/*
 * libcsync -- a library to sync a directory with another
 *
 * Copyright (c) 2008      by Andreas Schneider <mail@cynapses.org>
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <errno.h>
#include <fnmatch.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>

#include "c_lib.h"
#include "csync_private.h"
#include "csync_config.h"
#include "csync_exclude.h"
#include "csync_lock.h"
#include "csync_statedb.h"
#include "csync_time.h"
#include "csync_util.h"

#include "csync_update.h"
#include "csync_reconcile.h"
#include "csync_propagate.h"

#include "vio/csync_vio.h"

#define CSYNC_LOG_CATEGORY_NAME "csync.api"
#include "csync_log.h"

static int _key_cmp(const void *key, const void *data) {
  uint64_t a;
  csync_file_stat_t *b;

  a = *(uint64_t *) (key);
  b = (csync_file_stat_t *) data;

  if (a < b->phash) {
    return -1;
  } else if (a > b->phash) {
    return 1;
  }

  return 0;
}

static int _data_cmp(const void *key, const void *data) {
  csync_file_stat_t *a, *b;

  a = (csync_file_stat_t *) key;
  b = (csync_file_stat_t *) data;

  if (a->phash < b->phash) {
    return -1;
  } else if (a->phash > b->phash) {
    return 1;
  }

  return 0;
}

int csync_create(CSYNC **csync, const char *local, const char *remote) {
  CSYNC *ctx;
  size_t len = 0;

  ctx = c_malloc(sizeof(CSYNC));
  if (ctx == NULL) {
    return -1;
  }

  /* remove trailing slashes */
  len = strlen(local);
  while(len > 0 && local[len - 1] == '/') --len;

  ctx->local.uri = c_strndup(local, len);
  if (ctx->local.uri == NULL) {
    return -1;
  }

  /* remove trailing slashes */
  len = strlen(remote);
  while(len > 0 && remote[len - 1] == '/') --len;

  ctx->remote.uri = c_strndup(remote, len);
  if (ctx->remote.uri == NULL) {
    SAFE_FREE(ctx->remote.uri);
    return -1;
  }

  ctx->options.max_depth = MAX_DEPTH;
  ctx->options.max_time_difference = MAX_TIME_DIFFERENCE;
  ctx->options.unix_extensions = 0;

  ctx->pwd.uid = getuid();
  ctx->pwd.euid = geteuid();

  if (asprintf(&ctx->options.config_dir, "%s/%s", getenv("HOME"),
        CSYNC_CONF_DIR) < 0) {
    SAFE_FREE(ctx->local.uri);
    SAFE_FREE(ctx->remote.uri);
    SAFE_FREE(ctx);
    errno = ENOMEM;
    return -1;
  }

  *csync = ctx;
  return 0;
}

int csync_init(CSYNC *ctx) {
  int rc;
  time_t timediff = -1;
  char *log = NULL;
  char *exclude = NULL;
  char *lock = NULL;
  char *config = NULL;
  char errbuf[256] = {0};

  if (ctx == NULL) {
    errno = EBADF;
    return -1;
  }

  /* Do not initialize twice */
  if (ctx->status & CSYNC_STATUS_INIT) {
    return 1;
  }

  /* load log file */
  if (csync_log_init() < 0) {
    fprintf(stderr, "csync_init: logger init failed\n");
    return -1;
  }

  /* create dir if it doesn't exist */
  if (! c_isdir(ctx->options.config_dir)) {
    c_mkdirs(ctx->options.config_dir, 0700);
  }

  if (asprintf(&log, "%s/%s", ctx->options.config_dir, CSYNC_LOG_FILE) < 0) {
    rc = -1;
    goto out;
  }

  /* load log if it exists */
  if (c_isfile(log)) {
    csync_log_load(log);
  } else {
    if (c_copy(SYSCONFDIR "/csync/" CSYNC_LOG_FILE, log, 0644) == 0) {
      csync_log_load(log);
    }
  }

  /* create lock file */
  if (asprintf(&lock, "%s/%s", ctx->options.config_dir, CSYNC_LOCK_FILE) < 0) {
    rc = -1;
    goto out;
  }

  if (csync_lock(lock) < 0) {
    rc = -1;
    goto out;
  }

  /* load config file */
  if (asprintf(&config, "%s/%s", ctx->options.config_dir, CSYNC_CONF_FILE) < 0) {
    rc = -1;
    goto out;
  }

  if (csync_config_load(ctx, config) < 0) {
    rc = -1;
    goto out;
  }

  /* load global exclude list */
  if (asprintf(&exclude, "%s/csync/%s", SYSCONFDIR, CSYNC_EXCLUDE_FILE) < 0) {
    rc = -1;
    goto out;
  }

  if (csync_exclude_load(ctx, exclude) < 0) {
    CSYNC_LOG(CSYNC_LOG_PRIORITY_INFO, "Could not load %s - %s", exclude,
        strerror_r(errno, errbuf, sizeof(errbuf)));
  }
  SAFE_FREE(exclude);

  /* load exclude list */
  if (asprintf(&exclude, "%s/%s", ctx->options.config_dir,
        CSYNC_EXCLUDE_FILE) < 0) {
    rc = -1;
    goto out;
  }

  if (csync_exclude_load(ctx, exclude) < 0) {
    CSYNC_LOG(CSYNC_LOG_PRIORITY_INFO, "Could not load %s - %s", exclude, 
        strerror_r(errno, errbuf, sizeof(errbuf)));
  }

  /* create/load statedb */
  if (! csync_is_statedb_disabled(ctx)) {
    uint64_t h = csync_create_statedb_hash(ctx);
    if (asprintf(&ctx->statedb.file, "%s/csync_statedb_%llu.db",
          ctx->options.config_dir, (long long unsigned int) h) < 0) {
      rc = -1;
      goto out;
    }
    CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG, "Remote replica: %s", ctx->remote.uri);
    CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG, "Statedb: %s", ctx->statedb.file);

    if (csync_statedb_load(ctx, ctx->statedb.file) < 0) {
      rc = -1;
      goto out;
    }
  }

  ctx->local.type = LOCAL_REPLICA;

  /* check for uri */
  if (fnmatch("*://*", ctx->remote.uri, 0) == 0) {
    size_t len;
    len = strstr(ctx->remote.uri, "://") - ctx->remote.uri;
    /* get protocol */
    if (len > 0) {
      char *module = NULL;
      /* module name */
      module = c_strndup(ctx->remote.uri, len);
      if (module == NULL) {
        rc = -1;
        goto out;
      }
      /* load module */
      rc = csync_vio_init(ctx, module, NULL);
      SAFE_FREE(module);
      if (rc < 0) {
        goto out;
      }
      ctx->remote.type = REMOTE_REPLCIA;
    }
  } else {
    ctx->remote.type = LOCAL_REPLICA;
  }

  timediff = csync_timediff(ctx);
  if (timediff > ctx->options.max_time_difference) {
    CSYNC_LOG(CSYNC_LOG_PRIORITY_FATAL,
        "Clock skew detected. The time difference is greater than %d seconds!",
        ctx->options.max_time_difference);
    rc = -1;
    goto out;
  } else if (timediff < 0) {
    CSYNC_LOG(CSYNC_LOG_PRIORITY_FATAL, "Synchronisation is not possible!");
    rc = -1;
    goto out;
  }

  if (csync_unix_extensions(ctx) < 0) {
    CSYNC_LOG(CSYNC_LOG_PRIORITY_FATAL, "Could not detect filesystem type.");
    rc = -1;
    goto out;
  }

  if (c_rbtree_create(&ctx->local.tree, _key_cmp, _data_cmp) < 0) {
    rc = -1;
    goto out;
  }

  if (c_rbtree_create(&ctx->remote.tree, _key_cmp, _data_cmp) < 0) {
    rc = -1;
    goto out;
  }

  ctx->status = CSYNC_STATUS_INIT;

  rc = 0;

out:
  SAFE_FREE(log);
  SAFE_FREE(lock);
  SAFE_FREE(exclude);
  SAFE_FREE(config);
  return rc;
}

int csync_update(CSYNC *ctx) {
  int rc = -1;
  struct timespec start, finish;

  if (ctx == NULL) {
    errno = EBADF;
    return -1;
  }

  csync_memstat_check();

  /* update detection for local replica */
  clock_gettime(CLOCK_REALTIME, &start);
  ctx->current = LOCAL_REPLICA;
  ctx->replica = ctx->local.type;

  rc = csync_ftw(ctx, ctx->local.uri, csync_walker, MAX_DEPTH);

  clock_gettime(CLOCK_REALTIME, &finish);

  CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG,
      "Update detection for local replica took %.2f seconds walking %zu files.",
      c_secdiff(finish, start), c_rbtree_size(ctx->local.tree));
  csync_memstat_check();

  if (rc < 0) {
    return -1;
  }

  /* update detection for remote replica */
  clock_gettime(CLOCK_REALTIME, &start);
  ctx->current = REMOTE_REPLCIA;
  ctx->replica = ctx->remote.type;

  rc = csync_ftw(ctx, ctx->remote.uri, csync_walker, MAX_DEPTH);

  clock_gettime(CLOCK_REALTIME, &finish);

  CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG,
      "Update detection for remote replica took %.2f seconds "
      "walking %zu files.",
      c_secdiff(finish, start), c_rbtree_size(ctx->remote.tree));
  csync_memstat_check();

  if (rc < 0) {
    return -1;
  }

  ctx->status |= CSYNC_STATUS_UPDATE;

  return 0;
}

int csync_reconcile(CSYNC *ctx) {
  int rc = -1;
  struct timespec start, finish;

  if (ctx == NULL) {
    errno = EBADF;
    return -1;
  }

  /* Reconciliation for local replica */
  clock_gettime(CLOCK_REALTIME, &start);

  ctx->current = LOCAL_REPLICA;
  ctx->replica = ctx->local.type;

  rc = csync_reconcile_updates(ctx);

  clock_gettime(CLOCK_REALTIME, &finish);

  CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG,
      "Reconciliation for local replica took %.2f seconds visiting %zu files.",
      c_secdiff(finish, start), c_rbtree_size(ctx->local.tree));

  if (rc < 0) {
    return -1;
  }

  /* Reconciliation for local replica */
  clock_gettime(CLOCK_REALTIME, &start);

  ctx->current = REMOTE_REPLCIA;
  ctx->replica = ctx->remote.type;

  rc = csync_reconcile_updates(ctx);

  clock_gettime(CLOCK_REALTIME, &finish);

  CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG,
      "Reconciliation for remote replica took %.2f seconds visiting %zu files.",
      c_secdiff(finish, start), c_rbtree_size(ctx->remote.tree));

  if (rc < 0) {
    return -1;
  }

  ctx->status |= CSYNC_STATUS_RECONCILE;

  return 0;
}

int csync_propagate(CSYNC *ctx) {
  int rc = -1;
  struct timespec start, finish;

  if (ctx == NULL) {
    errno = EBADF;
    return -1;
  }

  /* Reconciliation for local replica */
  clock_gettime(CLOCK_REALTIME, &start);

  ctx->current = LOCAL_REPLICA;
  ctx->replica = ctx->local.type;

  rc = csync_propagate_files(ctx);

  clock_gettime(CLOCK_REALTIME, &finish);

  CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG,
      "Propagation for local replica took %.2f seconds visiting %zu files.",
      c_secdiff(finish, start), c_rbtree_size(ctx->local.tree));

  if (rc < 0) {
    return -1;
  }

  /* Reconciliation for local replica */
  clock_gettime(CLOCK_REALTIME, &start);

  ctx->current = REMOTE_REPLCIA;
  ctx->replica = ctx->remote.type;

  rc = csync_propagate_files(ctx);

  clock_gettime(CLOCK_REALTIME, &finish);

  CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG,
      "Propagation for remote replica took %.2f seconds visiting %zu files.",
      c_secdiff(finish, start), c_rbtree_size(ctx->remote.tree));

  if (rc < 0) {
    return -1;
  }

  ctx->status |= CSYNC_STATUS_PROPAGATE;

  return 0;
}

static void _tree_destructor(void *data) {
  csync_file_stat_t *freedata = NULL;

  freedata = (csync_file_stat_t *) data;
  SAFE_FREE(freedata);
}

int csync_destroy(CSYNC *ctx) {
  struct timespec start, finish;
  char *lock = NULL;
  char errbuf[256] = {0};
  int jwritten = 0;

  if (ctx == NULL) {
    errno = EBADF;
    return -1;
  }

  csync_vio_shutdown(ctx);

  /* if we have a statedb */
  if (ctx->statedb.db != NULL) {
    /* and we have successfully synchronized */
    if (ctx->status >= CSYNC_STATUS_DONE) {
      /* merge trees */
      if (csync_merge_file_trees(ctx) < 0) {
        CSYNC_LOG(CSYNC_LOG_PRIORITY_ERROR, "Unable to merge trees: %s",
            strerror_r(errno, errbuf, sizeof(errbuf)));
      } else {
        clock_gettime(CLOCK_REALTIME, &start);
        /* write the statedb to disk */
        if (csync_statedb_write(ctx) == 0) {
          jwritten = 1;
          clock_gettime(CLOCK_REALTIME, &finish);
          CSYNC_LOG(CSYNC_LOG_PRIORITY_DEBUG,
              "Writing the statedb of %zu files to disk took %.2f seconds",
              c_rbtree_size(ctx->local.tree), c_secdiff(finish, start));
        } else {
          CSYNC_LOG(CSYNC_LOG_PRIORITY_ERROR, "Unable to write statedb: %s",
              strerror_r(errno, errbuf, sizeof(errbuf)));
        }
      }
    }
    csync_statedb_close(ctx, ctx->statedb.file, jwritten);
  }

  /* clear exclude list */
  csync_exclude_destroy(ctx);

  /* remove the lock file */
  if (asprintf(&lock, "%s/%s", ctx->options.config_dir, CSYNC_LOCK_FILE) > 0) {
    csync_lock_remove(lock);
  }

  /* stop logging */
  csync_log_fini();

  /* destroy the rbtrees */
  if (c_rbtree_size(ctx->local.tree) > 0) {
    c_rbtree_destroy(ctx->local.tree, _tree_destructor);
  }

  if (c_rbtree_size(ctx->remote.tree) > 0) {
    c_rbtree_destroy(ctx->remote.tree, _tree_destructor);
  }

  /* free memory */
  c_rbtree_free(ctx->local.tree);
  c_list_free(ctx->local.list);
  c_rbtree_free(ctx->remote.tree);
  c_list_free(ctx->remote.list);
  SAFE_FREE(ctx->local.uri);
  SAFE_FREE(ctx->remote.uri);
  SAFE_FREE(ctx->options.config_dir);
  SAFE_FREE(ctx->statedb.file);

  SAFE_FREE(ctx);

  SAFE_FREE(lock);

  return 0;
}

/* Check if csync is the required version or get the version string. */
const char *csync_version(int req_version) {
  if (req_version <= LIBCSYNC_VERSION_INT) {
    return CSYNC_STRINGIFY(LIBCSYNC_VERSION);
  }

  return NULL;
}

int csync_add_exclude_list(CSYNC *ctx, const char *path) {
  if (ctx == NULL || path == NULL) {
    return -1;
  }

  return csync_exclude_load(ctx, path);
}

const char *csync_get_config_dir(CSYNC *ctx) {
  if (ctx == NULL) {
    return NULL;
  }

  return ctx->options.config_dir;
}

int csync_set_config_dir(CSYNC *ctx, const char *path) {
  if (ctx == NULL || path == NULL) {
    return -1;
  }

  SAFE_FREE(ctx->options.config_dir);
  ctx->options.config_dir = c_strdup(path);
  if (ctx->options.config_dir == NULL) {
    return -1;
  }

  return 0;
}

int csync_enable_statedb(CSYNC *ctx) {
  if (ctx == NULL) {
    return -1;
  }

  if (ctx->status & CSYNC_STATUS_INIT) {
    fprintf(stderr, "This function must be called before initialization.");
    return -1;
  }

  ctx->statedb.disabled = 0;

  return 0;
}

int csync_disable_statedb(CSYNC *ctx) {
  if (ctx == NULL) {
    return -1;
  }

  if (ctx->status & CSYNC_STATUS_INIT) {
    fprintf(stderr, "This function must be called before initialization.");
    return -1;
  }

  ctx->statedb.disabled = 1;

  return 0;
}

int csync_is_statedb_disabled(CSYNC *ctx) {
  if (ctx == NULL) {
    return -1;
  }

  return ctx->statedb.disabled;
}

int csync_set_auth_callback(CSYNC *ctx, csync_auth_callback cb) {
  if (ctx == NULL || cb == NULL) {
    return -1;
  }

  if (ctx->status & CSYNC_STATUS_INIT) {
    fprintf(stderr, "This function must be called before initialization.");
    return -1;
  }

  ctx->auth_callback = cb;

  return 0;
}

const char *csync_get_statedb_file(CSYNC *ctx) {
  if (ctx == NULL) {
    return NULL;
  }

  return c_strdup(ctx->statedb.file);
}

void *csync_get_userdata(CSYNC *ctx) {
  if (ctx == NULL) {
    return NULL;
  }

  return ctx->userdata;
}

int csync_set_userdata(CSYNC *ctx, void *userdata) {
  if (ctx == NULL) {
    return -1;
  }

  ctx->userdata = userdata;

  return 0;
}

csync_auth_callback csync_get_auth_callback(CSYNC *ctx) {
  if (ctx == NULL) {
    return NULL;
  }

  return ctx->auth_callback;
}

int csync_set_status(CSYNC *ctx, int status) {
  if (ctx == NULL || status < 0) {
    return -1;
  }

  ctx->status = status;

  return 0;
}

int csync_get_status(CSYNC *ctx) {
  if (ctx == NULL) {
    return -1;
  }

  return ctx->status;
}

/* vim: set ts=8 sw=2 et cindent: */