// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT License.

using Microsoft.Windows.PowerShell.ScriptAnalyzer.Generic;

using System;

using System.Collections.Generic;

using System.Globalization;

using System.Management.Automation.Language;

using System.Linq;

#if !CORECLR

using System.ComponentModel.Composition;

#endif

namespace Microsoft.Windows.PowerShell.ScriptAnalyzer.BuiltinRules

{

#if !CORECLR

[Export(typeof(IScriptRule))]

#endif

/// <summary>

/// Rule that warns when reserved words are used as function names

/// </summary>

public class AvoidReservedWordsAsFunctionNames : IScriptRule

{

// The list of PowerShell reserved words.

// https://learn.microsoft.com/en-gb/powershell/module/microsoft.powershell.core/about/about_reserved_words

//

// The Below are omitted as they don't pose an issue being a function

// name:

// assembly, base, command, hidden, in, inlinescript, interface, module,

// namespace, private, public, static

static readonly HashSet<string> reservedWords = new HashSet<string>(

new[] {

"begin", "break", "catch", "class", "configuration",

"continue", "data", "define", "do",

"dynamicparam", "else", "elseif", "end",

"enum", "exit", "filter", "finally",

"for", "foreach", "from", "function",

"if", "parallel", "param", "process",

"return", "sequence", "switch",

"throw", "trap", "try", "type",

"until", "using","var", "while", "workflow"

},

StringComparer.OrdinalIgnoreCase

);

/// <summary>

/// Analyzes the PowerShell AST for uses of reserved words as function names.

/// </summary>

/// <param name="ast">The PowerShell Abstract Syntax Tree to analyze.</param>

/// <param name="fileName">The name of the file being analyzed (for diagnostic reporting).</param>

/// <returns>A collection of diagnostic records for each violation.</returns>

public IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string fileName)

{

if (ast == null)

{

throw new ArgumentNullException(Strings.NullAstErrorMessage);

}

// Find all FunctionDefinitionAst in the Ast

var functionDefinitions = ast.FindAll(

astNode => astNode is FunctionDefinitionAst,

true

).Cast<FunctionDefinitionAst>();

foreach (var function in functionDefinitions)

{

string functionName = Helper.Instance.FunctionNameWithoutScope(function.Name);

if (reservedWords.Contains(functionName))

{

yield return new DiagnosticRecord(

string.Format(

CultureInfo.CurrentCulture,

Strings.AvoidReservedWordsAsFunctionNamesError,

functionName),

Helper.Instance.GetScriptExtentForFunctionName(function) ?? function.Extent,

GetName(),

DiagnosticSeverity.Warning,

fileName

);

}

}

}

public string GetCommonName() => Strings.AvoidReservedWordsAsFunctionNamesCommonName;

public string GetDescription() => Strings.AvoidReservedWordsAsFunctionNamesDescription;

public string GetName() => string.Format(

CultureInfo.CurrentCulture,

Strings.NameSpaceFormat,

GetSourceName(),

Strings.AvoidReservedWordsAsFunctionNamesName);

public RuleSeverity GetSeverity() => RuleSeverity.Warning;

public string GetSourceName() => Strings.SourceName;

public SourceType GetSourceType() => SourceType.Builtin;

}

}