#include "parser.h"
#include "log.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

Module* parser_parse(TokenStream* ts) {
	Token t = tokenstream_next(ts);
	if (t.token != TOKEN_MODULE) {
		log_on_line(&t.location, t.location.column_end, "expected 'module' keyword");
		return NULL;
	}

	t = tokenstream_next(ts);
	if (t.token != TOKEN_IDENTIFIER) {
		log_on_line(&t.location, t.location.column_end, "expected module name");
		return NULL;
	}

	Module* module = (Module*)malloc(sizeof(Module));
	if (module == NULL) {
		fprintf(stderr, "Out of memory\n");
		exit(1);
	}
	module->name = NULL;
	module->imports = NULL;
	module->import_count = 0;

	module->name = (char*)malloc(t.text.length + 1);
	if (module->name == NULL) {
		fprintf(stderr, "Out of memory\n");
		exit(1);
	}

	memcpy(module->name, t.text.data, t.text.length);
	module->name[t.text.length] = '\0';

	t = tokenstream_next(ts);
	if (t.token != TOKEN_SEMICOLON) {
		log_on_line(&t.location, t.location.column_end, "expected ';' after module name");
		parser_free(module);
		return NULL;
	}

	module->imports = NULL;
	module->import_count = 0;

	while (1) {
		t = tokenstream_next(ts);
		if (t.token != TOKEN_IMPORT) {
			break;
		}

		ImportDeclaration* new_imports = realloc(module->imports, (module->import_count + 1) * sizeof(ImportDeclaration));
		if (!new_imports) {
			fprintf(stderr, "Out of memory\n");
			exit(1);
		}
		module->imports = new_imports;

		t = tokenstream_next(ts);
		bool is_public = false;
		if (t.token == TOKEN_IDENTIFIER && strncmp(t.text.data, "public", t.text.length) == 0) {
			is_public = true;
			t = tokenstream_next(ts);
		}

		if (t.token != TOKEN_IDENTIFIER) {
			log_on_line(&t.location, t.location.column_end, "expected module name to import");
			parser_free(module);
			return NULL;
		}

		module->imports[module->import_count].module_name = (char*)malloc(t.text.length + 1);
		if (!module->imports[module->import_count].module_name) {
			fprintf(stderr, "Out of memory\n");
			exit(1);
		}
		memcpy(module->imports[module->import_count].module_name, t.text.data, t.text.length);
		module->imports[module->import_count].module_name[t.text.length] = '\0';
		module->imports[module->import_count].is_public = is_public;
		module->import_count++;

		t = tokenstream_next(ts);
		if (t.token != TOKEN_SEMICOLON) {
			log_on_line(&t.location, t.location.column_end, "expected ';' after import");
			parser_free(module);
			return NULL;
		}
	}

	return module;
}

void parser_free(Module* module) {
	if (module == NULL) return;
	if (module->imports != NULL) {
		for (size_t i = 0; i < module->import_count; i++) {
			free(module->imports[i].module_name);
		}
		free(module->imports);
	}
	free(module->name);
	free(module);
}