✨ feat: Add /recent command for viewing user submissions

[cxyfer]

Summary

• Added new /recent slash command to view any LeetCode user's recent accepted submissions
• Implemented paginated display showing one problem per page with navigation controls
• Added lazy loading to improve performance by fetching problem details only when needed

Features

• Paginated Interface: Display submissions one at a time with previous/next navigation buttons
• Lazy Loading: Fetch problem details only when viewing specific pages, reducing initial load time
• Submission Caching: 5-minute cache to avoid re-fetching when navigating between pages
• Clean UI: Navigation buttons at edges without text labels, English timestamps and page indicators
• Flexible Limit: Support up to 50 recent submissions with customizable limit parameter

Changes

• Modified leetcode.py:
  • Made fetch_recent_ac_submissions async with aiohttp
  • Return basic submission info without fetching full problem details
• Updated cogs/slash_commands_cog.py:
  • Added /recent command with username and limit parameters
  • Implemented helper methods for creating embeds and views
  • Added _get_submission_details for lazy loading problem information
• Enhanced cogs/interaction_handler_cog.py:
  • Added navigation button handlers for previous/next actions
  • Implemented submission caching with TTL
  • Support lazy loading when switching pages

Test Plan

• Test /recent command with valid username
• Test navigation between multiple submissions
• Verify lazy loading works correctly
• Check cache expiration after 5 minutes
• Test with different submission limits
• Verify error handling for invalid usernames

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR adds a new /recent slash command to fetch and display a LeetCode user's recent accepted submissions with pagination, lazy loading of problem details, and a short-term cache.

• Converted fetch_recent_ac_submissions to async and return only basic info for lazy loading.
• Introduced /recent command in SlashCommandsCog with paginated embeds and caching.
• Added navigation handlers and a TTL-based submissions cache in InteractionHandlerCog.

Reviewed Changes

Copilot reviewed 3 out of 13 changed files in this pull request and generated 2 comments.

File	Description
leetcode.py	Made fetch_recent_ac_submissions async, added domain check, and built basic submission info
cogs/slash_commands_cog.py	Added /recent command, helper methods for embeds/views, and caching logic
cogs/interaction_handler_cog.py	Implemented prev/next button handlers, cache lookup/refresh, and page navigation

Comments suppressed due to low confidence (4)

leetcode.py:621

• The method now returns early for non-.com domains but this limitation is not documented in the docstring; consider updating the docstring to mention domain restriction.

        if self.domain != "com":

cogs/slash_commands_cog.py:345

• New pagination and caching behaviors were added but there are no corresponding tests; consider adding unit tests for the /recent command, page navigation, and cache expiration logic.

    @app_commands.command(name="recent", description="查看 LeetCode 使用者的近期解題紀錄 (僅限 LCUS)")

cogs/slash_commands_cog.py:392

• self.logger is used here but there's no evidence that self.logger is initialized in this cog; you may need to define it in __init__ or use self.bot.logger to avoid an AttributeError.

            self.logger.info(f"Sent user submissions for {username} to {interaction.user.name}")

cogs/slash_commands_cog.py:472

• [nitpick] The constant LEETCODE_DISCRIPTION_BUTTON_PREFIX appears to have a typo ('DISCRIPTION' vs 'DESCRIPTION'); consider renaming for clarity.

            custom_id=f"{self.bot.LEETCODE_DISCRIPTION_BUTTON_PREFIX}{submission['id']}_com",

[Copilot]

[nitpick] Accessing cached_data by index makes the code harder to read; consider unpacking the tuple as (submissions, timestamp, original_limit) = cached_data for clarity.

Suggested change

	cached_data = self.submissions_cache.get(cache_key)
	# Check if cache is valid (5 minutes)
	if cached_data and (time.time() - cached_data[1]) < 300:
	submissions = cached_data[0]
	else:
	# Fetch submissions again
	await interaction.response.defer(ephemeral=True)
	# Use the original limit if available, otherwise default to 50
	original_limit = cached_data[2] if cached_data and len(cached_data) > 2 else 50
	submissions = await self.bot.lcus.fetch_recent_ac_submissions(username, original_limit)
	if not submissions:
	await interaction.followup.send(f"找不到使用者 **{username}** 的解題紀錄。", ephemeral=True)
	return
	# Update cache with limit
	self.submissions_cache[cache_key] = (submissions, time.time(), original_limit)
	cached_data = self.submissions_cache.get(cache_key)
	# Unpack cached data
	if cached_data:
	submissions, timestamp, original_limit = cached_data
	else:
	submissions, timestamp, original_limit = None, None, 50
	# Check if cache is valid (5 minutes)
	if submissions and (time.time() - timestamp) < 300:
	pass # Use cached submissions
	else:
	# Fetch submissions again
	await interaction.response.defer(ephemeral=True)
	submissions = await self.bot.lcus.fetch_recent_ac_submissions(username, original_limit)
	if not submissions:
	await interaction.followup.send(f"找不到使用者 **{username}** 的解題紀錄。", ephemeral=True)
	return
	# Update cache with limit
	self.submissions_cache[cache_key] = (submissions, time.time(), original_limit)

[Copilot]

[nitpick] The author name is in English while command messages are in Chinese; consider localizing all UI strings consistently based on user language.

Suggested change

	embed.set_author(name=f"{username}'s Recent Submissions", icon_url="https://leetcode.com/static/images/LeetCode_logo.png")
	localized_author_name = self._translate("Recent Submissions", username)
	embed.set_author(name=localized_author_name, icon_url="https://leetcode.com/static/images/LeetCode_logo.png")