package controllers

import (
	"doormile/constants"
	"doormile/internal/cxstage"
	"doormile/utils"

	"gorm.io/gorm"
)

// Per-order stages — the second half of §8.3.
//
// Stages 6-8 belong to each order rather than to the booking, and may differ
// between destinations of the same pickup: one parcel out for delivery in
// Chennai while another is still at a hub in Kerala. Each of the operational
// writes that moves a consignment records its customer stage against the
// destination that consignment belongs to, and the booking's own stage falls
// back to the least-advanced of them.

// cxStageForConsignmentStatus maps an operational consignment status onto the
// customer stage it means. Not every status has one: a parcel sitting on a
// tripsheet, or one flagged missing, is still "in transit" as far as the
// customer's seven milestones go, and inventing a stage for it would put a key
// on the wire the client silently falls back to `booked` for.
func cxStageForConsignmentStatus(status string) (string, bool) {
	switch status {
	case constants.ConsignmentInwardedAtHub,
		constants.ConsignmentTripsheetLoaded,
		constants.ConsignmentInTransit:
		return constants.CxStageInTransit, true
	case constants.ConsignmentOutForDelivery:
		return constants.CxStageOutForDelivery, true
	case constants.ConsignmentDelivered:
		return constants.CxStageDelivered, true
	default:
		// Created and Collected_By_Miler both mean "the order exists and is in
		// the rider's hands", which is order_created — already recorded at
		// pickup-complete, so there is nothing new to say.
		return "", false
	}
}

// recordCxConsignmentStage records the customer stage for one consignment,
// inside the caller's transaction, and returns the notification to fire once
// that transaction commits.
//
// The consignment is resolved to its destination through bookingdestinations,
// not through pickupbookings.consignmentid. That column names only the FIRST
// order of a multi-destination pickup, so a lookup through it finds nothing for
// destinations 2..N — which would mean no stage advance and no notification on
// every order after the first.
//
// A consignment that belongs to no customer booking at all — a console-created
// express shipment — is a no-op, not an error. Those have no customer app
// watching them.
func recordCxConsignmentStage(tx *gorm.DB, consignmentID int, status string, actorType string, actorID *int, source string) (afterCommit func(), err error) {
	noop := func() {}

	stage, ok := cxStageForConsignmentStatus(status)
	if !ok {
		return noop, nil
	}

	dest, booking, found := cxDestinationForConsignment(consignmentID)
	if !found || booking == nil {
		return noop, nil
	}
	if booking.Bookingsource != constants.BookingSourceCustomerApp {
		return noop, nil
	}

	destinationID := cxDestinationIDFor(dest)
	if err := cxstage.Record(tx, cxstage.Event{
		BookingID:     booking.Bookingid,
		DestinationID: destinationID,
		Stage:         stage,
		ActorType:     actorType,
		ActorID:       actorID,
		Source:        source,
		At:            utils.DBNow(),
	}); err != nil {
		return noop, err
	}

	bookingID := booking.Bookingid
	return func() { go cxstage.Notify(bookingID, destinationID, stage) }, nil
}

// cancelCxBookingFromOps stands a pickup down on behalf of a rider or an ops
// user, recording who did it and why.
//
// A customer whose pickup disappears with no explanation has no way to tell a
// cancellation from a bug, and support has no way to answer them — so the
// actor and the reason are part of the write, not an afterthought.
func cancelCxBookingFromOps(tx *gorm.DB, bookingID int, reason, actorType string, actorID *int, source string) error {
	if reason == "" {
		reason = "Cancelled by Doormile"
	}
	return cxstage.Cancel(tx, bookingID, reason, actorType, actorID, source)
}