#define _GNU_SOURCE
#include <sys/types.h>

#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>

#include "server.h"
#include "connections.h"
#include "response.h"
#include "connections.h"
#include "log.h"

#include "plugin.h"
#ifdef HAVE_FORK
/* no need for waitpid if we don't have fork */
#include <sys/wait.h>
#endif
typedef struct {
	buffer *path_rrdtool_bin;
	buffer *path_rrd;
	
	double requests, *requests_ptr;
	double bytes_written, *bytes_written_ptr;
	double bytes_read, *bytes_read_ptr;
} plugin_config;

typedef struct {
	PLUGIN_DATA;
	
	buffer *cmd;
	buffer *resp;
	
	int read_fd, write_fd;
	pid_t rrdtool_pid;
	
	int rrdtool_running;
	
	plugin_config **config_storage;
	plugin_config conf;
} plugin_data;

INIT_FUNC(mod_rrd_init) {
	plugin_data *p;
	
	p = calloc(1, sizeof(*p));
	
	p->resp = buffer_init();
	p->cmd = buffer_init();
	
	return p;
}

FREE_FUNC(mod_rrd_free) {
	plugin_data *p = p_d;
	size_t i;
	
	if (!p) return HANDLER_GO_ON;
	
	if (p->config_storage) {
		for (i = 0; i < srv->config_context->used; i++) {
			plugin_config *s = p->config_storage[i];
			
			buffer_free(s->path_rrdtool_bin);
			buffer_free(s->path_rrd);
			
			free(s);
		}
	}
	buffer_free(p->cmd);
	buffer_free(p->resp);
	
	free(p->config_storage);
	
	if (p->rrdtool_pid) {
		int status;
		close(p->read_fd);
		close(p->write_fd);
#ifdef HAVE_FORK	
		/* collect status */
		waitpid(p->rrdtool_pid, &status, 0);
#endif
	}
	
	free(p);
	
	return HANDLER_GO_ON;
}

int mod_rrd_create_pipe(server *srv, plugin_data *p) {
	pid_t pid;
	
	int to_rrdtool_fds[2];
	int from_rrdtool_fds[2];
#ifdef HAVE_FORK	
	if (pipe(to_rrdtool_fds)) {
		log_error_write(srv, __FILE__, __LINE__, "ss", 
				"pipe failed: ", strerror(errno));
		return -1;
	}
	
	if (pipe(from_rrdtool_fds)) {
		log_error_write(srv, __FILE__, __LINE__, "ss", 
				"pipe failed: ", strerror(errno));
		return -1;
	}
	
	/* fork, execve */
	switch (pid = fork()) {
	case 0: {
		/* child */
		char **args;
		int argc;
		int i = 0;
		char *dash = "-";
		
		/* move stdout to from_rrdtool_fd[1] */
		close(STDOUT_FILENO);
		dup2(from_rrdtool_fds[1], STDOUT_FILENO);
		close(from_rrdtool_fds[1]);
		/* not needed */
		close(from_rrdtool_fds[0]);
		
		/* move the stdin to to_rrdtool_fd[0] */
		close(STDIN_FILENO);
		dup2(to_rrdtool_fds[0], STDIN_FILENO);
		close(to_rrdtool_fds[0]);
		/* not needed */
		close(to_rrdtool_fds[1]);
		
		close(STDERR_FILENO);
		
		if (srv->errorlog_mode == ERRORLOG_FILE) {
			dup2(srv->errorlog_fd, STDERR_FILENO);
			close(srv->errorlog_fd);
		}
		
		/* set up args */
		argc = 3;
		args = malloc(sizeof(*args) * argc);
		i = 0;
		
		args[i++] = p->conf.path_rrdtool_bin->ptr;
		args[i++] = dash;
		args[i++] = NULL;

		/* we don't need the client socket */
		for (i = 3; i < 256; i++) {
			close(i);
		}
		
		/* exec the cgi */
		execv(args[0], args);
		
		log_error_write(srv, __FILE__, __LINE__, "sss", "spawing rrdtool failed: ", strerror(errno), args[0]);
		
		/* */
		SEGFAULT();
		break;
	}
	case -1:
		/* error */
		log_error_write(srv, __FILE__, __LINE__, "ss", "fork failed: ", strerror(errno));
		break;
	default: {
		/* father */
		
		close(from_rrdtool_fds[1]);
		close(to_rrdtool_fds[0]);
		
		/* register PID and wait for them asyncronously */
		p->write_fd = to_rrdtool_fds[1];
		p->read_fd = from_rrdtool_fds[0];
		p->rrdtool_pid = pid;
		
		break;
	}
	}
	
	return 0;
#else
	return -1;
#endif
}

static int mod_rrdtool_create_rrd(server *srv, plugin_data *p, plugin_config *s) {
	struct stat st;
	
	/* check if DB already exists */
	if (0 == stat(s->path_rrd->ptr, &st)) {
		/* check if it is plain file */
		if (!S_ISREG(st.st_mode)) {
			log_error_write(srv, __FILE__, __LINE__, "sb", 
					"not a regular file:", s->path_rrd);
			return HANDLER_ERROR;
		}
	} else {
		int r ;
		/* create a new one */
		
		BUFFER_COPY_STRING_CONST(p->cmd, "create ");
		buffer_append_string_buffer(p->cmd, s->path_rrd);
		buffer_append_string(p->cmd, " --step 60 ");
		buffer_append_string(p->cmd, "DS:InOctets:ABSOLUTE:600:U:U ");
		buffer_append_string(p->cmd, "DS:OutOctets:ABSOLUTE:600:U:U ");
		buffer_append_string(p->cmd, "DS:Requests:ABSOLUTE:600:U:U ");
		buffer_append_string(p->cmd, "RRA:AVERAGE:0.5:1:600 ");
		buffer_append_string(p->cmd, "RRA:AVERAGE:0.5:6:700 ");
		buffer_append_string(p->cmd, "RRA:AVERAGE:0.5:24:775 ");
		buffer_append_string(p->cmd, "RRA:AVERAGE:0.5:288:797 ");
		buffer_append_string(p->cmd, "RRA:MAX:0.5:1:600 ");
		buffer_append_string(p->cmd, "RRA:MAX:0.5:6:700 ");
		buffer_append_string(p->cmd, "RRA:MAX:0.5:24:775 ");
		buffer_append_string(p->cmd, "RRA:MAX:0.5:288:797 ");
		buffer_append_string(p->cmd, "RRA:MIN:0.5:1:600 ");
		buffer_append_string(p->cmd, "RRA:MIN:0.5:6:700 ");
		buffer_append_string(p->cmd, "RRA:MIN:0.5:24:775 ");
		buffer_append_string(p->cmd, "RRA:MIN:0.5:288:797\n");
		
		if (-1 == (r = write(p->write_fd, p->cmd->ptr, p->cmd->used - 1))) {
			log_error_write(srv, __FILE__, __LINE__, "ss", 
				"rrdtool-write: failed", strerror(errno));
			
			return HANDLER_ERROR;
		}
		
		buffer_prepare_copy(p->resp, 4096);
		if (-1 == (r = read(p->read_fd, p->resp->ptr, p->resp->size))) {
			log_error_write(srv, __FILE__, __LINE__, "ss", 
				"rrdtool-read: failed", strerror(errno));
			
			return HANDLER_ERROR;
		}
		
		p->resp->used = r;
		
		if (p->resp->ptr[0] != 'O' ||
		    p->resp->ptr[1] != 'K') {
			log_error_write(srv, __FILE__, __LINE__, "sbb", 
				"rrdtool-response:", p->cmd, p->resp);
			
			return HANDLER_ERROR;
		}
	}
	
	return HANDLER_GO_ON;
}

#define PATCH(x) \
	p->conf.x = s->x;
static int mod_rrd_patch_connection(server *srv, connection *con, plugin_data *p) {
	size_t i, j;
	plugin_config *s = p->config_storage[0];
	
	PATCH(path_rrdtool_bin);
	PATCH(path_rrd);
	
	p->conf.bytes_written_ptr = &(s->bytes_written);
	p->conf.bytes_read_ptr = &(s->bytes_read);
	p->conf.requests_ptr = &(s->requests);
	
	/* skip the first, the global context */
	for (i = 1; i < srv->config_context->used; i++) {
		data_config *dc = (data_config *)srv->config_context->data[i];
		s = p->config_storage[i];
		
		/* condition didn't match */
		if (!config_check_cond(srv, con, dc)) continue;
		
		/* merge config */
		for (j = 0; j < dc->value->used; j++) {
			data_unset *du = dc->value->data[j];
			
			if (buffer_is_equal_string(du->key, CONST_STR_LEN("rrdtool.db-name"))) {
				PATCH(path_rrd);
				/* get pointers to double values */
				
				p->conf.bytes_written_ptr = &(s->bytes_written);
				p->conf.bytes_read_ptr = &(s->bytes_read);
				p->conf.requests_ptr = &(s->requests);
			}
		}
	}
	
	return 0;
}
#undef PATCH

SETDEFAULTS_FUNC(mod_rrd_set_defaults) {
	plugin_data *p = p_d;
	size_t i;
	
	config_values_t cv[] = { 
		{ "rrdtool.binary",              NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_SERVER },
		{ "rrdtool.db-name",             NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION },
		{ NULL,                          NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
	};
	
	if (!p) return HANDLER_ERROR;
	
	p->config_storage = calloc(1, srv->config_context->used * sizeof(specific_config *));
	
	for (i = 0; i < srv->config_context->used; i++) {
		plugin_config *s;
		
		s = calloc(1, sizeof(plugin_config));
		s->path_rrdtool_bin = buffer_init();
		s->path_rrd = buffer_init();
		s->requests = 0;
		s->bytes_written = 0;
		s->bytes_read = 0;
		
		cv[0].destination = s->path_rrdtool_bin;
		cv[1].destination = s->path_rrd;
		
		p->config_storage[i] = s;
	
		if (0 != config_insert_values_global(srv, ((data_config *)srv->config_context->data[i])->value, cv)) {
			return HANDLER_ERROR;
		}
		
		if (i > 0 && !buffer_is_empty(s->path_rrdtool_bin)) {
			/* path_rrdtool_bin is a global option */
			
			log_error_write(srv, __FILE__, __LINE__, "s", 
					"rrdtool.binary can only be set as a global option.");
			
			return HANDLER_ERROR;
		}
		
	}
	
	p->conf.path_rrdtool_bin = p->config_storage[0]->path_rrdtool_bin;
	p->rrdtool_running = 0;
	
	/* check for dir */
	
	if (buffer_is_empty(p->conf.path_rrdtool_bin)) {
		log_error_write(srv, __FILE__, __LINE__, "s", 
				"rrdtool.binary has to be set");
		return HANDLER_ERROR;
	}
	
	/* open the pipe to rrdtool */
	if (mod_rrd_create_pipe(srv, p)) {
		return HANDLER_ERROR;
	}
	
	p->rrdtool_running = 1;
		
	return HANDLER_GO_ON;
}

TRIGGER_FUNC(mod_rrd_trigger) {
	plugin_data *p = p_d;
	size_t i;
	
	if (!p->rrdtool_running) return HANDLER_GO_ON;
	if ((srv->cur_ts % 60) != 0) return HANDLER_GO_ON;
	
	for (i = 0; i < srv->config_context->used; i++) {
		plugin_config *s = p->config_storage[i];
		int r;
		
		if (buffer_is_empty(s->path_rrd)) continue;
	
		/* write the data down every minute */
		
		if (HANDLER_GO_ON != mod_rrdtool_create_rrd(srv, p, s)) return HANDLER_ERROR;
		
		BUFFER_COPY_STRING_CONST(p->cmd, "update ");
		buffer_append_string_buffer(p->cmd, s->path_rrd);
		BUFFER_APPEND_STRING_CONST(p->cmd, " N:");
		buffer_append_off_t(p->cmd, s->bytes_read);
		BUFFER_APPEND_STRING_CONST(p->cmd, ":");
		buffer_append_off_t(p->cmd, s->bytes_written);
		BUFFER_APPEND_STRING_CONST(p->cmd, ":");
		buffer_append_long(p->cmd, s->requests);
		BUFFER_APPEND_STRING_CONST(p->cmd, "\n");
		
		if (-1 == (r = write(p->write_fd, p->cmd->ptr, p->cmd->used - 1))) {
			p->rrdtool_running = 0;
			
			log_error_write(srv, __FILE__, __LINE__, "ss", 
					"rrdtool-write: failed", strerror(errno));
			
			return HANDLER_ERROR;
		}
		
		buffer_prepare_copy(p->resp, 4096);
		if (-1 == (r = read(p->read_fd, p->resp->ptr, p->resp->size))) {
			p->rrdtool_running = 0;
			
			log_error_write(srv, __FILE__, __LINE__, "ss", 
					"rrdtool-read: failed", strerror(errno));
			
			return HANDLER_ERROR;
		}
		
		p->resp->used = r;
		
		if (p->resp->ptr[0] != 'O' ||
		    p->resp->ptr[1] != 'K') {
			p->rrdtool_running = 0;
			
			log_error_write(srv, __FILE__, __LINE__, "sbb", 
					"rrdtool-response:", p->cmd, p->resp);
			
			return HANDLER_ERROR;
		}
		s->requests = 0;
		s->bytes_written = 0;
		s->bytes_read = 0;
	}
	
	return HANDLER_GO_ON;
}

REQUESTDONE_FUNC(mod_rrd_account) {
	plugin_data *p = p_d;
	
	mod_rrd_patch_connection(srv, con, p);
	
	*(p->conf.requests_ptr)      += 1;
	*(p->conf.bytes_written_ptr) += con->bytes_written;
	*(p->conf.bytes_read_ptr)    += con->bytes_read;
	
	return HANDLER_GO_ON;
}

int mod_rrdtool_plugin_init(plugin *p) {
	p->version     = LIGHTTPD_VERSION_ID;
	p->name        = buffer_init_string("rrd");
	
	p->init        = mod_rrd_init;
	p->cleanup     = mod_rrd_free;
	p->set_defaults= mod_rrd_set_defaults;
	
	p->handle_trigger      = mod_rrd_trigger;
	p->handle_request_done = mod_rrd_account;
	
	p->data        = NULL;
	
	return 0;
}