-- Helper Functions
function file_exists(path)
  local attr = lighty.stat(path)
  if (attr and attr["is_file"]) then
      return true
   else
      return false
  end
end

function removePrefix(str, prefix)
  return str:sub(1,#prefix+1) == prefix .. "/" and str:sub(#prefix+2)
end

function string.starts(x,y)
  return string.sub(x,1,string.len(y)) == y
end


-- Set for subdirectory drupal installs
local prefix = ''

-- If this is not an existing file
if (not file_exists(lighty.env["physical.path"]))  then

  -- Set Drupal Expires Headers
  lighty.header["Expires"] = "Sun, 19 Nov 1978 05:00:00 GMT"
  lighty.header["Cache-Control"] = "no-store, no-cache, must-revalidate, post-check=0, pre-check=0"

  -- Set local variables
  local FINAL_PATH = "empty"
  local request_uri = removePrefix(lighty.env["uri.path"], prefix) -- none should be set to '/'
  local request_query = lighty.env["uri.query"] or ""

  -- Set 1st filter (anon+GET) to qualify boost caching
  local SERVE_CACHED_FLAG = (string.find((lighty.request["Cookie"] or "NOCOOKIE"), "DRUPAL_UID") == nil) and (lighty.env["request.method"] == "GET")
  -- Set 2nd filter to qualify boosted paths
  local RESTRICTED_PATHS = (string.starts(request_uri,"/user")) or (string.starts(request_uri,"/cache")) or (string.starts(request_uri,"/admin")) or (string.starts(request_uri,"/openid")) or (string.starts(request_uri,"/node/add"))  

  -- If qualifies for boost caching
  if (SERVE_CACHED_FLAG == true and RESTRICTED_PATHS == false) then 

    -- Build filename based on URL for cached pages
    local boost_path_normal = lighty.env["physical.doc-root"] .. "/cache/normal/" .. lighty.request["Host"] .. request_uri .. "_" .. request_query
    -- Build filename based on URL for cached css/js
    local boost_path_perm = lighty.env["physical.doc-root"] .. "/cache/perm/" .. lighty.request["Host"] .. request_uri .. "_" 

   -- Set Final Path & Content-Type if this file exists.
    if (file_exists(boost_path_perm .. ".css")) then
      FINAL_PATH = boost_path_perm .. ".css"
      lighty.header["Content-Type"] = "text/css"
    end
    if (file_exists(boost_path_perm .. ".js")) then
      FINAL_PATH = boost_path_perm .. ".js"
      lighty.header["Content-Type"] = "text/javascript"
    end
    if (file_exists(boost_path_normal .. ".html")) then
      FINAL_PATH = boost_path_normal .. ".html"
      lighty.header["Content-Type"] = "text/html"
    end
    if (file_exists(boost_path_normal .. ".xml")) then
      FINAL_PATH = boost_path_normal .. ".xml"
      lighty.header["Content-Type"] = "text/xml"
    end
    if (file_exists(boost_path_normal .. ".json")) then
      FINAL_PATH = boost_path_normal .. ".json"
      lighty.header["Content-Type"] = "text/javascript"
    end
  end

  -- URL not in boost cache, send it to drupal
  if (FINAL_PATH == "empty") then 
    if request_uri then
      lighty.env["uri.path"] = prefix .. "/index.php"
      lighty.env["uri.query"] = request_query .. (request_query ~= "" and "&" or "") .. "q=" .. request_uri
      lighty.env["physical.rel-path"] = lighty.env["uri.path"]
      lighty.env["request.orig-uri"]  = lighty.env["request.uri"]
      FINAL_PATH = lighty.env["physical.doc-root"] .. lighty.env["physical.rel-path"]
    end
  end

  -- Do it
  lighty.env["physical.path"] = FINAL_PATH
end