local rockspecs = {}
   
local cfg = require("luarocks.core.cfg")
local dir = require("luarocks.dir")
local path = require("luarocks.path")
local queries = require("luarocks.queries")
local type_rockspec = require("luarocks.type.rockspec")
local util = require("luarocks.core.util")
local vers = require("luarocks.core.vers")

local rockspec_mt = {}

rockspec_mt.__index = rockspec_mt

function rockspec_mt.type()
   return "rockspec"
end

--- Perform platform-specific overrides on a table.
-- Overrides values of table with the contents of the appropriate
-- subset of its "platforms" field. The "platforms" field should
-- be a table containing subtables keyed with strings representing
-- platform names. Names that match the contents of the global
-- detected platforms setting are used. For example, if
-- platform "unix" is detected, then the fields of
-- tbl.platforms.unix will overwrite those of tbl with the same
-- names. For table values, the operation is performed recursively
-- (tbl.platforms.foo.x.y.z overrides tbl.x.y.z; other contents of
-- tbl.x are preserved).
-- @param tbl table or nil: Table which may contain a "platforms" field;
-- if it doesn't (or if nil is passed), this function does nothing.
local function platform_overrides(tbl)
   assert(type(tbl) == "table" or not tbl)
   
   if not tbl then return end
   
   if tbl.platforms then
      for platform in cfg.each_platform() do
         local platform_tbl = tbl.platforms[platform]
         if platform_tbl then
            util.deep_merge(tbl, platform_tbl)
         end
      end
   end
   tbl.platforms = nil
end

local function convert_dependencies(rockspec, key)
   if rockspec[key] then
      for i = 1, #rockspec[key] do
         local parsed, err = queries.from_dep_string(rockspec[key][i])
         if not parsed then
            return nil, "Parse error processing dependency '"..rockspec[key][i].."': "..tostring(err)
         end
         rockspec[key][i] = parsed
      end
   else
      rockspec[key] = {}
   end
   return true
end

--- Set up path-related variables for a given rock.
-- Create a "variables" table in the rockspec table, containing
-- adjusted variables according to the configuration file.
-- @param rockspec table: The rockspec table.
local function configure_paths(rockspec)
   local vars = {}
   for k,v in pairs(cfg.variables) do
      vars[k] = v
   end
   local name, version = rockspec.name, rockspec.version
   vars.PREFIX = path.install_dir(name, version)
   vars.LUADIR = path.lua_dir(name, version)
   vars.LIBDIR = path.lib_dir(name, version)
   vars.CONFDIR = path.conf_dir(name, version)
   vars.BINDIR = path.bin_dir(name, version)
   vars.DOCDIR = path.doc_dir(name, version)
   rockspec.variables = vars
end

function rockspecs.from_persisted_table(filename, rockspec, globals, quick)
   assert(type(rockspec) == "table")
   assert(type(globals) == "table" or globals == nil)
   assert(type(filename) == "string")
   assert(type(quick) == "boolean" or quick == nil)

   if rockspec.rockspec_format then
      if vers.compare_versions(rockspec.rockspec_format, type_rockspec.rockspec_format) then
         return nil, "Rockspec format "..rockspec.rockspec_format.." is not supported, please upgrade LuaRocks."
      end
   end

   if not quick then
      local ok, err = type_rockspec.check(rockspec, globals or {})
      if not ok then
         return nil, err
      end
   end

   --- Check if rockspec format version satisfies version requirement.
   -- @param rockspec table: The rockspec table.
   -- @param version string: required version.
   -- @return boolean: true if rockspec format matches version or is newer, false otherwise.
   do
      local parsed_format = vers.parse_version(rockspec.rockspec_format or "1.0")
      rockspec.format_is_at_least = function(self, version)
         return parsed_format >= vers.parse_version(version)
      end
   end

   platform_overrides(rockspec.build)
   platform_overrides(rockspec.dependencies)
   platform_overrides(rockspec.build_dependencies)
   platform_overrides(rockspec.test_dependencies)
   platform_overrides(rockspec.external_dependencies)
   platform_overrides(rockspec.source)
   platform_overrides(rockspec.hooks)
   platform_overrides(rockspec.test)

   rockspec.name = rockspec.package:lower()

   local protocol, pathname = dir.split_url(rockspec.source.url)
   if dir.is_basic_protocol(protocol) then
      rockspec.source.file = rockspec.source.file or dir.base_name(rockspec.source.url)
   end
   rockspec.source.protocol, rockspec.source.pathname = protocol, pathname

   -- Temporary compatibility
   if rockspec.source.cvs_module then rockspec.source.module = rockspec.source.cvs_module end
   if rockspec.source.cvs_tag then rockspec.source.tag = rockspec.source.cvs_tag end

   rockspec.local_abs_filename = filename
   local filebase = rockspec.source.file or rockspec.source.url
   local base = dir.deduce_base_dir(filebase)
   rockspec.source.dir_set = rockspec.source.dir ~= nil
   rockspec.source.dir = rockspec.source.dir
                      or rockspec.source.module
                      or ( (filebase:match("%.lua$") or filebase:match("%.c$"))
                           and (rockspec:format_is_at_least("3.0")
                                and (dir.is_basic_protocol(protocol) and "." or base)
                                or  ".") )
                      or base

   rockspec.rocks_provided = (rockspec:format_is_at_least("3.0")
                              and cfg.rocks_provided_3_0
                              or  cfg.rocks_provided)

   for _, key in ipairs({"dependencies", "build_dependencies", "test_dependencies"}) do
      local ok, err = convert_dependencies(rockspec, key)
      if not ok then
         return nil, err
      end
   end

   if not quick then
      configure_paths(rockspec)
   end

   return setmetatable(rockspec, rockspec_mt)
end

return rockspecs