<?php

/**
 * Implements hook_field_storage_info().
 */
function tripal_chado_field_storage_info() {
  return array(
    'field_chado_storage' => array(
      'label' => t('Chado'),
      'description' => t('Stores fields in the local Chado database.'),
      'settings' => array(),
      // The logo_url key is supported by Tripal. It's not a Drupal key. It's
      // used for adding a logo or picture for the data store to help make it
      // more easily recognized on the  field_ui_field_overview_form. Ideally
      // the URL should point to a relative path on the local Drupal site.
      'logo_url' => url(drupal_get_path('module', 'tripal') . '/theme/images/250px-ChadoLogo.png'),
    ),
  );
}

/**
 * Implements hook_field_storage_write().
 */
function tripal_chado_field_storage_write($entity_type, $entity, $op, $fields) {

  // Get the bundle and the term for this entity.
  $bundle = tripal_load_bundle_entity(array('name' => $entity->bundle));
  $term = entity_load('TripalTerm', array('id' => $entity->term_id));
  $term = reset($term);

  // Convert the Tripal term entity into the appropriate record in Chado.
  $dbxref = tripal_get_dbxref(array('accession' => $term->accession, 'db_id' => array('name' => $term->vocab->vocabulary)));
  $cvterm = tripal_get_cvterm(array('dbxref_id' => $dbxref->dbxref_id));

  // Get the base table, type field and record_id from the entity.
  $base_table = $entity->chado_table;
  $type_field = $entity->chado_column;
  $record     = $entity->chado_record;
  $record_id  = $entity->chado_record_id;
  $base_schema = chado_get_schema($base_table);
  $base_pkey = $base_schema['primary key'][0];

  // Convert the fields into a key/value list of fields and their values.
  $field_vals = tripal_chado_field_storage_write_merge_fields($fields, $entity_type, $entity);

  // First, write the record for the base table.  If we have a record id then
  // this is an update and we need to set the primary key.  If not, then this
  // is an insert and we need to set the type_id if the table supports it.
  $values = $field_vals[$base_table];
  if ($record_id) {
    $values[$base_pkey] = $record_id;
  }
  elseif ($type_field) {
    $values[$type_field] = $cvterm->cvterm_id;
  }
  $base_record_id = tripal_chado_field_storage_write_table($base_table, $values);

  // If this is an insert then add the chado_entity record.
  if ($op == FIELD_STORAGE_INSERT) {
    // Add a record to the chado_entity table so that the data for the
    // fields can be pulled from Chado when loaded the next time.
    $record = array(
      'entity_id' => $entity->id,
      'record_id' => $base_record_id,
      'data_table' => $base_table,
    );
    $success = drupal_write_record('chado_entity', $record);
    if (!$success) {
      drupal_set_message('Unable to insert new Chado entity.', 'error');
    }
  }

  // Now that we have handled the base table, we need to handle linking tables.
  foreach ($field_vals as $table_name => $details) {
    // Skip the base table as we've already dealt with it.
    if ($table_name == $base_table) {
      continue;
    }
    foreach ($details as $delta => $values) {
      $record_id = tripal_chado_field_storage_write_table($table_name, $values);
    }
  }
}

/**
 * Write (inserts/updates/deletes) values for a Chado table.
 *
 * The $values array is of the same format used by chado_insert_record() and
 * chado_update_record().  However, both of those methods will use any nested
 * arrays (i.e. representing foreign keys) to select an appropriate record ID
 * that can be substituted as the value.  Here, the nested arrays are
 * either inserted or updated as well, but the choice is determined if the
 * primary key value is present.  If present an update occurs, if not present
 * then an insert occurs.
 *
 * This function is recursive and nested arrays from the lowest point of the
 * "tree" are dealt with first.
 *
 * @param $table_name
 *   The name of the table on which the insertion/update is performed.
 * @param $values
 *   The values array for the insertion.
 *
 * @throws Exception
 *
 * @return
 *   The unique record ID.
 */
function tripal_chado_field_storage_write_table($table_name, $values) {
  $schema = chado_get_schema($table_name);
  $fkeys = $schema['foreign keys'];
  $pkey = $schema['primary key'][0];


  // Fields with a cardinality greater than 1 will often submit an
  // empty form.  We want to remove these empty submissions.  We can detect
  // them if all of the fields are empty.
  $num_empty = 0;
  foreach ($values as $column => $value) {
    if (!$value) {
      $num_empty++;
    }
  }
  if ($num_empty == count(array_keys($values))) {
    return '';
  }

  // If the primary key column has a value but all other values are empty then
  // this is a delete.
  if (array_key_exists($pkey, $values) and $values[$pkey]) {
    $num_vals = 0;
    foreach ($values as $value) {
      if ($value) {
        $num_vals++;
      }
    }
    if ($num_vals == 1) {
      $new_vals[$pkey] = $values[$pkey];
      if (!chado_delete_record($table_name, $new_vals)) {
        throw new Exception('Could not delete record from table: "' . $table_name . '".');
      }
      return '';
    }
  }

  // If the primary key column does not have a value then this is an insert.
  if (!array_key_exists($pkey, $values) or !$values[$pkey] or !isset($values[$pkey])) {
    // Before inserting, we want to make sure the record does not
    // already exist.  Using the unique constraint check for a matching record.
    $options = array('is_duplicate' => TRUE);
    $is_duplicate = chado_select_record($table_name, array('*'), $values, $options);
    if($is_duplicate) {
      $record = chado_select_record($table_name, array('*'), $values);
      return $record[0]->$pkey;
    }

    // Insert the values array as a new record in the table but remove the
    // pkey as it should be set.
    $new_vals = $values;
    unset($new_vals[$pkey]);
    $record = chado_insert_record($table_name, $new_vals);
    if ($record === FALSE) {
      throw new Exception('Could not insert Chado record into table: "' . $table_name . '".');
    }
    return $record[$pkey];
  }

  // If we've made it to this point then this is an update.
  // TODO: what if the unique constraint matches another record?  That is
  // not being tested for here.
  $match[$pkey] = $values[$pkey];
  if (!chado_update_record($table_name, $match, $values)) {
    drupal_set_message("Could not update Chado record in table: $table_name.", 'error');
  }
  return $values[$pkey];
}

/**
 * Implements hook_field_storage_load().
 *
 * Responsible for loading the fields from the Chado database and adding
 * their values to the entity.
 */
function tripal_chado_field_storage_load($entity_type, $entities, $age,
    $fields, $options) {

  $load_current = $age == FIELD_LOAD_CURRENT;
  global $language;
  $langcode = $language->language;

  foreach ($entities as $id => $entity) {

    if (property_exists($entity, 'chado_table')) {
      // Get the base table and record id for the fields of this entity.
      $base_table = $entity->chado_table;
      $type_field = $entity->chado_column;
      $record_id  = $entity->chado_record_id;
   }
    else {
      $bundle = tripal_load_bundle_entity(array('name' => $entity->bundle));
      $base_table = $bundle->data_table;
      $type_field = $bundle->type_column;

      // Get the base table and record id for the fields of this entity.
      $details = db_select('chado_entity', 'ce')
        ->fields('ce')
        ->condition('entity_id', $entity->id)
        ->execute()
        ->fetchObject();
      if (!$details) {
        // TODO: what to do if record is missing!
      }
      $record_id  = isset($details->record_id) ? $details->record_id : '';
    }

    // Get this table's schema.
    $schema = chado_get_schema($base_table);
    $pkey_field = $schema['primary key'][0];

    // Get the base record if one exists
    $columns = array('*');
    $match = array($pkey_field => $record_id);
    $record = chado_generate_var($base_table, $match);
    $entity->chado_record = $record;

    // Iterate through the entity's fields so we can get the column names
    // that need to be selected from each of the tables represented.
    $tables = array();
    foreach ($fields as $field_id => $ids) {
      // By the time this hook runs, the relevant field definitions have been
      // populated and cached in FieldInfo, so calling field_info_field_by_id()
      // on each field individually is more efficient than loading all fields in
      // memory upfront with field_info_field_by_ids().
      $field = field_info_field_by_id($field_id);
      $field_name = $field['field_name'];
      $field_type = $field['type'];
      $field_module = $field['module'];

      // Get the instnace for this field
      $instance = field_info_instance($entity_type, $field_name, $entity->bundle);

      // Skip fields that don't map to a Chado table (e.g. kvproperty_adder).
      if (!array_key_exists('settings', $instance) or !array_key_exists('chado_table', $instance['settings'])) {
        continue;
      }

      // Get the Chado table and column for this field.
      $field_table = $instance['settings']['chado_table'];
      $field_column = $instance['settings']['chado_column'];

      // There are only two types of fields: 1) fields that represent a single
      // column of the base table, or 2) fields that represent a linked record
      // in a many-to-one relationship with the base table.

      // Type 1: fields from base tables.
      if ($field_table == $base_table) {
        // Set an empty value by default, and if there is a record, then update.
        $entity->{$field_name}['und'][0]['value'] = '';
        if ($record and property_exists($record, $field_column)) {
          // If the field column is an object then it's a FK to another table.
          // and because $record object is created by the chado_generate_var()
          // function we must go one more level deeper to get the value
          if (is_object($record->$field_column)) {
            $entity->{$field_name}['und'][0]['chado-' . $field_table . '__' . $field_column] = $record->$field_column->$field_column;
          }
          else {
            // For non FK fields we'll make the field value be the same
            // as the column value.
            $entity->{$field_name}['und'][0]['value'] = $record->$field_column;
            $entity->{$field_name}['und'][0]['chado-' . $field_table . '__' . $field_column] = $record->$field_column;
          }
        }

        // Allow the creating module to alter the value if desired.  The
        // module should do this if the field has any other form elements
        // that need populationg besides the value which was set above.
        tripal_load_include_field_class($field_type);
        if (class_exists($field_type) and is_subclass_of($field_type, 'TripalField')) {
          $tfield = new $field_type($field, $instance);
          $tfield->load($entity, array('record' => $record));
        }
      }

      // Type 2: fields for linked records.  These fields will have any number
      // of form elements that might need populating so we'll offload the
      // loading of these fields to the field itself.
      if ($field_table != $base_table) {

        // Set an empty value by default, and let the hook function update it.
        $entity->{$field_name}['und'][0]['value'] = '';
        tripal_load_include_field_class($field_type);
        if (class_exists($field_type) && method_exists($field_type, 'load')) {
          $tfield = new $field_type($field, $instance);
          $tfield->load($entity, array('record' => $record));
        }
      }

    } // end: foreach ($fields as $field_id => $ids) {
  } // end: foreach ($entities as $id => $entity) {
}
/**
 * Merges the values of all fields into a single array keyed by table name.
 */
function tripal_chado_field_storage_write_merge_fields($fields, $entity_type, $entity) {
  $all_fields = array();
  $base_fields = array();

  // Iterate through all of the fields and organize them into a
  // new fields array keyed by the table name
  foreach ($fields as $field_id => $ids) {

    // Get the field name and information about it.
    $field = field_info_field_by_id($field_id);
    $field_name = $field['field_name'];
    // Some fields (e.g. chado_linker_cvterm_adder) don't add data to
    // Chado so they don't have a table, but they are still attached to the
    // entity. Just skip these.
    if (!array_key_exists('chado_table', $field['settings'])) {
      continue;
    }
    $chado_table = $field['settings']['chado_table'];
    $chado_column = $field['settings']['chado_column'];
    $base_table = $field['settings']['base_table'];

    // Iterate through the field's items. Fields with cardinality ($delta) > 1
    // are multi-valued.
    $items = field_get_items($entity_type, $entity, $field_name);
    $temp = array();
    foreach ($items as $delta => $item) {

      // A field may have multiple items. The field can use items
      // indexed with "chado-" to represent values that should map directly
      // to chado tables and fields.
      foreach ($item as $item_name => $value) {
        $matches = array();
        if (preg_match('/^chado-(.*?)__(.*?)$/', $item_name, $matches)) {
          $table_name = $matches[1];
          $column_name = $matches[2];
          // If this field belongs to the base table then we just add
          // those values in... there's no delta.
          if ($table_name == $base_table) {
            $base_fields[$table_name][$column_name] = $value;
          }
          else {
            $temp[$table_name][$delta][$column_name] = $value;
          }
        }
      }

      // If there is no value set for the field using the
      // chado-[table_name]__[field name] naming schema then check if a 'value'
      // item is present and if so use that for the table column value.
      if ((!array_key_exists($chado_table, $temp) or
           !array_key_exists($delta, $temp[$chado_table]) or
           !array_key_exists($chado_column, $temp[$chado_table][$delta])) and
          array_key_exists('value', $items[$delta]) and
          !is_array($items[$delta]['value'])) {
        // If this field belongs to the base table then we just add
        // those values in... there's no delta.
        if ($base_table == $chado_table) {
          $base_fields[$chado_table][$chado_column] = $item['value'];
        }
        else {
          $temp[$chado_table][$delta][$chado_column] = $item['value'];
        }
      }
    }

    // Now merge the records for this field with the $new_fields array
    foreach ($temp as $table_name => $details) {
      foreach ($details as $delta => $list) {
        $all_fields[$table_name][] = $list;
      }
    }
  }

  $all_fields = array_merge($base_fields, $all_fields);
  return $all_fields;
}

/**
 * Recurses through a field's items breaking it into a nested array.
 */
function tripal_chado_field_storage_expand_field($item_name, $value) {

   $matches = array();
   if (preg_match('/^(.*?)--(.*?)$/', $item_name, $matches)) {
     $parent_item_name = $matches[1];
     $sub_item_name = $matches[2];
     $sub_item = tripal_chado_field_storage_expand_field($sub_item_name, $value);
     return array($parent_item_name => $sub_item);
   }
   else {
     return array($item_name => $value);
   }
}

/**
 * Implements hook_field_storage_query().
 */
function tripal_chado_field_storage_query($query) {
//print_r($query->fieldConditions);
  // The conditions and order bys are reorganized into a filters array for the
  // chado_select_record function()
  $filters = array();

  // Iterate through all the conditions and add to the filters array
  // a chado_select_record compatible set of filters.
  foreach ($query->fieldConditions as $index => $condition) {
    $field = $condition['field'];

    // Skip conditions that don't belong to this storage type.
    if ($field['storage']['type'] != 'field_chado_storage') {
      continue;
    }

    $column = $condition['column'];
    $value = $condition['value'];

    $field_type = $field['type'];
    $field_module = $field['module'];
    $settings = $field['settings'];

    // The Chado settings for a field are part of the instance and each bundle
    // can have the same field but with different Chado mappings. Therefore,
    // we need to iterate through the bundles to get the field instances.
    $bundles = $field['bundles'];
    foreach ($bundles['TripalEntity'] as $bundle_name) {

      // If there is a bundle filter for the entity and if this bundle is not in
      if (array_key_exists('bundle', $query->entityConditions)) {
        if (strtolower($query->entityConditions['bundle']['operator']) == 'in' and
            !array_key_exists($bundle_name, $query->entityConditions['bundle']['value'])) {
          continue;
        }
        else if ($query->entityConditions['bundle']['value'] != $bundle_name) {
          continue;
        }
      }

      // Get the Chado mapping for this instance.
      $instance = field_info_instance('TripalEntity', $field['field_name'], $bundle_name);
      $chado_table = $instance['settings']['chado_table'];
      $chado_column = $instance['settings']['chado_column'];

      // Set the value for this field search.
      $subfields = explode('.', $column);
      //print_r($subfields);
      if (count($subfields) > 1) {
        // Get the term for this field's column and replace the field_name with
        // the term.  We need to do this for the recursive function to work.
        // We must lowercase the term and underscore it because that's how we
        // can support case-insensitivity and lack of spacing such as for
        // web services.
        $subfield1 = tripal_get_chado_semweb_term($chado_table, $chado_column, array('return_object' => TRUE));
        $subfields[0] = strtolower(preg_replace('/ /', '_', $subfield1->name));
        $value = tripal_chado_field_storage_recurse_subfilters($chado_table, $subfields, $value);
        $value = array_shift($value);
      }
      else {
        $value = $condition['value'];
      }

      // Use the appropriate operator.
      $operator = $condition['operator'] ? $condition['operator'] : '=';
      switch ($operator) {
        case '=':
          $filters[$chado_table][$chado_column] = $value;
          break;
        case '>':
        case '>=':
        case '<':
        case '<=':
          $filters[$chado_table][$chado_column] = array(
            'op' => $operator,
            'data' => $value,
          );
          break;
        case '<>':
          $filters[$chado_table][$chado_column] = array(
            'op' => '<>',
            'data' => $value,
          );
          break;
        case 'CONTAINS':
          $filters[$chado_table][$chado_column] = array(
            'op' => 'LIKE',
            'data' => '%' . $value . '%',
          );
          break;
        case 'NOT':
          $filters[$chado_table][$chado_column] = array(
          'op' => 'NOT LIKE',
          'data' => '%' . $value . '%',
          );
          break;
        case 'STARTS WITH':
          $filters[$chado_table][$chado_column] = array(
            'op' => 'LIKE',
            'data' => $value . '%',
          );
          break;
        case 'NOT STARTS':
          $filters[$chado_table][$chado_column] = array(
          'op' => 'NOT LIKE',
          'data' => $value . '%',
          );
          break;
        case 'ENDS WITH':
          $filters[$chado_table][$chado_column] = array(
          'op' => 'LIKE',
          'data' => '%' . $value,
          );
          break;
        case 'NOT ENDS':
          $filters[$chado_table][$chado_column] = array(
          'op' => 'NOT LIKE',
          'data' => '%' . $value,
          );
          break;
        default:
          // unrecognized operation.
          break;
      }
    }
  } // end foreach ($query->fieldConditions as $index => $condition) {

  // Now get the list for sorting.
  foreach ($query->order as $index => $sort) {
    $field = $sort['specifier']['field'];

    // Skip sorts that don't belong to this storage type.
    if ($field['storage']['type'] != 'field_chado_storage') {
      continue;
    }

    $direction = $sort['direction'];

    $field_type = $field['type'];
    $field_module = $field['module'];
    $settings = $field['settings'];
    $chado_table = $settings['chado_table'];
    $chado_column = $settings['chado_column'];

    $sorting[$chado_table][$chado_column] = $direction;
  }
  //print_r($filters);

  // Iterate through the filters and perform the query.
  $entity_ids = array();
  foreach ($filters as $chado_table => $values) {
    //print_r($chado_table);
    //print_r($values);
    // First get the matching record IDs from the Chado table.
    $schema = chado_get_schema($chado_table);
    $pkey = $schema['primary key'][0];
    $results = chado_select_record($chado_table, array($pkey), $values);

    $record_ids = array();
    foreach ($results as $result) {
      $record_ids[] = $result->$pkey;
    }

    // Next look for matching IDs in the chado_entity table.
    $filter_ids = array();
    if (count($record_ids) > 0) {
      $select = db_select('chado_entity', 'CE');
      $select->join('tripal_entity', 'TE', 'TE.id = CE.entity_id');
      $select->fields('CE', array('entity_id'));
      $select->fields('TE', array('bundle'));
      $select->condition('record_id', $record_ids);
      // If a bundle is specified then make sure we match on the bundle.
      if (array_key_exists('bundle', $query->entityConditions)) {
        if (strtolower($query->entityConditions['bundle']['operator']) == 'in') {
          $select->condition('bundle', $query->entityConditions['bundle'], $operator);
        }
        else {
          $select->condition('bundle', $query->entityConditions['bundle']);
        }
      }

      $results = $select->execute();
      while ($result = $results->fetchObject()) {
        $entity_ids[] = array($result->entity_id, 0, $result->bundle);
      }
    }
  }

  $result = array(
    'TripalEntity' => array()
  );
  foreach ($entity_ids as $ids) {
    $result['TripalEntity'][$ids[0]] = entity_create_stub_entity('TripalEntity', $ids);
  }
  return $result;
}

/**
 *
 * @param $subfields
 * @param $value
 */
function tripal_chado_field_storage_recurse_subfilters($chado_table, $subfields, $value) {
   $sub_value = array();

   // Get the subvalue for this iteration
   $subfield = array_shift($subfields);

   // Get the cvterms mapped to this table.
   $columns = db_select('chado_semweb', 'CS')
     ->fields('CS', array('chado_column', 'cvterm_id'))
     ->condition('chado_table', $chado_table)
     ->execute();

   // Iterate through the columns and find the one with cvterm that matches
   // the subfield name.
   $chado_column = '';
   while($column = $columns->fetchObject()) {
     $cvterm_id = $column->cvterm_id;
     $cvterm = tripal_get_cvterm(array('cvterm_id' => $cvterm_id));
     // Convert the term name to lower-case and replace spaces with underscores
     // so we can perform case insensitive comparisions and ingore spacing.
     $term_name = strtolower(preg_replace('/ /', '_', $cvterm->name));
     if ($subfield == $term_name) {
       $chado_column = $column->chado_column;
     }
   }


   // If we have more subfields then this should be a foreign key and we should
   // recurse.
   if (count($subfields) > 0) {

    // Get the foreign keys for this Chado table.
     $schema = chado_get_schema($chado_table);
     $fkeys = $schema['foreign keys'];

     // Iterate through the FKs to find the one that matches this Chado field.
     foreach ($fkeys as $fk_table => $details) {
       foreach ($details['columns'] as $lkey => $rkey) {
         if ($lkey == $chado_column) {
           $sub_value = tripal_chado_field_storage_recurse_subfilters($fk_table, $subfields, $value);
           return array($chado_column => $sub_value);
         }
       }
     }
   }
   return array($chado_column => $value);
}