#include "../../../include/ground.h"
#ifndef _WIN32
#include "../../linenoise/linenoise.h"
#endif
#include <stdint.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ffi.h>

#define HEAP_GET(heap, idx) (&(heap)->heap[(idx)])
#define HEAP_SET(heap, idx, val) ((heap)->heap[(idx)] = (val))

#define CONTINUE    (struct GroundExecutionResult) { _GER_CONTINUE }
#define JUMP(idx)   (struct GroundExecutionResult) { .type = _GER_JUMP,   .as.line  = idx }
#define END(res)    (struct GroundExecutionResult) { .type = _GER_END,    .as.end   = res }
#define RETURN(val) (struct GroundExecutionResult) { .type = _GER_RETURN, .as.value = val }

static ffi_type* ffiTypeFromGroundType(GroundType* type) {
    switch (type->type) {
        case GroundType_Int: return &ffi_type_sint64;
        case GroundType_Double: return &ffi_type_double;
        case GroundType_Char: return &ffi_type_schar;
        case GroundType_Bool: return &ffi_type_uint8;
        case GroundType_String: return &ffi_type_pointer;
        default: return &ffi_type_pointer; // FIXME implement stuff for everything else
    }
}

struct GroundExecutionResult _GroundBytecodeInstructionExecute(GroundBytecodeInstruction* instruction, GroundBytecodeHeap* heap) {

    static const void* jumpTable[] = {
        &&IF, &&JUMP, &&END, 
        &&INPUT, &&PRINT, &&PRINTLN, 
        &&SET, &&GETTYPE, &&EXISTS, 
        &&SETLIST, &&SETLISTAT, &&GETLISTAT, &&GETLISTSIZE, &&LISTAPPEND,
        &&GETSTRSIZE, &&GETSTRCHARAT, 
        &&ADD, &&SUBTRACT, &&MULTIPLY, &&DIVIDE, 
        &&EQUAL, &&INEQUAL, &&NOT, &&GREATER, &&LESSER, 
        &&AND, &&OR, &&XOR, &&NEG, &&SHIFT, 
        &&STOI, &&STOD, &&ITOC, &&CTOI, &&TOSTRING, 
        &&FUN, &&RETURN, &&ENDFUN, &&CALL, &&CALLMETHOD, 
        &&STRUCT, &&ENDSTRUCT, &&INIT, &&GETFIELD, &&SETFIELD, 
        &&USE, &&EXTERN, &&CREATELABEL, 
        &&PAUSE, &&DROP, &&LICENSE, &&ERRORCMD, &&THROW, &&CATCH
    };

    goto *jumpTable[instruction->type];

    IF: {
        GroundBytecodeValue* cond = HEAP_GET(heap, instruction->args.at[0]);
        if (cond->as.Bool) {
            return JUMP(instruction->args.at[1]);
        }
        return CONTINUE;
    }
    JUMP: {
        return JUMP(instruction->args.at[0]);
    }
    END: {
        return END( HEAP_GET(heap, instruction->args.at[0])->as.Int );
    }
    INPUT: {
#ifdef _WIN32 
        // TODO implement line input on Windows
        HEAP_SET(heap, instruction->args.at[0], Ground.New.BytecodeValue(Ground.New.Value.String(Ground.New.String(""))));
        return CONTINUE;
#else
        char* input = linenoise("");
        HEAP_SET(heap, instruction->args.at[0], Ground.New.BytecodeValue(Ground.New.Value.String(Ground.New.String(input))));
        free(input);
        return CONTINUE;
#endif
    }
    PRINT: {
        for (GroundSize i = 0; i < instruction->args.len; i++) {
            printf("%s ", Ground.Stringify.BytecodeValue(HEAP_GET(heap, instruction->args.at[i])));
        }
        return CONTINUE;
    }
    PRINTLN: {
        for (GroundSize i = 0; i < instruction->args.len; i++) {
            printf("%s ", Ground.Stringify.BytecodeValue(HEAP_GET(heap, instruction->args.at[i])));
        }
        printf("\n");
        return CONTINUE;
    }
    SET: {
        if (instruction->args.at[0] != instruction->args.at[1]) {
            GroundBytecodeValue copy = Ground.Copy.BytecodeValue(HEAP_GET(heap, instruction->args.at[1]));
            Ground.Free.BytecodeValue(&heap->heap[instruction->args.at[0]]);
            HEAP_SET(heap, instruction->args.at[0], copy);
        }
        return CONTINUE;
    }
    GETTYPE: {
        Ground.Log.Warning("GETTYPE is deprecated");
        return CONTINUE;
    }
    EXISTS: {
        Ground.Log.Warning("EXISTS is deprecated");
        return CONTINUE;
    }
    SETLIST: {
        return CONTINUE;
    }
    SETLISTAT: {
        return CONTINUE;
    }
    GETLISTAT: {
        return CONTINUE;
    }
    GETLISTSIZE: {
        return CONTINUE;
    }
    LISTAPPEND: {
        return CONTINUE;
    }
    GETSTRSIZE: {
        return CONTINUE;
    }
    GETSTRCHARAT: {
        return CONTINUE;
    }
    ADD: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Int(left->as.Int + right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Int + right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid add operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double + right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double + right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid add operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            case GroundType_String: {
                switch (right->type.type) {
                    case GroundType_String: {
                        GroundSize total = left->as.String.len + right->as.String.len;
                        char* buf = malloc(total + 1);
                        if (buf == NULL) {
                            Ground.Log.Error("malloc failed (instruction ADD{string, string, dirref}) in Ground.Instruction.execute()");
                            Ground.Flags.error = true;
                            break;
                        }
                        sprintf(buf, "%s%s", left->as.String.cstr, right->as.String.cstr);
                        *final = Ground.New.BytecodeValue(Ground.New.Value.String(Ground.New.String(buf)));
                        free(buf);
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid add operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
            }
            default: {
                Ground.Log.Error("invalid add operation in Ground.Instruction.execute()");
                Ground.Flags.error = true;
                break;
            }
        }
        return CONTINUE;
    }
    SUBTRACT: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Int(left->as.Int - right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Int - right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double - right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double - right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            default: {
                Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                Ground.Flags.error = true;
                break;
            }
        }
        return CONTINUE;
    }
    MULTIPLY: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Int(left->as.Int * right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Int * right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double * right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double * right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            default: {
                Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                Ground.Flags.error = true;
                break;
            }
        }
        return CONTINUE;
    }
    DIVIDE: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Int(left->as.Int / right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Int / right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double / right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(left->as.Double / right->as.Double));
                        break;
                    }
                    default: {
                        Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                        Ground.Flags.error = true;
                        break;
                    }
                }
                break;
            }
            default: {
                Ground.Log.Error("invalid subtract operation in Ground.Instruction.execute()");
                Ground.Flags.error = true;
                break;
            }
        }
        return CONTINUE;
    }
    EQUAL: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int == right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int == right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double == right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double == right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                        break;
                    }
                }
                break;
            }
            case GroundType_Char: {
                if (right->type.type == GroundType_Char) {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Char == right->as.Char));
                } else {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                }
                break;
            }
            case GroundType_Bool: {
                if (right->type.type == GroundType_Bool) {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Bool == right->as.Bool));
                } else {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                }
                break;
            }
            case GroundType_String: {
                if (right->type.type == GroundType_String) {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(strcmp(left->as.String.cstr, right->as.String.cstr) == 0));
                } else {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                }
                break;
            }
            default: {
                *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                break;
            }
        }
        return CONTINUE;
    }
    INEQUAL: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int != right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int != right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double != right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double != right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                        break;
                    }
                }
                break;
            }
            case GroundType_Char: {
                if (right->type.type == GroundType_Char) {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Char != right->as.Char));
                } else {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                }
                break;
            }
            case GroundType_Bool: {
                if (right->type.type == GroundType_Bool) {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Bool != right->as.Bool));
                } else {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                }
                break;
            }
            case GroundType_String: {
                if (right->type.type == GroundType_String) {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(strcmp(left->as.String.cstr, right->as.String.cstr) != 0));
                } else {
                    *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                }
                break;
            }
            default: {
                *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                break;
            }
        }
        return CONTINUE;
    }
    NOT: {
        HEAP_SET(heap, instruction->args.at[1], Ground.New.BytecodeValue(Ground.New.Value.Bool(!HEAP_GET(heap, instruction->args.at[0])->as.Bool)));
        return CONTINUE;
    }
    GREATER: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int > right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int > right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double > right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double > right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                        break;
                    }
                }
                break;
            }
            default: {
                *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                break;
            }
        }
        return CONTINUE;
    }
    LESSER: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);

        switch (left->type.type) {
            case GroundType_Int: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int < right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Int < right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                        break;
                    }
                }
                break;
            }
            case GroundType_Double: {
                switch (right->type.type) {
                    case GroundType_Int: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double < right->as.Int));
                        break;
                    }
                    case GroundType_Double: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Double < right->as.Double));
                        break;
                    }
                    default: {
                        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(true));
                        break;
                    }
                }
                break;
            }
            default: {
                *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                break;
            }
        }
        return CONTINUE;
    }
    AND: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);
        
        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Bool && right->as.Bool));

        return CONTINUE;
    }
    OR: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);
        
        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Bool || right->as.Bool));

        return CONTINUE;
    }
    XOR: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[2]);
        GroundBytecodeValue* left = HEAP_GET(heap, instruction->args.at[0]);
        GroundBytecodeValue* right = HEAP_GET(heap, instruction->args.at[1]);
        
        *final = Ground.New.BytecodeValue(Ground.New.Value.Bool(left->as.Bool != right->as.Bool));

        return CONTINUE;
    }
    NEG: {
        return CONTINUE;
    }
    SHIFT: {
        return CONTINUE;
    }
    STOI: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[1]);
        GroundBytecodeValue* in = HEAP_GET(heap, instruction->args.at[0]);

        char* status = NULL;

        *final = Ground.New.BytecodeValue(Ground.New.Value.Int(strtoll(in->as.String.cstr, &status, 0)));

        if (status != in->as.String.cstr) {
            Ground.Flags.error = true;
            Ground.Log.Error("Failed converting string to double");
        }

        return CONTINUE;
    }
    STOD: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[1]);
        GroundBytecodeValue* in = HEAP_GET(heap, instruction->args.at[0]);

        char* status = NULL;

        *final = Ground.New.BytecodeValue(Ground.New.Value.Double(strtod(in->as.String.cstr, &status)));

        if (status != in->as.String.cstr) {
            Ground.Flags.error = true;
            Ground.Log.Error("Failed converting string to double");
        }

        return CONTINUE;
    }
    ITOC: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[1]);
        GroundBytecodeValue* in = HEAP_GET(heap, instruction->args.at[0]);
        
        *final = Ground.New.BytecodeValue(Ground.New.Value.Char((char)in->as.Int));

        return CONTINUE;
    }
    CTOI: {
        GroundBytecodeValue* final = HEAP_GET(heap, instruction->args.at[1]);
        GroundBytecodeValue* in = HEAP_GET(heap, instruction->args.at[0]);
        
        *final = Ground.New.BytecodeValue(Ground.New.Value.Int((int64_t)in->as.Char));

        return CONTINUE;
    }
    TOSTRING: {
        GroundBytecodeValue* in = HEAP_GET(heap, instruction->args.at[0]);

        char buf[4096];

        switch (in->type.type) {
            case GroundType_Int: {
                snprintf(buf, sizeof(buf), "%" PRId64, in->as.Int);
                break;
            }
            case GroundType_Double: {
                snprintf(buf, sizeof(buf), "%f", in->as.Double);
                break;
            }
            case GroundType_Char: {
                snprintf(buf, sizeof(buf), "%c", in->as.Char);
                break;
            }
            case GroundType_Bool: {
                snprintf(buf, sizeof(buf), in->as.Bool ? "true" : "false");
                break;
            }
            case GroundType_String: {
                return CONTINUE;
            }

            default: {
                // TODO: implement tostring for complex types
                snprintf(buf, sizeof(buf), "<FIXME>");
                break;
            }
        }

        *in = Ground.New.BytecodeValue(Ground.New.Value.String(Ground.New.String(buf)));
        
        return CONTINUE;
    }
    FUN: {
        // make a copy of the current state and attach it to the function
        GroundBytecodeFunction* function = &HEAP_GET(heap, instruction->args.at[0])->as.Function;

        if (function->closure == NULL) {
            function->closure = malloc(sizeof(GroundBytecodeHeap));
            if (function->closure == NULL) {
                Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
                Ground.Flags.error = true;
                return CONTINUE;
            }
        } else {
            for (GroundSize i = 0; i < function->closure->len; i++) {
                Ground.Free.BytecodeValue(&function->closure->heap[i]);
            }
            free(function->closure->heap);
        }

        function->closure->capacity = heap->capacity;
        function->closure->len = heap->len;
        function->closure->heap = malloc(sizeof(GroundBytecodeValue) * heap->capacity);

        if (function->closure->heap == NULL) {
            Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
            Ground.Flags.error = true;
            return CONTINUE;
        }

        for (GroundSize i = 0; i < heap->len; i++) {
            function->closure->heap[i] = Ground.Copy.BytecodeValue(&heap->heap[i]);
        }

        return CONTINUE;
    }
    RETURN: {
        return RETURN( *HEAP_GET(heap, instruction->args.at[0]) );
    }
    ENDFUN: {
        // no-op
        return CONTINUE;
    }
    CALL: {
        // call !function $value... &returnIdx
        GroundBytecodeFunction* function = &HEAP_GET(heap, instruction->args.at[0])->as.Function;

        if (function->isNativeFunction) {

            // Ensure we have the right amount and types of arguments first
            if (function->args.count != instruction->args.len - 2) {
                Ground.Log.Error("incorrect amount of arguments for native function in Ground.Bytecode.Instruction.execute");
                Ground.Flags.error = true;
                return CONTINUE;
            }

            ffi_type* argTypes[function->args.count];
            void* args[function->args.count];

            for (GroundSize i = 0; i < function->args.count; i++) {
                if (function->args.at[i].as.type.type != HEAP_GET(heap, instruction->args.at[i+1])->type.type) {
                    printf("%d != %d\n", function->args.at[i].as.type.type, HEAP_GET(heap, instruction->args.at[i+1])->type.type);
                    Ground.Log.Error("incorrect type of argument for native function in Ground.Bytecode.Instruction.execute");
                    Ground.Flags.error = true;
                    return CONTINUE;
                }
                argTypes[i] = ffiTypeFromGroundType(&function->args.at[i].as.type);
                switch (HEAP_GET(heap, instruction->args.at[i+1])->type.type) {
                    case GroundType_Int: {
                        args[i] = &HEAP_GET(heap, instruction->args.at[i+1])->as.Int;
                        break;
                    }
                    case GroundType_Double: {
                        args[i] = &HEAP_GET(heap, instruction->args.at[i+1])->as.Double;
                        break;
                    }
                    case GroundType_Char: {
                        args[i] = &HEAP_GET(heap, instruction->args.at[i+1])->as.Char;
                        break;
                    }
                    case GroundType_Bool: {
                        args[i] = &HEAP_GET(heap, instruction->args.at[i+1])->as.Bool;
                        break;
                    }
                    case GroundType_String: {
                        args[i] = &HEAP_GET(heap, instruction->args.at[i+1])->as.String.cstr;
                        break;
                    }
                    default: {
                        // FIXME implement non-basic types
                        args[i] = HEAP_GET(heap, instruction->args.at[i+1]);
                        break;
                    }
                }
            }

            ffi_cif cif;
            ffi_status status = ffi_prep_cif(
                &cif, FFI_DEFAULT_ABI, function->args.count, ffiTypeFromGroundType(function->returnType), argTypes
            );

            if (status != FFI_OK) {
                Ground.Log.Error("ffi CIF preperation failed in Ground.Bytecode.Instruction.execute");
                Ground.Flags.error = true;
                return CONTINUE;
            }

            union {
                GroundInt    Int;
                GroundDouble Double;
                GroundChar   Char;
                GroundBool   Bool;
                char*        String;
                // TODO more stuff
            } result;

            ffi_call(&cif, function->program.native, &result, args);

            // Put return value into the scope
            switch (function->returnType->type) {
                case GroundType_Int: {
                    HEAP_SET(heap, instruction->args.at[instruction->args.len - 1], Ground.New.BytecodeValue(Ground.New.Value.Int(result.Int)));
                    break;
                }
                case GroundType_Char: {
                    HEAP_SET(heap, instruction->args.at[instruction->args.len - 1], Ground.New.BytecodeValue(Ground.New.Value.Char(result.Char)));
                    break;
                }
                case GroundType_Double: {
                    HEAP_SET(heap, instruction->args.at[instruction->args.len - 1], Ground.New.BytecodeValue(Ground.New.Value.Double(result.Double)));
                    break;
                }
                case GroundType_Bool: {
                    HEAP_SET(heap, instruction->args.at[instruction->args.len - 1], Ground.New.BytecodeValue(Ground.New.Value.Bool(result.Bool)));
                    break;
                }
                case GroundType_String: {
                    HEAP_SET(heap, instruction->args.at[instruction->args.len - 1], Ground.New.BytecodeValue(Ground.New.Value.String(Ground.New.String(result.String))));
                    break;
                }
                default: break; // TODO more types
            }

            return CONTINUE;
        }

        if (function->closure == NULL) {
            Ground.Log.Error("unexpected NULL closure in Ground.Bytecode.Instruction.execute");
            Ground.Flags.error = true;
            return CONTINUE;
        } 

        // amount of captured variables + amount of function args
        GroundSize heapSize = function->closure->len + function->args.count;

        GroundBytecodeHeap newHeap = { malloc(sizeof(GroundBytecodeValue) * heapSize), heapSize, heapSize };
        if (newHeap.heap == NULL) {
            Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
            Ground.Flags.error = true;
            return CONTINUE;
        }

        // load function arguments into the heap
        for (GroundSize i = 0; i < function->args.count; i++) {
            newHeap.heap[i] = Ground.Copy.BytecodeValue(HEAP_GET(heap, instruction->args.at[i + 1]));
        }

        // function arguments are the first indexes, copy closure after
        for (GroundSize i = function->args.count; i < newHeap.len; i++) {
            newHeap.heap[i] = Ground.Copy.BytecodeValue(&function->closure->heap[i - function->args.count]);
        }

        // Now we run the thingy
        GroundBytecodeValue result = Ground.Bytecode.Program.execute(function->program.ground, &newHeap);

        // Deep copy the result before freeing the function's heap
        GroundBytecodeValue resultCopy = Ground.Copy.BytecodeValue(&result);

        // Clean up the new heap 
        for (GroundSize i = 0; i < newHeap.len; i++) {
            Ground.Free.BytecodeValue(&newHeap.heap[i]);
        }
        free(newHeap.heap);

        // And store the result 
        HEAP_SET(heap, instruction->args.at[instruction->args.len - 1], resultCopy);

        return CONTINUE;
    }
    CALLMETHOD: {
        return CONTINUE;
    }
    STRUCT: {
        GroundBytecodeStruct* gbs = &HEAP_GET(heap, instruction->args.at[0])->as.Struct;
        // struct &structName &field OP $value &field OP $value &field OP $value...
        // where:
        //      &field is the field to initialise
        //      OP is a numeric identifier:
        //          0 -> none
        //          1 -> init 
        //          2 -> set
        //          3 -> attach closure to function
        //      $value is either a type reference (OP=0), a value reference (OP=1), or none (OP=2)
        for (GroundSize i = 1; i < instruction->args.len; i++) {
            GroundSize offset = instruction->args.at[i];
            i++;
            GroundSize op = instruction->args.at[i];
            switch (op) {
                case 0: break;
                case 1: {
                    i++;
                    GroundBytecodeValue* type = HEAP_GET(heap, instruction->args.at[i]);
                    switch (type->type.type) {
                        case GroundType_Struct: {
                            // TODO nested structs
                            break;
                        }
                        case GroundType_CoreType: {
                            switch (type->as.CoreType) {
                                case GroundType_Int: {
                                    gbs->values[offset] = Ground.New.BytecodeValue(Ground.New.Value.Int(0));
                                    break;
                                }
                                case GroundType_Double: {
                                    gbs->values[offset] = Ground.New.BytecodeValue(Ground.New.Value.Double(0.0));
                                    break;
                                }
                                case GroundType_String: {
                                    gbs->values[offset] = Ground.New.BytecodeValue(Ground.New.Value.String(Ground.New.String("")));
                                    break;
                                }
                                case GroundType_Char: {
                                    gbs->values[offset] = Ground.New.BytecodeValue(Ground.New.Value.Char(0));
                                    break;
                                }
                                case GroundType_Bool: {
                                    gbs->values[offset] = Ground.New.BytecodeValue(Ground.New.Value.Bool(false));
                                    break;
                                }
                                default: break; // TODO implement all the other stuff
                            }
                        }
                    }
                    break;
                }
                case 2: {
                    i++;
                    gbs->values[offset] = Ground.Copy.BytecodeValue(HEAP_GET(heap, instruction->args.at[i]));
                    break;
                }
                case 3: {
                    GroundBytecodeFunction* function = &gbs->values[offset].as.Function;
                    if (function->closure == NULL) {
                        function->closure = malloc(sizeof(GroundBytecodeHeap));
                        if (function->closure == NULL) {
                            Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
                            Ground.Flags.error = true;
                            return CONTINUE;
                        }
                    } else {
                        for (GroundSize i = 0; i < function->closure->len; i++) {
                            Ground.Free.BytecodeValue(&function->closure->heap[i]);
                        }
                        free(function->closure->heap);
                    }

                    function->closure->capacity = heap->capacity;
                    function->closure->len = heap->len;
                    function->closure->heap = malloc(sizeof(GroundBytecodeValue) * heap->capacity);

                    if (function->closure->heap == NULL) {
                        Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
                        Ground.Flags.error = true;
                        return CONTINUE;
                    }

                    for (GroundSize i = 0; i < heap->len; i++) {
                        function->closure->heap[i] = Ground.Copy.BytecodeValue(&heap->heap[i]);
                    }

                    break;
                }
            }
        }
        return CONTINUE;
    }
    ENDSTRUCT: {
        // no-op
        return CONTINUE;
    }
    INIT: {
        GroundBytecodeValue* type = HEAP_GET(heap, instruction->args.at[1]);
        switch (type->type.type) {
            case GroundType_Struct: {
                // copy the contents of the struct into the object 
                GroundBytecodeObject object = {
                    .size = type->as.Struct.size,
                    .capacity = type->as.Struct.size,
                    .values = malloc(sizeof(GroundBytecodeValue) * type->as.Struct.size)
                };
                for (GroundSize i = 0; i < type->as.Struct.size; i++) {
                    object.values[i] = Ground.Copy.BytecodeValue(&type->as.Struct.values[i]);
                }
                HEAP_SET(heap, instruction->args.at[0], ((GroundBytecodeValue) {.as.Object = object, .type = {GroundType_Object}}));
                break;
            }
            case GroundType_CoreType: {
                switch (type->as.CoreType) {
                    case GroundType_Int: {
                        HEAP_SET(heap, instruction->args.at[0], Ground.New.BytecodeValue(Ground.New.Value.Int(0)));
                        break;
                    }
                    case GroundType_Double: {
                        HEAP_SET(heap, instruction->args.at[0], Ground.New.BytecodeValue(Ground.New.Value.Double(0.0)));
                        break;
                    }
                    case GroundType_String: {
                        HEAP_SET(heap, instruction->args.at[0], Ground.New.BytecodeValue(Ground.New.Value.String(Ground.New.String(""))));
                        break;
                    }
                    case GroundType_Char: {
                        HEAP_SET(heap, instruction->args.at[0], Ground.New.BytecodeValue(Ground.New.Value.Char(0)));
                        break;
                    }
                    case GroundType_Bool: {
                        HEAP_SET(heap, instruction->args.at[0], Ground.New.BytecodeValue(Ground.New.Value.Bool(false)));
                        break;
                    }
                    default: break; // TODO implement all the other stuff
                }
            }
            default: break; // should not be reached
        }
        return CONTINUE;
    }
    GETFIELD: {
        // args: [parent_offset, field0_offset, ..., fieldF_offset, output_offset]
        GroundBytecodeValue* current = HEAP_GET(heap, instruction->args.at[0]);

        for (GroundSize i = 1; i < instruction->args.len - 1; i++) {
            current = &current->as.Object.values[instruction->args.at[i]];
        }

        GroundBytecodeValue* output = HEAP_GET(heap, instruction->args.at[instruction->args.len - 1]);
        Ground.Free.BytecodeValue(output);
        *output = Ground.Copy.BytecodeValue(current);

        return CONTINUE;
    }
    SETFIELD: {
        return CONTINUE;
    }
    USE: {
        return CONTINUE;
    }
    EXTERN: {
        // extern "libfile.so" "symbolName" !fnName -returnType -argType...
        void* handle = Ground.FFI.openSharedObject(HEAP_GET(heap, instruction->args.at[0])->as.String.cstr);
        if (Ground.Flags.error) {
            return CONTINUE;
        }
        void* function = Ground.FFI.getFunction(handle, HEAP_GET(heap, instruction->args.at[1])->as.String.cstr);
        if (Ground.Flags.error) {
            return CONTINUE;
        }
        GroundSize argsSize = instruction->args.len - 4; // subtract 4 for libfile, symbol name, fn name, return type
        GroundBytecodeFunction bf = {
            .isNativeFunction = true,
            .closure = NULL,
            .program.native = function,
            .args = {
                .at = malloc(sizeof(GroundFunctionArg) * argsSize),
                .capacity = argsSize,
                .count = argsSize
            },
            .returnType = malloc(sizeof(GroundType))
        };
        if (bf.args.at == NULL || bf.returnType == NULL) {
            Ground.Log.Error("malloc failed in Ground.Bytecode.Instruction.execute");
            Ground.Flags.error = true;
            return CONTINUE;
        }

        enum GroundTypeType returnTypeType = HEAP_GET(heap, instruction->args.at[3])->type.type;

        switch (returnTypeType) {
            case GroundType_Struct: {
                bf.returnType->type = GroundType_Object;
                // TODO implement structs
                break;
            }
            case GroundType_CoreType: {
                bf.returnType->type = HEAP_GET(heap, instruction->args.at[3])->as.CoreType;
                break;
            }
            default: {
                // should have been caught elsewhere, not really our problem
                break;
            }
        }

        for (size_t i = 0; i < argsSize; i++) {
            GroundBytecodeValue* argTypeVal = HEAP_GET(heap, instruction->args.at[i + 4]);
            switch (argTypeVal->type.type) {
                case GroundType_Struct: {
                    bf.args.at[i].as.type.type = GroundType_Object;
                    // TODO implement structs
                    break;
                }
                case GroundType_CoreType: {
                    bf.args.at[i].as.type.type = argTypeVal->as.CoreType;
                    break;
                }
                default: {
                    // should have been caught elsewhere, not really our problem
                    break;
                }
            }
        }

        GroundBytecodeValue val = {
            .type = {GroundType_Function},
            .as.Function = bf
        };

        HEAP_SET(heap, instruction->args.at[2], val);

        return CONTINUE;
    }
    CREATELABEL: {
        // no-op
        return CONTINUE;
    }
    PAUSE: {
        return CONTINUE;
    }
    DROP: {
        GroundBytecodeValue* in = HEAP_GET(heap, instruction->args.at[0]);
        Ground.Free.BytecodeValue(in);
        *in = Ground.New.BytecodeValue(Ground.New.Value.Int(0));
        return CONTINUE;
    }
    LICENSE: {
        return CONTINUE;
    }
    ERRORCMD: {
        return CONTINUE;
    }
    THROW: {
        return CONTINUE;
    }
    CATCH: {
        return CONTINUE;
    }

    Ground.Log.Error("operation fell through in Ground.Instruction.execute()");
    Ground.Flags.error = true;

    return CONTINUE;
}