// Copyright 2015 clair authors
//
// 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 database

import (
	"github.com/coreos/clair/utils"
	cerrors "github.com/coreos/clair/utils/errors"
	"github.com/coreos/clair/utils/types"
	"github.com/google/cayley"
	"github.com/google/cayley/graph"
	"github.com/google/cayley/graph/path"
)

const (
	FieldVulnerabilityID          = "id"
	FieldVulnerabilityLink        = "link"
	FieldVulnerabilityPriority    = "priority"
	FieldVulnerabilityDescription = "description"
	FieldVulnerabilityFixedIn     = "fixedIn"
	// FieldVulnerabilityCausedByPackage only makes sense with FindAllVulnerabilitiesByFixedIn.
	FieldVulnerabilityCausedByPackage = "causedByPackage"

	// This field is not selectable and is for internal use only.
	fieldVulnerabilityIsValue = "vulnerability"
)

var FieldVulnerabilityAll = []string{FieldVulnerabilityID, FieldVulnerabilityLink, FieldVulnerabilityPriority, FieldVulnerabilityDescription, FieldVulnerabilityFixedIn}

// Vulnerability represents a vulnerability that is fixed in some Packages
type Vulnerability struct {
	Node         string `json:"-"`
	ID           string
	Link         string
	Priority     types.Priority
	Description  string   `json:",omitempty"`
	FixedInNodes []string `json:"-"`

	CausedByPackage string `json:",omitempty"`
}

// GetNode returns an unique identifier for the graph node
// Requires the key field: ID
func (v *Vulnerability) GetNode() string {
	return fieldVulnerabilityIsValue + ":" + utils.Hash(v.ID)
}

// ToAbstractVulnerability converts a Vulnerability into an
// AbstractVulnerability.
func (v *Vulnerability) ToAbstractVulnerability() (*AbstractVulnerability, error) {
	// Find FixedIn packages.
	fixedInPackages, err := FindAllPackagesByNodes(v.FixedInNodes, []string{FieldPackageOS, FieldPackageName, FieldPackageVersion})
	if err != nil {
		return nil, err
	}

	return &AbstractVulnerability{
		ID:               v.ID,
		Link:             v.Link,
		Priority:         v.Priority,
		Description:      v.Description,
		AffectedPackages: PackagesToAbstractPackages(fixedInPackages),
	}, nil
}

// AbstractVulnerability represents a Vulnerability as it is defined in the database
// package but exposes directly a list of AbstractPackage instead of
// nodes to packages.
type AbstractVulnerability struct {
	ID               string
	Link             string
	Priority         types.Priority
	Description      string
	AffectedPackages []*AbstractPackage
}

// ToVulnerability converts an abstractVulnerability into
// a Vulnerability
func (av *AbstractVulnerability) ToVulnerability(fixedInNodes []string) *Vulnerability {
	return &Vulnerability{
		ID:           av.ID,
		Link:         av.Link,
		Priority:     av.Priority,
		Description:  av.Description,
		FixedInNodes: fixedInNodes,
	}
}

// InsertVulnerabilities inserts or updates several vulnerabilities in the database in one transaction
// During an update, if the vulnerability was previously fixed by a version in a branch and a new package of that branch is specified, the previous one is deleted
// Otherwise, it simply adds the defined packages, there is currently no way to delete affected packages.
//
// ID, Link, Priority and FixedInNodes fields have to be specified. Description is optionnal.
func InsertVulnerabilities(vulnerabilities []*Vulnerability) ([]Notification, error) {
	if len(vulnerabilities) == 0 {
		return []Notification{}, nil
	}

	// Create required data structure
	var err error
	t := cayley.NewTransaction()
	cachedVulnerabilities := make(map[string]*Vulnerability)

	var notifications []Notification
	newVulnerabilityNotifications := make(map[string]*NewVulnerabilityNotification)
	vulnerabilityPriorityIncreasedNotifications := make(map[string]*VulnerabilityPriorityIncreasedNotification)
	vulnerabilityPackageChangedNotifications := make(map[string]*VulnerabilityPackageChangedNotification)

	// Iterate over all the vulnerabilities we need to insert/update
	for _, vulnerability := range vulnerabilities {
		// Check if the vulnerability already exists
		existingVulnerability, _ := cachedVulnerabilities[vulnerability.ID]
		if existingVulnerability == nil {
			existingVulnerability, err = FindOneVulnerability(vulnerability.ID, FieldVulnerabilityAll)
			if err != nil && err != cerrors.ErrNotFound {
				return []Notification{}, err
			}
			if existingVulnerability != nil {
				cachedVulnerabilities[vulnerability.ID] = existingVulnerability
			}
		}

		// Insert/Update vulnerability
		if existingVulnerability == nil {
			// The vulnerability does not exist, create it

			// Verify parameters
			if vulnerability.ID == "" || vulnerability.Link == "" || vulnerability.Priority == "" {
				log.Warningf("could not insert an incomplete vulnerability [ID: %s, Link: %s, Priority: %s]", vulnerability.ID, vulnerability.Link, vulnerability.Priority)
				return []Notification{}, cerrors.NewBadRequestError("Could not insert an incomplete vulnerability")
			}
			if !vulnerability.Priority.IsValid() {
				log.Warningf("could not insert a vulnerability which has an invalid priority [ID: %s, Link: %s, Priority: %s]. Valid priorities are: %v.", vulnerability.ID, vulnerability.Link, vulnerability.Priority, types.Priorities)
				return []Notification{}, cerrors.NewBadRequestError("Could not insert a vulnerability which has an invalid priority")
			}
			if len(vulnerability.FixedInNodes) == 0 {
				log.Warningf("could not insert a vulnerability which doesn't affect any package [ID: %s].", vulnerability.ID)
				return []Notification{}, cerrors.NewBadRequestError("could not insert a vulnerability which doesn't affect any package")
			}

			// Insert it
			vulnerability.Node = vulnerability.GetNode()

			t.AddQuad(cayley.Quad(vulnerability.Node, fieldIs, fieldVulnerabilityIsValue, ""))
			t.AddQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityID, vulnerability.ID, ""))
			t.AddQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityLink, vulnerability.Link, ""))
			t.AddQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityPriority, string(vulnerability.Priority), ""))
			t.AddQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityDescription, vulnerability.Description, ""))
			for _, p := range vulnerability.FixedInNodes {
				t.AddQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityFixedIn, p, ""))
			}

			// Add a notification
			notification := &NewVulnerabilityNotification{VulnerabilityID: vulnerability.ID}
			notifications = append(notifications, notification)
			newVulnerabilityNotifications[vulnerability.ID] = notification

			cachedVulnerabilities[vulnerability.ID] = vulnerability
		} else {
			// The vulnerability already exists, update it
			if vulnerability.Link != "" && existingVulnerability.Link != vulnerability.Link {
				t.RemoveQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityLink, existingVulnerability.Link, ""))
				t.AddQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityLink, vulnerability.Link, ""))
				existingVulnerability.Link = vulnerability.Link
			}

			if vulnerability.Priority != "" && vulnerability.Priority != types.Unknown && existingVulnerability.Priority != vulnerability.Priority {
				if !vulnerability.Priority.IsValid() {
					log.Warningf("could not update a vulnerability which has an invalid priority [ID: %s, Link: %s, Priority: %s]. Valid priorities are: %v.", vulnerability.ID, vulnerability.Link, vulnerability.Priority, types.Priorities)
					return []Notification{}, cerrors.NewBadRequestError("Could not update a vulnerability which has an invalid priority")
				}

				// Add a notification about the priority change if the new priority is higher and the vulnerability is not new
				if vulnerability.Priority.Compare(existingVulnerability.Priority) > 0 {
					if _, newVulnerabilityNotificationExists := newVulnerabilityNotifications[vulnerability.ID]; !newVulnerabilityNotificationExists {
						// Any priorityChangeNotification already ?
						if existingPriorityNotification, _ := vulnerabilityPriorityIncreasedNotifications[vulnerability.ID]; existingPriorityNotification != nil {
							// There is a priority change notification, replace it but keep the old priority field
							existingPriorityNotification.NewPriority = vulnerability.Priority
						} else {
							// No previous notification, just add a new one
							notification := &VulnerabilityPriorityIncreasedNotification{OldPriority: existingVulnerability.Priority, NewPriority: vulnerability.Priority, VulnerabilityID: existingVulnerability.ID}
							notifications = append(notifications, notification)
							vulnerabilityPriorityIncreasedNotifications[vulnerability.ID] = notification
						}
					}
				}

				t.RemoveQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityPriority, string(existingVulnerability.Priority), ""))
				t.AddQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityPriority, string(vulnerability.Priority), ""))
				existingVulnerability.Priority = vulnerability.Priority
			}

			if vulnerability.Description != "" && existingVulnerability.Description != vulnerability.Description {
				t.RemoveQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityDescription, existingVulnerability.Description, ""))
				t.AddQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityDescription, vulnerability.Description, ""))
				existingVulnerability.Description = vulnerability.Description
			}

			newFixedInNodes := utils.CompareStringLists(vulnerability.FixedInNodes, existingVulnerability.FixedInNodes)
			if len(newFixedInNodes) > 0 {
				var removedNodes []string
				var addedNodes []string

				existingVulnerabilityFixedInPackages, err := FindAllPackagesByNodes(existingVulnerability.FixedInNodes, []string{FieldPackageOS, FieldPackageName, FieldPackageVersion})
				if err != nil {
					return []Notification{}, err
				}
				newFixedInPackages, err := FindAllPackagesByNodes(newFixedInNodes, []string{FieldPackageOS, FieldPackageName, FieldPackageVersion})
				if err != nil {
					return []Notification{}, err
				}

				for _, p := range newFixedInPackages {
					for _, ep := range existingVulnerabilityFixedInPackages {
						if p.Branch() == ep.Branch() {
							// A link to this package branch already exist and is not the same version, we will delete it
							t.RemoveQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityFixedIn, ep.Node, ""))

							var index int
							for i, n := range existingVulnerability.FixedInNodes {
								if n == ep.Node {
									index = i
									break
								}
							}
							existingVulnerability.FixedInNodes = append(existingVulnerability.FixedInNodes[index:], existingVulnerability.FixedInNodes[index+1:]...)
							removedNodes = append(removedNodes, ep.Node)
						}
					}

					t.AddQuad(cayley.Quad(existingVulnerability.Node, FieldVulnerabilityFixedIn, p.Node, ""))
					existingVulnerability.FixedInNodes = append(existingVulnerability.FixedInNodes, p.Node)
					addedNodes = append(addedNodes, p.Node)
				}

				// Add notification about the FixedIn modification if the vulnerability is not new
				if _, newVulnerabilityNotificationExists := newVulnerabilityNotifications[vulnerability.ID]; !newVulnerabilityNotificationExists {
					// Any VulnerabilityPackageChangedNotification already ?
					if existingPackageNotification, _ := vulnerabilityPackageChangedNotifications[vulnerability.ID]; existingPackageNotification != nil {
						// There is a priority change notification, add the packages modifications to it
						existingPackageNotification.AddedFixedInNodes = append(existingPackageNotification.AddedFixedInNodes, addedNodes...)
						existingPackageNotification.RemovedFixedInNodes = append(existingPackageNotification.RemovedFixedInNodes, removedNodes...)
					} else {
						// No previous notification, just add a new one
						notification := &VulnerabilityPackageChangedNotification{VulnerabilityID: vulnerability.ID, AddedFixedInNodes: addedNodes, RemovedFixedInNodes: removedNodes}
						notifications = append(notifications, notification)
						vulnerabilityPackageChangedNotifications[vulnerability.ID] = notification
					}
				}
			}
		}
	}

	// Apply transaction
	if err = store.ApplyTransaction(t); err != nil {
		log.Errorf("failed transaction (InsertVulnerabilities): %s", err)
		return []Notification{}, ErrTransaction
	}

	return notifications, nil
}

// DeleteVulnerability deletes the vulnerability having the given ID
func DeleteVulnerability(id string) error {
	vulnerability, err := FindOneVulnerability(id, FieldVulnerabilityAll)
	if err != nil {
		return err
	}

	t := cayley.NewTransaction()
	t.RemoveQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityID, vulnerability.ID, ""))
	t.RemoveQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityLink, vulnerability.Link, ""))
	t.RemoveQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityPriority, string(vulnerability.Priority), ""))
	t.RemoveQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityDescription, vulnerability.Description, ""))
	for _, p := range vulnerability.FixedInNodes {
		t.RemoveQuad(cayley.Quad(vulnerability.Node, FieldVulnerabilityFixedIn, p, ""))
	}

	if err := store.ApplyTransaction(t); err != nil {
		log.Errorf("failed transaction (DeleteVulnerability): %s", err)
		return ErrTransaction
	}

	return nil
}

// FindOneVulnerability finds and returns a single vulnerability having the given ID selecting the specified fields
func FindOneVulnerability(id string, selectedFields []string) (*Vulnerability, error) {
	t := &Vulnerability{ID: id}
	v, err := toVulnerabilities(cayley.StartPath(store, t.GetNode()).Has(fieldIs, fieldVulnerabilityIsValue), selectedFields)

	if err != nil {
		return nil, err
	}
	if len(v) == 1 {
		return v[0], nil
	}
	if len(v) > 1 {
		log.Errorf("found multiple vulnerabilities with identical ID [ID: %s]", id)
		return nil, ErrInconsistent
	}
	return nil, cerrors.ErrNotFound
}

// FindAllVulnerabilitiesByFixedIn finds and returns all vulnerabilities that are fixed in the given packages (speficied by their nodes), selecting the specified fields
func FindAllVulnerabilitiesByFixedIn(nodes []string, selectedFields []string) ([]*Vulnerability, error) {
	if len(nodes) == 0 {
		log.Warning("Could not FindAllVulnerabilitiesByFixedIn with an empty nodes array.")
		return []*Vulnerability{}, nil
	}

	// Construct path, potentially saving FieldVulnerabilityCausedByPackage
	path := cayley.StartPath(store, nodes...)
	if utils.Contains(FieldVulnerabilityCausedByPackage, selectedFields) {
		path = path.Save(FieldPackageName, FieldVulnerabilityCausedByPackage)
	}
	path = path.In(FieldVulnerabilityFixedIn)

	return toVulnerabilities(path, selectedFields)
}

// toVulnerabilities converts a path leading to one or multiple vulnerabilities to Vulnerability structs, selecting the specified fields
func toVulnerabilities(path *path.Path, selectedFields []string) ([]*Vulnerability, error) {
	var vulnerabilities []*Vulnerability

	saveFields(path, selectedFields, []string{FieldVulnerabilityFixedIn, FieldVulnerabilityCausedByPackage})
	it, _ := path.BuildIterator().Optimize()
	defer it.Close()
	for cayley.RawNext(it) {
		tags := make(map[string]graph.Value)
		it.TagResults(tags)

		vulnerability := Vulnerability{Node: store.NameOf(it.Result())}
		for _, selectedField := range selectedFields {
			switch selectedField {
			case FieldVulnerabilityID:
				vulnerability.ID = store.NameOf(tags[FieldVulnerabilityID])
			case FieldVulnerabilityLink:
				vulnerability.Link = store.NameOf(tags[FieldVulnerabilityLink])
			case FieldVulnerabilityPriority:
				vulnerability.Priority = types.Priority(store.NameOf(tags[FieldVulnerabilityPriority]))
			case FieldVulnerabilityDescription:
				vulnerability.Description = store.NameOf(tags[FieldVulnerabilityDescription])
			case FieldVulnerabilityFixedIn:
				var err error
				vulnerability.FixedInNodes, err = toValues(cayley.StartPath(store, vulnerability.Node).Out(FieldVulnerabilityFixedIn))
				if err != nil {
					log.Errorf("could not get fixedIn on vulnerability %s: %s.", vulnerability.Node, err.Error())
					return []*Vulnerability{}, err
				}
			case FieldVulnerabilityCausedByPackage:
				vulnerability.CausedByPackage = store.NameOf(tags[FieldVulnerabilityCausedByPackage])
			default:
				panic("unknown selectedField")
			}
		}
		vulnerabilities = append(vulnerabilities, &vulnerability)
	}
	if it.Err() != nil {
		log.Errorf("failed query in toVulnerabilities: %s", it.Err())
		return []*Vulnerability{}, ErrBackendException
	}

	return vulnerabilities, nil
}