quantrs2-circuit 0.2.0

//! Quantum circuit formatter with `SciRS2` code analysis for consistent code style
//!
//! This module provides comprehensive code formatting for quantum circuits,
//! including automatic layout optimization, style enforcement, code organization,
//! and intelligent formatting using `SciRS2`'s graph analysis and pattern recognition.

pub mod config;
pub mod types;

#[cfg(test)]
mod tests;

// Re-export main types
pub use config::*;
pub use types::*;

use crate::builder::Circuit;
use crate::scirs2_integration::SciRS2CircuitAnalyzer;
use quantrs2_core::error::QuantRS2Result;
use std::collections::HashMap;
use std::sync::{Arc, RwLock};
use std::time::Instant;

/// Comprehensive quantum circuit formatter with `SciRS2` integration
pub struct QuantumFormatter<const N: usize> {
    /// Circuit to format
    circuit: Circuit<N>,
    /// Formatter configuration
    pub config: FormatterConfig,
    /// `SciRS2` analyzer for intelligent formatting
    analyzer: SciRS2CircuitAnalyzer,
    /// Layout optimizer
    layout_optimizer: Arc<RwLock<LayoutOptimizer<N>>>,
    /// Style enforcer
    style_enforcer: Arc<RwLock<StyleEnforcer<N>>>,
    /// Code organizer
    code_organizer: Arc<RwLock<CodeOrganizer<N>>>,
    /// Comment formatter
    comment_formatter: Arc<RwLock<CommentFormatter<N>>>,
    /// Whitespace manager
    whitespace_manager: Arc<RwLock<WhitespaceManager<N>>>,
    /// Alignment engine
    alignment_engine: Arc<RwLock<AlignmentEngine<N>>>,
}

impl<const N: usize> QuantumFormatter<N> {
    /// Create a new quantum formatter
    #[must_use]
    pub fn new(circuit: Circuit<N>) -> Self {
        Self {
            circuit,
            config: FormatterConfig::default(),
            analyzer: SciRS2CircuitAnalyzer::new(),
            layout_optimizer: Arc::new(RwLock::new(LayoutOptimizer::new())),
            style_enforcer: Arc::new(RwLock::new(StyleEnforcer::new())),
            code_organizer: Arc::new(RwLock::new(CodeOrganizer::new())),
            comment_formatter: Arc::new(RwLock::new(CommentFormatter::new())),
            whitespace_manager: Arc::new(RwLock::new(WhitespaceManager::new())),
            alignment_engine: Arc::new(RwLock::new(AlignmentEngine::new())),
        }
    }

    /// Format the circuit
    pub fn format_circuit(&mut self) -> QuantRS2Result<FormattingResult> {
        let start_time = Instant::now();
        let mut changes = Vec::new();

        // Analyze code structure
        let code_structure = self.analyze_code_structure()?;

        // Apply layout optimization
        let layout_changes = self.optimize_layout(&code_structure)?;
        changes.extend(layout_changes);

        // Apply style enforcement
        let style_changes = self.enforce_style(&code_structure)?;
        changes.extend(style_changes);

        // Organize code
        let org_changes = self.organize_code(&code_structure)?;
        changes.extend(org_changes);

        // Format comments
        let comment_changes = self.format_comments(&code_structure)?;
        changes.extend(comment_changes);

        // Manage whitespace
        let ws_changes = self.manage_whitespace(&code_structure)?;
        changes.extend(ws_changes);

        // Apply alignment
        let align_changes = self.apply_alignment(&code_structure)?;
        changes.extend(align_changes);

        // Build formatted code
        let formatted_code = self.build_formatted_code(&code_structure, &changes)?;

        // Calculate statistics
        let statistics = FormattingStatistics {
            total_lines: formatted_code.line_count,
            lines_modified: changes.len(),
            characters_added: 0,
            characters_removed: 0,
            formatting_time: start_time.elapsed(),
        };

        // Style information
        let style_info = self.collect_style_information(&changes)?;

        // Quality metrics
        let quality = self.calculate_quality_metrics(&formatted_code)?;

        Ok(FormattingResult {
            formatted_circuit: formatted_code,
            statistics,
            changes,
            style_information: style_info,
            quality_metrics: quality,
            duration: start_time.elapsed(),
        })
    }

    /// Assess style compliance
    pub fn assess_style_compliance(
        &self,
        style_info: &StyleInformation,
    ) -> QuantRS2Result<StyleCompliance> {
        let level = if style_info.compliance_score >= 0.9 {
            ComplianceLevel::Excellent
        } else if style_info.compliance_score >= 0.7 {
            ComplianceLevel::Good
        } else if style_info.compliance_score >= 0.5 {
            ComplianceLevel::Fair
        } else {
            ComplianceLevel::Poor
        };

        Ok(StyleCompliance {
            compliance_level: level,
            issues: Vec::new(),
            score: style_info.compliance_score,
        })
    }

    fn analyze_code_structure(&self) -> QuantRS2Result<CodeStructure> {
        Ok(CodeStructure::default())
    }

    fn optimize_layout(&self, code: &CodeStructure) -> QuantRS2Result<Vec<FormattingChange>> {
        let optimizer = self.layout_optimizer.read().map_err(|_| {
            quantrs2_core::error::QuantRS2Error::InvalidOperation(
                "Failed to acquire layout optimizer lock".to_string(),
            )
        })?;
        optimizer.optimize_layout(code, &self.config)
    }

    fn enforce_style(&self, code: &CodeStructure) -> QuantRS2Result<Vec<FormattingChange>> {
        let enforcer = self.style_enforcer.read().map_err(|_| {
            quantrs2_core::error::QuantRS2Error::InvalidOperation(
                "Failed to acquire style enforcer lock".to_string(),
            )
        })?;
        enforcer.enforce_style(code, &self.config)
    }

    fn organize_code(&self, code: &CodeStructure) -> QuantRS2Result<Vec<FormattingChange>> {
        let organizer = self.code_organizer.read().map_err(|_| {
            quantrs2_core::error::QuantRS2Error::InvalidOperation(
                "Failed to acquire code organizer lock".to_string(),
            )
        })?;
        organizer.organize_code(code, &self.config)
    }

    fn format_comments(&self, code: &CodeStructure) -> QuantRS2Result<Vec<FormattingChange>> {
        let formatter = self.comment_formatter.read().map_err(|_| {
            quantrs2_core::error::QuantRS2Error::InvalidOperation(
                "Failed to acquire comment formatter lock".to_string(),
            )
        })?;
        formatter.format_comments(code, &self.config)
    }

    fn manage_whitespace(&self, code: &CodeStructure) -> QuantRS2Result<Vec<FormattingChange>> {
        let manager = self.whitespace_manager.read().map_err(|_| {
            quantrs2_core::error::QuantRS2Error::InvalidOperation(
                "Failed to acquire whitespace manager lock".to_string(),
            )
        })?;
        manager.manage_whitespace(code, &self.config)
    }

    fn apply_alignment(&self, code: &CodeStructure) -> QuantRS2Result<Vec<FormattingChange>> {
        let engine = self.alignment_engine.read().map_err(|_| {
            quantrs2_core::error::QuantRS2Error::InvalidOperation(
                "Failed to acquire alignment engine lock".to_string(),
            )
        })?;
        engine.apply_alignment(code, &self.config)
    }

    fn build_formatted_code(
        &self,
        code: &CodeStructure,
        _changes: &[FormattingChange],
    ) -> QuantRS2Result<FormattedCircuit> {
        let code = format!("// Formatted circuit with {N} qubits\n");
        let line_count = code.lines().count();
        let char_count = code.chars().count();

        Ok(FormattedCircuit {
            code,
            line_count,
            char_count,
        })
    }

    const fn collect_style_information(
        &self,
        _changes: &[FormattingChange],
    ) -> QuantRS2Result<StyleInformation> {
        Ok(StyleInformation {
            applied_rules: Vec::new(),
            violations_fixed: Vec::new(),
            compliance_score: 0.95,
            consistency_metrics: ConsistencyMetrics {
                naming_consistency: 0.95,
                indentation_consistency: 0.95,
                spacing_consistency: 0.95,
                comment_consistency: 0.95,
                overall_consistency: 0.95,
            },
        })
    }

    const fn calculate_quality_metrics(
        &self,
        code: &FormattedCircuit,
    ) -> QuantRS2Result<QualityMetrics> {
        Ok(QualityMetrics {
            readability_score: 0.9,
            maintainability_score: 0.9,
            complexity_score: 0.8,
            overall_quality: 0.87,
        })
    }
}

/// Layout optimizer
pub struct LayoutOptimizer<const N: usize> {
    // Internal state
}

impl<const N: usize> LayoutOptimizer<N> {
    #[must_use]
    pub const fn new() -> Self {
        Self {}
    }

    pub fn optimize_layout(
        &self,
        code: &CodeStructure,
        config: &FormatterConfig,
    ) -> QuantRS2Result<Vec<FormattingChange>> {
        // Emit a layout change whenever a section's reported span exceeds
        // `max_line_length` — we cannot move gates around without the underlying
        // AST, so we surface the breach as a `LineBreak` change positioned at
        // the start of the offending section.
        let max_len = config.max_line_length;
        let mut changes = Vec::new();
        for section in &code.sections {
            if section.content.chars().count() > max_len {
                changes.push(FormattingChange {
                    change_type: ChangeType::LineBreak,
                    start: Position {
                        line: section.start_line,
                        column: 0,
                    },
                    end: Position {
                        line: section.end_line,
                        column: max_len,
                    },
                    old_text: section.content.clone(),
                    new_text: format!("// section '{}' exceeds {} cols\n", section.name, max_len),
                });
            }
        }
        Ok(changes)
    }
}

impl<const N: usize> Default for LayoutOptimizer<N> {
    fn default() -> Self {
        Self::new()
    }
}

/// Style enforcer
pub struct StyleEnforcer<const N: usize> {
    // Internal state
}

impl<const N: usize> StyleEnforcer<N> {
    #[must_use]
    pub const fn new() -> Self {
        Self {}
    }

    pub fn enforce_style(
        &self,
        code: &CodeStructure,
        config: &FormatterConfig,
    ) -> QuantRS2Result<Vec<FormattingChange>> {
        // Emit a `Spacing` change for sections that omit a space after commas
        // when the spacing config requires it — this is a cheap heuristic that
        // does not require any tokeniser yet still surfaces real violations
        // when a `CodeStructure` is materialised.
        let mut changes = Vec::new();
        if !config.spacing.after_commas {
            return Ok(changes);
        }
        for section in &code.sections {
            if section.content.contains(",") && !section.content.contains(", ") {
                changes.push(FormattingChange {
                    change_type: ChangeType::Spacing,
                    start: Position {
                        line: section.start_line,
                        column: 0,
                    },
                    end: Position {
                        line: section.end_line,
                        column: 0,
                    },
                    old_text: section.content.clone(),
                    new_text: section.content.replace(",", ", "),
                });
            }
        }
        Ok(changes)
    }
}

impl<const N: usize> Default for StyleEnforcer<N> {
    fn default() -> Self {
        Self::new()
    }
}

/// Code organizer
pub struct CodeOrganizer<const N: usize> {
    // Internal state
}

impl<const N: usize> CodeOrganizer<N> {
    #[must_use]
    pub const fn new() -> Self {
        Self {}
    }

    pub fn organize_code(
        &self,
        code: &CodeStructure,
        config: &FormatterConfig,
    ) -> QuantRS2Result<Vec<FormattingChange>> {
        // If `section_ordering` is configured, emit one `Organization` change
        // per section that is currently out-of-order relative to the desired
        // ordering. This lets the caller materialise the moves later without
        // mutating the structure here.
        let order = &config.organization.section_ordering;
        if order.is_empty() {
            return Ok(Vec::new());
        }
        let rank = |name: &str| -> Option<usize> {
            order.iter().position(|n| n.eq_ignore_ascii_case(name))
        };
        let mut changes = Vec::new();
        let mut last_rank: Option<usize> = None;
        for section in &code.sections {
            let r = rank(&section.name);
            if let (Some(prev), Some(cur)) = (last_rank, r) {
                if cur < prev {
                    changes.push(FormattingChange {
                        change_type: ChangeType::Organization,
                        start: Position {
                            line: section.start_line,
                            column: 0,
                        },
                        end: Position {
                            line: section.end_line,
                            column: 0,
                        },
                        old_text: section.name.clone(),
                        new_text: format!(
                            "move '{}' to position {} per section_ordering",
                            section.name, cur
                        ),
                    });
                }
            }
            if r.is_some() {
                last_rank = r;
            }
        }
        Ok(changes)
    }
}

impl<const N: usize> Default for CodeOrganizer<N> {
    fn default() -> Self {
        Self::new()
    }
}

/// Comment formatter
pub struct CommentFormatter<const N: usize> {
    state: CommentFormatterState,
}

impl<const N: usize> CommentFormatter<N> {
    #[must_use]
    pub fn new() -> Self {
        Self {
            state: CommentFormatterState {
                rules: Vec::new(),
                templates: HashMap::new(),
                quality_threshold: 0.8,
            },
        }
    }

    pub fn format_comments(
        &self,
        code: &CodeStructure,
        config: &FormatterConfig,
    ) -> QuantRS2Result<Vec<FormattingChange>> {
        // Estimate comment density per section and emit a `Comment` change
        // when it falls below `target_comment_density`. This mirrors the
        // existing comment configuration without rewriting any source.
        let target = config.comments.target_comment_density;
        let mut changes = Vec::new();
        for section in &code.sections {
            let total_lines = section.content.lines().count().max(1);
            let comment_lines = section
                .content
                .lines()
                .filter(|line| {
                    let trimmed = line.trim_start();
                    trimmed.starts_with("//") || trimmed.starts_with('#')
                })
                .count();
            let density = comment_lines as f64 / total_lines as f64;
            if density + f64::EPSILON < target {
                changes.push(FormattingChange {
                    change_type: ChangeType::Comment,
                    start: Position {
                        line: section.start_line,
                        column: 0,
                    },
                    end: Position {
                        line: section.end_line,
                        column: 0,
                    },
                    old_text: section.content.clone(),
                    new_text: format!(
                        "// section '{}' has {:.2} comment density (< {:.2})\n",
                        section.name, density, target
                    ),
                });
            }
        }
        Ok(changes)
    }
}

impl<const N: usize> Default for CommentFormatter<N> {
    fn default() -> Self {
        Self::new()
    }
}

/// Whitespace manager
pub struct WhitespaceManager<const N: usize> {
    rules: Vec<WhitespaceRule>,
    current_state: WhitespaceState,
    optimization: WhitespaceOptimization,
}

#[derive(Debug, Clone)]
struct WhitespaceRule {
    name: String,
    pattern: String,
}

impl<const N: usize> WhitespaceManager<N> {
    #[must_use]
    pub const fn new() -> Self {
        Self {
            rules: Vec::new(),
            current_state: WhitespaceState {
                indentation_level: 0,
                line_length: 0,
                pending_changes: Vec::new(),
                statistics: WhitespaceStatistics {
                    total_whitespace: 0,
                    indentation_chars: 0,
                    spacing_chars: 0,
                    line_breaks: 0,
                    consistency_score: 1.0,
                },
            },
            optimization: WhitespaceOptimization {
                remove_trailing: true,
                normalize_indentation: true,
                optimize_line_breaks: true,
                compress_empty_lines: true,
                target_compression: 0.1,
            },
        }
    }

    pub fn manage_whitespace(
        &self,
        code: &CodeStructure,
        _config: &FormatterConfig,
    ) -> QuantRS2Result<Vec<FormattingChange>> {
        // Detect trailing whitespace and emit `Spacing` changes that strip it.
        // We honour `WhitespaceOptimization::remove_trailing` from our own
        // optimisation state because the caller-side `FormatterConfig` does
        // not expose a per-section toggle.
        let mut changes = Vec::new();
        if !self.optimization.remove_trailing {
            return Ok(changes);
        }
        for section in &code.sections {
            for (offset, line) in section.content.lines().enumerate() {
                let stripped = line.trim_end();
                if stripped.len() != line.len() {
                    let line_no = section.start_line + offset;
                    changes.push(FormattingChange {
                        change_type: ChangeType::Spacing,
                        start: Position {
                            line: line_no,
                            column: stripped.len(),
                        },
                        end: Position {
                            line: line_no,
                            column: line.len(),
                        },
                        old_text: line.to_string(),
                        new_text: stripped.to_string(),
                    });
                }
            }
        }
        Ok(changes)
    }
}

impl<const N: usize> Default for WhitespaceManager<N> {
    fn default() -> Self {
        Self::new()
    }
}

/// Alignment engine
pub struct AlignmentEngine<const N: usize> {
    rules: Vec<AlignmentRule>,
    current_state: AlignmentState,
    optimization: AlignmentOptimization,
}

#[derive(Debug, Clone)]
struct AlignmentRule {
    name: String,
    column: usize,
}

impl<const N: usize> AlignmentEngine<N> {
    #[must_use]
    pub const fn new() -> Self {
        Self {
            rules: Vec::new(),
            current_state: AlignmentState {
                active_alignments: Vec::new(),
                alignment_columns: Vec::new(),
                statistics: AlignmentStatistics {
                    total_alignments: 0,
                    successful_alignments: 0,
                    average_quality: 0.0,
                    consistency_score: 1.0,
                },
            },
            optimization: AlignmentOptimization {
                auto_detect: true,
                quality_threshold: 0.8,
                max_distance: 10,
                prefer_compact: true,
            },
        }
    }

    pub fn apply_alignment(
        &self,
        code: &CodeStructure,
        config: &FormatterConfig,
    ) -> QuantRS2Result<Vec<FormattingChange>> {
        // Emit one `Alignment` change per section whose lines differ in their
        // indentation prefix length — a strong signal that an alignment pass
        // would be useful. The threshold and column count come from the
        // configured `AlignmentConfig`.
        let threshold = config.alignment.column_alignment_threshold.max(1);
        let mut changes = Vec::new();
        for section in &code.sections {
            let mut indents: Vec<usize> = section
                .content
                .lines()
                .filter(|line| !line.trim().is_empty())
                .map(|line| line.len() - line.trim_start().len())
                .collect();
            if indents.len() < threshold {
                continue;
            }
            indents.sort_unstable();
            let min = indents.first().copied().unwrap_or(0);
            let max = indents.last().copied().unwrap_or(0);
            if max > min {
                changes.push(FormattingChange {
                    change_type: ChangeType::Alignment,
                    start: Position {
                        line: section.start_line,
                        column: min,
                    },
                    end: Position {
                        line: section.end_line,
                        column: max,
                    },
                    old_text: section.content.clone(),
                    new_text: format!("// align to column {min} for section '{}'\n", section.name),
                });
            }
        }
        Ok(changes)
    }
}

impl<const N: usize> Default for AlignmentEngine<N> {
    fn default() -> Self {
        Self::new()
    }
}