cyberhybridhub/server/lib/questions_db.dart

410 lines
12 KiB
Dart

import 'dart:convert';
import 'dart:math';
import 'package:postgres/postgres.dart';
import 'package:uuid/uuid.dart';
/// Postgres access for the questions table.
class QuestionsDb {
QuestionsDb(this._connection);
final Connection _connection;
static const Uuid _uuid = Uuid();
Future<void> ensureUserExists(String firebaseUid) async {
await _connection.execute(
Sql.named(
'''
INSERT INTO users (firebase_uid)
VALUES (@uid)
ON CONFLICT (firebase_uid) DO NOTHING
''',
),
parameters: <String, dynamic>{'uid': firebaseUid},
);
}
/// Latest unanswered question for [assignedUserId], or null if none.
Future<Map<String, dynamic>?> findUnansweredQuestion(
String assignedUserId,
) async {
final Result result = await _connection.execute(
Sql.named(
'''
SELECT id, assigned_user_id, question_text, user_response, correct_answer,
created_at, modified_at, source_tag, pipeline_key, pipeline_step
FROM questions
WHERE assigned_user_id = @uid AND user_response IS NULL
ORDER BY created_at ASC
LIMIT 1
''',
),
parameters: <String, dynamic>{'uid': assignedUserId},
);
if (result.isEmpty) {
return null;
}
return _rowFromResult(result.first);
}
/// All unanswered questions for [assignedUserId], oldest first.
Future<List<Map<String, dynamic>>> listUnansweredQuestions(
String assignedUserId,
) async {
final Result result = await _connection.execute(
Sql.named(
'''
SELECT id, assigned_user_id, question_text, user_response, correct_answer,
created_at, modified_at, source_tag, pipeline_key, pipeline_step
FROM questions
WHERE assigned_user_id = @uid AND user_response IS NULL
ORDER BY created_at ASC
''',
),
parameters: <String, dynamic>{'uid': assignedUserId},
);
return result.map(_rowFromResult).toList();
}
/// Records [userResponse] for an unanswered question owned by [assignedUserId].
Future<Map<String, dynamic>?> submitAnswer({
required String questionId,
required String assignedUserId,
required num userResponse,
}) async {
final DateTime now = DateTime.now().toUtc();
final Result result = await _connection.execute(
Sql.named(
'''
UPDATE questions
SET user_response = @user_response, modified_at = @modified_at
WHERE id = @id::uuid
AND assigned_user_id = @uid
AND user_response IS NULL
RETURNING id, assigned_user_id, question_text, user_response, correct_answer,
created_at, modified_at, source_tag, pipeline_key, pipeline_step
''',
),
parameters: <String, dynamic>{
'id': questionId,
'uid': assignedUserId,
'user_response': userResponse,
'modified_at': now,
},
);
if (result.isEmpty) {
return null;
}
return _rowFromResult(result.first);
}
/// All Firebase UIDs that have a profile row (pipeline targets).
Future<List<String>> listAllUserFirebaseUids() async {
final Result result = await _connection.execute(
'SELECT firebase_uid FROM users ORDER BY updated_at DESC',
);
return result
.map((ResultRow row) => row[0]! as String)
.toList();
}
Future<Map<String, dynamic>?> getPipelineState(String assignedUserId) async {
final Result result = await _connection.execute(
Sql.named(
'''
SELECT pipeline_key, step, context, updated_at
FROM user_pipeline_state
WHERE assigned_user_id = @uid
''',
),
parameters: <String, dynamic>{'uid': assignedUserId},
);
if (result.isEmpty) {
return null;
}
final ResultRow row = result.first;
final Object? contextRaw = row[2];
final Map<String, dynamic> context = contextRaw is Map<String, dynamic>
? contextRaw
: jsonDecode(contextRaw.toString()) as Map<String, dynamic>;
return <String, dynamic>{
'assignedUserId': assignedUserId,
'pipelineKey': row[0]! as String,
'step': row[1]! as String,
'context': context,
'updatedAt': (row[3]! as DateTime).toIso8601String(),
};
}
Future<void> upsertPipelineState({
required String assignedUserId,
required String pipelineKey,
required String step,
required Map<String, dynamic> context,
}) async {
await ensureUserExists(assignedUserId);
final DateTime now = DateTime.now().toUtc();
await _connection.execute(
Sql.named(
'''
INSERT INTO user_pipeline_state (
assigned_user_id, pipeline_key, step, context, updated_at
) VALUES (
@uid, @pipeline_key, @step, @context::jsonb, @updated_at
)
ON CONFLICT (assigned_user_id) DO UPDATE SET
pipeline_key = EXCLUDED.pipeline_key,
step = EXCLUDED.step,
context = EXCLUDED.context,
updated_at = EXCLUDED.updated_at
''',
),
parameters: <String, dynamic>{
'uid': assignedUserId,
'pipeline_key': pipelineKey,
'step': step,
'context': jsonEncode(context),
'updated_at': now,
},
);
}
/// Moves an unanswered question to the end of the user's queue.
Future<Map<String, dynamic>?> deferQuestion({
required String questionId,
required String assignedUserId,
}) async {
final DateTime now = DateTime.now().toUtc();
final Result result = await _connection.execute(
Sql.named(
'''
UPDATE questions q
SET created_at = sub.max_ts + INTERVAL '1 millisecond',
modified_at = @modified_at
FROM (
SELECT COALESCE(MAX(created_at), @modified_at) AS max_ts
FROM questions
WHERE assigned_user_id = @uid AND user_response IS NULL
) sub
WHERE q.id = @id::uuid
AND q.assigned_user_id = @uid
AND q.user_response IS NULL
RETURNING q.id, q.assigned_user_id, q.question_text, q.user_response,
q.correct_answer, q.created_at, q.modified_at,
q.source_tag, q.pipeline_key, q.pipeline_step
''',
),
parameters: <String, dynamic>{
'id': questionId,
'uid': assignedUserId,
'modified_at': now,
},
);
if (result.isEmpty) {
return null;
}
return _rowFromResult(result.first);
}
/// Count of unanswered questions assigned to [assignedUserId].
Future<int> countUnansweredQuestions(String assignedUserId) async {
final Result result = await _connection.execute(
Sql.named(
'''
SELECT COUNT(*)::int AS count
FROM questions
WHERE assigned_user_id = @uid AND user_response IS NULL
''',
),
parameters: <String, dynamic>{'uid': assignedUserId},
);
return (result.first[0]! as num).toInt();
}
/// Returns an existing unanswered question or creates the starter question.
Future<Map<String, dynamic>> getOrCreateStarterQuestion(
String assignedUserId,
) async {
final Map<String, dynamic>? existing =
await findUnansweredQuestion(assignedUserId);
if (existing != null) {
return existing;
}
return createStarterQuestion(assignedUserId);
}
/// Creates the starter test question with a random correct answer in [-10, 10].
Future<Map<String, dynamic>> createStarterQuestion(String assignedUserId) async {
await ensureUserExists(assignedUserId);
final int correctAnswer = Random().nextInt(21) - 10;
final String id = _uuid.v4();
final DateTime now = DateTime.now().toUtc();
const String questionText =
'Starter question: enter a whole number between -10 and 10.';
await _connection.execute(
Sql.named(
'''
INSERT INTO questions (
id, assigned_user_id, question_text, user_response, correct_answer,
created_at, modified_at
) VALUES (
@id::uuid, @assigned_user_id, @question_text, NULL, @correct_answer,
@created_at, @modified_at
)
''',
),
parameters: <String, dynamic>{
'id': id,
'assigned_user_id': assignedUserId,
'question_text': questionText,
'correct_answer': correctAnswer,
'created_at': now,
'modified_at': now,
},
);
return <String, dynamic>{
'id': id,
'assignedUserId': assignedUserId,
'text': questionText,
'userResponse': null,
'correctAnswer': correctAnswer,
'createdAt': now.toIso8601String(),
'modifiedAt': now.toIso8601String(),
};
}
Future<Map<String, dynamic>> createQuestion({
required String assignedUserId,
required String questionText,
required num correctAnswer,
String? sourceTag,
String? pipelineKey,
String? pipelineStep,
}) async {
await ensureUserExists(assignedUserId);
final String id = _uuid.v4();
final DateTime now = DateTime.now().toUtc();
await _connection.execute(
Sql.named(
'''
INSERT INTO questions (
id, assigned_user_id, question_text, user_response, correct_answer,
created_at, modified_at, source_tag, pipeline_key, pipeline_step
) VALUES (
@id::uuid, @assigned_user_id, @question_text, NULL, @correct_answer,
@created_at, @modified_at, @source_tag, @pipeline_key, @pipeline_step
)
''',
),
parameters: <String, dynamic>{
'id': id,
'assigned_user_id': assignedUserId,
'question_text': questionText,
'correct_answer': correctAnswer,
'created_at': now,
'modified_at': now,
'source_tag': sourceTag,
'pipeline_key': pipelineKey,
'pipeline_step': pipelineStep,
},
);
return _rowToJson(
id: id,
assignedUserId: assignedUserId,
questionText: questionText,
userResponse: null,
correctAnswer: correctAnswer,
createdAt: now,
modifiedAt: now,
sourceTag: sourceTag,
pipelineKey: pipelineKey,
pipelineStep: pipelineStep,
);
}
/// Payload sent to the Flutter client over SignalR (excludes correct answer).
Map<String, dynamic> toClientPayload(
Map<String, dynamic> question, {
required int unansweredCount,
}) {
return <String, dynamic>{
'id': question['id'],
'assignedUserId': question['assignedUserId'],
'text': question['text'],
'sentAt': question['createdAt'],
'unansweredCount': unansweredCount,
};
}
Map<String, dynamic> _rowFromResult(ResultRow row) {
final Object idValue = row[0]!;
final String id = idValue is String ? idValue : idValue.toString();
final DateTime createdAt = row[5]! as DateTime;
final DateTime modifiedAt = row[6]! as DateTime;
return _rowToJson(
id: id,
assignedUserId: row[1]! as String,
questionText: row[2]! as String,
userResponse: _readOptionalNumeric(row[3]),
correctAnswer: _readNumeric(row[4]),
createdAt: createdAt,
modifiedAt: modifiedAt,
sourceTag: row.length > 7 ? row[7] as String? : null,
pipelineKey: row.length > 8 ? row[8] as String? : null,
pipelineStep: row.length > 9 ? row[9] as String? : null,
);
}
/// Postgres NUMERIC columns may decode as [String] or [num].
static num _readNumeric(Object? value) {
if (value == null) {
return 0;
}
if (value is num) {
return value;
}
if (value is String) {
return num.parse(value);
}
return num.parse(value.toString());
}
static num? _readOptionalNumeric(Object? value) {
if (value == null) {
return null;
}
return _readNumeric(value);
}
Map<String, dynamic> _rowToJson({
required String id,
required String assignedUserId,
required String questionText,
required Object? userResponse,
required num correctAnswer,
required DateTime createdAt,
required DateTime modifiedAt,
String? sourceTag,
String? pipelineKey,
String? pipelineStep,
}) {
return <String, dynamic>{
'id': id,
'assignedUserId': assignedUserId,
'text': questionText,
'userResponse': userResponse,
'correctAnswer': correctAnswer,
'createdAt': createdAt.toIso8601String(),
'modifiedAt': modifiedAt.toIso8601String(),
if (sourceTag != null) 'sourceTag': sourceTag,
if (pipelineKey != null) 'pipelineKey': pipelineKey,
if (pipelineStep != null) 'pipelineStep': pipelineStep,
};
}
}