"""Tests for import service: fall_id generation and schema validation.

Unit tests that do NOT require a database connection.
DB-dependent tests (duplicate detection, preview, confirm) are marked
with pytest.mark.skip and documented for future integration testing.
"""

from datetime import date
from unittest.mock import MagicMock, patch

import pytest

from app.schemas.import_schemas import ImportPreview, ImportResult, ImportRow
from app.services.csv_parser import ParsedCase
from app.services.import_service import (
    check_duplicate,
    confirm_import,
    generate_fall_id,
    generate_random_suffix,
    preview_import,
)


# ── Helpers ──────────────────────────────────────────────────────────────


def _make_parsed_case(
    nachname: str = "Tonn",
    vorname: str | None = "Regina",
    geburtsdatum: date | None = date(1960, 4, 28),
    kvnr: str | None = "D410126355",
    fallgruppe: str = "kardio",
    datum: date = date(2026, 2, 2),
    jahr: int = 2026,
    kw: int = 6,
    crm_ticket_id: str | None = "103486",
    thema: str = "Zweitmeinung",
) -> ParsedCase:
    """Create a ParsedCase with sensible defaults for testing."""
    return ParsedCase(
        nachname=nachname,
        vorname=vorname,
        geburtsdatum=geburtsdatum,
        kvnr=kvnr,
        thema=thema,
        fallgruppe=fallgruppe,
        datum=datum,
        jahr=jahr,
        kw=kw,
        crm_ticket_id=crm_ticket_id,
    )


# ── generate_fall_id tests ──────────────────────────────────────────────


class TestGenerateFallId:
    def test_format(self):
        """fall_id matches YYYY-KW-fallgruppe-KVNR format."""
        pc = _make_parsed_case(nachname="Tonn", kvnr="D410126355", fallgruppe="onko", jahr=2026, kw=6)
        result = generate_fall_id(pc)
        assert result == "2026-06-onko-D410126355"

    def test_kw_padding_single_digit(self):
        """KW < 10 is zero-padded to 2 digits."""
        pc = _make_parsed_case(kw=6)
        result = generate_fall_id(pc)
        assert "-06-" in result

    def test_kw_padding_double_digit(self):
        """KW >= 10 stays as-is (no extra padding)."""
        pc = _make_parsed_case(kw=12)
        result = generate_fall_id(pc)
        assert "-12-" in result

    def test_kw_padding_kw1(self):
        """KW 1 is zero-padded to 01."""
        pc = _make_parsed_case(kw=1)
        result = generate_fall_id(pc)
        assert "-01-" in result

    def test_different_cases_produce_different_ids(self):
        """Different KVNRs/fallgruppen produce unique fall_ids."""
        pc1 = _make_parsed_case(kvnr="A111111111", fallgruppe="onko")
        pc2 = _make_parsed_case(kvnr="B222222222", fallgruppe="intensiv")
        pc3 = _make_parsed_case(kvnr="A111111111", fallgruppe="kardio")
        ids = {generate_fall_id(pc1), generate_fall_id(pc2), generate_fall_id(pc3)}
        assert len(ids) == 3

    def test_same_patient_same_week_same_fallgruppe(self):
        """Same KVNR in same week and fallgruppe produces same fall_id."""
        pc1 = _make_parsed_case(kvnr="A111111111", fallgruppe="onko", kw=8)
        pc2 = _make_parsed_case(kvnr="A111111111", fallgruppe="onko", kw=8)
        assert generate_fall_id(pc1) == generate_fall_id(pc2)

    def test_random_suffix_when_no_kvnr(self):
        """fall_id uses 6-char random suffix when KVNR is missing."""
        pc = _make_parsed_case(kvnr=None, fallgruppe="onko", jahr=2026, kw=6)
        result = generate_fall_id(pc)
        parts = result.split("-")
        assert parts[0] == "2026"
        assert parts[1] == "06"
        assert parts[2] == "onko"
        suffix = parts[3]
        assert len(suffix) == 6
        assert suffix.isalnum()
        assert suffix == suffix.upper()

    def test_random_suffix_when_empty_kvnr(self):
        """fall_id uses random suffix when KVNR is empty string."""
        pc = _make_parsed_case(kvnr="", fallgruppe="onko", jahr=2026, kw=6)
        result = generate_fall_id(pc)
        parts = result.split("-")
        suffix = parts[3]
        assert len(suffix) == 6
        assert suffix.isalnum()

    def test_all_fallgruppen(self):
        """fall_id works for all valid fallgruppen."""
        for fg in ["onko", "kardio", "intensiv", "galle", "sd"]:
            pc = _make_parsed_case(nachname="Test", fallgruppe=fg, kw=10)
            result = generate_fall_id(pc)
            assert f"-{fg}-" in result

    def test_year_boundary(self):
        """fall_id uses ISO year (from ParsedCase.jahr), not calendar year."""
        # ISO week 1 of 2027 might start in Dec 2026
        pc = _make_parsed_case(jahr=2027, kw=1)
        result = generate_fall_id(pc)
        assert result.startswith("2027-")


# ── generate_random_suffix tests ───────────────────────────────────────


class TestGenerateRandomSuffix:
    def test_length(self):
        assert len(generate_random_suffix()) == 6

    def test_charset(self):
        """Only uppercase letters and digits."""
        import re
        for _ in range(50):
            s = generate_random_suffix()
            assert re.match(r'^[A-Z0-9]{6}$', s)

    def test_uniqueness(self):
        """Different calls produce different suffixes."""
        suffixes = {generate_random_suffix() for _ in range(20)}
        assert len(suffixes) >= 15


# ── ImportRow schema tests ──────────────────────────────────────────────


class TestImportRowSchema:
    def test_minimal_row(self):
        """ImportRow can be created with only required fields."""
        row = ImportRow(
            row_number=1,
            nachname="Tonn",
            fallgruppe="onko",
            datum=date(2026, 2, 2),
        )
        assert row.vorname is None
        assert row.geburtsdatum is None
        assert row.kvnr is None
        assert row.is_duplicate is False
        assert row.fall_id is None

    def test_full_row(self):
        """ImportRow with all fields populated."""
        row = ImportRow(
            row_number=1,
            nachname="Tonn",
            vorname="Regina",
            geburtsdatum=date(1960, 4, 28),
            kvnr="D410126355",
            fallgruppe="kardio",
            datum=date(2026, 2, 2),
            is_duplicate=True,
            fall_id="2026-06-kardio-D410126355",
        )
        assert row.is_duplicate is True
        assert row.fall_id == "2026-06-kardio-D410126355"


# ── ImportPreview schema tests ──────────────────────────────────────────


class TestImportPreviewSchema:
    def test_empty_preview(self):
        """ImportPreview for empty CSV."""
        preview = ImportPreview(
            filename="test.csv",
            total_rows=0,
            new_cases=0,
            duplicates=0,
        )
        assert preview.rows == []
        assert preview.errors == []

    def test_preview_counts(self):
        """ImportPreview counts are consistent."""
        preview = ImportPreview(
            filename="test.csv",
            total_rows=10,
            new_cases=7,
            duplicates=3,
        )
        assert preview.total_rows == preview.new_cases + preview.duplicates


# ── ImportResult schema tests ──────────────────────────────────────────


class TestImportResultSchema:
    def test_clean_result(self):
        """ImportResult with no errors."""
        result = ImportResult(imported=5, skipped=2, updated=0)
        assert result.errors == []

    def test_result_with_errors(self):
        """ImportResult with error messages."""
        result = ImportResult(
            imported=3,
            skipped=1,
            updated=0,
            errors=["Tonn: some error", "Daum: other error"],
        )
        assert len(result.errors) == 2


# ── check_duplicate with mocked DB ─────────────────────────────────────


class TestCheckDuplicateMocked:
    def _mock_db_no_results(self):
        """Create a mock DB session that returns no results."""
        db = MagicMock()
        query = MagicMock()
        db.query.return_value = query
        query.filter.return_value = query
        query.first.return_value = None
        return db

    def _mock_db_fall_id_match(self):
        """Create a mock DB session that finds a fall_id match."""
        db = MagicMock()
        query = MagicMock()
        db.query.return_value = query
        query.filter.return_value = query
        # First call to .first() (fall_id check) returns a result
        query.first.return_value = MagicMock()
        return db

    def test_no_duplicate(self):
        """Returns False when no matching case found."""
        db = self._mock_db_no_results()
        pc = _make_parsed_case()
        assert check_duplicate(db, pc) is False

    def test_fall_id_duplicate(self):
        """Returns True when fall_id already exists."""
        db = self._mock_db_fall_id_match()
        pc = _make_parsed_case()
        assert check_duplicate(db, pc) is True


# ── preview_import with mocked DB ──────────────────────────────────────


class TestPreviewImportMocked:
    def test_preview_all_new(self):
        """Preview with no duplicates in DB."""
        db = MagicMock()
        query = MagicMock()
        db.query.return_value = query
        query.filter.return_value = query
        query.first.return_value = None

        cases = [
            _make_parsed_case(nachname="Tonn"),
            _make_parsed_case(nachname="Daum", fallgruppe="intensiv"),
        ]
        result = preview_import(db, cases, "test.csv")

        assert result.total_rows == 2
        assert result.new_cases == 2
        assert result.duplicates == 0
        assert len(result.rows) == 2
        assert result.rows[0].fall_id is not None
        assert result.rows[1].fall_id is not None
        assert not result.rows[0].is_duplicate
        assert not result.rows[1].is_duplicate

    def test_preview_with_duplicates(self):
        """Preview where some cases are duplicates."""
        db = MagicMock()
        query = MagicMock()
        db.query.return_value = query
        query.filter.return_value = query

        # First case: fall_id match (duplicate), second case: no match
        query.first.side_effect = [MagicMock(), None, None]

        cases = [
            _make_parsed_case(nachname="Tonn"),
            _make_parsed_case(nachname="Daum", fallgruppe="intensiv"),
        ]
        result = preview_import(db, cases, "test.csv")

        assert result.total_rows == 2
        assert result.new_cases == 1
        assert result.duplicates == 1
        assert result.rows[0].is_duplicate is True
        assert result.rows[1].is_duplicate is False

    def test_preview_empty(self):
        """Preview with empty list of cases."""
        db = MagicMock()
        result = preview_import(db, [], "empty.csv")
        assert result.total_rows == 0
        assert result.new_cases == 0
        assert result.duplicates == 0
        assert result.rows == []

    def test_preview_row_numbers_start_at_one(self):
        """Row numbers in preview are 1-indexed."""
        db = MagicMock()
        query = MagicMock()
        db.query.return_value = query
        query.filter.return_value = query
        query.first.return_value = None

        cases = [
            _make_parsed_case(nachname="A"),
            _make_parsed_case(nachname="B"),
            _make_parsed_case(nachname="C"),
        ]
        result = preview_import(db, cases, "test.csv")

        assert result.rows[0].row_number == 1
        assert result.rows[1].row_number == 2
        assert result.rows[2].row_number == 3