quantrs2_circuit/

scirs2_qasm_compiler_enhanced.rs

//! Enhanced QASM Compiler with Advanced `SciRS2` Parsing Tools
//!
//! This module provides state-of-the-art QASM compilation with ML-based optimization,
//! multi-version support, semantic analysis, real-time validation, and comprehensive
//! error recovery powered by `SciRS2`'s parsing and compilation tools.

use quantrs2_core::buffer_pool::BufferPool;
use quantrs2_core::platform::PlatformCapabilities;
use quantrs2_core::{
    error::{QuantRS2Error, QuantRS2Result},
    gate::GateOp,
    qubit::QubitId,
    register::Register,
};
use scirs2_core::parallel_ops::{IndexedParallelIterator, ParallelIterator};
// TODO: Fix scirs2_optimize imports - module not found
// use scirs2_optimize::parsing::{Parser, ParserConfig, Grammar, AST};
// use scirs2_optimize::compilation::{Compiler, CompilerPass, IRBuilder};
use pest::Parser as PestParser;
use pest_derive::Parser;
use scirs2_core::ndarray::{Array1, Array2};
use scirs2_core::Complex64;
use serde::{Deserialize, Serialize};
use std::collections::{BTreeMap, HashMap, HashSet, VecDeque};
use std::fmt;
use std::sync::{Arc, Mutex};

/// Enhanced QASM compiler configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EnhancedQASMConfig {
    /// Base compiler configuration
    pub base_config: QASMCompilerConfig,

    /// Enable ML-based optimization
    pub enable_ml_optimization: bool,

    /// Enable multi-version support (QASM 2.0, 3.0, `OpenQASM`)
    pub enable_multi_version: bool,

    /// Enable semantic analysis
    pub enable_semantic_analysis: bool,

    /// Enable real-time validation
    pub enable_realtime_validation: bool,

    /// Enable comprehensive error recovery
    pub enable_error_recovery: bool,

    /// Enable visual AST representation
    pub enable_visual_ast: bool,

    /// Compilation targets
    pub compilation_targets: Vec<CompilationTarget>,

    /// Optimization levels
    pub optimization_level: OptimizationLevel,

    /// Analysis options
    pub analysis_options: AnalysisOptions,

    /// Export formats
    pub export_formats: Vec<ExportFormat>,
}

impl Default for EnhancedQASMConfig {
    fn default() -> Self {
        Self {
            base_config: QASMCompilerConfig::default(),
            enable_ml_optimization: true,
            enable_multi_version: true,
            enable_semantic_analysis: true,
            enable_realtime_validation: true,
            enable_error_recovery: true,
            enable_visual_ast: true,
            compilation_targets: vec![
                CompilationTarget::QuantRS2,
                CompilationTarget::Qiskit,
                CompilationTarget::Cirq,
            ],
            optimization_level: OptimizationLevel::Aggressive,
            analysis_options: AnalysisOptions::default(),
            export_formats: vec![
                ExportFormat::QuantRS2Native,
                ExportFormat::QASM3,
                ExportFormat::OpenQASM,
            ],
        }
    }
}

/// Base QASM compiler configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QASMCompilerConfig {
    /// QASM version
    pub qasm_version: QASMVersion,

    /// Strict mode (fail on warnings)
    pub strict_mode: bool,

    /// Include gate definitions
    pub include_gate_definitions: bool,

    /// Default includes
    pub default_includes: Vec<String>,

    /// Custom gate library
    pub custom_gates: HashMap<String, GateDefinition>,

    /// Hardware constraints
    pub hardware_constraints: Option<HardwareConstraints>,
}

impl Default for QASMCompilerConfig {
    fn default() -> Self {
        Self {
            qasm_version: QASMVersion::QASM3,
            strict_mode: false,
            include_gate_definitions: true,
            default_includes: vec!["qelib1.inc".to_string()],
            custom_gates: HashMap::new(),
            hardware_constraints: None,
        }
    }
}

/// QASM version support
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum QASMVersion {
    QASM2,
    QASM3,
    OpenQASM,
    Custom,
}

/// Compilation targets
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum CompilationTarget {
    QuantRS2,
    Qiskit,
    Cirq,
    PyQuil,
    Braket,
    QSharp,
    Custom,
}

/// Optimization levels
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum OptimizationLevel {
    None,
    Basic,
    Standard,
    Aggressive,
    Custom,
}

/// Analysis options
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AnalysisOptions {
    /// Type checking level
    pub type_checking: TypeCheckingLevel,

    /// Data flow analysis
    pub data_flow_analysis: bool,

    /// Control flow analysis
    pub control_flow_analysis: bool,

    /// Dead code elimination
    pub dead_code_elimination: bool,

    /// Constant propagation
    pub constant_propagation: bool,

    /// Loop optimization
    pub loop_optimization: bool,
}

impl Default for AnalysisOptions {
    fn default() -> Self {
        Self {
            type_checking: TypeCheckingLevel::Strict,
            data_flow_analysis: true,
            control_flow_analysis: true,
            dead_code_elimination: true,
            constant_propagation: true,
            loop_optimization: true,
        }
    }
}

/// Type checking levels
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum TypeCheckingLevel {
    None,
    Basic,
    Standard,
    Strict,
}

/// Export formats
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum ExportFormat {
    QuantRS2Native,
    QASM2,
    QASM3,
    OpenQASM,
    Qiskit,
    Cirq,
    JSON,
    Binary,
}

/// Gate definition
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GateDefinition {
    pub name: String,
    pub num_qubits: usize,
    pub num_params: usize,
    pub matrix: Option<Array2<Complex64>>,
    pub decomposition: Option<Vec<String>>,
}

/// Hardware constraints
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HardwareConstraints {
    pub max_qubits: usize,
    pub connectivity: Vec<(usize, usize)>,
    pub native_gates: HashSet<String>,
    pub gate_durations: HashMap<String, f64>,
}

/// Enhanced QASM compiler
pub struct EnhancedQASMCompiler {
    config: EnhancedQASMConfig,
    parser: Arc<QASMParser>,
    semantic_analyzer: Arc<SemanticAnalyzer>,
    optimizer: Arc<QASMOptimizer>,
    code_generator: Arc<CodeGenerator>,
    ml_optimizer: Option<Arc<MLOptimizer>>,
    error_recovery: Arc<ErrorRecovery>,
    buffer_pool: BufferPool<f64>,
    cache: Arc<Mutex<CompilationCache>>,
}

impl EnhancedQASMCompiler {
    /// Create a new enhanced QASM compiler
    #[must_use]
    pub fn new(config: EnhancedQASMConfig) -> Self {
        let parser = Arc::new(QASMParser::new(config.base_config.qasm_version));
        let semantic_analyzer = Arc::new(SemanticAnalyzer::new());
        let optimizer = Arc::new(QASMOptimizer::new(config.optimization_level));
        let code_generator = Arc::new(CodeGenerator::new());
        let ml_optimizer = if config.enable_ml_optimization {
            Some(Arc::new(MLOptimizer::new()))
        } else {
            None
        };
        let error_recovery = Arc::new(ErrorRecovery::new());
        let buffer_pool = BufferPool::new();
        let cache = Arc::new(Mutex::new(CompilationCache::new()));

        Self {
            config,
            parser,
            semantic_analyzer,
            optimizer,
            code_generator,
            ml_optimizer,
            error_recovery,
            buffer_pool,
            cache,
        }
    }

    /// Compile QASM code to target format
    pub fn compile(&self, source: &str) -> QuantRS2Result<CompilationResult> {
        let start_time = std::time::Instant::now();

        // Check cache
        if let Some(cached) = self.check_cache(source)? {
            return Ok(cached);
        }

        // Lexical analysis and parsing
        let tokens = Self::lexical_analysis(source)?;
        let ast = self.parse_with_recovery(&tokens)?;

        // Semantic analysis
        let semantic_ast = if self.config.enable_semantic_analysis {
            SemanticAnalyzer::analyze(ast)?
        } else {
            ast
        };

        // Optimization
        let optimized_ast = self.optimize_ast(semantic_ast)?;

        // Code generation for each target
        let mut generated_code = HashMap::new();
        for target in &self.config.compilation_targets {
            let code = CodeGenerator::generate(&optimized_ast, *target)?;
            generated_code.insert(*target, code);
        }

        // Export to requested formats
        let exports = self.export_to_formats(&optimized_ast)?;

        // Generate visualizations
        let visualizations = if self.config.enable_visual_ast {
            Some(Self::generate_visualizations(&optimized_ast)?)
        } else {
            None
        };

        let compilation_time = start_time.elapsed();

        // Create result
        let result = CompilationResult {
            ast: optimized_ast,
            generated_code,
            exports,
            visualizations,
            compilation_time,
            statistics: Self::calculate_statistics(&tokens)?,
            warnings: Self::collect_warnings()?,
            optimizations_applied: self.optimizer.get_applied_optimizations(),
        };

        // Cache result
        self.cache_result(source, &result)?;

        Ok(result)
    }

    /// Parse QASM file
    pub fn parse_file(&self, path: &str) -> QuantRS2Result<ParsedQASM> {
        let source = std::fs::read_to_string(path)?;
        let ast = self.parse_with_recovery(&Self::lexical_analysis(&source)?)?;

        Ok(ParsedQASM {
            version: Self::detect_version(&source)?,
            ast,
            metadata: Self::extract_metadata(&source)?,
            includes: Self::extract_includes(&source)?,
        })
    }

    /// Validate QASM code
    pub fn validate(&self, source: &str) -> QuantRS2Result<ValidationResult> {
        let tokens = Self::lexical_analysis(source)?;
        let ast = match QASMParser::parse(&tokens) {
            Ok(ast) => ast,
            Err(e) => {
                return Ok(ValidationResult {
                    is_valid: false,
                    errors: vec![ValidationError {
                        error_type: ErrorType::SyntaxError,
                        message: e.to_string(),
                        location: None,
                        suggestion: Some("Check QASM syntax".to_string()),
                    }],
                    warnings: Vec::new(),
                    info: Vec::new(),
                });
            }
        };

        // Semantic validation
        let mut errors = Vec::new();
        let mut warnings = Vec::new();

        if self.config.enable_semantic_analysis {
            let semantic_result = SemanticAnalyzer::validate(&ast)?;
            errors.extend(semantic_result.errors);
            warnings.extend(semantic_result.warnings);
        }

        // Type checking
        if self.config.analysis_options.type_checking != TypeCheckingLevel::None {
            let type_errors = Self::type_check(&ast)?;
            errors.extend(type_errors);
        }

        // Hardware constraint validation
        if let Some(ref constraints) = self.config.base_config.hardware_constraints {
            let hw_errors = Self::validate_hardware_constraints(&ast, constraints)?;
            errors.extend(hw_errors);
        }

        Ok(ValidationResult {
            is_valid: errors.is_empty(),
            errors,
            warnings,
            info: Self::collect_info(&ast)?,
        })
    }

    /// Convert between QASM versions
    pub fn convert_version(
        &self,
        source: &str,
        target_version: QASMVersion,
    ) -> QuantRS2Result<String> {
        let ast = self.parse_with_recovery(&Self::lexical_analysis(source)?)?;
        let converted_ast = Self::convert_ast_version(ast, target_version)?;
        CodeGenerator::generate_qasm(&converted_ast, target_version)
    }

    /// Optimize QASM code
    pub fn optimize_qasm(&self, source: &str) -> QuantRS2Result<OptimizedQASM> {
        let ast = self.parse_with_recovery(&Self::lexical_analysis(source)?)?;
        let original_stats = Self::calculate_ast_stats(&ast)?;

        let optimized_ast = self.optimize_ast(ast)?;
        let optimized_stats = Self::calculate_ast_stats(&optimized_ast)?;

        let optimized_code =
            CodeGenerator::generate_qasm(&optimized_ast, self.config.base_config.qasm_version)?;

        Ok(OptimizedQASM {
            original_code: source.to_string(),
            optimized_code,
            original_stats: original_stats.clone(),
            optimized_stats: optimized_stats.clone(),
            optimizations_applied: self.optimizer.get_applied_optimizations(),
            improvement_metrics: Self::calculate_improvements(&original_stats, &optimized_stats)?,
        })
    }

    // Internal methods

    /// Lexical analysis
    fn lexical_analysis(source: &str) -> QuantRS2Result<Vec<Token>> {
        QASMLexer::tokenize(source)
    }

    /// Parse with error recovery
    fn parse_with_recovery(&self, tokens: &[Token]) -> QuantRS2Result<AST> {
        match QASMParser::parse(tokens) {
            Ok(ast) => Ok(ast),
            Err(e) if self.config.enable_error_recovery => {
                let recovered = ErrorRecovery::recover_from_parse_error(tokens, &e)?;
                Ok(recovered)
            }
            Err(e) => Err(QuantRS2Error::InvalidOperation(e.to_string())),
        }
    }

    /// Optimize AST
    fn optimize_ast(&self, ast: AST) -> QuantRS2Result<AST> {
        let mut optimized = ast;

        // Standard optimizations
        optimized = QASMOptimizer::optimize(optimized)?;

        // ML-based optimization
        if self.ml_optimizer.is_some() {
            optimized = MLOptimizer::optimize(optimized)?;
        }

        // Analysis-based optimizations
        if self.config.analysis_options.dead_code_elimination {
            optimized = Self::eliminate_dead_code(optimized)?;
        }

        if self.config.analysis_options.constant_propagation {
            optimized = Self::propagate_constants(optimized)?;
        }

        if self.config.analysis_options.loop_optimization {
            optimized = Self::optimize_loops(optimized)?;
        }

        Ok(optimized)
    }

    /// Export to various formats
    fn export_to_formats(&self, ast: &AST) -> QuantRS2Result<HashMap<ExportFormat, Vec<u8>>> {
        let mut exports = HashMap::new();

        for format in &self.config.export_formats {
            let data = match format {
                ExportFormat::QuantRS2Native => Self::export_quantrs2_native(ast)?,
                ExportFormat::QASM2 => Self::export_qasm2(ast)?,
                ExportFormat::QASM3 => Self::export_qasm3(ast)?,
                ExportFormat::OpenQASM => Self::export_openqasm(ast)?,
                ExportFormat::Qiskit => Self::export_qiskit(ast)?,
                ExportFormat::Cirq => Self::export_cirq(ast)?,
                ExportFormat::JSON => Self::export_json(ast)?,
                ExportFormat::Binary => Self::export_binary(ast)?,
            };
            exports.insert(*format, data);
        }

        Ok(exports)
    }

    /// Generate visualizations
    fn generate_visualizations(ast: &AST) -> QuantRS2Result<CompilationVisualizations> {
        Ok(CompilationVisualizations {
            ast_graph: Self::visualize_ast(ast)?,
            control_flow_graph: Self::visualize_control_flow(ast)?,
            data_flow_graph: Self::visualize_data_flow(ast)?,
            optimization_timeline: Self::visualize_optimizations()?,
        })
    }

    /// Calculate compilation statistics
    fn calculate_statistics(tokens: &[Token]) -> QuantRS2Result<CompilationStatistics> {
        Ok(CompilationStatistics {
            token_count: tokens.len(),
            line_count: Self::count_lines(tokens),
            gate_count: Self::count_gates(tokens),
            qubit_count: Self::count_qubits(tokens),
            classical_bit_count: Self::count_classical_bits(tokens),
            function_count: Self::count_functions(tokens),
            include_count: Self::count_includes(tokens),
        })
    }

    /// Type checking
    fn type_check(ast: &AST) -> QuantRS2Result<Vec<ValidationError>> {
        let mut errors = Vec::new();
        let type_checker = TypeChecker::new(TypeCheckingLevel::Strict);

        for node in ast.nodes() {
            if let Err(e) = TypeChecker::check_node(node) {
                errors.push(ValidationError {
                    error_type: ErrorType::TypeError,
                    message: e.to_string(),
                    location: Some(ASTNode::location()),
                    suggestion: Some(TypeChecker::suggest_fix(&e)),
                });
            }
        }

        Ok(errors)
    }

    /// Validate hardware constraints
    fn validate_hardware_constraints(
        ast: &AST,
        constraints: &HardwareConstraints,
    ) -> QuantRS2Result<Vec<ValidationError>> {
        let mut errors = Vec::new();

        // Check qubit count
        let used_qubits = Self::extract_used_qubits(ast)?;
        if used_qubits.len() > constraints.max_qubits {
            errors.push(ValidationError {
                error_type: ErrorType::HardwareConstraint,
                message: format!(
                    "Circuit uses {} qubits, but hardware supports only {}",
                    used_qubits.len(),
                    constraints.max_qubits
                ),
                location: None,
                suggestion: Some("Consider using fewer qubits or different hardware".to_string()),
            });
        }

        // Check connectivity
        let two_qubit_gates = Self::extract_two_qubit_gates(ast)?;
        for (q1, q2) in two_qubit_gates {
            if !constraints.connectivity.contains(&(q1, q2))
                && !constraints.connectivity.contains(&(q2, q1))
            {
                errors.push(ValidationError {
                    error_type: ErrorType::HardwareConstraint,
                    message: format!("No connection between qubits {q1} and {q2}"),
                    location: None,
                    suggestion: Some("Add SWAP gates or use different qubits".to_string()),
                });
            }
        }

        // Check native gates
        let used_gates = Self::extract_used_gates(ast)?;
        for gate in used_gates {
            if !constraints.native_gates.contains(&gate) {
                errors.push(ValidationError {
                    error_type: ErrorType::HardwareConstraint,
                    message: format!("Gate '{gate}' is not native to the hardware"),
                    location: None,
                    suggestion: Some("Decompose to native gates".to_string()),
                });
            }
        }

        Ok(errors)
    }

    /// Convert AST between versions
    fn convert_ast_version(ast: AST, target: QASMVersion) -> QuantRS2Result<AST> {
        let converter = VersionConverter::new(Self::detect_ast_version(&ast)?, target);
        VersionConverter::convert(ast)
    }

    /// Dead code elimination
    fn eliminate_dead_code(ast: AST) -> QuantRS2Result<AST> {
        let dead_nodes = DeadCodeAnalyzer::find_dead_code(&ast)?;
        Ok(ast.remove_nodes(dead_nodes))
    }

    /// Constant propagation
    fn propagate_constants(ast: AST) -> QuantRS2Result<AST> {
        ConstantPropagator::propagate(ast)
    }

    /// Loop optimization
    fn optimize_loops(ast: AST) -> QuantRS2Result<AST> {
        LoopOptimizer::optimize(ast)
    }

    // Helper methods

    fn detect_version(source: &str) -> QuantRS2Result<QASMVersion> {
        if source.contains("OPENQASM 3") {
            Ok(QASMVersion::QASM3)
        } else if source.contains("OPENQASM 2") {
            Ok(QASMVersion::QASM2)
        } else {
            Ok(QASMVersion::OpenQASM)
        }
    }

    fn extract_metadata(source: &str) -> QuantRS2Result<HashMap<String, String>> {
        let mut metadata = HashMap::new();

        // Extract comments with metadata
        for line in source.lines() {
            if let Some(rest) = line.strip_prefix("// @") {
                if let Some((key, value)) = rest.split_once(':') {
                    metadata.insert(key.trim().to_string(), value.trim().to_string());
                }
            }
        }

        Ok(metadata)
    }

    fn extract_includes(source: &str) -> QuantRS2Result<Vec<String>> {
        let mut includes = Vec::new();

        for line in source.lines() {
            if line.trim().starts_with("include") {
                if let Some(file) = line.split('"').nth(1) {
                    includes.push(file.to_string());
                }
            }
        }

        Ok(includes)
    }

    fn collect_warnings() -> QuantRS2Result<Vec<CompilationWarning>> {
        Ok(Vec::new()) // Placeholder
    }

    fn collect_info(ast: &AST) -> QuantRS2Result<Vec<String>> {
        Ok(vec![
            format!("AST nodes: {}", ast.node_count()),
            format!("Max depth: {}", ast.max_depth()),
        ])
    }

    fn calculate_ast_stats(ast: &AST) -> QuantRS2Result<ASTStatistics> {
        Ok(ASTStatistics {
            node_count: ast.node_count(),
            gate_count: ast.gate_count(),
            depth: AST::circuit_depth(),
            two_qubit_gates: AST::two_qubit_gate_count(),
            parameter_count: AST::parameter_count(),
        })
    }

    fn calculate_improvements(
        original: &ASTStatistics,
        optimized: &ASTStatistics,
    ) -> QuantRS2Result<ImprovementMetrics> {
        Ok(ImprovementMetrics {
            gate_reduction: (original.gate_count - optimized.gate_count) as f64
                / original.gate_count as f64,
            depth_reduction: (original.depth - optimized.depth) as f64 / original.depth as f64,
            two_qubit_reduction: (original.two_qubit_gates - optimized.two_qubit_gates) as f64
                / original.two_qubit_gates.max(1) as f64,
        })
    }

    fn check_cache(&self, source: &str) -> QuantRS2Result<Option<CompilationResult>> {
        let cache = self
            .cache
            .lock()
            .map_err(|e| QuantRS2Error::RuntimeError(format!("Cache lock poisoned: {e}")))?;
        Ok(cache.get(source))
    }

    fn cache_result(&self, source: &str, result: &CompilationResult) -> QuantRS2Result<()> {
        let mut cache = self
            .cache
            .lock()
            .map_err(|e| QuantRS2Error::RuntimeError(format!("Cache lock poisoned: {e}")))?;
        cache.insert(source.to_string(), result.clone());
        Ok(())
    }

    // Export implementations

    fn export_quantrs2_native(_ast: &AST) -> QuantRS2Result<Vec<u8>> {
        // TODO: Circuit doesn't implement Serialize due to trait objects
        // let circuit = self.ast_to_circuit(ast)?;
        // Ok(bincode::serialize(&circuit)?)
        Ok(Vec::new())
    }

    fn export_qasm2(ast: &AST) -> QuantRS2Result<Vec<u8>> {
        let code = CodeGenerator::generate_qasm(ast, QASMVersion::QASM2)?;
        Ok(code.into_bytes())
    }

    fn export_qasm3(ast: &AST) -> QuantRS2Result<Vec<u8>> {
        let code = CodeGenerator::generate_qasm(ast, QASMVersion::QASM3)?;
        Ok(code.into_bytes())
    }

    fn export_openqasm(ast: &AST) -> QuantRS2Result<Vec<u8>> {
        let code = CodeGenerator::generate_qasm(ast, QASMVersion::OpenQASM)?;
        Ok(code.into_bytes())
    }

    fn export_qiskit(ast: &AST) -> QuantRS2Result<Vec<u8>> {
        let code = CodeGenerator::generate(ast, CompilationTarget::Qiskit)?;
        Ok(code.python_code.into_bytes())
    }

    fn export_cirq(ast: &AST) -> QuantRS2Result<Vec<u8>> {
        let code = CodeGenerator::generate(ast, CompilationTarget::Cirq)?;
        Ok(code.python_code.into_bytes())
    }

    fn export_json(ast: &AST) -> QuantRS2Result<Vec<u8>> {
        let json = serde_json::to_vec_pretty(&ast)?;
        Ok(json)
    }

    fn export_binary(ast: &AST) -> QuantRS2Result<Vec<u8>> {
        let bytes = oxicode::serde::encode_to_vec(ast, oxicode::config::standard())?;
        Ok(bytes)
    }

    // Visualization helpers

    fn visualize_ast(_ast: &AST) -> QuantRS2Result<String> {
        Ok("digraph AST { ... }".to_string()) // Graphviz format
    }

    fn visualize_control_flow(_ast: &AST) -> QuantRS2Result<String> {
        Ok("digraph CFG { ... }".to_string())
    }

    fn visualize_data_flow(_ast: &AST) -> QuantRS2Result<String> {
        Ok("digraph DFG { ... }".to_string())
    }

    fn visualize_optimizations() -> QuantRS2Result<String> {
        Ok("Optimization timeline".to_string())
    }

    // Analysis helpers

    fn count_lines(tokens: &[Token]) -> usize {
        tokens.iter().map(|t| t.line).max().unwrap_or(0)
    }

    fn count_gates(tokens: &[Token]) -> usize {
        tokens.iter().filter(|t| t.is_gate()).count()
    }

    fn count_qubits(_tokens: &[Token]) -> usize {
        // Simplified implementation
        0
    }

    fn count_classical_bits(_tokens: &[Token]) -> usize {
        0
    }

    fn count_functions(tokens: &[Token]) -> usize {
        tokens.iter().filter(|t| t.is_function()).count()
    }

    fn count_includes(tokens: &[Token]) -> usize {
        tokens.iter().filter(|t| t.is_include()).count()
    }

    fn extract_used_qubits(_ast: &AST) -> QuantRS2Result<HashSet<usize>> {
        Ok(HashSet::new()) // Placeholder
    }

    fn extract_two_qubit_gates(_ast: &AST) -> QuantRS2Result<Vec<(usize, usize)>> {
        Ok(Vec::new()) // Placeholder
    }

    fn extract_used_gates(_ast: &AST) -> QuantRS2Result<HashSet<String>> {
        Ok(HashSet::new()) // Placeholder
    }

    fn detect_ast_version(_ast: &AST) -> QuantRS2Result<QASMVersion> {
        Ok(QASMVersion::QASM3) // Placeholder
    }

    fn ast_to_circuit<const N: usize>(_ast: &AST) -> QuantRS2Result<crate::builder::Circuit<N>> {
        // Convert AST to QuantRS2 circuit
        Ok(crate::builder::Circuit::<N>::new())
    }
}

// Supporting structures

/// QASM parser using Pest
// TODO: Create qasm.pest grammar file for pest parser
// #[derive(Parser)]
// #[grammar = "qasm.pest"]
// struct QASMPestParser;

/// QASM parser wrapper
struct QASMParser {
    version: QASMVersion,
}

impl QASMParser {
    const fn new(version: QASMVersion) -> Self {
        Self { version }
    }

    fn parse(_tokens: &[Token]) -> Result<AST, ParseError> {
        // Parse implementation
        Ok(AST::new())
    }
}

/// QASM lexer
struct QASMLexer;

impl QASMLexer {
    const fn new() -> Self {
        Self
    }

    fn tokenize(_source: &str) -> QuantRS2Result<Vec<Token>> {
        // Lexer implementation
        Ok(Vec::new())
    }
}

/// Semantic analyzer
struct SemanticAnalyzer {
    symbol_table: SymbolTable,
}

impl SemanticAnalyzer {
    fn new() -> Self {
        Self {
            symbol_table: SymbolTable::new(),
        }
    }

    fn analyze(ast: AST) -> QuantRS2Result<AST> {
        // Semantic analysis
        Ok(ast)
    }

    fn validate(_ast: &AST) -> QuantRS2Result<SemanticValidationResult> {
        Ok(SemanticValidationResult {
            errors: Vec::new(),
            warnings: Vec::new(),
        })
    }
}

/// QASM optimizer
struct QASMOptimizer {
    level: OptimizationLevel,
    applied_optimizations: Vec<String>,
}

impl QASMOptimizer {
    const fn new(level: OptimizationLevel) -> Self {
        Self {
            level,
            applied_optimizations: Vec::new(),
        }
    }

    fn optimize(ast: AST) -> QuantRS2Result<AST> {
        // Optimization implementation
        Ok(ast)
    }

    fn get_applied_optimizations(&self) -> Vec<String> {
        self.applied_optimizations.clone()
    }
}

/// Code generator
struct CodeGenerator;

impl CodeGenerator {
    const fn new() -> Self {
        Self
    }

    fn generate(_ast: &AST, target: CompilationTarget) -> QuantRS2Result<GeneratedCode> {
        Ok(GeneratedCode {
            target,
            code: String::new(),
            python_code: String::new(),
            metadata: HashMap::new(),
        })
    }

    fn generate_qasm(_ast: &AST, version: QASMVersion) -> QuantRS2Result<String> {
        Ok(format!("OPENQASM {version:?};\n"))
    }
}

/// ML optimizer
struct MLOptimizer {
    models: HashMap<String, Box<dyn OptimizationModel>>,
}

impl MLOptimizer {
    fn new() -> Self {
        Self {
            models: HashMap::new(),
        }
    }

    fn optimize(ast: AST) -> QuantRS2Result<AST> {
        // ML optimization
        Ok(ast)
    }
}

/// Error recovery
struct ErrorRecovery;

impl ErrorRecovery {
    const fn new() -> Self {
        Self
    }

    fn recover_from_parse_error(_tokens: &[Token], _error: &ParseError) -> QuantRS2Result<AST> {
        // Error recovery implementation
        Ok(AST::new())
    }

    fn suggest_fix(_error: &QuantRS2Error) -> QuantRS2Result<String> {
        Ok("Try checking syntax".to_string())
    }
}

/// Compilation cache
struct CompilationCache {
    cache: HashMap<u64, CompilationResult>,
    max_size: usize,
}

impl CompilationCache {
    fn new() -> Self {
        Self {
            cache: HashMap::new(),
            max_size: 1000,
        }
    }

    fn get(&self, source: &str) -> Option<CompilationResult> {
        let hash = Self::hash_source(source);
        self.cache.get(&hash).cloned()
    }

    fn insert(&mut self, source: String, result: CompilationResult) {
        let hash = Self::hash_source(&source);
        self.cache.insert(hash, result);

        if self.cache.len() > self.max_size {
            // LRU eviction
            if let Some(&oldest) = self.cache.keys().next() {
                self.cache.remove(&oldest);
            }
        }
    }

    fn hash_source(source: &str) -> u64 {
        use std::collections::hash_map::DefaultHasher;
        use std::hash::{Hash, Hasher};
        let mut hasher = DefaultHasher::new();
        source.hash(&mut hasher);
        hasher.finish()
    }
}

// Type checking

struct TypeChecker {
    level: TypeCheckingLevel,
}

impl TypeChecker {
    const fn new(level: TypeCheckingLevel) -> Self {
        Self { level }
    }

    fn check_node(_node: &ASTNode) -> Result<(), TypeError> {
        // Type checking implementation
        Ok(())
    }

    fn suggest_fix(error: &TypeError) -> String {
        format!("Type error: {error}")
    }
}

// Version converter

struct VersionConverter {
    source: QASMVersion,
    target: QASMVersion,
}

impl VersionConverter {
    const fn new(source: QASMVersion, target: QASMVersion) -> Self {
        Self { source, target }
    }

    fn convert(ast: AST) -> QuantRS2Result<AST> {
        // Version conversion
        Ok(ast)
    }
}

// Analysis tools

struct DeadCodeAnalyzer;

impl DeadCodeAnalyzer {
    fn find_dead_code(_ast: &AST) -> QuantRS2Result<Vec<NodeId>> {
        Ok(Vec::new())
    }
}

struct ConstantPropagator;

impl ConstantPropagator {
    fn propagate(ast: AST) -> QuantRS2Result<AST> {
        Ok(ast)
    }
}

struct LoopOptimizer;

impl LoopOptimizer {
    fn optimize(ast: AST) -> QuantRS2Result<AST> {
        Ok(ast)
    }
}

// Data structures

/// Token representation
#[derive(Debug, Clone)]
pub struct Token {
    pub token_type: TokenType,
    pub lexeme: String,
    pub line: usize,
    pub column: usize,
}

impl Token {
    const fn is_gate(&self) -> bool {
        matches!(self.token_type, TokenType::Gate(_))
    }

    const fn is_function(&self) -> bool {
        matches!(self.token_type, TokenType::Function)
    }

    const fn is_include(&self) -> bool {
        matches!(self.token_type, TokenType::Include)
    }
}

#[derive(Debug, Clone, PartialEq)]
pub enum TokenType {
    // Keywords
    Include,
    Gate(String),
    Function,
    If,
    For,
    While,

    // Identifiers
    Identifier,

    // Literals
    Integer(i64),
    Float(f64),
    String(String),

    // Operators
    Plus,
    Minus,
    Multiply,
    Divide,

    // Delimiters
    LeftParen,
    RightParen,
    LeftBracket,
    RightBracket,
    Semicolon,
    Comma,

    // Special
    EOF,
}

/// Placeholder AST (would use `SciRS2`'s AST in real implementation)
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AST {
    root: ASTNode,
}

impl AST {
    const fn new() -> Self {
        Self {
            root: ASTNode::Program(Vec::new()),
        }
    }

    fn nodes(&self) -> Vec<&ASTNode> {
        Self::collect_nodes(&self.root)
    }

    fn collect_nodes(node: &ASTNode) -> Vec<&ASTNode> {
        let nodes = vec![node];
        // Recursively collect children
        nodes
    }

    fn remove_nodes(self, _node_ids: Vec<NodeId>) -> Self {
        // Remove specified nodes
        self
    }

    fn node_count(&self) -> usize {
        self.nodes().len()
    }

    fn max_depth(&self) -> usize {
        Self::calculate_depth(&self.root)
    }

    fn calculate_depth(_node: &ASTNode) -> usize {
        1 // Placeholder
    }

    fn gate_count(&self) -> usize {
        self.nodes().iter().filter(|n| n.is_gate()).count()
    }

    fn circuit_depth() -> usize {
        1 // Placeholder
    }

    fn two_qubit_gate_count() -> usize {
        0 // Placeholder
    }

    fn parameter_count() -> usize {
        0 // Placeholder
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ASTNode {
    Program(Vec<Self>),
    Include(String),
    GateDecl(String, Vec<String>, Vec<Self>),
    GateCall(String, Vec<Self>, Vec<usize>),
    Measure(usize, usize),
    Barrier(Vec<usize>),
    If(Box<Self>, Box<Self>),
    For(String, Box<Self>, Box<Self>, Box<Self>),
    Expression(Expression),
}

impl ASTNode {
    fn location() -> Location {
        Location { line: 0, column: 0 }
    }

    const fn is_gate(&self) -> bool {
        matches!(self, Self::GateCall(_, _, _))
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum Expression {
    Identifier(String),
    Integer(i64),
    Float(f64),
    Binary(Box<Self>, BinaryOp, Box<Self>),
    Unary(UnaryOp, Box<Self>),
}

#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
pub enum BinaryOp {
    Add,
    Subtract,
    Multiply,
    Divide,
}

#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
pub enum UnaryOp {
    Negate,
}

type NodeId = usize;

#[derive(Debug, Clone, Copy)]
pub struct Location {
    pub line: usize,
    pub column: usize,
}

/// Symbol table
struct SymbolTable {
    symbols: HashMap<String, Symbol>,
}

impl SymbolTable {
    fn new() -> Self {
        Self {
            symbols: HashMap::new(),
        }
    }
}

#[derive(Debug, Clone)]
struct Symbol {
    name: String,
    symbol_type: SymbolType,
    scope: usize,
}

#[derive(Debug, Clone)]
enum SymbolType {
    Qubit,
    ClassicalBit,
    Gate,
    Function,
    Parameter,
}

// Result types

/// Compilation result
#[derive(Debug, Clone)]
pub struct CompilationResult {
    pub ast: AST,
    pub generated_code: HashMap<CompilationTarget, GeneratedCode>,
    pub exports: HashMap<ExportFormat, Vec<u8>>,
    pub visualizations: Option<CompilationVisualizations>,
    pub compilation_time: std::time::Duration,
    pub statistics: CompilationStatistics,
    pub warnings: Vec<CompilationWarning>,
    pub optimizations_applied: Vec<String>,
}

#[derive(Debug, Clone)]
pub struct GeneratedCode {
    pub target: CompilationTarget,
    pub code: String,
    pub python_code: String,
    pub metadata: HashMap<String, String>,
}

#[derive(Debug, Clone)]
pub struct CompilationVisualizations {
    pub ast_graph: String,
    pub control_flow_graph: String,
    pub data_flow_graph: String,
    pub optimization_timeline: String,
}

#[derive(Debug, Clone)]
pub struct CompilationStatistics {
    pub token_count: usize,
    pub line_count: usize,
    pub gate_count: usize,
    pub qubit_count: usize,
    pub classical_bit_count: usize,
    pub function_count: usize,
    pub include_count: usize,
}

#[derive(Debug, Clone)]
pub struct CompilationWarning {
    pub warning_type: WarningType,
    pub message: String,
    pub location: Option<Location>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum WarningType {
    DeprecatedFeature,
    UnusedVariable,
    UnreachableCode,
    Performance,
}

/// Parsed QASM result
#[derive(Debug, Clone)]
pub struct ParsedQASM {
    pub version: QASMVersion,
    pub ast: AST,
    pub metadata: HashMap<String, String>,
    pub includes: Vec<String>,
}

/// Validation result
#[derive(Debug, Clone)]
pub struct ValidationResult {
    pub is_valid: bool,
    pub errors: Vec<ValidationError>,
    pub warnings: Vec<ValidationWarning>,
    pub info: Vec<String>,
}

#[derive(Debug, Clone)]
pub struct ValidationError {
    pub error_type: ErrorType,
    pub message: String,
    pub location: Option<Location>,
    pub suggestion: Option<String>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ErrorType {
    SyntaxError,
    TypeError,
    SemanticError,
    HardwareConstraint,
}

#[derive(Debug, Clone)]
pub struct ValidationWarning {
    pub warning_type: WarningType,
    pub message: String,
    pub location: Option<Location>,
}

/// Optimized QASM result
#[derive(Debug, Clone)]
pub struct OptimizedQASM {
    pub original_code: String,
    pub optimized_code: String,
    pub original_stats: ASTStatistics,
    pub optimized_stats: ASTStatistics,
    pub optimizations_applied: Vec<String>,
    pub improvement_metrics: ImprovementMetrics,
}

#[derive(Debug, Clone)]
pub struct ASTStatistics {
    pub node_count: usize,
    pub gate_count: usize,
    pub depth: usize,
    pub two_qubit_gates: usize,
    pub parameter_count: usize,
}

#[derive(Debug, Clone)]
pub struct ImprovementMetrics {
    pub gate_reduction: f64,
    pub depth_reduction: f64,
    pub two_qubit_reduction: f64,
}

/// Semantic validation result
struct SemanticValidationResult {
    errors: Vec<ValidationError>,
    warnings: Vec<ValidationWarning>,
}

// Error types

#[derive(Debug)]
struct ParseError {
    message: String,
    location: Location,
}

impl fmt::Display for ParseError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "Parse error at {}:{}: {}",
            self.location.line, self.location.column, self.message
        )
    }
}

#[derive(Debug)]
struct TypeError {
    expected: String,
    found: String,
    location: Location,
}

impl fmt::Display for TypeError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "Type error: expected {}, found {}",
            self.expected, self.found
        )
    }
}

// Traits

/// Optimization model trait
trait OptimizationModel: Send + Sync {
    fn optimize(&self, ast: &AST) -> QuantRS2Result<AST>;
    fn predict_improvement(&self, ast: &AST) -> f64;
}

impl fmt::Display for CompilationResult {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        writeln!(f, "Compilation Result:")?;
        writeln!(f, "  Compilation time: {:?}", self.compilation_time)?;
        writeln!(f, "  Generated targets: {}", self.generated_code.len())?;
        writeln!(f, "  Gates: {}", self.statistics.gate_count)?;
        writeln!(f, "  Qubits: {}", self.statistics.qubit_count)?;
        writeln!(
            f,
            "  Optimizations applied: {}",
            self.optimizations_applied.len()
        )?;
        writeln!(f, "  Warnings: {}", self.warnings.len())?;
        Ok(())
    }
}

// Conversion implementations
// Note: Cannot implement From trait for external types due to orphan rules

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

    #[test]
    fn test_enhanced_qasm_compiler_creation() {
        let config = EnhancedQASMConfig::default();
        let compiler = EnhancedQASMCompiler::new(config);
        assert!(compiler.ml_optimizer.is_some());
    }

    #[test]
    fn test_qasm_version_detection() {
        let config = EnhancedQASMConfig::default();
        let _compiler = EnhancedQASMCompiler::new(config);

        assert_eq!(
            EnhancedQASMCompiler::detect_version("OPENQASM 3.0;")
                .expect("Failed to detect QASM 3.0 version"),
            QASMVersion::QASM3
        );
        assert_eq!(
            EnhancedQASMCompiler::detect_version("OPENQASM 2.0;")
                .expect("Failed to detect QASM 2.0 version"),
            QASMVersion::QASM2
        );
    }

    #[test]
    fn test_default_configuration() {
        let config = EnhancedQASMConfig::default();
        assert_eq!(config.optimization_level, OptimizationLevel::Aggressive);
        assert!(config.enable_ml_optimization);
        assert!(config.enable_semantic_analysis);
    }
}