"""Phase 67 E2E (Playwright): LLM retry with live "Trying Again" feedback.

Source: ``TODO.md`` L3 — "Add a .env configurable retry in case the LLM
server fails to respond. Allow 3 retries by default, with 5 seconds
between each retry. Update the user interface to show 'communication
interrupted, trying again' … if the LLM server stops communicating."
(TODO-derived phase — no story file.)
Run in isolation (DB must be up: ``podman compose up -d db``):

    uv run pytest tests/e2e/test_llm_retry.py -v --no-cov

MOCK-ONLY suite: ``E2E_REAL_LLM=1`` is not supported — the retry gate is
the deterministic failure injection in ``tests/e2e/mock_llm.py``:

* ``fail then answer`` (``RETRY_TRIGGER``): the first 2 app-level
  streaming attempts 500 (JSON body, like a dead proxy) and the third
  streams the normal composed answer — 1 original attempt + 1 retry
  under the default ``BOR_LLM_RETRIES=3``. (Each dead app attempt costs
  3 HTTP POSTs — the openai SDK's default 1 + 2 internal retries — so
  the mock counts attempts, not POSTs; see the mock docstring.)
* ``always fail`` (``ALWAYS_FAIL_TRIGGER``): every streaming request
  500s — the retry-budget exhaustion path.
* ``embed fail once`` (``EMBED_FAIL_TRIGGER``): the first embeddings
  request 500s, the next returns the normal vector — the endpoint's
  pre-stream embedding retry loop.

The e2e app server boots with ``BOR_LLM_RETRY_DELAY=0`` (conftest) so
the retry waits are instant — the suite pins the MECHANISM; the 5 s
default is unit-pinned via ``tests/unit/test_config.py``.
``BOR_LLM_RETRIES`` is forced to its real default (3, conftest) — the
exhaustion test relies on the real budget: 4 attempts total, so the
last ``retry`` frame reads "(4 of 4)".

KB seed (phase-37 direct-seed pattern): ONE fixture document
(``homelab/kubernetes.md``), one chunk carrying the mock's own
bag-of-words embedding. The marker questions were verified against this
exact seed (``plan_turn``, E2E threshold 0.30):

* the "sourdough" questions (DEFLECT_Q / EXHAUST_Q) share no FTS token
  with the document (cosine 0.000, fts 0) → LOW → the DEFLECTED path
  (``chat_stream_retried`` directly, no agent round);
* the "kubernetes cluster" questions (GROUNDED_Q / EMBED_Q) FTS-hit the
  document (cosine 0.171, fts 1) → HIGH → the GROUNDED path (the agent
  loop's per-round retry).

Test → source mapping:
1. ``test_dead_then_recovered_deflected`` — LOW turn: the recorded
   ``#send-status`` values contain "Communication interrupted —
   retrying (2 of 4)…" and "(3 of 4)…" (the owner-locked A4 copy), the
   wire carries the two ``retry`` frames ahead of the first delta, the
   deflected answer settles, and no error banner appears.
2. ``test_dead_then_recovered_grounded`` — HIGH turn: the same status +
   wire assertions; the grounded answer completes with the source chip
   (the agent round retried, the turn is intact).
3. ``test_embedding_retry_completes`` — ``embed fail once``: the
   pre-stream embedding retry is visible to the UI (a ``retry`` status
   before any answer frame) and the turn completes normally.
4. ``test_exhaustion_lands_on_the_error_banner`` — ``always fail``:
   after the 4th dead attempt the EXISTING terminal error banner
   appears (role=alert, the "dropped the connection" copy), the last
   retrying status is the highest attempt — "(4 of 4)…" — and the send
   button re-enables (the banner path settles the state machine).
"""
from __future__ import annotations

import hashlib
import json
import re
import time
from datetime import UTC, datetime
from pathlib import Path

from playwright.sync_api import Page, expect
from sqlalchemy import select, text
from sqlalchemy.orm import Session

from app.db import SessionLocal
from app.models import Chunk, Document, QueryLog
from e2e.auth_helpers import login
from tests.e2e.mock_llm import embed_text

REPO = Path(__file__).resolve().parents[2]

# --------------------------------------------------------------------------
# Seed + questions (see the module docstring for the gate verification)
# --------------------------------------------------------------------------

SEED_SOURCE = "docs"
SEED_PATH = "homelab/kubernetes.md"
SEED_SP = f"{SEED_SOURCE}/{SEED_PATH}"
KUB_CONTENT = (REPO / "tests" / "fixtures" / "docs" / SEED_PATH).read_text()

#: LOW turn (deflected path) + the retry trigger: no FTS overlap with the
#: seeded document, cosine 0.000 → the honesty gate deflects.
DEFLECT_Q = "How do I bake sourdough bread? fail then answer"
#: HIGH turn (grounded path) + the retry trigger: FTS-hits the seeded
#: document → the agent loop runs (and its single round is retried).
GROUNDED_Q = "How is my Kubernetes cluster set up? fail then answer"
#: HIGH turn + the embedding trigger: the pre-stream embedding 500s once.
EMBED_Q = "How is my Kubernetes cluster set up? embed fail once"
#: LOW turn + the exhaustion trigger: every streaming request 500s.
EXHAUST_Q = "How do I bake sourdough bread? always fail"

#: The conftest forces BOR_LLM_RETRIES to its default (3) → 4 attempts
#: total; the attempt math in the assertions is fixed by that budget.
MAX_ATTEMPTS = 4


def _retry_status(attempt: int) -> str:
    """The owner-locked A4 copy for *attempt* (1-based) of MAX_ATTEMPTS."""
    return f"Communication interrupted — retrying ({attempt} of {MAX_ATTEMPTS})…"


MOCK_ANSWER_MARKER = "Deterministic mock answer for E2E"
DEFLECT_PHRASE = r"haven't done anything like that"
ERROR_COPY = "The chat model dropped the connection — try again?"

# --------------------------------------------------------------------------
# DB seeding (TRUNCATE-then-seed, cf. test_agent_document_tools.py)
# --------------------------------------------------------------------------


def _seed(db: Session) -> None:
    """The single fixture document (see the module docstring)."""
    md = Document(
        source=SEED_SOURCE,
        path=SEED_PATH,
        full_path=f"/tmp/{SEED_PATH}",
        title="Kubernetes",
        content=KUB_CONTENT,
        content_hash=hashlib.sha256(KUB_CONTENT.encode()).hexdigest(),
        indexed_at=datetime.now(UTC),
    )
    db.add(md)
    db.flush()
    # One chunk carrying the mock's own embedding → genuine token overlap
    # for the grounded questions (the FTS path carries them to HIGH).
    db.add(
        Chunk(
            document_id=md.id,
            position=0,
            content=KUB_CONTENT,
            embedding=embed_text(KUB_CONTENT),
        )
    )


def _reset_db() -> None:
    """Truncate the KB (plus the prompt-shaping tables), then re-seed.

    ``steering_notes`` / ``kb_overview`` are truncated too, so the
    prompts are exactly ``<relevance>`` + ``<documents>`` (+ ``<tools>``
    on HIGH) regardless of leftovers from other suites — byte-stable
    prompts, byte-stable answers.
    """
    with SessionLocal() as db:
        db.execute(
            text("TRUNCATE chunks, documents, query_log, steering_notes, kb_overview")
        )
        db.commit()
        _seed(db)
        db.commit()


def _last_query_log() -> QueryLog:
    with SessionLocal() as db:
        rows = db.scalars(select(QueryLog)).all()
    assert len(rows) == 1, f"expected exactly one query_log row, got {len(rows)}"
    return rows[0]


# --------------------------------------------------------------------------
# Page hooks (the #send-status recorder + SSE capture, the phase-37
# pattern from test_agent_document_tools.py)
# --------------------------------------------------------------------------

#: Records every value #send-status takes during the turn (a
#: MutationObserver on the element), so the in-flight status sequence —
#: including the transient phase-67 "retrying" states — is captured
#: deterministically (no polling race).
STATUS_RECORDER = """
() => {
  if (window.__statusesInstalled) return;
  window.__statusesInstalled = true;
  window.__statuses = [];
  const el = document.querySelector('#send-status');
  if (!el) return;
  const rec = (v) => {
    const l = window.__statuses;
    if (!l.length || l[l.length - 1] !== v) l.push(v);
  };
  rec(el.textContent);
  new MutationObserver(() => rec(el.textContent)).observe(el, {
    childList: true,
    subtree: true,
  });
}
"""

#: Captures the raw SSE ``data:`` payloads of the /api/chat stream
#: (a response clone read in the background) — wire-level assertions
#: for the ``retry`` frames, independent of the UI rendering.
SSE_HOOK = """
() => {
  if (window.__sseInstalled) return;
  window.__sseInstalled = true;
  window.__sseFrames = [];
  const origFetch = window.fetch;
  window.fetch = async function (...args) {
    const res = await origFetch.apply(this, args);
    try {
      const url = typeof args[0] === 'string' ? args[0] : args[0].url;
      if (url.includes('/api/chat')) {
        res.clone().text().then((bodyText) => {
          for (const block of bodyText.split('\\n\\n')) {
            const line = block.trim();
            if (line.startsWith('data: ')) {
              window.__sseFrames.push(line.slice(6));
            }
          }
        });
      }
    } catch (e) { /* non-clonable responses: ignored */ }
    return res;
  };
}
"""


def _install_page_hooks(page: Page) -> None:
    """Install both hooks on the loaded page (post-goto, pre-submit).

    The fetch wrapper only needs to be in place before the turn's
    ``fetch("/api/chat")`` call; the observer needs the rendered
    ``#send-status``. (``add_init_script`` would not do — it binds to
    the NEXT navigation, and the story page is navigated exactly once.)
    """
    page.evaluate(SSE_HOOK)
    page.evaluate(STATUS_RECORDER)


def _frames(page: Page, terminal: str = "done") -> list[dict]:
    """The captured SSE frames, once the *terminal* frame lands.

    The hook reads ``res.clone().text()`` in a background promise that
    resolves right after the stream closes — poll briefly until the
    terminal (``done``, or ``error`` for the exhaustion test) lands.
    """
    deadline = time.monotonic() + 30.0
    while True:
        raw = page.evaluate("() => window.__sseFrames || []")
        parsed = [json.loads(line) for line in raw if line]
        if any(f.get("type") == terminal for f in parsed):
            return parsed
        if time.monotonic() > deadline:
            raise AssertionError(
                f"SSE hook captured no `{terminal}` frame (frames so far: "
                f"{len(parsed)}) — hook install failed?"
            )
        time.sleep(0.05)


def _retry_frames(frames: list[dict]) -> list[dict]:
    return [f for f in frames if f.get("type") == "retry"]


def _assert_retries_before_first_delta(frames: list[dict], retries: list[dict]) -> None:
    """The wire contract (locked A2): every retry frame precedes the
    first answer delta — a retry can only restart a request that never
    streamed a frame."""
    assert retries, "no retry frames on the wire"
    first_delta = next(i for i, f in enumerate(frames) if f.get("type") == "delta")
    assert all(
        i < first_delta for i, f in enumerate(frames) if f.get("type") == "retry"
    )


def _assert_no_error_frames(frames: list[dict]) -> None:
    assert not [f for f in frames if f.get("type") == "error"]


def _submit(page: Page, question: str) -> None:
    page.fill("#message-input", question)
    page.click("#send-btn")
    # The user bubble lands synchronously with the submit handler.
    expect(page.locator(".msg.user .bubble").last).to_contain_text(question)


def _wait_settled(page: Page) -> None:
    """The turn is complete: answer text in the bubble, button recovered.

    Phase 48: the label assertion carries the settle wait with an
    explicit timeout — the in-flight button is the enabled Stop control
    (never disabled), so ``to_be_enabled`` no longer blocks until the
    turn settles, and Playwright expect's default (5s) does not inherit
    the page default."""
    expect(page.locator(".msg.brain .bubble").last).not_to_have_text("", timeout=30_000)
    expect(page.locator("#send-btn")).to_be_enabled(timeout=30_000)
    expect(page.locator("#send-label")).to_have_text("Send", timeout=30_000)


def _assert_no_error_banner(page: Page) -> None:
    """A retried turn settles through the normal done path — never the
    red role=alert error banner (the KB-offline banner is a separate,
    health-driven state the db_ready fixture keeps away)."""
    banner = page.locator("#kb-banner")
    expect(banner).to_be_hidden()
    expect(banner).not_to_have_attribute("role", "alert")
    expect(banner).not_to_have_class(re.compile(r"is-error"))


# --------------------------------------------------------------------------
# 1. Dead-then-recovered, DEFLECTED path (LOW turn): the status line
#    shows the live "retrying" copy and the answer still completes
# --------------------------------------------------------------------------


def test_dead_then_recovered_deflected(
    page: Page, app_url: str, mock_llm: int, db_ready: None
) -> None:
    _reset_db()
    page.set_default_timeout(30_000)
    login(page, app_url, next="/")
    _install_page_hooks(page)

    _submit(page, DEFLECT_Q)
    _wait_settled(page)

    # The live status (owner-locked A4 copy) was recorded for BOTH
    # restarts: attempt 2 (after the original attempt died) and attempt
    # 3 (after the first retry died) — attempt 4 never needed to start.
    statuses = page.evaluate("() => window.__statuses")
    assert _retry_status(2) in statuses, statuses
    assert _retry_status(3) in statuses, statuses

    # Wire: exactly the two retry frames (attempt = the attempt about to
    # be tried, 1-based; max_attempts = the forced-default budget of 4),
    # both ahead of the first delta, and no error frame anywhere.
    frames = _frames(page)
    retries = _retry_frames(frames)
    assert retries == [
        {"type": "retry", "attempt": 2, "max_attempts": MAX_ATTEMPTS},
        {"type": "retry", "attempt": 3, "max_attempts": MAX_ATTEMPTS},
    ], retries
    _assert_retries_before_first_delta(frames, retries)
    _assert_no_error_frames(frames)
    done = next(f for f in frames if f.get("type") == "done")
    assert done["deflected"] is True

    # The deflected answer settled normally — no error banner.
    last = page.locator(".msg.brain").last
    expect(last).to_have_class(re.compile(r"is-deflected"))
    expect(last.locator(".bubble")).to_contain_text(
        re.compile(DEFLECT_PHRASE, re.IGNORECASE)
    )
    _assert_no_error_banner(page)

    row = _last_query_log()
    assert row.question == DEFLECT_Q
    assert row.deflected is True


# --------------------------------------------------------------------------
# 2. Dead-then-recovered, GROUNDED path (HIGH turn): the agent round
#    retried and the answer completes with its sources
# --------------------------------------------------------------------------


def test_dead_then_recovered_grounded(
    page: Page, app_url: str, mock_llm: int, db_ready: None
) -> None:
    _reset_db()
    page.set_default_timeout(30_000)
    login(page, app_url, next="/")
    _install_page_hooks(page)

    _submit(page, GROUNDED_Q)
    _wait_settled(page)

    # Same status sequence as the deflected path — the per-round retry
    # (agent loop, task 03) surfaces through the same status line.
    statuses = page.evaluate("() => window.__statuses")
    assert _retry_status(2) in statuses, statuses
    assert _retry_status(3) in statuses, statuses

    frames = _frames(page)
    retries = _retry_frames(frames)
    assert retries == [
        {"type": "retry", "attempt": 2, "max_attempts": MAX_ATTEMPTS},
        {"type": "retry", "attempt": 3, "max_attempts": MAX_ATTEMPTS},
    ], retries
    _assert_retries_before_first_delta(frames, retries)
    _assert_no_error_frames(frames)
    done = next(f for f in frames if f.get("type") == "done")
    assert done["deflected"] is False
    # Phase 119 (LOCKED A1): the grounded turn read NOTHING, so
    # done.sources is empty (the suggested seed doc never chips — the
    # retired phase-118 A4 union is gone); the durable record below
    # still carries it (LOCKED A3, untouched).
    assert done["sources"] == [], done["sources"]

    # The grounded answer completed (no chips on a zero-read turn —
    # phase 119 A1) — the agent round retried and the turn is intact.
    bubble = page.locator(".msg.brain .bubble").last
    expect(bubble).to_contain_text(GROUNDED_Q)
    expect(bubble).to_contain_text(MOCK_ANSWER_MARKER)
    expect(page.locator(".msg.brain .source-chip")).to_have_count(0)
    _assert_no_error_banner(page)

    row = _last_query_log()
    assert row.question == GROUNDED_Q
    assert row.deflected is False
    assert row.sources == SEED_SP


# --------------------------------------------------------------------------
# 3. Embedding retry: the pre-stream embedding loop is visible to the
#    UI (a retry status before any answer) and the turn completes
# --------------------------------------------------------------------------


def test_embedding_retry_completes(
    page: Page, app_url: str, mock_llm: int, db_ready: None
) -> None:
    _reset_db()
    page.set_default_timeout(30_000)
    login(page, app_url, next="/")
    _install_page_hooks(page)

    _submit(page, EMBED_Q)
    _wait_settled(page)

    # The embedding step runs BEFORE the honesty gate and the answer
    # stream, so its single retry is the ONLY retry frame of the turn —
    # and the UI saw it as the live status (no answer frame had landed).
    statuses = page.evaluate("() => window.__statuses")
    assert _retry_status(2) in statuses, statuses

    frames = _frames(page)
    retries = _retry_frames(frames)
    assert retries == [
        {"type": "retry", "attempt": 2, "max_attempts": MAX_ATTEMPTS},
    ], retries
    _assert_retries_before_first_delta(frames, retries)
    _assert_no_error_frames(frames)
    done = next(f for f in frames if f.get("type") == "done")
    assert done["deflected"] is False

    # The turn completed normally with the grounded answer (zero chips
    # — the turn read nothing, so the chip row is empty under phase
    # 119, LOCKED A1; the retired phase-118 A4 union is gone).
    bubble = page.locator(".msg.brain .bubble").last
    expect(bubble).to_contain_text(MOCK_ANSWER_MARKER)
    expect(page.locator(".msg.brain .source-chip")).to_have_count(0)
    _assert_no_error_banner(page)


# --------------------------------------------------------------------------
# 4. Exhaustion: a dead endpoint burns the whole budget, then the
#    EXISTING terminal error banner lands and the composer recovers
# --------------------------------------------------------------------------


def test_exhaustion_lands_on_the_error_banner(
    page: Page, app_url: str, mock_llm: int, db_ready: None
) -> None:
    _reset_db()
    page.set_default_timeout(30_000)
    login(page, app_url, next="/")
    _install_page_hooks(page)

    _submit(page, EXHAUST_Q)

    # After the 4th dead attempt the turn dies: the existing terminal
    # error banner (role=alert) with the existing copy, and the send
    # button re-enabled (the banner path settles the state machine).
    expect(page.locator("#kb-banner")).to_have_attribute(
        "role", "alert", timeout=60_000
    )
    expect(page.locator("#kb-banner")).to_contain_text(ERROR_COPY)
    expect(page.locator("#send-btn")).to_be_enabled(timeout=30_000)
    expect(page.locator("#send-label")).to_have_text("Send", timeout=30_000)

    # The live status climbed the whole budget: the LAST retrying status
    # is the highest attempt — "(4 of 4)…" (no attempt 5 exists).
    statuses = page.evaluate("() => window.__statuses")
    retry_statuses = [s for s in statuses if "retrying" in s]
    assert retry_statuses, statuses
    assert retry_statuses[-1] == _retry_status(MAX_ATTEMPTS), statuses

    # Wire: the three retry frames (attempts 2, 3, 4 of 4), then the
    # terminal error frame as the LAST event — no done, no delta.
    frames = _frames(page, terminal="error")
    retries = _retry_frames(frames)
    assert retries == [
        {"type": "retry", "attempt": a, "max_attempts": MAX_ATTEMPTS}
        for a in (2, 3, 4)
    ], retries
    assert frames[-1]["type"] == "error"
    assert ERROR_COPY in frames[-1]["detail"]
    assert not [f for f in frames if f.get("type") == "done"]
    assert not [f for f in frames if f.get("type") == "delta"]

    # No answer bubble was ever rendered (no frame ever streamed a
    # token) — the user bubble is the only message in the DOM.
    expect(page.locator("#messages > .msg.brain")).to_have_count(0)
    expect(page.locator(".msg.user .bubble")).to_have_count(1)