local mastodon = {}

local json = require("json")

function url_form_encode(data)
	local str = ""
	for k, v in pairs(data) do
		if #str == 0 then
			str = k .. "=" .. v
		else
			str = str .. "&" .. k .. "=" .. v
		end
	end
	return str
end

function mastodon.create_app(api_base_url, client_name)
	if string.sub(api_base_url, -1) == "/" then
		api_base_url = string.sub(api_base_url, 1, -2)
	end

    local request_data = url_form_encode({
		client_name = client_name,
		redirect_uris = "urn:ietf:wg:oauth:2.0:oob",
		scopes = "read write follow"
	})

	local h = http.post(api_base_url .. "/api/v1/apps", request_data)
	if h.getResponseCode() == 200 then
		data = json.decode(h.readAll())

		return {
			client_id = data["client_id"],
			client_secret = data["client_secret"]
		}
	else
		return nil, "Unexpected response code: " .. h.getResponseCode()
	end
end

local Mastodon = {}

function mastodon.new(options)
	local self = {
		api_base_url = options.api_base_url,
		client_id = options.client_id,
		client_secret = options.client_secret,
		access_token = options.access_token,
		debug_requests = options.debug_requests or false
	}

	if not self.api_base_url then
		-- read credentials from file
		local h = fs.open("creds.txt", "r")
		self.api_base_url = h.readLine()
		self.client_id = h.readLine()
		self.client_secret = h.readLine()
		local last_line = h.readLine()
		if last_line ~= "" then
			self.access_token = last_line
		end
	end

	if string.sub(self.api_base_url, -1) == "/" then
		self.api_base_url = string.sub(self.api_base_url, 1, -2)
	end

	return setmetatable(self, {__index = Mastodon})
end

 function Mastodon:get_auth_url()
	 return self.api_base_url .. "/oauth/authorize?scope=read%20write%20follow&response_type=code&redirect_uri=urn:ietf:wg:oauth:2.0:oob&client_id=" .. self.client_id
 end

 function Mastodon:get_access_token(auth_code)
	 local request_data = url_form_encode({
		 client_id = self.client_id,
		 client_secret = self.client_secret,
		 grant_type = "authorization_code",
		 code = auth_code,
		 redirect_uri = "urn:ietf:wg:oauth:2.0:oob"
	 })
	 local h = http.post(self.api_base_url .. "/oauth/token", request_data)
	 if h.getResponseCode() == 200 then
		 data = json.decode(h.readAll())

		 print(data)
	 else
		 return self, "Unexpected response code: " .. h.getResponseCode()
	 end
 end

function Mastodon:get_own_account()
	local headers = {
		["Authorization"] = "Bearer " .. self.access_token
	}
	local h = http.get(self.api_base_url .. "/api/v1/accounts/verify_credentials", headers)
	if h.getResponseCode() == 200 then
		data = json.decode(h.readAll())

		print(data["acct"])
	else
		return nil, "Unexpected response code: " .. h.getResponseCode()
	end
end

return mastodon