feat: caching

lua/cp/cache.lua

@@ -0,0 +1,90 @@
+local M = {}
+
+local cache_file = vim.fn.stdpath("data") .. "/cp-contest-cache.json"
+local cache_data = {}
+
+local function get_expiry_date(contest_type)
+	if contest_type == "cses" then
+		return os.time() + (30 * 24 * 60 * 60)
+	end
+	return nil
+end
+
+local function is_cache_valid(contest_data, contest_type)
+	if contest_type ~= "cses" then
+		return true
+	end
+
+	local expires_at = contest_data.expires_at
+	if not expires_at then
+		return false
+	end
+
+	return os.time() < expires_at
+end
+
+function M.load()
+	if vim.fn.filereadable(cache_file) == 0 then
+		cache_data = {}
+		return
+	end
+
+	local content = vim.fn.readfile(cache_file)
+	if #content == 0 then
+		cache_data = {}
+		return
+	end
+
+	local ok, decoded = pcall(vim.json.decode, table.concat(content, "\n"))
+	if ok then
+		cache_data = decoded
+	else
+		cache_data = {}
+	end
+end
+
+function M.save()
+	vim.fn.mkdir(vim.fn.fnamemodify(cache_file, ":h"), "p")
+	local encoded = vim.json.encode(cache_data)
+	vim.fn.writefile(vim.split(encoded, "\n"), cache_file)
+end
+
+function M.get_contest_data(contest_type, contest_id)
+	if not cache_data[contest_type] then
+		return nil
+	end
+
+	local contest_data = cache_data[contest_type][contest_id]
+	if not contest_data then
+		return nil
+	end
+
+	if not is_cache_valid(contest_data, contest_type) then
+		return nil
+	end
+
+	return contest_data
+end
+
+function M.set_contest_data(contest_type, contest_id, problems)
+	if not cache_data[contest_type] then
+		cache_data[contest_type] = {}
+	end
+
+	cache_data[contest_type][contest_id] = {
+		problems = problems,
+		scraped_at = os.date("%Y-%m-%d"),
+		expires_at = get_expiry_date(contest_type),
+	}
+
+	M.save()
+end
+
+function M.clear_contest_data(contest_type, contest_id)
+	if cache_data[contest_type] and cache_data[contest_type][contest_id] then
+		cache_data[contest_type][contest_id] = nil
+		M.save()
+	end
+end
+
+return M