package eino

import (
	"context"
	"encoding/json"
	"errors"
	"strings"
	"testing"
	"time"

	"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
}

// rejectWaiter 是恒拒绝的 HITL 审批替身（fail-safe 路径回归用）。
type rejectWaiter struct{ note string }

func (r *rejectWaiter) WaitApproval(context.Context, string, time.Duration) (*contract.ApprovalDecision, error) {
	return &contract.ApprovalDecision{Approved: false, Note: r.note}, nil
}

// TestComposeApprovalRejectStopsDownstream 钉死 compose 路径的 HITL 审批：
// 审批拒绝须置 errRejected、产出拒绝语，且下游 agent 绝不执行（否则等于审批形同虚设）。
// 这是翻默认前最高危的回归点——execDSLNode 一度没有 approval 分支会把审批节点当未识别跳过。
func TestComposeApprovalRejectStopsDownstream(t *testing.T) {
	graph := `{"version":"1","nodes":[
		{"id":"in","kind":"input","config":{"text":"hi"}},
		{"id":"ap","kind":"approval","config":{"title":"上线审批"}},
		{"id":"a","kind":"agent","config":{"system":"机密操作"}}
	],"edges":[
		{"source":"in","target":"ap"},{"source":"ap","target":"a"}
	]}`
	o := &Orchestrator{pool: echoLLM(), breaker: harness.NewCircuitBreaker(),
		sink: &fakeSink{}, approval: &rejectWaiter{note: "不批"}}
	ans, refs, err := o.runComposeGraph(context.Background(),
		&contract.Task{ID: "t_ap", Graph: []byte(graph)}, &execTracer{})
	if !errors.Is(err, errRejected) {
		t.Fatalf("审批拒绝应返回 errRejected，got %v", err)
	}
	if !strings.Contains(ans, "已被拒绝") {
		t.Fatalf("应产出拒绝语，got %q", ans)
	}
	if strings.Contains(ans, "ANS:") {
		t.Fatalf("审批拒绝后下游 agent 不应执行，但成稿含 agent 产出: %q", ans)
	}
	if refs != nil {
		t.Fatalf("拒绝终态 refs 应为 nil，got %v", refs)
	}
}

// TestComposeReturnsRefs 钉死 compose 路径回传检索来源——曾被硬写成 nil，导致忠实度评测静默失效。
// 与 runGraph 同图对照：两路径都应回流含检索片段的 refs（喂 grounded judge）。
func TestComposeReturnsRefs(t *testing.T) {
	g := `{"nodes":[
		{"id":"i","kind":"input","config":{"text":"介绍杭州西湖"}},
		{"id":"r","kind":"retriever","config":{"kb":"travel"}},
		{"id":"a","kind":"agent","config":{"system":"你是导游"}}
	],"edges":[{"source":"i","target":"r"},{"source":"r","target":"a"}]}`
	ll := &fakeLLM{ready: true, stream: func(m []llm.ChatMessage) string { return m[0].Content }}
	o := newOrch(ll, kbTool(nil), &fakeSink{}, &fakeExec{})
	tk := &contract.Task{ID: "t_refs", Graph: json.RawMessage(g), Meta: map[string]any{contract.MetaUserID: "u42"}}

	_, refs, err := o.runComposeGraph(context.Background(), tk, &execTracer{})
	if err != nil {
		t.Fatalf("runComposeGraph: %v", err)
	}
	if len(refs) == 0 || !strings.Contains(strings.Join(refs, ""), ragSnippet) {
		t.Fatalf("compose 路径应回流含检索片段的 refs，got %v", refs)
	}
}

// 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)
	}
}