"""Plan 03-02 Task 2 Step 7: M6 context-repeat-rate LIVE tests."""
from __future__ import annotations

import pytest

from iai_mcp.events import write_event
from iai_mcp.store import MemoryStore
from iai_mcp.trajectory import m6_context_repeat_rate_live


def test_m6_zero_on_empty_store(tmp_path):
    store = MemoryStore(path=tmp_path)
    assert m6_context_repeat_rate_live(store) == 0.0


def test_m6_repeat_rate_three_repeats_in_ten(tmp_path):
    """10 sessions, 3 repeated hashes -> repeat rate 0.3.

    Layout: 7 distinct hashes + 3 reuses of one prior hash.
    total=10, unique=7, (10-7)/10 = 0.3.
    """
    store = MemoryStore(path=tmp_path)
    distinct = [f"h{i}" for i in range(7)]
    for h in distinct:
        write_event(
            store, kind="session_started",
            data={"session_state_hash": h, "session_id": "s"},
            severity="info",
        )
    # 3 reuses of "h0"
    for _ in range(3):
        write_event(
            store, kind="session_started",
            data={"session_state_hash": "h0", "session_id": "s"},
            severity="info",
        )
    val = m6_context_repeat_rate_live(store)
    assert val == pytest.approx(0.3, abs=1e-6)


def test_m6_all_unique_returns_zero(tmp_path):
    store = MemoryStore(path=tmp_path)
    for i in range(5):
        write_event(
            store, kind="session_started",
            data={"session_state_hash": f"u{i}"},
            severity="info",
        )
    assert m6_context_repeat_rate_live(store) == 0.0


def test_m6_all_repeats_returns_high(tmp_path):
    store = MemoryStore(path=tmp_path)
    for _ in range(5):
        write_event(
            store, kind="session_started",
            data={"session_state_hash": "same"},
            severity="info",
        )
    val = m6_context_repeat_rate_live(store)
    assert val == pytest.approx(0.8, abs=1e-6)  # (5-1)/5