//! Transformation pipeline system with declarative specifications
//!
//! Provides comprehensive data transformation capabilities.

use crate::{DataRecord, Result};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// Transformation specification
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Transformation {
    pub id: String,
    pub transform_type: TransformationType,
    pub config: HashMap<String, String>,
}

/// Types of transformations
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum TransformationType {
    Sql(String),
    Map,
    Filter,
    CustomFunction(String),
}

/// Transformation builder
pub struct TransformationBuilder {
    transformation: Transformation,
}

/// Function signature for transformations
pub type TransformFunction = fn(&DataRecord) -> Result<DataRecord>;

/// Transformation pipeline
#[derive(Debug, Default)]
pub struct TransformationPipeline {
    pub steps: Vec<Transformation>,
}

/// SQL transformation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SqlTransformation {
    pub query: String,
    pub params: HashMap<String, String>,
}

impl Transformation {
    #[must_use]
    pub fn sql(query: &str) -> Self {
        Self {
            id: uuid::Uuid::new_v4().to_string(),
            transform_type: TransformationType::Sql(query.to_string()),
            config: HashMap::new(),
        }
    }
}