//! Worker Configuration Module - TOML-based configuration for Hero workers

use serde::{Deserialize, Serialize};
use std::fs;
use std::path::Path;
use std::time::Duration;

/// Worker configuration loaded from TOML file
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WorkerConfig {
    /// Worker identification
    pub worker_id: String,
    
    /// Redis connection URL
    pub redis_url: String,
    
    /// Database path for Rhai engine
    pub db_path: String,
    
    /// Whether to preserve task details after completion
    #[serde(default = "default_preserve_tasks")]
    pub preserve_tasks: bool,
    
    /// Worker type configuration
    pub worker_type: WorkerType,
    
    /// Logging configuration
    #[serde(default)]
    pub logging: LoggingConfig,
}

/// Worker type configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type")]
pub enum WorkerType {
    /// Synchronous worker configuration
    #[serde(rename = "sync")]
    Sync,
    
    /// Asynchronous worker configuration
    #[serde(rename = "async")]
    Async {
        /// Default timeout for jobs in seconds
        #[serde(default = "default_timeout_seconds")]
        default_timeout_seconds: u64,
    },
}

/// Logging configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LoggingConfig {
    /// Whether to include timestamps in log output
    #[serde(default = "default_timestamps")]
    pub timestamps: bool,
    
    /// Log level (trace, debug, info, warn, error)
    #[serde(default = "default_log_level")]
    pub level: String,
}

impl Default for LoggingConfig {
    fn default() -> Self {
        Self {
            timestamps: default_timestamps(),
            level: default_log_level(),
        }
    }
}

impl WorkerConfig {
    /// Load configuration from TOML file
    pub fn from_file<P: AsRef<Path>>(path: P) -> Result<Self, ConfigError> {
        let content = fs::read_to_string(&path)
            .map_err(|e| ConfigError::IoError(format!("Failed to read config file: {}", e)))?;
        
        let config: WorkerConfig = toml::from_str(&content)
            .map_err(|e| ConfigError::ParseError(format!("Failed to parse TOML: {}", e)))?;
        
        config.validate()?;
        Ok(config)
    }
    
    /// Validate the configuration
    fn validate(&self) -> Result<(), ConfigError> {
        if self.worker_id.is_empty() {
            return Err(ConfigError::ValidationError("worker_id cannot be empty".to_string()));
        }
        
        if self.redis_url.is_empty() {
            return Err(ConfigError::ValidationError("redis_url cannot be empty".to_string()));
        }
        
        if self.db_path.is_empty() {
            return Err(ConfigError::ValidationError("db_path cannot be empty".to_string()));
        }
        
        // Validate log level
        match self.logging.level.to_lowercase().as_str() {
            "trace" | "debug" | "info" | "warn" | "error" => {},
            _ => return Err(ConfigError::ValidationError(
                format!("Invalid log level: {}. Must be one of: trace, debug, info, warn, error", self.logging.level)
            )),
        }
        
        Ok(())
    }
    
    /// Get the default timeout duration for async workers
    pub fn get_default_timeout(&self) -> Option<Duration> {
        match &self.worker_type {
            WorkerType::Sync => None,
            WorkerType::Async { default_timeout_seconds } => {
                Some(Duration::from_secs(*default_timeout_seconds))
            }
        }
    }
    
    /// Check if this is a sync worker configuration
    pub fn is_sync(&self) -> bool {
        matches!(self.worker_type, WorkerType::Sync)
    }
    
    /// Check if this is an async worker configuration
    pub fn is_async(&self) -> bool {
        matches!(self.worker_type, WorkerType::Async { .. })
    }
}

/// Configuration error types
#[derive(Debug, thiserror::Error)]
pub enum ConfigError {
    #[error("IO error: {0}")]
    IoError(String),
    
    #[error("Parse error: {0}")]
    ParseError(String),
    
    #[error("Validation error: {0}")]
    ValidationError(String),
}

// Default value functions for serde
fn default_preserve_tasks() -> bool {
    false
}

fn default_timeout_seconds() -> u64 {
    300 // 5 minutes
}

fn default_timestamps() -> bool {
    true
}

fn default_log_level() -> String {
    "info".to_string()
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::io::Write;
    use tempfile::NamedTempFile;

    #[test]
    fn test_sync_worker_config() {
        let config_toml = r#"
worker_id = "sync_worker_1"
redis_url = "redis://localhost:6379"
db_path = "/tmp/worker_db"

[worker_type]
type = "sync"

[logging]
timestamps = false
level = "debug"
"#;
        
        let config: WorkerConfig = toml::from_str(config_toml).unwrap();
        assert_eq!(config.worker_id, "sync_worker_1");
        assert!(config.is_sync());
        assert!(!config.is_async());
        assert_eq!(config.get_default_timeout(), None);
        assert!(!config.logging.timestamps);
        assert_eq!(config.logging.level, "debug");
    }

    #[test]
    fn test_async_worker_config() {
        let config_toml = r#"
worker_id = "async_worker_1"
redis_url = "redis://localhost:6379"
db_path = "/tmp/worker_db"

[worker_type]
type = "async"
default_timeout_seconds = 600

[logging]
timestamps = true
level = "info"
"#;
        
        let config: WorkerConfig = toml::from_str(config_toml).unwrap();
        assert_eq!(config.worker_id, "async_worker_1");
        assert!(!config.is_sync());
        assert!(config.is_async());
        assert_eq!(config.get_default_timeout(), Some(Duration::from_secs(600)));
        assert!(config.logging.timestamps);
        assert_eq!(config.logging.level, "info");
    }

    #[test]
    fn test_config_from_file() {
        let config_toml = r#"
worker_id = "test_worker"
redis_url = "redis://localhost:6379"
db_path = "/tmp/test_db"

[worker_type]
type = "sync"
"#;
        
        let mut temp_file = NamedTempFile::new().unwrap();
        temp_file.write_all(config_toml.as_bytes()).unwrap();
        
        let config = WorkerConfig::from_file(temp_file.path()).unwrap();
        assert_eq!(config.worker_id, "test_worker");
        assert!(config.is_sync());
    }

    #[test]
    fn test_config_validation() {
        let config_toml = r#"
worker_id = ""
redis_url = "redis://localhost:6379"
db_path = "/tmp/test_db"

[worker_type]
type = "sync"
"#;
        
        let result: Result<WorkerConfig, _> = toml::from_str(config_toml);
        assert!(result.is_ok());
        
        let config = result.unwrap();
        assert!(config.validate().is_err());
    }
}