ryo-executor 0.1.0

//! ASTRegApply implementation for rename mutations

use ryo_analysis::SymbolKind;
use ryo_mutations::basic::RenameMutation;
use ryo_mutations::MutationResult;
use ryo_source::pure::{PureItem, PureType, PureUseTree};

use crate::engine::events::ModificationType;
use crate::engine::{ASTMutationContext, ASTRegApply};

impl ASTRegApply for RenameMutation {
    fn apply_to_registry(&self, ctx: &mut ASTMutationContext) -> MutationResult {
        // O(1) lookup using pre-resolved symbol_id
        let old_path = match ctx.symbol_registry.path(self.symbol_id) {
            Some(path) => path.clone(),
            None => {
                return MutationResult {
                    mutation_type: "Rename".to_string(),
                    changes: 0,
                    description: format!("Symbol path not found for SymbolId {:?}", self.symbol_id),
                };
            }
        };

        // Get the original name from the symbol path
        let from = old_path.name().to_string();

        // Get the AST for this symbol
        let item = match ctx.ast_registry.get(self.symbol_id) {
            Some(item) => item.clone(),
            None => {
                return MutationResult {
                    mutation_type: "Rename".to_string(),
                    changes: 0,
                    description: format!("AST not found for '{}'", from),
                };
            }
        };

        // Rename the item
        let (new_item, renamed) = rename_item(item, &from, &self.to);

        let mut changes = 0;

        if renamed {
            // Update the AST registry
            ctx.set_ast(self.symbol_id, new_item);
            changes += 1;

            // Compute new path and rename the symbol in the registry
            let new_path = old_path.with_renamed_last_segment(&from, &self.to);

            // Actually rename the symbol in the registry (not just emit event)
            let _ = ctx.rename_symbol(self.symbol_id, new_path);

            // Also update any impl blocks that reference this type as self_ty
            // (e.g., `impl TodoItem { ... }` when renaming TodoItem to Task)
            let impl_updates: Vec<_> = ctx
                .symbol_registry
                .iter()
                .filter(|(id, _)| matches!(ctx.symbol_registry.kind(*id), Some(SymbolKind::Impl)))
                .filter_map(|(id, path)| {
                    if let Some(PureItem::Impl(imp)) = ctx.ast_registry.get(id) {
                        // Check if self_ty matches the renamed type
                        if imp.self_ty == from {
                            return Some((id, path.clone()));
                        }
                    }
                    None
                })
                .collect();

            for (impl_id, impl_path) in impl_updates {
                if let Some(PureItem::Impl(mut imp)) = ctx.ast_registry.get(impl_id).cloned() {
                    imp.self_ty = self.to.clone();
                    ctx.set_ast(impl_id, PureItem::Impl(imp));

                    // Also rename the impl's SymbolPath (e.g., <impl TodoItem> -> <impl Task>)
                    let old_impl_name = impl_path.name();
                    let new_impl_name = old_impl_name.replace(&from, &self.to);
                    if old_impl_name != new_impl_name {
                        let new_impl_path =
                            impl_path.with_renamed_last_segment(old_impl_name, &new_impl_name);
                        let _ = ctx.rename_symbol(impl_id, new_impl_path);
                    }

                    changes += 1;
                }
            }

            // Cascade: Update use statements and references across all modules
            changes += update_references_across_modules(ctx, &from, &self.to);
        }

        MutationResult {
            mutation_type: "Rename".to_string(),
            changes,
            description: if changes > 0 {
                format!("Renamed '{}' to '{}'", from, self.to)
            } else {
                format!("Failed to rename '{}' to '{}'", from, self.to)
            },
        }
    }
}

/// Get the name of a PureItem if it has one
fn get_item_name(item: &PureItem) -> Option<String> {
    match item {
        PureItem::Fn(f) => Some(f.name.clone()),
        PureItem::Struct(s) => Some(s.name.clone()),
        PureItem::Enum(e) => Some(e.name.clone()),
        PureItem::Const(c) => Some(c.name.clone()),
        PureItem::Static(s) => Some(s.name.clone()),
        PureItem::Type(t) => Some(t.name.clone()),
        PureItem::Trait(t) => Some(t.name.clone()),
        PureItem::Mod(m) => Some(m.name.clone()),
        // Impl blocks have names like "<impl TypeName>" or "<impl Trait for TypeName>"
        PureItem::Impl(imp) => {
            if let Some(trait_name) = &imp.trait_ {
                Some(format!("<impl {} for {}>", trait_name, imp.self_ty))
            } else {
                Some(format!("<impl {}>", imp.self_ty))
            }
        }
        _ => None,
    }
}

/// Rename an item's name field
fn rename_item(item: PureItem, from: &str, to: &str) -> (PureItem, bool) {
    match item {
        PureItem::Fn(mut f) if f.name == from => {
            f.name = to.to_string();
            (PureItem::Fn(f), true)
        }
        PureItem::Struct(mut s) if s.name == from => {
            s.name = to.to_string();
            (PureItem::Struct(s), true)
        }
        PureItem::Enum(mut e) if e.name == from => {
            e.name = to.to_string();
            (PureItem::Enum(e), true)
        }
        PureItem::Const(mut c) if c.name == from => {
            c.name = to.to_string();
            (PureItem::Const(c), true)
        }
        PureItem::Static(mut s) if s.name == from => {
            s.name = to.to_string();
            (PureItem::Static(s), true)
        }
        PureItem::Type(mut t) if t.name == from => {
            t.name = to.to_string();
            (PureItem::Type(t), true)
        }
        PureItem::Trait(mut t) if t.name == from => {
            t.name = to.to_string();
            (PureItem::Trait(t), true)
        }
        PureItem::Mod(mut m) if m.name == from => {
            m.name = to.to_string();
            (PureItem::Mod(m), true)
        }
        _ => (item, false),
    }
}

/// Update references across all modules (use statements, type references, path expressions)
fn update_references_across_modules(ctx: &mut ASTMutationContext, from: &str, to: &str) -> usize {
    let mut changes = 0;

    // Collect all module IDs that have module_items
    let module_ids: Vec<_> = ctx
        .ast_registry
        .iter_module_items()
        .map(|(id, _)| id)
        .collect();

    for module_id in module_ids {
        // Clone items to release the borrow on ctx
        let items = match ctx.ast_registry.get_module_items(module_id) {
            Some(items) => items.clone(),
            None => continue,
        };

        // Get the module path for symbol lookup
        let module_path = ctx.symbol_registry.path(module_id).cloned();

        let mut updated_items = Vec::new();
        let mut module_changed = false;

        for item in items {
            let (new_item, changed) = update_item_references(item.clone(), from, to);
            if changed {
                module_changed = true;
                changes += 1;

                // Also update the AST registry entry for this symbol
                // (FileDumper looks up AST by symbol ID, not from module_items)
                if let Some(item_name) = get_item_name(&new_item) {
                    if let Some(ref mp) = module_path {
                        if let Ok(item_path) = mp.child(&item_name) {
                            if let Some(symbol_id) = ctx.symbol_registry.lookup(&item_path) {
                                ctx.set_ast(symbol_id, new_item.clone());
                            }
                        }
                    }
                }
            }
            updated_items.push(new_item);
        }

        if module_changed {
            ctx.ast_registry.set_module_items(module_id, updated_items);
            // Emit MutationEvent so generate_affected includes this module's file
            ctx.emit_modified(module_id, ModificationType::BodyModified);
        }
    }

    changes
}

/// Update references within a single PureItem
fn update_item_references(item: PureItem, from: &str, to: &str) -> (PureItem, bool) {
    match item {
        PureItem::Use(mut u) => {
            let (new_tree, changed) = update_use_tree(u.tree, from, to);
            u.tree = new_tree;
            (PureItem::Use(u), changed)
        }
        PureItem::Fn(mut f) => {
            let mut changed = false;
            // Update parameter types
            let new_params: Vec<_> = f
                .params
                .into_iter()
                .map(|param| {
                    let (new_param, c) = update_param_type(param, from, to);
                    if c {
                        changed = true;
                    }
                    new_param
                })
                .collect();
            f.params = new_params;
            // Update return type
            if let Some(ret) = f.ret {
                let (new_ret, c) = update_type_references(ret, from, to);
                if c {
                    changed = true;
                }
                f.ret = Some(new_ret);
            }
            // Update body
            let (new_body, c) = update_block_references(f.body, from, to);
            if c {
                changed = true;
            }
            f.body = new_body;
            (PureItem::Fn(f), changed)
        }
        PureItem::Impl(mut imp) => {
            let mut changed = false;
            // Update self_ty if it matches
            if imp.self_ty == from {
                imp.self_ty = to.to_string();
                changed = true;
            }
            // Update impl items (methods)
            let mut new_items = Vec::new();
            for impl_item in imp.items {
                let (new_item, item_changed) = update_impl_item_references(impl_item, from, to);
                if item_changed {
                    changed = true;
                }
                new_items.push(new_item);
            }
            imp.items = new_items;
            (PureItem::Impl(imp), changed)
        }
        _ => (item, false),
    }
}

/// Update use tree references
fn update_use_tree(tree: PureUseTree, from: &str, to: &str) -> (PureUseTree, bool) {
    match tree {
        PureUseTree::Name(name) if name == from => (PureUseTree::Name(to.to_string()), true),
        PureUseTree::Rename { name, rename } if name == from => (
            PureUseTree::Rename {
                name: to.to_string(),
                rename,
            },
            true,
        ),
        PureUseTree::Path { path, tree } => {
            let (new_tree, changed) = update_use_tree(*tree, from, to);
            (
                PureUseTree::Path {
                    path,
                    tree: Box::new(new_tree),
                },
                changed,
            )
        }
        PureUseTree::Group(items) => {
            let mut changed = false;
            let new_items: Vec<_> = items
                .into_iter()
                .map(|t| {
                    let (new_t, c) = update_use_tree(t, from, to);
                    if c {
                        changed = true;
                    }
                    new_t
                })
                .collect();
            (PureUseTree::Group(new_items), changed)
        }
        _ => (tree, false),
    }
}

/// Update references in impl item (method)
fn update_impl_item_references(
    item: ryo_source::pure::PureImplItem,
    from: &str,
    to: &str,
) -> (ryo_source::pure::PureImplItem, bool) {
    use ryo_source::pure::PureImplItem;

    match item {
        PureImplItem::Fn(mut f) => {
            let mut changed = false;
            // Update parameter types
            let new_params: Vec<_> = f
                .params
                .into_iter()
                .map(|param| {
                    let (new_param, c) = update_param_type(param, from, to);
                    if c {
                        changed = true;
                    }
                    new_param
                })
                .collect();
            f.params = new_params;
            // Update return type
            if let Some(ret) = f.ret {
                let (new_ret, c) = update_type_references(ret, from, to);
                if c {
                    changed = true;
                }
                f.ret = Some(new_ret);
            }
            // Update body
            let (new_body, c) = update_block_references(f.body, from, to);
            if c {
                changed = true;
            }
            f.body = new_body;
            (PureImplItem::Fn(f), changed)
        }
        _ => (item, false),
    }
}

/// Update references in a block
fn update_block_references(
    mut block: ryo_source::pure::PureBlock,
    from: &str,
    to: &str,
) -> (ryo_source::pure::PureBlock, bool) {
    let mut changed = false;

    let new_stmts: Vec<_> = block
        .stmts
        .into_iter()
        .map(|stmt| {
            let (new_stmt, c) = update_stmt_references(stmt, from, to);
            if c {
                changed = true;
            }
            new_stmt
        })
        .collect();
    block.stmts = new_stmts;

    (block, changed)
}

/// Update references in a statement
fn update_stmt_references(
    stmt: ryo_source::pure::PureStmt,
    from: &str,
    to: &str,
) -> (ryo_source::pure::PureStmt, bool) {
    use ryo_source::pure::PureStmt;

    match stmt {
        PureStmt::Expr(expr) => {
            let (new_expr, changed) = update_expr_references(expr, from, to);
            (PureStmt::Expr(new_expr), changed)
        }
        PureStmt::Semi(expr) => {
            let (new_expr, changed) = update_expr_references(expr, from, to);
            (PureStmt::Semi(new_expr), changed)
        }
        PureStmt::Local { pattern, ty, init } => {
            let mut changed = false;
            // Update type annotation if present
            let new_ty = ty.map(|t| {
                let (new_t, c) = update_type_references(t, from, to);
                if c {
                    changed = true;
                }
                new_t
            });
            // Update init expression if present
            let new_init = init.map(|e| {
                let (new_e, c) = update_expr_references(e, from, to);
                if c {
                    changed = true;
                }
                new_e
            });
            (
                PureStmt::Local {
                    pattern,
                    ty: new_ty,
                    init: new_init,
                },
                changed,
            )
        }
        _ => (stmt, false),
    }
}

/// Update references in an expression
fn update_expr_references(
    expr: ryo_source::pure::PureExpr,
    from: &str,
    to: &str,
) -> (ryo_source::pure::PureExpr, bool) {
    use ryo_source::pure::PureExpr;

    match expr {
        PureExpr::Path(path) if path.contains(from) => {
            (PureExpr::Path(path.replace(from, to)), true)
        }
        PureExpr::Call { func, args } => {
            let (new_func, func_changed) = update_expr_references(*func, from, to);
            let mut args_changed = false;
            let new_args: Vec<_> = args
                .into_iter()
                .map(|a| {
                    let (new_a, c) = update_expr_references(a, from, to);
                    if c {
                        args_changed = true;
                    }
                    new_a
                })
                .collect();
            (
                PureExpr::Call {
                    func: Box::new(new_func),
                    args: new_args,
                },
                func_changed || args_changed,
            )
        }
        PureExpr::Match { expr, arms } => {
            let (new_expr, expr_changed) = update_expr_references(*expr, from, to);
            let mut arms_changed = false;
            let new_arms: Vec<_> = arms
                .into_iter()
                .map(|mut arm| {
                    // Update pattern
                    let (new_pattern, pat_changed) =
                        update_pattern_references(arm.pattern, from, to);
                    arm.pattern = new_pattern;
                    if pat_changed {
                        arms_changed = true;
                    }
                    // Update body
                    let (new_body, c) = update_expr_references(arm.body, from, to);
                    if c {
                        arms_changed = true;
                    }
                    arm.body = new_body;
                    arm
                })
                .collect();
            (
                PureExpr::Match {
                    expr: Box::new(new_expr),
                    arms: new_arms,
                },
                expr_changed || arms_changed,
            )
        }
        PureExpr::Macro {
            name,
            delimiter,
            tokens,
        } if tokens.contains(from) => {
            // Update references in macro tokens (e.g., matches!(self, Status::Completed))
            let new_tokens = tokens.replace(from, to);
            (
                PureExpr::Macro {
                    name,
                    delimiter,
                    tokens: new_tokens,
                },
                true,
            )
        }
        _ => (expr, false),
    }
}

/// Update references in a pattern
fn update_pattern_references(
    pattern: ryo_source::pure::PurePattern,
    from: &str,
    to: &str,
) -> (ryo_source::pure::PurePattern, bool) {
    use ryo_source::pure::PurePattern;

    match pattern {
        PurePattern::Path(path) if path.contains(from) => {
            (PurePattern::Path(path.replace(from, to)), true)
        }
        PurePattern::Struct { path, fields, rest } if path.contains(from) => (
            PurePattern::Struct {
                path: path.replace(from, to),
                fields,
                rest,
            },
            true,
        ),
        _ => (pattern, false),
    }
}

/// Update references in a function parameter
fn update_param_type(
    param: ryo_source::pure::PureParam,
    from: &str,
    to: &str,
) -> (ryo_source::pure::PureParam, bool) {
    use ryo_source::pure::PureParam;

    match param {
        PureParam::Typed { name, ty } => {
            let (new_ty, changed) = update_type_references(ty, from, to);
            (PureParam::Typed { name, ty: new_ty }, changed)
        }
        PureParam::SelfValue { .. } => (param, false),
    }
}

/// Update references in a type
fn update_type_references(ty: PureType, from: &str, to: &str) -> (PureType, bool) {
    match ty {
        PureType::Path(ref path) if path.contains(from) => {
            (PureType::Path(path.replace(from, to)), true)
        }
        PureType::Ref {
            lifetime,
            is_mut,
            ty,
        } => {
            let (new_ty, changed) = update_type_references(*ty, from, to);
            (
                PureType::Ref {
                    lifetime,
                    is_mut,
                    ty: Box::new(new_ty),
                },
                changed,
            )
        }
        PureType::Tuple(tys) => {
            let mut changed = false;
            let new_tys: Vec<_> = tys
                .into_iter()
                .map(|t| {
                    let (new_t, c) = update_type_references(t, from, to);
                    if c {
                        changed = true;
                    }
                    new_t
                })
                .collect();
            (PureType::Tuple(new_tys), changed)
        }
        PureType::Array { ty, len } => {
            let (new_ty, changed) = update_type_references(*ty, from, to);
            (
                PureType::Array {
                    ty: Box::new(new_ty),
                    len,
                },
                changed,
            )
        }
        PureType::Slice(ty) => {
            let (new_ty, changed) = update_type_references(*ty, from, to);
            (PureType::Slice(Box::new(new_ty)), changed)
        }
        PureType::Fn { params, ret } => {
            let mut changed = false;
            let new_params: Vec<_> = params
                .into_iter()
                .map(|t| {
                    let (new_t, c) = update_type_references(t, from, to);
                    if c {
                        changed = true;
                    }
                    new_t
                })
                .collect();
            let new_ret = ret.map(|r| {
                let (new_r, c) = update_type_references(*r, from, to);
                if c {
                    changed = true;
                }
                Box::new(new_r)
            });
            (
                PureType::Fn {
                    params: new_params,
                    ret: new_ret,
                },
                changed,
            )
        }
        PureType::ImplTrait(traits) => {
            let mut changed = false;
            let new_traits: Vec<_> = traits
                .into_iter()
                .map(|t| {
                    if t.contains(from) {
                        changed = true;
                        t.replace(from, to)
                    } else {
                        t
                    }
                })
                .collect();
            (PureType::ImplTrait(new_traits), changed)
        }
        PureType::TraitObject(traits) => {
            let mut changed = false;
            let new_traits: Vec<_> = traits
                .into_iter()
                .map(|t| {
                    if t.contains(from) {
                        changed = true;
                        t.replace(from, to)
                    } else {
                        t
                    }
                })
                .collect();
            (PureType::TraitObject(new_traits), changed)
        }
        _ => (ty, false),
    }
}