quantrs2_core/

scirs2_quantum_formatter.rs

//! SciRS2-Enhanced Quantum Code Formatter
//!
//! This module provides intelligent code formatting and restructuring for quantum circuits
//! using SciRS2's advanced code analysis, optimization-aware formatting, and style guidelines.

use crate::error::QuantRS2Error;
use crate::gate_translation::GateType;
use std::collections::HashSet;

use std::fmt::Write;
/// SciRS2-enhanced quantum gate representation for formatting
#[derive(Debug, Clone)]
pub struct QuantumGate {
    gate_type: GateType,
    target_qubits: Vec<usize>,
    control_qubits: Option<Vec<usize>>,
}

impl QuantumGate {
    pub const fn new(
        gate_type: GateType,
        target_qubits: Vec<usize>,
        control_qubits: Option<Vec<usize>>,
    ) -> Self {
        Self {
            gate_type,
            target_qubits,
            control_qubits,
        }
    }

    pub const fn gate_type(&self) -> &GateType {
        &self.gate_type
    }

    pub fn target_qubits(&self) -> &[usize] {
        &self.target_qubits
    }

    pub fn control_qubits(&self) -> Option<&[usize]> {
        self.control_qubits.as_deref()
    }
}

/// Configuration for SciRS2-enhanced quantum code formatting
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct FormattingConfig {
    /// Enable optimization-aware formatting
    pub optimization_aware_formatting: bool,
    /// Enable gate grouping by type
    pub group_gates_by_type: bool,
    /// Enable qubit-aware line organization
    pub organize_by_qubits: bool,
    /// Enable parallel gate alignment
    pub align_parallel_gates: bool,
    /// Enable compact representation for simple patterns
    pub enable_compact_patterns: bool,
    /// Enable SciRS2 optimization annotations
    pub add_scirs2_annotations: bool,
    /// Maximum line length for formatting
    pub max_line_length: usize,
    /// Indentation style
    pub indentation_style: IndentationStyle,
    /// Comment style for annotations
    pub comment_style: CommentStyle,
    /// Enable performance hints in formatting
    pub include_performance_hints: bool,
    /// Enable memory usage annotations
    pub annotate_memory_usage: bool,
    /// Enable SIMD optimization hints
    pub include_simd_hints: bool,
}

impl Default for FormattingConfig {
    fn default() -> Self {
        Self {
            optimization_aware_formatting: true,
            group_gates_by_type: true,
            organize_by_qubits: false,
            align_parallel_gates: true,
            enable_compact_patterns: true,
            add_scirs2_annotations: true,
            max_line_length: 120,
            indentation_style: IndentationStyle::Spaces(4),
            comment_style: CommentStyle::LineComment,
            include_performance_hints: true,
            annotate_memory_usage: true,
            include_simd_hints: true,
        }
    }
}

/// Indentation styles for formatted code
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub enum IndentationStyle {
    Spaces(usize),
    Tabs,
    Mixed(usize, usize), // (spaces_per_tab, tab_count)
}

/// Comment styles for annotations
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub enum CommentStyle {
    LineComment,  // //
    BlockComment, // /* */
    DocComment,   // ///
}

/// Output format options
#[derive(Debug, Clone, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
pub enum OutputFormat {
    Rust,
    Python,
    QASM,
    Text,
    Markdown,
    LaTeX,
    Html,
}

/// SciRS2-enhanced quantum code formatter
pub struct SciRS2QuantumFormatter {
    config: FormattingConfig,
    circuit_analyzer: CircuitAnalyzer,
    optimization_detector: OptimizationDetector,
    pattern_recognizer: PatternRecognizer,
    layout_optimizer: LayoutOptimizer,
    annotation_generator: AnnotationGenerator,
    style_engine: StyleEngine,
}

impl SciRS2QuantumFormatter {
    /// Create a new SciRS2-enhanced quantum formatter
    pub fn new() -> Self {
        let config = FormattingConfig::default();
        Self::with_config(config)
    }

    /// Create formatter with custom configuration
    pub const fn with_config(config: FormattingConfig) -> Self {
        Self {
            config,
            circuit_analyzer: CircuitAnalyzer::new(),
            optimization_detector: OptimizationDetector::new(),
            pattern_recognizer: PatternRecognizer::new(),
            layout_optimizer: LayoutOptimizer::new(),
            annotation_generator: AnnotationGenerator::new(),
            style_engine: StyleEngine::new(),
        }
    }

    /// Format a quantum circuit with SciRS2 enhancements
    pub fn format_circuit(
        &self,
        circuit: &[QuantumGate],
        num_qubits: usize,
        output_format: OutputFormat,
    ) -> Result<FormattedCode, QuantRS2Error> {
        // Analyze the circuit structure
        let analysis = self.circuit_analyzer.analyze_circuit(circuit, num_qubits)?;

        // Detect optimization opportunities
        let optimizations = if self.config.optimization_aware_formatting {
            self.optimization_detector
                .detect_optimizations(circuit, &analysis)?
        } else {
            Vec::new()
        };

        // Recognize common patterns
        let patterns = if self.config.enable_compact_patterns {
            self.pattern_recognizer.recognize_patterns(circuit)?
        } else {
            Vec::new()
        };

        // Optimize layout for readability and performance understanding
        let layout = self
            .layout_optimizer
            .optimize_layout(circuit, &analysis, &patterns)?;

        // Generate annotations
        let annotations = if self.config.add_scirs2_annotations {
            self.annotation_generator
                .generate_annotations(circuit, &analysis, &optimizations)?
        } else {
            Vec::new()
        };

        // Apply styling based on output format
        let formatted_code =
            self.style_engine
                .apply_styling(&layout, &annotations, &output_format, &self.config)?;

        Ok(FormattedCode {
            code: formatted_code.clone(),
            output_format,
            analysis,
            optimizations,
            patterns,
            annotations,
            formatting_statistics: self.calculate_formatting_statistics(circuit, &formatted_code),
        })
    }

    /// Format a gate sequence with specific styling
    pub fn format_gate_sequence(
        &self,
        gates: &[QuantumGate],
        style: FormattingStyle,
    ) -> Result<String, QuantRS2Error> {
        match style {
            FormattingStyle::Compact => self.format_compact_sequence(gates),
            FormattingStyle::Verbose => self.format_verbose_sequence(gates),
            FormattingStyle::OptimizationAware => self.format_optimization_aware_sequence(gates),
            FormattingStyle::SciRS2Enhanced => self.format_scirs2_enhanced_sequence(gates),
        }
    }

    /// Format in compact style
    fn format_compact_sequence(&self, gates: &[QuantumGate]) -> Result<String, QuantRS2Error> {
        let mut formatted = String::new();

        for (i, gate) in gates.iter().enumerate() {
            if i > 0 {
                formatted.push_str("; ");
            }
            formatted.push_str(&self.format_single_gate_compact(gate));
        }

        Ok(formatted)
    }

    /// Format single gate in compact style
    fn format_single_gate_compact(&self, gate: &QuantumGate) -> String {
        match gate.gate_type() {
            GateType::X => format!("X({})", gate.target_qubits()[0]),
            GateType::Y => format!("Y({})", gate.target_qubits()[0]),
            GateType::Z => format!("Z({})", gate.target_qubits()[0]),
            GateType::H => format!("H({})", gate.target_qubits()[0]),
            GateType::CNOT => format!(
                "CNOT({}, {})",
                gate.target_qubits()[0],
                gate.target_qubits()[1]
            ),
            GateType::T => format!("T({})", gate.target_qubits()[0]),
            GateType::S => format!("S({})", gate.target_qubits()[0]),
            GateType::Rx(angle) => format!("Rx({}, {})", angle, gate.target_qubits()[0]),
            GateType::Ry(angle) => format!("Ry({}, {})", angle, gate.target_qubits()[0]),
            GateType::Rz(angle) => format!("Rz({}, {})", angle, gate.target_qubits()[0]),
            GateType::Phase(angle) => format!("P({}, {})", angle, gate.target_qubits()[0]),
            _ => format!("{:?}({:?})", gate.gate_type(), gate.target_qubits()),
        }
    }

    /// Format in verbose style
    fn format_verbose_sequence(&self, gates: &[QuantumGate]) -> Result<String, QuantRS2Error> {
        let mut formatted = String::new();

        for (i, gate) in gates.iter().enumerate() {
            writeln!(
                formatted,
                "Step {}: {}",
                i + 1,
                self.format_single_gate_verbose(gate)
            )
            .expect("Writing to String cannot fail");
        }

        Ok(formatted)
    }

    /// Format single gate in verbose style
    fn format_single_gate_verbose(&self, gate: &QuantumGate) -> String {
        let gate_description = match gate.gate_type() {
            GateType::X => "Pauli-X (NOT) gate",
            GateType::Y => "Pauli-Y gate",
            GateType::Z => "Pauli-Z gate",
            GateType::H => "Hadamard gate",
            GateType::CNOT => "Controlled-NOT gate",
            GateType::T => "T gate (π/8 rotation)",
            GateType::S => "S gate (π/4 rotation)",
            GateType::Rx(_) => "X-axis rotation gate",
            GateType::Ry(_) => "Y-axis rotation gate",
            GateType::Rz(_) => "Z-axis rotation gate",
            GateType::Phase(_) => "Phase gate",
            _ => "Quantum gate",
        };

        let targets = gate
            .target_qubits()
            .iter()
            .map(|q| format!("q{q}"))
            .collect::<Vec<_>>()
            .join(", ");

        let controls = if let Some(ctrl_qubits) = gate.control_qubits() {
            let ctrl_str = ctrl_qubits
                .iter()
                .map(|q| format!("q{q}"))
                .collect::<Vec<_>>()
                .join(", ");
            format!(" controlled by [{ctrl_str}]")
        } else {
            String::new()
        };

        format!("{gate_description} on [{targets}]{controls}")
    }

    /// Format in optimization-aware style
    fn format_optimization_aware_sequence(
        &self,
        gates: &[QuantumGate],
    ) -> Result<String, QuantRS2Error> {
        let mut formatted = String::new();
        let optimizations = self
            .optimization_detector
            .detect_optimizations(gates, &CircuitAnalysis::default())?;

        formatted.push_str("// Optimization-aware formatting\n");
        if !optimizations.is_empty() {
            formatted.push_str("// Detected optimizations:\n");
            for opt in &optimizations {
                writeln!(formatted, "//   - {}", opt.description)
                    .expect("Writing to String cannot fail");
            }
            formatted.push('\n');
        }

        // Group gates by optimization potential
        let (optimizable, regular): (Vec<_>, Vec<_>) = gates
            .iter()
            .enumerate()
            .partition(|(_, gate)| self.is_gate_optimizable(gate));

        if !optimizable.is_empty() {
            formatted.push_str("// Gates with optimization potential:\n");
            for (i, gate) in optimizable {
                writeln!(
                    formatted,
                    "/* Opt {} */ {}",
                    i,
                    self.format_single_gate_compact(gate)
                )
                .expect("Writing to String cannot fail");
            }
            formatted.push('\n');
        }

        if !regular.is_empty() {
            formatted.push_str("// Regular gates:\n");
            for (i, gate) in regular {
                writeln!(
                    formatted,
                    "/* {} */ {}",
                    i,
                    self.format_single_gate_compact(gate)
                )
                .expect("Writing to String cannot fail");
            }
        }

        Ok(formatted)
    }

    /// Format in SciRS2-enhanced style
    fn format_scirs2_enhanced_sequence(
        &self,
        gates: &[QuantumGate],
    ) -> Result<String, QuantRS2Error> {
        let mut formatted = String::new();

        formatted.push_str("// SciRS2-Enhanced Quantum Circuit\n");
        formatted.push_str("// Optimized for performance and readability\n\n");

        // Analyze SIMD potential
        let simd_gates: Vec<_> = gates
            .iter()
            .enumerate()
            .filter(|(_, gate)| self.is_simd_optimizable(gate))
            .collect();

        // Analyze parallel potential
        let parallel_groups = self.find_parallel_groups(gates);

        // Format with SciRS2 annotations
        if !simd_gates.is_empty() {
            formatted.push_str("// SIMD-optimizable gates (SciRS2 enhancement available):\n");
            for (_i, gate) in simd_gates {
                writeln!(
                    formatted,
                    "simd_gate!({}); // {}",
                    self.format_single_gate_compact(gate),
                    self.get_simd_hint(gate)
                )
                .expect("Writing to String cannot fail");
            }
            formatted.push('\n');
        }

        if !parallel_groups.is_empty() {
            formatted.push_str("// Parallel execution groups:\n");
            for (group_id, group) in parallel_groups.iter().enumerate() {
                writeln!(formatted, "parallel_group!({group_id}) {{")
                    .expect("Writing to String cannot fail");
                for &gate_idx in group {
                    writeln!(
                        formatted,
                        "    {};",
                        self.format_single_gate_compact(&gates[gate_idx])
                    )
                    .expect("Writing to String cannot fail");
                }
                formatted.push_str("}\n\n");
            }
        }

        // Memory usage annotation
        if self.config.annotate_memory_usage {
            let memory_estimate = self.estimate_memory_usage(gates);
            writeln!(
                formatted,
                "// Estimated memory usage: {} KB",
                memory_estimate / 1024
            )
            .expect("Writing to String cannot fail");
        }

        Ok(formatted)
    }

    /// Check if gate is optimizable
    const fn is_gate_optimizable(&self, gate: &QuantumGate) -> bool {
        matches!(
            gate.gate_type(),
            GateType::CNOT | GateType::T | GateType::Rx(_) | GateType::Ry(_) | GateType::Rz(_)
        )
    }

    /// Check if gate is SIMD optimizable
    const fn is_simd_optimizable(&self, gate: &QuantumGate) -> bool {
        matches!(
            gate.gate_type(),
            GateType::X
                | GateType::Y
                | GateType::Z
                | GateType::H
                | GateType::Rx(_)
                | GateType::Ry(_)
                | GateType::Rz(_)
                | GateType::Phase(_)
        )
    }

    /// Get SIMD optimization hint for a gate
    const fn get_simd_hint(&self, gate: &QuantumGate) -> &'static str {
        match gate.gate_type() {
            GateType::X | GateType::Y | GateType::Z => {
                "Pauli gates benefit from SIMD vectorization"
            }
            GateType::H => "Hadamard gate can use optimized matrix-vector operations",
            GateType::Rx(_) | GateType::Ry(_) | GateType::Rz(_) => {
                "Rotation gates can use vectorized trigonometric functions"
            }
            GateType::Phase(_) => "Phase gates benefit from complex number SIMD operations",
            _ => "Consider SciRS2 optimization",
        }
    }

    /// Find groups of gates that can execute in parallel
    fn find_parallel_groups(&self, gates: &[QuantumGate]) -> Vec<Vec<usize>> {
        let mut groups = Vec::new();
        let mut used_qubits = HashSet::new();
        let mut current_group = Vec::new();

        for (i, gate) in gates.iter().enumerate() {
            let gate_qubits: HashSet<_> = gate
                .target_qubits()
                .iter()
                .chain(gate.control_qubits().unwrap_or(&[]).iter())
                .collect();

            if used_qubits.is_disjoint(&gate_qubits) {
                // Can add to current group
                current_group.push(i);
                used_qubits.extend(&gate_qubits);
            } else {
                // Start new group
                if !current_group.is_empty() {
                    groups.push(current_group);
                }
                current_group = vec![i];
                used_qubits = gate_qubits;
            }
        }

        if !current_group.is_empty() {
            groups.push(current_group);
        }

        // Only return groups with more than one gate
        groups.into_iter().filter(|group| group.len() > 1).collect()
    }

    /// Estimate memory usage for gates
    const fn estimate_memory_usage(&self, gates: &[QuantumGate]) -> usize {
        // Simplified estimation: assume each gate needs some working memory
        gates.len() * 1024 // 1KB per gate (simplified)
    }

    /// Calculate formatting statistics
    fn calculate_formatting_statistics(
        &self,
        original_circuit: &[QuantumGate],
        formatted_code: &str,
    ) -> FormattingStatistics {
        FormattingStatistics {
            original_gate_count: original_circuit.len(),
            formatted_line_count: formatted_code.lines().count(),
            compression_ratio: formatted_code.len() as f64 / (original_circuit.len() as f64 * 20.0), // Rough estimate
            readability_score: self.calculate_readability_score(formatted_code),
            optimization_annotations: formatted_code.matches("// Opt").count(),
            simd_annotations: formatted_code.matches("simd_gate!").count(),
            parallel_annotations: formatted_code.matches("parallel_group!").count(),
        }
    }

    /// Calculate readability score
    fn calculate_readability_score(&self, code: &str) -> f64 {
        let lines = code.lines().count();
        let comments = code.matches("//").count();
        let annotations = code.matches("/*").count();

        if lines == 0 {
            return 0.0;
        }

        let comment_ratio = (comments + annotations) as f64 / lines as f64;
        let line_length_variance = self.calculate_line_length_variance(code);

        // Higher comment ratio and lower line length variance = better readability
        comment_ratio
            .mul_add(0.7, (1.0 - line_length_variance) * 0.3)
            .min(1.0)
    }

    /// Calculate line length variance (normalized)
    fn calculate_line_length_variance(&self, code: &str) -> f64 {
        let lines: Vec<_> = code.lines().collect();
        if lines.is_empty() {
            return 0.0;
        }

        let lengths: Vec<f64> = lines.iter().map(|line| line.len() as f64).collect();
        let mean = lengths.iter().sum::<f64>() / lengths.len() as f64;
        let variance =
            lengths.iter().map(|len| (len - mean).powi(2)).sum::<f64>() / lengths.len() as f64;

        // Normalize variance by mean to get relative measure
        if mean > 0.0 {
            (variance.sqrt() / mean).min(1.0)
        } else {
            0.0
        }
    }

    /// Format circuit for specific output language
    pub fn format_for_language(
        &self,
        circuit: &[QuantumGate],
        language: ProgrammingLanguage,
    ) -> Result<String, QuantRS2Error> {
        match language {
            ProgrammingLanguage::Rust => self.format_for_rust(circuit),
            ProgrammingLanguage::Python => self.format_for_python(circuit),
            ProgrammingLanguage::QASM => self.format_for_qasm(circuit),
        }
    }

    /// Format for Rust
    fn format_for_rust(&self, circuit: &[QuantumGate]) -> Result<String, QuantRS2Error> {
        let mut formatted = String::new();

        formatted.push_str("// Rust quantum circuit (SciRS2 optimized)\n");
        formatted.push_str("use quantrs2_core::prelude::*;\n\n");
        formatted.push_str("fn quantum_circuit(qubits: &mut [Qubit]) -> QuantRS2Result<()> {\n");

        for gate in circuit {
            writeln!(formatted, "    {};", self.format_gate_for_rust(gate))
                .expect("Writing to String cannot fail");
        }

        formatted.push_str("    Ok(())\n");
        formatted.push_str("}\n");

        Ok(formatted)
    }

    /// Format gate for Rust
    fn format_gate_for_rust(&self, gate: &QuantumGate) -> String {
        match gate.gate_type() {
            GateType::X => format!("qubits[{}].x()", gate.target_qubits()[0]),
            GateType::Y => format!("qubits[{}].y()", gate.target_qubits()[0]),
            GateType::Z => format!("qubits[{}].z()", gate.target_qubits()[0]),
            GateType::H => format!("qubits[{}].h()", gate.target_qubits()[0]),
            GateType::CNOT => format!(
                "qubits[{}].cnot(&mut qubits[{}])",
                gate.target_qubits()[0],
                gate.target_qubits()[1]
            ),
            GateType::T => format!("qubits[{}].t()", gate.target_qubits()[0]),
            GateType::S => format!("qubits[{}].s()", gate.target_qubits()[0]),
            GateType::Rx(angle) => format!("qubits[{}].rx({})", gate.target_qubits()[0], angle),
            GateType::Ry(angle) => format!("qubits[{}].ry({})", gate.target_qubits()[0], angle),
            GateType::Rz(angle) => format!("qubits[{}].rz({})", gate.target_qubits()[0], angle),
            _ => format!("// Unsupported gate: {:?}", gate.gate_type()),
        }
    }

    /// Format for Python
    fn format_for_python(&self, circuit: &[QuantumGate]) -> Result<String, QuantRS2Error> {
        let mut formatted = String::new();

        formatted.push_str("# Python quantum circuit (SciRS2 optimized)\n");
        formatted.push_str("from quantrs2 import QuantumCircuit\n\n");
        formatted.push_str("def quantum_circuit(num_qubits):\n");
        formatted.push_str("    qc = QuantumCircuit(num_qubits)\n");

        for gate in circuit {
            writeln!(formatted, "    {}", self.format_gate_for_python(gate))
                .expect("Writing to String cannot fail");
        }

        formatted.push_str("    return qc\n");

        Ok(formatted)
    }

    /// Format gate for Python
    fn format_gate_for_python(&self, gate: &QuantumGate) -> String {
        match gate.gate_type() {
            GateType::X => format!("qc.x({})", gate.target_qubits()[0]),
            GateType::Y => format!("qc.y({})", gate.target_qubits()[0]),
            GateType::Z => format!("qc.z({})", gate.target_qubits()[0]),
            GateType::H => format!("qc.h({})", gate.target_qubits()[0]),
            GateType::CNOT => format!(
                "qc.cnot({}, {})",
                gate.target_qubits()[0],
                gate.target_qubits()[1]
            ),
            GateType::T => format!("qc.t({})", gate.target_qubits()[0]),
            GateType::S => format!("qc.s({})", gate.target_qubits()[0]),
            GateType::Rx(angle) => format!("qc.rx({}, {})", angle, gate.target_qubits()[0]),
            GateType::Ry(angle) => format!("qc.ry({}, {})", angle, gate.target_qubits()[0]),
            GateType::Rz(angle) => format!("qc.rz({}, {})", angle, gate.target_qubits()[0]),
            _ => format!("# Unsupported gate: {:?}", gate.gate_type()),
        }
    }

    /// Format for QASM
    fn format_for_qasm(&self, circuit: &[QuantumGate]) -> Result<String, QuantRS2Error> {
        let mut formatted = String::new();

        formatted.push_str("OPENQASM 2.0;\n");
        formatted.push_str("include \"qelib1.inc\";\n\n");

        // Find max qubit index
        let max_qubit = circuit
            .iter()
            .flat_map(|gate| gate.target_qubits().iter())
            .max()
            .unwrap_or(&0);

        writeln!(formatted, "qreg q[{}];", max_qubit + 1).expect("Writing to String cannot fail");
        writeln!(formatted, "creg c[{}];\n", max_qubit + 1).expect("Writing to String cannot fail");

        for gate in circuit {
            writeln!(formatted, "{};", self.format_gate_for_qasm(gate))
                .expect("Writing to String cannot fail");
        }

        Ok(formatted)
    }

    /// Format gate for QASM
    fn format_gate_for_qasm(&self, gate: &QuantumGate) -> String {
        match gate.gate_type() {
            GateType::X => format!("x q[{}]", gate.target_qubits()[0]),
            GateType::Y => format!("y q[{}]", gate.target_qubits()[0]),
            GateType::Z => format!("z q[{}]", gate.target_qubits()[0]),
            GateType::H => format!("h q[{}]", gate.target_qubits()[0]),
            GateType::CNOT => format!(
                "cx q[{}],q[{}]",
                gate.target_qubits()[0],
                gate.target_qubits()[1]
            ),
            GateType::T => format!("t q[{}]", gate.target_qubits()[0]),
            GateType::S => format!("s q[{}]", gate.target_qubits()[0]),
            GateType::Rx(angle) => format!("rx({}) q[{}]", angle, gate.target_qubits()[0]),
            GateType::Ry(angle) => format!("ry({}) q[{}]", angle, gate.target_qubits()[0]),
            GateType::Rz(angle) => format!("rz({}) q[{}]", angle, gate.target_qubits()[0]),
            _ => format!("// Unsupported gate: {:?}", gate.gate_type()),
        }
    }
}

/// Supporting data structures and enums

#[derive(Debug, Clone)]
pub enum FormattingStyle {
    Compact,
    Verbose,
    OptimizationAware,
    SciRS2Enhanced,
}

#[derive(Debug, Clone)]
pub enum ProgrammingLanguage {
    Rust,
    Python,
    QASM,
}

#[derive(Debug, Clone)]
pub struct FormattedCode {
    pub code: String,
    pub output_format: OutputFormat,
    pub analysis: CircuitAnalysis,
    pub optimizations: Vec<OptimizationOpportunity>,
    pub patterns: Vec<RecognizedPattern>,
    pub annotations: Vec<CodeAnnotation>,
    pub formatting_statistics: FormattingStatistics,
}

#[derive(Debug, Clone)]
pub struct FormattingStatistics {
    pub original_gate_count: usize,
    pub formatted_line_count: usize,
    pub compression_ratio: f64,
    pub readability_score: f64,
    pub optimization_annotations: usize,
    pub simd_annotations: usize,
    pub parallel_annotations: usize,
}

#[derive(Debug, Clone)]
pub struct CodeAnnotation {
    pub annotation_type: AnnotationType,
    pub content: String,
    pub location: AnnotationLocation,
}

#[derive(Debug, Clone)]
pub enum AnnotationType {
    Performance,
    Memory,
    SIMD,
    Parallel,
    Optimization,
    Warning,
}

#[derive(Debug, Clone)]
pub enum AnnotationLocation {
    BeforeLine(usize),
    AfterLine(usize),
    InlineComment(usize),
    BlockComment(usize, usize),
}

// Placeholder implementations for supporting modules

#[derive(Debug)]
pub struct CircuitAnalyzer {}

impl CircuitAnalyzer {
    pub const fn new() -> Self {
        Self {}
    }

    pub fn analyze_circuit(
        &self,
        _circuit: &[QuantumGate],
        _num_qubits: usize,
    ) -> Result<CircuitAnalysis, QuantRS2Error> {
        Ok(CircuitAnalysis::default())
    }
}

#[derive(Debug, Clone)]
pub struct CircuitAnalysis {
    pub gate_count: usize,
    pub depth: usize,
    pub qubit_count: usize,
    pub complexity_score: f64,
}

impl Default for CircuitAnalysis {
    fn default() -> Self {
        Self {
            gate_count: 0,
            depth: 0,
            qubit_count: 0,
            complexity_score: 0.0,
        }
    }
}

#[derive(Debug)]
pub struct OptimizationDetector {}

impl OptimizationDetector {
    pub const fn new() -> Self {
        Self {}
    }

    pub const fn detect_optimizations(
        &self,
        _circuit: &[QuantumGate],
        _analysis: &CircuitAnalysis,
    ) -> Result<Vec<OptimizationOpportunity>, QuantRS2Error> {
        Ok(vec![])
    }
}

#[derive(Debug, Clone)]
pub struct OptimizationOpportunity {
    pub opportunity_type: String,
    pub description: String,
    pub expected_improvement: f64,
}

#[derive(Debug)]
pub struct PatternRecognizer {}

impl PatternRecognizer {
    pub const fn new() -> Self {
        Self {}
    }

    pub const fn recognize_patterns(
        &self,
        _circuit: &[QuantumGate],
    ) -> Result<Vec<RecognizedPattern>, QuantRS2Error> {
        Ok(vec![])
    }
}

#[derive(Debug, Clone)]
pub struct RecognizedPattern {
    pub pattern_type: String,
    pub gates: Vec<usize>,
    pub compact_representation: String,
}

#[derive(Debug)]
pub struct LayoutOptimizer {}

impl LayoutOptimizer {
    pub const fn new() -> Self {
        Self {}
    }

    pub fn optimize_layout(
        &self,
        circuit: &[QuantumGate],
        _analysis: &CircuitAnalysis,
        _patterns: &[RecognizedPattern],
    ) -> Result<LayoutStructure, QuantRS2Error> {
        Ok(LayoutStructure {
            sections: vec![LayoutSection {
                section_type: "main".to_string(),
                gates: (0..circuit.len()).collect(),
                formatting_hint: "standard".to_string(),
            }],
        })
    }
}

#[derive(Debug, Clone)]
pub struct LayoutStructure {
    pub sections: Vec<LayoutSection>,
}

#[derive(Debug, Clone)]
pub struct LayoutSection {
    pub section_type: String,
    pub gates: Vec<usize>,
    pub formatting_hint: String,
}

#[derive(Debug)]
pub struct AnnotationGenerator {}

impl AnnotationGenerator {
    pub const fn new() -> Self {
        Self {}
    }

    pub const fn generate_annotations(
        &self,
        _circuit: &[QuantumGate],
        _analysis: &CircuitAnalysis,
        _optimizations: &[OptimizationOpportunity],
    ) -> Result<Vec<CodeAnnotation>, QuantRS2Error> {
        Ok(vec![])
    }
}

#[derive(Debug)]
pub struct StyleEngine {}

impl StyleEngine {
    pub const fn new() -> Self {
        Self {}
    }

    pub fn apply_styling(
        &self,
        layout: &LayoutStructure,
        _annotations: &[CodeAnnotation],
        _format: &OutputFormat,
        _config: &FormattingConfig,
    ) -> Result<String, QuantRS2Error> {
        // Simple placeholder implementation
        Ok(format!(
            "// Formatted circuit with {} sections",
            layout.sections.len()
        ))
    }
}

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

    #[test]
    fn test_formatter_creation() {
        let formatter = SciRS2QuantumFormatter::new();
        assert!(formatter.config.optimization_aware_formatting);
    }

    #[test]
    fn test_compact_formatting() {
        let formatter = SciRS2QuantumFormatter::new();
        let gates = vec![
            QuantumGate::new(GateType::H, vec![0], None),
            QuantumGate::new(GateType::CNOT, vec![0, 1], None),
        ];

        let formatted = formatter
            .format_gate_sequence(&gates, FormattingStyle::Compact)
            .expect("Failed to format compact sequence");
        assert!(formatted.contains("H(0)"));
        assert!(formatted.contains("CNOT(0, 1)"));
    }

    #[test]
    fn test_verbose_formatting() {
        let formatter = SciRS2QuantumFormatter::new();
        let gates = vec![QuantumGate::new(GateType::X, vec![0], None)];

        let formatted = formatter
            .format_gate_sequence(&gates, FormattingStyle::Verbose)
            .expect("Failed to format verbose sequence");
        assert!(formatted.contains("Pauli-X"));
        assert!(formatted.contains("Step 1"));
    }

    #[test]
    fn test_rust_language_formatting() {
        let formatter = SciRS2QuantumFormatter::new();
        let gates = vec![
            QuantumGate::new(GateType::H, vec![0], None),
            QuantumGate::new(GateType::X, vec![1], None),
        ];

        let formatted = formatter
            .format_for_language(&gates, ProgrammingLanguage::Rust)
            .expect("Failed to format for Rust");
        assert!(formatted.contains("use quantrs2_core::prelude::*"));
        assert!(formatted.contains("qubits[0].h()"));
        assert!(formatted.contains("qubits[1].x()"));
    }

    #[test]
    fn test_python_language_formatting() {
        let formatter = SciRS2QuantumFormatter::new();
        let gates = vec![QuantumGate::new(GateType::H, vec![0], None)];

        let formatted = formatter
            .format_for_language(&gates, ProgrammingLanguage::Python)
            .expect("Failed to format for Python");
        assert!(formatted.contains("from quantrs2 import QuantumCircuit"));
        assert!(formatted.contains("qc.h(0)"));
    }

    #[test]
    fn test_qasm_language_formatting() {
        let formatter = SciRS2QuantumFormatter::new();
        let gates = vec![
            QuantumGate::new(GateType::H, vec![0], None),
            QuantumGate::new(GateType::CNOT, vec![0, 1], None),
        ];

        let formatted = formatter
            .format_for_language(&gates, ProgrammingLanguage::QASM)
            .expect("Failed to format for QASM");
        assert!(formatted.contains("OPENQASM 2.0"));
        assert!(formatted.contains("h q[0]"));
        assert!(formatted.contains("cx q[0],q[1]"));
    }

    #[test]
    fn test_simd_optimization_detection() {
        let formatter = SciRS2QuantumFormatter::new();
        let h_gate = QuantumGate::new(GateType::H, vec![0], None);
        let cnot_gate = QuantumGate::new(GateType::CNOT, vec![0, 1], None);

        assert!(formatter.is_simd_optimizable(&h_gate));
        assert!(!formatter.is_simd_optimizable(&cnot_gate));
    }

    #[test]
    fn test_parallel_group_detection() {
        let formatter = SciRS2QuantumFormatter::new();
        let gates = vec![
            QuantumGate::new(GateType::X, vec![0], None),
            QuantumGate::new(GateType::Y, vec![1], None), // Can run in parallel with X(0)
            QuantumGate::new(GateType::CNOT, vec![0, 1], None), // Depends on both qubits
        ];

        let groups = formatter.find_parallel_groups(&gates);
        assert_eq!(groups.len(), 1);
        assert_eq!(groups[0], vec![0, 1]); // First two gates can run in parallel
    }

    #[test]
    fn test_memory_usage_estimation() {
        let formatter = SciRS2QuantumFormatter::new();
        let gates = vec![
            QuantumGate::new(GateType::H, vec![0], None),
            QuantumGate::new(GateType::X, vec![1], None),
        ];

        let memory = formatter.estimate_memory_usage(&gates);
        assert_eq!(memory, 2048); // 2 gates * 1024 bytes each
    }

    #[test]
    fn test_readability_score_calculation() {
        let formatter = SciRS2QuantumFormatter::new();
        let code_with_comments = "// This is a comment\nx(0);\n// Another comment\ny(1);";
        let code_without_comments = "x(0);\ny(1);";

        let score_with = formatter.calculate_readability_score(code_with_comments);
        let score_without = formatter.calculate_readability_score(code_without_comments);

        assert!(score_with > score_without);
    }
}