1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10
11. 11
12. 12
13. 13
14. 14
15. 15
16. 16
17. 17
18. 18
19. 19
20. 20
21. 21
22. 22
23. 23
24. 24
25. 25
26. 26
27. 27
28. 28
29. 29
30. 30
31. 31
32. 32
33. 33
34. 34
35. 35
36. 36
37. 37
38. 38
39. 39
40. 40
41. 41
42. 42
43. 43
44. 44
45. 45
46. 46
47. 47
48. 48
49. 49
50. 50
51. 51
52. 52
53. 53
54. 54
55. 55
56. 56
57. 57
58. 58
59. 59
60. 60
61. 61
62. 62
63. 63
64. 64
65. 65
66. 66
67. 67
68. 68
69. 69
70. 70
71. 71
72. 72
73. 73
74. 74
75. 75
76. 76
77. 77
78. 78
79. 79
80. 80
81. 81
82. 82
83. 83
84. 84
85. 85
86. 86
87. 87
88. 88
89. 89
90. 90
91. 91
92. 92
93. 93
94. 94
95. 95
96. 96
97. 97
98. 98
99. 99
100. 100
101. 101
102. 102
103. 103
104. 104
105. 105

// SPDX-FileCopyrightText: 2025 Shota FUJI <pockawoooh@gmail.com>
// SPDX-License-Identifier: AGPL-3.0-only

package event

import (
	"database/sql"
	"slices"

	"google.golang.org/protobuf/proto"

	eventsV1 "pocka.jp/x/yamori/proto/go/backend/events/v1"
)

type Event struct {
	Seq     uint64
	Payload *eventsV1.Event
}

func AppendEvents(tx *sql.Tx, events []*eventsV1.Event) error {
	stmt, err := tx.Prepare("INSERT INTO events (payload) VALUES (?)")
	if err != nil {
		return nil
	}

	for _, event := range events {
		b, err := proto.Marshal(event)
		if err != nil {
			return err
		}

		if _, err = stmt.Exec(b); err != nil {
			return err
		}
	}

	return nil
}

func listEvents(tx *sql.Tx, startSeq uint64) ([]Event, error) {
	rows, err := tx.Query("SELECT seq, payload FROM events WHERE seq >= ? ORDER BY seq ASC", startSeq)
	if err != nil {
		return nil, err
	}

	ret := make([]Event, 0)
	for rows.Next() {
		var seq uint64
		var payload []byte
		if err := rows.Scan(&seq, &payload); err != nil {
			return nil, err
		}

		var event eventsV1.Event
		if err := proto.Unmarshal(payload, &event); err != nil {
			return nil, err
		}

		ret = append(ret, Event{
			Seq:     seq,
			Payload: &event,
		})
	}

	return ret, nil
}

type Projection interface {
	EventSeq() *uint64

	Update(events []Event)

	SaveSnapshot(tx *sql.Tx) error
}

func UpdateProjections(tx *sql.Tx, projections ...Projection) error {
	seqs := make([]uint64, 0, len(projections))
	for _, p := range projections {
		seq := p.EventSeq()
		if seq == nil {
			continue
		}

		seqs = append(seqs, *seq)
	}

	startSeq := uint64(0)
	if len(seqs) > 0 {
		startSeq = slices.Min(seqs)
	}

	events, err := listEvents(tx, startSeq)
	if err != nil {
		return err
	}

	for _, p := range projections {
		p.Update(events)
		if err := p.SaveSnapshot(tx); err != nil {
			return err
		}
	}

	return nil
}