package com.seaofnodes.simple;

import com.seaofnodes.simple.codegen.CodeGen;
import java.io.IOException;
import org.junit.Test;
import static org.junit.Assert.*;

public class Chapter20Test {

    @Test
    public void testJig() {
        CodeGen code = new CodeGen("return 0;");
        code.parse().opto().typeCheck();
        assertEquals("return 0;", code._stop.toString());
        assertEquals("0", Eval2.eval(code,  2));
    }

    static void testCPU( String src, String cpu, String os, int spills, String stop ) {
        CodeGen code = new CodeGen(src);
        code.driver(CodeGen.Phase.RegAlloc,cpu,os);
        int delta = spills>>3;
        if( delta==0 ) delta = 1;
        if( spills != -1 )
            assertEquals("Expect spills:",spills,code._regAlloc._spillScaled,delta);
        if( stop != null )
            assertEquals(stop, code._stop.toString());
    }

    private static void testAllCPUs( String src, int spills, String stop ) {
        testCPU(src,"x86_64_v2", "SystemV",spills,stop);
        testCPU(src,"riscv"    , "SystemV",spills,stop);
        testCPU(src,"arm"      , "SystemV",spills,stop);
    }

    @Test public void testAlloc0() {
        testCPU("return new u8[arg];","x86_64_v2", "SystemV",3,"return []u8;");
        testCPU("return new u8[arg];","riscv"    , "SystemV",5,"return []u8;");
        testCPU("return new u8[arg];","arm"      , "SystemV",5,"return []u8;");
    }

    @Test public void testBasic1() {
        String src = "return arg | 2;";
        testCPU(src,"x86_64_v2", "SystemV",1,"return (ori,mov(arg));");
        testCPU(src,"riscv"    , "SystemV",0,"return ( arg | #2 );");
        testCPU(src,"arm"      , "SystemV",0,"return (ori,arg);");
    }

    @Test
    public void testNewtonInteger() {
        String src =
"""
// Newtons approximation to the square root
val sqrt = { int x ->
    int guess = x;
    while( 1 ) {
        int next = (x/guess + guess)/2;
        if( next == guess ) return guess;
        guess = next;
    }
};
int cast_int = arg+2;
return sqrt(arg) + sqrt(cast_int);
""";
        testCPU(src,"x86_64_v2", "Win64"  ,55,null);
        testCPU(src,"riscv"    , "SystemV",19,null);
        testCPU(src,"arm"      , "SystemV",19,null);
    }

    @Test
    public void testNewtonFloat() throws IOException {
        String src =
"""
val test_sqrt = { flt x ->
    flt epsilon = 1e-15;
    flt guess = x;
    while( 1 ) {
        flt next = (x/guess + guess)/2;
        if( guess-epsilon <= next & next <= guess+epsilon ) return guess;
        //if( guess==next ) return guess;
        guess = next;
    }
};
flt farg = arg; return test_sqrt(farg) + test_sqrt(farg+2.0);
""";
        testCPU(src,"x86_64_v2", "SystemV",39,null);
        testCPU(src,"riscv"    , "SystemV",17,null);
        testCPU(src,"arm"      , "SystemV",18,null);
    }

    @Test
    public void testAlloc2() {
        String src = "int[] !xs = new int[3]; xs[arg]=1; return xs[arg&1];";
        testCPU(src,"x86_64_v2", "SystemV",-1,"return .[];");
        testCPU(src,"riscv"    , "SystemV", 6,"return .[];");
        testCPU(src,"arm"      , "SystemV", 6,"return .[];");
    }



    @Test
    public void testArray1() throws IOException {
        String src =
"""
int[] !ary = new int[arg];
// Fill [0,1,2,3,4,...]
for( int i=0; i<ary#; i++ )
    ary[i] = i;
// Fill [0,1,3,6,10,...]
for( int i=0; i<ary#-1; i++ )
    ary[i+1] += ary[i];
return ary[1] * 1000 + ary[3]; // 1 * 1000 + 6
""";
        testCPU(src,"x86_64_v2", "SystemV",-1,"return .[];");
        testCPU(src,"riscv"    , "SystemV", 8,"return (add,.[],(mul,.[],1000));");
        testCPU(src,"arm"      , "SystemV", 5,"return (add,.[],(mul,.[],1000));");
    }


    @Test
    public void testString() throws IOException {
        String src =
"""
struct String {
    u8[] cs;
    int _hashCode;
};

// Compare two Strings
val equals = { String self, String s ->
    if( self == s ) return true;
    if( self.cs# != s.cs# ) return false;
    for( int i=0; i< self.cs#; i++ )
        if( self.cs[i] != s.cs[i] )
            return false;
    return true;
};

// Return the String hashCode (cached, and never 0)
val hashCode = { String self ->
    self._hashCode
    ?  self._hashCode
    : (self._hashCode = _hashCodeString(self));
};

val _hashCodeString = { String self ->
    int hash=0;
    for( int i=0; i< self.cs#; i++ )
        hash = hash*31 + self.cs[i];
    if( !hash ) hash = 123456789;
    return hash;
};
""";
        testCPU(src,"x86_64_v2", "SystemV", 9,null);
        testCPU(src,"riscv"    , "SystemV", 3,null);
        testCPU(src,"arm"      , "SystemV", 3,null);
    }

    @Test
    public void testCast() {
        String src = "struct Bar { int x; }; var b = arg ? new Bar;  return b ? b.x++ + b.x++ : -1;";
        testCPU(src,"x86_64_v2", "SystemV",2,null);
        testCPU(src,"riscv"    , "SystemV",2,null);
        testCPU(src,"arm"      , "SystemV",2,null);
    }

    @Test
    public void testFltArg() {
        String src = "return {int i, flt f, int j->return i+f+j;};";
        testAllCPUs(src,0,null);
    }

    @Test
    public void testFlags1() {
        String src = """
bool b1 = arg == 1;
bool b2 = arg == 2;
if (b2) if (b1) return 1;
if (b1) return 2;
return 0;
""";
        testCPU(src,"x86_64_v2", "SystemV",0,"return Phi(Region,1,2,0);");
        testCPU(src,"riscv"    , "SystemV",0,"return Phi(Region,1,2,0);");
        testCPU(src,"arm"      , "SystemV",0,"return Phi(Region,1,2,0);");
    }

    @Test
    public void testFlags2() {
        String src = """
bool b1 = arg == 1;
while (arg > 0) {
    arg--;
    if (b1) arg--;
}
return arg;
""";
        testCPU(src,"x86_64_v2", "SystemV",3,null);
        testCPU(src,"riscv"    , "SystemV",2,null);
        testCPU(src,"arm"      , "SystemV",2,null);
    }
}