fix: use OpenAI provider for Doubao multimodal models

DeepSeek provider was not properly formatting image content for Doubao's
API. Now uses OpenAI provider for Doubao models (multimodal support),
while keeping DeepSeek provider for DeepSeek/Kimi models on the platform.

Dockerfile

@@ -30,6 +30,10 @@ ENV NEXT_PUBLIC_DRAWIO_BASE_URL=${NEXT_PUBLIC_DRAWIO_BASE_URL}
 ARG NEXT_PUBLIC_SHOW_ABOUT_AND_NOTICE=false
 ENV NEXT_PUBLIC_SHOW_ABOUT_AND_NOTICE=${NEXT_PUBLIC_SHOW_ABOUT_AND_NOTICE}
 
+# Build-time argument for subdirectory deployment (e.g., /nextaidrawio)
+ARG NEXT_PUBLIC_BASE_PATH=""
+ENV NEXT_PUBLIC_BASE_PATH=${NEXT_PUBLIC_BASE_PATH}
+
 # Build Next.js application (standalone mode)
 RUN npm run build
 

app/api/validate-model/route.ts

@@ -251,13 +251,26 @@ export async function POST(req: Request) {
             }
 
             case "doubao": {
-                // ByteDance Doubao uses DeepSeek-compatible API
-                const doubao = createDeepSeek({
-                    apiKey,
-                    baseURL:
-                        baseUrl || "https://ark.cn-beijing.volces.com/api/v3",
-                })
-                model = doubao(modelId)
+                // ByteDance Doubao: use DeepSeek for DeepSeek/Kimi models, OpenAI for others
+                const doubaoBaseUrl =
+                    baseUrl || "https://ark.cn-beijing.volces.com/api/v3"
+                const lowerModelId = modelId.toLowerCase()
+                if (
+                    lowerModelId.includes("deepseek") ||
+                    lowerModelId.includes("kimi")
+                ) {
+                    const doubao = createDeepSeek({
+                        apiKey,
+                        baseURL: doubaoBaseUrl,
+                    })
+                    model = doubao(modelId)
+                } else {
+                    const doubao = createOpenAI({
+                        apiKey,
+                        baseURL: doubaoBaseUrl,
+                    })
+                    model = doubao.chat(modelId)
+                }
                 break
             }
 

lib/ai-providers.ts

@@ -871,11 +871,24 @@ export function getAIModel(overrides?: ClientOverrides): ModelConfig {
                 overrides?.baseUrl ||
                 process.env.DOUBAO_BASE_URL ||
                 "https://ark.cn-beijing.volces.com/api/v3"
-            const doubaoProvider = createDeepSeek({
-                apiKey,
-                baseURL,
-            })
-            model = doubaoProvider(modelId)
+            const lowerModelId = modelId.toLowerCase()
+            // Use DeepSeek provider for DeepSeek/Kimi models, OpenAI for others (multimodal support)
+            if (
+                lowerModelId.includes("deepseek") ||
+                lowerModelId.includes("kimi")
+            ) {
+                const doubaoProvider = createDeepSeek({
+                    apiKey,
+                    baseURL,
+                })
+                model = doubaoProvider(modelId)
+            } else {
+                const doubaoProvider = createOpenAI({
+                    apiKey,
+                    baseURL,
+                })
+                model = doubaoProvider.chat(modelId)
+            }
             break
         }