refactor: improve thinking logic

internal/thinking/strip.go

@@ -0,0 +1,54 @@
+// Package thinking provides unified thinking configuration processing.
+package thinking
+
+import (
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+// StripThinkingConfig removes thinking configuration fields from request body.
+//
+// This function is used when a model doesn't support thinking but the request
+// contains thinking configuration. The configuration is silently removed to
+// prevent upstream API errors.
+//
+// Parameters:
+//   - body: Original request body JSON
+//   - provider: Provider name (determines which fields to strip)
+//
+// Returns:
+//   - Modified request body JSON with thinking configuration removed
+//   - Original body is returned unchanged if:
+//   - body is empty or invalid JSON
+//   - provider is unknown
+//   - no thinking configuration found
+func StripThinkingConfig(body []byte, provider string) []byte {
+	if len(body) == 0 || !gjson.ValidBytes(body) {
+		return body
+	}
+
+	switch provider {
+	case "claude":
+		result, _ := sjson.DeleteBytes(body, "thinking")
+		return result
+	case "gemini":
+		result, _ := sjson.DeleteBytes(body, "generationConfig.thinkingConfig")
+		return result
+	case "gemini-cli", "antigravity":
+		result, _ := sjson.DeleteBytes(body, "request.generationConfig.thinkingConfig")
+		return result
+	case "openai":
+		result, _ := sjson.DeleteBytes(body, "reasoning_effort")
+		return result
+	case "codex":
+		result, _ := sjson.DeleteBytes(body, "reasoning.effort")
+		return result
+	case "iflow":
+		result, _ := sjson.DeleteBytes(body, "chat_template_kwargs.enable_thinking")
+		result, _ = sjson.DeleteBytes(result, "chat_template_kwargs.clear_thinking")
+		result, _ = sjson.DeleteBytes(result, "reasoning_split")
+		return result
+	default:
+		return body
+	}
+}