optirs-tpu 0.3.1

use std::fmt::Debug;
// High-level operation lowering for XLA compilation
//
// This module handles the lowering of high-level operations to XLA primitives,
// including operation decomposition and primitive mapping.

use scirs2_core::numeric::Float;
use std::collections::HashMap;

use super::graph_capture::{
    DataType, OperandId, OperationId, OperationType, TensorShape, XLAComputation, XLAOperation,
};
use crate::error::{OptimError, Result};

/// Operation lowering engine
pub struct OperationLowering {
    /// Lowering rules registry
    lowering_rules: HashMap<String, LoweringRule>,

    /// Primitive operation mappings
    primitive_mappings: HashMap<OperationType, Vec<PrimitiveOperation>>,

    /// Decomposition patterns
    decomposition_patterns: Vec<DecompositionPattern>,
}

/// Lowering rule for operations
#[derive(Debug, Clone)]
pub struct LoweringRule {
    /// Rule name
    pub name: String,

    /// Source operation type
    pub source_op: String,

    /// Target primitive operations
    pub target_primitives: Vec<String>,

    /// Lowering function
    pub lowering_fn: String,

    /// Prerequisites
    pub prerequisites: Vec<String>,
}

/// Primitive operation in XLA
#[derive(Debug, Clone)]
pub struct PrimitiveOperation {
    /// Primitive name
    pub name: String,

    /// Input types
    pub input_types: Vec<DataType>,

    /// Output type
    pub output_type: DataType,

    /// Constraints
    pub constraints: Vec<OperationConstraint>,
}

/// Operation constraints
#[derive(Debug, Clone)]
pub struct OperationConstraint {
    /// Constraint type
    pub constraint_type: ConstraintType,

    /// Constraint description
    pub description: String,

    /// Constraint parameters
    pub parameters: HashMap<String, String>,
}

/// Types of operation constraints
#[derive(Debug, Clone)]
pub enum ConstraintType {
    ShapeCompatibility,
    DataTypeCompatibility,
    MemoryAlignment,
    HardwareSupport,
    PerformanceRequirement,
}

/// Decomposition pattern for complex operations
#[derive(Debug, Clone)]
pub struct DecompositionPattern {
    /// Pattern name
    pub name: String,

    /// Source operation pattern
    pub source_pattern: OperationPattern,

    /// Target operation sequence
    pub target_sequence: Vec<OperationTemplate>,

    /// Applicability conditions
    pub conditions: Vec<String>,
}

/// Operation pattern matching
#[derive(Debug, Clone)]
pub struct OperationPattern {
    /// Operation type to match
    pub op_type: OperationType,

    /// Input patterns
    pub input_patterns: Vec<OperandPattern>,

    /// Attribute patterns
    pub attribute_patterns: HashMap<String, String>,
}

/// Operand pattern for matching
#[derive(Debug, Clone)]
pub struct OperandPattern {
    /// Shape pattern
    pub shape_pattern: ShapePattern,

    /// Data type pattern
    pub dtype_pattern: Option<DataType>,

    /// Value constraints
    pub value_constraints: Vec<String>,
}

/// Shape pattern matching
#[derive(Debug, Clone)]
pub enum ShapePattern {
    Any,
    Scalar,
    Vector(Option<usize>),
    Matrix(Option<(usize, usize)>),
    Tensor(Vec<Option<usize>>),
    Broadcast,
}

/// Operation template for code generation
#[derive(Debug, Clone)]
pub struct OperationTemplate {
    /// Template operation type
    pub op_type: OperationType,

    /// Input mapping
    pub input_mapping: Vec<OperandMapping>,

    /// Output shape calculation
    pub output_shape_calc: String,

    /// Attributes
    pub attributes: HashMap<String, String>,
}

/// Operand mapping in templates
#[derive(Debug, Clone)]
pub enum OperandMapping {
    Direct(usize),        // Direct input mapping
    Constant(String),     // Constant value
    Computed(String),     // Computed from inputs
    Intermediate(String), // Intermediate result
}

/// Lowering context
#[derive(Debug)]
pub struct LoweringContext<T: Float + Debug + Send + Sync + 'static> {
    /// Current computation
    pub computation: XLAComputation<T>,

    /// Intermediate results
    pub intermediates: HashMap<String, OperandId>,

    /// Lowering options
    pub options: LoweringOptions,

    /// Target hardware capabilities
    pub hardware_caps: HardwareCapabilities,
}

/// Lowering options
#[derive(Debug, Clone, Default)]
pub struct LoweringOptions {
    /// Optimize for memory
    pub optimize_memory: bool,

    /// Optimize for compute
    pub optimize_compute: bool,

    /// Enable fusion opportunities
    pub enable_fusion: bool,

    /// Target precision
    pub target_precision: Option<DataType>,

    /// Maximum decomposition depth
    pub max_decomposition_depth: usize,
}

/// Hardware capabilities
#[derive(Debug, Clone)]
pub struct HardwareCapabilities {
    /// Supported data types
    pub supported_dtypes: Vec<DataType>,

    /// Native operations
    pub native_operations: Vec<OperationType>,

    /// Memory hierarchy
    pub memory_hierarchy: MemoryHierarchy,

    /// Compute units
    pub compute_units: ComputeUnits,
}

/// Memory hierarchy information
#[derive(Debug, Clone)]
pub struct MemoryHierarchy {
    /// L1 cache size (bytes)
    pub l1_cache_size: usize,

    /// L2 cache size (bytes)
    pub l2_cache_size: usize,

    /// HBM size (bytes)
    pub hbm_size: usize,

    /// Memory bandwidth (GB/s)
    pub memory_bandwidth: f64,
}

/// Compute unit information
#[derive(Debug, Clone)]
pub struct ComputeUnits {
    /// Number of scalar units
    pub scalar_units: usize,

    /// Number of vector units
    pub vector_units: usize,

    /// Number of matrix units
    pub matrix_units: usize,

    /// Vector width
    pub vector_width: usize,

    /// Matrix dimensions
    pub matrix_dims: (usize, usize),
}

impl Default for OperationLowering {
    fn default() -> Self {
        Self::new()
    }
}

impl OperationLowering {
    /// Create new operation lowering engine
    pub fn new() -> Self {
        let mut lowering = Self {
            lowering_rules: HashMap::new(),
            primitive_mappings: HashMap::new(),
            decomposition_patterns: Vec::new(),
        };

        lowering.initialize_builtin_rules();
        lowering
    }

    /// Initialize built-in lowering rules
    fn initialize_builtin_rules(&mut self) {
        // Add basic arithmetic operations
        self.add_primitive_mapping(
            OperationType::Add,
            vec![PrimitiveOperation {
                name: "add".to_string(),
                input_types: vec![DataType::F32, DataType::F32],
                output_type: DataType::F32,
                constraints: vec![],
            }],
        );

        self.add_primitive_mapping(
            OperationType::Multiply,
            vec![PrimitiveOperation {
                name: "multiply".to_string(),
                input_types: vec![DataType::F32, DataType::F32],
                output_type: DataType::F32,
                constraints: vec![],
            }],
        );

        // Add decomposition patterns
        self.add_decomposition_pattern(DecompositionPattern {
            name: "batch_norm_decomposition".to_string(),
            source_pattern: OperationPattern {
                op_type: OperationType::Custom(super::graph_capture::CustomOperation {
                    name: "batch_norm".to_string(),
                    custom_attributes: HashMap::new(),
                    backend_config: None,
                }),
                input_patterns: vec![],
                attribute_patterns: HashMap::new(),
            },
            target_sequence: vec![
                OperationTemplate {
                    op_type: OperationType::Subtract,
                    input_mapping: vec![OperandMapping::Direct(0), OperandMapping::Direct(1)],
                    output_shape_calc: "input_shape[0]".to_string(),
                    attributes: HashMap::new(),
                },
                OperationTemplate {
                    op_type: OperationType::Multiply,
                    input_mapping: vec![
                        OperandMapping::Intermediate("norm_sub".to_string()),
                        OperandMapping::Direct(2),
                    ],
                    output_shape_calc: "input_shape[0]".to_string(),
                    attributes: HashMap::new(),
                },
            ],
            conditions: vec!["input_rank >= 2".to_string()],
        });
    }

    /// Lower high-level operations to XLA primitives
    pub fn lower_operations<
        T: Float + Default + std::fmt::Debug + Clone + Send + Sync + 'static,
    >(
        computation: XLAComputation<T>,
    ) -> Result<XLAComputation<T>> {
        let lowering = Self::new();
        let options = LoweringOptions::default();
        let hardware_caps = HardwareCapabilities::default();

        let mut context = LoweringContext {
            computation,
            intermediates: HashMap::new(),
            options,
            hardware_caps,
        };

        lowering.lower_computation(&mut context)
    }

    /// Lower entire computation
    fn lower_computation<T: Float + Default + std::fmt::Debug + Clone + Send + Sync + 'static>(
        &self,
        context: &mut LoweringContext<T>,
    ) -> Result<XLAComputation<T>> {
        let mut new_operations = Vec::new();

        for operation in &context.computation.operations {
            let lowered_ops = self.lower_operation(operation, context)?;
            new_operations.extend(lowered_ops);
        }

        let mut new_computation = context.computation.clone();
        new_computation.operations = new_operations;

        Ok(new_computation)
    }

    /// Lower individual operation
    fn lower_operation<T: Float + Default + std::fmt::Debug + Clone + Send + Sync + 'static>(
        &self,
        operation: &XLAOperation<T>,
        context: &LoweringContext<T>,
    ) -> Result<Vec<XLAOperation<T>>> {
        // Check if operation needs lowering
        if self.is_primitive(&operation.op_type) {
            return Ok(vec![operation.clone()]);
        }

        // Apply decomposition patterns
        if let Some(pattern) = self.find_matching_pattern(&operation.op_type) {
            return self.apply_decomposition_pattern(operation, pattern, context);
        }

        // Apply primitive mapping
        if let Some(primitives) = self.primitive_mappings.get(&operation.op_type) {
            return self.apply_primitive_mapping(operation, primitives, context);
        }

        // If no lowering rule found, return original operation
        Ok(vec![operation.clone()])
    }

    /// Check if operation is already primitive
    fn is_primitive(&self, op_type: &OperationType) -> bool {
        matches!(
            op_type,
            OperationType::Add
                | OperationType::Multiply
                | OperationType::Subtract
                | OperationType::Divide
                | OperationType::Dot
                | OperationType::Reshape
                | OperationType::Transpose
        )
    }

    /// Find matching decomposition pattern
    fn find_matching_pattern(&self, op_type: &OperationType) -> Option<&DecompositionPattern> {
        self.decomposition_patterns
            .iter()
            .find(|pattern| pattern.source_pattern.op_type == *op_type)
    }

    /// Apply decomposition pattern
    fn apply_decomposition_pattern<
        T: Float + Default + std::fmt::Debug + Clone + Send + Sync + 'static,
    >(
        &self,
        operation: &XLAOperation<T>,
        pattern: &DecompositionPattern,
        context: &LoweringContext<T>,
    ) -> Result<Vec<XLAOperation<T>>> {
        let mut result_operations = Vec::new();
        let current_intermediates = context.intermediates.clone();

        for template in &pattern.target_sequence {
            let new_op = self.instantiate_template(operation, template, &current_intermediates)?;
            result_operations.push(new_op);
        }

        Ok(result_operations)
    }

    /// Apply primitive mapping
    fn apply_primitive_mapping<
        T: Float + Default + std::fmt::Debug + Clone + Send + Sync + 'static,
    >(
        &self,
        operation: &XLAOperation<T>,
        _primitives: &[PrimitiveOperation],
        _context: &LoweringContext<T>,
    ) -> Result<Vec<XLAOperation<T>>> {
        // Simplified primitive mapping
        Ok(vec![operation.clone()])
    }

    /// Instantiate operation template
    fn instantiate_template<
        T: Float + Default + std::fmt::Debug + Clone + Send + Sync + 'static,
    >(
        &self,
        source_op: &XLAOperation<T>,
        template: &OperationTemplate,
        _intermediates: &HashMap<String, OperandId>,
    ) -> Result<XLAOperation<T>> {
        let mut new_op = source_op.clone();
        new_op.op_type = template.op_type.clone();

        // Map inputs according to template
        let mut new_inputs = Vec::new();
        for mapping in &template.input_mapping {
            match mapping {
                OperandMapping::Direct(idx) => {
                    if *idx < source_op.inputs.len() {
                        new_inputs.push(source_op.inputs[*idx]);
                    }
                }
                OperandMapping::Constant(_) => {
                    // Would create constant operand
                    if !source_op.inputs.is_empty() {
                        new_inputs.push(source_op.inputs[0]);
                    }
                }
                OperandMapping::Computed(_) => {
                    // Would compute new operand
                    if !source_op.inputs.is_empty() {
                        new_inputs.push(source_op.inputs[0]);
                    }
                }
                OperandMapping::Intermediate(_) => {
                    // Would use intermediate result
                    if !source_op.inputs.is_empty() {
                        new_inputs.push(source_op.inputs[0]);
                    }
                }
            }
        }

        new_op.inputs = new_inputs;
        Ok(new_op)
    }

    /// Add primitive mapping
    fn add_primitive_mapping(
        &mut self,
        op_type: OperationType,
        primitives: Vec<PrimitiveOperation>,
    ) {
        self.primitive_mappings.insert(op_type, primitives);
    }

    /// Add decomposition pattern
    fn add_decomposition_pattern(&mut self, pattern: DecompositionPattern) {
        self.decomposition_patterns.push(pattern);
    }
}

impl Default for HardwareCapabilities {
    fn default() -> Self {
        Self {
            supported_dtypes: vec![DataType::F32, DataType::BF16, DataType::S32],
            native_operations: vec![
                OperationType::Add,
                OperationType::Multiply,
                OperationType::Dot,
                OperationType::Reshape,
                OperationType::Transpose,
            ],
            memory_hierarchy: MemoryHierarchy {
                l1_cache_size: 1024 * 1024,        // 1 MB
                l2_cache_size: 32 * 1024 * 1024,   // 32 MB
                hbm_size: 32 * 1024 * 1024 * 1024, // 32 GB
                memory_bandwidth: 1600.0,          // 1.6 TB/s
            },
            compute_units: ComputeUnits {
                scalar_units: 128,
                vector_units: 64,
                matrix_units: 4,
                vector_width: 256,
                matrix_dims: (128, 128),
            },
        }
    }
}

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

    #[test]
    fn test_operation_lowering_creation() {
        let lowering = OperationLowering::new();
        assert!(!lowering.primitive_mappings.is_empty());
        assert!(!lowering.decomposition_patterns.is_empty());
    }

    #[test]
    fn test_primitive_check() {
        let lowering = OperationLowering::new();
        assert!(lowering.is_primitive(&OperationType::Add));
        assert!(lowering.is_primitive(&OperationType::Multiply));
    }

    #[test]
    fn test_hardware_capabilities() {
        let caps = HardwareCapabilities::default();
        assert!(!caps.supported_dtypes.is_empty());
        assert!(!caps.native_operations.is_empty());
    }
}