feature: Support new OpenAI o1 reasoning models

[abatilo]

Feature request

I would like if Avante could prompt against the OAI reasoning models

Motivation

These reasoning models are allegedly more capable at coding.

Other

There are a few differences in the API now:

1. temperature must be set to 1 if you're using either o1-preview or o1-mini models.
2. max_tokens is not used. Instead max_completion_tokens must be used in the config
3. These models do not support a system role/message. I think we need to remove this line
4. Streaming is not supported, so I believe we need to remove this line.

Even with these changes, I'm not getting a successful end to end flow. I've never contributed to the avante.nvim codebase and I'm not entirely sure what else to try at the moment to get things working.

So far, my total diffs look like so:

diff --git a/lua/avante/config.lua b/lua/avante/config.lua
index c1689d7..82d3477 100644
--- a/lua/avante/config.lua
+++ b/lua/avante/config.lua
@@ -30,8 +30,8 @@ You are an excellent programming expert.
     endpoint = "https://api.openai.com/v1",
     model = "gpt-4o",
     timeout = 30000, -- Timeout in milliseconds
-    temperature = 0,
-    max_tokens = 4096,
+    temperature = 1,
+    max_completion_tokens = 4096,
     ["local"] = false,
   },
   ---@type AvanteSupportedProvider
diff --git a/lua/avante/providers/openai.lua b/lua/avante/providers/openai.lua
index 52e62b1..888d466 100644
--- a/lua/avante/providers/openai.lua
+++ b/lua/avante/providers/openai.lua
@@ -51,7 +51,6 @@ M.parse_message = function(opts)
   end

   return {
-    { role = "system", content = opts.system_prompt },
     { role = "user", content = user_content },
   }
 end
@@ -91,7 +90,6 @@ M.parse_curl_args = function(provider, code_opts)
     body = vim.tbl_deep_extend("force", {
       model = base.model,
       messages = M.parse_message(code_opts),
-      stream = true,
     }, body_opts),
   }
 end

I've gotten this far by trying to use the openai provider and seeing it fail and return an error message. This time, it's not returning anything. I see Generating response ... and it never changes.

[Alextibtab]

I assume they'll open it up in the near future but currently to use the reasoning models via the API you need to hit tier 5 https://platform.openai.com/docs/guides/rate-limits/usage-tiers?context=tier-five meaning you have to have bought $1000 in tokens

[cfcosta]

@Alextibtab if you need to test anything I have this level of API access.

[aarnphm]

lmao if you have tier 5 then feel free to use it. For now we have to wait till GA for API usage.

btw the API costs would be pretty high for o1 from my testing.