"""Offline tests for the retry/backoff layer. No network, no real sleeping."""
import pytest
import requests

import bls_client.client as client_mod
from bls_client import BLSClient
from bls_client.retry import with_retries


class Resp:
    def __init__(self, status_code=200, headers=None):
        self.status_code = status_code
        self.headers = headers or {}

    def raise_for_status(self):
        pass

    def json(self):
        return {
            "status": "REQUEST_SUCCEEDED",
            "Results": {"series": [{"seriesID": "X", "data": [{"year": "2024", "period": "M01", "value": "1"}]}]},
        }


def _recorder():
    delays = []
    return delays, (lambda d: delays.append(d))


def test_retries_transient_exception_then_succeeds():
    calls = {"n": 0}
    delays, sleep = _recorder()

    def send():
        calls["n"] += 1
        if calls["n"] < 3:
            raise requests.exceptions.ConnectionError("boom")
        return Resp(200)

    resp = with_retries(send, retries=3, backoff=0.5, sleep=sleep)
    assert resp.status_code == 200
    assert calls["n"] == 3
    assert delays == [0.5, 1.0]            # exponential backoff between the 3 attempts


def test_gives_up_after_max_retries():
    delays, sleep = _recorder()

    def send():
        raise requests.exceptions.Timeout("slow")

    with pytest.raises(requests.exceptions.Timeout):
        with_retries(send, retries=2, backoff=0.5, sleep=sleep)
    assert len(delays) == 2                # retried twice, then re-raised


def test_retries_5xx_but_not_4xx():
    delays, sleep = _recorder()
    seq = [Resp(503), Resp(200)]
    resp = with_retries(lambda: seq.pop(0), retries=3, backoff=0.5, sleep=sleep)
    assert resp.status_code == 200 and len(delays) == 1

    delays2, sleep2 = _recorder()
    resp2 = with_retries(lambda: Resp(404), retries=3, backoff=0.5, sleep=sleep2)
    assert resp2.status_code == 404 and delays2 == []   # client error: not retried


def test_honors_retry_after_header():
    delays, sleep = _recorder()
    seq = [Resp(429, headers={"Retry-After": "7"}), Resp(200)]
    with_retries(lambda: seq.pop(0), retries=2, backoff=0.5, sleep=sleep)
    assert delays == [7.0]


def test_client_retries_then_succeeds(monkeypatch):
    # no real sleeping
    monkeypatch.setattr("bls_client.retry.time.sleep", lambda d: None)
    state = {"n": 0}

    def fake_post(url, json=None, timeout=None):
        state["n"] += 1
        if state["n"] == 1:
            raise requests.exceptions.ConnectionError("transient")
        return Resp(200)

    monkeypatch.setattr(client_mod.requests, "post", fake_post)
    c = BLSClient("key", retries=2)
    out = c.fetch(["CES0000000001"], 2024, 2024)
    assert out and state["n"] == 2          # failed once, retried, succeeded
    assert c.queries_used == 1              # counter only counts the successful POST


def test_retries_zero_disables(monkeypatch):
    monkeypatch.setattr("bls_client.retry.time.sleep", lambda d: None)

    def fake_post(url, json=None, timeout=None):
        raise requests.exceptions.ConnectionError("transient")

    monkeypatch.setattr(client_mod.requests, "post", fake_post)
    with pytest.raises(requests.exceptions.ConnectionError):
        BLSClient("key", retries=0).fetch(["CES0000000001"], 2024, 2024)