"""Tests for the LLM brewing advice: the prompt, the storage and the display."""

from __future__ import annotations

import json
from contextlib import contextmanager
from datetime import date

import pytest

import brew_advice
from conftest import seed_readings


# ------------------------------------------------------------ the prompt #

def test_the_prompt_gives_the_model_the_brew_and_its_readings():
    """The model needs the name, the OG and every reading."""
    run = {
        "canonical_name": "Nocturna Christmas beer",
        "og_decimal": 1.042,
        "tap_number": 3,
        "notes": "dark malt, 19C",
    }
    reading = {"date": "2026-01-10", "sg_decimal": 1.022,
               "point_scale": "1022 points", "comment": "no change since day 7",
               "final": False}
    history = [
        {"date": "2026-01-01", "sg_decimal": 1.042, "point_scale": "1042 points",
         "comment": "", "final": False},
        reading,
    ]

    prompt = brew_advice.build_prompt(run, reading, history)

    assert "Nocturna Christmas beer" in prompt
    assert "1.042" in prompt
    assert "Fermenter tap: 3" in prompt
    assert "dark malt" in prompt
    # Both readings, oldest first.
    assert "2026-01-01" in prompt
    assert "2026-01-10" in prompt
    assert "no change since day 7" in prompt
    assert "1.022" in prompt


def test_the_prompt_tells_the_model_not_to_call_a_reading_impossible():
    """A reading below 1.000 is a mis-entry, but the run may still be real.

    This matters: the brewer's own run 12 was a genuine long fermentation
    that the app flagged as impossible.  The model must not repeat that
    mistake - it should point at the odd reading and keep talking about
    the brew.
    """
    assert "Never say a reading is impossible" in brew_advice.SYSTEM_PROMPT
    assert "still be real" in brew_advice.SYSTEM_PROMPT


def test_the_prompt_names_the_reading_to_advise_about():
    """The reading being advised about must be NAMED.

    The brewer may be correcting an OLDER reading, so "the most recent
    reading" is the wrong one - and the advice would be about the wrong
    number.  The reading is marked in the list and named in the
    instruction.
    """
    run = {"canonical_name": "Ale"}
    older = {"_id": "old", "date": "2026-01-01", "sg_decimal": 1.042,
             "point_scale": "1042 points", "comment": "", "final": False}
    newer = {"_id": "new", "date": "2026-01-10", "sg_decimal": 1.030,
             "point_scale": "1030 points", "comment": "", "final": False}

    prompt = brew_advice.build_prompt(run, older, [older, newer])

    # The older one is the subject.
    assert "THIS IS THE READING TO ADVISE ON" in prompt
    # And it is named, with its date and gravity.
    assert "2026-01-01" in prompt
    assert "1.042" in prompt
    # And NOT the newer one.
    assert "1.03" in prompt  # it is in the history, which is right
    assert prompt.count("THIS IS THE READING TO ADVISE ON") == 1


def test_the_prompt_says_when_a_reading_has_been_corrected():
    """A corrected reading may differ from what it said before."""
    run = {"canonical_name": "Ale"}
    reading = {"_id": "r1", "date": "2026-01-01", "sg_decimal": 1.012,
               "point_scale": "1012 points", "comment": "", "final": False}

    plain = brew_advice.build_prompt(run, reading, [reading])
    assert "just corrected" not in plain

    corrected = brew_advice.build_prompt(run, reading, [reading], corrected=True)
    assert "just corrected" in corrected
    assert "may differ" in corrected


def test_the_prompt_marks_the_final_reading():
    run = {"canonical_name": "Ale"}
    reading = {"date": "2026-01-20", "sg_decimal": 1.010, "point_scale": "1010 points",
               "comment": "", "final": True}
    prompt = brew_advice.build_prompt(run, reading, [reading])
    assert "FINAL reading" in prompt


# ---------------------------------------------------------- the LLM call #

def test_a_successful_call_returns_the_text(monkeypatch):
    """A normal reply comes back as the advice."""
    captured = {}

    def fake_urlopen(request, timeout=None):
        captured["url"] = request.full_url
        captured["body"] = json.loads(request.data.decode())

        class Response:
            def read(self):
                return json.dumps({
                    "choices": [{"message": {"content": "  Leave it alone, it is still fermenting.  "}}]
                }).encode()

            def __enter__(self):
                return self

            def __exit__(self, *args):
                return False

        return Response()

    monkeypatch.setattr(brew_advice.urllib.request, "urlopen", fake_urlopen)

    ok, text = brew_advice.generate_advice(
        {"canonical_name": "Ale"},
        {"date": "2026-01-01", "sg_decimal": 1.042, "point_scale": "1042 points",
         "comment": "", "final": False},
        [{"date": "2026-01-01", "sg_decimal": 1.042, "point_scale": "1042 points",
          "comment": "", "final": False}],
        model="glm-5.3:cloud",
    )

    assert ok is True
    assert text == "Leave it alone, it is still fermenting."
    assert captured["url"].endswith("/v1/chat/completions")
    assert captured["body"]["model"] == "glm-5.3:cloud"


def test_an_unreachable_model_does_not_raise(monkeypatch):
    """A failure is recorded, not raised.

    The reading has to be saved either way, and a silent failure would be
    indistinguishable from "the advice is still being generated".
    """
    def boom(request, timeout=None):
        raise brew_advice.urllib.error.URLError("connection refused")

    monkeypatch.setattr(brew_advice.urllib.request, "urlopen", boom)

    ok, text = brew_advice.generate_advice(
        {"canonical_name": "Ale"},
        {"date": "2026-01-01", "sg_decimal": 1.042, "point_scale": "1042 points",
         "comment": "", "final": False},
        [],
    )

    assert ok is False
    assert "could not be generated" in text


def test_an_empty_reply_is_a_failure(monkeypatch):
    """A model that returns nothing has not given advice."""

    class Response:
        def read(self):
            return json.dumps({"choices": [{"message": {"content": "   "}}]}).encode()

        def __enter__(self):
            return self

        def __exit__(self, *args):
            return False

    monkeypatch.setattr(brew_advice.urllib.request, "urlopen",
                        lambda request, timeout=None: Response())

    ok, text = brew_advice.generate_advice({"canonical_name": "Ale"},
                                            {"date": "2026-01-01"}, [])
    assert ok is False
    assert "could not be generated" in text


def test_the_token_budget_leaves_room_for_the_reasoning(monkeypatch):
    """The reasoning models emit their thinking first, out of the same budget.

    At 500 tokens the reasoning used the whole allowance and the reply
    came back EMPTY - which looks like a broken model rather than a
    budget problem.  The budget has to cover the reasoning AND the advice.
    """
    captured = {}

    def fake_urlopen(request, timeout=None):
        captured["body"] = json.loads(request.data.decode())

        class Response:
            def read(self):
                return json.dumps({
                    "choices": [{"message": {"content": "Rouse the yeast."}}]
                }).encode()

            def __enter__(self):
                return self

            def __exit__(self, *args):
                return False

        return Response()

    monkeypatch.setattr(brew_advice.urllib.request, "urlopen", fake_urlopen)

    brew_advice.generate_advice({"canonical_name": "Ale"},
                                 {"date": "2026-01-01"}, [])

    assert captured["body"]["max_tokens"] >= 2000


def test_the_advice_is_truncated():
    """A runaway reply must not fill the reading document."""
    long_text = "x" * 5000

    class Response:
        def read(self):
            return json.dumps({"choices": [{"message": {"content": long_text}}]}).encode()

        def __enter__(self):
            return self

        def __exit__(self, *args):
            return False

    import brew_advice as ba
    original = ba.urllib.request.urlopen
    ba.urllib.request.urlopen = lambda request, timeout=None: Response()
    try:
        ok, text = ba.generate_advice({"canonical_name": "Ale"},
                                       {"date": "2026-01-01"}, [])
    finally:
        ba.urllib.request.urlopen = original

    assert ok is True
    assert len(text) <= ba.MAX_ADVICE_CHARS


# ------------------------------------------------------------- storage #

def test_the_advice_is_stored_in_its_own_field(repo):
    """The brewer's comment is never overwritten."""
    seed_readings(repo, [("1", "Ale", "1042", "2026-01-01", False, "my own comment")])

    doc = repo.readings.find_one({"beer_run_id": "1"})
    repo.set_reading_advice(str(doc["_id"]), "The advice", ok=True)

    updated = repo.readings.find_one({"beer_run_id": "1"})
    assert updated["advice"] == "The advice"
    assert updated["advice_ok"] is True
    # The brewer's own comment is untouched.
    assert updated["comment"] == "my own comment"


def test_editing_a_reading_clears_its_stale_advice(repo):
    """The advice was written for the gravity that was there before.

    If the reading is edited, that advice no longer describes it, so it
    is cleared and a fresh one is generated.  The brewer's own comment is
    never cleared.
    """
    seed_readings(repo, [("1", "Ale", "1042", "2026-01-01", False, "my comment")])

    doc = repo.readings.find_one({"beer_run_id": "1"})
    repo.set_reading_advice(str(doc["_id"]), "THE ADVICE", True)

    # Edit the reading.
    repo.upsert_reading(beer_run_id="1", beer_type="Ale", sg=1030,
                         reading_date="2026-01-01", final_reading=False,
                         comment="my comment")

    after = repo.readings.find_one({"beer_run_id": "1"})
    assert after.get("advice") is None, "the stale advice was kept"
    assert after["comment"] == "my comment", "the brewer's comment was touched"
    assert after["sg"] == "1030"


def test_the_advice_is_stored_on_a_reading_with_a_string_id(repo):
    """The original app's readings have 24-character STRING ids.

    This is the shape every existing reading in the live database has -
    the ids were generated by the old app as random characters, not by
    Mongo.  A helper that only accepted an ObjectId would have matched
    nothing, and the advice would silently never be stored.

    The mongomock fixture generates ObjectIds, so this has to be
    constructed explicitly or the bug is invisible in the tests.
    """
    repo.readings.insert_one({
        "_id": "l78ZidBJ3QaYn98tvB88x4uM",
        "beer_run_id": "1",
        "beer_type": "Ale",
        "sg": "1042",
        "date": "2026-01-01",
        "final_reading": "False",
        "comment": "First ever try",
    })

    modified = repo.set_reading_advice("l78ZidBJ3QaYn98tvB88x4uM",
                                        "THE ADVICE", True)
    assert modified == 1, "the advice was not stored on a string-id reading"

    after = repo.readings.find_one({"_id": "l78ZidBJ3QaYn98tvB88x4uM"})
    assert after["advice"] == "THE ADVICE"
    assert after["comment"] == "First ever try"


def test_the_advice_is_stored_on_a_reading_with_an_object_id(repo):
    """The other shape: a reading written by Mongo itself."""
    seed_readings(repo, [("1", "Ale", "1042", "2026-01-01", False, "a comment")])
    doc = repo.readings.find_one({"beer_run_id": "1"})

    modified = repo.set_reading_advice(str(doc["_id"]), "THE ADVICE", True)
    assert modified == 1

    after = repo.readings.find_one({"beer_run_id": "1"})
    assert after["advice"] == "THE ADVICE"


def test_writing_the_advice_does_not_leak_a_client_per_reading():
    """A MongoClient spawns three monitor threads and pymongo does not
    reap them on close() - they go only when the client is collected.

    So building a client per advice write accumulated three threads and a
    connection pool for every reading recorded.  The advice writer shares
    one client for the life of the process instead.
    """
    import inspect

    from views import brews as brews_module

    # The writer must NOT build a repository of its own - it has to use
    # the shared one.  A MongoClient spawns three monitor threads and
    # pymongo does not reap them on close(), so a client per advice write
    # accumulated three threads and a connection pool for every reading
    # recorded.
    source = inspect.getsource(brews_module._start_advice)

    assert "BeerRepository()" not in source, (
        "the advice writer builds its own repository - that leaks a Mongo "
        "client (three monitor threads) per reading"
    )
    assert "get_shared_repository" in source, (
        "the advice writer must use the shared repository"
    )


@contextmanager
def _app_with_repo(repo):
    """An application context whose repository is *repo*.

    The view reads the repository from ``app.extensions``, so pointing
    that at a fixture is enough to drive the view's code directly.
    """
    from app_factory import create_app

    app = create_app({
        "TESTING": True,
        "WTF_CSRF_ENABLED": False,
        "SECRET_KEY": "test-secret",
        "MONGO_CLIENT": repo.client,
    })
    # The advice must be generated even though this is a test app.
    app.config["TESTING"] = False

    original = app.extensions["beer_repo"]
    app.extensions["beer_repo"] = lambda: repo
    with app.app_context():
        try:
            yield app
        finally:
            app.extensions["beer_repo"] = original


def test_the_advice_is_about_the_reading_that_was_saved():
    """Editing an OLDER reading must not generate advice about the newest.

    The advice is written against a specific reading, so the reading being
    saved has to be the one the advice is about.
    """
    import time

    import mongomock
    from mongo.repository import BeerRepository
    from views import brews as brews_module
    from views.brews import _start_advice

    captured = {}

    def fake_generate(run, reading, history, writer=None, corrected=False):
        captured["reading"] = reading
        captured["history"] = history
        captured["corrected"] = corrected
        return True, "THE ADVICE"

    original = brews_module.brew_advice.generate_advice_in_background
    brews_module.brew_advice.generate_advice_in_background = fake_generate
    try:
        # Two readings; the OLDER one is the one being saved.
        repo = BeerRepository(client=mongomock.MongoClient())
        old_id = repo.upsert_reading(beer_run_id="1", beer_type="Ale", sg=1042,
                                     reading_date="2026-01-01", final_reading=False,
                                     comment="first")
        repo.upsert_reading(beer_run_id="1", beer_type="Ale", sg=1030,
                            reading_date="2026-01-10", final_reading=False,
                            comment="second")

        # The advice is only generated when it is enabled, and it is off
        # in testing.
        with _app_with_repo(repo):
            _start_advice("1", old_id)
            for _ in range(40):
                time.sleep(0.05)
                if captured:
                    break
    finally:
        brews_module.brew_advice.generate_advice_in_background = original

    assert captured, "the advice was never generated"
    assert captured["reading"]["_id"] == old_id
    assert captured["reading"]["sg"] == 1042, (
        "the advice was generated about the wrong reading"
    )


def test_the_shared_repository_is_built_only_once():
    """Concurrent advice threads must not each build their own client.

    An unsynchronised check-then-set on a module global let eight threads
    on a cold process each build their own repository - so the fix
    reintroduced the very leak it was meant to remove, just bounded by a
    race instead of by the number of readings.
    """
    import threading

    import mongomock
    import mongo.repository as R

    original_shared = R._shared_repository
    built = []
    original_init = R.BeerRepository.__init__

    def counting_init(self, *args, **kwargs):
        built.append(1)
        original_init(self, *args, **kwargs)

    R._shared_repository = None
    R.BeerRepository.__init__ = counting_init
    original_build = R._build_client
    R._build_client = lambda: mongomock.MongoClient()
    try:
        instances = []
        barrier = threading.Barrier(8)

        def go():
            barrier.wait()          # release all eight at once
            instances.append(id(R.get_shared_repository()))

        threads = [threading.Thread(target=go) for _ in range(8)]
        for t in threads:
            t.start()
        for t in threads:
            t.join()
    finally:
        R._shared_repository = original_shared
        R.BeerRepository.__init__ = original_init
        R._build_client = original_build

    assert len(built) == 1, f"built {len(built)} repositories, expected 1"
    assert len(set(instances)) == 1, "the threads got different repositories"


def test_the_reading_id_cannot_be_used_to_inject_a_query(repo):
    """The reading id is coerced before it reaches Mongo.

    Every value that reaches a Mongo query is coerced first, because a
    caller passing a dict would have it interpreted as a query operator
    rather than a value - the classic NoSQL injection route.  A reading
    id that is not a plain ObjectId or string must match nothing.
    """
    seed_readings(repo, [
        ("1", "Ale", "1042", "2026-01-01", False, ""),
        ("2", "Ale", "1030", "2026-01-01", False, ""),
    ])

    for hostile in [{"$ne": None}, {"$gt": ""}, ["a"], 123, None,
                    "not-an-objectid", ""]:
        modified = repo.set_reading_advice(hostile, "INJECTED", True)
        assert modified == 0, f"{hostile!r} matched something"

    # The helper itself must return something that is safe to put in a
    # query - an empty list matches nothing.  Returning None would raise
    # "$in needs an array" if it were ever used without a guard.
    from mongo.repository import _as_doc_id

    for hostile in [{"$ne": None}, {"$gt": ""}, ["a"], 123, None, ""]:
        assert _as_doc_id(hostile) == [], f"{hostile!r} produced a usable id"

    # And no document was touched.
    for doc in repo.readings.find({}):
        assert doc.get("advice") is None


def test_a_failed_generation_is_stored_as_a_failure(repo):
    """The note says it could not be generated, and is flagged as such."""
    seed_readings(repo, [("1", "Ale", "1042", "2026-01-01", False, "")])

    doc = repo.readings.find_one({"beer_run_id": "1"})
    repo.set_reading_advice(str(doc["_id"]), "Advice could not be generated.", ok=False)

    updated = repo.readings.find_one({"beer_run_id": "1"})
    assert updated["advice_ok"] is False


def test_the_latest_advice_comes_from_the_newest_reading_with_one():
    """The advice for the newest reading wins.

    The advice is generated in the background, so the newest reading may
    not have one yet - in which case the newest that does is used.
    """
    from brewing import Run

    run = Run.from_docs("1", [
        {"_id": "a", "beer_run_id": "1", "sg": "1042", "date": "2026-01-01",
         "final_reading": "False", "comment": "", "advice": "first advice"},
        {"_id": "b", "beer_run_id": "1", "sg": "1030", "date": "2026-01-05",
         "final_reading": "False", "comment": "", "advice": "second advice"},
        {"_id": "c", "beer_run_id": "1", "sg": "1020", "date": "2026-01-10",
         "final_reading": "False", "comment": "", "advice": ""},
    ])

    assert run.latest_advice() == "second advice"
    assert run.latest_advice_ok() is True


# ------------------------------------------------------------- the pages #

def test_recording_a_reading_saves_it_even_when_the_model_is_down(client, repo):
    """The model being down must never stop a reading being saved."""
    repo.users.insert_one({"username": "beer", "password": "beer_pass"})
    client.post("/login", data={"username": "beer", "password": "beer_pass"},
                follow_redirects=True)

    response = client.post("/brews", data={
        "beer_run_id": "99",
        "beer_run_type": "Test ale",
        "Date": "2026-01-01",
        "sg": "1042",
        "comment": "a comment",
    }, follow_redirects=True)

    assert response.status_code == 200
    assert repo.readings.count_documents({"beer_run_id": "99"}) == 1


def test_the_advice_is_shown_on_the_brewing_page(client, repo):
    """The advice appears next to the comment, clearly labelled."""
    repo.users.insert_one({"username": "beer", "password": "beer_pass"})
    client.post("/login", data={"username": "beer", "password": "beer_pass"},
                follow_redirects=True)

    seed_readings(repo, [("1", "Ale", "1042", "2026-01-01", False, "my comment")])
    doc = repo.readings.find_one({"beer_run_id": "1"})
    repo.set_reading_advice(str(doc["_id"]), "Rouse the yeast and wait.", ok=True)

    response = client.get("/brews")
    body = response.get_data(as_text=True)

    assert "Rouse the yeast and wait." in body
    # The brewer's own comment is still there.
    assert "my comment" in body
    # And it is labelled as advice, so the two are not confused.
    assert "Brewing advice" in body


def test_the_advice_is_shown_on_the_active_beers_page(client, repo):
    """The active page is where the brewer looks during a fermentation."""
    repo.users.insert_one({"username": "beer", "password": "beer_pass"})
    client.post("/login", data={"username": "beer", "password": "beer_pass"},
                follow_redirects=True)

    seed_readings(repo, [("1", "Ale", "1042", "2026-01-01", False, "my comment")])
    doc = repo.readings.find_one({"beer_run_id": "1"})
    repo.set_reading_advice(str(doc["_id"]), "Warm it to 21C and wait.", ok=True)

    response = client.get("/active")
    body = response.get_data(as_text=True)

    assert "Warm it to 21C and wait." in body
    assert "Brewing advice" in body


def test_a_failed_advice_is_marked_as_such(client, repo):
    """A generation failure reads differently from real advice."""
    repo.users.insert_one({"username": "beer", "password": "beer_pass"})
    client.post("/login", data={"username": "beer", "password": "beer_pass"},
                follow_redirects=True)

    seed_readings(repo, [("1", "Ale", "1042", "2026-01-01", False, "")])
    doc = repo.readings.find_one({"beer_run_id": "1"})
    repo.set_reading_advice(str(doc["_id"]), "Advice could not be generated.",
                             ok=False)

    response = client.get("/brews")
    body = response.get_data(as_text=True)
    assert "advice--failed" in body


def test_advice_is_not_generated_in_tests(client, repo):
    """The suite must never reach out to a real model."""
    from views.brews import advice_enabled

    with client.application.app_context():
        assert advice_enabled() is False