package platform

import (
	"encoding/json"
	"errors"
	"time"

	"git.apinb.com/bsm-sdk/core/errcode"
	"git.apinb.com/bsm-sdk/core/infra"
	"git.apinb.com/bsm-sdk/core/middleware"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/impl"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/models"
	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

var errApprovalNotProcessable = errors.New("approval is not processable")

func approvalValues(status, opinion, operatorIdentity string) map[string]any {
	return map[string]any{
		"status":           status,
		"opinion":          opinion,
		"handler_identity": operatorIdentity,
		"handled_at":       time.Now().UTC(),
	}
}

// ApproveAudit records the reviewer and decision without allowing an approval
// to mutate any business fields. The operation audit is created atomically with
// the approval update.
func ApproveAudit(ctx *gin.Context) {
	claims, err := middleware.ParseAuth(ctx)
	if err != nil {
		infra.Response.Error(ctx, err)
		return
	}
	var request struct {
		Status  string `json:"status" binding:"required,max=32"`
		Opinion string `json:"opinion" binding:"max=2000"`
	}
	if err := ctx.ShouldBindJSON(&request); err != nil {
		infra.Response.Error(ctx, errcode.ErrInvalidArgument)
		return
	}
	if request.Status != "approved" && request.Status != "rejected" {
		infra.Response.Error(ctx, errcode.ErrInvalidArgument)
		return
	}

	values := approvalValues(request.Status, request.Opinion, claims.Identity)
	var approval models.AuditApproval
	err = impl.DBService.Transaction(func(transaction *gorm.DB) error {
		if err := transaction.Where("identity = ?", ctx.Param("identity")).First(&approval).Error; err != nil {
			return err
		}
		if approval.Status != "pending" || approval.ApplicantIdentity == claims.Identity {
			return errApprovalNotProcessable
		}
		before, err := json.Marshal(gin.H{
			"status": approval.Status, "opinion": approval.Opinion,
			"handler_identity": approval.HandlerIdentity, "handled_at": approval.HandledAt,
		})
		if err != nil {
			return err
		}
		if result := transaction.Model(&models.AuditApproval{}).Where("identity = ? AND status = ?", approval.Identity, "pending").Updates(values); result.Error != nil {
			return result.Error
		} else if result.RowsAffected == 0 {
			return errApprovalNotProcessable
		}
		after, err := json.Marshal(values)
		if err != nil {
			return err
		}
		return transaction.Create(&models.AuditOperationLog{
			Entity:           newEntity("enabled"),
			OperatorIdentity: claims.Identity,
			Action:           "approve",
			ObjectType:       "audit_approval",
			ObjectIdentity:   approval.Identity,
			BeforeData:       string(before),
			AfterData:        string(after),
		}).Error
	})
	if err != nil {
		if errors.Is(err, errApprovalNotProcessable) {
			infra.Response.Error(ctx, errcode.ErrInvalidArgument)
			return
		}
		if errors.Is(err, gorm.ErrRecordNotFound) {
			infra.Response.Error(ctx, errcode.ErrRecordNotFound)
			return
		}
		infra.Response.Error(ctx, err)
		return
	}
	approval.Status = request.Status
	approval.Opinion = request.Opinion
	approval.HandlerIdentity = claims.Identity
	handledAt := values["handled_at"].(time.Time)
	approval.HandledAt = &handledAt
	infra.Response.Success(ctx, resourceResponse(approval))
}