local api = {}

local cfg = require("luarocks.core.cfg")
local fs = require("luarocks.fs")
local dir = require("luarocks.dir")
local util = require("luarocks.util")
local persist = require("luarocks.persist")
local multipart = require("luarocks.upload.multipart")

local Api = {}

local function upload_config_file()
   local conf = cfg.which_config()
   if not conf.user.file then
      return nil
   end
   return (conf.user.file:gsub("/[^/]+$", "/upload_config.lua"))
end

function Api:load_config()
   local upload_conf = upload_config_file()
   if not upload_conf then return nil end
   local config, err = persist.load_into_table(upload_conf)
   return config
end

function Api:save_config()
   -- Test configuration before saving it.
   local res, err = self:raw_method("status")
   if not res then
      return nil, err
   end
   if res.errors then
      util.printerr("Server says: " .. tostring(res.errors[1]))
      return
   end
   local upload_conf = upload_config_file()
   if not upload_conf then return nil end
   local ok, err = fs.make_dir(dir.dir_name(upload_conf))
   if not ok then
      return nil, err
   end
   persist.save_from_table(upload_conf, self.config)
   fs.set_permissions(upload_conf, "read", "user")
end

function Api:check_version()
   if not self._server_tool_version then
      local tool_version = cfg.upload.tool_version
      local res, err = self:request(tostring(self.config.server) .. "/api/tool_version", {
        current = tool_version
      })
      if not res then
         return nil, err
      end
      if not res.version then
         return nil, "failed to fetch tool version"
      end
      self._server_tool_version = res.version
      if res.force_update then
         return nil, "Your upload client is too out of date to continue, please upgrade LuaRocks."
      end
      if res.version ~= tool_version then
         util.warning("your LuaRocks is out of date, consider upgrading.")
      end
   end
   return true
end

function Api:method(...)
   local res, err = self:raw_method(...)
   if not res then
      return nil, err
   end
   if res.errors then
      if res.errors[1] == "Invalid key" then
         return nil, res.errors[1] .. " (use the --api-key flag to change)"
      end
      local msg = table.concat(res.errors, ", ")
      return nil, "API Failed: " .. msg
   end
   return res
end

function Api:raw_method(path, ...)
   self:check_version()
   local url = tostring(self.config.server) .. "/api/" .. tostring(cfg.upload.api_version) .. "/" .. tostring(self.config.key) .. "/" .. tostring(path)
   return self:request(url, ...)
end

local function encode_query_string(t, sep)
   if sep == nil then
      sep = "&"
   end
   local i = 0
   local buf = { }
   for k, v in pairs(t) do
      if type(k) == "number" and type(v) == "table" then
         k, v = v[1], v[2]
      end
      buf[i + 1] = multipart.url_escape(k)
      buf[i + 2] = "="
      buf[i + 3] = multipart.url_escape(v)
      buf[i + 4] = sep
      i = i + 4
   end
   buf[i] = nil
   return table.concat(buf)
end

local function redact_api_url(url)
   url = tostring(url)
   return (url:gsub(".*/api/[^/]+/[^/]+", "")) or ""
end

local ltn12_ok, ltn12 = pcall(require, "ltn12")
if not ltn12_ok then -- If not using LuaSocket and/or LuaSec...

function Api:request(url, params, post_params)
   local vars = cfg.variables
   local json_ok, json = util.require_json()
   if not json_ok then return nil, "A JSON library is required for this command. "..json end
   
   if fs.which_tool("downloader") == "wget" then
      local curl_ok, err = fs.is_tool_available(vars.CURL, "curl")
      if not curl_ok then
         return nil, err
      end
   end

   if not self.config.key then
      return nil, "Must have API key before performing any actions."
   end
   if params and next(params) then
      url = url .. ("?" .. encode_query_string(params))
   end
   local method = "GET"
   local out 
   local tmpfile = fs.tmpname()
   if post_params then
      method = "POST"
      local curl_cmd = vars.CURL.." -f -k -L --silent --user-agent \""..cfg.user_agent.." via curl\" "
      for k,v in pairs(post_params) do
         local var = v
         if type(v) == "table" then
            var = "@"..v.fname
         end
         curl_cmd = curl_cmd .. "--form \""..k.."="..var.."\" "
      end
      if cfg.connection_timeout and cfg.connection_timeout > 0 then
        curl_cmd = curl_cmd .. "--connect-timeout "..tonumber(cfg.connection_timeout).." " 
      end
      local ok = fs.execute_string(curl_cmd..fs.Q(url).." -o "..fs.Q(tmpfile))
      if not ok then
         return nil, "API failure: " .. redact_api_url(url)
      end
   else
      local ok, err = fs.download(url, tmpfile)
      if not ok then
         return nil, "API failure: " .. tostring(err) .. " - " .. redact_api_url(url)
      end
   end

   local tmpfd = io.open(tmpfile)
   if not tmpfd then
      os.remove(tmpfile)
      return nil, "API failure reading temporary file - " .. redact_api_url(url)
   end
   out = tmpfd:read("*a")
   tmpfd:close()
   os.remove(tmpfile)

   if self.debug then
      util.printout("[" .. tostring(method) .. " via curl] " .. redact_api_url(url) .. " ... ")
   end

   return json.decode(out)
end

else -- use LuaSocket and LuaSec

local warned_luasec = false

function Api:request(url, params, post_params)
   local json_ok, json = util.require_json()
   if not json_ok then return nil, "A JSON library is required for this command. "..json end
   local server = tostring(self.config.server)
   local http_ok, http
   local via = "luasocket"
   if server:match("^https://") then
      http_ok, http = pcall(require, "ssl.https")
      if http_ok then
         via = "luasec"
      else
         if not warned_luasec then
            util.printerr("LuaSec is not available; using plain HTTP. Install 'luasec' to enable HTTPS.")
            warned_luasec = true
         end
         http_ok, http = pcall(require, "socket.http")
         url = url:gsub("^https", "http")
         via = "luasocket"
      end
   else
      http_ok, http = pcall(require, "socket.http")
   end
   if not http_ok then
      return nil, "Failed loading socket library!"
   end
   
   if not self.config.key then
      return nil, "Must have API key before performing any actions."
   end
   local body
   local headers = {}
   if params and next(params) then
      url = url .. ("?" .. encode_query_string(params))
   end
   if post_params then
      local boundary
      body, boundary = multipart.encode(post_params)
      headers["Content-length"] = #body
      headers["Content-type"] = "multipart/form-data; boundary=" .. tostring(boundary)
   end
   local method = post_params and "POST" or "GET"
   if self.debug then
      util.printout("[" .. tostring(method) .. " via "..via.."] " .. redact_api_url(url) .. " ... ")
   end
   local out = {}
   local _, status = http.request({
      url = url,
      headers = headers,
      method = method,
      sink = ltn12.sink.table(out),
      source = body and ltn12.source.string(body)
   })
   if self.debug then
      util.printout(tostring(status))
   end
   if status ~= 200 then
      return nil, "API returned " .. tostring(status) .. " - " .. redact_api_url(url)
   end
   return json.decode(table.concat(out))
end

end

function api.new(flags)
   local self = {}
   setmetatable(self, { __index = Api })
   self.config = self:load_config() or {}
   self.config.server = flags["server"] or self.config.server or cfg.upload.server
   self.config.version = self.config.version or cfg.upload.version
   self.config.key = flags["temp-key"] or flags["api-key"] or self.config.key
   self.debug = flags["debug"]
   if not self.config.key then
      return nil, "You need an API key to upload rocks.\n" ..
                  "Navigate to "..self.config.server.."/settings to get a key\n" ..
                  "and then pass it through the --api-key=<key> flag."
   end
   if flags["api-key"] then
      self:save_config()
   end
   return self
end

return api