/* SPDX-License-Identifier: copyleft-next-0.3.1 */
/* Copyright 2024 Kim Kuparinen < kimi.h.kuparinen@gmail.com > */

/** @file scope.c
 *
 * Implementations for scope handling stuff.
 */

#include <stddef.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <assert.h>

#include <fwd/debug.h>
#include <fwd/scope.h>

struct scope *create_scope()
{
	/* if I ever try making the parser multithreaded, this should be atomic. */
	static size_t counter = 0;

	struct scope *scope = calloc(1, sizeof(struct scope));
	if (!scope) {
		internal_error("ran out of memory allocating scope");
		return NULL;
	}

	scope->number = counter++;
	scope->symbols = visible_create(16); /* arbitrary number */
	scope->traits = visible_create(1);
	scope->types = visible_create(1);
	return scope;
}

void destroy_scope(struct scope *scope)
{
	if (!scope)
		return;

	if (!scope->parent) {
		free((void *)scope->fctx.fbuf);
		free((void *)scope->fctx.fname);
	}

	visible_destroy(&scope->symbols);
	visible_destroy(&scope->traits);
	visible_destroy(&scope->types);

	struct scope *prev = scope->children, *cur;
	if (prev)
		do {
			cur = prev->next;
			destroy_scope(prev);
		} while ((prev = cur));

	free(scope);
}

int scope_add_symbol(struct scope *scope, struct ast *symbol)
{
	assert(symbol->k == AST_VAR_DEF || symbol->k == AST_PROC_DEF);
	struct ast **exists = visible_insert(&scope->symbols, symbol->s, symbol);
	if (!exists) {
		internal_error("failed inserting symbol into scope");
		return -1;
	}

	if (*exists != symbol) {
		semantic_error(scope, symbol, "symbol redefined");
		semantic_info(scope, *exists, "previously here");
		return -1;
	}

	return 0;
}

struct ast *scope_find_symbol(struct scope *scope, char *id)
{
	struct ast **v = visible_find(&scope->symbols, id);
	if (!v)
		return NULL;

	return *v;
}

struct ast *file_scope_find_symbol(struct scope *scope, char *id)
{
	if (!scope)
		return NULL;

	struct ast *found = scope_find_symbol(scope, id);
	if (found)
		return found;

	return file_scope_find_symbol(scope->parent, id);
}

int scope_add_type(struct scope *scope, struct ast *type)
{
	assert(type->k == AST_STRUCT_DEF);
	struct ast **exists = visible_insert(&scope->symbols, type->s, type);
	if (!exists) {
		internal_error("failed inserting type into scope");
		return -1;
	}

	if (*exists != type) {
		semantic_error(scope, type, "type redefined");
		semantic_info(scope, *exists, "previously here");
		return -1;
	}

	return 0;
}

int scope_add_chain(struct scope *scope, struct ast *type)
{
	assert(type->k == AST_STRUCT_CONT);
	struct ast *exists = file_scope_find_type(scope, type->s);
	if (!exists) {
		semantic_error(scope, type, "no previous definition");
		return -1;
	}

	assert(exists->k == AST_STRUCT_DEF || exists->k == AST_STRUCT_CONT);
	if (ast_flags(exists, AST_FLAG_PUBLIC) || !ast_flags(type, AST_FLAG_PUBLIC)) {
		type->chain = exists;
		struct ast **v = visible_insert(&scope->types, type->s, type);
		if (!v) {
			internal_error("failed inserting type into chain");
			return -1;
		}

		/* overwrite root */
		if (*v != type)
			*v = type;

		return 0;
	}

	struct ast *next = exists->chain;
	while (next->k == AST_STRUCT_CONT && !ast_flags(next, AST_FLAG_PUBLIC)) {
		exists = next;
		next = next->chain;
	}

	exists->chain = type;
	type->chain = exists;
	return 0;
}

struct ast *scope_find_type(struct scope *scope, char *id)
{
	struct ast **v = visible_find(&scope->types, id);
	if (!v)
		return NULL;

	return *v;
}

struct ast *file_scope_find_type(struct scope *scope, char *id)
{
	if (!scope)
		return NULL;

	struct ast *found = scope_find_type(scope, id);
	if (found)
		return found;

	return file_scope_find_type(scope->parent, id);
}

int scope_add_trait(struct scope *scope, struct ast *trait)
{
	assert(trait->k == AST_TRAIT_DEF);
	struct ast **exists = visible_insert(&scope->symbols, trait->s, trait);
	if (!exists) {
		internal_error("failed inserting trait into scope");
		return -1;
	}

	if (*exists != trait) {
		semantic_error(scope, trait, "trait redefined");
		semantic_info(scope, *exists, "previously here");
		return -1;
	}

	return 0;
}
struct ast *scope_find_trait(struct scope *scope, char *id)
{
	struct ast **v = visible_find(&scope->traits, id);
	if (!v)
		return NULL;

	return *v;
}

struct ast *file_scope_find_trait(struct scope *scope, char *id)
{
	if (!scope)
		return NULL;

	struct ast *found = scope_find_trait(scope, id);
	if (found)
		return found;

	return file_scope_find_trait(scope->parent, id);
}

void scope_add_scope(struct scope *parent, struct scope *child)
{
	assert(parent);
	assert(child);

	child->fctx = parent->fctx;
	child->parent = parent;
	child->next = parent->children;
	parent->children = child;
}