from __future__ import annotations

from pathlib import Path

import pytest

from app.observability.config import get_observability_config

ENV_VARS = (
    "OTEL_ENABLED",
    "OTEL_MODE",
    "OTEL_EXPORTER_OTLP_ENDPOINT",
    "SIGNOZ_UI_URL",
    "OBSERVABILITY_ARTIFACT_ROOT",
    "EVALUATION_RUN",
    "DEPLOYMENT_ENV",
)


@pytest.fixture(autouse=True)
def clean_observability_env(monkeypatch):
    """Every test starts from a clean slate regardless of the host shell's env."""
    for name in ENV_VARS:
        monkeypatch.delenv(name, raising=False)
    yield


def test_defaults_when_env_unset():
    config = get_observability_config()

    assert config.enabled is False
    assert config.mode == "disabled"
    assert config.otlp_endpoint == "http://127.0.0.1:4318"
    assert config.signoz_ui_url == "http://127.0.0.1:8080"
    assert config.artifact_root == Path("~/.studybuddy/observability").expanduser()


def test_reads_all_env_vars(monkeypatch, tmp_path):
    monkeypatch.setenv("OTEL_ENABLED", "true")
    monkeypatch.setenv("OTEL_MODE", "local")
    monkeypatch.setenv("OTEL_EXPORTER_OTLP_ENDPOINT", "http://collector.internal:4318")
    monkeypatch.setenv("SIGNOZ_UI_URL", "http://signoz.internal:8080")
    monkeypatch.setenv("OBSERVABILITY_ARTIFACT_ROOT", str(tmp_path))

    config = get_observability_config()

    assert config.enabled is True
    assert config.mode == "local"
    assert config.otlp_endpoint == "http://collector.internal:4318"
    assert config.signoz_ui_url == "http://signoz.internal:8080"
    assert config.artifact_root == tmp_path


def test_demo_deployment_forces_observability_off(monkeypatch):
    monkeypatch.setenv("DEPLOYMENT_ENV", "demo")
    monkeypatch.setenv("OTEL_ENABLED", "true")
    monkeypatch.setenv("OTEL_MODE", "full")

    config = get_observability_config()

    assert config.enabled is False
    assert config.mode == "disabled"


def test_artifact_root_expands_user_home(monkeypatch):
    monkeypatch.setenv("OBSERVABILITY_ARTIFACT_ROOT", "~/.studybuddy/observability")

    config = get_observability_config()

    assert "~" not in str(config.artifact_root)
    assert config.artifact_root == Path("~/.studybuddy/observability").expanduser()


@pytest.mark.parametrize("raw,expected", [("true", True), ("1", True), ("yes", True), ("on", True), ("True", True)])
def test_otel_enabled_truthy_strings(monkeypatch, raw, expected):
    monkeypatch.setenv("OTEL_ENABLED", raw)
    assert get_observability_config().enabled is expected


@pytest.mark.parametrize("raw,expected", [("false", False), ("0", False), ("no", False), ("off", False), ("", False)])
def test_otel_enabled_falsy_strings(monkeypatch, raw, expected):
    monkeypatch.setenv("OTEL_ENABLED", raw)
    assert get_observability_config().enabled is expected


def test_invalid_mode_falls_back_to_disabled_in_ordinary_startup(monkeypatch):
    monkeypatch.setenv("OTEL_MODE", "bogus-mode")

    config = get_observability_config()

    assert config.mode == "disabled"


def test_invalid_mode_raises_descriptive_error_in_evaluation_run(monkeypatch):
    monkeypatch.setenv("OTEL_MODE", "bogus-mode")
    monkeypatch.setenv("EVALUATION_RUN", "true")

    with pytest.raises(ValueError, match="bogus-mode"):
        get_observability_config()


def test_missing_mode_defaults_to_disabled_in_evaluation_run(monkeypatch):
    # No OTEL_MODE set at all -> defaults to "disabled". A benchmark run
    # explicitly opting out of telemetry is a valid choice, not a
    # misconfiguration, so this must not raise.
    monkeypatch.setenv("EVALUATION_RUN", "true")

    config = get_observability_config()

    assert config.mode == "disabled"


def test_explicit_disabled_mode_does_not_raise_in_evaluation_run(monkeypatch):
    monkeypatch.setenv("OTEL_MODE", "disabled")
    monkeypatch.setenv("EVALUATION_RUN", "true")

    config = get_observability_config()

    assert config.mode == "disabled"


def test_bogus_mode_still_raises_in_evaluation_run(monkeypatch):
    monkeypatch.setenv("OTEL_MODE", "bogus-garbage")
    monkeypatch.setenv("EVALUATION_RUN", "true")

    with pytest.raises(ValueError, match="bogus-garbage"):
        get_observability_config()


def test_valid_mode_with_evaluation_run_succeeds(monkeypatch):
    monkeypatch.setenv("OTEL_MODE", "full")
    monkeypatch.setenv("EVALUATION_RUN", "true")

    config = get_observability_config()

    assert config.mode == "full"


def test_local_mode_with_evaluation_run_succeeds(monkeypatch):
    monkeypatch.setenv("OTEL_MODE", "local")
    monkeypatch.setenv("EVALUATION_RUN", "true")

    config = get_observability_config()

    assert config.mode == "local"