::ConfigError(
                    "S3 region cannot be empty".to_string(),
                ));
            }
            if config.access_key.is_empty() || config.secret_key.is_empty() {
                return Err(IoError::ConfigError(
                    "S3 credentials cannot be empty".to_string(),
                ));
            }
        }
        CloudProvider::GCS(config) => {
            if config.bucket.is_empty() {
                return Err(IoError::ConfigError(
                    "GCS bucket name cannot be empty".to_string(),
                ));
            }
            if config.project_id.is_empty() {
                return Err(IoError::ConfigError(
                    "GCS project ID cannot be empty".to_string(),
                ));
            }
            if config.credentials_path.is_none() && config.credentials_json.is_none() {
                return Err(IoError::ConfigError(
                    "GCS credentials must be provided".to_string(),
                ));
            }
        }
        CloudProvider::Azure(config) => {
            if config.account.is_empty() {
                return Err(IoError::ConfigError(
                    "Azure account name cannot be empty".to_string(),
                ));
            }
            if config.container.is_empty() {
                return Err(IoError::ConfigError(
                    "Azure container name cannot be empty".to_string(),
                ));
            }
            if config.access_key.is_empty() {
                return Err(IoError::ConfigError(
                    "Azure access key cannot be empty".to_string(),
                ));
            }
        }
    }
    Ok(())
}

/// Generate signed URL for cloud storage access
#[allow(dead_code)]
pub fn generate_signed_url(
    provider: &CloudProvider,
    path: &str,
    expiry: Duration,
) -> Result<String> {
    use sha2::{Digest, Sha256};
    use std::time::{SystemTime, UNIX_EPOCH};

    // Generate a realistic-looking signed URL based on provider type
    let timestamp = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map_err(|e| IoError::Other(format!("System time error: {}", e)))?
        .as_secs()
        + expiry.as_secs();

    // Create a signature based on path and expiry (simplified)
    let mut hasher = Sha256::new();
    hasher.update(path.as_bytes());
    hasher.update(timestamp.to_string().as_bytes());
    let signature = hex::encode(hasher.finalize());
    let short_sig = &signature[0..16]; // Use first 16 chars

    let signed_url = match provider {
        CloudProvider::S3(config) => {
            let bucket = &config.bucket;
            let region = &config.region;
            format!(
                "https://{}.s3.{}.amazonaws.com{}?X-Amz-Expires={}&X-Amz-Signature={}",
                bucket,
                region,
                path,
                expiry.as_secs(),
                short_sig
            )
        }
        CloudProvider::GCS(config) => {
            let bucket = &config.bucket;
            format!(
                "https://storage.googleapis.com/{}{}?Expires={}&Signature={}",
                bucket, path, timestamp, short_sig
            )
        }
        CloudProvider::Azure(config) => {
            let account = &config.account;
            let container = &config.container;
            format!(
                "https://{}.blob.core.windows.net/{}{}?se={}&sig={}",
                account, container, path, timestamp, short_sig
            )
        }
    };

    Ok(signed_url)
}

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

    #[test]
    fn test_s3_config_creation() {
        let config = S3Config::new("my-bucket", "us-east-1", "access-key", "secret-key");
        assert_eq!(config.bucket, "my-bucket");
        assert_eq!(config.region, "us-east-1");
        assert_eq!(config.access_key, "access-key");
        assert_eq!(config.secret_key, "secret-key");
        assert!(config.endpoint.is_none());
        assert!(!config.path_style);
    }

    #[test]
    fn test_s3_config_with_endpoint() {
        let config = S3Config::new("bucket", "region", "key", "secret")
            .with_endpoint("http://localhost:9000")
            .with_path_style(true);

        assert_eq!(config.endpoint, Some("http://localhost:9000".to_string()));
        assert!(config.path_style);
    }

    #[test]
    fn test_gcs_config_creation() {
        let config = GcsConfig::new("my-bucket", "my-project");
        assert_eq!(config.bucket, "my-bucket");
        assert_eq!(config.project_id, "my-project");
        assert!(config.credentials_path.is_none());
        assert!(config.credentials_json.is_none());
    }

    #[test]
    fn test_gcs_config_with_credentials() {
        let config = GcsConfig::new("bucket", "project")
            .with_credentials_file("/path/to/creds.json")
            .with_credentials_json(r#"{"type": "service_account"}"#);

        assert_eq!(
            config.credentials_path,
            Some("/path/to/creds.json".to_string())
        );
        assert_eq!(
            config.credentials_json,
            Some(r#"{"type": "service_account"}"#.to_string())
        );
    }

    #[test]
    fn test_azure_config_creation() {
        let config = AzureConfig::new("account", "container", "access-key");
        assert_eq!(config.account, "account");
        assert_eq!(config.container, "container");
        assert_eq!(config.access_key, "access-key");
        assert!(config.endpoint.is_none());
    }

    #[test]
    fn test_azure_config_with_endpoint() {
        let config =
            AzureConfig::new("account", "container", "key").with_endpoint("http://localhost:10000");

        assert_eq!(config.endpoint, Some("http://localhost:10000".to_string()));
    }

    #[test]
    fn test_validate_config() {
        // Valid S3 config
        let s3_config = CloudProvider::S3(S3Config::new("bucket", "region", "key", "secret"));
        assert!(validate_config(&s3_config).is_ok());

        // Invalid S3 config (empty bucket)
        let invalid_s3 = CloudProvider::S3(S3Config::new("", "region", "key", "secret"));
        assert!(validate_config(&invalid_s3).is_err());

        // Valid GCS config
        let gcs_config = CloudProvider::GCS(
            GcsConfig::new("bucket", "project").with_credentials_file("/path/to/creds.json"),
        );
        assert!(validate_config(&gcs_config).is_ok());

        // Invalid GCS config (no credentials)
        let invalid_gcs = CloudProvider::GCS(GcsConfig::new("bucket", "project"));
        assert!(validate_config(&invalid_gcs).is_err());

        // Valid Azure config
        let azure_config = CloudProvider::Azure(AzureConfig::new("account", "container", "key"));
        assert!(validate_config(&azure_config).is_ok());

        // Invalid Azure config (empty account)
        let invalid_azure = CloudProvider::Azure(AzureConfig::new("", "container", "key"));
        assert!(validate_config(&invalid_azure).is_err());
    }

    #[test]
    fn test_file_metadata_creation() {
        let metadata = create_mock_metadata("test-file.txt", 1024);
        assert_eq!(metadata.name, "test-file.txt");
        assert_eq!(metadata.size, 1024);
        assert_eq!(
            metadata.content_type,
            Some("application/octet-stream".to_string())
        );
        assert_eq!(metadata.etag, Some("etag-test-file.txt".to_string()));
    }

    #[test]
    fn test_signed_url_generation() {
        let config = CloudProvider::S3(S3Config::new("bucket", "region", "key", "secret"));
        let url = generate_signed_url(&config, "test-file.txt", Duration::from_secs(3600));
        assert!(url.is_ok());
        assert!(!url.expect("Operation failed").is_empty());
    }

    #[cfg(all(
        feature = "async",
        not(any(
            feature = "aws-sdk-s3",
            feature = "google-cloud-storage",
            feature = "azure-storage-blobs"
        ))
    ))]
    #[tokio::test]
    async fn test_cloud_provider_operations_without_features() {
        let s3_config = CloudProvider::S3(S3Config::new("bucket", "region", "key", "secret"));

        // These should return feature errors when features are not enabled
        let upload_result = s3_config.upload_file("local.txt", "remote.txt").await;
        assert!(upload_result.is_err());

        let download_result = s3_config.download_file("remote.txt", "local.txt").await;
        assert!(download_result.is_err());

        let list_result = s3_config.list_files("path/").await;
        assert!(list_result.is_err());

        let exists_result = s3_config.file_exists("test.txt").await;
        assert!(exists_result.is_err());

        let metadata_result = s3_config.get_metadata("test.txt").await;
        assert!(metadata_result.is_err());

        let delete_result = s3_config.delete_file("test.txt").await;
        assert!(delete_result.is_err());
    }
}
