package distributionwithdrawal

import (
	"context"
	"time"

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

	approvalapp "github.com/break/junhong_cmp_fiber/internal/application/approval"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/auditcontext"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// QualificationApprovalHandler 将渠道无关企业微信终态应用到提现资料资格版本。
// 通过才使版本生效；驳回只标记该版本，不影响其他版本已记录的审批结果。
type QualificationApprovalHandler struct {
	db    *gorm.DB
	audit AuditWriter
}

// NewQualificationApprovalHandler 创建提现资料资格审批终态消费者。
func NewQualificationApprovalHandler(db *gorm.DB, audit AuditWriter) *QualificationApprovalHandler {
	return &QualificationApprovalHandler{db: db, audit: audit}
}

// Handle 幂等消费标准审批终态。
// 业务标识为资料版本主键；先锁定版本并校验审批实例一致，再以条件更新推进状态。
func (h *QualificationApprovalHandler) Handle(ctx context.Context, event approvalapp.TerminalDecisionEvent) error {
	if h == nil || h.db == nil || h.audit == nil {
		return errors.New(errors.CodeInternalError, "提现资料资格审批终态能力未配置")
	}
	if event.BusinessType != constants.ApprovalBusinessTypeWithdrawalQualification ||
		event.BusinessID == 0 || event.InstanceID == 0 {
		return errors.New(errors.CodeInvalidParam, "提现资料资格审批终态参数无效")
	}
	ctx = auditcontext.With(ctx, auditcontext.Context{
		CorrelationID: event.CorrelationID, ParentEventID: event.EventID,
	})
	return h.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		var version model.WithdrawalQualification
		if err := tx.WithContext(ctx).Clauses(clause.Locking{Strength: "UPDATE"}).
			First(&version, event.BusinessID).Error; err != nil {
			if err == gorm.ErrRecordNotFound {
				return errors.New(errors.CodeNotFound, "提现资料资格版本不存在")
			}
			return errors.Wrap(errors.CodeDatabaseError, err, "锁定提现资料资格版本失败")
		}
		if version.ApprovalInstanceID == nil || *version.ApprovalInstanceID != event.InstanceID {
			return errors.New(errors.CodeConflict, "提现资料资格版本关联的审批实例不一致")
		}
		if version.Status != constants.WithdrawalQualificationStatusPending {
			// 已是终态（含被替换或作废）：重复或乱序回调不再改变事实。
			return nil
		}
		// 店铺可能已被软删除：终态必须仍能收敛，不得把「店铺不存在」当成致命错误，
		// 否则该版本永久卡在待审批且终态事件永久重投。审计的店铺资源此时允许为空。
		shop := loadShopOrNil(ctx, tx, version.ShopID)
		before := qualificationAuditSnapshot(&version)
		switch event.Decision {
		case constants.ApprovalDecisionApproved:
			return h.applyApproved(ctx, tx, &version, shop, before, event)
		case constants.ApprovalDecisionRejected,
			constants.ApprovalDecisionCancelled,
			constants.ApprovalDecisionDeleted,
			constants.ApprovalDecisionRevokedAfterApproved:
			return h.applyRejected(ctx, tx, &version, shop, before, event)
		default:
			return errors.New(errors.CodeInvalidParam, "不支持的提现资料资格审批终态")
		}
	})
}

// applyApproved 使资料版本生效。
// 代理已提交替换版本时该版本已被失效，条件更新不再命中，不会覆盖更新版本。
func (h *QualificationApprovalHandler) applyApproved(
	ctx context.Context,
	tx *gorm.DB,
	version *model.WithdrawalQualification,
	shop *model.Shop,
	before map[string]any,
	event approvalapp.TerminalDecisionEvent,
) error {
	now := time.Now().UTC()
	if qualificationShopDisabled(ctx, tx, version.ShopID) {
		// 店铺停用或不存在时资格必须失效：若停留在待审批，则「有待审批版本」门禁会让该店铺
		// 永远无法获得有效资格（作废仅接受有效版本），因此就地收敛为已失效终态并写审计。
		return h.invalidateForDisabledShop(ctx, tx, version, before, event, now)
	}
	result := tx.WithContext(ctx).Model(&model.WithdrawalQualification{}).
		Where("id = ? AND status = ?", version.ID, constants.WithdrawalQualificationStatusPending).
		Updates(map[string]any{
			"status":     constants.WithdrawalQualificationStatusApproved,
			"decided_at": now, "updater": 0,
		})
	if result.Error != nil {
		return errors.Wrap(errors.CodeDatabaseError, result.Error, "使提现资料资格版本生效失败")
	}
	if result.RowsAffected != 1 {
		return errors.New(errors.CodeConflict, "提现资料资格版本状态已变化")
	}
	version.Status = constants.WithdrawalQualificationStatusApproved
	version.DecidedAt = &now
	return h.audit.WriteDistributionWithdrawal(ctx, tx, AuditChange{
		EventID:       "withdrawal-qualification:" + uintText(version.ID) + ":approved",
		ActionCode:    constants.AuditActionWithdrawalQualificationApproved,
		Summary:       "企业微信通过提现资料资格，版本已生效",
		CorrelationID: event.CorrelationID, Qualification: version, Shop: shop,
		BeforeData: before, AfterData: qualificationAuditSnapshot(version),
	})
}

// invalidateForDisabledShop 在店铺停用或不存在时把待审批资料版本收敛为已失效。
// 与代理停用联动失效语义一致（invalidated_by=0 表示系统联动），使该店铺可重新提交资格。
func (h *QualificationApprovalHandler) invalidateForDisabledShop(
	ctx context.Context,
	tx *gorm.DB,
	version *model.WithdrawalQualification,
	before map[string]any,
	event approvalapp.TerminalDecisionEvent,
	now time.Time,
) error {
	reason := "代理店铺已停用，资格自动失效"
	result := tx.WithContext(ctx).Model(&model.WithdrawalQualification{}).
		Where("id = ? AND status = ?", version.ID, constants.WithdrawalQualificationStatusPending).
		Updates(map[string]any{
			"status":         constants.WithdrawalQualificationStatusInvalidated,
			"invalid_reason": reason, "invalidated_at": now, "invalidated_by": 0,
			"decided_at": now, "updater": 0,
		})
	if result.Error != nil {
		return errors.Wrap(errors.CodeDatabaseError, result.Error, "失效停用店铺的提现资料资格失败")
	}
	if result.RowsAffected != 1 {
		return errors.New(errors.CodeConflict, "提现资料资格版本状态已变化")
	}
	version.Status = constants.WithdrawalQualificationStatusInvalidated
	version.InvalidReason = reason
	version.InvalidatedAt = &now
	version.InvalidatedBy = 0
	version.DecidedAt = &now
	return h.audit.WriteDistributionWithdrawal(ctx, tx, AuditChange{
		EventID:       "withdrawal-qualification:" + uintText(version.ID) + ":disabled",
		ActionCode:    constants.AuditActionWithdrawalQualificationInvalidated,
		Summary:       "企业微信通过时店铺已停用，提现资料资格直接失效",
		CorrelationID: event.CorrelationID, Qualification: version,
		BeforeData: before, AfterData: qualificationAuditSnapshot(version),
	})
}

// qualificationShopDisabled 判断资料版本所属店铺是否已停用或不存在。
func qualificationShopDisabled(ctx context.Context, tx *gorm.DB, shopID uint) bool {
	var enabled int64
	if err := tx.WithContext(ctx).Model(&model.Shop{}).
		Where("id = ? AND status = ?", shopID, constants.ShopStatusEnabled).
		Count(&enabled).Error; err != nil {
		return true
	}
	return enabled == 0
}

// applyRejected 标记资料版本已驳回，不影响其他版本已记录的审批结果。
func (h *QualificationApprovalHandler) applyRejected(
	ctx context.Context,
	tx *gorm.DB,
	version *model.WithdrawalQualification,
	shop *model.Shop,
	before map[string]any,
	event approvalapp.TerminalDecisionEvent,
) error {
	now := time.Now().UTC()
	result := tx.WithContext(ctx).Model(&model.WithdrawalQualification{}).
		Where("id = ? AND status = ?", version.ID, constants.WithdrawalQualificationStatusPending).
		Updates(map[string]any{
			"status":     constants.WithdrawalQualificationStatusRejected,
			"decided_at": now, "updater": 0,
		})
	if result.Error != nil {
		return errors.Wrap(errors.CodeDatabaseError, result.Error, "标记提现资料资格版本已驳回失败")
	}
	if result.RowsAffected != 1 {
		return errors.New(errors.CodeConflict, "提现资料资格版本状态已变化")
	}
	version.Status = constants.WithdrawalQualificationStatusRejected
	version.DecidedAt = &now
	return h.audit.WriteDistributionWithdrawal(ctx, tx, AuditChange{
		EventID:       "withdrawal-qualification:" + uintText(version.ID) + ":rejected",
		ActionCode:    constants.AuditActionWithdrawalQualificationRejected,
		Summary:       "企业微信未通过提现资料资格",
		CorrelationID: event.CorrelationID, Qualification: version, Shop: shop,
		BeforeData: before, AfterData: qualificationAuditSnapshot(version),
	})
}