#include <assert.h>

#include "apfl.h"

#include "alloc.h"
#include "bytecode.h"
#include "gc.h"

struct instruction_list *
apfl_instructions_new(struct gc *gc, int line)
{
    struct instruction_list *ilist = apfl_gc_new_instructions(gc);
    if (ilist == NULL) {
        return NULL;
    }
    *ilist = (struct instruction_list) {
        .instructions = NULL,
        .len = 0,
        .cap = 0,
        .line = line,
    };
    return ilist;
}

void
apfl_instructions_deinit(struct apfl_allocator allocator, struct instruction_list *ilist)
{
    FREE_LIST(allocator, ilist->instructions, ilist->cap);
}

#define GET_ARGUMENT(ilist, i, arg)     \
    do {                                \
        if (i >= ilist->len) {          \
            return;                     \
        }                               \
        arg = ilist->instructions[++i]; \
    } while (0)

void
apfl_gc_instructions_traverse(struct instruction_list *ilist, gc_visitor cb, void *opaque)
{
    union instruction_or_arg arg;

    for (size_t i = 0; i < ilist->len; i++) {
        switch (ilist->instructions[i].instruction) {
        case INSN_NIL:
        case INSN_TRUE:
        case INSN_FALSE:
        case INSN_LIST_APPEND:
        case INSN_LIST_EXPAND_INTO:
        case INSN_DICT:
        case INSN_DICT_APPEND_KVPAIR:
        case INSN_GET_MEMBER:
        case INSN_NEXT_LINE:
            break;
        case INSN_NUMBER:
        case INSN_LIST:
        case INSN_SET_LINE:
            i++;
            break;
        case INSN_STRING:
        case INSN_VAR_GET:
        case INSN_VAR_SET:
        case INSN_VAR_NEW:
            GET_ARGUMENT(ilist, i, arg);
            cb(opaque, GC_OBJECT_FROM(arg.string, GC_TYPE_STRING));
            break;
        }
    }
}

const char *
apfl_instruction_to_string(enum instruction insn)
{
    switch (insn) {
    case INSN_NIL:
        return "INSN_NIL";
    case INSN_TRUE:
        return "INSN_TRUE";
    case INSN_FALSE:
        return "INSN_FALSE";
    case INSN_NUMBER:
        return "INSN_NUMBER";
    case INSN_STRING:
        return "INSN_STRING";
    case INSN_LIST:
        return "INSN_LIST";
    case INSN_LIST_APPEND:
        return "INSN_LIST_APPEND";
    case INSN_LIST_EXPAND_INTO:
        return "INSN_LIST_EXPAND_INTO";
    case INSN_DICT:
        return "INSN_DICT";
    case INSN_DICT_APPEND_KVPAIR:
        return "INSN_DICT_APPEND_KVPAIR";
    case INSN_GET_MEMBER:
        return "INSN_GET_MEMBER";
    case INSN_VAR_GET:
        return "INSN_VAR_GET";
    case INSN_VAR_SET:
        return "INSN_VAR_SET";
    case INSN_VAR_NEW:
        return "INSN_VAR_NEW";
    case INSN_NEXT_LINE:
        return "INSN_NEXT_LINE";
    case INSN_SET_LINE:
        return "INSN_SET_LINE";
    }

    return "??";
}