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)
	}
}

// TestComposeApprovalInterruptCheckpoints 钉死中断式 HITL（接了 checkpoint 后端）：
// 审批节点应 compose.Interrupt —— 返回 errInterrupted、置 waiting、checkpoint 落盘、下游 agent 不执行。
// 这是「释放 goroutine + 抗重启」的中断半边；恢复半边（resume）由增量3 覆盖。
func TestComposeApprovalInterruptCheckpoints(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"}
	]}`
	kv := newMemKV()
	st := &fakeStatus{}
	fs := &fakeSink{}
	o := &Orchestrator{pool: echoLLM(), breaker: harness.NewCircuitBreaker(), sink: fs, status: st}
	o.SetCheckpoints(kv) // 接 checkpoint 后端 → 审批走中断模型

	task := &contract.Task{ID: "t_intr", Graph: []byte(graph)}
	_, _, err := o.runComposeGraph(context.Background(), task, &execTracer{})

	if !errors.Is(err, errInterrupted) {
		t.Fatalf("审批应中断并返回 errInterrupted，got %v", err)
	}
	if st.last() != contract.TaskWaiting {
		t.Fatalf("中断应置 waiting，got %q", st.last())
	}
	if _, ok, _ := kv.Get(context.Background(), task.ID); !ok {
		t.Fatalf("compose 应把图状态落进 checkpoint（key=task_id），但 KV 未命中")
	}
	if strings.Contains(fs.text(), "ANS:") {
		t.Fatalf("审批中断后下游 agent 不应执行，但 sink 含 agent 产出: %q", fs.text())
	}
}

// approvalGraph 是 input→approval→agent 的最小 HITL 图，agent 用 echoLLM 回 "ANS:<query>"，
// 借此判断审批放行后下游是否真的执行。
const approvalGraph = `{"version":"1","nodes":[
	{"id":"in","kind":"input","config":{"text":"写上线报告"}},
	{"id":"ap","kind":"approval","config":{"title":"上线审批"}},
	{"id":"a","kind":"agent","config":{"system":"报告助手"}}
],"edges":[
	{"source":"in","target":"ap"},{"source":"ap","target":"a"}
]}`

// interruptThenSetup 跑一次 fresh，断言中断并落了 resume 记录，返回可继续 resume 的编排器与任务。
func interruptThenSetup(t *testing.T, kv *memKV, st *fakeStatus) (*Orchestrator, *contract.Task) {
	t.Helper()
	o := &Orchestrator{pool: echoLLM(), breaker: harness.NewCircuitBreaker(), sink: &fakeSink{}, status: st}
	o.SetCheckpoints(kv)
	task := &contract.Task{ID: "t_resume", Graph: []byte(approvalGraph)}
	if _, _, err := o.runComposeGraph(context.Background(), task, &execTracer{}); !errors.Is(err, errInterrupted) {
		t.Fatalf("fresh 跑应中断，got %v", err)
	}
	if _, ok, _ := kv.Get(context.Background(), pendingKey(task.ID)); !ok {
		t.Fatalf("中断应落 resume 记录(pending:%s)", task.ID)
	}
	return o, task
}

// TestComposeApprovalResumeApprove 钉死 HITL 恢复半边——批准：从 checkpoint 重入图，黑板无损还原，
// 下游 agent 执行出稿，终态清 resume 记录 + checkpoint。这条用例也透过 eino 真实 checkpoint 路径
// 验证了 board 序列化（增量2a）端到端可用。
func TestComposeApprovalResumeApprove(t *testing.T) {
	kv, st := newMemKV(), &fakeStatus{}
	o, task := interruptThenSetup(t, kv, st)

	dec := &contract.ApprovalDecision{TaskID: task.ID, Approved: true, Note: "放行"}
	ans, _, err := o.ResumeApproval(context.Background(), task, dec, &execTracer{})
	if err != nil {
		t.Fatalf("批准 resume 不应报错: %v", err)
	}
	if !strings.Contains(ans, "ANS:") {
		t.Fatalf("批准后下游 agent 应执行并出稿，got %q", ans)
	}
	if st.last() != contract.TaskRunning {
		t.Fatalf("批准应把状态从 waiting 拨回 running，got %q", st.last())
	}
	if _, ok, _ := kv.Get(context.Background(), pendingKey(task.ID)); ok {
		t.Fatalf("成功收尾应清 resume 记录")
	}
	if _, ok, _ := kv.Get(context.Background(), task.ID); ok {
		t.Fatalf("成功收尾应清 compose checkpoint")
	}
}

// TestComposeApprovalResumeReject 钉死 HITL 恢复半边——拒绝：resume 置 rejected、返回 errRejected、
// 出拒绝语、下游 agent 不执行、清 checkpoint。
func TestComposeApprovalResumeReject(t *testing.T) {
	kv, st := newMemKV(), &fakeStatus{}
	o, task := interruptThenSetup(t, kv, st)

	dec := &contract.ApprovalDecision{TaskID: task.ID, Approved: false, Note: "不批"}
	ans, refs, err := o.ResumeApproval(context.Background(), task, dec, &execTracer{})
	if !errors.Is(err, errRejected) {
		t.Fatalf("拒绝 resume 应返回 errRejected，got %v", err)
	}
	if !strings.Contains(ans, "已被拒绝") {
		t.Fatalf("应出拒绝语，got %q", ans)
	}
	if strings.Contains(ans, "ANS:") {
		t.Fatalf("拒绝后下游 agent 不应执行，got %q", ans)
	}
	if refs != nil {
		t.Fatalf("拒绝终态 refs 应为 nil，got %v", refs)
	}
	if _, ok, _ := kv.Get(context.Background(), task.ID); ok {
		t.Fatalf("拒绝收尾应清 compose checkpoint")
	}
}

// TestHandleApprovalDecisionResumes 钉死 3b 决定驱动恢复：审批决定到达 → 据 resume 记录续跑 →
// 收尾流 + 判 done + 清记录。这是「持久消费者收决定 → ResumeApproval → finishResumed」的闭环。
func TestHandleApprovalDecisionResumes(t *testing.T) {
	kv, st, fs := newMemKV(), &fakeStatus{}, &fakeSink{}
	o := &Orchestrator{pool: echoLLM(), breaker: harness.NewCircuitBreaker(), sink: fs, status: st}
	o.SetCheckpoints(kv)
	task := &contract.Task{ID: "t_dec", Graph: []byte(approvalGraph)}
	if _, _, err := o.runComposeGraph(context.Background(), task, &execTracer{}); !errors.Is(err, errInterrupted) {
		t.Fatalf("fresh 跑应中断，got %v", err)
	}

	// 决定到达（批准）→ 消费者回调驱动续跑 + 收尾。
	o.HandleApprovalDecision(context.Background(), &contract.ApprovalDecision{TaskID: task.ID, Approved: true})

	if !fs.done {
		t.Fatalf("续跑成功应收尾 Token 流")
	}
	if !strings.Contains(fs.text(), "ANS:") {
		t.Fatalf("批准后应续跑下游 agent，sink=%q", fs.text())
	}
	if st.last() != contract.TaskDone {
		t.Fatalf("续跑成功应判 done，got %q", st.last())
	}
	if _, ok, _ := kv.Get(context.Background(), pendingKey(task.ID)); ok {
		t.Fatalf("成功收尾应清 resume 记录")
	}
}

// TestHandleApprovalDecisionNoPendingIgnored 钉死幂等/兼容：无 resume 记录（阻塞态任务的决定 /
// 决定重投）→ 直接忽略，不收尾、不改状态。
func TestHandleApprovalDecisionNoPendingIgnored(t *testing.T) {
	kv, st, fs := newMemKV(), &fakeStatus{}, &fakeSink{}
	o := &Orchestrator{pool: echoLLM(), breaker: harness.NewCircuitBreaker(), sink: fs, status: st}
	o.SetCheckpoints(kv)

	o.HandleApprovalDecision(context.Background(), &contract.ApprovalDecision{TaskID: "never_interrupted", Approved: true})

	if fs.done || fs.text() != "" {
		t.Fatalf("无 resume 记录不应收尾或产出，sink done=%v text=%q", fs.done, fs.text())
	}
	if seq, _ := st.snapshot(); len(seq) != 0 {
		t.Fatalf("无 resume 记录不应改状态，got %v", seq)
	}
}

// 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)
	}
}