//! Redis configuration types
//! 
//! This module defines configuration structures for Redis connections.

use serde::{Deserialize, Serialize};
use std::time::Duration;
use crate::error::{CommonError, CommonResult};

/// Redis configuration
/// 
/// Configuration for Redis connections including connection pooling settings.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct RedisConfig {
    /// Redis connection URL
    pub url: String,
    /// Maximum number of connections in the pool
    #[serde(default = "default_max_connections")]
    pub max_connections: u32,
    /// Connection timeout
    #[serde(with = "duration_secs", default = "default_connection_timeout")]
    pub connection_timeout: Duration,
    /// Command timeout
    #[serde(with = "duration_secs", default = "default_command_timeout")]
    pub command_timeout: Duration,
    /// Enable connection keepalive
    #[serde(default = "default_true")]
    pub keepalive: bool,
    /// Database number (0-15)
    #[serde(default = "default_db")]
    pub db: u8,
    /// Password for authentication (optional)
    #[serde(skip_serializing_if = "Option::is_none")]
    pub password: Option<String>,
    /// Username for authentication (optional)
    #[serde(skip_serializing_if = "Option::is_none")]
    pub username: Option<String>,
}

fn default_max_connections() -> u32 {
    10
}

fn default_connection_timeout() -> Duration {
    Duration::from_secs(5)
}

fn default_command_timeout() -> Duration {
    Duration::from_secs(3)
}

fn default_true() -> bool {
    true
}

fn default_db() -> u8 {
    0
}

/// Serialize/Deserialize Duration as seconds
mod duration_secs {
    use serde::{Deserialize, Deserializer, Serializer};
    use std::time::Duration;

    pub fn serialize<S>(duration: &Duration, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_u64(duration.as_secs())
    }

    pub fn deserialize<'de, D>(deserializer: D) -> Result<Duration, D::Error>
    where
        D: Deserializer<'de>,
    {
        let secs = u64::deserialize(deserializer)?;
        Ok(Duration::from_secs(secs))
    }
}

impl Default for RedisConfig {
    fn default() -> Self {
        Self {
            url: "redis://localhost:6379".to_string(),
            max_connections: 10,
            connection_timeout: Duration::from_secs(5),
            command_timeout: Duration::from_secs(3),
            keepalive: true,
            db: 0,
            password: None,
            username: None,
        }
    }
}

impl RedisConfig {
    /// Create a new Redis configuration
    pub fn new(url: String) -> Self {
        Self {
            url,
            max_connections: 10,
            connection_timeout: Duration::from_secs(5),
            command_timeout: Duration::from_secs(3),
            keepalive: true,
            db: 0,
            password: None,
            username: None,
        }
    }

    /// Validate the Redis configuration
    pub fn validate(&self) -> CommonResult<()> {
        if self.url.is_empty() {
            return Err(CommonError::ValidationError(
                "Redis URL cannot be empty".to_string()
            ));
        }

        if !self.url.starts_with("redis://") && !self.url.starts_with("rediss://") {
            return Err(CommonError::ValidationError(
                "Redis URL must start with redis:// or rediss://".to_string()
            ));
        }

        if self.max_connections == 0 {
            return Err(CommonError::ValidationError(
                "Max connections must be greater than 0".to_string()
            ));
        }

        if self.db > 15 {
            return Err(CommonError::ValidationError(
                "Database number must be between 0 and 15".to_string()
            ));
        }

        if self.connection_timeout.as_secs() == 0 {
            return Err(CommonError::ValidationError(
                "Connection timeout must be greater than 0".to_string()
            ));
        }

        Ok(())
    }

    /// Get the host from the URL
    pub fn host(&self) -> Option<String> {
        self.url
            .strip_prefix("redis://")
            .or_else(|| self.url.strip_prefix("rediss://"))
            .and_then(|s| {
                // Remove user:password@ if present
                let s = if s.contains('@') {
                    s.split('@').nth(1).unwrap_or(s)
                } else {
                    s
                };
                // Extract host:port
                s.split('/').next().map(|s| {
                    if s.contains(':') {
                        s.split(':').next().unwrap_or(s).to_string()
                    } else {
                        s.to_string()
                    }
                })
            })
    }

    /// Get the port from the URL
    pub fn port(&self) -> Option<u16> {
        self.url
            .strip_prefix("redis://")
            .or_else(|| self.url.strip_prefix("rediss://"))
            .and_then(|s| {
                let s = if s.contains('@') {
                    s.split('@').nth(1).unwrap_or(s)
                } else {
                    s
                };
                s.split('/').next().and_then(|s| {
                    if s.contains(':') {
                        s.split(':').nth(1).and_then(|p| p.parse().ok())
                    } else {
                        None
                    }
                })
            })
            .or(Some(6379)) // Default Redis port
    }

    /// Check if SSL/TLS is enabled
    pub fn is_ssl(&self) -> bool {
        self.url.starts_with("rediss://")
    }
}

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

    #[test]
    fn test_redis_config_default() {
        let config = RedisConfig::default();
        assert!(!config.url.is_empty());
        assert_eq!(config.max_connections, 10);
        assert_eq!(config.db, 0);
        assert!(config.keepalive);
    }

    #[test]
    fn test_redis_config_new() {
        let config = RedisConfig::new("redis://localhost:6379".to_string());
        assert_eq!(config.url, "redis://localhost:6379");
        assert_eq!(config.max_connections, 10);
        assert_eq!(config.db, 0);
    }

    #[test]
    fn test_redis_config_validate_success() {
        let config = RedisConfig::new("redis://localhost:6379".to_string());
        assert!(config.validate().is_ok());
    }

    #[test]
    fn test_redis_config_validate_empty_url() {
        let mut config = RedisConfig::default();
        config.url = "".to_string();
        assert!(config.validate().is_err());
    }

    #[test]
    fn test_redis_config_validate_invalid_url() {
        let config = RedisConfig::new("http://localhost:6379".to_string());
        assert!(config.validate().is_err());
    }

    #[test]
    fn test_redis_config_validate_zero_max_connections() {
        let mut config = RedisConfig::new("redis://localhost:6379".to_string());
        config.max_connections = 0;
        assert!(config.validate().is_err());
    }

    #[test]
    fn test_redis_config_validate_db_too_large() {
        let mut config = RedisConfig::new("redis://localhost:6379".to_string());
        config.db = 16;
        assert!(config.validate().is_err());
    }

    #[test]
    fn test_redis_config_host() {
        let config = RedisConfig::new("redis://localhost:6379".to_string());
        assert_eq!(config.host(), Some("localhost".to_string()));
    }

    #[test]
    fn test_redis_config_host_with_auth() {
        let config = RedisConfig::new("redis://user:pass@localhost:6379".to_string());
        assert_eq!(config.host(), Some("localhost".to_string()));
    }

    #[test]
    fn test_redis_config_port() {
        let config = RedisConfig::new("redis://localhost:6380".to_string());
        assert_eq!(config.port(), Some(6380));
    }

    #[test]
    fn test_redis_config_port_default() {
        let config = RedisConfig::new("redis://localhost".to_string());
        assert_eq!(config.port(), Some(6379));
    }

    #[test]
    fn test_redis_config_is_ssl() {
        let config_ssl = RedisConfig::new("rediss://localhost:6379".to_string());
        assert!(config_ssl.is_ssl());

        let config_no_ssl = RedisConfig::new("redis://localhost:6379".to_string());
        assert!(!config_no_ssl.is_ssl());
    }

    #[test]
    fn test_redis_config_serialize() {
        let config = RedisConfig::default();
        let json = serde_json::to_string(&config).unwrap();
        assert!(json.contains("url"));
        assert!(json.contains("max_connections"));
        assert!(!json.contains("password")); // Should be skipped if None
    }

    #[test]
    fn test_redis_config_deserialize() {
        let json = r#"{
            "url": "redis://localhost:6379",
            "max_connections": 20,
            "db": 1
        }"#;
        let config: RedisConfig = serde_json::from_str(json).unwrap();
        assert_eq!(config.url, "redis://localhost:6379");
        assert_eq!(config.max_connections, 20);
        assert_eq!(config.db, 1);
    }

    #[test]
    fn test_redis_config_with_password() {
        let mut config = RedisConfig::new("redis://localhost:6379".to_string());
        config.password = Some("secret".to_string());
        assert_eq!(config.password, Some("secret".to_string()));
    }
}