// 2020 Rackspace, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.

package status

import "github.rackspace.com/DCM/gomigrate/shared"

var (
	// OrderedPaths is the collection of all upgrade paths that can be taken, ordered by
	// priority, with the first path matching being used as the upgrade path.
	OrderedPaths = []Path{
		PathStd,
	}

	// PathStd is the scenario where we are upgrading through the standard
	// device upgrade/downgrade path
	PathStd = Path{
		-1, // "Computer No Longer Active",
		1,  // "Order Submitted",
		3,  // "Received Contract",
		63, // "Sent to Production",
		4,  // "In Assembly",
		5,  // "Ready for QC",
		6,  // "QC Complete/Ready to Rack",
		64, // "Racked",
		9,  // "Segment Configuration",
		12, // "Online/Complete",
	}

	// PathDeploymentOC is the path that devices can take if the Datapipe deployment sku
	// exist on the device and final status is Online/Complete
	PathDeploymentOC = Path{
		-1, // "Computer No Longer Active",
		1,  // "Order Submitted",
		11, // "Provisioning",
		12, // "Online/Complete",
	}

	// PathDeploymentSM is the path that devices can take if the Datapipe deployment sku
	// exist on the device and final status is Support Maintenance
	PathDeploymentSM = Path{
		-1, // "Computer No Longer Active",
		1,  // "Order Submitted",
		11, // "Provisioning",
		70, // "Support Maintenance",
	}
)

// Path is a package specific type that will be used to execute helper methods on
type Path []int

// Reverse will reverse the index order of the upgade/downgrade paths
func (p Path) Reverse() {
	for i, j := 0, len(p)-1; i < j; i, j = i+1, j-1 {
		p[i], p[j] = p[j], p[i]
	}
}

// Index will find the index value in the path for the given value
func (p Path) Index(value int) int {
	for i := range p {
		if p[i] == value {
			return i
		}
	}
	return -1
}

// ValidPath will return a bool if both the source and destination statuses exist in the
// upgrade path, making it an eligible candidate.
func (p Path) ValidPath(sourceStatus, destinationStatus int) bool {
	return shared.IntInSlice(sourceStatus, p) && shared.IntInSlice(destinationStatus, p)
}

// Steps will return the list of statuses we need to walk through, minus the statuses that
// are already excluded due to the current and destination statuses.
func (p Path) Steps(sourceStatus, destinationStatus int) []int {
	r := p
	// If we need to downgrade as opposed to upgrade
	if r.Index(destinationStatus) < r.Index(sourceStatus) {
		r.Reverse()
	}

	r = r[r.Index(sourceStatus)+1:]
	r = r[:r.Index(destinationStatus)+1]
	return r
}