// Package processlog 提供交易过程的追加式留痕能力。
package processlog

import (
	"encoding/json"
	"strconv"
	"strings"

	"hfb_sys/backend/internal/model"

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

const (
	ActorUser   = "user"
	ActorAdmin  = "admin"
	ActorSystem = "system"
)

type Entry struct {
	BusinessType string
	BusinessID   uint64
	Stage        string
	Action       string
	ActorType    string
	ActorID      uint64
	TargetType   string
	TargetID     *uint64
	Content      string
	Reason       string
	Payload      map[string]any
	Attachments  []string
	StateBefore  map[string]any
	StateAfter   map[string]any
}

func Append(tx *gorm.DB, entry Entry) error {
	actorName, err := displayName(tx, entry.ActorType, entry.ActorID)
	if err != nil {
		return err
	}
	targetName := ""
	if entry.TargetID != nil && *entry.TargetID > 0 {
		targetName, err = displayName(tx, entry.TargetType, *entry.TargetID)
		if err != nil {
			return err
		}
	}
	return tx.Create(&model.ProcessEvent{
		BusinessType:   entry.BusinessType,
		BusinessID:     entry.BusinessID,
		Stage:          entry.Stage,
		Action:         entry.Action,
		ActorType:      entry.ActorType,
		ActorID:        entry.ActorID,
		ActorName:      actorName,
		TargetType:     entry.TargetType,
		TargetID:       entry.TargetID,
		TargetName:     targetName,
		Content:        strings.TrimSpace(entry.Content),
		Reason:         strings.TrimSpace(entry.Reason),
		Payload:        jsonValue(entry.Payload),
		AttachmentURLs: jsonValue(entry.Attachments),
		StateBefore:    jsonValue(entry.StateBefore),
		StateAfter:     jsonValue(entry.StateAfter),
	}).Error
}

func List(tx *gorm.DB, businessType string, businessID uint64) ([]model.ProcessEvent, error) {
	var rows []model.ProcessEvent
	err := tx.Where("business_type = ? AND business_id = ?", businessType, businessID).
		Order("id ASC").Find(&rows).Error
	return rows, err
}

func displayName(tx *gorm.DB, actorType string, id uint64) (string, error) {
	if id == 0 || actorType == ActorSystem {
		return "系统", nil
	}
	switch actorType {
	case ActorAdmin:
		var row model.AdminUser
		if err := tx.Select("id", "username", "nickname").First(&row, id).Error; err != nil {
			if err == gorm.ErrRecordNotFound {
				return "客服 ID " + formatID(id), nil
			}
			return "", err
		}
		if strings.TrimSpace(row.Nickname) != "" {
			return row.Nickname + "（客服）", nil
		}
		if strings.TrimSpace(row.Username) != "" {
			return row.Username + "（客服）", nil
		}
		return "客服 ID " + formatID(id), nil
	default:
		var row model.User
		if err := tx.Select("id", "nickname", "phone").First(&row, id).Error; err != nil {
			if err == gorm.ErrRecordNotFound {
				return "用户 ID " + formatID(id), nil
			}
			return "", err
		}
		if strings.TrimSpace(row.Nickname) != "" {
			return row.Nickname + "（用户）", nil
		}
		if strings.TrimSpace(row.Phone) != "" {
			return row.Phone + "（用户）", nil
		}
		return "用户 ID " + formatID(id), nil
	}
}

func jsonValue(value any) datatypes.JSON {
	if value == nil {
		return datatypes.JSON([]byte("{}"))
	}
	raw, err := json.Marshal(value)
	if err != nil || len(raw) == 0 {
		return datatypes.JSON([]byte("{}"))
	}
	return datatypes.JSON(raw)
}

func formatID(id uint64) string {
	return strconv.FormatUint(id, 10)
}