News: Search news by id

And not by index. There would be bazzilion mistakes that way.

hrochobot/cogs/news.py

@@ -50,14 +50,19 @@ def format_entry(entry, author=None):
 
     return embed
 
-async def post_news(bot, guild, index):
+async def post_news(bot, guild, entry_id):
     news_json = data.load_guild_data(guild.id, NEWS_JSON)
     if "news_channel" not in news_json:
-        return
+        return "News channel not set."
 
     channel = get(guild.channels, id=news_json["news_channel"])
     feed = await ksp_feed()
-    return await channel.send(embed=format_entry(feed.entries[index], author=feed.feed.author))
+    entries_with_id = list(filter(lambda e: e.id == f"https://ksp.mff.cuni.cz/news_{entry_id}", feed.entries))
+    if len(entries_with_id) == 0:
+        return f"Entry with id ``{entry_id}`` not found."
+
+    await channel.send(embed=format_entry(entries_with_id[0], author=feed.feed.author))
+    return None
 
 
 class News(commands.Cog):
@@ -79,9 +84,11 @@ class News(commands.Cog):
         return await ctx.respond(f"News channel set to {channel.mention}.", ephemeral=True)
 
     @news.command(description="Synchronize news feed.")
-    @discord.option("index", int, description="Send index-th most recent entry. (indexed from 0)")
-    async def post_news(self, ctx, index: int):
-        await post_news(self.bot, ctx.guild, index)
+    @discord.option("id", str, description="Id of entry to send.")
+    async def post_news(self, ctx, id: int):
+        err = await post_news(self.bot, ctx.guild, id)
+        if err:
+            return await ctx.respond(err, ephemeral=True)
         return await ctx.respond(f"News posted.", ephemeral=True)