"""The candidate fingerprint: which changes are major, minor or nothing, and what never counts."""

from __future__ import annotations

import dataclasses
from collections.abc import Callable
from datetime import date
from decimal import Decimal
from typing import Any

import pytest

from packetstation.feed import fingerprint as fp
from packetstation.feed.candidates import BomLine, Candidate, Folded, Leg
from packetstation.feed.types import WoKey

K1 = WoKey("L900-01", "1", "0", "0")
K2 = WoKey("L900-02", "1", "0", "0")


def leg(key: WoKey = K1, seq: int = 20, qty: Any = "2", tgt: Any = "3", **over: Any) -> Leg:
    values: dict[str, Any] = {
        "key": key,
        "seq": seq,
        "op": "WELD-PART",
        "qty": Decimal(str(qty)),
        "tgt": Decimal(str(tgt)),
        "dwg": "L900-0101",
        "rev": "1",
        "partspecs": "",
        "st": "F",
    }
    values.update(over)
    return Leg(**values)


def line(item: str = "1", part: str | None = "PIPE-6", qty: Any = "2", **over: Any) -> BomLine:
    values: dict[str, Any] = {
        "item": item,
        "qty": Decimal(str(qty)),
        "part_id": part or "",
        "desc": "Pipe",
        "loc": "R1",
        "whs": "SHOP",
        "comm": "PIPE",
        "cons": False,
        "sub": False,
        "na": False,
        "grp": None,
        "vkey": f"L900-01|1|0|20|{item}",
        "issued": Decimal(0),
        "istat": 2,
    }
    values.update(over)
    return BomLine(**values)


def cand(**over: Any) -> Candidate:
    values: dict[str, Any] = {
        "key": "L900001|WELD-PART|L900-0101",
        "project": "L900",
        "unit": "L900001",
        "lot": "1",
        "dept": "03",
        "op": "WELD-PART",
        "drawing": "L900-0101",
        "rev": "1",
        "title": "Inlet spool",
        "legs": [leg()],
        "folded": [],
        "partspecs": [],
        "rel": date(2026, 10, 10),
        "want": date(2026, 11, 5),
        "bom": [line("1"), line("2", "ELB-6", "1")],
        "statuses": {K1: "F"},
        "base": "L900-01",
        "in_window": True,
    }
    values.update(over)
    return Candidate(**values)


def classify(before: Candidate, after: Candidate) -> fp.Change:
    return fp.classify(fp.compute(before).parts, fp.compute(after).parts)


MAJOR_EDITS: dict[str, tuple[str, Callable[[], dict[str, Any]]]] = {
    "leg added": ("legs", lambda: {"legs": [leg(), leg(K2, 10)]}),
    "leg removed": ("legs", lambda: {"legs": []}),
    "leg seq": ("legs", lambda: {"legs": [leg(seq=30)]}),
    "qty": ("qty", lambda: {"legs": [leg(qty="3")]}),
    "rev": ("rev", lambda: {"rev": "2"}),
    "drawing": ("drawing", lambda: {"drawing": "L900-0102"}),
    "bom item": ("bom", lambda: {"bom": [line("1"), line("3", "ELB-6", "1")]}),
    "bom part": ("bom", lambda: {"bom": [line("1"), line("2", "ELB-6-SR", "1")]}),
    "bom qty": ("bom", lambda: {"bom": [line("1"), line("2", "ELB-6", "2")]}),
    "bom line added": ("bom", lambda: {"bom": [line("1"), line("2", "ELB-6", "1"), line("3", "TEE-6", "1")]}),
}


@pytest.mark.parametrize("name", list(MAJOR_EDITS))
def test_major_change(name: str) -> None:
    part, edit = MAJOR_EDITS[name]
    ch = classify(cand(), cand(**edit()))
    assert ch.changed and not ch.is_minor
    assert part in ch.major


MINOR_EDITS: dict[str, tuple[str, Callable[[], dict[str, Any]]]] = {
    "tgt": ("tgt", lambda: {"legs": [leg(tgt="3.5")]}),
    "want": ("want", lambda: {"want": date(2026, 11, 12)}),
    "want cleared": ("want", lambda: {"want": None}),
}


@pytest.mark.parametrize("name", list(MINOR_EDITS))
def test_minor_change(name: str) -> None:
    part, edit = MINOR_EDITS[name]
    ch = classify(cand(), cand(**edit()))
    assert ch.changed and ch.is_minor
    assert ch.major == frozenset() and ch.minor == frozenset({part})


def test_minor_and_major_together_is_major() -> None:
    ch = classify(cand(), cand(rev="2", want=date(2026, 12, 1)))
    assert ch.major == {"rev"} and ch.minor == {"want"} and not ch.is_minor


NEVER_EDITS: dict[str, Callable[[], dict[str, Any]]] = {
    "rel": lambda: {"rel": date(2026, 10, 1)},
    "folded": lambda: {"folded": [Folded(K1, 30, "MFG", Decimal("0.5"))]},
    "partspecs": lambda: {"partspecs": ["Weld per WPS-11"]},
    "title": lambda: {"title": "Another title"},
    "statuses": lambda: {"statuses": {K1: "R"}},
    "issued": lambda: {"bom": [line("1", issued=Decimal(2)), line("2", "ELB-6", "1")]},
    "whs": lambda: {"bom": [line("1", whs="MAIN"), line("2", "ELB-6", "1")]},
    "loc": lambda: {"bom": [line("1", loc="A-01"), line("2", "ELB-6", "1")]},
    "dept and op": lambda: {"dept": "06", "op": "WELD-CODE"},
    "leg status": lambda: {"legs": [leg(st="C")]},
    "leg partspecs": lambda: {"legs": [leg(partspecs="Back purge")]},
    "in_window": lambda: {"in_window": False},
}


@pytest.mark.parametrize("name", list(NEVER_EDITS))
def test_never_in_the_fingerprint(name: str) -> None:
    before, after = cand(), cand(**NEVER_EDITS[name]())
    assert not classify(before, after).changed
    assert fp.compute(before).full == fp.compute(after).full


INVARIANT: dict[str, tuple[Callable[[], dict[str, Any]], Callable[[], dict[str, Any]]]] = {
    "2 vs 2.0": (lambda: {"legs": [leg(qty="2")]}, lambda: {"legs": [leg(qty="2.0")]}),
    "trailing zeros": (lambda: {"legs": [leg(tgt="1.5")]}, lambda: {"legs": [leg(tgt="1.500")]}),
    "empty vs None rev": (lambda: {"rev": ""}, lambda: {"rev": None}),
    "list order": (
        lambda: {"legs": [leg(), leg(K2, 10)], "bom": [line("1"), line("2", "ELB-6", "1")]},
        lambda: {"legs": [leg(K2, 10), leg()], "bom": [line("2", "ELB-6", "1"), line("1")]},
    ),
    "drawing case and spaces": (lambda: {"drawing": "m00543"}, lambda: {"drawing": " M00 543 "}),
    "part id case": (
        lambda: {"bom": [line("1", "m00543")]},
        lambda: {"bom": [line("1", "M00543")]},
    ),
    "CRLF": (lambda: {"rev": "1\r\n"}, lambda: {"rev": "1\n"}),
}


@pytest.mark.parametrize("name", list(INVARIANT))
def test_invariance(name: str) -> None:
    a, b = INVARIANT[name]
    assert fp.compute(cand(**a())).full == fp.compute(cand(**b())).full


def test_lot_7a_stays_text() -> None:
    k = WoKey("L900-14", "7A", "0", "0")
    c = cand(legs=[leg(k, 10)], statuses={k: "F"})
    values = fp.part_values(c)
    assert values["legs"] == [["L900-14", "7A", "0", "0", 10]]
    # A lot with leading zeros is not a number either
    k0 = WoKey("L900-14", "007", "0", "0")
    other = fp.part_values(cand(legs=[leg(k0, 10)]))
    assert other["legs"][0][1] == "007"
    assert fp.compute(c).full != fp.compute(cand(legs=[leg(k0, 10)])).full


def test_canonical_is_stable_json() -> None:
    assert fp.canonical({"b": Decimal("2.0"), "a": ["x\r\n", None, ""]}) == b'{"a":["x",null,null],"b":"2"}'
    assert fp.canonical({"d": date(2026, 10, 16)}) == b'{"d":"2026-10-16"}'
    assert fp.canonical("é") == fp.canonical("é")  # NFC


def test_parts_and_full() -> None:
    f = fp.compute(cand())
    assert set(f.parts) == set(fp.MAJOR) | set(fp.MINOR)
    assert all(len(v) == 64 for v in f.parts.values()) and len(f.full) == 64
    assert fp.compute(cand()) == f  # deterministic


def test_no_before_is_all_changed() -> None:
    ch = fp.classify(None, fp.compute(cand()).parts)
    assert ch.major == frozenset(fp.MAJOR) and ch.minor == frozenset(fp.MINOR)


def test_unknown_materials_are_not_a_bom_change() -> None:
    before = fp.compute(cand())
    after = fp.compute(cand(bom=None))
    assert "bom" not in classify(cand(), cand(bom=None)).major
    merged = fp.merge(before.parts, after)
    assert merged.parts["bom"] == before.parts["bom"] and merged.full == before.full


def test_dataclass_copy_is_unchanged() -> None:
    c = cand()
    assert fp.compute(dataclasses.replace(c)).full == fp.compute(c).full