//          Copyright Brian Schott (Hackerpilot) 2014.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)

module dscanner.analysis.function_attributes;

import dscanner.analysis.base;
import dscanner.analysis.helpers;
import dparse.ast;
import dparse.lexer;
import std.stdio;
import dsymbol.scope_;

/**
 * Prefer
 * ---
 * int getStuff() const {}
 * ---
 * to
 * ---
 * const int getStuff() {}
 * ---
 */
final class FunctionAttributeCheck : BaseAnalyzer
{
	alias visit = BaseAnalyzer.visit;

	mixin AnalyzerInfo!"function_attribute_check";

	this(string fileName, const(Scope)* sc, bool skipTests = false)
	{
		super(fileName, sc, skipTests);
	}

	override void visit(const InterfaceDeclaration dec)
	{
		const t = inInterface;
		const t2 = inAggregate;
		inInterface = true;
		inAggregate = true;
		dec.accept(this);
		inInterface = t;
		inAggregate = t2;
	}

	override void visit(const ClassDeclaration dec)
	{
		const t = inInterface;
		const t2 = inAggregate;
		inInterface = false;
		inAggregate = true;
		dec.accept(this);
		inInterface = t;
		inAggregate = t2;
	}

	override void visit(const StructDeclaration dec)
	{
		const t = inInterface;
		const t2 = inAggregate;
		inInterface = false;
		inAggregate = true;
		dec.accept(this);
		inInterface = t;
		inAggregate = t2;
	}

	override void visit(const UnionDeclaration dec)
	{
		const t = inInterface;
		const t2 = inAggregate;
		inInterface = false;
		inAggregate = true;
		dec.accept(this);
		inInterface = t;
		inAggregate = t2;
	}

	override void visit(const AttributeDeclaration dec)
	{
		if (inInterface && dec.attribute.attribute == tok!"abstract")
		{
			addErrorMessage(dec.attribute, KEY, ABSTRACT_MESSAGE);
		}
	}

	override void visit(const FunctionDeclaration dec)
	{
		if (dec.parameters.parameters.length == 0 && inAggregate)
		{
			bool foundConst;
			bool foundProperty;
			foreach (attribute; dec.attributes)
				foundConst = foundConst || attribute.attribute.type == tok!"const"
					|| attribute.attribute.type == tok!"immutable"
					|| attribute.attribute.type == tok!"inout";
			foreach (attribute; dec.memberFunctionAttributes)
			{
				foundProperty = foundProperty || (attribute.atAttribute !is null
						&& attribute.atAttribute.identifier.text == "property");
				foundConst = foundConst || attribute.tokenType == tok!"const"
					|| attribute.tokenType == tok!"immutable" || attribute.tokenType == tok!"inout";
			}
			if (foundProperty && !foundConst)
			{
				auto paren = dec.parameters.tokens.length ? dec.parameters.tokens[$ - 1] : Token.init;
				auto autofixes = paren is Token.init ? null : [
					AutoFix.insertionAfter(paren, " const", "Mark function `const`"),
					AutoFix.insertionAfter(paren, " inout", "Mark function `inout`"),
					AutoFix.insertionAfter(paren, " immutable", "Mark function `immutable`"),
				];
				addErrorMessage(dec.name, KEY,
						"Zero-parameter '@property' function should be"
						~ " marked 'const', 'inout', or 'immutable'.", autofixes);
			}
		}
		dec.accept(this);
	}

	override void visit(const Declaration dec)
	{
		bool isStatic = false;
		if (dec.attributes.length == 0)
			goto end;
		foreach (attr; dec.attributes)
		{
			if (attr.attribute.type == tok!"")
				continue;
			if (attr.attribute == tok!"abstract" && inInterface)
			{
				addErrorMessage(attr.attribute, KEY, ABSTRACT_MESSAGE,
					[AutoFix.replacement(attr.attribute, "")]);
				continue;
			}
			if (attr.attribute == tok!"static")
			{
				isStatic = true;
			}
			if (dec.functionDeclaration !is null && (attr.attribute == tok!"const"
					|| attr.attribute == tok!"inout" || attr.attribute == tok!"immutable"))
			{
				import std.string : format;

				immutable string attrString = str(attr.attribute.type);
				AutoFix[] autofixes;
				if (dec.functionDeclaration.parameters)
					autofixes ~= AutoFix.replacement(
							attr.attribute, "",
							"Move " ~ str(attr.attribute.type) ~ " after parameter list")
						.concat(AutoFix.insertionAfter(
							dec.functionDeclaration.parameters.tokens[$ - 1],
							" " ~ str(attr.attribute.type)));
				if (dec.functionDeclaration.returnType)
					autofixes ~= AutoFix.insertionAfter(attr.attribute, "(", "Make return type const")
							.concat(AutoFix.insertionAfter(dec.functionDeclaration.returnType.tokens[$ - 1], ")"));
				addErrorMessage(attr.attribute, KEY, format(
							"'%s' is not an attribute of the return type."
							~ " Place it after the parameter list to clarify.",
							attrString), autofixes);
			}
		}
	end:
		if (isStatic) {
			const t = inAggregate;
			inAggregate = false;
			dec.accept(this);
			inAggregate = t;
		}
		else {
			dec.accept(this);
		}
	}

private:
	bool inInterface;
	bool inAggregate;
	enum string ABSTRACT_MESSAGE = "'abstract' attribute is redundant in interface declarations";
	enum string KEY = "dscanner.confusing.function_attributes";
}

unittest
{
	import dscanner.analysis.config : StaticAnalysisConfig, Check, disabledConfig;

	StaticAnalysisConfig sac = disabledConfig();
	sac.function_attribute_check = Check.enabled;
	assertAnalyzerWarnings(q{
		int foo() @property { return 0; }

		class ClassName {
			const int confusingConst() { return 0; } /+
			^^^^^ [warn]: 'const' is not an attribute of the return type. Place it after the parameter list to clarify. +/

			int bar() @property { return 0; } /+
			    ^^^ [warn]: Zero-parameter '@property' function should be marked 'const', 'inout', or 'immutable'. +/
			static int barStatic() @property { return 0; }
			int barConst() const @property { return 0; }
		}

		struct StructName {
			int bar() @property { return 0; } /+
			    ^^^ [warn]: Zero-parameter '@property' function should be marked 'const', 'inout', or 'immutable'. +/
			static int barStatic() @property { return 0; }
			int barConst() const @property { return 0; }
		}

		union UnionName {
			int bar() @property { return 0; } /+
			    ^^^ [warn]: Zero-parameter '@property' function should be marked 'const', 'inout', or 'immutable'. +/
			static int barStatic() @property { return 0; }
			int barConst() const @property { return 0; }
		}

		interface InterfaceName {
			int bar() @property; /+
			    ^^^ [warn]: Zero-parameter '@property' function should be marked 'const', 'inout', or 'immutable'. +/
			static int barStatic() @property { return 0; }
			int barConst() const @property;

			abstract int method(); /+
			^^^^^^^^ [warn]: 'abstract' attribute is redundant in interface declarations +/
		}
	}c, sac);


	assertAutoFix(q{
		int foo() @property { return 0; }

		class ClassName {
			const int confusingConst() { return 0; } // fix:0
			const int confusingConst() { return 0; } // fix:1

			int bar() @property { return 0; } // fix:0
			int bar() @property { return 0; } // fix:1
			int bar() @property { return 0; } // fix:2
		}

		struct StructName {
			int bar() @property { return 0; } // fix:0
		}

		union UnionName {
			int bar() @property { return 0; } // fix:0
		}

		interface InterfaceName {
			int bar() @property; // fix:0

			abstract int method(); // fix
		}
	}c, q{
		int foo() @property { return 0; }

		class ClassName {
			int confusingConst() const { return 0; } // fix:0
			const(int) confusingConst() { return 0; } // fix:1

			int bar() const @property { return 0; } // fix:0
			int bar() inout @property { return 0; } // fix:1
			int bar() immutable @property { return 0; } // fix:2
		}

		struct StructName {
			int bar() const @property { return 0; } // fix:0
		}

		union UnionName {
			int bar() const @property { return 0; } // fix:0
		}

		interface InterfaceName {
			int bar() const @property; // fix:0

			int method(); // fix
		}
	}c, sac);

	stderr.writeln("Unittest for FunctionAttributeCheck passed.");
}