api/models/change.go

package models

import (
	"fmt"
	"reflect"
	"strings"
	"time"
)

// Change represents a change in the rpdata history through the API.
type Change struct {
	ID     string      `bson:"_id"`
	Model  ChangeModel `bson:"model"`
	Op     string      `bson:"op"`
	Author string      `bson:"author"`
	Listed bool        `bson:"listed"`
	Keys   []ChangeKey `bson:"keys"`
	Date   time.Time   `bson:"date"`

	ChangeObjectSet
}

type ChangeObjectSet struct {
	Logs       []*Log       `bson:"logs" json:"logs,omitempty"`
	Characters []*Character `bson:"characters" json:"characters,omitempty"`
	Channels   []*Channel   `bson:"channels" json:"channels,omitempty"`
	Posts      []*Post      `bson:"posts" json:"posts,omitempty"`
	Stories    []*Story     `bson:"stories" json:"stories,omitempty"`
	Tags       []*Tag       `bson:"tags" json:"tags,omitempty"`
	Chapters   []*Chapter   `bson:"chapters" json:"chapters,omitempty"`
	Comments   []*Comment   `bson:"comments" json:"comments,omitempty"`
	Files      []*File      `bson:"files" json:"files,omitempty"`
}

// AddObject adds the model into the appropriate array.
func (change *ChangeObjectSet) AddObject(object interface{}) bool {
	if v := reflect.ValueOf(object); v.Kind() == reflect.Struct {
		ptr := reflect.PtrTo(v.Type())
		ptrValue := reflect.New(ptr.Elem())
		ptrValue.Elem().Set(v)

		object = ptrValue.Interface()
	}

	switch object := object.(type) {
	case *Log:
		change.Logs = append(change.Logs, object)
	case []*Log:
		change.Logs = append(change.Logs, object...)
	case *Character:
		change.Characters = append(change.Characters, object)
	case []*Character:
		change.Characters = append(change.Characters, object...)
	case *Channel:
		change.Channels = append(change.Channels, object)
	case []*Channel:
		change.Channels = append(change.Channels, object...)
	case *Post:
		change.Posts = append(change.Posts, object)
	case []*Post:
		change.Posts = append(change.Posts, object...)
	case *Story:
		change.Stories = append(change.Stories, object)
	case []*Story:
		change.Stories = append(change.Stories, object...)
	case *Tag:
		change.Tags = append(change.Tags, object)
	case []*Tag:
		change.Tags = append(change.Tags, object...)
	case *Chapter:
		change.Chapters = append(change.Chapters, object)
	case []*Chapter:
		change.Chapters = append(change.Chapters, object...)
	case *Comment:
		change.Comments = append(change.Comments, object)
	case []*Comment:
		change.Comments = append(change.Comments, object...)
	case *File:
		change.Files = append(change.Files, object)
	case []*File:
		change.Files = append(change.Files, object...)
	default:
		return false
	}

	return true
}

// Objects makes a combined, mixed array of all the models stored in this change.
func (change *Change) Objects() []interface{} {
	data := make([]interface{}, 0, 8)

	for _, log := range change.Logs {
		data = append(data, log)
	}
	for _, channel := range change.Channels {
		data = append(data, channel)
	}
	for _, character := range change.Characters {
		data = append(data, character)
	}
	for _, post := range change.Posts {
		data = append(data, post)
	}
	for _, story := range change.Stories {
		data = append(data, story)
	}
	for _, tag := range change.Tags {
		data = append(data, tag)
	}
	for _, chapter := range change.Chapters {
		data = append(data, chapter)
	}
	for _, comment := range change.Comments {
		data = append(data, comment)
	}
	for _, file := range change.Files {
		data = append(data, file)
	}

	return data
}

func (change *Change) PassesFilter(filter ChangeFilter) bool {
	if filter.Author != nil && change.Author != *filter.Author {
		return false
	}

	// For unlisted changes, pass it only if the filter refers to the specific index.
	if !change.Listed {
		hasSpecificKey := false

	KeyFindLoop:
		for _, key := range filter.Keys {
			if key.ID == "*" {
				continue
			}

			for _, changeKey := range change.Keys {
				if changeKey.Model == key.Model && changeKey.ID == key.ID {
					hasSpecificKey = true
					break KeyFindLoop
				}
			}
		}

		if !hasSpecificKey {
			return false
		}
	}

	if filter.EarliestDate != nil && filter.EarliestDate.Before(change.Date) {
		return false
	}

	if len(filter.Keys) > 0 {
		foundKey := false

	KeyFindLoop2:
		for _, key := range filter.Keys {
			for _, changeKey := range change.Keys {
				if changeKey == key {
					foundKey = true
					break KeyFindLoop2
				}
			}
		}

		if !foundKey {
			return false
		}
	}

	return true
}

// ChangeKey is a key for a change that can be used when subscribing to them.
type ChangeKey struct {
	Model ChangeModel `bson:"model"`
	ID    string      `bson:"id"`
}

func (ck *ChangeKey) String() string {
	return ck.Model.String() + ":" + ck.ID
}

func (ck *ChangeKey) Decode(str string) error {
	split := strings.Split(str, ":")
	if len(split) != 2 {
		return fmt.Errorf("invalid change key: %s", str)
	}

	model := ChangeModel(split[0])
	if !model.IsValid() {
		return fmt.Errorf("invalid change key model: %s", model)
	}

	ck.Model = model
	ck.ID = split[1]

	return nil
}

// ChangeFilter is a filter for listing changes.
type ChangeFilter struct {
	Keys         []ChangeKey
	EarliestDate *time.Time
	LatestDate   *time.Time
	Author       *string
	Limit        *int
}