package prolog.builtins

import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.Assertions.assertInstanceOf
import org.junit.jupiter.api.Assertions.assertTrue
import org.junit.jupiter.api.Test
import prolog.ast.arithmetic.Integer
import prolog.ast.terms.AnonymousVariable
import prolog.ast.terms.Atom
import prolog.ast.terms.Structure
import prolog.ast.terms.Variable

class AnalysingAndConstructionOperatorsTests {
    @Test
    fun `functor(foo, foo, 0)`() {
        val functor = Functor(Atom("foo"), Atom("foo"), Integer(0))

        val result = functor.satisfy(emptyMap()).toList()

        assertEquals(1, result.size, "Expected 1 result")
        assertTrue(result[0].isSuccess, "Expected success")
        assertTrue(result[0].getOrNull()!!.isEmpty(), "Expected empty substitutions")
    }

    @Test
    fun `functor(foo(X), foo, Y)`() {
        val functor = Functor(
            Structure(Atom("foo"), listOf(Variable("X"))),
            Atom("foo"),
            Variable("Y")
        )

        val result = functor.satisfy(emptyMap()).toList()

        assertEquals(1, result.size, "Expected 1 result")
        assertTrue(result[0].isSuccess, "Expected success")
        val subs = result[0].getOrNull()!!
        assertEquals(1, subs.size, "Expected 1 substitution")
        assertEquals(Integer(1), subs[Variable("Y")])
    }

    @Test
    fun `functor(foo, X, Y)`() {
        val atom = Atom("foo")
        val functor = Functor(atom, Variable("X"), Variable("Y"))

        val result = functor.satisfy(emptyMap()).toList()

        assertEquals(1, result.size, "Expected 1 result")
        assertTrue(result[0].isSuccess, "Expected success")
        val subs = result[0].getOrNull()!!
        assertEquals(2, subs.size, "Expected 2 substitutions")
        assertEquals(atom.functor.name, subs[Variable("X")])
        assertEquals(atom.functor.arity, subs[Variable("Y")])
    }

    @Test
    fun `functor(X, foo, 1)`() {
        val functor = Functor(Variable("X"), Atom("foo"), Integer(1))

        val result = functor.satisfy(emptyMap()).toList()

        assertEquals(1, result.size, "Expected 1 result")
        assertTrue(result[0].isSuccess, "Expected success")
        val subs = result[0].getOrNull()!!
        assertEquals(1, subs.size, "Expected 1 substitution")
        assertInstanceOf(Structure::class.java, subs[Variable("X")])
        val structure = subs[Variable("X")] as Structure
        assertEquals(Atom("foo"), structure.name)
        assertEquals(1, structure.arguments.size)
        assertInstanceOf(AnonymousVariable::class.java, structure.arguments[0])
    }

    @Test
    fun `functor(foo(a), foo, 0)`() {
        val functor = Functor(Structure(Atom("foo"), listOf(Atom("a"))), Atom("foo"), Integer(0))

        val result = functor.satisfy(emptyMap()).toList()

        assertTrue(result.isEmpty(), "Expected no results")
    }

    @Test
    fun `functor(foo(X), foo, 0)`() {
        val functor = Functor(Structure(Atom("foo"), listOf(Variable("X"))), Atom("foo"), Integer(0))

        val result = functor.satisfy(emptyMap()).toList()

        assertTrue(result.isEmpty(), "Expected no results")
    }
}