feat(copilot): improved support for AccessToken and Enterprise API

[nathabonfim59]

Implements GitHub Copilot authentication with a new HTTP HttpClient, including token handling and support for new models.

Authentication and Configuration Updates:

• copilot.go: Introduced a new CopilotHTTPClient struct to manage HTTP requests and token handling for Copilot, including methods for retrieving and refreshing tokens. This change also includes defining constants for the Copilot authentication URL, editor version, and user-agent.

• mods.go: Updated the startCompletionCmd function to use the new CopilotHTTPClient for authentication, replacing the previous method of sending the RefreshToken to the API. This ensures that the token is properly managed and refreshed as needed.

Model Configuration Updates:

• config_template.yml: Added new model configurations for gpt-4, gpt-3.5-turbo, o1-preview-2024-09-12, o1-mini-2024-09-12, and claude-3.5-sonnet, including their respective aliases and maximum input characters. Updated the existing gpt-4o model configuration to gpt-4o-2024-05-13 with new aliases.

• copilot.go:

• Add support for Windows file paths using runtime OS detection [1]
• Handle new Copilot token format from apps.json [2]
• Support both legacy and new token storage formats

Future work:

• Cache AccessToken across conversations (refactor(cache): improve caching system and add expiring cache #408)
• Implement Device Authentication flow

Officially, the only way to that is to use the compiled LSP from the VIM plugin[3, 4, 5], so you can generate the ~/.config/github-copilot folder automatically.

But you can also login direcly like a copilot extension[6] and the vscode CopilotChat ApplicationID.

References:

1. https://github.com/orgs/community/discussions/38217#discussioncomment-4059872
2. Copilot chat logged out while autocomplete is logged in zed-industries/zed#21255 (comment)
3. https://github.com/github/copilot.vim
4. https://github.com/MinusGix/lapce-copilot/blob/6b244612043157beb0f509b7ba16de0b5e7d95f4/src/main.rs#L218
5. https://github.com/zed-industries/zed/blob/7e6233d70f329e400e3945ee4307300f3a9df272/crates/copilot/src/copilot.rs#L991
6. https://docs.github.com/en/apps/oauth-apps/building-oauth-apps/authorizing-oauth-apps#device-flow

[caarlos0]

amazing!

[caarlos0]

just a couple of suggestions, but this looks great, and works well too!

thanks so much!

[nathabonfim59]

I really appreciate it!

Suggestions implemented and fixed the linting errors.

Thinking back about what you said, it doesn't really make sense to export those copilot specific constants either.

I left just the CopilotAccessToken as it could be used by a third party to check if the token is expired or other metadata.

[nathabonfim59]

BTW, yesterday, GitHub announced a new "Free Tier" with limited access (50 chat requests/month).

My guess is that they are using CopilotAccessToken.ErrorDetails.Message to tell if someone has used up all chat messages for the month. In this case, no changes would be necessary.

I don't have a GitHub account without a Copilot subscription, but if someone could verify this, please let me know.

[caarlos0]

Thanks for the PR ❤️