from __future__ import annotations

from memabra.app import build_demo_app
from memabra.benchmarks import BenchmarkTask
from memabra.dataset import DatasetBuilder
from memabra.evaluator import Evaluator
from memabra.online_learning import OnlineLearningCoordinator
from memabra.promotion import PromotionPolicy
from memabra.router_versioning import RouterVersionStore


def _seed_trajectories(app, count: int):
    for i in range(count):
        app.run_task(f"Test task {i}", channel="local")


def test_coordinator_skips_when_too_few_new_trajectories(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 2)

    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=PromotionPolicy(
            min_reward_delta=0.01,
            max_error_rate_increase=0.05,
            max_latency_increase_ms=100.0,
            required_task_count=1,
        ),
        benchmark_tasks=[BenchmarkTask(user_input="test")],
        min_new_trajectories=5,
    )

    result = coordinator.run_cycle()

    assert result["skipped"] is True
    assert "too few new trajectories" in result["reason"].lower()


def test_coordinator_rejects_when_policy_fails(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    # Seed enough trajectories for training and benchmarking
    _seed_trajectories(app, 10)

    # Use a very strict policy that will reject any challenger
    policy = PromotionPolicy(
        min_reward_delta=1.0,  # impossible to meet
        max_error_rate_increase=0.0,
        max_latency_increase_ms=0.0,
        required_task_count=1,
    )

    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=[BenchmarkTask(user_input="Test task 0")],
        min_new_trajectories=1,
        version_store_base_dir=tmp_path / "versions",
    )

    result = coordinator.run_cycle()

    assert result["skipped"] is False
    assert result["promoted"] is False
    assert "decision" in result
    assert result["decision"].accepted is False


def test_coordinator_accepts_and_saves_version_when_policy_passes(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 10)

    # Lenient policy that should pass
    policy = PromotionPolicy(
        min_reward_delta=-1.0,  # always passes
        max_error_rate_increase=1.0,
        max_latency_increase_ms=10000.0,
        required_task_count=1,
    )

    version_dir = tmp_path / "versions"
    report_dir = tmp_path / "reports"
    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=[BenchmarkTask(user_input="Test task 0")],
        min_new_trajectories=1,
        version_store_base_dir=version_dir,
        report_store_base_dir=report_dir,
    )

    result = coordinator.run_cycle()

    assert result["skipped"] is False
    assert result["promoted"] is True
    assert "version_id" in result
    assert result["decision"].accepted is True

    # Verify version was saved
    store = RouterVersionStore(base_dir=version_dir)
    versions = store.list_versions()
    assert len(versions) == 1
    assert versions[0]["version_id"] == result["version_id"]

    # Verify report was saved
    from memabra.training_reports import TrainingReportStore
    report_store = TrainingReportStore(base_dir=report_dir)
    reports = report_store.list_reports()
    assert len(reports) == 1
    assert reports[0]["promoted_version_id"] == result["version_id"]


def test_coordinator_saves_report_on_rejection(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 10)

    policy = PromotionPolicy(
        min_reward_delta=1.0,
        max_error_rate_increase=0.0,
        max_latency_increase_ms=0.0,
        required_task_count=1,
    )

    report_dir = tmp_path / "reports"
    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=[BenchmarkTask(user_input="Test task 0")],
        min_new_trajectories=1,
        report_store_base_dir=report_dir,
    )

    result = coordinator.run_cycle()

    assert result["promoted"] is False
    from memabra.training_reports import TrainingReportStore
    report_store = TrainingReportStore(base_dir=report_dir)
    reports = report_store.list_reports()
    assert len(reports) == 1
    assert reports[0]["promotion_decision"]["accepted"] is False


def test_coordinator_catches_training_exception_and_returns_error_report(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 10)

    policy = PromotionPolicy(
        min_reward_delta=-1.0,
        max_error_rate_increase=1.0,
        max_latency_increase_ms=10000.0,
        required_task_count=1,
    )

    report_dir = tmp_path / "reports"
    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=[BenchmarkTask(user_input="Test task 0")],
        min_new_trajectories=1,
        report_store_base_dir=report_dir,
    )

    # Force a training failure by monkeypatching DatasetBuilder.build to raise
    original_build = DatasetBuilder.build
    DatasetBuilder.build = lambda self, trajectories: (_ for _ in ()).throw(RuntimeError("simulated training failure"))

    try:
        result = coordinator.run_cycle()
    finally:
        DatasetBuilder.build = original_build

    assert result["skipped"] is False
    assert result["promoted"] is False
    assert "error" in result
    assert "simulated training failure" in result["error"]

    # Verify error report was saved
    from memabra.training_reports import TrainingReportStore
    report_store = TrainingReportStore(base_dir=report_dir)
    reports = report_store.list_reports()
    assert len(reports) == 1
    assert reports[0]["promotion_decision"]["accepted"] is False
    assert "simulated training failure" in reports[0]["promotion_decision"]["reasons"][0]


def test_coordinator_persists_seen_trajectory_ids_across_restarts(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 5)

    policy = PromotionPolicy(
        min_reward_delta=-1.0,
        max_error_rate_increase=1.0,
        max_latency_increase_ms=10000.0,
        required_task_count=1,
    )
    benchmark_tasks = [BenchmarkTask(user_input="Test task 0")]
    seen_store = tmp_path / "seen_trajectories.json"
    version_dir = tmp_path / "versions"
    report_dir = tmp_path / "reports"

    coordinator1 = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=benchmark_tasks,
        min_new_trajectories=1,
        version_store_base_dir=version_dir,
        report_store_base_dir=report_dir,
        seen_trajectory_store=seen_store,
    )
    result1 = coordinator1.run_cycle()
    assert result1["skipped"] is False

    # New coordinator instance pointing to same store
    coordinator2 = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=benchmark_tasks,
        min_new_trajectories=1,
        version_store_base_dir=version_dir,
        report_store_base_dir=report_dir,
        seen_trajectory_store=seen_store,
    )
    result2 = coordinator2.run_cycle()
    assert result2["skipped"] is True
    assert "too few new trajectories" in result2["reason"].lower()


def test_coordinator_dry_run_does_not_promote_or_save_version(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 10)

    policy = PromotionPolicy(
        min_reward_delta=-1.0,
        max_error_rate_increase=1.0,
        max_latency_increase_ms=10000.0,
        required_task_count=1,
    )

    version_dir = tmp_path / "versions"
    report_dir = tmp_path / "reports"
    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=[BenchmarkTask(user_input="Test task 0")],
        min_new_trajectories=1,
        version_store_base_dir=version_dir,
        report_store_base_dir=report_dir,
    )

    result = coordinator.run_cycle(dry_run=True)

    assert result["skipped"] is False
    assert result["promoted"] is False
    assert "decision" in result
    assert result["decision"].accepted is True  # policy would accept, but dry_run blocks promotion

    # No version should be saved
    store = RouterVersionStore(base_dir=version_dir)
    assert len(store.list_versions()) == 0

    # Report should still be saved for audit
    from memabra.training_reports import TrainingReportStore

    report_store = TrainingReportStore(base_dir=report_dir)
    reports = report_store.list_reports()
    assert len(reports) == 1
    assert reports[0].get("dry_run") is True


def test_coordinator_rebuilds_case_index_when_path_provided(tmp_path):
    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 10)

    policy = PromotionPolicy(
        min_reward_delta=-1.0,
        max_error_rate_increase=1.0,
        max_latency_increase_ms=10000.0,
        required_task_count=1,
    )

    case_index_path = tmp_path / "case-index.json"
    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=[BenchmarkTask(user_input="Test task 0")],
        min_new_trajectories=1,
        case_index_path=case_index_path,
    )

    result = coordinator.run_cycle()

    assert result["skipped"] is False
    assert case_index_path.exists()
    from memabra.case_index import CaseIndex

    index = CaseIndex.load(case_index_path)
    assert index.best("Test task 0") is not None


def test_coordinator_uses_specified_baseline_version(tmp_path):
    from memabra.router import SimpleLearningRouter

    app = build_demo_app(base_dir=tmp_path / "demo-artifacts")
    _seed_trajectories(app, 10)

    # Save a baseline version with known weights
    baseline_router = SimpleLearningRouter()
    baseline_router._weights = {"call_tool": {"input_length": 0.99}}
    baseline_router._feature_keys = ["input_length"]
    version_dir = tmp_path / "versions"
    store = RouterVersionStore(base_dir=version_dir)
    store.save(baseline_router, version_id="v-baseline", metadata={"note": "baseline"})

    # Change app's current router to something different
    different_router = SimpleLearningRouter()
    different_router._weights = {"clarify": {"input_length": 0.01}}
    different_router._feature_keys = ["input_length"]
    app.set_router(different_router)

    policy = PromotionPolicy(
        min_reward_delta=-1.0,
        max_error_rate_increase=1.0,
        max_latency_increase_ms=10000.0,
        required_task_count=1,
    )

    report_dir = tmp_path / "reports"
    coordinator = OnlineLearningCoordinator(
        app=app,
        policy=policy,
        benchmark_tasks=[BenchmarkTask(user_input="Test task 0")],
        min_new_trajectories=1,
        version_store_base_dir=version_dir,
        report_store_base_dir=report_dir,
    )

    result = coordinator.run_cycle(baseline_version_id="v-baseline")

    assert result["skipped"] is False
    assert "baseline_metrics" in result
    assert "challenger_metrics" in result

    # Verify report records the baseline version
    from memabra.training_reports import TrainingReportStore

    report_store = TrainingReportStore(base_dir=report_dir)
    reports = report_store.list_reports()
    assert len(reports) == 1
    assert reports[0].get("baseline_version_id") == "v-baseline"