package function.builtin.special

import environment.RuntimeEnvironment
import error.ErrorManager
import function.ArgumentValidator.BadArgumentTypeException
import function.ArgumentValidator.DottedArgumentListException
import function.ArgumentValidator.TooFewArgumentsException
import function.ArgumentValidator.TooManyArgumentsException
import function.UserDefinedFunction.IllegalKeywordRestPositionException
import org.assertj.core.api.Assertions.assertThat
import org.junit.jupiter.api.Assertions.assertThrows
import org.junit.jupiter.api.Test
import testutil.LispTestInstance
import testutil.SymbolAndFunctionCleaner
import testutil.TestUtilities.assertSExpressionsMatch
import testutil.TestUtilities.evaluateString
import testutil.TestUtilities.parseString
import java.io.ByteArrayOutputStream
import java.io.PrintStream

@LispTestInstance
class DefmacroTest : SymbolAndFunctionCleaner() {

    private var outputStream = ByteArrayOutputStream()

    private fun assertSomethingPrinted() {
        assertThat(outputStream.toByteArray()).isNotEmpty()
    }

    override fun additionalSetUp() {
        outputStream.reset()
        RuntimeEnvironment.reset()
        RuntimeEnvironment.output = PrintStream(outputStream)
        RuntimeEnvironment.errorManager = ErrorManager()
        RuntimeEnvironment.warningOutputDecorator = { it }
    }

    override fun additionalTearDown() {
        RuntimeEnvironment.reset()
    }

    @Test
    fun defmacro() {
        val input = "(defmacro m () t)"

        assertSExpressionsMatch(parseString("m"), evaluateString(input))
        assertSExpressionsMatch(parseString("t"), evaluateString("(m)"))
    }

    @Test
    fun defmacroWithEmptyBody() {
        val input = "(defmacro m ())"

        assertSExpressionsMatch(parseString("m"), evaluateString(input))
        assertSExpressionsMatch(parseString("()"), evaluateString("(m)"))
    }

    @Test
    fun defmacroDoesNotEvaluateArguments() {
        evaluateString("(setq x 'grains)")
        evaluateString("(defmacro m (x))")
        evaluateString("(m (setq x 'sprouts))")

        assertSExpressionsMatch(parseString("grains"), evaluateString("x"))
    }

    @Test
    fun defmacroAdd() {
        evaluateString("(defmacro m (x) (+ (eval x) 23))")
        assertSExpressionsMatch(parseString("27"), evaluateString("(m (+ 2 2))"))
    }

    @Test
    fun defmacroSetVariable() {
        evaluateString("(defmacro m (x) (set x 23))")
        evaluateString("(m y)")
        assertSExpressionsMatch(parseString("23"), evaluateString("y"))
    }

    @Test
    fun defmacroVariableCapture() {
        evaluateString("(setq x 0)")
        evaluateString("(defmacro m (x) (set x 23))")
        evaluateString("(m x)")
        assertSExpressionsMatch(parseString("0"), evaluateString("x"))
    }

    @Test
    fun redefineMacro_DisplaysWarning() {
        val input = "(defmacro myMacro () nil)"
        evaluateString(input)
        evaluateString(input)

        assertSomethingPrinted()
    }

    @Test
    fun redefineMacro_ActuallyRedefinesSpecialFunction() {
        evaluateString("(defmacro myMacro () nil)")
        evaluateString("(defmacro myMacro () T)")

        assertSomethingPrinted()
        assertSExpressionsMatch(parseString("t"), evaluateString("(myMacro)"))
    }

    @Test
    fun defmacroWithDottedLambdaList() {
        assertThrows(DottedArgumentListException::class.java) {
            evaluateString("(funcall 'defmacro 'm (cons 'a 'b) ())")
        }
    }

    @Test
    fun defmacroWithNonSymbolName() {
        assertThrows(BadArgumentTypeException::class.java) {
            evaluateString("(defmacro 1 () ())")
        }
    }

    @Test
    fun defmacroWithBadLambdaList() {
        assertThrows(BadArgumentTypeException::class.java) {
            evaluateString("(defmacro m a ())")
        }
    }

    @Test
    fun defmacroWithTooFewArguments() {
        assertThrows(TooFewArgumentsException::class.java) {
            evaluateString("(defmacro m)")
        }
    }

    @Test
    fun defmacroAndCallWithTooFewArguments() {
        evaluateString("(defmacro m (a b))")

        assertThrows(TooFewArgumentsException::class.java) {
            evaluateString("(m a)")
        }
    }

    @Test
    fun defmacroAndCallWithTooManyArguments() {
        evaluateString("(defmacro m (a b))")

        assertThrows(TooManyArgumentsException::class.java) {
            evaluateString("(m a b c)")
        }
    }

    @Test
    fun defmacroWithKeywordRestParameter() {
        evaluateString("(defmacro m (&rest x) (car x))")
        assertSExpressionsMatch(parseString("1"), evaluateString("(m 1 2 3 4 5)"))
    }

    @Test
    fun defmacroWithNormalAndKeywordRestParameter() {
        evaluateString("(defmacro m (a &rest b) (list 'cons a (list 'quote b)))")
        assertSExpressionsMatch(parseString("(1 2 3 4 5)"), evaluateString("(m 1 2 3 4 5)"))
    }

    @Test
    fun defmacroWithParametersFollowingKeywordRest() {
        assertThrows(IllegalKeywordRestPositionException::class.java) {
            evaluateString("(defmacro m (a &rest b c) (cons a b))")
        }
    }

    @Test
    fun defmacroWithKeywordRest_CallWithNoArguments() {
        evaluateString("(defmacro m (&rest a) (car a))")
        assertSExpressionsMatch(parseString("nil"), evaluateString("(m)"))
    }

    @Test
    fun defmacroWithNormalAndKeywordRest_CallWithNoArguments() {
        evaluateString("(defmacro m (a &rest b) a)")

        assertThrows(TooFewArgumentsException::class.java) {
            evaluateString("(m)")
        }
    }

    @Test
    fun macroIsEvaluatedAfterExpansion() {
        evaluateString("(setq x 'grains)")
        evaluateString("(defmacro m (x) x)")
        evaluateString("(m (setq x 'sprouts))")

        assertSExpressionsMatch(parseString("sprouts"), evaluateString("x"))
    }

    @Test
    fun macroIsEvaluatedCorrectly() {
        evaluateString("(defmacro m (x) `'(+ 2 ,x))")
        assertSExpressionsMatch(parseString("(+ 2 25)"), evaluateString("(m 25)"))
    }
}