/*
 * Copyright (C) 2004-2007 Andre Noll <maan@systemlinux.org>
 *
 * Licensed under the GPL v2. For licencing details see COPYING.
 */

/** \file random_selector.c An audio file selector which chooses files by random */

#include <sys/time.h> /* gettimeofday */
#include "server.cmdline.h"
#include "server.h"
#include "afs_common.h"
#include "error.h"
#include "net.h"
#include "string.h"
#include "random_selector_command_list.h"

extern struct misc_meta_data *mmd;

static unsigned int num_audio_files, audio_file_count;
static char **audio_file_list;

static int count_audio_files(__a_unused const char *dir, __a_unused const char *name)
{
	num_audio_files++;
	return 1;
}

static int remember_file(const char *dir, const char *name)
{
	if (audio_file_count < num_audio_files) {
		audio_file_list[audio_file_count] =
			make_message("%s/%s", dir, name);
		audio_file_count++;
	}
	return 1;
}

int com_random_info(int fd, __a_unused int argc, __a_unused char *argv[])
{
	return send_buffer(fd, "Don't use for huge directories as it is "
		"very inefficient in this case.\n");
}

/*
 * Load a list of all audio files into memory and chose num of them randomly.
 * Called by server to determine next audio file to be streamed.
 */
static char **random_get_audio_file_list(unsigned int num)
{
	int i, ret;
	unsigned int len;
	char **ret_list = NULL; /* what we are going to return */

	audio_file_list = NULL;
	num_audio_files = 0;
	/* first run, just count all audio files. dopey */
	ret = find_audio_files(conf.random_dir_arg, count_audio_files);
	if (ret < 0)
		goto out;
	ret = -E_NOTHING_FOUND;
	if (!num_audio_files)
		goto out;
	/* yeah, that doesn't scale, also dopey */
	audio_file_list = para_malloc(num_audio_files * sizeof(char *));
	audio_file_count = 0;
	/* second run (hot dentry cache, hopefully), fill audio_file_list */
	ret = find_audio_files(conf.random_dir_arg, remember_file);
	if (ret < 0)
		goto out;
	/* careful, files might got deleted underneath */
	num_audio_files = audio_file_count; /* can only decrease */
	len = PARA_MIN(num, num_audio_files);
	ret = -E_NOTHING_FOUND;
	if (!len) /* nothing found, return NULL */
		goto out;
	/* success, return NULL-terminated list */
	ret_list = para_calloc((len + 1) * sizeof(char *));
	for (i = 0; i < len; i++) { /* choose randomly */
		int r = (int) ((num_audio_files + 0.0) * (rand()
			/ (RAND_MAX + 1.0)));
		ret_list[i] = para_strdup(audio_file_list[r]);
	}
	ret = 1;
out:
	if (audio_file_list) {
		for (i = 0; i < num_audio_files; i++)
			free(audio_file_list[i]);
		free(audio_file_list);
	}
	if (ret > 0) {
	} else
		sprintf(mmd->selector_info, "dbinfo1:%s\n", PARA_STRERROR(-ret));
	return ret_list;
}

static void random_update_audio_file(char *audio_file)
{
	char *dn = para_dirname(audio_file);
	snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
		"dbinfo1:current dir: %s\n"
		"dbinfo2:random_dir: %s\n"
		"dbinfo3:%d files available\n",
		dn, conf.random_dir_arg, num_audio_files);
	free(dn);
	mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
}
static void random_shutdown(void)
{
}

/**
 * the init function for the random audio file selector
 *
 * \param s pointer ro the struct to iniitalize
 *
 * Init all function pointers of \a s, init the info text and seed the PRNG.
 *
 * \sa struct audio_file_selector, misc_meta_data::selector_info, mysql.c
 */
int random_selector_init(struct audio_file_selector *s)
{
	struct timeval now;
	unsigned int seed;

	PARA_INFO_LOG("%s", "registering random handlers ;)\n");
	gettimeofday(&now, NULL);
	seed = now.tv_usec;
	srand(seed);
	s->cmd_list = random_selector_cmds;
	s->get_audio_file_list = random_get_audio_file_list;
	s->shutdown = random_shutdown;
	s->update_audio_file = random_update_audio_file;
	snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
		"dbinfo1: Welcome to the random selector\n"
		"dbinfo2: random_dir: %s\n", conf.random_dir_arg);
	mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
	return 1;
}