package eino

import (
	"context"
	"fmt"
	"io"
	"os"
	"time"

	"github.com/cloudwego/eino/compose"
	"github.com/cloudwego/eino/schema"

	"github.com/sundynix/sundynix-dispatcher/internal/harness"
)

// composeEnabled 报告是否启用 compose.Graph 编排路径（Phase C 灰度开关，默认关 → 走自研 graph.go）。
// 并存策略：EINO_COMPOSE=1 时对话主流程改走 Eino compose 运行时，行为对齐后再逐步退役 graph.go。
func composeEnabled() bool { return os.Getenv("EINO_COMPOSE") == "1" }

// runConversation 是对话/模型节点的统一入口：按灰度开关选 compose.Graph 或自研 runAgent。
// 二者对外行为一致（据黑板拼消息 → 流式回流 token → 累计成稿），便于等价回归。
func (o *Orchestrator) runConversation(ctx context.Context, taskID string, b *board, system string, tr *execTracer, node string) {
	if composeEnabled() {
		o.runComposeConversation(ctx, taskID, b, system, tr, node)
		return
	}
	o.runAgent(ctx, taskID, b, system, tr, node)
}

// runComposeConversation 用 Eino compose.Graph 跑对话主流程：
// START → ChatModel 节点 → END，编译为 Runnable 后流式执行；可观测经 callbacks 桥到 ExecEvent。
// 模型未就绪 / 编译失败时降级回自研 runAgent，保证不回归。
func (o *Orchestrator) runComposeConversation(ctx context.Context, taskID string, b *board, system string, tr *execTracer, node string) {
	cm := o.pool.ChatModel()
	if cm == nil {
		o.runAgent(ctx, taskID, b, system, tr, node) // 无模型 → 走自研路径的降级桩
		return
	}

	g := compose.NewGraph[[]*schema.Message, *schema.Message]()
	if err := g.AddChatModelNode("model", cm); err != nil {
		tr.info(node, "system", "compose 降级", "建图失败，退回自研路径："+err.Error())
		o.runAgent(ctx, taskID, b, system, tr, node)
		return
	}
	_ = g.AddEdge(compose.START, "model")
	_ = g.AddEdge("model", compose.END)
	r, err := g.Compile(ctx)
	if err != nil {
		tr.info(node, "system", "compose 降级", "编译失败，退回自研路径："+err.Error())
		o.runAgent(ctx, taskID, b, system, tr, node)
		return
	}

	rc := &RunCtx{
		UserID: b.uid, SessionID: b.sid,
		System:  firstNonEmpty(system, defaultAgentSystem),
		Query:   b.query,
		Profile: b.profile,
		History: b.history,
		ToolOut: append(append([]string{}, b.toolOut...), b.refs...),
	}
	msgs, _ := buildMessages(ctx, rc)

	t0 := time.Now()
	// ChatModel 的 start/end 由 composeTracer（callbacks）落轨迹，这里不再手写 emit（归一）。
	sr, err := r.Stream(ctx, msgs, compose.WithCallbacks(composeTracer(tr, node)))
	if err != nil {
		tr.emit(node, "model", "error", "compose 图执行", err.Error(), time.Since(t0).Milliseconds())
		return
	}
	defer sr.Close()

	chunks := 0
	for {
		chunk, rerr := sr.Recv()
		if rerr == io.EOF {
			break
		}
		if rerr != nil {
			tr.emit(node, "model", "error", "compose 图执行", rerr.Error(), time.Since(t0).Milliseconds())
			return
		}
		if chunk.Content == "" {
			continue
		}
		safe, _ := harness.RedactSecrets(chunk.Content) // 输出护栏：逐片脱敏
		_ = o.sink.PublishToken(taskID, []byte(safe))
		b.answer += safe
		chunks++
	}
	tr.info(node, "system", "compose 图", fmt.Sprintf("%d 段输出 / %d 字（Eino compose 运行时）", chunks, len([]rune(b.answer))))
}