/* @internal */

namespace ts.Rename {

export function getRenameInfo(program: Program, sourceFile: SourceFile, position: number): RenameInfo {

const node = getTouchingPropertyName(sourceFile, position);

const renameInfo = node && nodeIsEligibleForRename(node)

? getRenameInfoForNode(node, program.getTypeChecker(), sourceFile, declaration => program.isSourceFileDefaultLibrary(declaration.getSourceFile()))

: undefined;

return renameInfo || getRenameInfoError(Diagnostics.You_cannot_rename_this_element);

}

function getRenameInfoForNode(node: Node, typeChecker: TypeChecker, sourceFile: SourceFile, isDefinedInLibraryFile: (declaration: Node) => boolean): RenameInfo | undefined {

const symbol = typeChecker.getSymbolAtLocation(node);

if (!symbol) return;

// Only allow a symbol to be renamed if it actually has at least one declaration.

const { declarations } = symbol;

if (!declarations || declarations.length === 0) return;

// Disallow rename for elements that are defined in the standard TypeScript library.

if (declarations.some(isDefinedInLibraryFile)) {

return getRenameInfoError(Diagnostics.You_cannot_rename_elements_that_are_defined_in_the_standard_TypeScript_library);

}

// Cannot rename `default` as in `import { default as foo } from "./someModule";

if (isIdentifier(node) && node.originalKeywordKind === SyntaxKind.DefaultKeyword && symbol.parent!.flags & SymbolFlags.Module) {

return undefined;

}

// Can't rename a module name.

if (isStringLiteralLike(node) && tryGetImportFromModuleSpecifier(node)) return undefined;

const kind = SymbolDisplay.getSymbolKind(typeChecker, symbol, node);

const specifierName = (isImportOrExportSpecifierName(node) || isStringOrNumericLiteral(node) && node.parent.kind === SyntaxKind.ComputedPropertyName)

? stripQuotes(getTextOfIdentifierOrLiteral(node))

: undefined;

const displayName = specifierName || typeChecker.symbolToString(symbol);

const fullDisplayName = specifierName || typeChecker.getFullyQualifiedName(symbol);

return getRenameInfoSuccess(displayName, fullDisplayName, kind, SymbolDisplay.getSymbolModifiers(symbol), node, sourceFile);

}

function getRenameInfoSuccess(displayName: string, fullDisplayName: string, kind: ScriptElementKind, kindModifiers: string, node: Node, sourceFile: SourceFile): RenameInfo {

return {

canRename: true,

kind,

displayName,

localizedErrorMessage: undefined,

fullDisplayName,

kindModifiers,

triggerSpan: createTriggerSpanForNode(node, sourceFile)

};

}

function getRenameInfoError(diagnostic: DiagnosticMessage): RenameInfo {

// TODO: GH#18217

return {

canRename: false,

localizedErrorMessage: getLocaleSpecificMessage(diagnostic),

displayName: undefined!,

fullDisplayName: undefined!,

kind: undefined!,

kindModifiers: undefined!,

triggerSpan: undefined!

};

}

function createTriggerSpanForNode(node: Node, sourceFile: SourceFile) {

let start = node.getStart(sourceFile);

let width = node.getWidth(sourceFile);

if (node.kind === SyntaxKind.StringLiteral) {

// Exclude the quotes

start += 1;

width -= 2;

}

return createTextSpan(start, width);

}

function nodeIsEligibleForRename(node: Node): boolean {

switch (node.kind) {

case SyntaxKind.Identifier:

case SyntaxKind.StringLiteral:

case SyntaxKind.ThisKeyword:

return true;

case SyntaxKind.NumericLiteral:

return isLiteralNameOfPropertyDeclarationOrIndexAccess(node as NumericLiteral);

default:

return false;

}

}

}