package systemconfig

import (
	"context"
	"encoding/json"
	"errors"
	"strings"
	"sync"
	"unicode/utf8"

	"hfb_sys/backend/internal/auditlog"
	"hfb_sys/backend/internal/model"
	"hfb_sys/backend/internal/modules/rentergrowth"
	smsnode "hfb_sys/backend/internal/modules/sms"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

type Repository struct {
	db          *gorm.DB
	initMu      sync.RWMutex
	initialized bool
}

type AuditMeta = auditlog.Meta

type defaultConfig struct {
	Key         string
	Value       string
	Description string
}

var defaultConfigs = []defaultConfig{
	{Key: "handoff.owner_submit_timeout_minutes", Value: "30", Description: "号主待交接超时分钟数"},
	{Key: "handoff.renter_confirm_timeout_minutes", Value: "30", Description: "租客待确认收号超时分钟数"},
	{Key: "handoff.owner_return_confirm_timeout_minutes", Value: "120", Description: "号主待确认结账超时分钟数"},
	{Key: "order.pending_payment_timeout_minutes", Value: "15", Description: "订单待支付超时取消分钟数"},
	{Key: "order.return_overdue_grace_minutes", Value: "10", Description: "预计截止后结账宽限分钟数"},
	{Key: "listing.review_required", Value: "false", Description: "发布账号是否需要后台人工审核"},
	{Key: "listing.publish_cooldown_minutes", Value: "5", Description: "同一用户两次新增发布账号的最小间隔分钟数（0 表示关闭）"},
	{Key: listingPublishAgreementsConfigKey, Value: defaultListingPublishAgreementsConfigValue(), Description: "发布账号前协议配置 JSON"},
	{Key: orderAgreementsConfigKey, Value: defaultOrderAgreementsConfigValue(), Description: "下单前协议配置 JSON"},
	{Key: postRentalNoticeConfigKey, Value: defaultPostRentalNoticeConfigValue(), Description: "租后须知配置 JSON"},
	{Key: rentergrowth.ConfigKey, Value: rentergrowth.DefaultConfigValue(), Description: "租客成长等级规则（积分门槛、租金折扣、等级免押额度）"},
	{Key: smsnode.ConfigKey, Value: smsnode.DefaultConfigValue(), Description: "节点短信模板配置（总开关、各业务节点模板 CODE）"},
	{Key: "chat.default_support_admin_id", Value: "2", Description: "默认客服 ID（必须是启用状态的客服角色）"},
	{Key: "chat.auto_welcome_message", Value: "欢迎加入订单群聊！如有任何问题，请随时沟通。", Description: "建群后自动发送的欢迎话术"},
	{Key: "chat.listing_group_welcome", Value: "欢迎加入账号群！请号主扫描下方二维码加入企业微信群，方便客服与您及时联系。", Description: "发布群创建后自动发送的欢迎语"},
	{Key: "chat.renter_retention_days_after_order_end", Value: "5", Description: "订单结束后租客保留在发布群的天数（3-7）"},
	{Key: "integration.paddle_ocr_token", Value: "", Description: "PaddleOCR API Token，用于二维码群名自动识别"},
	{Key: "integration.paddle_ocr_job_url", Value: "https://paddleocr.aistudio-app.com/api/v2/ocr/jobs", Description: "PaddleOCR 异步任务接口地址"},
	{Key: "integration.paddle_ocr_model", Value: "PP-OCRv6", Description: "PaddleOCR 识别模型（默认 PP-OCRv6，支持 PaddleOCR-VL-1.6 等）"},
	{Key: homeAnnouncementsConfigKey, Value: defaultHomeAnnouncementsConfigValue(), Description: "移动端首页公告 JSON 数组"},
	{Key: homeBannersConfigKey, Value: defaultHomeBannersConfigValue(), Description: "移动端首页轮播图 JSON 数组"},
	{Key: awRecycleConfigKey, Value: defaultAWRecycleConfigValue(), Description: "首页 AW炫彩回收入口配置 JSON（标题/副标题/展示图片）"},
	{Key: cooperationFeedbackConfigKey, Value: defaultCooperationFeedbackConfigValue(), Description: "首页 合作与反馈入口配置 JSON（标题/副标题/展示图片）"},
	{Key: homeEntriesEnabledConfigKey, Value: defaultHomeEntriesEnabledConfigValue(), Description: "首页 AW炫彩回收/合作与反馈入口总开关（关闭后 PC/移动端均隐藏）"},
	{Key: publishOptionsConfigKey, Value: defaultPublishOptionsConfigValue(), Description: "发布页选项配置 JSON"},
	{Key: salePriceConfigKey, Value: defaultSalePriceConfigValue(), Description: "内部出售定价规则 JSON"},
	{Key: DistributionSettlementHoldDaysKey, Value: defaultDistributionSettlementHoldDaysValue(), Description: "新建分销站点默认结算冷却天数（0=立即释放，最大 365）"},
	{Key: "backup.schedule_enabled", Value: "true", Description: "在线备份定时任务是否启用"},
	{Key: "backup.full_hour", Value: "4", Description: "每日全量备份小时（Asia/Shanghai）"},
	{Key: "backup.full_minute", Value: "30", Description: "每日全量备份分钟（Asia/Shanghai）"},
	{Key: "backup.binlog_interval_minutes", Value: "1", Description: "binlog 归档间隔分钟（1-5）"},
}

var adminVisibleConfigKeys = []string{
	"chat.auto_welcome_message",
	"chat.default_support_admin_id",
	"chat.listing_group_welcome",
	"chat.renter_retention_days_after_order_end",
	"distribution.default_settlement_hold_days",
	"handoff.owner_return_confirm_timeout_minutes",
	"handoff.owner_submit_timeout_minutes",
	"handoff.renter_confirm_timeout_minutes",
	"integration.paddle_ocr_job_url",
	"integration.paddle_ocr_model",
	"integration.paddle_ocr_token",
	"listing.publish_agreements",
	"listing.publish_cooldown_minutes",
	"listing.publish_options",
	"listing.review_required",
	"listing.sale_price_config",
	"mobile.home_announcements",
	"mobile.home_banners",
	"mobile.aw_recycle",
	"mobile.cooperation_feedback",
	"mobile.home_entries_enabled",
	"order.agreements",
	"order.pending_payment_timeout_minutes",
	"order.return_overdue_grace_minutes",
	"profile.post_rental_notice",
	"renter.growth_level_rules",
	"sms.business_templates",
}

func NewRepository(db *gorm.DB) *Repository {
	return &Repository{db: db}
}

// EnsureDefaults 仅在服务启动或首次访问时初始化默认系统配置。
// 使用读写锁保证进程生命周期内只真正落库初始化一次，避免每个读请求重复开事务写锁争抢。
func (r *Repository) EnsureDefaults(ctx context.Context) error {
	r.initMu.RLock()
	if r.initialized {
		r.initMu.RUnlock()
		return nil
	}
	r.initMu.RUnlock()

	r.initMu.Lock()
	defer r.initMu.Unlock()
	if r.initialized {
		return nil
	}
	if err := r.ensureDefaults(ctx); err != nil {
		return err
	}
	r.initialized = true
	return nil
}

func (r *Repository) List(ctx context.Context) ([]ConfigDTO, error) {
	if err := r.EnsureDefaults(ctx); err != nil {
		return nil, err
	}
	var rows []model.SystemConfig
	if err := r.db.WithContext(ctx).Where("`key` IN ?", adminVisibleConfigKeys).Order("`key` ASC").Find(&rows).Error; err != nil {
		return nil, err
	}
	items := make([]ConfigDTO, 0, len(rows))
	for _, row := range rows {
		items = append(items, toDTO(row))
	}
	return items, nil
}

func (r *Repository) FindValue(ctx context.Context, key string) (string, error) {
	if err := r.EnsureDefaults(ctx); err != nil {
		return "", err
	}
	var row model.SystemConfig
	if err := r.db.WithContext(ctx).Where("`key` = ?", key).First(&row).Error; err != nil {
		return "", err
	}
	return row.Value, nil
}

func (r *Repository) Update(ctx context.Context, actorID uint64, key string, req UpdateRequest, meta AuditMeta) (*ConfigDTO, error) {
	if err := validateConfigValue(key, req.Value); err != nil {
		return nil, err
	}
	var row model.SystemConfig
	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).Where("`key` = ?", key).First(&row).Error; err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				row = model.SystemConfig{
					Key:         key,
					Value:       req.Value,
					Description: req.Description,
					UpdatedBy:   &actorID,
				}
				if err := tx.Create(&row).Error; err != nil {
					return err
				}
			} else {
				return err
			}
		} else {
			before := row.Value
			row.Value = req.Value
			if req.Description != "" {
				row.Description = req.Description
			}
			row.UpdatedBy = &actorID
			if err := tx.Save(&row).Error; err != nil {
				return err
			}
			if err := syncRenterGrowthLevels(tx, key, req.Value); err != nil {
				return err
			}
			if err := appendAuditLog(tx, actorID, "system_config.update", row.ID, meta, map[string]any{
				"key":    row.Key,
				"before": before,
				"after":  row.Value,
			}); err != nil {
				return err
			}
			return nil
		}
		if err := syncRenterGrowthLevels(tx, key, req.Value); err != nil {
			return err
		}
		return appendAuditLog(tx, actorID, "system_config.create", row.ID, meta, map[string]any{
			"key":   row.Key,
			"value": row.Value,
		})
	})
	if err != nil {
		return nil, err
	}
	dto := toDTO(row)
	return &dto, nil
}

func syncRenterGrowthLevels(tx *gorm.DB, key string, value string) error {
	if key != rentergrowth.ConfigKey {
		return nil
	}
	cfg, err := rentergrowth.ParseConfigValue(value)
	if err != nil {
		return err
	}
	return rentergrowth.SyncAllUserLevels(tx, cfg)
}

func (r *Repository) ensureDefaults(ctx context.Context) error {
	return r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		for _, item := range defaultConfigs {
			row := model.SystemConfig{
				Key:         item.Key,
				Value:       item.Value,
				Description: item.Description,
			}
			if err := tx.Clauses(clause.OnConflict{DoNothing: true}).Create(&row).Error; err != nil {
				return err
			}
			if item.Key == "chat.default_support_admin_id" {
				if err := updateDefaultSupportConfig(tx, item); err != nil {
					return err
				}
			}
			if item.Key == "chat.listing_group_welcome" {
				if err := updateLegacyListingGroupWelcome(tx, item); err != nil {
					return err
				}
			}
			if item.Key == publishOptionsConfigKey {
				if err := updateLegacyPublishOptions(tx, item); err != nil {
					return err
				}
			}
		}
		return nil
	})
}

func updateLegacyListingGroupWelcome(tx *gorm.DB, item defaultConfig) error {
	var row model.SystemConfig
	if err := tx.Where("`key` = ?", item.Key).First(&row).Error; err != nil {
		return err
	}
	changed := false
	if isMojibakeText(row.Value) {
		row.Value = item.Value
		changed = true
	}
	if row.Description != item.Description {
		row.Description = item.Description
		changed = true
	}
	if !changed {
		return nil
	}
	return tx.Save(&row).Error
}

func updateDefaultSupportConfig(tx *gorm.DB, item defaultConfig) error {
	var row model.SystemConfig
	if err := tx.Where("`key` = ?", item.Key).First(&row).Error; err != nil {
		return err
	}
	changed := false
	if strings.TrimSpace(row.Value) == "1" {
		row.Value = item.Value
		changed = true
	}
	if row.Description != item.Description {
		row.Description = item.Description
		changed = true
	}
	if !changed {
		return nil
	}
	return tx.Save(&row).Error
}

func updateLegacyPublishOptions(tx *gorm.DB, item defaultConfig) error {
	var row model.SystemConfig
	if err := tx.Where("`key` = ?", item.Key).First(&row).Error; err != nil {
		return err
	}
	normalized, err := normalizePublishOptionsValue(row.Value)
	if err != nil {
		normalized = item.Value
	}
	changed := row.Value != normalized || row.Description != item.Description
	row.Value = normalized
	row.Description = item.Description
	if !changed {
		return nil
	}
	return tx.Save(&row).Error
}

func applyConditionalBanEvidenceDefault(options *PublishOptionsDTO) {
	defaults := DefaultPublishOptions()
	defaultSlots := make(map[string]PublishScreenshotSlot, len(defaults.ScreenshotSlots))
	for _, item := range defaults.ScreenshotSlots {
		defaultSlots[item.Key] = item
	}
	for index, item := range options.ScreenshotSlots {
		if item.Key != "tencentSecurity" {
			continue
		}
		if next, ok := defaultSlots[item.Key]; ok {
			options.ScreenshotSlots[index] = next
		}
	}
}

func normalizePublishOptionsValue(value string) (string, error) {
	value = repairMojibakeJSON(value)
	var options PublishOptionsDTO
	if err := json.Unmarshal([]byte(value), &options); err != nil {
		return "", err
	}
	var fields map[string]json.RawMessage
	if err := json.Unmarshal([]byte(value), &fields); err != nil {
		return "", err
	}
	if options.SchemaVersion < publishOptionsSchemaVersion {
		if hasLegacyPublishQuantityItem(options.QuantityItems) {
			options = DefaultPublishOptions()
		} else {
			normalizePublishOptions(&options)
			if _, ok := fields["ban_record_options"]; !ok {
				applyConditionalBanEvidenceDefault(&options)
			}
		}
	} else {
		normalizePublishOptions(&options)
	}
	options.SchemaVersion = publishOptionsSchemaVersion
	raw, err := json.Marshal(options)
	if err != nil {
		return "", err
	}
	return string(raw), nil
}

func hasLegacyPublishQuantityItem(items []PublishQuantityItem) bool {
	for _, item := range items {
		if item.Key == "kit5" {
			return true
		}
	}
	return false
}

// repairMojibakeJSON 先按整段 JSON 还原；整段不是纯乱码时，再逐个字符串字段尝试还原。
func repairMojibakeJSON(value string) string {
	if decoded, ok := decodeCP1252Mojibake(value); ok {
		return decoded
	}
	var root any
	if err := json.Unmarshal([]byte(value), &root); err != nil {
		return value
	}
	repaired, changed := repairMojibakeValue(root)
	if !changed {
		return value
	}
	raw, err := json.Marshal(repaired)
	if err != nil {
		return value
	}
	return string(raw)
}

func repairMojibakeValue(value any) (any, bool) {
	switch current := value.(type) {
	case string:
		if decoded, ok := decodeCP1252Mojibake(current); ok {
			return decoded, true
		}
		return current, false
	case []any:
		changed := false
		for index := range current {
			next, updated := repairMojibakeValue(current[index])
			if updated {
				current[index] = next
				changed = true
			}
		}
		return current, changed
	case map[string]any:
		changed := false
		for key, item := range current {
			next, updated := repairMojibakeValue(item)
			if updated {
				current[key] = next
				changed = true
			}
		}
		return current, changed
	default:
		return value, false
	}
}

// decodeCP1252Mojibake 把「UTF-8 字节被当作 CP1252/Latin-1 字符」的文本还原为原始 UTF-8。
// 普通中文包含 CP1252 无法表示的字符，会直接判定失败；纯 ASCII 也不会误判。
func decodeCP1252Mojibake(value string) (string, bool) {
	if value == "" {
		return "", false
	}
	raw := make([]byte, 0, len(value))
	sawNonASCII := false
	for _, char := range value {
		next, ok := cp1252Byte(char)
		if !ok {
			return "", false
		}
		if next >= 0x80 {
			sawNonASCII = true
		}
		raw = append(raw, next)
	}
	if !sawNonASCII || !utf8.Valid(raw) {
		return "", false
	}
	decoded := string(raw)
	if decoded == value {
		return "", false
	}
	// 只接受能还原出汉字的候选，避免把正常的西文重音字符误判为乱码。
	if !containsHan(decoded) {
		return "", false
	}
	return decoded, true
}

func containsHan(value string) bool {
	for _, char := range value {
		if char >= 0x4E00 && char <= 0x9FFF {
			return true
		}
	}
	return false
}

// cp1252HighRunes 是 CP1252 中 0x80-0x9F 对应的 Unicode 字符；
// 其余可映射字符与 Latin-1 一致。
var cp1252HighRunes = [32]rune{
	0x20AC, 0x0081, 0x201A, 0x0192, 0x201E, 0x2026, 0x2020, 0x2021,
	0x02C6, 0x2030, 0x0160, 0x2039, 0x0152, 0x008D, 0x017D, 0x008F,
	0x0090, 0x2018, 0x2019, 0x201C, 0x201D, 0x2022, 0x2013, 0x2014,
	0x02DC, 0x2122, 0x0161, 0x203A, 0x0153, 0x009D, 0x017E, 0x0178,
}

func cp1252Byte(char rune) (byte, bool) {
	if char <= 0xFF {
		return byte(char), true
	}
	for offset, candidate := range cp1252HighRunes {
		if char == candidate {
			return byte(0x80 + offset), true
		}
	}
	return 0, false
}

func isMojibakeText(value string) bool {
	_, ok := decodeCP1252Mojibake(value)
	return ok
}

func appendAuditLog(tx *gorm.DB, actorID uint64, action string, bizID uint64, meta AuditMeta, detail map[string]any) error {
	return auditlog.Append(tx, auditlog.Entry{
		ActorType: "admin",
		ActorID:   actorID,
		Action:    action,
		BizType:   "system_config",
		BizID:     &bizID,
		Meta:      meta,
		Detail:    detail,
	})
}

func toDTO(row model.SystemConfig) ConfigDTO {
	return ConfigDTO{
		ID:          row.ID,
		Key:         row.Key,
		Value:       row.Value,
		Description: row.Description,
		UpdatedBy:   row.UpdatedBy,
		CreatedAt:   row.CreatedAt,
		UpdatedAt:   row.UpdatedAt,
	}
}