import os

from gateway.config import Platform
from gateway.run import GatewayRunner
from gateway.session import SessionContext, SessionSource
from gateway.session_context import (
    get_session_env,
    set_session_vars,
    clear_session_vars,
)


def test_set_session_env_sets_contextvars(monkeypatch):
    """_set_session_env should populate contextvars, not os.environ."""
    runner = object.__new__(GatewayRunner)
    source = SessionSource(
        platform=Platform.TELEGRAM,
        chat_id="-1001",
        chat_name="Group",
        chat_type="group",
        thread_id="17585",
    )
    context = SessionContext(source=source, connected_platforms=[], home_channels={})

    monkeypatch.delenv("HERMES_SESSION_PLATFORM", raising=False)
    monkeypatch.delenv("HERMES_SESSION_CHAT_ID", raising=False)
    monkeypatch.delenv("HERMES_SESSION_CHAT_NAME", raising=False)
    monkeypatch.delenv("HERMES_SESSION_THREAD_ID", raising=False)

    tokens = runner._set_session_env(context)

    # Values should be readable via get_session_env (contextvar path)
    assert get_session_env("HERMES_SESSION_PLATFORM") == "telegram"
    assert get_session_env("HERMES_SESSION_CHAT_ID") == "-1001"
    assert get_session_env("HERMES_SESSION_CHAT_NAME") == "Group"
    assert get_session_env("HERMES_SESSION_THREAD_ID") == "17585"

    # os.environ should NOT be touched
    assert os.getenv("HERMES_SESSION_PLATFORM") is None
    assert os.getenv("HERMES_SESSION_THREAD_ID") is None

    # Clean up
    runner._clear_session_env(tokens)


def test_clear_session_env_restores_previous_state(monkeypatch):
    """_clear_session_env should restore contextvars to their pre-handler values."""
    runner = object.__new__(GatewayRunner)

    monkeypatch.delenv("HERMES_SESSION_PLATFORM", raising=False)
    monkeypatch.delenv("HERMES_SESSION_CHAT_ID", raising=False)
    monkeypatch.delenv("HERMES_SESSION_CHAT_NAME", raising=False)
    monkeypatch.delenv("HERMES_SESSION_THREAD_ID", raising=False)

    source = SessionSource(
        platform=Platform.TELEGRAM,
        chat_id="-1001",
        chat_name="Group",
        chat_type="group",
        thread_id="17585",
    )
    context = SessionContext(source=source, connected_platforms=[], home_channels={})

    tokens = runner._set_session_env(context)
    assert get_session_env("HERMES_SESSION_PLATFORM") == "telegram"

    runner._clear_session_env(tokens)

    # After clear, contextvars should return to defaults (empty)
    assert get_session_env("HERMES_SESSION_PLATFORM") == ""
    assert get_session_env("HERMES_SESSION_CHAT_ID") == ""
    assert get_session_env("HERMES_SESSION_CHAT_NAME") == ""
    assert get_session_env("HERMES_SESSION_THREAD_ID") == ""


def test_get_session_env_falls_back_to_os_environ(monkeypatch):
    """get_session_env should fall back to os.environ when contextvar is unset."""
    monkeypatch.setenv("HERMES_SESSION_PLATFORM", "discord")

    # No contextvar set — should read from os.environ
    assert get_session_env("HERMES_SESSION_PLATFORM") == "discord"

    # Now set a contextvar — should prefer it
    tokens = set_session_vars(platform="telegram")
    assert get_session_env("HERMES_SESSION_PLATFORM") == "telegram"

    # Restore — should fall back to os.environ again
    clear_session_vars(tokens)
    assert get_session_env("HERMES_SESSION_PLATFORM") == "discord"


def test_get_session_env_default_when_nothing_set(monkeypatch):
    """get_session_env returns default when neither contextvar nor env is set."""
    monkeypatch.delenv("HERMES_SESSION_PLATFORM", raising=False)

    assert get_session_env("HERMES_SESSION_PLATFORM") == ""
    assert get_session_env("HERMES_SESSION_PLATFORM", "fallback") == "fallback"


def test_set_session_env_handles_missing_optional_fields():
    """_set_session_env should handle None chat_name and thread_id gracefully."""
    runner = object.__new__(GatewayRunner)
    source = SessionSource(
        platform=Platform.TELEGRAM,
        chat_id="-1001",
        chat_name=None,
        chat_type="private",
        thread_id=None,
    )
    context = SessionContext(source=source, connected_platforms=[], home_channels={})

    tokens = runner._set_session_env(context)

    assert get_session_env("HERMES_SESSION_PLATFORM") == "telegram"
    assert get_session_env("HERMES_SESSION_CHAT_ID") == "-1001"
    assert get_session_env("HERMES_SESSION_CHAT_NAME") == ""
    assert get_session_env("HERMES_SESSION_THREAD_ID") == ""

    runner._clear_session_env(tokens)