package newagentnode

import (
	"context"
	"fmt"
	"strings"
	"time"

	"github.com/google/uuid"

	newagentllm "github.com/LoveLosita/smartflow/backend/newAgent/llm"
	newagentmodel "github.com/LoveLosita/smartflow/backend/newAgent/model"
	newagentprompt "github.com/LoveLosita/smartflow/backend/newAgent/prompt"
	newagentstream "github.com/LoveLosita/smartflow/backend/newAgent/stream"
	"github.com/cloudwego/eino/schema"
)

const (
	planStageName        = "plan"
	planStatusBlockID    = "plan.status"
	planSpeakBlockID     = "plan.speak"
	planPinnedKey        = "current_plan"
	planCurrentStepKey   = "current_step"
	planCurrentStepTitle = "当前步骤"
	planFullPlanTitle    = "当前完整计划"
)

// PlanNodeInput 描述单轮规划节点执行所需的最小依赖。
type PlanNodeInput struct {
	RuntimeState        *newagentmodel.AgentRuntimeState
	ConversationContext *newagentmodel.ConversationContext
	UserInput           string
	Client              *newagentllm.Client
	ChunkEmitter        *newagentstream.ChunkEmitter
	ResumeNode          string
}

// RunPlanNode 执行一轮规划节点逻辑。
//
// 步骤说明：
//  1. 先校验最小依赖，并推送一条“正在规划”的状态，避免用户空等；
//  2. 再用 prompt/plan.go 组装 messages，请模型严格输出 PlanDecision JSON；
//  3. 若模型先对用户说了话，则先把 speak 伪流式推给前端，并写回 history；
//  4. 最后按 action 推进流程：
//     4.1 continue：继续停留在 planning；
//     4.2 ask_user：打开 pending interaction，后续交给 interrupt 收口；
//     4.3 plan_done：固化完整计划，刷新 pinned context，并进入 waiting_confirm。
func RunPlanNode(ctx context.Context, input PlanNodeInput) error {
	runtimeState, conversationContext, emitter, err := preparePlanNodeInput(input)
	if err != nil {
		return err
	}
	flowState := runtimeState.EnsureCommonState()

	// 1. 先发一条阶段状态，让前端知道当前已经进入规划环节。
	if err := emitter.EmitStatus(
		planStatusBlockID,
		planStageName,
		"planning",
		"正在梳理目标并补全执行计划。",
		false,
	); err != nil {
		return fmt.Errorf("规划阶段状态推送失败: %w", err)
	}

	// 2. 构造本轮规划输入，并要求模型输出结构化 PlanDecision。
	messages := newagentprompt.BuildPlanMessages(flowState, conversationContext, input.UserInput)
	decision, rawResult, err := newagentllm.GenerateJSON[newagentmodel.PlanDecision](
		ctx,
		input.Client,
		messages,
		newagentllm.GenerateOptions{
			Temperature: 0.2,
			MaxTokens:   1600,
			Thinking:    newagentllm.ThinkingModeEnabled,
			Metadata: map[string]any{
				"stage": planStageName,
			},
		},
	)
	if err != nil {
		if rawResult != nil && strings.TrimSpace(rawResult.Text) != "" {
			return fmt.Errorf("规划输出解析失败，原始输出=%s，错误=%w", strings.TrimSpace(rawResult.Text), err)
		}
		return fmt.Errorf("规划阶段模型调用失败: %w", err)
	}
	if err := decision.Validate(); err != nil {
		return fmt.Errorf("规划决策不合法: %w", err)
	}

	// 3. 若模型先对用户说了话，则先以伪流式推送，再写回 history，保证上下文连续。
	if strings.TrimSpace(decision.Speak) != "" {
		if err := emitter.EmitPseudoAssistantText(
			ctx,
			planSpeakBlockID,
			planStageName,
			decision.Speak,
			newagentstream.DefaultPseudoStreamOptions(),
		); err != nil {
			return fmt.Errorf("规划文案推送失败: %w", err)
		}
		conversationContext.AppendHistory(schema.AssistantMessage(decision.Speak, nil))
	}

	// 4. 按规划动作推进流程状态。
	switch decision.Action {
	case newagentmodel.PlanActionContinue:
		flowState.Phase = newagentmodel.PhasePlanning
		return nil
	case newagentmodel.PlanActionAskUser:
		question := resolvePlanAskUserText(decision)
		runtimeState.OpenAskUserInteraction(uuid.NewString(), question, strings.TrimSpace(input.ResumeNode))
		return nil
	case newagentmodel.PlanActionDone:
		// 4.1 直接把结构化 PlanStep 固化到 CommonState，避免 state 层丢失 done_when。
		// 4.2 再把完整自然语言计划写入 pinned context，保证后续 execute 优先看到。
		// 4.3 最后进入 waiting_confirm，等待用户确认整体计划。
		flowState.FinishPlan(decision.PlanSteps)
		writePlanPinnedBlocks(conversationContext, decision.PlanSteps)
		return nil
	default:
		return fmt.Errorf("未支持的规划动作: %s", decision.Action)
	}
}

func preparePlanNodeInput(input PlanNodeInput) (*newagentmodel.AgentRuntimeState, *newagentmodel.ConversationContext, *newagentstream.ChunkEmitter, error) {
	if input.RuntimeState == nil {
		return nil, nil, nil, fmt.Errorf("plan node: runtime state 不能为空")
	}
	if input.Client == nil {
		return nil, nil, nil, fmt.Errorf("plan node: plan client 未注入")
	}

	input.RuntimeState.EnsureCommonState()
	if input.ConversationContext == nil {
		input.ConversationContext = newagentmodel.NewConversationContext("")
	}
	if input.ChunkEmitter == nil {
		input.ChunkEmitter = newagentstream.NewChunkEmitter(newagentstream.NoopPayloadEmitter(), "", "", time.Now().Unix())
	}
	return input.RuntimeState, input.ConversationContext, input.ChunkEmitter, nil
}

func resolvePlanAskUserText(decision *newagentmodel.PlanDecision) string {
	if decision == nil {
		return "我还缺一点关键信息，想先向你确认一下。"
	}
	if strings.TrimSpace(decision.Speak) != "" {
		return strings.TrimSpace(decision.Speak)
	}
	if strings.TrimSpace(decision.Reason) != "" {
		return strings.TrimSpace(decision.Reason)
	}
	return "我还缺一点关键信息，想先向你确认一下。"
}

func writePlanPinnedBlocks(ctx *newagentmodel.ConversationContext, steps []newagentmodel.PlanStep) {
	if ctx == nil {
		return
	}

	fullPlanText := buildPinnedPlanText(steps)
	if strings.TrimSpace(fullPlanText) != "" {
		ctx.UpsertPinnedBlock(newagentmodel.ContextBlock{
			Key:     planPinnedKey,
			Title:   planFullPlanTitle,
			Content: fullPlanText,
		})
	}

	if len(steps) == 0 {
		return
	}

	firstStep := strings.TrimSpace(steps[0].Content)
	if strings.TrimSpace(steps[0].DoneWhen) != "" {
		firstStep = fmt.Sprintf("%s\n完成判定：%s", firstStep, strings.TrimSpace(steps[0].DoneWhen))
	}
	ctx.UpsertPinnedBlock(newagentmodel.ContextBlock{
		Key:     planCurrentStepKey,
		Title:   planCurrentStepTitle,
		Content: firstStep,
	})
}

func buildPinnedPlanText(steps []newagentmodel.PlanStep) string {
	if len(steps) == 0 {
		return ""
	}

	lines := make([]string, 0, len(steps))
	for i, step := range steps {
		content := strings.TrimSpace(step.Content)
		if content == "" {
			continue
		}

		line := fmt.Sprintf("%d. %s", i+1, content)
		if strings.TrimSpace(step.DoneWhen) != "" {
			line += fmt.Sprintf("\n完成判定：%s", strings.TrimSpace(step.DoneWhen))
		}
		lines = append(lines, line)
	}
	return strings.TrimSpace(strings.Join(lines, "\n\n"))
}