ryo-mutations 0.1.0

//! ryo-mutations: Code transformation primitives for Rust source code
//!
//! This crate provides a unified interface for AST-level mutations with
//! validation, serialization, and parallel execution support.
//!
//! ## Module Structure
//!
//! - `basic/` - Fundamental AST operations (add, remove, rename, visibility)
//! - `refactor/` - Structural transformations (extract, inline, split, merge)
//! - `idiom/` - Idiomatic Rust patterns (unwrap→?, loops→iterators, Default)
//! - `clippy/` - Clippy lint integration
//! - `analyzer/` - rust-analyzer LSP integration
//! - `debugger/` - Debug logging utilities
//!
//! ## Validation
//!
//! Mutations can be validated before execution using [`Mutation::validate`].
//! The validation result can be controlled by [`ValidationStrategy`]:
//!
//! - `AllowAll` - For FactionBoard/speculative execution (proceed regardless)
//! - `BlockFatalOnly` - For speculative execution (block only fatal errors)
//! - `BlockConflicts` - For sequential execution (block potential conflicts)
//! - `Strict` - For debugging (block all issues)

pub mod analyzer;
pub mod basic;
pub mod clippy;
pub mod debugger;
pub mod idiom;
pub mod serializable;

use ryo_source::pure::PureFile;
use serde::{Deserialize, Serialize};
use std::path::PathBuf;

// ============================================================================
// Validation Types
// ============================================================================

/// Validation severity level (ordered by severity)
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
pub enum ValidationLevel {
    /// Information only (no impact on execution)
    Info,
    /// Warning (may cause issues in parallel execution, but safe alone)
    Warning,
    /// Potential conflict with other mutations
    Conflict,
    /// Fatal error (mutation will definitely fail)
    Fatal,
}

impl ValidationLevel {
    pub fn is_fatal(&self) -> bool {
        *self == ValidationLevel::Fatal
    }

    pub fn is_blocking(&self) -> bool {
        *self >= ValidationLevel::Conflict
    }
}

/// Validation issue code for categorization
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum ValidationCode {
    // === Fatal ===
    /// Target symbol does not exist (Rename/Remove)
    TargetNotFound,
    /// Symbol already exists (Add)
    DuplicateSymbol,
    /// Generated code would fail syn parse
    InvalidSyntax,
    /// Required type/trait not found
    MissingDependency,

    // === Conflict ===
    /// Symbol is referenced elsewhere (Remove may break references)
    SymbolReferenced,
    /// Another mutation targets the same symbol
    SameSymbolTarget,
    /// Impl block target type not found in file
    ImplTargetNotFound,

    // === Warning ===
    /// Added import may be unused
    PotentiallyUnusedImport,
    /// Visibility may not be sufficient
    VisibilityMismatch,
    /// Naming convention violation
    NamingConvention,

    // === Info ===
    /// No changes would be made (already applied, etc.)
    NoOp,
    /// Symbol has no references (safe to remove)
    UnreferencedSymbol,
}

impl ValidationCode {
    /// Get the default level for this code
    pub fn default_level(&self) -> ValidationLevel {
        match self {
            // Fatal
            ValidationCode::TargetNotFound
            | ValidationCode::DuplicateSymbol
            | ValidationCode::InvalidSyntax
            | ValidationCode::MissingDependency => ValidationLevel::Fatal,

            // Conflict
            ValidationCode::SymbolReferenced
            | ValidationCode::SameSymbolTarget
            | ValidationCode::ImplTargetNotFound => ValidationLevel::Conflict,

            // Warning
            ValidationCode::PotentiallyUnusedImport
            | ValidationCode::VisibilityMismatch
            | ValidationCode::NamingConvention => ValidationLevel::Warning,

            // Info
            ValidationCode::NoOp | ValidationCode::UnreferencedSymbol => ValidationLevel::Info,
        }
    }

    /// Get a user-friendly description of this error code
    pub fn user_friendly_message(&self) -> &'static str {
        match self {
            // Fatal
            ValidationCode::TargetNotFound => {
                "The symbol you're trying to modify doesn't exist in the codebase"
            }
            ValidationCode::DuplicateSymbol => "A symbol with this name already exists",
            ValidationCode::InvalidSyntax => "The transformation would produce invalid Rust code",
            ValidationCode::MissingDependency => "A required type or trait is not available",

            // Conflict
            ValidationCode::SymbolReferenced => {
                "This symbol is used elsewhere; removing it may break other code"
            }
            ValidationCode::SameSymbolTarget => "Multiple mutations are targeting the same symbol",
            ValidationCode::ImplTargetNotFound => "The type for this impl block was not found",

            // Warning
            ValidationCode::PotentiallyUnusedImport => "This import might not be used anywhere",
            ValidationCode::VisibilityMismatch => {
                "The visibility might not be sufficient for intended usage"
            }
            ValidationCode::NamingConvention => "The name doesn't follow Rust naming conventions",

            // Info
            ValidationCode::NoOp => "No changes are needed (already in desired state)",
            ValidationCode::UnreferencedSymbol => "This symbol has no references (safe to remove)",
        }
    }

    /// Get a suggestion for how to fix this issue
    pub fn suggestion(&self) -> Option<&'static str> {
        match self {
            ValidationCode::TargetNotFound => Some(
                "Check the symbol name for typos, or use 'ryo discover' to find available symbols"
            ),
            ValidationCode::DuplicateSymbol => Some(
                "Choose a different name, or remove the existing symbol first"
            ),
            ValidationCode::InvalidSyntax => Some(
                "Review the transformation parameters; ensure the generated code is valid Rust"
            ),
            ValidationCode::MissingDependency => Some(
                "Add the required dependency to Cargo.toml, or import the type/trait"
            ),
            ValidationCode::SymbolReferenced => Some(
                "Update all references before removing, or use 'ryo graph cascade' to see impact"
            ),
            ValidationCode::SameSymbolTarget => Some(
                "Merge mutations into a single operation, or execute them sequentially"
            ),
            ValidationCode::ImplTargetNotFound => Some(
                "Ensure the target type is defined in the same file, or specify the full path"
            ),
            ValidationCode::NamingConvention => Some(
                "Use snake_case for functions/variables, PascalCase for types, SCREAMING_CASE for constants"
            ),
            // No suggestions needed for these
            ValidationCode::PotentiallyUnusedImport => None,
            ValidationCode::VisibilityMismatch => None,
            ValidationCode::NoOp => None,
            ValidationCode::UnreferencedSymbol => None,
        }
    }

    /// Get an example of correct usage (for common errors)
    pub fn example(&self) -> Option<&'static str> {
        match self {
            ValidationCode::TargetNotFound => Some(
                r#"Example: { "intent": "RenameIdent", "from": "existing_fn", "to": "new_name" }"#,
            ),
            ValidationCode::DuplicateSymbol => {
                Some(r#"Example: First rename or remove 'foo', then add the new symbol"#)
            }
            ValidationCode::NamingConvention => {
                Some(r#"Examples: fn my_function(), struct MyStruct, const MAX_SIZE"#)
            }
            _ => None,
        }
    }
}

/// A validation issue found during pre-execution validation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ValidationIssue {
    /// Severity level
    pub level: ValidationLevel,
    /// Issue code for categorization
    pub code: ValidationCode,
    /// Human-readable message
    pub message: String,
    /// Affected symbol name (if applicable)
    pub affected_symbol: Option<String>,
}

impl ValidationIssue {
    /// Create a new validation issue
    pub fn new(code: ValidationCode, message: impl Into<String>) -> Self {
        Self {
            level: code.default_level(),
            code,
            message: message.into(),
            affected_symbol: None,
        }
    }

    /// Create with a custom level (override default)
    pub fn with_level(mut self, level: ValidationLevel) -> Self {
        self.level = level;
        self
    }

    /// Add affected symbol information
    pub fn with_symbol(mut self, symbol: impl Into<String>) -> Self {
        self.affected_symbol = Some(symbol.into());
        self
    }

    // Convenience constructors for common issues
    pub fn target_not_found(symbol: &str) -> Self {
        Self::new(
            ValidationCode::TargetNotFound,
            format!("Target symbol '{}' not found", symbol),
        )
        .with_symbol(symbol)
    }

    pub fn duplicate_symbol(symbol: &str) -> Self {
        Self::new(
            ValidationCode::DuplicateSymbol,
            format!("Symbol '{}' already exists", symbol),
        )
        .with_symbol(symbol)
    }

    pub fn symbol_referenced(symbol: &str, ref_count: usize) -> Self {
        Self::new(
            ValidationCode::SymbolReferenced,
            format!(
                "Symbol '{}' is referenced {} time(s); removal may break code",
                symbol, ref_count
            ),
        )
        .with_symbol(symbol)
    }

    pub fn no_op(reason: &str) -> Self {
        Self::new(ValidationCode::NoOp, reason.to_string())
    }

    /// Format this issue as a user-friendly message with suggestions
    pub fn format_user_friendly(&self) -> String {
        let mut output = String::new();

        // Level indicator
        let level_indicator = match self.level {
            ValidationLevel::Fatal => "[ERROR]",
            ValidationLevel::Conflict => "[CONFLICT]",
            ValidationLevel::Warning => "[WARNING]",
            ValidationLevel::Info => "[INFO]",
        };

        // Main message
        output.push_str(&format!(
            "{} {}\n",
            level_indicator,
            self.code.user_friendly_message()
        ));

        // Technical details
        if let Some(ref symbol) = self.affected_symbol {
            output.push_str(&format!("  Symbol: {}\n", symbol));
        }
        if !self.message.is_empty() && self.message != self.code.user_friendly_message() {
            output.push_str(&format!("  Detail: {}\n", self.message));
        }

        // Suggestion
        if let Some(suggestion) = self.code.suggestion() {
            output.push_str(&format!("  Suggestion: {}\n", suggestion));
        }

        // Example
        if let Some(example) = self.code.example() {
            output.push_str(&format!("  {}\n", example));
        }

        output
    }
}

impl std::fmt::Display for ValidationIssue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.format_user_friendly())
    }
}

/// Validation result containing all issues
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct ValidationResult {
    pub issues: Vec<ValidationIssue>,
}

impl ValidationResult {
    pub fn new() -> Self {
        Self { issues: Vec::new() }
    }

    pub fn ok() -> Self {
        Self::new()
    }

    pub fn with_issue(mut self, issue: ValidationIssue) -> Self {
        self.issues.push(issue);
        self
    }

    pub fn add(&mut self, issue: ValidationIssue) {
        self.issues.push(issue);
    }

    pub fn is_ok(&self) -> bool {
        self.issues.is_empty()
    }

    pub fn has_fatal(&self) -> bool {
        self.issues
            .iter()
            .any(|i| i.level == ValidationLevel::Fatal)
    }

    pub fn has_conflicts(&self) -> bool {
        self.issues
            .iter()
            .any(|i| i.level >= ValidationLevel::Conflict)
    }

    pub fn has_warnings(&self) -> bool {
        self.issues
            .iter()
            .any(|i| i.level >= ValidationLevel::Warning)
    }

    pub fn max_level(&self) -> Option<ValidationLevel> {
        self.issues.iter().map(|i| i.level).max()
    }

    pub fn by_level(&self, level: ValidationLevel) -> Vec<&ValidationIssue> {
        self.issues.iter().filter(|i| i.level == level).collect()
    }

    /// Format all issues as user-friendly messages
    pub fn format_user_friendly(&self) -> String {
        if self.issues.is_empty() {
            return String::new();
        }

        let mut output = String::new();

        // Group by level for better readability
        let fatal: Vec<_> = self.by_level(ValidationLevel::Fatal);
        let conflicts: Vec<_> = self.by_level(ValidationLevel::Conflict);
        let warnings: Vec<_> = self.by_level(ValidationLevel::Warning);
        let info: Vec<_> = self.by_level(ValidationLevel::Info);

        if !fatal.is_empty() {
            output.push_str(&format!("=== {} Error(s) ===\n", fatal.len()));
            for issue in fatal {
                output.push_str(&issue.format_user_friendly());
                output.push('\n');
            }
        }

        if !conflicts.is_empty() {
            output.push_str(&format!("=== {} Conflict(s) ===\n", conflicts.len()));
            for issue in conflicts {
                output.push_str(&issue.format_user_friendly());
                output.push('\n');
            }
        }

        if !warnings.is_empty() {
            output.push_str(&format!("=== {} Warning(s) ===\n", warnings.len()));
            for issue in warnings {
                output.push_str(&issue.format_user_friendly());
                output.push('\n');
            }
        }

        if !info.is_empty() {
            output.push_str(&format!("=== {} Info ===\n", info.len()));
            for issue in info {
                output.push_str(&issue.format_user_friendly());
                output.push('\n');
            }
        }

        output
    }
}

impl std::fmt::Display for ValidationResult {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.format_user_friendly())
    }
}

/// Strategy for handling validation results
///
/// Different execution contexts require different validation strictness:
/// - FactionBoard: Each agent operates in isolation, conflicts resolved at compose time
/// - Speculative: Optimistic execution, rollback on conflict
/// - Sequential: Traditional execution, block on potential conflicts
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Serialize, Deserialize)]
pub enum ValidationStrategy {
    /// Allow all issues (for FactionBoard / fully speculative execution)
    /// Conflicts will be detected at compose/merge time
    AllowAll,

    /// Block only fatal errors (for speculative execution)
    /// Conflicts are allowed, will be resolved at merge time
    #[default]
    BlockFatalOnly,

    /// Block conflicts and fatal errors (for sequential execution)
    /// Only warnings and info are allowed
    BlockConflicts,

    /// Block all issues including warnings (for debugging / strict mode)
    Strict,
}

impl ValidationStrategy {
    /// Check if execution can proceed given the validation result
    pub fn can_proceed(&self, result: &ValidationResult) -> bool {
        match self {
            ValidationStrategy::AllowAll => true,
            ValidationStrategy::BlockFatalOnly => !result.has_fatal(),
            ValidationStrategy::BlockConflicts => !result.has_conflicts(),
            ValidationStrategy::Strict => result.is_ok(),
        }
    }

    /// Get the minimum blocking level for this strategy
    pub fn blocking_level(&self) -> Option<ValidationLevel> {
        match self {
            ValidationStrategy::AllowAll => None,
            ValidationStrategy::BlockFatalOnly => Some(ValidationLevel::Fatal),
            ValidationStrategy::BlockConflicts => Some(ValidationLevel::Conflict),
            ValidationStrategy::Strict => Some(ValidationLevel::Info),
        }
    }
}

// Re-export all mutations for convenience
// Basic mutations
pub use basic::{
    AddConstMutation, AddDeriveMutation, AddEnumMutation, AddFieldMutation, AddFunctionMutation,
    AddImplMutation, AddItemMutation, AddMatchArmMutation, AddMethodMutation, AddPureItemsMutation,
    AddStructLiteralFieldMutation, AddStructMutation, AddTypeAliasMutation, AddUseMutation,
    AddVariantMutation, ChangeVisibilityMutation, CreateModMutation, EnumToTraitMutation,
    EnumToTraitStrategy, ExtractTraitMutation, FieldInfo, InlineTraitMutation, MatchHandling,
    MoveItemMutation, RemoveConstMutation, RemoveDeriveMutation, RemoveEnumMutation,
    RemoveFieldMutation, RemoveFunctionMutation, RemoveImplMutation, RemoveItemMutation,
    RemoveMatchArmMutation, RemoveMethodMutation, RemoveModMutation,
    RemoveStructLiteralFieldMutation, RemoveStructMutation, RemoveTraitMutation,
    RemoveTypeAliasMutation, RemoveUseMutation, RemoveVariantMutation, RenameMutation,
    ReplaceMatchArmMutation, VariantInfo,
};

// Refactor mutations
// (Currently empty - use basic mutations for refactoring operations)

// Idiom mutations
pub use idiom::{
    // Tier 1: Clippy high-frequency
    AssignOpMutation,
    BoolSimplifyMutation,
    CloneOnCopyMutation,
    CollapsibleIfMutation,
    ComparisonToMethodMutation,
    // Tier 3: Code generation (Design patterns)
    DefaultMutation,
    DeriveDefaultMutation,
    FilterNextMutation,
    // Tier 2: Pattern transformations
    FindDuplicateExpressions,
    IntroduceVariableMutation,
    // Tier 4: Performance/Safety
    LockScopeMutation,
    LoopPattern,
    LoopToIteratorMutation,
    ManualMapMutation,
    MapUnwrapOrMutation,
    MatchToIfLetMutation,
    NoOpArmToTodoMutation,
    OrganizeImportsMutation,
    RedundantClosureMutation,
    UnwrapToQuestionMutation,
    UseAtomicMutation,
    UseRwLockMutation,
};

// Detection trait and types
pub use idiom::detect::{
    create_default_registry, Detect, DetectCategory, DetectLocation, DetectOperation,
    DetectOpportunity, DetectRegistry,
};

// Statement-level mutations (from basic::stmt)
pub use basic::stmt::{
    InsertPosition, InsertStatementMutation, RemoveStatementMutation, ReplaceExprAtMutation,
    ReplaceExprMutation, ReplaceStatementMutation, WrapExprMutation,
};

// Debugger mutations
pub use debugger::{
    DbgWrapMutation, DebugMarker, DebugSession, InsertInspectMutation, RemovalTarget,
    RemoveDebugLogsMutation, MARKER_PREFIX,
};

// Serializable mutation representation
pub use serializable::{SerializableMutation, ToSerializable};

/// Result of applying a mutation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MutationResult {
    pub mutation_type: String,
    pub changes: usize,
    pub description: String,
}

/// A mutation that can be applied to AST.
///
/// # Execution APIs
///
/// - **`ASTRegApply::apply_to_registry()`** (V2, preferred): Registry-based execution
///   via `ASTMutationContext`. Defined in `ryo-executor` to avoid circular dependencies.
///
/// - **`apply()`** (Legacy, deprecated): File-based execution via `&mut PureFile`.
///   Will be removed in future versions.
///
/// # Migration Guide
///
/// New mutations should implement `ASTRegApply` trait in `ryo-executor::engine`.
/// See `ryo-executor::engine::impls` for implementation examples.
pub trait Mutation: Send + Sync {
    /// Validate the mutation before applying
    ///
    /// Returns validation issues that may indicate:
    /// - Fatal errors (mutation will fail)
    /// - Conflicts (may conflict with parallel mutations)
    /// - Warnings (potential issues)
    /// - Info (informational, no impact)
    ///
    /// Default implementation returns no issues (always valid).
    fn validate(&self, _file: &PureFile) -> ValidationResult {
        ValidationResult::ok()
    }

    /// Check if this mutation can proceed with the given strategy
    fn can_proceed(&self, file: &PureFile, strategy: ValidationStrategy) -> bool {
        strategy.can_proceed(&self.validate(file))
    }

    /// Get a description of this mutation
    fn describe(&self) -> String;

    /// Get the mutation type name
    fn mutation_type(&self) -> &'static str;

    /// Clone this mutation into a new Box
    fn box_clone(&self) -> Box<dyn Mutation>;
}

/// Clone a boxed mutation
pub fn clone_mutation(mutation: &dyn Mutation) -> Box<dyn Mutation> {
    mutation.box_clone()
}

/// A collection of mutations to apply
#[derive(Debug)]
pub struct MutationBatch {
    pub mutations: Vec<Box<dyn Mutation>>,
}

// Manual Debug impl because Box<dyn Mutation> doesn't implement Debug
impl std::fmt::Debug for Box<dyn Mutation> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Mutation({})", self.mutation_type())
    }
}

impl MutationBatch {
    pub fn new() -> Self {
        Self {
            mutations: Vec::new(),
        }
    }

    pub fn with_mutation<M: Mutation + 'static>(mut self, mutation: M) -> Self {
        self.mutations.push(Box::new(mutation));
        self
    }
}

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

// Suppress unused warning when parallel feature is not enabled
#[allow(dead_code)]
fn _use_path_buf(_: PathBuf) {}