package systemconfig

import (
	"encoding/json"
	"errors"

	"hfb_sys/backend/internal/model"

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

type Repository struct {
	db *gorm.DB
}

type AuditMeta struct {
	IP        string
	UserAgent string
}

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: "号主待确认归还超时分钟数"},
	{Key: "order.return_overdue_grace_minutes", Value: "10", Description: "租期到期后归还宽限分钟数"},
	{Key: "deposit.min_amount", Value: "50", Description: "发布租号最低押金"},
	{Key: "risk.sms_limit_per_phone_hour", Value: "5", Description: "单手机号每小时短信验证码次数"},
	{Key: "risk.sms_limit_per_ip_hour", Value: "20", Description: "单 IP 每小时短信验证码次数"},
	{Key: "realname.required_for_order", Value: "false", Description: "下单是否必须完成实名认证"},
	{Key: "settlement.platform_fee_rate", Value: "0.00", Description: "平台抽成比例"},
	{Key: "settlement.owner_cycle_days", Value: "0", Description: "号主结算周期天数"},
	{Key: "withdraw.min_amount", Value: "100", Description: "提现最低金额预留"},
}

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

func (r *Repository) List() ([]ConfigDTO, error) {
	if err := r.ensureDefaults(); err != nil {
		return nil, err
	}
	var rows []model.SystemConfig
	if err := r.db.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) Update(actorID uint64, key string, req UpdateRequest, meta AuditMeta) (*ConfigDTO, error) {
	var row model.SystemConfig
	err := r.db.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 := 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
		}
		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 (r *Repository) ensureDefaults() error {
	return r.db.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
			}
		}
		return nil
	})
}

func appendAuditLog(tx *gorm.DB, actorID uint64, action string, bizID uint64, meta AuditMeta, detail map[string]any) error {
	raw, err := json.Marshal(detail)
	if err != nil {
		return err
	}
	row := model.AuditLog{
		ActorType: "admin",
		ActorID:   actorID,
		Action:    action,
		BizType:   "system_config",
		BizID:     &bizID,
		IP:        meta.IP,
		UserAgent: meta.UserAgent,
		Detail:    datatypes.JSON(raw),
	}
	return tx.Create(&row).Error
}

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,
	}
}