package runtime

import (
	"encoding/json"
	"fmt"
	"path/filepath"
	"strings"

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

const (
	// maxVerifyContinuations 与内核 Stop 的 3 次上限对齐。
	maxVerifyContinuations = 3
	// reminderToolGap 连续这么多个工具轮没有更新计划或待办，就提醒一次。
	reminderToolGap = 3
	// maxChecklistReminders 每个 run 最多提醒这么多次。
	maxChecklistReminders = 3
)

const verifyCapNotice = "本轮回复未通过终轮检查。"

const verifierUnavailableNotice = "本轮回复未通过独立验证（验证器不可用）"

const verifyFallbackPrompt = `你是独立验证器，不调用任何工具。根据用户要求、终轮回复、工具证据和工件清单判断这一轮是否已经完成。
拿不准时 passed 必须为 false。只输出一个 JSON 对象，不要写其他文字：{"passed":false,"reason":"为什么没通过","nextAction":"主模型下一步该做什么"}。`

type verifyVerdict struct {
	Passed     bool   `json:"passed"`
	Reason     string `json:"reason"`
	NextAction string `json:"nextAction"`
}

// checkDeliverables 确认本轮登记的工件存在且非空。
// md、txt、docx 还要过 quality；其他类型只检查存在与非空。
func checkDeliverables(rc RunCtx, refs []*core.ArtifactRef) []string {
	var reasons []string
	for _, ref := range refs {
		if ref == nil || ref.ArtifactID == "" {
			reasons = append(reasons, "工件引用缺少 ID")
			continue
		}
		art, content, ok := rc.Artifact(ref.ArtifactID)
		name := ref.Name
		if name == "" {
			name = string(ref.ArtifactID)
		}
		if !ok {
			reasons = append(reasons, name+" 不存在")
			continue
		}
		if art.Name != "" {
			name = art.Name
		}
		if len(content) == 0 {
			reasons = append(reasons, name+" 内容为空")
			continue
		}
		switch strings.ToLower(filepath.Ext(name)) {
		case ".md", ".txt", ".docx":
			report := quality.ScoreBytes(name, content)
			if !report.Passed {
				why := strings.Join(report.Violations, "；")
				if why == "" {
					why = "评分未通过"
				}
				reasons = append(reasons, name+"："+why)
			}
		}
	}
	return reasons
}

func (l *LLMRunner) runVerifier(rc RunCtx, body string, evidence []toolEvidence, refs []*core.ArtifactRef) (verifyVerdict, error) {
	route := ResolveLightweightModel(rc.Profile(), rc.Settings())
	stream := l.VerifyStream
	if stream == nil {
		if route.Model == "" || route.Base == "" {
			return verifyVerdict{}, fmt.Errorf("验证器调用失败")
		}
		client := &agentllm.Client{BaseURL: route.Base, APIKey: route.Key}
		stream = client.Stream
	}
	model := route.Model
	if model == "" {
		model = "verify"
	}
	msgs := []agentllm.Message{
		{Role: agentllm.RoleSystem, Content: l.verifyPrompt(rc.Profile().Owner)},
		{Role: agentllm.RoleUser, Content: evidencePrompt(currentUserText(rc), body, evidence, refs)},
	}
	var b strings.Builder
	for ev := range stream(rc.Context(), model, msgs, nil, agentllm.StreamOptions{}) {
		switch ev.Kind {
		case agentllm.KindTextDelta:
			b.WriteString(ev.Text)
		case agentllm.KindError:
			return verifyVerdict{}, fmt.Errorf("验证器调用失败")
		case agentllm.KindMessageEnd:
			if b.Len() == 0 {
				b.WriteString(ev.Message.Content)
			}
		}
	}
	verdict, err := parseVerdict(b.String())
	if err != nil {
		return verifyVerdict{}, fmt.Errorf("验证器返回无法解析")
	}
	return verdict, nil
}

func (l *LLMRunner) verifyPrompt(owner string) string {
	if l.Prompts != nil {
		if body, ok, err := l.Prompts.ModuleBody(owner, "aux.verify.final"); err == nil && ok && strings.TrimSpace(body) != "" {
			return body
		}
	}
	return verifyFallbackPrompt
}

func evidencePrompt(user, body string, evidence []toolEvidence, refs []*core.ArtifactRef) string {
	var b strings.Builder
	b.WriteString("用户要求：\n")
	if strings.TrimSpace(user) == "" {
		b.WriteString("（无）\n")
	} else {
		b.WriteString(user)
		b.WriteString("\n")
	}
	b.WriteString("\n终轮回复：\n")
	b.WriteString(body)
	b.WriteString("\n\n本轮工具：\n")
	if len(evidence) == 0 {
		b.WriteString("（无）\n")
	}
	for _, ev := range evidence {
		fmt.Fprintf(&b, "- %s %s %s\n", ev.Name, ev.Status, ev.Summary)
	}
	b.WriteString("\n本轮工件：\n")
	if len(refs) == 0 {
		b.WriteString("（无）\n")
	}
	for _, ref := range refs {
		if ref == nil {
			continue
		}
		fmt.Fprintf(&b, "- %s %s\n", ref.ArtifactID, ref.Name)
	}
	return b.String()
}

func parseVerdict(raw string) (verifyVerdict, error) {
	s := stripFence(raw)
	start := strings.Index(s, "{")
	end := strings.LastIndex(s, "}")
	if start < 0 || end < start {
		return verifyVerdict{}, fmt.Errorf("验证器返回无法解析")
	}
	s = s[start : end+1]
	var probe map[string]json.RawMessage
	if err := json.Unmarshal([]byte(s), &probe); err != nil {
		return verifyVerdict{}, err
	}
	if _, ok := probe["passed"]; !ok {
		return verifyVerdict{}, fmt.Errorf("验证器返回无法解析")
	}
	var verdict verifyVerdict
	if err := json.Unmarshal([]byte(s), &verdict); err != nil {
		return verifyVerdict{}, err
	}
	return verdict, nil
}

func stripFence(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:]
	}
	s = strings.TrimSpace(strings.TrimSuffix(strings.TrimSpace(s), "```"))
	return s
}

func (st *directRun) loadChecklist() {
	if src, ok := st.rc.(interface{ Todos() (core.TodoList, bool) }); ok {
		if list, ok := src.Todos(); ok {
			st.todos = list
		}
	}
	if src, ok := st.rc.(interface {
		Plan() (core.PlanSnapshot, bool)
	}); ok {
		if p, ok := src.Plan(); ok {
			st.plan = p
		}
	}
}

func (st *directRun) reminders(turn int) []string {
	if st.closedToolTurn {
		if st.checklistTouched {
			st.toolTurnsSince = 0
		} else {
			st.toolTurnsSince++
		}
		st.closedToolTurn = false
		st.checklistTouched = false
	}
	if st.toolTurnsSince < reminderToolGap || st.checklistReminders >= maxChecklistReminders {
		return nil
	}
	text := st.unfinishedReminder()
	if text == "" {
		return nil
	}
	st.toolTurnsSince = 0
	st.checklistReminders++
	return []string{text}
}

func (st *directRun) unfinishedReminder() string {
	var lines []string
	for _, item := range st.todos.Items {
		if item.Status == "done" {
			continue
		}
		text := strings.TrimSpace(item.Text)
		if text == "" {
			continue
		}
		lines = append(lines, "- 待办："+text)
	}
	for _, step := range st.plan.Steps {
		if step.Status == "done" || step.Status == "skipped" {
			continue
		}
		text := strings.TrimSpace(step.Text)
		if text == "" {
			continue
		}
		lines = append(lines, "- 计划："+text)
	}
	if len(lines) == 0 {
		return ""
	}
	return "计划和待办已连续 3 个工具轮没有更新。未完成项：\n" + strings.Join(lines, "\n") + "\n请更新计划或待办，或在回复里说明为什么先不做。"
}