#include "../../Headers/Sagittarius.h"
#include "../../Headers/SagittariusInternal.h"
#include <stdlib.h>
#include <string.h>

SAGITTARIUS_API SagittariusVM* sagittarius_vm_new(uint64_t memory_size){
    SagittariusVM* vm = malloc(sizeof(SagittariusVM));
    if (!vm) return NULL;
    
    vm->Memory.data = malloc(memory_size);
    vm->Memory.size = memory_size;
    
    // Clear registers
    memset(vm->core.reg.head, 0, sizeof(vm->core.reg.head));
    
    // Link core
    vm->core.memory = &vm->Memory;
    vm->core.vm = vm;
    vm->core.pc = 0;
    
    // Initialize syscalls
    vm->SagittariusSyscallEntries = NULL;
    vm->SagittariusSyscallCount = 0;
    vm->SagittariusSyscallCapacity = 0;
    
    vm->panic_handler = NULL;
    
    return vm;
}

SAGITTARIUS_API void sagittarius_vm_free(SagittariusVM* vm){
    if (vm) {
        if (vm->Memory.data) free(vm->Memory.data);
        if (vm->SagittariusSyscallEntries) free(vm->SagittariusSyscallEntries);
        free(vm);
    }
}

SAGITTARIUS_API void sagittarius_register_syscall(SagittariusVM *vm, uint64_t id, SagittariusSyscall syscall) {
    if (!vm) return;
    if (vm->SagittariusSyscallCount >= vm->SagittariusSyscallCapacity) {
        vm->SagittariusSyscallCapacity = vm->SagittariusSyscallCapacity == 0 ? 4 : vm->SagittariusSyscallCapacity * 2;
        vm->SagittariusSyscallEntries = realloc(vm->SagittariusSyscallEntries, vm->SagittariusSyscallCapacity * sizeof(SagittariusSyscallEntry));
    }
    vm->SagittariusSyscallEntries[vm->SagittariusSyscallCount].id = id;
    vm->SagittariusSyscallEntries[vm->SagittariusSyscallCount].syscall = syscall;
    vm->SagittariusSyscallCount++;
}

SAGITTARIUS_API void sagittarius_mem_resize(SagittariusVM* vm, uint64_t new_size){
    if (vm) {
        vm->Memory.data = realloc(vm->Memory.data, new_size);
        vm->Memory.size = new_size;
    }
}

SAGITTARIUS_API uint64_t sagittarius_mem_getsize(SagittariusVM* vm){
    return vm ? vm->Memory.size : 0;
}

SAGITTARIUS_API void sagittarius_load_program_to_mem(SagittariusVM *vm, SagittariusProgram *program, uint64_t offset) {
    if (!vm || !program) return;
    
    uint64_t required_size = offset + program->instCount * 8 + program->data_size;
    if (required_size > vm->Memory.size) {
        sagittarius_mem_resize(vm, required_size);
    }
    
    if (program->instCount > 0) {
        memcpy(vm->Memory.data + offset, program->instructions, program->instCount * 8);
    }
    if (program->data_size > 0) {
        memcpy(vm->Memory.data + offset + program->instCount * 8, program->data, program->data_size);
    }
    
    vm->core.pc = offset;
}

SAGITTARIUS_API SagittariusProgram *sagittarius_load_program_from_byte_array(uint8_t *data, uint64_t size) {
    if (size < 28) return NULL;
    if (memcmp(data, SAGITTARUIS_PROGRAM_HEAD, 7) != 0) return NULL;
    
    uint32_t version;
    memcpy(&version, data + 8, 4);
    if (version != SAGITTARIUS_PROGRAM_FORMAT_VERSION) return NULL;
    
    uint64_t instCount;
    memcpy(&instCount, data + 12, 8);
    
    uint64_t data_size;
    memcpy(&data_size, data + 20, 8);
    
    if (size < 28 + instCount * 8 + data_size) return NULL;
    
    SagittariusProgram *prog = malloc(sizeof(SagittariusProgram));
    prog->instCount = instCount;
    if (instCount > 0) {
        prog->instructions = malloc(instCount * sizeof(SagittariusInst));
        memcpy(prog->instructions, data + 28, instCount * 8);
    } else {
        prog->instructions = NULL;
    }
    
    prog->data_size = data_size;
    if (data_size > 0) {
        prog->data = malloc(data_size);
        memcpy(prog->data, data + 28 + instCount * 8, data_size);
    } else {
        prog->data = NULL;
    }
    
    return prog;
}

SAGITTARIUS_API void sagittarius_step(SagittariusVM *vm) {
    if (!vm) return;
    if (vm->core.pc >= vm->Memory.size) {
        if (vm->panic_handler) vm->panic_handler(&vm->core, Sagittarius_Msg_OOB, "PC out of bounds");
        return;
    }
    
    SagittariusInst inst;
    memcpy(&inst, &vm->Memory.data[vm->core.pc], sizeof(SagittariusInst));
    
    uint8_t opcode = inst.data & 0xFF;
    bool success = false;
    
    switch ((SagittariusInstDef)opcode) {
        case math2:    success = Math2Op(&vm->core, inst); break;
        case math1:    success = Math1Op(&vm->core, inst); break;
        case cvt:      success = SagCvt(&vm->core, inst); break;
        case set:      success = SagSet(&vm->core, inst); break;
        case mv:       success = SagMv(&vm->core, inst); break;
        case cp:       success = SagCp(&vm->core, inst); break;
        case save:     success = SagSave(&vm->core, inst); break;
        case load:     success = SagLoad(&vm->core, inst); break;
        case jmp:      success = SagJmp(&vm->core, inst); break;
        case jmp_if:   success = SagJmpIf(&vm->core, inst); break;
        case call:     success = SagCall(&vm->core, inst); break;
        case ret:      success = SagRet(&vm->core, inst); break;
        case cmp:      success = SagCmp(&vm->core, inst); break;
        case mathv:    success = SagMathV(&vm->core, inst); break;
        case halt:     success = SagHalt(&vm->core, inst); break;
        case syscall:  success = SagSyscall(&vm->core, inst); break;
        case tsyscall: success = SagTSyscall(&vm->core, inst); break;
        default: {
            if (vm->panic_handler) vm->panic_handler(&vm->core, Sagittarius_Msg_Unknown, "Unknown opcode");
            break;
        }
    }
    
    (void)success;
}