big-code-analysis 2.0.0

#![allow(
    clippy::enum_glob_use,
    clippy::too_many_lines,
    clippy::wildcard_imports
)]
#![allow(
    clippy::cast_precision_loss,
    clippy::cast_possible_truncation,
    clippy::cast_sign_loss
)]

use super::{Abc, DeclKind, Stats};
use crate::macros::{
    csharp_bool_terminal_kinds, csharp_paren_expr_kinds, csharp_prefix_unary_expr_kinds,
};
use crate::*;

fn csharp_inspect_container(container_node: &Node, conditions: &mut f64) {
    use Csharp::*;

    let mut node = *container_node;
    let mut node_kind = node.kind_id().into();

    // Seed the boolean-context flag from the parent: known-boolean
    // contexts (loop / if / binary expression) imply the contained
    // expression evaluates as a condition.
    let Some(parent) = node.parent() else { return };
    let mut has_boolean_content = match parent.kind_id().into() {
        BinaryExpression | IfStatement | WhileStatement | DoStatement | ForStatement => true,
        ConditionalExpression => node
            .previous_sibling()
            .is_none_or(|prev| !matches!(prev.kind_id().into(), QMARK | COLON)),
        _ => false,
    };

    // Walk down through `(...)` and `!...` wrappers until we either hit
    // the underlying operand or run out of nesting. The C# grammar
    // aliases each of these kinds across multiple `kind_id`s
    // (lesson #2): match every numbered variant.
    loop {
        let is_parens = matches!(node_kind, csharp_paren_expr_kinds!());
        let is_not = matches!(node_kind, csharp_prefix_unary_expr_kinds!())
            && node
                .child(0)
                .is_some_and(|c| matches!(c.kind_id().into(), BANG));

        if !is_parens && !is_not {
            break;
        }

        // A `!` wrapper proves the contained value is boolean even
        // when the parent context didn't (e.g. `return !x;`).
        if !has_boolean_content && is_not {
            has_boolean_content = true;
        }

        // Both `parenthesized_expression` and `prefix_unary_expression`
        // store their inner expression at child index 1.
        let Some(child) = node.child(1) else { break };
        node = child;
        node_kind = node.kind_id().into();

        // Found the innermost operand; count it if a boolean context
        // was established up the chain. The `csharp_bool_terminal_kinds!()`
        // set bundles invocation aliases, the `Identifier` /
        // `BooleanLiteral` leaves, and the five bool-evaluating kinds
        // restored by #372 (member access / await / cast / is-pattern /
        // element access).
        if matches!(node_kind, csharp_bool_terminal_kinds!()) {
            if has_boolean_content {
                *conditions += 1.;
            }
            break;
        }
    }
}

fn csharp_count_unary_conditions(list_node: &Node, conditions: &mut f64) {
    use Csharp::*;

    let list_kind = list_node.kind_id().into();
    let mut cursor = list_node.cursor();

    if cursor.goto_first_child() {
        loop {
            let node = cursor.node();
            let node_kind = node.kind_id().into();

            // `csharp_bool_terminal_kinds!()` bundles invocation aliases,
            // `Identifier`, `BooleanLiteral`, and the bool-evaluating
            // expression kinds restored by #372 (member access / await /
            // cast / is-pattern / element access).
            if matches!(node_kind, csharp_bool_terminal_kinds!())
                && matches!(list_kind, BinaryExpression)
            {
                *conditions += 1.;
            } else {
                csharp_inspect_container(&node, conditions);
            }

            if !cursor.goto_next_sibling() {
                break;
            }
        }
    }
}

// ABC token-level helpers for C#. Mirror of Java's helper layout with
// C#-specific deltas: every aliased kind id is matched via the
// `csharp_*_kinds!()` macros (lesson #2); `ObjectCreationExpression`
// joins `InvocationExpression*` as a branch; the `<` / `>` parent
// guard widens to `TypeArgumentList | TypeParameterList |
// FunctionPointerType`; `ConditionalExpression` replaces Java's
// `TernaryExpression`; `for_statement` exposes its condition via the
// named `condition` field rather than positional index.

fn csharp_count_token_assignment(node: &Node, stats: &mut Stats) -> bool {
    use Csharp::*;
    match node.kind_id().into() {
        STAREQ | SLASHEQ | PERCENTEQ | DASHEQ | PLUSEQ | LTLTEQ | GTGTEQ | GTGTGTEQ | AMPEQ
        | PIPEEQ | CARETEQ | QMARKQMARKEQ | PLUSPLUS | DASHDASH => {
            stats.assignments += 1.;
        }
        FieldDeclaration | LocalDeclarationStatement => {
            stats.declaration.push(DeclKind::Var);
        }
        // C# `const` modifier marks a compile-time constant — exclude
        // its initializer from the assignment count (matches Java's
        // treatment of `final`).
        Const => {
            if let Some(DeclKind::Var) = stats.declaration.last() {
                stats.declaration.push(DeclKind::Const);
            }
        }
        SEMI => {
            if let Some(DeclKind::Const | DeclKind::Var) = stats.declaration.last() {
                stats.declaration.clear();
            }
        }
        // Count `=` unless it's the initializer of a `const` declaration.
        // `None` (outside any declaration) still counts.
        EQ => {
            if !matches!(stats.declaration.last(), Some(DeclKind::Const)) {
                stats.assignments += 1.;
            }
        }
        _ => return false,
    }
    true
}

fn csharp_count_token_branch(node: &Node, stats: &mut Stats) -> bool {
    use Csharp::*;
    if matches!(
        node.kind_id().into(),
        crate::Csharp::InvocationExpression
            | crate::Csharp::InvocationExpression2
            | crate::Csharp::InvocationExpression3
            | ObjectCreationExpression
    ) {
        stats.branches += 1.;
        return true;
    }
    false
}

fn csharp_count_token_condition(node: &Node, stats: &mut Stats) -> bool {
    use Csharp::*;
    match node.kind_id().into() {
        // The statement `switch` counts its `Case` arms; the `default:`
        // arm (token `Default`, shared by both classic `default:` and
        // arrow `default ->` forms) is the unconditional fallthrough and
        // is excluded, mirroring cyclomatic's `Case`-only count and the
        // expression-arm discard rule below (issues #456, #469).
        GTEQ | LTEQ | EQEQ | BANGEQ | Else | Case | QMARK | Try | Catch => {
            stats.conditions += 1.;
        }
        // A `switch` *expression* arm (`x switch { 1 => …, _ => … }`) is a
        // decision point. The statement `switch` counts via its `Case`
        // tokens above; an expression arm carries none, so it scored zero
        // conditions before #456 even though C# cyclomatic counts it. The
        // bare-discard arm (`_ =>` / `var _ =>`, no `when` guard) is the
        // `default:` analogue and is excluded — mirroring the cyclomatic
        // gate (lesson 11).
        SwitchExpressionArm
            if !crate::metrics::cyclomatic::csharp_switch_expression_arm_is_bare_discard(node) =>
        {
            stats.conditions += 1.;
        }
        // Excludes `<` and `>` used as type-syntax delimiters: generic
        // type arguments (`Dictionary<K, V>`), type parameter
        // declarations (`class Foo<T> { }`), and the parameter-list
        // delimiters of unsafe function-pointer types
        // (`delegate*<int, int>`).
        GT | LT => {
            if let Some(parent) = node.parent()
                && !matches!(
                    parent.kind_id().into(),
                    TypeArgumentList | TypeParameterList | FunctionPointerType
                )
            {
                stats.conditions += 1.;
            }
        }
        _ => return false,
    }
    true
}

fn csharp_walk_for_conditions(node: &Node, stats: &mut Stats) {
    use Csharp::*;
    let conds = &mut stats.conditions;
    match node.kind_id().into() {
        AMPAMP | PIPEPIPE => {
            if let Some(parent) = node.parent() {
                csharp_count_unary_conditions(&parent, conds);
            }
        }
        ArgumentList => csharp_count_unary_conditions(node, conds),
        // tree-sitter-c-sharp `if_statement` / `while_statement` shape:
        // [`if`/`while`, `(`, condition, `)`, body, …]. The parens are
        // anonymous string children, NOT a wrapping
        // `parenthesized_expression` as in tree-sitter-java — so the
        // condition lives at child(2). Targeting child(1) (the literal
        // `(` token) was the #370 bug: every unary / bare-identifier
        // condition silently scored 0. See issue #370.
        IfStatement | WhileStatement => {
            if let Some(condition) = node.child(2) {
                csharp_count_condition(&condition, conds);
            }
        }
        // tree-sitter-c-sharp `do_statement` shape:
        // [`do`, body, `while`, `(`, condition, `)`, `;`]. The
        // condition lives at child(4), not child(3) (which is the
        // literal `(` token). Targeting child(3) was the second half
        // of the #370 bug.
        DoStatement => {
            if let Some(condition) = node.child(4) {
                csharp_count_condition(&condition, conds);
            }
        }
        // `return value;` — child(1) is the value expression.
        ReturnStatement => csharp_inspect_child(node, 1, conds),
        // Child 2: declarator / assignment RHS, lambda body
        // (`params => body`).
        crate::Csharp::VariableDeclarator
        | crate::Csharp::VariableDeclarator2
        | AssignmentExpression
        | LambdaExpression => csharp_inspect_child(node, 2, conds),
        ConditionalExpression => csharp_walk_conditional(node, stats),
        ForStatement => csharp_walk_for_statement(node, stats),
        _ => {}
    }
}

// `cond ? a : b` — children are [cond, ?, a, :, b]. The cond-classifier
// match is shared with `csharp_walk_for_conditions`'s `if`/`while`/`do`
// arms via `csharp_count_condition`; the two branch slots delegate to
// `csharp_inspect_container` via `csharp_inspect_child` so a parenthesised
// or `!`-prefixed branch contributes one condition just like a bare
// invocation/identifier/boolean would.
fn csharp_walk_conditional(node: &Node, stats: &mut Stats) {
    let conds = &mut stats.conditions;
    if let Some(condition) = node.child(0) {
        csharp_count_condition(&condition, conds);
    }
    csharp_inspect_child(node, 2, conds);
    csharp_inspect_child(node, 4, conds);
}

// Counts unary / single-token conditions inside `for` statements. The
// C# grammar exposes the loop condition via the named `condition` field
// on `for_statement`, so we look it up by name rather than positional
// index. Comparison-operator conditions like `i < n` are still counted
// by the standard `GT | LT | ...` arms — this only fires when the
// condition is a bare identifier, invocation, boolean literal,
// parenthesised expression, or `!`-prefixed unary expression.
fn csharp_walk_for_statement(node: &Node, stats: &mut Stats) {
    let Some(condition) = node.child_by_field_name("condition") else {
        return;
    };
    let kind = condition.kind_id().into();
    if matches!(kind, csharp_bool_terminal_kinds!()) {
        stats.conditions += 1.;
    } else if matches!(kind, csharp_paren_expr_kinds!())
        || matches!(kind, csharp_prefix_unary_expr_kinds!())
    {
        csharp_inspect_container(&condition, &mut stats.conditions);
    }
}

impl Abc for CsharpCode {
    // See `impl Abc for JavaCode` for the short-circuit-chain rationale
    // and the cross-helper-exclusivity invariant.
    fn compute<'a>(node: &Node<'a>, _code: &'a [u8], stats: &mut Stats) {
        if csharp_count_token_assignment(node, stats) {
            return;
        }
        if csharp_count_token_branch(node, stats) {
            return;
        }
        if csharp_count_token_condition(node, stats) {
            return;
        }
        csharp_walk_for_conditions(node, stats);
    }
}

// C# mirror of `java_inspect_child` / `groovy_inspect_child`: passes
// `node.child(idx)` to `csharp_inspect_container`, which is a no-op on
// kinds other than `csharp_paren_expr_kinds!()` / `!`-prefixed
// `csharp_prefix_unary_expr_kinds!()`.
fn csharp_inspect_child(node: &Node, idx: usize, conditions: &mut f64) {
    if let Some(child) = node.child(idx) {
        csharp_inspect_container(&child, conditions);
    }
}

fn csharp_count_condition(condition: &Node, conditions: &mut f64) {
    let kind = condition.kind_id().into();
    if matches!(kind, csharp_bool_terminal_kinds!()) {
        *conditions += 1.;
    } else if matches!(kind, csharp_paren_expr_kinds!())
        || matches!(kind, csharp_prefix_unary_expr_kinds!())
    {
        csharp_inspect_container(condition, conditions);
    }
}