1 files changed, 109 insertions, 0 deletions
diff --git a/bot/exts/evergreen/source.py b/bot/exts/evergreen/source.py
new file mode 100644
index 00000000..cdfe54ec
--- /dev/null
+++ b/bot/exts/evergreen/source.py
@@ -0,0 +1,109 @@
+import inspect
+from pathlib import Path
+from typing import Optional, Tuple, Union
+
+from discord import Embed
+from discord.ext import commands
+
+from bot.constants import Source
+
+SourceType = Union[commands.Command, commands.Cog, str, commands.ExtensionNotLoaded]
+
+
+class SourceConverter(commands.Converter):
+    """Convert an argument into a help command, tag, command, or cog."""
+
+    async def convert(self, ctx: commands.Context, argument: str) -> SourceType:
+        """Convert argument into source object."""
+        cog = ctx.bot.get_cog(argument)
+        if cog:
+            return cog
+
+        cmd = ctx.bot.get_command(argument)
+        if cmd:
+            return cmd
+
+        raise commands.BadArgument(
+            f"Unable to convert `{argument}` to valid command or Cog."
+        )
+
+
+class BotSource(commands.Cog):
+    """Displays information about the bot's source code."""
+
+    def __init__(self, bot: commands.Bot):
+        self.bot = bot
+
+    @commands.command(name="source", aliases=("src",))
+    async def source_command(self, ctx: commands.Context, *, source_item: SourceConverter = None) -> None:
+        """Display information and a GitHub link to the source code of a command, tag, or cog."""
+        if not source_item:
+            embed = Embed(title="Sir Lancebot's GitHub Repository")
+            embed.add_field(name="Repository", value=f"[Go to GitHub]({Source.github})")
+            embed.set_thumbnail(url=Source.github_avatar_url)
+            await ctx.send(embed=embed)
+            return
+
+        embed = await self.build_embed(source_item)
+        await ctx.send(embed=embed)
+
+    def get_source_link(self, source_item: SourceType) -> Tuple[str, str, Optional[int]]:
+        """
+        Build GitHub link of source item, return this link, file location and first line number.
+
+        Raise BadArgument if `source_item` is a dynamically-created object (e.g. via internal eval).
+        """
+        if isinstance(source_item, commands.Command):
+            src = source_item.callback.__code__
+            filename = src.co_filename
+        else:
+            src = type(source_item)
+            try:
+                filename = inspect.getsourcefile(src)
+            except TypeError:
+                raise commands.BadArgument("Cannot get source for a dynamically-created object.")
+
+        if not isinstance(source_item, str):
+            try:
+                lines, first_line_no = inspect.getsourcelines(src)
+            except OSError:
+                raise commands.BadArgument("Cannot get source for a dynamically-created object.")
+
+            lines_extension = f"#L{first_line_no}-L{first_line_no+len(lines)-1}"
+        else:
+            first_line_no = None
+            lines_extension = ""
+
+        file_location = Path(filename).relative_to(Path.cwd()).as_posix()
+
+        url = f"{Source.github}/blob/master/{file_location}{lines_extension}"
+
+        return url, file_location, first_line_no or None
+
+    async def build_embed(self, source_object: SourceType) -> Optional[Embed]:
+        """Build embed based on source object."""
+        url, location, first_line = self.get_source_link(source_object)
+
+        if isinstance(source_object, commands.Command):
+            if source_object.cog_name == 'Help':
+                title = "Help Command"
+                description = source_object.__doc__.splitlines()[1]
+            else:
+                description = source_object.short_doc
+                title = f"Command: {source_object.qualified_name}"
+        else:
+            title = f"Cog: {source_object.qualified_name}"
+            description = source_object.description.splitlines()[0]
+
+        embed = Embed(title=title, description=description)
+        embed.set_thumbnail(url=Source.github_avatar_url)
+        embed.add_field(name="Source Code", value=f"[Go to GitHub]({url})")
+        line_text = f":{first_line}" if first_line else ""
+        embed.set_footer(text=f"{location}{line_text}")
+
+        return embed
+
+
+def setup(bot: commands.Bot) -> None:
+    """Load the BotSource cog."""
+    bot.add_cog(BotSource(bot))