describe "Monarch.Relations.Offset", ->
  BlogPost = null

  beforeEach ->
    class BlogPost extends Monarch.Record
      @extended(this)
      @columns title: "string"
      @defaultOrderBy('title')

  describe "#all()", ->
    it "returns the records from the operand with the first 'count' discarded", ->
      post1 = BlogPost.created(id: 1, title: "Alpha")
      post2 = BlogPost.created(id: 2, title: "Bravo")
      post3 = BlogPost.created(id: 3, title: "Charlie")
      post4 = BlogPost.created(id: 4, title: "Delta")

      expect(BlogPost.offset(2).all()).toEqual([post3, post4])

  describe "events", ->
    [subscriptions, insertCallback, updateCallback, removeCallback] = []
    [post1, post2, post3] = []

    beforeEach ->
      subscriptions = new Monarch.Util.SubscriptionBundle()
      insertCallback = jasmine.createSpy('insertCallback')
      updateCallback = jasmine.createSpy('updateCallback')
      removeCallback = jasmine.createSpy('removeCallback')

      relation = BlogPost.offset(2)
      subscriptions.add(relation.onInsert(insertCallback))
      subscriptions.add(relation.onUpdate(updateCallback))
      subscriptions.add(relation.onRemove(removeCallback))

      post1 = BlogPost.created(id: 1, title: "Alpha")
      post2 = BlogPost.created(id: 2, title: "Charlie")
      expect(insertCallback).not.toHaveBeenCalled()
      post3 = BlogPost.created(id: 3, title: "Echo")
      insertCallback.reset()

    describe "insert events", ->
      it "triggers an insert event when a record is inserted in the operand with an index >= count", ->
        post4 = BlogPost.created(id: 4, title: "Golf")
        expect(insertCallback).toHaveBeenCalled()
        expect(insertCallback.arg(0)).toBe(post4)
        expect(insertCallback.arg(1)).toBe(1)

      it "triggers an insert event for the new first record when a record is inserted with an index < count and there are enough records to exceed the offset", ->
        BlogPost.created(id: 4, title: "Bravo")
        expect(insertCallback).toHaveBeenCalled()
        expect(insertCallback.arg(0)).toBe(post2)
        expect(insertCallback.arg(1)).toBe(0)

      it "triggers an insert event when an operand record is updated from an index less than count to an index >= count", ->
        post1.updated(title: "Uniform")
        expect(insertCallback).toHaveBeenCalled()
        expect(insertCallback.arg(0)).toBe(post1)
        expect(insertCallback.arg(1)).toBe(0)

      it "triggers an insert event for the new first record when a record is updated to be less than count and pushes it into place", ->
        post3.updated(title: "Bravo")
        expect(insertCallback).toHaveBeenCalled()
        expect(insertCallback.arg(0)).toBe(post2)
        expect(insertCallback.arg(1)).toBe(0)

    describe "update events", ->
      it "triggers an update event when a tuple is updated from an index >= count to and index >= count", ->
        post3.updated(title: "Zulu")
        expect(updateCallback).toHaveBeenCalled()
        expect(updateCallback.arg(0)).toBe(post3)
        expect(updateCallback.arg(1)).toEqual
          title:
            oldValue: "Echo"
            newValue: "Zulu"
            column: BlogPost.getColumn('title')
        expect(updateCallback.arg(2)).toBe(0)
        expect(updateCallback.arg(3)).toBe(0)
        updateCallback.reset()

        post1.updated(title: "Bravo")
        expect(updateCallback).not.toHaveBeenCalled()

    describe "remove events", ->
      it "triggers a remove event when a tuple is removed with an index >= count", ->
        post3.destroyed()
        expect(removeCallback).toHaveBeenCalled()
        expect(removeCallback.arg(0)).toBe(post3)
        expect(removeCallback.arg(1)).toBe(0)

      it "triggers a remove event when a tuple is updated in the operand from an index >= count to an index < count", ->
        post3.updated(title: "Bravo")
        expect(removeCallback).toHaveBeenCalled()
        expect(removeCallback.arg(0)).toBe(post3)
        expect(removeCallback.arg(1)).toBe(0)

      it "triggers a remove event for the first tuple when a tuple is removed from the operand with an index < count", ->
        post1.destroyed()
        expect(removeCallback).toHaveBeenCalled()
        expect(removeCallback.arg(0)).toBe(post3)
        expect(removeCallback.arg(1)).toBe(0)

      it "triggers a remove event for the first tuple when a tuple is updated in the operand from an index < count to an index >= count", ->
        post1.updated(title: "Zulu")
        expect(removeCallback).toHaveBeenCalled()
        expect(removeCallback.arg(0)).toBe(post3)
        expect(removeCallback.arg(1)).toBe(0)

  it "has a #wireRepresentation()", ->
    expect(BlogPost.offset(5).wireRepresentation()).toEqual
      type: 'Offset'
      operand: BlogPost.table.wireRepresentation()
      count: 5