#include "ast.h"
#include <stdlib.h>

static void expr_destroy(struct expr_node* node);
static void stmt_destroy(struct stmt_node* node);

static void var_decl_destroy(struct var_decl_node* node) {
    free(node->ident);
}

static void var_ref_destroy(struct var_ref_node* node) {
    free(node->ident);
}

static void lval_destroy(struct lval_node* node) {
    switch (node->type) {
        case LVAL_VAR_DECL:
            var_decl_destroy(&node->as._var_decl);
            break;
        case LVAL_VAR_REF:
            var_ref_destroy(&node->as._var_ref);
            break;
    }
}

static void assign_destroy(struct assign_node* node) {
    lval_destroy(&node->lval);
    expr_destroy(node->rval);
    free(node->rval);
}

static void group_destroy(struct group_node* node) {
    struct stmt_node* body_node = node->body_head;
    while (body_node != NULL) {
        struct stmt_node* next = body_node->next;
        stmt_destroy(body_node);
        free(body_node);
        body_node = next;
    }
}

static void fn_decl_destroy(struct fn_decl_node* node) {
    free(node->name);

    struct var_decl_node* args_node = node->args_head;
    while (args_node != NULL) {
        struct var_decl_node* next = args_node->next;
        var_decl_destroy(args_node);
        free(args_node);
        args_node = next;
    }

    group_destroy(&node->body);
}

static void return_destroy(struct return_node* node) {
    if (node->ret_val != NULL) {
        expr_destroy(node->ret_val);
        free(node->ret_val);
    }
}

static void str_lit_destroy(struct str_lit_node* node) {
    free(node->val);
}

static void call_destroy(struct call_node* node) {
    /* don't destroy node->called_fn, this is owned by its declaration */
    struct expr_node* args_node = node->args_head;
    while (args_node != NULL) {
        struct expr_node* next = args_node->next;
        expr_destroy(args_node);
        free(args_node);
        args_node = next;
    }
}

static void expr_destroy(struct expr_node* node) {
    switch (node->type) {
        case EXPR_INT_LIT:
        case EXPR_FLOAT_LIT:
        case EXPR_CHAR_LIT:
            break;
        case EXPR_STR_LIT:
            str_lit_destroy(&node->as._str_lit);
            break;
        case EXPR_VAR_REF:
            var_ref_destroy(&node->as._var_ref);
            break;
        case EXPR_ASSIGN:
            assign_destroy(&node->as._assign);
            break;
        case EXPR_CALL:
            call_destroy(&node->as._call);
            break;
    }
}

static void stmt_destroy(struct stmt_node* node) {
    switch (node->type) {
        case STMT_EMPTY:
            break;
        case STMT_EXPR:
            expr_destroy(&node->as._expr);
            break;
        case STMT_VAR_DECL:
            var_decl_destroy(&node->as._var_decl);
            break;
        case STMT_RETURN:
            return_destroy(&node->as._return);
            break;
        case STMT_GROUP:
            group_destroy(&node->as._group);
    }
}

static void root_node_destroy(struct root_node* node) {
    switch (node->type) {
        case ROOT_FN_DECL:
            fn_decl_destroy(&node->as._fn_decl);
            break;
    }
}

void ast_destroy(struct root_node* head) {
    struct root_node* node = head;
    while (node != NULL) {
        struct root_node* next = node->next;
        root_node_destroy(node);
        free(node);
        node = next;
    }
}