import { Router } from "express";
import { z } from "zod";
import { logger } from "../logger.js";
const payloadSchema = z.object({
    message: z.string().min(1).max(10000),
    conversation_id: z.string().max(128).optional(),
});
export const buildChatRouter = (sessionBridge, runtime) => {
    const chatRouter = Router();
    chatRouter.post("/stream", async (req, res) => {
        const parsed = payloadSchema.safeParse(req.body);
        if (!parsed.success) {
            res.status(400).json({
                message: "invalid request payload",
                detail: parsed.error.flatten(),
            });
            return;
        }
        try {
            const authHeader = req.header("authorization");
            const accessToken = authHeader?.startsWith("Bearer ")
                ? authHeader.slice("Bearer ".length)
                : authHeader;
            const projectId = req.header("x-project-id") ?? undefined;
            const traceId = req.header("x-trace-id") ?? undefined;
            const { binding, requestContext, created } = await sessionBridge.resolve({
                conversationId: parsed.data.conversation_id,
                accessToken,
                projectId,
                traceId,
            });
            logger.info({
                conversationId: requestContext.conversationId,
                sessionId: binding.sessionId,
                created,
                traceId: requestContext.traceId,
                projectId: requestContext.projectId,
            }, "processing chat request");
            // 当前先走“发送 prompt 后回读最近消息”的兼容实现。
            // 后续切到真正的 opencode 事件流时，只需要替换这里的取数方式。
            const messages = await runtime.sendPrompt(binding.sessionId, parsed.data.message);
            const assistantMessage = messages.find((message) => message.info.role === "assistant");
            res.status(200);
            res.setHeader("Content-Type", "text/event-stream; charset=utf-8");
            res.setHeader("Cache-Control", "no-cache");
            res.setHeader("Connection", "keep-alive");
            res.setHeader("X-Accel-Buffering", "no");
            const conversationId = requestContext.conversationId;
            const parts = assistantMessage?.parts ?? [];
            const textContent = collectTextContent(parts);
            if (textContent) {
                res.write(toSse("token", {
                    conversationId,
                    content: textContent,
                }));
            }
            for (const toolCall of collectToolCalls(parts)) {
                res.write(toSse("tool_call", {
                    conversationId,
                    tool: toolCall.tool,
                    params: toolCall.params,
                }));
            }
            if (assistantMessage?.info.role === "assistant" && assistantMessage.info.error) {
                res.write(toSse("error", {
                    conversationId,
                    message: getErrorMessage(assistantMessage.info.error),
                    detail: assistantMessage.info.error.name,
                }));
            }
            else if (!assistantMessage) {
                res.write(toSse("error", {
                    conversationId,
                    message: "assistant response unavailable",
                    detail: "no assistant message found after prompt",
                }));
            }
            else {
                res.write(toSse("done", { conversationId }));
            }
            res.end();
        }
        catch (error) {
            const detail = error instanceof Error ? error.message : String(error);
            logger.error({ err: error }, "chat stream failed");
            res.status(500).json({
                message: "chat stream failed",
                detail,
            });
        }
    });
    return chatRouter;
};
const toSse = (event, data) => `event: ${event}\ndata: ${JSON.stringify(data)}\n\n`;
// 先把 opencode 的 Part 结构压平成前端当前消费的 SSE 语义。
const collectTextContent = (parts) => parts
    .filter((part) => part.type === "text")
    .map((part) => part.text)
    .join("");
const collectToolCalls = (parts) => parts
    .filter((part) => part.type === "tool")
    .map((part) => ({
    tool: part.tool,
    params: part.state.input,
}));
const getErrorMessage = (error) => error.data?.message ?? error.name;