package toc

import (
	"math"
	"testing"

	"github.com/mk6i/open-oscar-server/wire"
	"github.com/stretchr/testify/assert"
)

func TestFeedbagList_upsertItem(t *testing.T) {
	t.Run("generates unique ItemID", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 42 })

		result, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "alice",
			ClassID: wire.FeedbagClassIdBuddy,
			GroupID: 1,
		})
		assert.True(t, inserted)
		assert.Equal(t, uint16(42), result.ItemID)
		assert.Equal(t, "alice", result.Name)
		assert.Equal(t, wire.FeedbagClassIdBuddy, result.ClassID)
		assert.Equal(t, uint16(1), result.GroupID)
	})

	t.Run("subsequent insert avoids collision", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 42 })

		fl.upsertItem(wire.FeedbagItem{
			Name:    "alice",
			ClassID: wire.FeedbagClassIdBuddy,
			GroupID: 1,
		})
		result, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "bob",
			ClassID: wire.FeedbagClassIdBuddy,
			GroupID: 1,
		})
		assert.True(t, inserted)
		assert.Equal(t, uint16(43), result.ItemID)
	})

	t.Run("non-buddy item does not update group order", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 5 })
		fl.upsertItem(wire.FeedbagItem{
			Name:    "alice",
			ClassID: wire.FeedbagClassIDPermit,
		})
		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 1)
		assert.Equal(t, wire.FeedbagClassIDPermit, upserts[0].ClassID)
	})

	t.Run("updates existing non-buddy item in place", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{
				Name:    "alice",
				ClassID: wire.FeedbagClassIDPermit,
				ItemID:  7,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(0x01, uint16(100)),
					},
				},
			},
		}, nil)

		_, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "alice",
			ClassID: wire.FeedbagClassIDPermit,
			TLVLBlock: wire.TLVLBlock{
				TLVList: wire.TLVList{
					wire.NewTLVBE(0x01, uint16(200)),
				},
			},
		})
		assert.False(t, inserted)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 1)
		assert.Equal(t, uint16(7), upserts[0].ItemID)
		val, ok := upserts[0].Uint16BE(0x01)
		assert.True(t, ok)
		assert.Equal(t, uint16(200), val)
	})

	t.Run("updates existing buddy item matched by group", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Group1", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
			{Name: "Group2", ClassID: wire.FeedbagClassIdGroup, GroupID: 2},
			{Name: "alice", ClassID: wire.FeedbagClassIdBuddy, GroupID: 1, ItemID: 10},
			{Name: "alice", ClassID: wire.FeedbagClassIdBuddy, GroupID: 2, ItemID: 20},
		}, nil)

		_, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "alice",
			ClassID: wire.FeedbagClassIdBuddy,
			GroupID: 2,
			TLVLBlock: wire.TLVLBlock{
				TLVList: wire.TLVList{
					wire.NewTLVBE(0x01, uint16(999)),
				},
			},
		})
		assert.False(t, inserted)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 1)
		assert.Equal(t, uint16(2), upserts[0].GroupID)
		assert.Equal(t, "alice", upserts[0].Name)
		assert.Equal(t, uint16(20), upserts[0].ItemID)
		val, ok := upserts[0].Uint16BE(0x01)
		assert.True(t, ok)
		assert.Equal(t, uint16(999), val)
	})

	t.Run("skips update when existing item is identical", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{
				Name:    "alice",
				ClassID: wire.FeedbagClassIDPermit,
				ItemID:  7,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(0x01, uint16(100)),
					},
				},
			},
		}, nil)

		_, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "alice",
			ClassID: wire.FeedbagClassIDPermit,
			ItemID:  7,
			TLVLBlock: wire.TLVLBlock{
				TLVList: wire.TLVList{
					wire.NewTLVBE(0x01, uint16(100)),
				},
			},
		})
		assert.False(t, inserted)

		assert.Nil(t, fl.PendingUpdates())
	})

	t.Run("normalized screen name: buddy stored with lowercase name", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 10 })

		result, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "Alice",
			ClassID: wire.FeedbagClassIdBuddy,
			GroupID: 1,
		})
		assert.True(t, inserted)
		assert.Equal(t, "alice", result.Name)
	})

	t.Run("normalized screen name: buddy upsert with different case matches existing", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
			{Name: "alice", ClassID: wire.FeedbagClassIdBuddy, GroupID: 1, ItemID: 99},
		}, nil)

		result, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "ALICE",
			ClassID: wire.FeedbagClassIdBuddy,
			GroupID: 1,
		})
		assert.False(t, inserted)
		assert.Equal(t, uint16(99), result.ItemID)
		assert.Equal(t, "alice", result.Name)
	})

	t.Run("normalized screen name: permit stored with lowercase name and spaces stripped", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 1 })

		result, _ := fl.upsertItem(wire.FeedbagItem{
			Name:    " Bob Smith ",
			ClassID: wire.FeedbagClassIDPermit,
		})
		assert.Equal(t, "bobsmith", result.Name)
	})

	t.Run("normalized screen name: permit upsert with different case matches existing", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "bob", ClassID: wire.FeedbagClassIDPermit, ItemID: 5},
		}, nil)

		result, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "BOB",
			ClassID: wire.FeedbagClassIDPermit,
		})
		assert.False(t, inserted)
		assert.Equal(t, "bob", result.Name)
		assert.Equal(t, uint16(5), result.ItemID)
	})

	t.Run("normalized screen name: deny upsert with different case matches existing", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "charlie", ClassID: wire.FeedbagClassIDDeny, ItemID: 3},
		}, nil)

		result, inserted := fl.upsertItem(wire.FeedbagItem{
			Name:    "Charlie",
			ClassID: wire.FeedbagClassIDDeny,
		})
		assert.False(t, inserted)
		assert.Equal(t, "charlie", result.Name)
		assert.Equal(t, uint16(3), result.ItemID)
	})
}

func TestFeedbagList_deleteItem(t *testing.T) {
	t.Run("non-buddy item does not update group order", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "alice", ClassID: wire.FeedbagClassIDPermit, ItemID: 5},
		}, nil)

		fl.deleteItem(wire.FeedbagItem{Name: "alice", ClassID: wire.FeedbagClassIDPermit, ItemID: 5})

		deletes := fl.PendingDeletes()
		assert.Len(t, deletes, 1)
		assert.Nil(t, fl.PendingUpdates())
	})

	t.Run("removes item from items list", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "alice", ClassID: wire.FeedbagClassIDPermit, ItemID: 1},
			{Name: "bob", ClassID: wire.FeedbagClassIDPermit, ItemID: 2},
			{Name: "charlie", ClassID: wire.FeedbagClassIDPermit, ItemID: 3},
		}, nil)

		fl.deleteItem(wire.FeedbagItem{Name: "bob", ClassID: wire.FeedbagClassIDPermit, ItemID: 2})

		deletes := fl.PendingDeletes()
		assert.Len(t, deletes, 1)
		assert.Equal(t, "bob", deletes[0].Name)
		assert.Equal(t, wire.FeedbagClassIDPermit, deletes[0].ClassID)
	})

	t.Run("multiple deletes accumulate", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "alice", ClassID: wire.FeedbagClassIDDeny, ItemID: 1},
			{Name: "bob", ClassID: wire.FeedbagClassIDDeny, ItemID: 2},
		}, nil)

		fl.deleteItem(wire.FeedbagItem{Name: "alice", ClassID: wire.FeedbagClassIDDeny, ItemID: 1})
		fl.deleteItem(wire.FeedbagItem{Name: "bob", ClassID: wire.FeedbagClassIDDeny, ItemID: 2})

		deletes := fl.PendingDeletes()
		assert.Len(t, deletes, 2)
	})

	t.Run("normalized screen name: delete buddy by different case", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
			{Name: "alice", ClassID: wire.FeedbagClassIdBuddy, GroupID: 1, ItemID: 50},
		}, nil)

		deleted, found := fl.deleteItem(wire.FeedbagItem{
			Name:    "ALICE",
			ClassID: wire.FeedbagClassIdBuddy,
			GroupID: 1,
		})
		assert.True(t, found)
		assert.Equal(t, "alice", deleted.Name)
		assert.Equal(t, uint16(50), deleted.ItemID)
	})

	t.Run("normalized screen name: delete permit by different case", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "bob", ClassID: wire.FeedbagClassIDPermit, ItemID: 7},
		}, nil)

		deleted, found := fl.deleteItem(wire.FeedbagItem{Name: "Bob", ClassID: wire.FeedbagClassIDPermit})
		assert.True(t, found)
		assert.Equal(t, "bob", deleted.Name)
	})

	t.Run("normalized screen name: delete deny by different case", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "charlie", ClassID: wire.FeedbagClassIDDeny, ItemID: 8},
		}, nil)

		deleted, found := fl.deleteItem(wire.FeedbagItem{Name: "CHARLIE", ClassID: wire.FeedbagClassIDDeny})
		assert.True(t, found)
		assert.Equal(t, "charlie", deleted.Name)
	})
}

func TestFeedbagList_genID(t *testing.T) {
	tt := []struct {
		name    string
		randInt func(n int) int
		items   []wire.FeedbagItem
		want    uint16
	}{
		{
			name:    "empty items list returns random ID",
			randInt: func(n int) int { return 1000 },
			items:   []wire.FeedbagItem{},
			want:    1000,
		},
		{
			name:    "finds next available ID when starting ID conflicts with ItemID",
			randInt: func(n int) int { return 100 },
			items: []wire.FeedbagItem{
				{ItemID: 100, GroupID: 1},
				{ItemID: 101, GroupID: 1},
			},
			want: 102,
		},
		{
			name:    "finds next available ID when starting ID conflicts with GroupID",
			randInt: func(n int) int { return 50 },
			items: []wire.FeedbagItem{
				{ItemID: 1, GroupID: 50},
				{ItemID: 2, GroupID: 51},
			},
			want: 52,
		},
		{
			name:    "wraps around and skips 0 to find next available ID",
			randInt: func(n int) int { return math.MaxUint16 - 2 },
			items: []wire.FeedbagItem{
				{ItemID: math.MaxUint16 - 2, GroupID: 1},
				{ItemID: math.MaxUint16 - 1, GroupID: 1},
				{ItemID: math.MaxUint16, GroupID: 1},
			},
			want: 2,
		},
		{
			name:    "skips 0 when starting from 0 and finds next available",
			randInt: func(n int) int { return 0 },
			items:   []wire.FeedbagItem{},
			want:    1,
		},
		{
			name:    "returns 0 when all IDs are taken",
			randInt: func(n int) int { return 100 },
			items: func() []wire.FeedbagItem {
				items := make([]wire.FeedbagItem, 0, math.MaxUint16+1)
				for i := 0; i <= math.MaxUint16; i++ {
					items = append(items, wire.FeedbagItem{
						ItemID:  uint16(i),
						GroupID: uint16(i),
					})
				}
				return items
			}(),
			want: 0,
		},
		{
			name:    "finds ID that conflicts with both ItemID and GroupID",
			randInt: func(n int) int { return 200 },
			items: []wire.FeedbagItem{
				{ItemID: 200, GroupID: 201},
				{ItemID: 201, GroupID: 200},
			},
			want: 202,
		},
		{
			name:    "finds available ID immediately when no conflicts",
			randInt: func(n int) int { return 500 },
			items: []wire.FeedbagItem{
				{ItemID: 100, GroupID: 1},
				{ItemID: 200, GroupID: 2},
				{ItemID: 300, GroupID: 3},
			},
			want: 500,
		},
		{
			name:    "handles single conflict and finds next",
			randInt: func(n int) int { return 42 },
			items: []wire.FeedbagItem{
				{ItemID: 42, GroupID: 1},
			},
			want: 43,
		},
		{
			name:    "finds ID before starting point when wrapping",
			randInt: func(n int) int { return 5 },
			items: []wire.FeedbagItem{
				{ItemID: 5, GroupID: 1},
				{ItemID: 6, GroupID: 1},
				{ItemID: 7, GroupID: 1},
			},
			want: 8,
		},
	}

	for _, tc := range tt {
		t.Run(tc.name, func(t *testing.T) {
			fl := newFeedbagList(tc.items, tc.randInt)
			got := fl.genID()
			assert.Equal(t, tc.want, got)
		})
	}
}

func TestFeedbagList_AddGroup(t *testing.T) {
	t.Run("creates group and root group when none exists", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 5 })

		group := fl.AddGroup("Buddies")

		assert.Equal(t, uint16(5), group.GroupID)
		assert.Equal(t, "Buddies", group.Name)
		assert.Equal(t, wire.FeedbagClassIdGroup, group.ClassID)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 2)
		root := upserts[0]
		assert.Equal(t, wire.FeedbagClassIdGroup, root.ClassID)
		assert.Equal(t, uint16(0), root.GroupID)
		order, ok := root.Uint16SliceBE(wire.FeedbagAttributesOrder)
		assert.True(t, ok)
		assert.Equal(t, []uint16{5}, order)
	})

	t.Run("updates existing root group order", func(t *testing.T) {
		existing := []wire.FeedbagItem{
			{
				ClassID: wire.FeedbagClassIdGroup,
				GroupID: 0,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(wire.FeedbagAttributesOrder, []uint16{1}),
					},
				},
			},
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}
		callCount := 0
		fl := newFeedbagList(existing, func(n int) int {
			callCount++
			return callCount + 1
		})

		group := fl.AddGroup("Coworkers")

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 2)
		order, ok := upserts[0].Uint16SliceBE(wire.FeedbagAttributesOrder)
		assert.True(t, ok)
		assert.Equal(t, []uint16{1, group.GroupID}, order)
	})

	t.Run("multiple AddGroup calls accumulate in root order", func(t *testing.T) {
		callCount := 0
		fl := newFeedbagList(nil, func(n int) int {
			callCount++
			return callCount * 10
		})

		g1 := fl.AddGroup("Group1")
		g2 := fl.AddGroup("Group2")

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 3)
		order, ok := upserts[0].Uint16SliceBE(wire.FeedbagAttributesOrder)
		assert.True(t, ok)
		assert.Equal(t, []uint16{g1.GroupID, g2.GroupID}, order)
	})
}

func TestFeedbagList_DeleteGroup(t *testing.T) {
	t.Run("updates root group order", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{
				Name:    "",
				ClassID: wire.FeedbagClassIdGroup,
				GroupID: 0,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(wire.FeedbagAttributesOrder, []uint16{1, 2, 3}),
					},
				},
			},
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
			{Name: "Coworkers", ClassID: wire.FeedbagClassIdGroup, GroupID: 2},
			{Name: "Family", ClassID: wire.FeedbagClassIdGroup, GroupID: 3},
		}, nil)

		fl.DeleteGroup("Coworkers")

		deletes := fl.PendingDeletes()
		assert.Len(t, deletes, 1)
		assert.Equal(t, "Coworkers", deletes[0].Name)
		assert.Equal(t, uint16(2), deletes[0].GroupID)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 1)
		assert.Equal(t, uint16(0), upserts[0].GroupID)
		order, ok := upserts[0].Uint16SliceBE(wire.FeedbagAttributesOrder)
		assert.True(t, ok)
		assert.Equal(t, []uint16{1, 3}, order)
	})
}

func TestFeedbagList_AddBuddy(t *testing.T) {
	t.Run("updates parent group order", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 50 })

		inserted, err := fl.AddBuddy("Buddies", "alice", "", "")
		assert.NoError(t, err)
		assert.True(t, inserted)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 2)
		assert.Equal(t, uint16(1), upserts[1].GroupID)
		order, ok := upserts[1].Uint16SliceBE(wire.FeedbagAttributesOrder)
		assert.True(t, ok)
		assert.Equal(t, []uint16{upserts[0].ItemID}, order)
	})

	t.Run("multiple buddies accumulate in parent group order", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{
				Name:    "Buddies",
				ClassID: wire.FeedbagClassIdGroup,
				GroupID: 1,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(wire.FeedbagAttributesOrder, []uint16{10}),
					},
				},
			},
		}, func(n int) int { return 50 })

		_, err := fl.AddBuddy("Buddies", "alice", "", "")
		assert.NoError(t, err)
		_, err = fl.AddBuddy("Buddies", "bob", "", "")
		assert.NoError(t, err)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 3)
		order, ok := upserts[1].Uint16SliceBE(wire.FeedbagAttributesOrder)
		assert.True(t, ok)
		assert.Equal(t, []uint16{10, upserts[0].ItemID, upserts[2].ItemID}, order)
	})

	t.Run("returns error when parent group does not exist", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 5 })
		_, err := fl.AddBuddy("Nonexistent", "alice", "", "")
		assert.ErrorContains(t, err, "group \"Nonexistent\" not found")
	})

	t.Run("normalized screen name: stores buddy with lowercase name", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 1 })

		inserted, err := fl.AddBuddy("Buddies", "Alice", "", "")
		assert.NoError(t, err)
		assert.True(t, inserted)

		upserts := fl.PendingUpdates()
		var buddy *wire.FeedbagItem
		for i := range upserts {
			if upserts[i].ClassID == wire.FeedbagClassIdBuddy {
				buddy = &upserts[i]
				break
			}
		}
		assert.NotNil(t, buddy)
		assert.Equal(t, "alice", buddy.Name)
	})

	t.Run("normalized screen name: second AddBuddy with different case does not insert duplicate", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 1 })

		inserted1, err := fl.AddBuddy("Buddies", "alice", "", "")
		assert.NoError(t, err)
		assert.True(t, inserted1)

		inserted2, err := fl.AddBuddy("Buddies", "ALICE", "", "")
		assert.NoError(t, err)
		assert.False(t, inserted2)
	})

	t.Run("normalized screen name: DeleteBuddy finds buddy by different case", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 1 })
		_, err := fl.AddBuddy("Buddies", "alice", "", "")
		assert.NoError(t, err)
		_ = fl.PendingUpdates()

		err = fl.DeleteBuddy("Buddies", "Alice")
		assert.NoError(t, err)
		deletes := fl.PendingDeletes()
		assert.Len(t, deletes, 1)
		assert.Equal(t, "alice", deletes[0].Name)
	})
}

func TestFeedbagList_DeleteBuddy(t *testing.T) {
	t.Run("updates parent group order", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{
				Name:    "Buddies",
				ClassID: wire.FeedbagClassIdGroup,
				GroupID: 1,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(wire.FeedbagAttributesOrder, []uint16{10, 20, 30}),
					},
				},
			},
			{Name: "alice", ClassID: wire.FeedbagClassIdBuddy, GroupID: 1, ItemID: 10},
			{Name: "bob", ClassID: wire.FeedbagClassIdBuddy, GroupID: 1, ItemID: 20},
			{Name: "charlie", ClassID: wire.FeedbagClassIdBuddy, GroupID: 1, ItemID: 30},
		}, nil)

		err := fl.DeleteBuddy("Buddies", "bob")
		assert.NoError(t, err)

		deletes := fl.PendingDeletes()
		assert.Len(t, deletes, 1)
		assert.Equal(t, "bob", deletes[0].Name)
		assert.Equal(t, uint16(20), deletes[0].ItemID)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 1)
		order, ok := upserts[0].Uint16SliceBE(wire.FeedbagAttributesOrder)
		assert.True(t, ok)
		assert.Equal(t, []uint16{10, 30}, order)
	})

	t.Run("removes only buddy in specified group when same screen name in two groups", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{
				Name:    "Buddies",
				ClassID: wire.FeedbagClassIdGroup,
				GroupID: 1,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(wire.FeedbagAttributesOrder, []uint16{10, 20}),
					},
				},
			},
			{
				Name:    "Coworkers",
				ClassID: wire.FeedbagClassIdGroup,
				GroupID: 2,
				TLVLBlock: wire.TLVLBlock{
					TLVList: wire.TLVList{
						wire.NewTLVBE(wire.FeedbagAttributesOrder, []uint16{20}),
					},
				},
			},
			{Name: "alice", ClassID: wire.FeedbagClassIdBuddy, GroupID: 2, ItemID: 20},
			{Name: "alice", ClassID: wire.FeedbagClassIdBuddy, GroupID: 1, ItemID: 10},
		}, nil)

		err := fl.DeleteBuddy("Buddies", "alice")
		assert.NoError(t, err)

		deletes := fl.PendingDeletes()
		assert.Len(t, deletes, 1)
		assert.Equal(t, "alice", deletes[0].Name)
		assert.Equal(t, uint16(1), deletes[0].GroupID, "should delete from Buddies (group 1), not Coworkers (group 2)")
		assert.Equal(t, uint16(10), deletes[0].ItemID)
	})
}

func TestFeedbagList_PendingUpdates(t *testing.T) {
	t.Run("empty when nothing inserted", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 1 })
		assert.Nil(t, fl.PendingUpdates())
	})
	t.Run("includes inserts and updates", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "Buddies", ClassID: wire.FeedbagClassIdGroup, GroupID: 1},
		}, func(n int) int { return 50 })
		_, err := fl.AddBuddy("Buddies", "alice", "", "")
		assert.NoError(t, err)
		_, err = fl.AddBuddy("Buddies", "bob", "", "")
		assert.NoError(t, err)
		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 3)
		assert.Equal(t, wire.FeedbagClassIdBuddy, upserts[0].ClassID)
		assert.Equal(t, wire.FeedbagClassIdGroup, upserts[1].ClassID)
		assert.Equal(t, wire.FeedbagClassIdBuddy, upserts[2].ClassID)
	})
	t.Run("clears after retrieval", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 5 })
		fl.AddGroup("Buddies")
		assert.Len(t, fl.PendingUpdates(), 2)
		assert.Nil(t, fl.PendingUpdates())
	})
}

func TestFeedbagList_PendingDeletes(t *testing.T) {
	t.Run("empty when nothing deleted", func(t *testing.T) {
		fl := newFeedbagList(nil, nil)
		assert.Nil(t, fl.PendingDeletes())
	})

	t.Run("clears after retrieval", func(t *testing.T) {
		fl := newFeedbagList([]wire.FeedbagItem{
			{Name: "alice", ClassID: wire.FeedbagClassIDPermit, ItemID: 1},
		}, nil)
		fl.deleteItem(wire.FeedbagItem{Name: "alice", ClassID: wire.FeedbagClassIDPermit, ItemID: 1})
		assert.Len(t, fl.PendingDeletes(), 1)
		assert.Nil(t, fl.PendingDeletes())
	})
}

func TestFeedbagList_PendingUpdates_upsertsOnly(t *testing.T) {
	t.Run("tracks upserted items", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 5 })
		result, inserted := fl.upsertItem(wire.FeedbagItem{ClassID: wire.FeedbagClassIDPermit, Name: "alice"})
		assert.True(t, inserted)

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 1)
		assert.Equal(t, "alice", upserts[0].Name)
		assert.Equal(t, uint16(5), result.ItemID)
	})

	t.Run("clears after retrieval", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 5 })
		fl.upsertItem(wire.FeedbagItem{ClassID: wire.FeedbagClassIDPermit})
		assert.Len(t, fl.PendingUpdates(), 1)
		assert.Nil(t, fl.PendingUpdates())
	})

	t.Run("multiple inserts accumulate", func(t *testing.T) {
		fl := newFeedbagList(nil, func(n int) int { return 10 })
		fl.upsertItem(wire.FeedbagItem{ClassID: wire.FeedbagClassIDPermit, Name: "alice"})
		fl.upsertItem(wire.FeedbagItem{ClassID: wire.FeedbagClassIDPermit, Name: "bob"})

		upserts := fl.PendingUpdates()
		assert.Len(t, upserts, 2)
	})
}