package eino

import (
	"context"
	"testing"

	"github.com/sundynix/sundynix-dispatcher/internal/harness"
	"github.com/sundynix/sundynix-dispatcher/internal/llm"
	"github.com/sundynix/sundynix-shared/contract"
)

// echoLLM 回显最后一条 user 消息内容（确定性），便于两条执行路径逐字对比。
func echoLLM() *fakeLLM {
	return &fakeLLM{
		ready: true,
		stream: func(m []llm.ChatMessage) string {
			for i := len(m) - 1; i >= 0; i-- {
				if m[i].Role == "user" {
					return "ANS:" + m[i].Content
				}
			}
			return "ANS:"
		},
	}
}

func runBoth(t *testing.T, graph string) (interp, comp string) {
	t.Helper()
	task := &contract.Task{ID: "t_eq", Graph: []byte(graph)}

	o1 := &Orchestrator{pool: echoLLM(), breaker: harness.NewCircuitBreaker(), sink: &fakeSink{}}
	a1, _, err := o1.runGraph(context.Background(), task, &execTracer{})
	if err != nil {
		t.Fatalf("runGraph: %v", err)
	}
	o2 := &Orchestrator{pool: echoLLM(), breaker: harness.NewCircuitBreaker(), sink: &fakeSink{}}
	a2, err := o2.runComposeGraph(context.Background(), task, &execTracer{})
	if err != nil {
		t.Fatalf("runComposeGraph: %v", err)
	}
	return a1, a2
}

// TestComposeEquivalentLinear 多节点线性图：input→memory→agent→output，两路径成稿应逐字一致。
func TestComposeEquivalentLinear(t *testing.T) {
	graph := `{"version":"1","nodes":[
		{"id":"in","kind":"input","config":{"text":"什么是图编排"}},
		{"id":"m","kind":"memory","config":{}},
		{"id":"a","kind":"agent","config":{"system":"你是助手"}},
		{"id":"out","kind":"output","config":{}}
	],"edges":[
		{"source":"in","target":"m"},{"source":"m","target":"a"},{"source":"a","target":"out"}
	]}`
	interp, comp := runBoth(t, graph)
	if interp == "" || interp != comp {
		t.Fatalf("线性图不等价: interp=%q compose=%q", interp, comp)
	}
}

// TestComposeEquivalentBranch 分支图：input→branch→(真)A/(假)B，条件恒真应都走 A，两路径一致。
func TestComposeEquivalentBranch(t *testing.T) {
	graph := `{"version":"1","nodes":[
		{"id":"in","kind":"input","config":{"text":"hi"}},
		{"id":"br","kind":"branch","config":{"condition":""}},
		{"id":"a","kind":"agent","config":{"system":"A"}},
		{"id":"b","kind":"agent","config":{"system":"B"}}
	],"edges":[
		{"source":"in","target":"br"},
		{"source":"br","target":"a","sourceHandle":"true"},
		{"source":"br","target":"b","sourceHandle":"false"}
	]}`
	interp, comp := runBoth(t, graph)
	if interp == "" || interp != comp {
		t.Fatalf("分支图不等价: interp=%q compose=%q", interp, comp)
	}
}