initial commit

1 files changed, 688 insertions, 0 deletions

diff --git a/dependency.inc b/dependency.inc
new file mode 100755
index 0000000..a76d428
--- /dev/null
+++ b/dependency.inc
@@ -0,0 +1,688 @@
+<?php
+// $Id$
+
+function upload_dependency_form($form_state)
+{
+  global $user;
+
+  /************************ start approve book details ************************/
+  $proposal_q = db_query("SELECT * FROM {textbook_companion_proposal} WHERE uid = %d ORDER BY id DESC LIMIT 1", $user->uid);
+  $proposal_data = db_fetch_object($proposal_q);
+  if (!$proposal_data)
+  {
+    drupal_set_message("Please submit a " . l('proposal', 'proposal') . ".", 'error');
+    drupal_goto('');
+  }
+  if ($proposal_data->proposal_status  != 1 && $proposal_data->proposal_status  != 4)
+  {
+    switch ($proposal_data->proposal_status )
+    {
+    case 0:
+      drupal_set_message(t('We have already received your proposal. We will get back to you soon.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    case 2:
+      drupal_set_message(t('Your proposal has been dis-approved. Please create another proposal ' . l('here', 'proposal') . '.'), 'error');
+      drupal_goto('');
+      return;
+      break;
+    case 3:
+      drupal_set_message(t('Congratulations! You have completed your last book proposal. You have to create another proposal ' . l('here', 'proposal') . '.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    default:
+       drupal_set_message(t('Invalid proposal state. Please contact site administrator for further information.'), 'error');
+       drupal_goto('');
+       return;
+       break;
+    }
+  }
+
+  $preference_q = db_query("SELECT * FROM {textbook_companion_preference} WHERE proposal_id = %d AND approval_status = 1 LIMIT 1", $proposal_data->id);
+  $preference_data = db_fetch_object($preference_q);
+  if (!$preference_data)
+  {
+    drupal_set_message(t('Invalid Book Preference status. Please contact site administrator for further information.'), 'error');
+    drupal_goto('');
+    return;
+  }
+  /************************ end approve book details **************************/
+
+  $form['#attributes'] = array('enctype' => "multipart/form-data");
+
+  $form['book_details']['book'] = array(
+    '#type' => 'item',
+    '#value' => $preference_data->book,
+    '#title' => t('Title of the Book'),
+  );
+  $form['contributor_name'] = array(
+    '#type' => 'item',
+    '#value' => $proposal_data->full_name,
+    '#title' => t('Contributor Name'),
+  );
+
+  $form['existing_depfile'] = array(
+    '#type' => 'item',
+    '#value' => _list_existing_dependency($preference_data->id),
+    '#title' => t('List of existing dependency files for this book'),
+  );
+
+  $form['depfile'] = array(
+    '#type' => 'fieldset',
+    '#title' => t('Upload Dependency Files'),
+    '#collapsible' => FALSE,
+    '#collapsed' => FALSE,
+  );
+  $form['depfile']['depfile1'] = array(
+      '#type' => 'file',
+      '#title' => t('Upload dependency file'),
+      '#description' => t("Allowed file extensions : ") . variable_get('textbook_companion_dependency_extensions', ''),
+  );
+  $form['depfile']['depfile1_caption'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Caption for dependency file'),
+      '#size' => 15,
+      '#maxlength' => 100,
+      '#required' => TRUE,
+  );
+  $form['depfile']['depfile1_description'] = array(
+      '#type' => 'textarea',
+      '#title' => t('Brief Description of the dependency file'),
+  );
+
+  $form['submit'] = array(
+    '#type' => 'submit',
+    '#value' => t('Submit')
+  );
+
+  $form['cancel'] = array(
+    '#type' => 'markup',
+    '#value' => l(t('Back'), 'textbook_companion/code/upload'),
+  );
+  return $form;
+}
+
+function upload_dependency_form_validate($form, &$form_state)
+{
+  global $user;
+
+  /* get approved book details */
+  $book_q = db_query("SELECT pro.id as pro_id, pre.id as pre_id, pre.book as pre_book, pro.full_name as pro_full_name FROM {textbook_companion_proposal} pro JOIN {textbook_companion_preference} pre ON pro.id = pre.proposal_id WHERE pro.proposal_status = 1 AND pre.approval_status = 1 AND pro.uid = %d", $user->uid);
+  $book_data = db_fetch_object($book_q);
+
+  if (isset($_FILES['files']))
+  {
+    /* check for valid filename extensions */  
+    $allowed_extensions = explode(',' , variable_get('textbook_companion_dependency_extensions', ''));
+    foreach ($_FILES['files']['name'] as $file_form_name => $file_name)
+    {
+      if ($file_name)
+      {
+         $temp_extension = end(explode('.', strtolower($_FILES['files']['name'][$file_form_name])));
+         if (!in_array($temp_extension, $allowed_extensions))
+           form_set_error($file_form_name, t('Only ' . variable_get('textbook_companion_dependency_extensions', '') . ' extensions can be uploaded.'));
+         if ($_FILES['files']['size'][$file_form_name] <= 0)
+           form_set_error($file_form_name, t('File size cannot be zero.'));
+
+         /* check if file already exists */
+         $dep_exists_data = db_fetch_object(db_query("SELECT * FROM {textbook_companion_dependency_files} WHERE filename = '%s'", $_FILES['files']['name'][$file_form_name]));
+         if ($dep_exists_data)
+           form_set_error($file_form_name, t('Dependency file with the same name has already been uploaded in this or some other book. Please rename the file and try again.'));
+
+         /* check if valid file name */
+         if (!textbook_companion_check_valid_filename($_FILES['files']['name'][$file_form_name]))
+           form_set_error($file_form_name, t('Invalid file name specified. Only alphabets, numbers and underscore is allowed as a valid filename.'));
+      }
+    }
+  }
+}
+
+function upload_dependency_form_submit($form, &$form_state) {
+  global $user;
+
+  $root_path = textbook_companion_path();
+
+  /* get approved book details */
+  $proposal_q = db_query("SELECT * FROM {textbook_companion_proposal} WHERE uid = %d ORDER BY id DESC LIMIT 1", $user->uid);
+  $proposal_data = db_fetch_object($proposal_q);
+  if (!$proposal_data)
+  {
+    drupal_set_message("Please submit a " . l('proposal', 'proposal') . ".", 'error');
+    drupal_goto('');
+  }
+  if ($proposal_data->proposal_status  != 1 && $proposal_data->proposal_status  != 4)
+  {
+    switch ($proposal_data->proposal_status )
+    {
+    case 0:
+      drupal_set_message(t('We have already received your proposal. We will get back to you soon.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    case 2:
+      drupal_set_message(t('Your proposal has been dis-approved. Please create another proposal ' . l('here', 'proposal') . '.'), 'error');
+      drupal_goto('');
+      return;
+      break;
+    case 3:
+      drupal_set_message(t('Congratulations! You have completed your last book proposal. You have to create another proposal ' . l('here', 'proposal') . '.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    default:
+       drupal_set_message(t('Invalid proposal state. Please contact site administrator for further information.'), 'error');
+       drupal_goto('');
+       return;
+       break;
+    }
+  }
+
+  $preference_q = db_query("SELECT * FROM {textbook_companion_preference} WHERE proposal_id = %d AND approval_status = 1 LIMIT 1", $proposal_data->id);
+  $preference_data = db_fetch_object($preference_q);
+  if (!$preference_data)
+  {
+    drupal_set_message(t('Invalid Book Preference status. Please contact site administrator for further information.'), 'error');
+    drupal_goto('');
+    return;
+  }
+
+  $preference_id = $preference_data->id;
+
+  $dest_path = $preference_id . '/';
+  if (!is_dir($root_path . $dest_path))
+    mkdir($root_path . $dest_path);
+
+  $dest_path .= 'DEPENDENCIES' . '/';
+  if (!is_dir($root_path . $dest_path))
+    mkdir($root_path . $dest_path);
+
+  /* uploading dependencies */
+  $file_upload_counter = 0;
+  $dependency_ids = array();
+  $dependency_names = array();
+
+  foreach ($_FILES['files']['name'] as $file_form_name => $file_name)
+  {
+    if ($file_name)
+    {
+      /* uploading file */
+      if (move_uploaded_file($_FILES['files']['tmp_name'][$file_form_name], $root_path . $dest_path . $_FILES['files']['name'][$file_form_name]))
+      {
+        /* for uploaded files making an entry in the database */
+        db_query("INSERT INTO {textbook_companion_dependency_files} (preference_id, filename, filepath, filemime, filesize, caption, description, timestamp)
+          VALUES (%d, '%s', '%s', '%s', %d, '%s', '%s', %d)",
+          $preference_id,
+          $_FILES['files']['name'][$file_form_name],
+          $dest_path . $_FILES['files']['name'][$file_form_name],
+          $_FILES['files']['type'][$file_form_name],
+          $_FILES['files']['size'][$file_form_name],
+          $form_state['values'][$file_form_name . '_caption'],
+          $form_state['values'][$file_form_name . '_description'],
+          time()
+          );
+        drupal_set_message($file_name . ' uploaded successfully.', 'status');
+        $dependency_ids[] = db_last_insert_id('textbook_companion_dependency_files', 'id');
+        $dependency_names[] =  $_FILES['files']['name'][$file_form_name];
+        $file_upload_counter++;
+      } else {
+        drupal_set_message('Error uploading dependency : ' . $dest_path . '/' . $_FILES['files']['name'][$file_form_name], 'error');
+      }
+    }
+  }
+
+  if ($file_upload_counter > 0)
+  {
+    drupal_set_message('Dependencies uploaded successfully.', 'status');
+  
+    /* sending email */
+    $param['dependency_uploaded']['user_id'] = $user->uid;
+    $param['dependency_uploaded']['dependency_names'] = $dependency_names;
+
+    $email_to = $user->mail;
+    if (!drupal_mail('textbook_companion', 'dependency_uploaded', $email_to, language_default(), $param, variable_get('textbook_companion_from_email', NULL), TRUE))
+      drupal_set_message('Error sending email message.', 'error');
+  }
+
+  drupal_goto('textbook_companion/code/upload_dep');
+}
+
+function _list_existing_dependency($book_id)
+{
+  // $return_html = '<ul>';
+  $return_html = "";
+  $query = "SELECT * FROM textbook_companion_dependency_files WHERE preference_id = %d ORDER BY filename ASC";
+  $result = db_query($query, $book_id);
+
+  // $counter = 0;
+  // while ($row = db_fetch_object($query))
+  // {
+  //   $temp_caption = '';
+  //   if ($row->caption)
+  //     $temp_caption = ' (' . $row->caption . ')';
+  //   $return_html .= '<li>' . l($row->filename . $temp_caption, 'download/dependency/' . $row->id) . '</li>';
+  //   $counter++;
+  // }
+  // if ($counter == 0)
+  //   $return_html .= '<li>(None)</li>';
+  // $return_html .= '</ul>';
+
+  $headers = array(
+    "File", "Action",
+  );
+  $rows = array();
+  while($row = db_fetch_object($result)) {
+    $item = array(
+      l($row->filename . $temp_caption, 'download/dependency/' . $row->id),
+      l("Edit", "textbook_companion/code/edit_dep/{$row->id}") 
+      . " | " . l("Delete","textbook_companion/code/delete_dep/{$row->id}")
+    );
+    array_push($rows, $item);
+  }
+  $return_html .= theme("table", $headers, $rows);
+  return $return_html;
+}
+
+/******************** edit dependency section ********************/
+
+function edit_dependency_form($form_state, $dependency_id=0)
+{
+  global $user;
+
+  /************************ start approve book details ************************/
+  $proposal_q = db_query("SELECT * FROM {textbook_companion_proposal} WHERE uid = %d ORDER BY id DESC LIMIT 1", $user->uid);
+  $proposal_data = db_fetch_object($proposal_q);
+  if (!$proposal_data)
+  {
+    drupal_set_message("Please submit a " . l('proposal', 'proposal') . ".", 'error');
+    drupal_goto('');
+  }
+  if ($proposal_data->proposal_status  != 1 && $proposal_data->proposal_status  != 4)
+  {
+    switch ($proposal_data->proposal_status )
+    {
+    case 0:
+      drupal_set_message(t('We have already received your proposal. We will get back to you soon.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    case 2:
+      drupal_set_message(t('Your proposal has been dis-approved. Please create another proposal ' . l('here', 'proposal') . '.'), 'error');
+      drupal_goto('');
+      return;
+      break;
+    case 3:
+      drupal_set_message(t('Congratulations! You have completed your last book proposal. You have to create another proposal ' . l('here', 'proposal') . '.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    default:
+       drupal_set_message(t('Invalid proposal state. Please contact site administrator for further information.'), 'error');
+       drupal_goto('');
+       return;
+       break;
+    }
+  }
+
+  $preference_q = db_query("SELECT * FROM {textbook_companion_preference} WHERE proposal_id = %d AND approval_status = 1 LIMIT 1", $proposal_data->id);
+  $preference_data = db_fetch_object($preference_q);
+  if (!$preference_data)
+  {
+    drupal_set_message(t('Invalid Book Preference status. Please contact site administrator for further information.'), 'error');
+    drupal_goto('');
+    return;
+  }
+  /************************ end approve book details **************************/
+  /* fetching the default values */
+  $query = "
+    SELECT * FROM {textbook_companion_dependency_files}
+    WHERE id = {$dependency_id}
+  ";
+  $result = db_query($query);
+  $row = db_fetch_object($result);
+
+  $form['#attributes'] = array('enctype' => "multipart/form-data");
+
+  $form['depfile'] = array(
+    '#type' => 'fieldset',
+    '#title' => t('Upload New Dependency File'),
+    '#collapsible' => FALSE,
+    '#collapsed' => FALSE,
+  );
+  $form['depfile']['depfile1'] = array(
+      '#type' => 'file',
+      '#title' => t('Upload dependency file'),
+      '#description' => t("Allowed file extensions : ") . variable_get('textbook_companion_dependency_extensions', ''),
+  );
+  $form['depfile']['depfile1_caption'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Caption for dependency file'),
+      '#size' => 15,
+      '#maxlength' => 100,
+      '#required' => TRUE,
+      "#default_value" => $row->caption,
+  );
+  $form['depfile']['depfile1_description'] = array(
+      '#type' => 'textarea',
+      '#title' => t('Brief Description of the dependency file'),
+      "#default_value" => $row->description,
+  );
+
+  $form["dependency_id"] = array(
+    "#type" => "hidden",
+    "#value" => $dependency_id
+  );
+
+  $form['submit'] = array(
+    '#type' => 'submit',
+    '#value' => t('Submit')
+  );
+
+  $form['cancel'] = array(
+    '#type' => 'markup',
+    '#value' => l(t('Back'), 'textbook_companion/code/upload_dep'),
+  );
+  return $form;
+}
+
+function edit_dependency_form_validate($form, &$form_state)
+{
+  global $user;
+
+  if (isset($_FILES['files']))
+  {
+    /* check for valid filename extensions */  
+    $allowed_extensions = explode(',' , variable_get('textbook_companion_dependency_extensions', ''));
+    foreach ($_FILES['files']['name'] as $file_form_name => $file_name)
+    {
+      if ($file_name)
+      {
+         $temp_extension = end(explode('.', strtolower($_FILES['files']['name'][$file_form_name])));
+         if (!in_array($temp_extension, $allowed_extensions))
+           form_set_error($file_form_name, t('Only ' . variable_get('textbook_companion_dependency_extensions', '') . ' extensions can be uploaded.'));
+         if ($_FILES['files']['size'][$file_form_name] <= 0)
+           form_set_error($file_form_name, t('File size cannot be zero.'));
+
+        /* check if file already exists */
+         $dep_exists_data = db_fetch_object(
+           db_query(
+             "SELECT * FROM {textbook_companion_dependency_files} WHERE filename = '%s' AND id != %d",
+             $_FILES['files']['name'][$file_form_name],
+             $form_state["values"]["dependency_id"]
+           )
+         );
+
+        if ($dep_exists_data)
+          form_set_error($file_form_name, t('Dendency file with the same name has already been uploaded in this or some other book. Please rename the file and try again.'));
+
+         /* check if valid file name */
+         if (!textbook_companion_check_valid_filename($_FILES['files']['name'][$file_form_name]))
+           form_set_error($file_form_name, t('Invalid file name specified. Only alphabets, numbers and underscore is allowed as a valid filename.'));
+      }
+    }
+  }
+}
+
+function edit_dependency_form_submit($form, &$form_state) {
+  global $user;
+
+  $root_path = textbook_companion_path();
+
+  /* get approved book details */
+  $proposal_q = db_query("SELECT * FROM {textbook_companion_proposal} WHERE uid = %d ORDER BY id DESC LIMIT 1", $user->uid);
+  $proposal_data = db_fetch_object($proposal_q);
+  if (!$proposal_data)
+  {
+    drupal_set_message("Please submit a " . l('proposal', 'proposal') . ".", 'error');
+    drupal_goto('');
+  }
+  if ($proposal_data->proposal_status  != 1 && $proposal_data->proposal_status  != 4)
+  {
+    switch ($proposal_data->proposal_status )
+    {
+    case 0:
+      drupal_set_message(t('We have already received your proposal. We will get back to you soon.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    case 2:
+      drupal_set_message(t('Your proposal has been dis-approved. Please create another proposal ' . l('here', 'proposal') . '.'), 'error');
+      drupal_goto('');
+      return;
+      break;
+    case 3:
+      drupal_set_message(t('Congratulations! You have completed your last book proposal. You have to create another proposal ' . l('here', 'proposal') . '.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    default:
+       drupal_set_message(t('Invalid proposal state. Please contact site administrator for further information.'), 'error');
+       drupal_goto('');
+       return;
+       break;
+    }
+  }
+
+  $preference_q = db_query("SELECT * FROM {textbook_companion_preference} WHERE proposal_id = %d AND approval_status = 1 LIMIT 1", $proposal_data->id);
+  $preference_data = db_fetch_object($preference_q);
+  if (!$preference_data)
+  {
+    drupal_set_message(t('Invalid Book Preference status. Please contact site administrator for further information.'), 'error');
+    drupal_goto('');
+    return;
+  }
+
+  $preference_id = $preference_data->id;
+
+  $dest_path = $preference_id . '/';
+  if (!is_dir($root_path . $dest_path))
+    mkdir($root_path . $dest_path);
+
+  $dest_path .= 'DEPENDENCIES' . '/';
+  if (!is_dir($root_path . $dest_path))
+    mkdir($root_path . $dest_path);
+
+  /* uploading dependencies */
+  $file_upload_counter = 0;
+  $dependency_ids = array();
+  $dependency_names = array();
+
+  /* deleting old dependency file if the filename changed */
+  $query = "
+    SELECT * FROM textbook_companion_dependency_files 
+    WHERE id = %d
+  ";
+  $result = db_query($query, $form_state["values"]["dependency_id"]);
+  $row = db_fetch_object($result);
+  if($row->filename != $_FILES["files"]["name"][$file_form_name] && $_FILES["files"]["name"][$file_form_name]) {
+    unlink($root_path . $dest_path . $row->filename);
+  }
+
+  foreach ($_FILES['files']['name'] as $file_form_name => $file_name)
+  {
+    if ($file_name)
+    {
+      /* 
+       * uploading file 
+       * file will be overwritten if same name
+      */
+      if (move_uploaded_file($_FILES['files']['tmp_name'][$file_form_name], $root_path . $dest_path . $_FILES['files']['name'][$file_form_name]))
+      {
+        /* updating uploaded file entry in the database */
+        db_query(
+          "UPDATE {textbook_companion_dependency_files} SET
+          filename = '%s', filepath = '%s', filemime = '%s', filesize = %d,
+          caption = '%s', description = '%s', timestamp = %s
+          WHERE id = %d",
+          $_FILES['files']['name'][$file_form_name],
+          $dest_path . $_FILES['files']['name'][$file_form_name],
+          $_FILES['files']['type'][$file_form_name],
+          $_FILES['files']['size'][$file_form_name],
+          $form_state['values'][$file_form_name . '_caption'],
+          $form_state['values'][$file_form_name . '_description'],
+          time(),
+          $form_state["values"]["dependency_id"]
+        );
+      
+        drupal_set_message($file_name . ' uploaded successfully.', 'status');
+        $dependency_ids[] = db_last_insert_id('textbook_companion_dependency_files', 'id');
+        $dependency_names[] =  $_FILES['files']['name'][$file_form_name];
+        $file_upload_counter++;
+      } else {
+        drupal_set_message('Error uploading dependency : ' . $dest_path . '/' . $_FILES['files']['name'][$file_form_name], 'error');
+      }
+    }
+  }
+
+  if ($file_upload_counter > 0)
+  {
+    drupal_set_message('Dependencies uploaded successfully.', 'status');
+  
+    /* sending email */
+    $param['dependency_uploaded']['user_id'] = $user->uid;
+    $param['dependency_uploaded']['dependency_names'] = $dependency_names;
+
+    $email_to = $user->mail;
+    if (!drupal_mail('textbook_companion', 'dependency_uploaded', $email_to, language_default(), $param, variable_get('textbook_companion_from_email', NULL), TRUE))
+      drupal_set_message('Error sending email message.', 'error');
+  }
+
+  drupal_goto('textbook_companion/code/upload_dep');
+}
+
+function edit_dependency($dependency_id = 0) {
+  if($dependency_id){
+    $page_content = "";
+    $page_content .= drupal_get_form("edit_dependency_form", $dependency_id);
+    return $page_content;
+  } else {
+    drupal_goto("textbook_companion/code/upload_dep");
+  }
+}
+
+/******************** delete dependency section ********************/
+
+function delete_dependency($dependency_id = 0, $confirm = "") {
+  global $user;
+
+  /************************ start approve book details ************************/
+  $proposal_q = db_query("SELECT * FROM {textbook_companion_proposal} WHERE uid = %d ORDER BY id DESC LIMIT 1", $user->uid);
+  $proposal_data = db_fetch_object($proposal_q);
+  if (!$proposal_data)
+  {
+    drupal_set_message("Please submit a " . l('proposal', 'proposal') . ".", 'error');
+    drupal_goto('');
+  }
+  if ($proposal_data->proposal_status  != 1 && $proposal_data->proposal_status  != 4)
+  {
+    switch ($proposal_data->proposal_status )
+    {
+    case 0:
+      drupal_set_message(t('We have already received your proposal. We will get back to you soon.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    case 2:
+      drupal_set_message(t('Your proposal has been dis-approved. Please create another proposal ' . l('here', 'proposal') . '.'), 'error');
+      drupal_goto('');
+      return;
+      break;
+    case 3:
+      drupal_set_message(t('Congratulations! You have completed your last book proposal. You have to create another proposal ' . l('here', 'proposal') . '.'), 'status');
+      drupal_goto('');
+      return;
+      break;
+    default:
+       drupal_set_message(t('Invalid proposal state. Please contact site administrator for further information.'), 'error');
+       drupal_goto('');
+       return;
+       break;
+    }
+  }
+
+  $preference_q = db_query("SELECT * FROM {textbook_companion_preference} WHERE proposal_id = %d AND approval_status = 1 LIMIT 1", $proposal_data->id);
+  $preference_data = db_fetch_object($preference_q);
+  if (!$preference_data)
+  {
+    drupal_set_message(t('Invalid Book Preference status. Please contact site administrator for further information.'), 'error');
+    drupal_goto('');
+    return;
+  }
+  /************************ end approve book details **************************/
+  $page_content = "";
+  if($dependency_id && $confirm == "yes") {
+    /* removing the dependency file from filesystem */
+    $query = "
+      SELECT * FROM {textbook_companion_dependency_files}
+      WHERE id = {$dependency_id}
+    ";
+    $result = db_query($query);
+    $row = db_fetch_object($result);
+
+    if($preference_data->id == $row->preference_id) {
+      $root_path = textbook_companion_path();
+      $dest_path = $row->preference_id . '/';
+      $dest_path .= 'DEPENDENCIES' . '/';
+      unlink($root_path . $dest_path . $row->filename);
+
+      /* deleting entry in textbook_companion_dependency_files */
+      $query = "
+        DELETE FROM {textbook_companion_dependency_files}
+        WHERE id = {$dependency_id}
+        ";
+      db_query($query);
+
+      /* deleting entries from textbook_companion_example_dependency */
+      $query = "
+        DELETE FROM {textbook_companion_example_dependency}
+        WHERE dependency_id = {$dependency_id}
+        ";
+      db_query($query);
+
+      drupal_set_message("Dependency deleted successfully.");
+      drupal_goto("textbook_companion/code/upload_dep");
+    } else {
+      drupal_set_message("Cannot delete other users dependency.", "error");
+      drupal_goto("textbook_companion/code/upload_dep");
+    }
+  } else if($dependency_id) {
+    $query = "
+      SELECT * FROM {textbook_companion_dependency_files}
+      WHERE id = %d
+    ";
+    $result = db_query($query, $dependency_id);
+    $row = db_fetch_object($result);
+
+
+    if($preference_data->id == $row->preference_id) {
+      $page_content .= "Are you sure you want to delete this dependency?<br><br>";
+      $page_content .= "Dependency filename: <b>{$row->filename}</b><br><br>";
+
+      /* fetching the examples linked to this dependency */
+      $query = "
+        SELECT * FROM textbook_companion_example_dependency dep
+        LEFT JOIN textbook_companion_example exa ON exa.id = dep.example_id
+        WHERE dep.id = %d
+      ";
+      $result = db_query($query, $dependency_id);
+      $list = "";
+      while($row = db_fetch_object($result)) {
+        $list .= "<li>Example {$row->number}</li>";
+      }
+      if($list) {
+        $page_content .= "List of examples linking to this dependency are:";
+        $page_content .= "<ul>{$list}</ul>";
+      }
+      $page_content .= l("Delete dependency", "textbook_companion/code/delete_dep/{$dependency_id}/yes");
+      $page_content .= " | ";
+      $page_content .= l("Cancel", "textbook_companion/code/upload_dep");
+    } else {
+      drupal_set_message("Cannot delete other users dependency.", "error");
+      drupal_goto("textbook_companion/code/upload_dep");
+    }
+  } else {
+    drupal_goto("textbook_companion/code/upload_dep");
+  }
+  return $page_content;
+}