"""Regression tests for Stage-A corpus integrity fixes (TaskMaster #30, #31).

These tests document the bugs that were closed in Stage A so they don't
regress quietly. Each test maps to a real bug or constraint:

  1. DB CHECK ``cases_practice_area_check`` rejects the legacy
     ``'appeals_committee'`` value — only domain values (rishuy_uvniya /
     betterment_levy / compensation_197) and ``''`` are allowed.
     (Bug: many ``cases`` rows stored ``'appeals_committee'`` instead of
     the domain.)

  2. DB CHECK ``case_law_internal_chair_check`` and
     ``case_law_internal_district_check`` reject internal_committee rows
     with empty chair_name/district.
     (Bug: 6 records had source_kind='external_upload' but were really
     internal committee decisions; the flip to internal_committee in
     Stage A.2 surfaced the missing chair/district fields.)

  3. DB CHECK ``case_law_external_arar_check`` rejects external_upload
     rows whose case_number starts with ``"ערר"`` or ``"בל\\"מ"`` —
     committee decisions must go through internal_decision_upload, not
     precedent_library_upload.
     (Bug: the legacy upload path stored everything as external_upload,
     including appeal-committee decisions; the citation guard now
     redirects them.)

  4. MCP tool ``precedent_library_upload`` returns an ``_err`` envelope
     when the citation starts with ``"ערר"`` (citation guard, not DB
     constraint — fires before INSERT to surface a helpful error).

These tests connect to the live local Postgres (port 5433) — they do not
mock asyncpg. Run with::

    pytest mcp-server/tests/test_corpus_constraints.py -v

If you don't have ``DATABASE_URL`` set, the tests are skipped.
"""

from __future__ import annotations

import asyncio
import json
import os
from uuid import uuid4

import asyncpg
import pytest


def _dsn() -> str | None:
    return (
        os.environ.get("DATABASE_URL")
        or os.environ.get("LEGAL_AI_DATABASE_URL")
        or "postgresql://legal_ai:od0ASJZFYibOlWK59krLvvETmgqwlXe8@localhost:5433/legal_ai"
    )


@pytest.fixture()
def dsn() -> str:
    d = _dsn()
    if not d:
        pytest.skip("No DATABASE_URL set; skipping live-DB regression tests")
    return d


@pytest.fixture()
def event_loop():
    """Provide a fresh event loop per test so asyncpg doesn't leak across cases."""
    loop = asyncio.new_event_loop()
    try:
        yield loop
    finally:
        loop.close()


def _run(loop, coro):
    return loop.run_until_complete(coro)


# ── 1. cases.practice_area CHECK ─────────────────────────────────────


def test_cases_rejects_appeals_committee_practice_area(dsn: str, event_loop) -> None:
    """``cases.practice_area = 'appeals_committee'`` must violate the CHECK."""

    async def attempt() -> None:
        conn = await asyncpg.connect(dsn)
        try:
            with pytest.raises(asyncpg.exceptions.CheckViolationError):
                await conn.execute(
                    """INSERT INTO cases (id, case_number, title, practice_area)
                       VALUES ($1, $2, $3, $4)""",
                    uuid4(), f"TEST-{uuid4().hex[:8]}", "regression-test",
                    "appeals_committee",
                )
        finally:
            await conn.close()

    _run(event_loop, attempt())


def test_cases_accepts_domain_practice_area(dsn: str, event_loop) -> None:
    """Sanity check: rishuy_uvniya / betterment_levy / compensation_197
    + empty string must be accepted."""

    async def attempt() -> None:
        conn = await asyncpg.connect(dsn)
        try:
            tx = conn.transaction()
            await tx.start()
            try:
                for value in ("rishuy_uvniya", "betterment_levy",
                              "compensation_197", ""):
                    await conn.execute(
                        """INSERT INTO cases (id, case_number, title, practice_area)
                           VALUES ($1, $2, $3, $4)""",
                        uuid4(), f"TEST-{uuid4().hex[:8]}",
                        f"regression-{value or 'empty'}", value,
                    )
            finally:
                await tx.rollback()
        finally:
            await conn.close()

    _run(event_loop, attempt())


# ── 2. case_law internal_committee chair/district CHECK ─────────────


def test_case_law_internal_requires_chair_and_district(dsn: str, event_loop) -> None:
    """``case_law`` rows with ``source_kind='internal_committee'`` must have
    non-empty ``chair_name`` AND ``district``."""

    async def attempt_missing_chair() -> None:
        conn = await asyncpg.connect(dsn)
        try:
            with pytest.raises(asyncpg.exceptions.CheckViolationError):
                await conn.execute(
                    """INSERT INTO case_law (id, case_number, case_name,
                           source_kind, district, chair_name)
                       VALUES ($1, $2, $3, $4, $5, $6)""",
                    uuid4(), f"ערר {uuid4().hex[:6]}",
                    "test internal w/o chair",
                    "internal_committee", "ירושלים", "",
                )
        finally:
            await conn.close()

    async def attempt_missing_district() -> None:
        conn = await asyncpg.connect(dsn)
        try:
            with pytest.raises(asyncpg.exceptions.CheckViolationError):
                await conn.execute(
                    """INSERT INTO case_law (id, case_number, case_name,
                           source_kind, district, chair_name)
                       VALUES ($1, $2, $3, $4, $5, $6)""",
                    uuid4(), f"ערר {uuid4().hex[:6]}",
                    "test internal w/o district",
                    "internal_committee", "", "עו\"ד דפנה תמיר",
                )
        finally:
            await conn.close()

    _run(event_loop, attempt_missing_chair())
    _run(event_loop, attempt_missing_district())


# ── 3. case_law external_upload + ערר citation CHECK ────────────────


def test_case_law_external_upload_rejects_arar_citation(dsn: str, event_loop) -> None:
    """``case_law`` rows with ``source_kind='external_upload'`` cannot have
    a ``case_number`` that starts with ``"ערר"`` or ``"בל\"מ"`` — those
    are committee decisions and must use ``source_kind='internal_committee'``."""

    async def attempt_arar() -> None:
        conn = await asyncpg.connect(dsn)
        try:
            with pytest.raises(asyncpg.exceptions.CheckViolationError):
                await conn.execute(
                    """INSERT INTO case_law (id, case_number, case_name,
                           source_kind)
                       VALUES ($1, $2, $3, $4)""",
                    uuid4(), "ערר 1170/24 חיים נ' ועדה",
                    "test external arar", "external_upload",
                )
        finally:
            await conn.close()

    async def attempt_balam() -> None:
        conn = await asyncpg.connect(dsn)
        try:
            with pytest.raises(asyncpg.exceptions.CheckViolationError):
                await conn.execute(
                    """INSERT INTO case_law (id, case_number, case_name,
                           source_kind)
                       VALUES ($1, $2, $3, $4)""",
                    uuid4(), 'בל"מ 1234/25 פלוני',
                    "test external balam", "external_upload",
                )
        finally:
            await conn.close()

    _run(event_loop, attempt_arar())
    _run(event_loop, attempt_balam())


# ── 4. MCP precedent_library_upload citation guard ──────────────────


def test_mcp_precedent_upload_rejects_arar_citation() -> None:
    """The MCP tool ``precedent_library_upload`` must short-circuit
    citations that start with ``"ערר"`` / ``"בל\"מ"`` and return an
    ``_err`` envelope (a helpful message redirecting to
    ``internal_decision_upload``), without touching the DB."""

    from legal_mcp.tools import precedent_library as tools

    async def call(citation: str) -> dict:
        # file_path won't be touched because the guard fires first.
        return json.loads(
            await tools.precedent_library_upload(
                file_path="/nonexistent",
                citation=citation,
            )
        )

    loop = asyncio.new_event_loop()
    try:
        for citation in (
            "ערר 1170/24 חיים נ' ועדה",
            'בל"מ 1234/25 פלוני',
            "ARAR 8126-25 ב. קרן-נכסים",
        ):
            result = loop.run_until_complete(call(citation))
            assert "error" in result, (
                f"expected guard to reject {citation!r}, got {result!r}"
            )
            # The error message should mention internal_decision_upload so
            # the caller knows the alternative path.
            assert "internal_decision_upload" in result["error"], (
                f"error message should redirect to internal_decision_upload, "
                f"got {result['error']!r}"
            )
    finally:
        loop.close()


def test_practice_area_module_invariants() -> None:
    """Quick guard that the ``practice_area`` service module exposes the
    helpers tools and tests depend on, and that derivation is consistent
    with the case-number convention (1xxx/8xxx/9xxx)."""

    from legal_mcp.services import practice_area as pa

    # Domain mapping is consistent with the case-number prefix convention.
    assert pa.derive_domain_practice_area("1170") == "rishuy_uvniya"
    assert pa.derive_domain_practice_area("8126/25") == "betterment_levy"
    assert pa.derive_domain_practice_area("9001") == "compensation_197"
    assert pa.derive_domain_practice_area("ARAR-25-8126") == "betterment_levy"
    # Unparseable input → empty (caller decides fallback).
    assert pa.derive_domain_practice_area("foo") == ""
    assert pa.derive_domain_practice_area("") == ""

    # Empty practice_area is valid (DB allows it as 'unclassified').
    pa.validate("", "unknown")
    pa.validate("rishuy_uvniya", "building_permit")
    pa.validate("betterment_levy", "betterment_levy")

    # appeals_committee (axis A) is still recognised for backward-compat.
    pa.validate("appeals_committee", "building_permit")

    # is_override returns False when subtype matches derivation.
    assert pa.is_override("1170", "rishuy_uvniya", "building_permit") is False
    assert pa.is_override("8126", "betterment_levy", "betterment_levy") is False