package dialoguectx

import (
	"encoding/json"
	"fmt"
	"strings"
	"time"
	"unicode/utf8"
)

func renderTurnsMD(turns []RichDialogueTurn, from, to time.Time) string {
	var sb strings.Builder
	sb.WriteString("# 项目成员对话近窗（带元数据原文）\n\n")
	if len(turns) == 0 {
		sb.WriteString("本窗口内无授权可见的共享对话。\n")
		return sb.String()
	}
	sb.WriteString(fmt.Sprintf("- 覆盖窗口: %s → %s\n", from.Format("2006-01-02 15:04"), to.Format("2006-01-02 15:04")))
	sb.WriteString(fmt.Sprintf("- 条数: %d\n\n", len(turns)))
	for _, t := range turns {
		roleLabel := "用户"
		if t.Role == "assistant" {
			roleLabel = "助手"
		}
		identity := t.SpeakerName
		parts := make([]string, 0, 3)
		if t.SystemRole != "" {
			parts = append(parts, t.SystemRole)
		}
		if t.ProjectRole != "" {
			parts = append(parts, t.ProjectRole)
		}
		if t.DocDuty != "" {
			parts = append(parts, "duty:"+t.DocDuty)
		}
		if len(parts) > 0 {
			identity = fmt.Sprintf("%s(%s)", t.SpeakerName, strings.Join(parts, "/"))
		}
		stage := ""
		if t.StageKey != "" {
			stage = " stage=" + t.StageKey
		}
		sb.WriteString(fmt.Sprintf("[%s] %s %s:%s %s\n",
			t.CreatedAt.Format("2006-01-02 15:04"), identity, roleLabel, stage, t.Content))
	}
	return sb.String()
}

func renderDigestMD(turns []RichDialogueTurn, pkg *Package) string {
	var sb strings.Builder
	sb.WriteString("# 项目对话纪要\n\n")
	sb.WriteString("权威度：`collab_dialogue`（低于黑板事实与已批准文档；冲突时不得静默采信对话版本）\n\n")
	if pkg != nil {
		sb.WriteString(fmt.Sprintf("- 装配时间: %s\n", pkg.AssembledAt.Format(time.RFC3339)))
		sb.WriteString(fmt.Sprintf("- 纳入轮次: %d（私有排除 %d / 阶段不可见 %d / 噪声 %d）\n",
			pkg.TurnCount, pkg.ExcludedPrivate, pkg.ExcludedNoAccess, pkg.ExcludedNoise))
		if !pkg.CoveredFrom.IsZero() {
			sb.WriteString(fmt.Sprintf("- 覆盖窗口: %s → %s\n",
				pkg.CoveredFrom.Format("2006-01-02"), pkg.CoveredTo.Format("2006-01-02")))
		}
		sb.WriteString("\n")
	}
	if len(turns) == 0 {
		sb.WriteString("暂无可用共享对话纪要。\n")
		return sb.String()
	}

	// Day buckets: take first user utterance snippet per day as headline proxy.
	byDay := map[string][]string{}
	dayOrder := []string{}
	for _, t := range turns {
		day := t.DayKey
		if day == "" {
			day = t.CreatedAt.Format("2006-01-02")
		}
		if _, ok := byDay[day]; !ok {
			dayOrder = append(dayOrder, day)
		}
		if t.Role != "user" {
			continue
		}
		if len(byDay[day]) >= 3 {
			continue
		}
		byDay[day] = append(byDay[day], fmt.Sprintf("%s: %s", t.SpeakerName, truncateRunes(t.Content, 64)))
	}
	sb.WriteString("## 按日要点\n\n")
	for _, day := range dayOrder {
		pts := byDay[day]
		if len(pts) == 0 {
			sb.WriteString(fmt.Sprintf("- **%s**: （仅助手/系统可见消息）\n", day))
			continue
		}
		sb.WriteString(fmt.Sprintf("- **%s**: %s\n", day, strings.Join(pts, "；")))
	}
	out := sb.String()
	if utf8.RuneCountInString(out) > MaxDigestRunes {
		out = truncateRunes(out, MaxDigestRunes)
	}
	return out
}

// Known blackboard-style keys we try to extract from user utterances.
var factKeyPatterns = []struct {
	Key     string
	Markers []string
}{
	{"device_type", []string{"器械类型", "产品类型", "device_type", "设备类型"}},
	{"target_market", []string{"目标市场", "target_market", "市场定位"}},
	{"intended_use", []string{"预期用途", "intended_use", "适用场景"}},
	{"customer_name", []string{"客户名称", "客户是", "customer_name"}},
	{"budget", []string{"预算", "budget"}},
	{"classification", []string{"注册分类", "管理类别", "分类界定"}},
}

func extractFacts(turns []RichDialogueTurn) []DialogueFact {
	out := make([]DialogueFact, 0)
	seen := map[string]struct{}{}
	for _, t := range turns {
		if t.Role != "user" {
			continue
		}
		content := strings.TrimSpace(t.Content)
		for _, pat := range factKeyPatterns {
			val, ok := extractAfterMarker(content, pat.Markers)
			if !ok {
				continue
			}
			dedupe := pat.Key + "=" + val
			if _, exists := seen[dedupe]; exists {
				continue
			}
			seen[dedupe] = struct{}{}
			out = append(out, DialogueFact{
				Key:              pat.Key,
				Value:            val,
				SourceMessageID:  t.MessageID,
				SpeakerID:        t.SpeakerID,
				SpeakerName:      t.SpeakerName,
				StatedAt:         t.CreatedAt,
				Authority:        AuthorityCollabDialogue,
				ExplicitEvidence: strings.Contains(content, "材料") || strings.Contains(content, "〔") || strings.Contains(content, "决定"),
			})
		}
	}
	return out
}

func extractAfterMarker(content string, markers []string) (string, bool) {
	for _, m := range markers {
		idx := strings.Index(content, m)
		if idx < 0 {
			continue
		}
		rest := strings.TrimSpace(content[idx+len(m):])
		rest = strings.TrimLeft(rest, "：:=是为 ")
		rest = strings.TrimSpace(rest)
		if rest == "" {
			continue
		}
		// Cut at sentence boundary.
		for _, sep := range []string{"。", "；", ";", "\n", "，且", "并"} {
			if i := strings.Index(rest, sep); i > 0 {
				rest = rest[:i]
				break
			}
		}
		rest = truncateRunes(strings.TrimSpace(rest), 80)
		if rest == "" {
			continue
		}
		return rest, true
	}
	return "", false
}

// FactsJSON returns pretty-printed facts payload.
func FactsJSON(facts []DialogueFact) []byte {
	if facts == nil {
		facts = []DialogueFact{}
	}
	b, _ := json.MarshalIndent(facts, "", "  ")
	return b
}

// RenderAssistantSnippet builds a short MemoryComposer fragment (≤400 runes).
func RenderAssistantSnippet(pkg *Package) string {
	if pkg == nil || pkg.TurnCount == 0 {
		return ""
	}
	var sb strings.Builder
	sb.WriteString("【项目成员协同近况】（权威度低于黑板事实；冲突时以黑板为准）\n")
	// First ~3 digest day lines.
	lines := strings.Split(pkg.DigestMD, "\n")
	n := 0
	for _, line := range lines {
		line = strings.TrimSpace(line)
		if !strings.HasPrefix(line, "- **") {
			continue
		}
		sb.WriteString(line)
		sb.WriteString("\n")
		n++
		if n >= 3 {
			break
		}
	}
	if len(pkg.Facts) > 0 {
		sb.WriteString("- 对话沉淀事实候选: ")
		parts := make([]string, 0, 4)
		for i, f := range pkg.Facts {
			if i >= 4 {
				break
			}
			parts = append(parts, fmt.Sprintf("%s=%s（%s）", f.Key, f.Value, f.SpeakerName))
		}
		sb.WriteString(strings.Join(parts, "; "))
		sb.WriteString("\n")
	}
	out := sb.String()
	if utf8.RuneCountInString(out) > 400 {
		out = truncateRunes(out, 400)
	}
	return out
}