--- Module implementing the LuaRocks "new_version" command.
-- Utility function that writes a new rockspec, updating data from a previous one.
local new_version = {}

local util = require("luarocks.util")
local download = require("luarocks.download")
local fetch = require("luarocks.fetch")
local persist = require("luarocks.persist")
local fs = require("luarocks.fs")
local dir = require("luarocks.dir")
local type_rockspec = require("luarocks.type.rockspec")

function new_version.add_to_parser(parser)
   local cmd = parser:command("new_version", [[
This is a utility function that writes a new rockspec, updating data from a
previous one.

If a package name is given, it downloads the latest rockspec from the default
server. If a rockspec is given, it uses it instead. If no argument is given, it
looks for a rockspec same way 'luarocks make' does.

If the version number is not given and tag is passed using --tag, it is used as
the version, with 'v' removed from beginning.  Otherwise, it only increments the
revision number of the given (or downloaded) rockspec.

If a URL is given, it replaces the one from the old rockspec with the given URL.
If a URL is not given and a new version is given, it tries to guess the new URL
by replacing occurrences of the version number in the URL or tag; if the guessed
URL is invalid, the old URL is restored. It also tries to download the new URL
to determine the new MD5 checksum.

If a tag is given, it replaces the one from the old rockspec. If there is an old
tag but no new one passed, it is guessed in the same way URL is.

If a directory is not given, it defaults to the current directory.

WARNING: it writes the new rockspec to the given directory, overwriting the file
if it already exists.]], util.see_also())
      :summary("Auto-write a rockspec for a new version of a rock.")

   cmd:argument("rock", "Package name or rockspec.")
      :args("?")
   cmd:argument("new_version", "New version of the rock.")
      :args("?")
   cmd:argument("new_url", "New URL of the rock.")
      :args("?")

   cmd:option("--dir", "Output directory for the new rockspec.")
   cmd:option("--tag", "New SCM tag.")
end


local function try_replace(tbl, field, old, new)
   if not tbl[field] then
      return false
   end
   local old_field = tbl[field]
   local new_field = tbl[field]:gsub(old, new)
   if new_field ~= old_field then
      util.printout("Guessing new '"..field.."' field as "..new_field)
      tbl[field] = new_field
      return true
   end
   return false
end

-- Try to download source file using URL from a rockspec.
-- If it specified MD5, update it.
-- @return (true, false) if MD5 was not specified or it stayed same,
-- (true, true) if MD5 changed, (nil, string) on error.
local function check_url_and_update_md5(out_rs, invalid_is_error)
   local file, temp_dir = fetch.fetch_url_at_temp_dir(out_rs.source.url, "luarocks-new-version-"..out_rs.package)
   if not file then
      if invalid_is_error then
         return nil, "invalid URL - "..temp_dir
      end
      util.warning("invalid URL - "..temp_dir)
      return true, false
   end
   do
      local inferred_dir, found_dir = fetch.find_base_dir(file, temp_dir, out_rs.source.url, out_rs.source.dir)
      if not inferred_dir then
         return nil, found_dir
      end

      if found_dir and found_dir ~= inferred_dir then
         out_rs.source.dir = found_dir
      end
   end
   if file then
      if out_rs.source.md5 then
         util.printout("File successfully downloaded. Updating MD5 checksum...")
         local new_md5, err = fs.get_md5(file)
         if not new_md5 then
            return nil, err
         end
         local old_md5 = out_rs.source.md5
         out_rs.source.md5 = new_md5
         return true, new_md5 ~= old_md5
      else
         util.printout("File successfully downloaded.")
         return true, false
      end
   end
end

local function update_source_section(out_rs, url, tag, old_ver, new_ver)
   if tag then
      out_rs.source.tag = tag
   end
   if url then
      out_rs.source.url = url
      return check_url_and_update_md5(out_rs)
   end
   if new_ver == old_ver then
      return true
   end
   if out_rs.source.dir then
      try_replace(out_rs.source, "dir", old_ver, new_ver)
   end
   if out_rs.source.file then
      try_replace(out_rs.source, "file", old_ver, new_ver)
   end

   local old_url = out_rs.source.url
   if try_replace(out_rs.source, "url", old_ver, new_ver) then
      local ok, md5_changed = check_url_and_update_md5(out_rs, true)
      if ok then
         return ok, md5_changed
      end
      out_rs.source.url = old_url
   end
   if tag or try_replace(out_rs.source, "tag", old_ver, new_ver) then
      return true
   end
   -- Couldn't replace anything significant, use the old URL.
   local ok, md5_changed = check_url_and_update_md5(out_rs)
   if not ok then
      return nil, md5_changed
   end
   if md5_changed then
      util.warning("URL is the same, but MD5 has changed. Old rockspec is broken.")
   end
   return true
end

function new_version.command(args)
   if not args.rock then
      local err
      args.rock, err = util.get_default_rockspec()
      if not args.rock then
         return nil, err
      end
   end

   local filename, err
   if args.rock:match("rockspec$") then
      filename, err = fetch.fetch_url(args.rock)
      if not filename then
         return nil, err
      end
   else
      filename, err = download.download("rockspec", args.rock:lower())
      if not filename then
         return nil, err
      end
   end

   local valid_rs, err = fetch.load_rockspec(filename)
   if not valid_rs then
      return nil, err
   end

   local old_ver, old_rev = valid_rs.version:match("(.*)%-(%d+)$")
   local new_ver, new_rev

   if args.tag and not args.new_version then
      args.new_version = args.tag:gsub("^v", "")
   end

   local out_dir
   if args.dir then
      out_dir = dir.normalize(args.dir)
   end

   if args.new_version then
      new_ver, new_rev = args.new_version:match("(.*)%-(%d+)$")
      new_rev = tonumber(new_rev)
      if not new_rev then
         new_ver = args.new_version
         new_rev = 1
      end
   else
      new_ver = old_ver
      new_rev = tonumber(old_rev) + 1
   end
   local new_rockver = new_ver:gsub("-", "")

   local out_rs, err = persist.load_into_table(filename)
   local out_name = out_rs.package:lower()
   out_rs.version = new_rockver.."-"..new_rev

   local ok, err = update_source_section(out_rs, args.new_url, args.tag, old_ver, new_ver)
   if not ok then return nil, err end

   if out_rs.build and out_rs.build.type == "module" then
      out_rs.build.type = "builtin"
   end

   local out_filename = out_name.."-"..new_rockver.."-"..new_rev..".rockspec"
   if out_dir then
      out_filename = dir.path(out_dir, out_filename)
      fs.make_dir(out_dir)
   end
   persist.save_from_table(out_filename, out_rs, type_rockspec.order)

   util.printout("Wrote "..out_filename)

   local valid_out_rs, err = fetch.load_local_rockspec(out_filename)
   if not valid_out_rs then
      return nil, "Failed loading generated rockspec: "..err
   end

   return true
end

return new_version