#include <assert.h>
#include <stddef.h>

#include "uclisp.h"
#include "internal.h"
#include "utility.h"
#include "state.h"

// TODO: remove string.h
#include <string.h>

struct ucl_object *ucl_evaluate_builtin_form(struct ucl_state *state, struct ucl_object *list) {
    // TODO: Recursively eval args
    struct ucl_object *evaluated_list = ucl_nil_create();

    FOREACH_LIST(list, iter, item) {
        struct ucl_object *obj = ucl_evaluate(state, item);
        ucl_list_append(evaluated_list, obj);
    };

    struct ucl_object *fun = ucl_car(evaluated_list);
    struct ucl_object *args = ucl_cdr(evaluated_list);
    struct ucl_object *result = NULL;

    assert(fun->type == UCL_TYPE_BUILTIN);
    if (fun->type == UCL_TYPE_BUILTIN) {
        result = fun->builtin(state, args);
    }

    // TODO: cleanup

    return result;
}

struct ucl_object *ucl_evaluate_special_form(struct ucl_state *state, struct ucl_object *list) {
    // TODO: Recursively eval args
    const char *fun_sym = ucl_car(list)->symbol;

    struct ucl_object *fun = ucl_state_get(state, ucl_car(list)->symbol);
    struct ucl_object *args = ucl_cdr(list);
    struct ucl_object *result = NULL;

    result = fun->special(state, args);

    return result;
}



struct ucl_object *ucl_evaluate_list(struct ucl_state *state, struct ucl_object *list) {
    if (list->cell.car == NULL) {
        return list;
    }

    struct ucl_object *fun_sym = ucl_car(list);
    if (fun_sym->type != UCL_TYPE_SYMBOL) {
        return ucl_error_create("Unknown function symbol");
    }
    struct ucl_object *fun = ucl_state_get(state, fun_sym->symbol);
    UCL_RET_IF_ERROR(fun);

    if (fun->type == UCL_TYPE_SPECIAL) {
        return ucl_evaluate_special_form(state, list);
    } else if (fun->type == UCL_TYPE_BUILTIN) {
        return ucl_evaluate_builtin_form(state, list);
    } else {
        assert(0);
        // TODO: Lisp functions and other errors
    }
}

struct ucl_object *ucl_evaluate(struct ucl_state *state, struct ucl_object *obj) {
    assert(obj != NULL);

    switch (obj->type) {
        case UCL_TYPE_CELL:
            return ucl_evaluate_list(state, obj);
        case UCL_TYPE_SYMBOL:
            return ucl_state_get(state, obj->symbol);
        case UCL_TYPE_INT:
        case UCL_TYPE_STRING:
        case UCL_TYPE_ERROR:
            return obj;
        case UCL_TYPE_BUILTIN:
        case UCL_TYPE_SPECIAL:
        case UCL_TYPE_COUNT:
            assert(0);
            return NULL;
    }
}