import 'dart:convert';
import 'dart:typed_data';

import 'package:flutter_test/flutter_test.dart';
import 'package:halkyon_app/halkyon_app.dart';
import 'package:halkyon_base_client/halkyon_base_client.dart' as protocol;
import 'package:halkyon_llm/halkyon_llm.dart';
import 'package:serverpod_client/serverpod_client.dart';

// The conversation as features speak it (halkyon_llm's) and as the
// module's endpoint carries it (Halkyon Learn's ADR 0021, point 7): every
// part goes and comes back as it was, and the instance's refusals arrive as
// the app's failures.

final _image = Uint8List.fromList([0x89, 0x50, 0x4e, 0x47]);

LlmRequest _request() => LlmRequest(
  system: 'You help with flashcards.',
  maxOutputTokens: 800,
  personId: 'never sent from here',
  tools: const [
    LlmTool(
      name: 'find_cards',
      description: 'Finds cards',
      inputSchema: {
        'type': 'object',
        'properties': {
          'query': {'type': 'string'},
        },
      },
    ),
  ],
  messages: [
    LlmMessage.user([
      const LlmText('What does 猫 mean?'),
      LlmImage(mediaType: 'image/png', bytes: _image),
    ]),
    LlmMessage.assistant(const [
      LlmProviderBlock(
        protocol: LlmProtocol.anthropic,
        block: {'type': 'thinking', 'thinking': '…', 'signature': 'sig'},
      ),
      LlmText('Looking it up.', extra: {'phase': 'commentary'}),
      LlmToolCall(
        id: 'call_1',
        name: 'find_cards',
        input: {'query': '猫'},
        extra: {'id': 'fc_1'},
      ),
    ]),
    LlmMessage.user(const [
      LlmToolResult(callId: 'call_1', content: 'No card holds it.'),
      LlmToolResult(callId: 'call_2', content: 'Timed out', isError: true),
    ]),
  ],
);

void main() {
  group('questionOf', () {
    test(
      'carries the system prompt, the tools, the ceiling and every part',
      () {
        final question = questionOf('claude', _request());
        expect(question.assistant, 'claude');
        expect(question.system, 'You help with flashcards.');
        expect(question.maxOutputTokens, 800);
        expect(question.tools.single.name, 'find_cards');
        expect(jsonDecode(question.tools.single.inputSchema), {
          'type': 'object',
          'properties': {
            'query': {'type': 'string'},
          },
        });
        final [asked, thought, results] = question.messages;
        expect(asked.role, protocol.AssistantRole.user);
        expect(asked.parts.first.text, 'What does 猫 mean?');
        expect(asked.parts.last.kind, protocol.AssistantPartKind.image);
        expect(asked.parts.last.mediaType, 'image/png');
        expect(
          Uint8List.sublistView(asked.parts.last.bytes!),
          orderedEquals(_image),
        );
        expect(thought.role, protocol.AssistantRole.assistant);
        expect(thought.parts[0].kind, protocol.AssistantPartKind.providerBlock);
        expect(thought.parts[0].protocol, 'anthropic');
        expect(jsonDecode(thought.parts[1].extra!), {'phase': 'commentary'});
        expect(thought.parts[2].callId, 'call_1');
        expect(jsonDecode(thought.parts[2].json!), {'query': '猫'});
        expect(results.parts.last.isError, isTrue);
      },
    );

    test("leaves out the person's ID: the instance gives its own (D30)", () {
      final json = jsonEncode(questionOf('claude', _request()).toJson());
      expect(json, isNot(contains('never sent from here')));
    });
  });

  test('a turn goes and comes back as it was, every part', () {
    final request = _request();
    for (final message in request.messages) {
      final back = llmMessageOf(messageOf(message));
      expect(back.role, message.role);
      expect(
        jsonEncode(messageOf(back).toJson()),
        jsonEncode(messageOf(message).toJson()),
      );
    }
  });

  group('llmMessageOf refuses', () {
    test('a turn without parts', () {
      expect(
        () => llmMessageOf(
          protocol.AssistantMessage(
            role: protocol.AssistantRole.assistant,
            parts: [],
          ),
        ),
        throwsFormatException,
      );
    });

    test("a part out of its role's turn", () {
      expect(
        () => llmMessageOf(
          protocol.AssistantMessage(
            role: protocol.AssistantRole.assistant,
            parts: [
              protocol.AssistantPart(
                kind: protocol.AssistantPartKind.toolResult,
                callId: 'call_1',
                text: 'Done',
              ),
            ],
          ),
        ),
        throwsFormatException,
      );
    });

    test('a part without what its kind needs, or of a protocol unknown', () {
      for (final part in [
        protocol.AssistantPart(kind: protocol.AssistantPartKind.text),
        protocol.AssistantPart(
          kind: protocol.AssistantPartKind.providerBlock,
          protocol: 'gopher',
          json: '{}',
        ),
        protocol.AssistantPart(
          kind: protocol.AssistantPartKind.toolCall,
          callId: 'call_1',
          name: 'find_cards',
          json: '[1]',
        ),
      ]) {
        expect(
          () => llmMessageOf(
            protocol.AssistantMessage(
              role: protocol.AssistantRole.assistant,
              parts: [part],
            ),
          ),
          throwsFormatException,
          reason: part.kind.name,
        );
      }
    });
  });

  group('eventsOf', () {
    protocol.AssistantAnswer finished() => protocol.AssistantAnswer(
      message: protocol.AssistantMessage(
        role: protocol.AssistantRole.assistant,
        parts: [
          protocol.AssistantPart(
            kind: protocol.AssistantPartKind.text,
            text: 'Cat.',
          ),
        ],
      ),
      stop: protocol.AssistantStop.end,
      inputTokens: 12,
      outputTokens: 3,
    );

    test(
      'turns the pieces into text, then the whole turn with its tokens',
      () async {
        final events = await eventsOf(
          Stream.fromIterable([
            protocol.AssistantAnswer(delta: 'Ca'),
            protocol.AssistantAnswer(delta: ''),
            protocol.AssistantAnswer(delta: 't.'),
            finished(),
          ]),
        ).toList();
        expect(events, hasLength(3));
        expect((events[0] as LlmTextDelta).text, 'Ca');
        expect((events[1] as LlmTextDelta).text, 't.');
        final last = events[2] as LlmFinished;
        expect(last.message.text, 'Cat.');
        expect(last.stop, LlmStop.end);
        expect(last.usage, const LlmUsage(inputTokens: 12, outputTokens: 3));
      },
    );

    test('fails where the answer ends without its turn', () {
      expect(
        eventsOf(Stream.fromIterable([protocol.AssistantAnswer(delta: 'Ca')])),
        emitsInOrder([
          isA<LlmTextDelta>(),
          emitsError(const AssistantFailed(AssistantProblem.failed)),
          emitsDone,
        ]),
      );
    });

    test("fails where the turn isn't one, once", () {
      expect(
        eventsOf(
          Stream.fromIterable([
            protocol.AssistantAnswer(
              message: protocol.AssistantMessage(
                role: protocol.AssistantRole.assistant,
                parts: [],
              ),
            ),
          ]),
        ),
        emitsInOrder([
          emitsError(const AssistantFailed(AssistantProblem.providerFailed)),
          emitsDone,
        ]),
      );
    });

    test(
      "turns the instance's refusal into the app's, with when it resets",
      () {
        final resets = DateTime.utc(2026, 10, 26);
        expect(
          eventsOf(
            Stream.error(
              protocol.AssistantRefusedException(
                refusal: protocol.AssistantRefusal.limitReached,
                resetsAt: resets,
              ),
            ),
          ),
          emitsInOrder([
            emitsError(
              AssistantFailed(AssistantProblem.limitReached, resetsAt: resets),
            ),
            emitsDone,
          ]),
        );
      },
    );
  });

  group('failureOf', () {
    test('names every refusal of the instance as the app does', () {
      for (final (refusal, problem) in [
        (protocol.AssistantRefusal.notGranted, AssistantProblem.notGranted),
        (protocol.AssistantRefusal.notAgreed, AssistantProblem.notAgreed),
        (protocol.AssistantRefusal.limitReached, AssistantProblem.limitReached),
        (
          protocol.AssistantRefusal.invalidEffort,
          AssistantProblem.invalidEffort,
        ),
        (
          protocol.AssistantRefusal.imagesNotRead,
          AssistantProblem.imagesNotRead,
        ),
        (protocol.AssistantRefusal.malformed, AssistantProblem.malformed),
        (protocol.AssistantRefusal.tooLarge, AssistantProblem.tooLarge),
        (
          protocol.AssistantRefusal.tooManyAtOnce,
          AssistantProblem.tooManyAtOnce,
        ),
        (protocol.AssistantRefusal.providerKey, AssistantProblem.providerKey),
        (protocol.AssistantRefusal.providerBusy, AssistantProblem.providerBusy),
        (
          protocol.AssistantRefusal.providerRefused,
          AssistantProblem.providerRefused,
        ),
        (
          protocol.AssistantRefusal.providerFailed,
          AssistantProblem.providerFailed,
        ),
      ]) {
        expect(
          failureOf(protocol.AssistantRefusedException(refusal: refusal)),
          AssistantFailed(problem),
          reason: refusal.name,
        );
      }
    });

    test('keeps how long to wait', () {
      expect(
        failureOf(
          protocol.AssistantRefusedException(
            refusal: protocol.AssistantRefusal.providerBusy,
            retryAfterSeconds: 30,
          ),
        ),
        const AssistantFailed(
          AssistantProblem.providerBusy,
          retryAfter: Duration(seconds: 30),
        ),
      );
    });

    test('names a session without the scope, or none, not allowed', () {
      expect(
        failureOf(ServerpodClientUnauthorized()),
        const AssistantFailed(AssistantProblem.notAllowed),
      );
      expect(
        failureOf(ServerpodClientForbidden()),
        const AssistantFailed(AssistantProblem.notAllowed),
      );
    });

    test('names anything else failed', () {
      expect(
        failureOf(const SocketLikeException()),
        const AssistantFailed(AssistantProblem.failed),
      );
    });
  });

  test("ownKeyFailureOf names a personal key's provider's failures", () {
    for (final (kind, problem) in [
      (LlmFailureKind.key, AssistantProblem.providerKey),
      (LlmFailureKind.rateLimited, AssistantProblem.providerBusy),
      (LlmFailureKind.unavailable, AssistantProblem.providerBusy),
      (LlmFailureKind.request, AssistantProblem.providerRefused),
      (LlmFailureKind.provider, AssistantProblem.providerFailed),
      (LlmFailureKind.malformed, AssistantProblem.providerFailed),
      (LlmFailureKind.network, AssistantProblem.failed),
    ]) {
      expect(
        ownKeyFailureOf(LlmFailure(kind: kind, detail: 'detail')).problem,
        problem,
        reason: kind.name,
      );
    }
  });
}

/// A failure to reach the instance, as the network gives one.
final class const SocketLikeException() implements Exception;