#include "exec.h"

void exec_init(struct exec* self)
{
    assert(self);
    self->pc = 0;
}

void exec_free(struct exec* self)
{
    assert(self);
}

void exec_prog(struct exec* self,
               struct moka* moka,
               struct prog* prog)
{
    assert(self); assert(moka); assert(prog);
    self->pc = 0;

    while (self->pc < prog->instructions.size)
    {
        exec_instr(self,
                   moka,
                   prog,
                   prog->instructions.data[self->pc]);
    }
}

void exec_instr(struct exec* self,
                struct moka* moka,
                struct prog* prog,
                struct instruction* instr)
{
    assert(self); assert(moka); assert(instr);
    int param = instr->param;

    switch (instr->opcode)
    {
        case OP_CALL: {
            MOKA fun = moka_pop(moka);
            struct vec args;
            vec_init(&args);

            for (ssize_t i=0; i<param; i++)
            {
                MOKA arg = moka_pop(moka);
                vec_push(&args, (void*) arg);
            }

            struct value* val = moka->global_values.data[
                moka_get_ref(moka, fun)
            ];

            assert(val->type == TY_NATIVE);
            struct native* native = val->data.native;
            (native->fun)(moka, &args);

            vec_free(&args);
            self->pc++;
        } break;

        case OP_GLOBAL_LOAD: {
            moka_push_ref(moka, param, 0);
            self->pc++;
        } break;

        case OP_PUSH: {
            struct value* value = prog->values.data[param];
            switch (value->type)
            {
                case TY_INT: {
                    moka_push_int(moka, value->data.integer, value->line);
                } break;

                case TY_FLOAT: {
                    moka_push_float(moka, value->data.real, value->line);
                } break;

                case TY_BOOL: {
                    moka_push_bool(moka, value->data.boolean, value->line);
                } break;

                case TY_STRING: {
                    moka_push_string(moka, value->data.str, value->line);
                } break;

                case TY_SYMBOL: {
                    moka_push_symbol(moka, value->data.sym, value->line);
                } break;

                case TY_LAZY: {
                    moka_push_lazy(moka, value->data.lazy, value->line);
                } break;
                default: {
                    fprintf(stderr,
                        "cannot push value of type <%s>\n",
                        TypeKindStr[value->type]
                    );

                    abort();
                } break;
            }
            self->pc++;
        } break;

        default: {
            fprintf(stderr, "cannot execute opcode <%s>\n",
                    OpcodeKindStr[instr->opcode]);
            abort();
        } break;
    }
}