/*
 *  SPL - The SPL Programming Language
 *  Copyright (C) 2004, 2005  Clifford Wolf <clifford@clifford.at>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  webspl.c: CGI Script for using SPL for web applications
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <assert.h>
#include <unistd.h>
#include <stdarg.h>
#include <errno.h>

#include "spl.h"
#include "webspl_common.h"
#include "compat.h"

static struct spl_vm *vm;
static struct spl_task *task;

static void get_session_lock(const char *basedir, const char *session)
{
	char *lockfile;
	int fd, retries = 0;

	create_dumpdir(basedir);
	expire_dumpdir(basedir, EXPIRE_DUMPDIR_TIMEOUT, EXPIRE_DUMPDIR_INTERVAL);

	my_asprintf(&lockfile, "%s/webspl_cache/%.*s.lock",
		basedir, (int)strcspn(session, ":"), session);

retry_lock:
	fd = open(lockfile, O_CREAT|O_EXCL, 0600);
	if ( fd == -1 && errno == EEXIST ) {
		my_sleep(1);
		if ( retries++ > 10 ) {
			spl_report(SPL_REPORT_HOST, vm, "Stalled lock on session file!\n");
			exit(0);
		}
		goto retry_lock;
	}

	close(fd);
	free(lockfile);
}

static void free_session_lock(const char *basedir, const char *session)
{
	char *lockfile;

	my_asprintf(&lockfile, "%s/webspl_cache/%.*s.lock",
		basedir, (int)strcspn(session, ":"), session);

	unlink(lockfile);
	free(lockfile);
}

int main()
{
	char basedir[1024] = "/tmp";
	char *script_file = getenv("PATH_TRANSLATED");
	char *scriptdir = script_file;
	getcwd(basedir, 1024);

	if (!scriptdir) {
		printf("Content-type: text/plain\n\n");

		printf("Called webspl.cgi directly!\n");
		printf("This script should only be used as action handler!\n\n");

		printf("For debuging, e.g.:\n");
		printf("QUERY_STRING='sid=HVMwQjeajMv3cOtAAP5WEUEP:wsfc_4&switch=3' \\\n");
		printf("PATH_TRANSLATED='cfpmanager/cfpmanager.webspl' ./webspl.cgi\n\n");
		return 1;
	}

	if ( scriptdir ) {
		char *lastslash = strrchr(scriptdir, '/');
		if ( lastslash ) {
			char *new_scriptdir = malloc(lastslash-scriptdir + 1);
			strncpy(new_scriptdir, scriptdir, lastslash-scriptdir);
			new_scriptdir[lastslash-scriptdir] = 0;
			scriptdir = new_scriptdir;
		} else
			scriptdir = basedir;
	} else
		scriptdir = basedir;
	chdir(scriptdir);

	struct cgi_config *cfg = cgi_config_read(script_file);

	printf("Cache-Control: no-cache, must-revalidate, no-store\n");
	printf("Pragma: nocache\n");
	printf("Expires: 0\n");

	SPL_REGISTER_BUILTIN_MODULE(cgi);
	spl_report = spl_mod_cgi_reportfunc;

	vm = spl_vm_create();
	my_asprintf(&vm->path, ".:./spl_modules:%s/spl_modules:%s", basedir, spl_system_modules_dir());
	my_asprintf(&vm->codecache_dir, "%s/webspl_cache", basedir);
	vm->runloop = spl_simple_runloop;

	spl_builtin_register_all(vm);
	spl_clib_reg(vm, "write", spl_mod_cgi_write, 0);

	vm->cgi_ctx = spl_mod_cgi_get_cgi_ctx(0, cfg);

	if ( !*vm->cgi_ctx->session ) {
respawn_this_session:
		free(vm->cgi_ctx->session);
		vm->cgi_ctx->session = get_new_session();

		get_session_lock(basedir, vm->cgi_ctx->session);

		int script_file_len = strlen(script_file);

		if (script_file_len > 8 && !strcmp(script_file+script_file_len-8, ".websplb"))
		{
			struct spl_code *code = spl_code_get(0);
			code->code_type = SPL_CODE_MAPPED;
			code->code = spl_mmap_file(script_file, &code->size);
			if (!code->code) {
				spl_report(SPL_REPORT_HOST, vm, "Can't open bytecode file!\n");
				spl_code_put(code);
				return 1;
			}
			task = spl_task_create(vm, "main");
			task->flags |= SPL_TASK_FLAG_PUBLIC;
			spl_task_setcode(task, code);
			task->code->id = strdup(script_file);
		}
		else
		{
			char *spl_source = spl_malloc_file(script_file, 0);
			if ( !spl_source ) { spl_report(SPL_REPORT_HOST, vm, "Can't open script file!\n"); return 1; }

			struct spl_asm *as = spl_asm_create();
			as->vm = vm;

			if ( spl_compiler(as, spl_source, script_file, spl_malloc_file, 1) ) return 1;
			spl_asm_add(as, SPL_OP_HALT, "1");
			spl_optimizer(as);

			task = spl_task_create(vm, "main");
			task->flags |= SPL_TASK_FLAG_PUBLIC;

			spl_task_setcode(task, spl_asm_dump(as));
			task->code->id = strdup(script_file);
			spl_asm_destroy(as);
			free(spl_source);
		}
	} else {
		char *dumpfile;
		my_asprintf(&dumpfile, "%s/webspl_cache/%.*s.spld", basedir,
			(int)strcspn(vm->cgi_ctx->session, ":"), vm->cgi_ctx->session);

		get_session_lock(basedir, vm->cgi_ctx->session);

		FILE *f = fopen(dumpfile, "r");
		if (!f) {
			if (cgi_config_get_int(cfg, "spl.respawnsessions")) {
				free_session_lock(basedir, vm->cgi_ctx->session);
				goto respawn_this_session;
			}
			const char *expirelocation = cgi_config_get_str(cfg, "spl.expirelocation");
			if (expirelocation)
				printf("Content-Type: text/html\n\n"
					"<script>location.href = '%s';</script>\n"
					"&nbsp;\n", expirelocation);
			else
				spl_report(SPL_REPORT_HOST, vm, "Can't read dumpfile!\n");
			free_session_lock(basedir, vm->cgi_ctx->session);
			return 1;
		}
		spl_restore_ascii(vm, f);
		fclose(f);

		char *task_name = strchr(vm->cgi_ctx->session, ':');
		if ( task_name ) task = spl_task_lookup(vm, task_name+1);
		else task = spl_task_lookup(vm, "main");

		if ( !task || !(task->flags & SPL_TASK_FLAG_PUBLIC) ) {
			spl_report(SPL_REPORT_HOST, vm, "Can't find task or task is not public!\n");
			free_session_lock(basedir, vm->cgi_ctx->session);
			return 1;
		}

		task->flags &= ~SPL_TASK_FLAG_PAUSED;
	}

	while ( task && task->code ) {
		spl_gc_maybe(vm);
		task = spl_schedule(task);
		if ( spl_exec(task) < 0 ) break;
	}

	char *dumpfile;
	my_asprintf(&dumpfile, "%s/webspl_cache/%.*s.spld", basedir, (int)strcspn(vm->cgi_ctx->session, ":"), vm->cgi_ctx->session);

	task = spl_task_lookup(vm, "main");
	if ( task && task->code ) {
		FILE *f = fopen(dumpfile, "w");
		if ( f ) {
			if (spl_dump_ascii(vm, f))
				spl_report(SPL_REPORT_HOST, vm, "Dump failed: %s\n", dumpfile);
			fclose(f);
		} else
			spl_report(SPL_REPORT_HOST, vm, "Can't write dumpfile: %s\n", dumpfile);
	} else
		unlink(dumpfile);
	free(dumpfile);

	free_session_lock(basedir, vm->cgi_ctx->session);

	if (vm->cgi_ctx) {
		if (vm->cgi_ctx->config) {
			cgi_config_free(vm->cgi_ctx->config);
			vm->cgi_ctx->config = 0;
		}
		spl_mod_cgi_free_cgi_ctx(vm->cgi_ctx);
		vm->cgi_ctx = 0;
	}

	spl_vm_destroy(vm);
	return 0;
}