package runtime

import (
	"encoding/json"
	"fmt"
	"strings"
	"time"

	"agent-native/runtime/gates"
	agentllm "agent-native/runtime/llm"
	"agent-system-backend/internal/workflow"
	core "agent-system-core"
)

const workflowPlannerID = "agent.sub.workflow-plan"

// WorkflowRunner 执行启动时拷贝下来的工作流定义。
type WorkflowRunner struct {
	// JudgeStream 注入验收模型。nil 时按轻量模型构造客户端。
	JudgeStream agentllm.StreamFunc
	// ScriptTimeout 覆盖脚本墙钟超时。0 表示 600 秒，超过 1800 秒会被截断。
	ScriptTimeout time.Duration
}

func (WorkflowRunner) Name() string { return "workflow" }

type workflowSource interface {
	Workflow() (workflow.Launch, bool)
}

type workflowOutcome struct {
	Summary   string
	Parts     []core.Part
	Artifacts []*core.ArtifactRef
}

// planWorkflow 让规划子代理写出步骤，校验通过后必须经用户确认才执行。
func planWorkflow(rc RunCtx, goal string, runner WorkflowRunner) (workflowOutcome, error) {
	sp, ok := rc.(interface {
		SpawnAgent(agentID, name, task, hint string) (core.AgentResultPayload, error)
	})
	if !ok {
		return workflowOutcome{}, fmt.Errorf("workflow: 当前运行不能规划")
	}
	res, err := sp.SpawnAgent(workflowPlannerID, "规划", "把下面的目标规划成 WorkflowDef。只输出 JSON，不要完成目标本身。\n目标："+goal, "")
	if err != nil {
		return workflowOutcome{}, err
	}
	text := res.Text
	if text == "" {
		text = res.Summary
	}
	def, err := parseWorkflowDef(text)
	if err != nil {
		return workflowOutcome{}, err
	}
	known := map[string]bool{}
	for _, tool := range rc.Tools() {
		known[tool.Name] = true
	}
	if err := workflow.Validate(def, workflow.DynamicLimits(), func(name string) bool { return known[name] }); err != nil {
		return workflowOutcome{}, err
	}
	resp, err := rc.AskHITL(core.HITLCard{
		Question: planPreview(def), Kind: core.HITLKindConfirm, AllowFreeInput: false,
		Choices: []core.HITLChoice{
			{ID: "yes", Label: "执行", Description: "按这些步骤做", Impact: "会调用工具并可能写入工件"},
			{ID: "no", Label: "取消", Description: "不执行", Impact: "不会改动任何东西"},
		},
	})
	if err != nil {
		return workflowOutcome{}, err
	}
	if resp.ChoiceID != "yes" {
		return workflowOutcome{Summary: "未确认，未执行"}, nil
	}
	return runner.run(rc, workflow.Launch{Def: def})
}

func parseWorkflowDef(raw string) (core.WorkflowDef, error) {
	s := stripFenceBlock(raw)
	start := strings.Index(s, "{")
	end := strings.LastIndex(s, "}")
	if start < 0 || end < start {
		return core.WorkflowDef{}, fmt.Errorf("workflow: 规划结果无法解析")
	}
	var def core.WorkflowDef
	if err := json.Unmarshal([]byte(s[start:end+1]), &def); err != nil {
		return core.WorkflowDef{}, fmt.Errorf("workflow: 规划结果无法解析")
	}
	if strings.TrimSpace(def.ID) == "" {
		def.ID = "dynamic"
	}
	if strings.TrimSpace(def.Title) == "" {
		def.Title = "临时工作流"
	}
	return def, nil
}

func planPreview(def core.WorkflowDef) string {
	var b strings.Builder
	fmt.Fprintf(&b, "按这个计划执行「%s」？\n", def.Title)
	for i, step := range def.Steps {
		fmt.Fprintf(&b, "%d. %s（%s）\n", i+1, step.Title, step.Kind)
	}
	return strings.TrimRight(b.String(), "\n")
}

func (w WorkflowRunner) Execute(rc RunCtx) error {
	src, ok := rc.(workflowSource)
	if !ok {
		return fmt.Errorf("workflow: 当前运行没有工作流定义")
	}
	launch, ok := src.Workflow()
	if !ok {
		return fmt.Errorf("workflow: 当前运行没有工作流定义")
	}
	res, err := w.run(rc, launch)
	if len(res.Parts) > 0 {
		_ = rc.SetAssistantParts(res.Parts)
	}
	return err
}

func (w WorkflowRunner) run(rc RunCtx, launch workflow.Launch) (workflowOutcome, error) {
	def := launch.Def
	vars := workflow.Vars{
		Input: currentUserText(rc),
		Slots: map[string]string{},
		Steps: map[string]string{},
	}
	for k, v := range launch.Slots {
		vars.Slots[k] = v
	}
	for _, missing := range launch.Missing {
		if rc.Context().Err() != nil {
			return workflowOutcome{}, rc.Context().Err()
		}
		resp, err := rc.AskHITL(core.HITLCard{
			Question: missing.Question, Kind: core.HITLKindInput, AllowFreeInput: true,
		})
		if err != nil {
			return workflowOutcome{}, err
		}
		answer := strings.TrimSpace(resp.FreeText)
		if answer == "" {
			answer = resp.ChoiceID
		}
		vars.Slots[missing.Key] = answer
	}

	plan := core.PlanSnapshot{Title: def.Title, Steps: make([]core.PlanStep, len(def.Steps))}
	for i, step := range def.Steps {
		plan.Steps[i] = core.PlanStep{ID: step.ID, Text: step.Title, Status: "pending"}
	}
	if err := rc.UpdatePlan(plan); err != nil {
		return workflowOutcome{}, err
	}

	wholeLeft := def.MaxRetries
	if wholeLeft <= 0 || wholeLeft > workflow.MaxWorkflowRetries {
		wholeLeft = workflow.MaxWorkflowRetries
	}
	var drops []string
	var arts []*core.ArtifactRef
	var prev string
	statuses := make([]string, len(def.Steps))
	for i := range def.Steps {
		if rc.Context().Err() != nil {
			return outcome(def, statuses, arts, drops, ""), rc.Context().Err()
		}
		step := def.Steps[i]
		plan.Steps[i].Status = "in_progress"
		if err := rc.UpdatePlan(plan); err != nil {
			return workflowOutcome{}, err
		}
		rendered, err := workflow.RenderStep(step, vars)
		if err != nil {
			return outcome(def, statuses, arts, drops, err.Error()), err
		}
		output, stepArts, reason, err := w.runStepWithCritic(rc, def, rendered, vars, prev, launch.Scripts, &wholeLeft, &drops)
		arts = append(arts, stepArts...)
		if err != nil {
			statuses[i] = "failed"
			plan.Steps[i].Status = "skipped"
			_ = rc.UpdatePlan(plan)
			res := outcome(def, statuses, arts, drops, reason)
			return res, err
		}
		vars.Steps[step.ID] = output
		prev = output
		statuses[i] = "done"
		plan.Steps[i].Status = "done"
		if err := rc.UpdatePlan(plan); err != nil {
			return workflowOutcome{}, err
		}
	}
	res := outcome(def, statuses, arts, drops, "")
	return res, nil
}

func (w WorkflowRunner) runStepWithCritic(rc RunCtx, def core.WorkflowDef, step core.WorkflowStep, vars workflow.Vars, prev string, scripts map[string]string, wholeLeft *int, drops *[]string) (string, []*core.ArtifactRef, string, error) {
	stepRetries := 1
	if step.Critic != nil && step.Critic.MaxRetries > 0 {
		stepRetries = step.Critic.MaxRetries
	}
	if stepRetries > workflow.MaxStepRetries {
		stepRetries = workflow.MaxStepRetries
	}
	used := 0
	note := ""
	var arts []*core.ArtifactRef
	for {
		current := step
		if note != "" && current.Prompt != "" {
			current.Prompt = current.Prompt + "\n\n未通过验收：" + note
		} else if note != "" {
			current.Prompt = "未通过验收：" + note
		}
		output, got, err := w.runWorkflowStep(rc, current, vars, prev, scripts)
		arts = append(arts, got...)
		if err != nil {
			return output, arts, err.Error(), err
		}
		if step.Critic == nil || strings.TrimSpace(step.Critic.Criteria) == "" {
			return output, arts, "", nil
		}
		verdict := w.judgeStep(rc, def.Title, step.Critic.Criteria, output)
		if verdict.Passed {
			return output, arts, "", nil
		}
		why := verdict.Reason
		if verdict.NextAction != "" {
			why += "。下一步：" + verdict.NextAction
		}
		*drops = append(*drops, step.ID+"："+why)
		if used >= stepRetries || *wholeLeft <= 0 {
			return output, arts, "步骤 " + step.Title + " 未通过验收：" + why, fmt.Errorf("workflow: 步骤 %s 未通过验收", step.ID)
		}
		used++
		*wholeLeft--
		note = why
	}
}

func (w WorkflowRunner) runWorkflowStep(rc RunCtx, step core.WorkflowStep, vars workflow.Vars, prev string, scripts map[string]string) (string, []*core.ArtifactRef, error) {
	switch step.Kind {
	case "prompt":
		return runPromptStep(rc, step)
	case "tool":
		res := rc.ExecuteTool(core.ToolCallRequest{Name: step.Tool, Arguments: step.Args})
		if res.Status == "error" {
			return res.Output, nil, fmt.Errorf("workflow: 工具 %s 失败：%s", step.Tool, res.Output)
		}
		var arts []*core.ArtifactRef
		if res.Artifact != nil {
			arts = append(arts, &core.ArtifactRef{ArtifactID: res.Artifact.ID, Name: res.Artifact.Name, Kind: res.Artifact.Kind})
		}
		return res.Output, arts, nil
	case "hitl":
		card := core.HITLCard{Question: step.Title, Kind: core.HITLKindInput, AllowFreeInput: true}
		if step.Hitl != nil {
			card.Question = step.Hitl.Question
			card.Kind = step.Hitl.Kind
			card.Choices = step.Hitl.Choices
			card.AllowFreeInput = step.Hitl.AllowFreeInput
			card.FreeInputHint = step.Hitl.FreeInputHint
		}
		resp, err := rc.AskHITL(card)
		if err != nil {
			return "", nil, err
		}
		if strings.TrimSpace(resp.FreeText) != "" {
			return strings.TrimSpace(resp.FreeText), nil, nil
		}
		return resp.ChoiceID, nil, nil
	case "artifact":
		content := step.Prompt
		if strings.TrimSpace(content) == "" {
			content = prev
		}
		name := step.Artifact
		if name == "" {
			name = step.ID + ".md"
		}
		art, err := rc.WriteArtifact(name, "document", "text/markdown", []byte(content))
		if err != nil {
			return "", nil, err
		}
		return string(art.ID), []*core.ArtifactRef{{ArtifactID: art.ID, Name: art.Name, Kind: art.Kind}}, nil
	case "card":
		card := core.ActivityCard{Title: step.Title, Kind: core.CardKindResult}
		if step.Card != nil {
			card.Kind = step.Card.Kind
			card.Title = step.Card.Title
			card.Tone = step.Card.Tone
			card.Body = step.Card.Body
			card.Actions = step.Card.Actions
		}
		created, err := rc.CreateCard(card)
		if err != nil {
			return "", nil, err
		}
		return string(created.ID), nil, nil
	case "script":
		return executeScriptStep(rc, w, step, scripts)
	default:
		return "", nil, fmt.Errorf("workflow: 未知步骤类型 %s", step.Kind)
	}
}

func runPromptStep(rc RunCtx, step core.WorkflowStep) (string, []*core.ArtifactRef, error) {
	agent := step.Agent
	if strings.TrimSpace(agent) == "" {
		agent = "general"
	}
	var res core.AgentResultPayload
	var err error
	if sp, ok := rc.(interface {
		SpawnAgent(agentID, name, task, hint string) (core.AgentResultPayload, error)
	}); ok {
		res, err = sp.SpawnAgent(subagentProfileID(agent), step.Title, step.Prompt, "")
	} else {
		res, err = rc.SpawnSubagent(step.Title, step.Prompt, "")
	}
	if err != nil {
		return "", nil, err
	}
	text := res.Text
	if text == "" {
		text = res.Summary
	}
	return text, artifactsIn(rc, text), nil
}

func artifactsIn(rc RunCtx, text string) []*core.ArtifactRef {
	var out []*core.ArtifactRef
	seen := map[string]bool{}
	for _, id := range gates.ArtifactIDPattern.FindAllString(text, -1) {
		if seen[id] {
			continue
		}
		art, _, ok := rc.Artifact(id)
		if !ok {
			continue
		}
		seen[id] = true
		out = append(out, &core.ArtifactRef{ArtifactID: art.ID, Name: art.Name, Kind: art.Kind})
	}
	return out
}

func (w WorkflowRunner) judgeStep(rc RunCtx, goal, criteria, output string) gates.Verdict {
	stream := w.JudgeStream
	model := "verify"
	if stream == nil {
		route := ResolveLightweightModel(rc.Profile(), rc.Settings())
		if route.Model == "" || route.Base == "" {
			return gates.Verdict{Passed: false, Reason: "验证器不可用", NextAction: "检查轻量模型配置"}
		}
		model = route.Model
		client := openLLMClient(route.Base, route.Key)
		stream = client.Stream
	}
	prompt := fmt.Sprintf("你是验收员。目标：%s\n验收标准：%s\n这一步的产出：\n%s\n标准里要求出现的句子，产出里必须逐字包含，否则 passed 必须为 false，nextAction 写出要补上的原句。只输出一个 JSON 对象，字段为 passed、reason、nextAction。", goal, criteria, output)
	var b strings.Builder
	for ev := range stream(rc.Context(), model, []agentllm.Message{{Role: agentllm.RoleUser, Content: prompt}}, nil, agentllm.StreamOptions{}) {
		switch ev.Kind {
		case agentllm.KindTextDelta:
			b.WriteString(ev.Text)
		case agentllm.KindError:
			return gates.Verdict{Passed: false, Reason: "验证器不可用", NextAction: "稍后再试"}
		case agentllm.KindMessageEnd:
			if b.Len() == 0 {
				b.WriteString(ev.Message.Content)
			}
		}
	}
	verdict, err := gates.ParseVerdict(b.String())
	if err != nil {
		return gates.Verdict{Passed: false, Reason: "无法解析", NextAction: "按验收标准重做"}
	}
	return verdict
}

func outcome(def core.WorkflowDef, statuses []string, arts []*core.ArtifactRef, drops []string, stopped string) workflowOutcome {
	var b strings.Builder
	title := def.Title
	if title == "" {
		title = def.ID
	}
	if stopped != "" {
		fmt.Fprintf(&b, "工作流「%s」停止：%s\n", title, stopped)
	} else {
		fmt.Fprintf(&b, "工作流「%s」完成。\n", title)
	}
	for i, step := range def.Steps {
		state := "pending"
		if i < len(statuses) && statuses[i] != "" {
			state = statuses[i]
		}
		fmt.Fprintf(&b, "- %s：%s\n", step.Title, state)
	}
	if len(arts) > 0 {
		b.WriteString("工件：")
		for i, art := range arts {
			if i > 0 {
				b.WriteString("、")
			}
			b.WriteString(string(art.ArtifactID))
		}
		b.WriteString("\n")
	}
	if len(drops) > 0 {
		b.WriteString("已丢弃：")
		b.WriteString(strings.Join(drops, "；"))
		b.WriteString("\n")
	}
	parts := []core.Part{{Type: core.PartText, Text: strings.TrimRight(b.String(), "\n")}}
	for _, art := range arts {
		parts = append(parts, core.Part{Type: core.PartArtifactRef, Artifact: art})
	}
	return workflowOutcome{Summary: parts[0].Text, Parts: parts, Artifacts: arts}
}

// stripFenceBlock 剥模型输出的 ``` 围栏（工作流定义解析用；与门禁域无关，本地持有）。
func stripFenceBlock(s string) string {
	s = strings.TrimSpace(s)
	if !strings.HasPrefix(s, "```") {
		return s
	}
	s = strings.TrimPrefix(s, "```")
	if i := strings.IndexByte(s, '\n'); i >= 0 {
		s = s[i+1:]
	}
	return strings.TrimSpace(strings.TrimSuffix(strings.TrimSpace(s), "```"))
}