--- LuaRocks-specific path handling functions.
-- All paths are configured in this module, making it a single
-- point where the layout of the local installation is defined in LuaRocks.
module("luarocks.path", package.seeall)

local dir = require("luarocks.dir")
local cfg = require("luarocks.cfg")
local util = require("luarocks.util")

help_summary = "Return the currently configured package path."
help_arguments = ""
help = [[
Returns the package path currently configured for this installation
of LuaRocks, formatted as shell commands to update LUA_PATH and
LUA_CPATH. (On Unix systems, you may run: eval `luarocks path`)
]]

--- Infer rockspec filename from a rock filename.
-- @param rock_name string: Pathname of a rock file.
-- @return string: Filename of the rockspec, without path.
function rockspec_name_from_rock(rock_name)
   assert(type(rock_name) == "string")
   local base_name = dir.base_name(rock_name)
   return base_name:match("(.*)%.[^.]*.rock") .. ".rockspec"
end

function rocks_dir(tree)
   if type(tree) == "string" then
      return dir.path(tree, "lib", "luarocks", "rocks")
   else
      assert(type(tree) == "table")
      return tree.rocks_dir or dir.path(tree.root, "lib", "luarocks", "rocks")
   end
end

function root_dir(rocks_dir)
   assert(type(rocks_dir) == "string")
   
   local suffix = dir.path("lib", "luarocks", "rocks")
   return rocks_dir:match("(.*)" .. suffix .. "$")
end

function deploy_bin_dir(tree)
   if type(tree) == "string" then
      return dir.path(tree, "bin")
   else
      assert(type(tree) == "table")
      return tree.bin_dir or dir.path(tree.root, "bin")
   end
end

function deploy_lua_dir(tree)
   if type(tree) == "string" then
      return dir.path(tree, cfg.lua_modules_path)
   else
      assert(type(tree) == "table")
      return tree.lua_dir or dir.path(tree.root, cfg.lua_modules_path)
   end
end

function deploy_lib_dir(tree)
   if type(tree) == "string" then
      return dir.path(tree, cfg.lib_modules_path)
   else
      assert(type(tree) == "table")
      return tree.lib_dir or dir.path(tree.root, cfg.lib_modules_path)
   end
end

function manifest_file(tree)
   if type(tree) == "string" then
      return dir.path(tree, "lib", "luarocks", "rocks", "manifest")
   else
      assert(type(tree) == "table")
      return (tree.rocks_dir and dir.path(tree.rocks_dir, "manifest")) or dir.path(tree.root, "lib", "luarocks", "rocks", "manifest")
   end
end

--- Get the directory for all versions of a package in a tree.
-- @param name string: The package name. 
-- @return string: The resulting path -- does not guarantee that
-- @param tree string or nil: If given, specifies the local tree to use.
-- the package (and by extension, the path) exists.
function versions_dir(name, tree)
   assert(type(name) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name)
end

--- Get the local installation directory (prefix) for a package.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the path) exists.
function install_dir(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version)
end

--- Get the local filename of the rockspec of an installed rock.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the file) exists.
function rockspec_file(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version, name.."-"..version..".rockspec")
end

--- Get the local filename of the rock_manifest file of an installed rock.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the file) exists.
function rock_manifest_file(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version, "rock_manifest")
end

--- Get the local installation directory for C libraries of a package.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the path) exists.
function lib_dir(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version, "lib")
end

--- Get the local installation directory for Lua modules of a package.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the path) exists.
function lua_dir(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version, "lua")
end

--- Get the local installation directory for documentation of a package.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the path) exists.
function doc_dir(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version, "doc")
end

--- Get the local installation directory for configuration files of a package.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the path) exists.
function conf_dir(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version, "conf")
end

--- Get the local installation directory for command-line scripts
-- of a package.
-- @param name string: The package name. 
-- @param version string: The package version.
-- @param tree string or nil: If given, specifies the local tree to use.
-- @return string: The resulting path -- does not guarantee that
-- the package (and by extension, the path) exists.
function bin_dir(name, version, tree)
   assert(type(name) == "string")
   assert(type(version) == "string")
   tree = tree or cfg.root_dir
   return dir.path(rocks_dir(tree), name, version, "bin")
end

--- Extract name, version and arch of a rock filename,
-- or name, version and "rockspec" from a rockspec name.
-- @param file_name string: pathname of a rock or rockspec
-- @return (string, string, string) or nil: name, version and arch
-- or nil if name could not be parsed
function parse_name(file_name)
   assert(type(file_name) == "string")
   if file_name:match("%.rock$") then
      return dir.base_name(file_name):match("(.*)-([^-]+-%d+)%.([^.]+)%.rock$")
   else
      return dir.base_name(file_name):match("(.*)-([^-]+-%d+)%.(rockspec)")
   end
end

--- Make a rockspec or rock URL.
-- @param pathname string: Base URL or pathname.
-- @param name string: Package name.
-- @param version string: Package version.
-- @param arch string: Architecture identifier, or "rockspec" or "installed".
-- @return string: A URL or pathname following LuaRocks naming conventions.
function make_url(pathname, name, version, arch)
   assert(type(pathname) == "string")
   assert(type(name) == "string")
   assert(type(version) == "string")
   assert(type(arch) == "string")

   local filename = name.."-"..version
   if arch == "installed" then
      filename = dir.path(name, version, filename..".rockspec")
   elseif arch == "rockspec" then
      filename = filename..".rockspec"
   else
      filename = filename.."."..arch..".rock"
   end
   return dir.path(pathname, filename)
end

--- Convert a pathname to a module identifier.
-- In Unix, for example, a path "foo/bar/baz.lua" is converted to
-- "foo.bar.baz"; "bla/init.lua" returns "bla"; "foo.so" returns "foo".
-- @param file string: Pathname of module
-- @return string: The module identifier, or nil if given path is
-- not a conformant module path (the function does not check if the
-- path actually exists).
function path_to_module(file)
   assert(type(file) == "string")

   local name = file:match("(.*)%."..cfg.lua_extension.."$")
   if name then
      name = name:gsub(dir.separator, ".")
      local init = name:match("(.*)%.init$")
      if init then
         name = init
      end
   else
      name = file:match("(.*)%."..cfg.lib_extension.."$")
      if name then
         name = name:gsub(dir.separator, ".")
      end
   end
   if not name then name = file end
   name = name:gsub("^%.+", ""):gsub("%.+$", "")
   return name
end

--- Obtain the directory name where a module should be stored.
-- For example, on Unix, "foo.bar.baz" will return "foo/bar".
-- @param mod string: A module name in Lua dot-separated format.
-- @return string: A directory name using the platform's separator.
function module_to_path(mod)
   assert(type(mod) == "string")
   return (mod:gsub("[^.]*$", ""):gsub("%.", dir.separator))
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.
function configure_paths(rockspec)
   assert(type(rockspec) == "table")
   local vars = {}
   for k,v in pairs(cfg.variables) do
      vars[k] = v
   end
   local name, version = rockspec.name, rockspec.version
   vars.PREFIX = install_dir(name, version)
   vars.LUADIR = lua_dir(name, version)
   vars.LIBDIR = lib_dir(name, version)
   vars.CONFDIR = conf_dir(name, version)
   vars.BINDIR = bin_dir(name, version)
   vars.DOCDIR = doc_dir(name, version)
   rockspec.variables = vars
end

function versioned_name(file, prefix, name, version)
   assert(type(file) == "string")
   assert(type(name) == "string")
   assert(type(version) == "string")

   local rest = file:sub(#prefix+1):gsub("^/*", "")
   local name_version = (name.."_"..version):gsub("%-", "_"):gsub("%.", "_")
   return dir.path(prefix, name_version.."-"..rest)
end

function use_tree(tree)
   cfg.root_dir = tree
   cfg.rocks_dir = rocks_dir(tree)
   cfg.deploy_bin_dir = deploy_bin_dir(tree)
   cfg.deploy_lua_dir = deploy_lua_dir(tree)
   cfg.deploy_lib_dir = deploy_lib_dir(tree)
end

--- Driver function for "path" command.
-- @return boolean This function always succeeds.
function run(...)
   util.printout(cfg.export_lua_path:format(package.path))
   util.printout(cfg.export_lua_cpath:format(package.cpath))
   return true
end