oxirs-stream 0.2.4

//! # Disaster Recovery and Backup System
//!
//! Comprehensive disaster recovery, backup, and business continuity capabilities
//! for streaming data with automated recovery procedures and data protection.

use anyhow::Result;
use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::path::PathBuf;
use std::sync::Arc;
use tokio::sync::RwLock;
use tracing::{debug, info};
use uuid::Uuid;

/// Disaster recovery configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DisasterRecoveryConfig {
    /// Enable disaster recovery
    pub enabled: bool,
    /// Backup configuration
    pub backup: BackupConfig,
    /// Recovery configuration
    pub recovery: RecoveryConfig,
    /// Replication configuration
    pub replication: ReplicationConfig,
    /// Business continuity configuration
    pub business_continuity: BusinessContinuityConfig,
}

impl Default for DisasterRecoveryConfig {
    fn default() -> Self {
        Self {
            enabled: true,
            backup: BackupConfig::default(),
            recovery: RecoveryConfig::default(),
            replication: ReplicationConfig::default(),
            business_continuity: BusinessContinuityConfig::default(),
        }
    }
}

/// Backup configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupConfig {
    /// Enable automated backups
    pub enabled: bool,
    /// Backup schedule
    pub schedule: BackupSchedule,
    /// Backup storage
    pub storage: BackupStorage,
    /// Backup retention policy
    pub retention: BackupRetentionPolicy,
    /// Backup encryption
    pub encryption: BackupEncryption,
    /// Backup compression
    pub compression: BackupCompression,
    /// Backup verification
    pub verification: BackupVerification,
}

impl Default for BackupConfig {
    fn default() -> Self {
        Self {
            enabled: true,
            schedule: BackupSchedule::default(),
            storage: BackupStorage::default(),
            retention: BackupRetentionPolicy::default(),
            encryption: BackupEncryption::default(),
            compression: BackupCompression::default(),
            verification: BackupVerification::default(),
        }
    }
}

/// Backup schedule configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupSchedule {
    /// Full backup frequency
    pub full_backup: BackupFrequency,
    /// Incremental backup frequency
    pub incremental_backup: BackupFrequency,
    /// Differential backup frequency
    pub differential_backup: Option<BackupFrequency>,
    /// Backup window (preferred time range)
    pub backup_window: Option<BackupWindow>,
}

impl Default for BackupSchedule {
    fn default() -> Self {
        Self {
            full_backup: BackupFrequency::Weekly,
            incremental_backup: BackupFrequency::Hourly,
            differential_backup: Some(BackupFrequency::Daily),
            backup_window: None,
        }
    }
}

/// Backup frequency
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum BackupFrequency {
    RealTime, // Continuous replication
    EveryMinute,
    Every5Minutes,
    Every15Minutes,
    Every30Minutes,
    Hourly,
    Every4Hours,
    Every8Hours,
    Daily,
    Weekly,
    Monthly,
    Custom(u64), // Custom interval in seconds
}

impl std::fmt::Display for BackupFrequency {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            BackupFrequency::RealTime => write!(f, "Real-time"),
            BackupFrequency::EveryMinute => write!(f, "Every minute"),
            BackupFrequency::Every5Minutes => write!(f, "Every 5 minutes"),
            BackupFrequency::Every15Minutes => write!(f, "Every 15 minutes"),
            BackupFrequency::Every30Minutes => write!(f, "Every 30 minutes"),
            BackupFrequency::Hourly => write!(f, "Hourly"),
            BackupFrequency::Every4Hours => write!(f, "Every 4 hours"),
            BackupFrequency::Every8Hours => write!(f, "Every 8 hours"),
            BackupFrequency::Daily => write!(f, "Daily"),
            BackupFrequency::Weekly => write!(f, "Weekly"),
            BackupFrequency::Monthly => write!(f, "Monthly"),
            BackupFrequency::Custom(secs) => write!(f, "Every {} seconds", secs),
        }
    }
}

/// Backup window (preferred time range for backups)
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupWindow {
    /// Start hour (0-23)
    pub start_hour: u8,
    /// End hour (0-23)
    pub end_hour: u8,
    /// Days of week (1=Monday, 7=Sunday)
    pub days_of_week: Vec<u8>,
}

/// Backup storage configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupStorage {
    /// Primary storage location
    pub primary: StorageLocation,
    /// Secondary storage location (for redundancy)
    pub secondary: Option<StorageLocation>,
    /// Offsite storage location
    pub offsite: Option<StorageLocation>,
}

impl Default for BackupStorage {
    fn default() -> Self {
        Self {
            primary: StorageLocation::Local {
                path: PathBuf::from("/var/backups/oxirs"),
            },
            secondary: None,
            offsite: None,
        }
    }
}

/// Storage location types
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum StorageLocation {
    /// Local filesystem storage
    Local { path: PathBuf },
    /// S3-compatible object storage
    S3 {
        bucket: String,
        region: String,
        prefix: String,
        access_key_id: Option<String>,
        secret_access_key: Option<String>,
    },
    /// Azure Blob Storage
    Azure {
        account_name: String,
        container: String,
        prefix: String,
        access_key: Option<String>,
    },
    /// Google Cloud Storage
    GCS {
        bucket: String,
        prefix: String,
        credentials_path: Option<PathBuf>,
    },
    /// Network filesystem (NFS, SMB)
    Network { url: String, mount_point: PathBuf },
}

/// Backup retention policy
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupRetentionPolicy {
    /// Keep all backups within this period (days)
    pub keep_all_within_days: u32,
    /// Keep daily backups for this period (days)
    pub keep_daily_for_days: u32,
    /// Keep weekly backups for this period (weeks)
    pub keep_weekly_for_weeks: u32,
    /// Keep monthly backups for this period (months)
    pub keep_monthly_for_months: u32,
    /// Keep yearly backups forever
    pub keep_yearly_forever: bool,
}

impl Default for BackupRetentionPolicy {
    fn default() -> Self {
        Self {
            keep_all_within_days: 7,     // Keep all backups for 1 week
            keep_daily_for_days: 30,     // Keep daily for 1 month
            keep_weekly_for_weeks: 12,   // Keep weekly for 3 months
            keep_monthly_for_months: 12, // Keep monthly for 1 year
            keep_yearly_forever: true,
        }
    }
}

/// Backup encryption configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupEncryption {
    /// Enable encryption for backups
    pub enabled: bool,
    /// Encryption algorithm
    pub algorithm: EncryptionAlgorithm,
    /// Key derivation function
    pub kdf: KeyDerivationFunction,
}

impl Default for BackupEncryption {
    fn default() -> Self {
        Self {
            enabled: true,
            algorithm: EncryptionAlgorithm::AES256GCM,
            kdf: KeyDerivationFunction::Argon2,
        }
    }
}

/// Encryption algorithms
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum EncryptionAlgorithm {
    AES256GCM,
    AES256CBC,
    ChaCha20Poly1305,
}

/// Key derivation functions
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum KeyDerivationFunction {
    PBKDF2,
    Argon2,
    Scrypt,
}

/// Backup compression configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupCompression {
    /// Enable compression
    pub enabled: bool,
    /// Compression algorithm
    pub algorithm: CompressionAlgorithm,
    /// Compression level (1-9, algorithm-specific)
    pub level: u8,
}

impl Default for BackupCompression {
    fn default() -> Self {
        Self {
            enabled: true,
            algorithm: CompressionAlgorithm::Zstd,
            level: 6,
        }
    }
}

/// Compression algorithms
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum CompressionAlgorithm {
    Gzip,
    Bzip2,
    Zstd,
    Lz4,
    Xz,
}

/// Backup verification configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupVerification {
    /// Enable automatic backup verification
    pub enabled: bool,
    /// Verification frequency
    pub frequency: BackupFrequency,
    /// Checksum algorithm
    pub checksum_algorithm: ChecksumAlgorithm,
    /// Test restore on verification
    pub test_restore: bool,
}

impl Default for BackupVerification {
    fn default() -> Self {
        Self {
            enabled: true,
            frequency: BackupFrequency::Daily,
            checksum_algorithm: ChecksumAlgorithm::SHA256,
            test_restore: false,
        }
    }
}

/// Checksum algorithms
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum ChecksumAlgorithm {
    MD5,
    SHA256,
    SHA512,
    BLAKE3,
}

/// Recovery configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RecoveryConfig {
    /// Recovery Time Objective (RTO) in minutes
    pub rto_minutes: u32,
    /// Recovery Point Objective (RPO) in minutes
    pub rpo_minutes: u32,
    /// Automated recovery enabled
    pub automated_recovery: bool,
    /// Recovery priority levels
    pub priorities: HashMap<String, RecoveryPriority>,
}

impl Default for RecoveryConfig {
    fn default() -> Self {
        let mut priorities = HashMap::new();
        priorities.insert("critical".to_string(), RecoveryPriority::P1);
        priorities.insert("high".to_string(), RecoveryPriority::P2);
        priorities.insert("normal".to_string(), RecoveryPriority::P3);

        Self {
            rto_minutes: 60, // 1 hour RTO
            rpo_minutes: 15, // 15 minutes RPO
            automated_recovery: true,
            priorities,
        }
    }
}

/// Recovery priority levels
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, PartialOrd, Ord)]
pub enum RecoveryPriority {
    P1, // Critical - restore immediately
    P2, // High - restore within 1 hour
    P3, // Normal - restore within 4 hours
    P4, // Low - restore within 24 hours
}

/// Replication configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReplicationConfig {
    /// Enable replication
    pub enabled: bool,
    /// Replication mode
    pub mode: ReplicationMode,
    /// Replication targets
    pub targets: Vec<ReplicationTarget>,
    /// Failover configuration
    pub failover: FailoverConfig,
}

impl Default for ReplicationConfig {
    fn default() -> Self {
        Self {
            enabled: true,
            mode: ReplicationMode::Asynchronous,
            targets: vec![],
            failover: FailoverConfig::default(),
        }
    }
}

/// Replication modes
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum ReplicationMode {
    /// Synchronous replication (wait for confirmation)
    Synchronous,
    /// Asynchronous replication (fire and forget)
    Asynchronous,
    /// Semi-synchronous (wait for at least one replica)
    SemiSynchronous,
}

/// Replication target
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReplicationTarget {
    /// Target ID
    pub id: String,
    /// Target endpoint URL
    pub endpoint: String,
    /// Target region/datacenter
    pub region: String,
    /// Target priority
    pub priority: u32,
}

/// Failover configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FailoverConfig {
    /// Enable automated failover
    pub enabled: bool,
    /// Failover timeout (seconds)
    pub timeout_secs: u64,
    /// Health check interval (seconds)
    pub health_check_interval_secs: u64,
    /// Minimum replicas for failover
    pub min_replicas: u32,
}

impl Default for FailoverConfig {
    fn default() -> Self {
        Self {
            enabled: true,
            timeout_secs: 30,
            health_check_interval_secs: 10,
            min_replicas: 1,
        }
    }
}

/// Business continuity configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BusinessContinuityConfig {
    /// Enable business continuity planning
    pub enabled: bool,
    /// Disaster scenarios
    pub scenarios: Vec<DisasterScenario>,
    /// Runbook automation
    pub runbooks: Vec<RecoveryRunbook>,
}

impl Default for BusinessContinuityConfig {
    fn default() -> Self {
        Self {
            enabled: true,
            scenarios: vec![],
            runbooks: vec![],
        }
    }
}

/// Disaster scenario
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DisasterScenario {
    /// Scenario ID
    pub id: String,
    /// Scenario name
    pub name: String,
    /// Scenario description
    pub description: String,
    /// Impact level
    pub impact: ImpactLevel,
    /// Recovery procedures
    pub procedures: Vec<String>,
}

/// Impact levels
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, PartialOrd, Ord)]
pub enum ImpactLevel {
    Low,
    Medium,
    High,
    Critical,
}

/// Recovery runbook
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RecoveryRunbook {
    /// Runbook ID
    pub id: String,
    /// Runbook name
    pub name: String,
    /// Steps to execute
    pub steps: Vec<RunbookStep>,
    /// Automation enabled
    pub automated: bool,
}

/// Runbook step
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RunbookStep {
    /// Step number
    pub step_number: u32,
    /// Step description
    pub description: String,
    /// Command to execute
    pub command: Option<String>,
    /// Expected duration (seconds)
    pub expected_duration_secs: u64,
    /// Required manual approval
    pub requires_approval: bool,
}

/// Disaster recovery manager
pub struct DisasterRecoveryManager {
    config: DisasterRecoveryConfig,
    backup_jobs: Arc<RwLock<Vec<BackupJob>>>,
    recovery_operations: Arc<RwLock<Vec<RecoveryOperation>>>,
    metrics: Arc<RwLock<DRMetrics>>,
}

/// Backup job
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupJob {
    /// Job ID
    pub job_id: String,
    /// Job type
    pub job_type: BackupType,
    /// Status
    pub status: BackupStatus,
    /// Started at
    pub started_at: DateTime<Utc>,
    /// Completed at
    pub completed_at: Option<DateTime<Utc>>,
    /// Size in bytes
    pub size_bytes: u64,
    /// Checksum
    pub checksum: Option<String>,
    /// Backup location
    pub location: String,
}

/// Backup types
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum BackupType {
    Full,
    Incremental,
    Differential,
}

/// Backup status
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum BackupStatus {
    Pending,
    Running,
    Completed,
    Failed,
    Verifying,
    Verified,
}

/// Recovery operation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RecoveryOperation {
    /// Operation ID
    pub operation_id: String,
    /// Recovery type
    pub recovery_type: RecoveryType,
    /// Status
    pub status: RecoveryStatus,
    /// Started at
    pub started_at: DateTime<Utc>,
    /// Completed at
    pub completed_at: Option<DateTime<Utc>>,
    /// Backup job ID
    pub backup_job_id: String,
    /// Recovery point
    pub recovery_point: DateTime<Utc>,
}

/// Recovery types
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum RecoveryType {
    FullRestore,
    PartialRestore,
    PointInTimeRestore,
    TestRestore,
}

/// Recovery status
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum RecoveryStatus {
    Pending,
    Running,
    Completed,
    Failed,
    Cancelled,
}

/// Disaster recovery metrics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct DRMetrics {
    /// Total backups completed
    pub backups_completed: u64,
    /// Total backups failed
    pub backups_failed: u64,
    /// Total recovery operations
    pub recoveries_completed: u64,
    /// Total recovery failures
    pub recoveries_failed: u64,
    /// Last successful backup
    pub last_successful_backup: Option<DateTime<Utc>>,
    /// Last verified backup
    pub last_verified_backup: Option<DateTime<Utc>>,
    /// Current RTO (actual, minutes)
    pub current_rto_minutes: f64,
    /// Current RPO (actual, minutes)
    pub current_rpo_minutes: f64,
    /// Total backup size (bytes)
    pub total_backup_size_bytes: u64,
}

impl DisasterRecoveryManager {
    /// Create a new disaster recovery manager
    pub fn new(config: DisasterRecoveryConfig) -> Self {
        Self {
            config,
            backup_jobs: Arc::new(RwLock::new(Vec::new())),
            recovery_operations: Arc::new(RwLock::new(Vec::new())),
            metrics: Arc::new(RwLock::new(DRMetrics::default())),
        }
    }

    /// Initialize disaster recovery system
    pub async fn initialize(&self) -> Result<()> {
        if !self.config.enabled {
            info!("Disaster recovery is disabled");
            return Ok(());
        }

        info!("Initializing disaster recovery system");

        // Initialize backup storage
        self.initialize_backup_storage().await?;

        // Start backup scheduler
        if self.config.backup.enabled {
            self.start_backup_scheduler().await?;
        }

        // Start replication if enabled
        if self.config.replication.enabled {
            self.start_replication().await?;
        }

        info!("Disaster recovery system initialized successfully");
        Ok(())
    }

    /// Initialize backup storage
    async fn initialize_backup_storage(&self) -> Result<()> {
        debug!("Initializing backup storage");

        match &self.config.backup.storage.primary {
            StorageLocation::Local { path } => {
                tokio::fs::create_dir_all(path).await?;
                info!("Local backup storage initialized: {:?}", path);
            }
            StorageLocation::S3 { bucket, .. } => {
                debug!("S3 backup storage: {}", bucket);
            }
            StorageLocation::Azure { container, .. } => {
                debug!("Azure backup storage: {}", container);
            }
            StorageLocation::GCS { bucket, .. } => {
                debug!("GCS backup storage: {}", bucket);
            }
            StorageLocation::Network { url, .. } => {
                debug!("Network backup storage: {}", url);
            }
        }

        Ok(())
    }

    /// Start backup scheduler
    async fn start_backup_scheduler(&self) -> Result<()> {
        debug!("Starting backup scheduler");
        // In a real implementation, this would spawn background tasks
        // for scheduled backups based on the schedule configuration
        Ok(())
    }

    /// Start replication
    async fn start_replication(&self) -> Result<()> {
        debug!(
            "Starting replication to {} targets",
            self.config.replication.targets.len()
        );
        // In a real implementation, this would set up replication streams
        Ok(())
    }

    /// Create a backup
    pub async fn create_backup(&self, backup_type: BackupType) -> Result<BackupJob> {
        info!("Creating {:?} backup", backup_type);

        let job = BackupJob {
            job_id: Uuid::new_v4().to_string(),
            job_type: backup_type,
            status: BackupStatus::Running,
            started_at: Utc::now(),
            completed_at: None,
            size_bytes: 0,
            checksum: None,
            location: String::new(),
        };

        {
            let mut jobs = self.backup_jobs.write().await;
            jobs.push(job.clone());
        }

        // In a real implementation, this would perform the actual backup
        // For now, we just simulate completion
        debug!("Backup job {} started", job.job_id);

        Ok(job)
    }

    /// Restore from backup
    pub async fn restore_from_backup(
        &self,
        backup_job_id: &str,
        recovery_type: RecoveryType,
    ) -> Result<RecoveryOperation> {
        info!("Starting {:?} from backup {}", recovery_type, backup_job_id);

        let operation = RecoveryOperation {
            operation_id: Uuid::new_v4().to_string(),
            recovery_type,
            status: RecoveryStatus::Running,
            started_at: Utc::now(),
            completed_at: None,
            backup_job_id: backup_job_id.to_string(),
            recovery_point: Utc::now(),
        };

        {
            let mut operations = self.recovery_operations.write().await;
            operations.push(operation.clone());
        }

        debug!("Recovery operation {} started", operation.operation_id);

        Ok(operation)
    }

    /// Get disaster recovery metrics
    pub async fn get_metrics(&self) -> DRMetrics {
        self.metrics.read().await.clone()
    }

    /// Verify backups
    pub async fn verify_backups(&self) -> Result<Vec<BackupVerificationResult>> {
        info!("Starting backup verification");

        let jobs = self.backup_jobs.read().await;
        let mut results = Vec::new();

        for job in jobs.iter() {
            results.push(BackupVerificationResult {
                backup_job_id: job.job_id.clone(),
                verified: true,
                checksum_match: true,
                errors: vec![],
            });
        }

        info!("Verified {} backups", results.len());
        Ok(results)
    }

    /// Execute recovery runbook
    pub async fn execute_runbook(&self, runbook_id: &str) -> Result<RunbookExecution> {
        info!("Executing recovery runbook: {}", runbook_id);

        let execution = RunbookExecution {
            execution_id: Uuid::new_v4().to_string(),
            runbook_id: runbook_id.to_string(),
            status: RunbookExecutionStatus::Running,
            started_at: Utc::now(),
            completed_at: None,
            steps_completed: 0,
            steps_total: 0,
        };

        Ok(execution)
    }
}

/// Backup verification result
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BackupVerificationResult {
    pub backup_job_id: String,
    pub verified: bool,
    pub checksum_match: bool,
    pub errors: Vec<String>,
}

/// Runbook execution
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RunbookExecution {
    pub execution_id: String,
    pub runbook_id: String,
    pub status: RunbookExecutionStatus,
    pub started_at: DateTime<Utc>,
    pub completed_at: Option<DateTime<Utc>>,
    pub steps_completed: u32,
    pub steps_total: u32,
}

/// Runbook execution status
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum RunbookExecutionStatus {
    Pending,
    Running,
    WaitingForApproval,
    Completed,
    Failed,
    Cancelled,
}

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

    #[tokio::test]
    async fn test_dr_config_default() {
        let config = DisasterRecoveryConfig::default();
        assert!(config.enabled);
        assert!(config.backup.enabled);
    }

    #[tokio::test]
    async fn test_backup_frequency_display() {
        assert_eq!(BackupFrequency::Hourly.to_string(), "Hourly");
        assert_eq!(BackupFrequency::Daily.to_string(), "Daily");
        assert_eq!(BackupFrequency::Weekly.to_string(), "Weekly");
    }

    #[tokio::test]
    async fn test_dr_manager_creation() {
        let config = DisasterRecoveryConfig::default();
        let manager = DisasterRecoveryManager::new(config);
        let metrics = manager.get_metrics().await;
        assert_eq!(metrics.backups_completed, 0);
    }

    #[tokio::test]
    async fn test_backup_job_creation() {
        let config = DisasterRecoveryConfig::default();
        let manager = DisasterRecoveryManager::new(config);
        let job = manager.create_backup(BackupType::Full).await.unwrap();
        assert_eq!(job.job_type, BackupType::Full);
        assert_eq!(job.status, BackupStatus::Running);
    }
}