#include "lisp.h"

Node *lisp_function_addition(Nodes *args, Scopes *scopes) {
    UNUSED(scopes);

    if (args->count != 2) {
        printf("'+' expects two arguments!\n");
        return NULL;
    }

    if (args->items[0].kind != NODE_KIND_NUMBER ||
        args->items[1].kind != NODE_KIND_NUMBER) {
        printf("'+' can only add numbers, you specified something else!\n");
        return NULL;
    }

    Node *node = malloc(sizeof(Node));
    node->kind = NODE_KIND_NUMBER;

    intptr_t a = args->items[0].as_number;
    intptr_t b = args->items[1].as_number;
    node->as_number = a + b;
    return node;
}

Node *lisp_function_println(Nodes *args, Scopes *scopes) {
    if (args->count != 1) {
        printf("'+' expects one argument!\n");
        return NULL;
    }

    Node *result = eval(&args->items[0], scopes);
    node_print(*result);
    printf("\n");

    return result;
}

Node *lisp_function_list(Nodes *args, Scopes *scopes) {
    UNUSED(scopes);

    Node *node = malloc(sizeof(Node));
    node->kind = NODE_KIND_LIST;
    node->as_list = args;
    return node;
}

Node *lisp_function_append(Nodes *args, Scopes *scopes) {
    UNUSED(scopes);

    if (args->count != 2) {
        printf("'append' expects two arguments!\n");
        return NULL;
    }

    Node *node = malloc(sizeof(Node));
    node->kind = NODE_KIND_LIST;

    if (args->items[0].kind != NODE_KIND_LIST ||
        args->items[1].kind != NODE_KIND_LIST) {
        printf("'append' can only append two lists!\n");
        return NULL;
    }

    Nodes *nodes = malloc(sizeof(Nodes));

    Nodes *a = args->items[0].as_list;
    nob_da_append_many(nodes, a->items, a->count);

    Nodes *b = args->items[1].as_list;
    nob_da_append_many(nodes, b->items, b->count);

    node->as_list = nodes;
    return node;
}

Node *lisp_function_length(Nodes *args, Scopes *scopes) {
    UNUSED(scopes);

    if (args->count != 1) {
        printf("'length' expects one argument!\n");
        return NULL;
    }

    if (args->items[0].kind != NODE_KIND_LIST) {
        printf("'length' can only be used on lists!\n");
        return NULL;
    }

    Node *node = malloc(sizeof(Node));
    node->kind = NODE_KIND_NUMBER;
    node->as_number = args->items[0].as_list->count;
    return node;
}

Node *lisp_function_isnull(Nodes *args, Scopes *scopes) {
    UNUSED(scopes);

    if (args->count != 1) {
        printf("'null?' expects one argument!\n");
        return NULL;
    }

    if (args->items[0].kind != NODE_KIND_LIST) {
        printf("'null?' can only be used on lists!\n");
        return NULL;
    }

    Node *node = malloc(sizeof(Node));
    node->kind = NODE_KIND_NUMBER;
    node->as_number = args->items[0].as_list->count == 0 ? 1 : 0;
    return node;
}