"""Backend-only rewrite API contract."""

from __future__ import annotations

import os
import importlib

os.environ.setdefault("LANGUAGE_TOOL_ENABLED", "false")
os.environ.setdefault("LANGUAGE_TOOL_URL", "")
os.environ.setdefault("GRAMMAR_FIX_OUTPUT", "false")
os.environ.setdefault("ENGINE_USE_MINILM_SAFETY", "false")
os.environ.setdefault("ENGINE_LEXICAL_REFINEMENT", "false")
os.environ.setdefault("ENGINE_FORCE_REWRITE", "false")

from fastapi.testclient import TestClient

from app.main import app

main_module = importlib.import_module("app.main")
client = TestClient(app)


def test_rewrite_accepts_text_only(monkeypatch):
    monkeypatch.setattr(main_module, "ENGINE_LEXICAL_REFINEMENT", False)
    monkeypatch.setattr(main_module, "ENGINE_FORCE_REWRITE", False)
    monkeypatch.setattr(main_module, "ENGINE_PARAPHRASE", False)
    response = client.post(
        "/v1/rewrite",
        json={"text": "Ram went to school yesterday happily."},
    )
    assert response.status_code == 200
    body = response.json()
    assert body["rewrite"] == "Yesterday, Ram happily went to school."
    assert body["sentences"][0]["status"] == "rewritten"
    assert body["sentences"][0]["template_id"]
    assert isinstance(body["sentences"][0]["confidence"], float)
    assert body["mapping"]
    assert body["stats"]["batches"] == 1
    assert "tone" not in body["meta"]
    assert "strength" not in body["meta"]
    assert "ml_polish" not in body["meta"]


def test_legacy_ui_controls_are_ignored(monkeypatch):
    monkeypatch.setattr(main_module, "ENGINE_LEXICAL_REFINEMENT", False)
    monkeypatch.setattr(main_module, "ENGINE_FORCE_REWRITE", False)
    monkeypatch.setattr(main_module, "ENGINE_PARAPHRASE", False)
    response = client.post(
        "/v1/rewrite",
        json={
            "text": "Ram went to school yesterday happily.",
            "tone": "Formal",
            "strength": 2,
            "ml_polish": True,
        },
    )
    assert response.status_code == 200
    # ml_polish still enables lexical when the env stage is off; force stays off.
    assert "Yesterday" in response.json()["rewrite"]
    assert "Ram" in response.json()["rewrite"]


def test_ml_polish_checkbox_boosts_lexical_changes(monkeypatch):
    captured: dict[str, object] = {}
    original = main_module.rewrite_document

    def capture(text: str, **kwargs):
        captured["enabled"] = kwargs["use_lexical_refinement"]
        captured["max_changes"] = kwargs.get("lexical_max_changes")
        captured["polish"] = kwargs.get("lexical_polish")
        return original(text, use_lexical_refinement=False, force_rewrite=False)

    monkeypatch.setattr(main_module, "ENGINE_LEXICAL_REFINEMENT", True)
    monkeypatch.setattr(main_module, "rewrite_document", capture)
    response = client.post(
        "/v1/rewrite",
        json={
            "text": "Ram went to school yesterday happily.",
            "ml_polish": True,
        },
    )
    assert response.status_code == 200
    assert captured["enabled"] is True
    assert captured["max_changes"] is None
    assert captured["polish"] is True
    assert response.json()["meta"]["ml_polish_requested"] is True


def test_ml_polish_changes_output_more_aggressively():
    text = (
        "The manager subsequently assisted several diligent students during "
        "the unusually difficult afternoon workshop."
    )
    plain = client.post("/v1/rewrite", json={"text": text, "ml_polish": False})
    polished = client.post("/v1/rewrite", json={"text": text, "ml_polish": True})
    assert plain.status_code == 200
    assert polished.status_code == 200
    plain_body = plain.json()
    polished_body = polished.json()
    assert plain_body["rewrite"] != polished_body["rewrite"]
    plain_changes = [
        change
        for sentence in plain_body["sentences"]
        for change in sentence["lexical_changes"]
    ]
    polished_changes = [
        change
        for sentence in polished_body["sentences"]
        for change in sentence["lexical_changes"]
    ]
    assert len(polished_changes) > len(plain_changes)


def test_health_reports_rewrite_service():
    response = client.get("/health")
    assert response.status_code == 200
    body = response.json()
    assert body["service"] == "rewrite-api"
    assert body["rewrite_engine"]["mode"] == (
        "structural+paraphrase-primary+phrase+ensure"
    )
    assert body["rewrite_engine"]["paraphrase"]["primary"] is True
    assert body["ui"] == "react"
    assert "ml_polish" not in body


def test_frontend_root_is_served():
    response = client.get("/")
    assert response.status_code == 200
    assert "text/html" in response.headers["content-type"]
    logo = client.get("/zuzu-logo.png")
    assert logo.status_code == 200
    assert logo.headers["content-type"] == "image/png"