"""PCB writer regression: synthetic PCB doc → kicad_pcb → re-parse."""

import math

from tools.epro2.kicad._sexpr_reader import parse
from tools.epro2.kicad.pcb_writer import MIL_TO_MM, write_pcb
from tools.epro2.project_relations import ProjectRelations
from tools.epro2.replay import Document, Project


def _close(a, b):
    """Float-close: 6-decimal s-expr roundtrip can lose strict equality."""
    return math.isclose(a, b, abs_tol=1e-6)


def _block(parsed, name):
    return [c for c in parsed if isinstance(c, list) and c and c[0] == name]


def _pcb(objs, doc_uuid="pcb1") -> Document:
    d = Document(doc_uuid=doc_uuid, doc_type="PCB")
    d.head = {"docType": "PCB", "editVersion": "3.2.91"}
    for k, v in objs:
        d.objects[k] = v
    return d


def _empty_pr(pcb_doc: Document) -> ProjectRelations:
    p = Project(project_uuid="p")
    p.documents[pcb_doc.doc_uuid] = pcb_doc
    return ProjectRelations.build(p)


def test_writer_emits_header_and_layers():
    d = _pcb([("META", {"_type": "META", "title": "BoardX"})])
    text = write_pcb(d, project_relations=_empty_pr(d))
    p = parse(text)
    assert p[0] == "kicad_pcb"
    layers = _block(p, "layers")[0]
    # F.Cu is always ordinal 0, B.Cu always 31 — KiCad convention.
    rows = [row for row in layers[1:] if isinstance(row, list)]
    by_name = {r[1]: r[0] for r in rows}
    assert by_name["F.Cu"] == 0
    assert by_name["B.Cu"] == 31
    assert "Edge.Cuts" in by_name


def test_inner_signal_layers_inserted_in_id_order():
    """An EPRO2 4-layer board with SIGNAL ids 15 and 16 actually used must
    map to In1.Cu and In2.Cu (in EPRO2-id sorted order) so the PCB
    layer-stack ordering matches the editor's intent."""
    d = _pcb([
        ('["LAYER",1]', {"_type": "LAYER", "layerType": "TOP", "use": True}),
        ('["LAYER",2]', {"_type": "LAYER", "layerType": "BOTTOM", "use": True}),
        ('["LAYER",15]', {"_type": "LAYER", "layerType": "SIGNAL", "use": True}),
        ('["LAYER",16]', {"_type": "LAYER", "layerType": "SIGNAL", "use": True}),
        # Drive "used" flag by including a primitive on each inner layer
        ("ln1", {"_type": "LINE", "layerId": 15,
                 "startX": 0, "startY": 0, "endX": 100, "endY": 0, "width": 6}),
        ("ln2", {"_type": "LINE", "layerId": 16,
                 "startX": 0, "startY": 0, "endX": 100, "endY": 0, "width": 6}),
    ])
    text = write_pcb(d, project_relations=_empty_pr(d))
    p = parse(text)
    rows = [r for r in _block(p, "layers")[0][1:] if isinstance(r, list)]
    cu_layers = [r[1] for r in rows if r[1].endswith(".Cu")]
    assert cu_layers == ["F.Cu", "In1.Cu", "In2.Cu", "B.Cu"]


def test_nets_get_stable_integer_ids_starting_at_1():
    """KiCad reserves net id 0 for "no net" — our user-defined nets must
    start at 1 so segments referencing them don't collide with the empty
    net."""
    d = _pcb([
        ('["NET","GND"]', {"_type": "NET"}),
        ('["NET","VCC"]', {"_type": "NET"}),
    ])
    text = write_pcb(d, project_relations=_empty_pr(d))
    p = parse(text)
    nets = _block(p, "net")
    by_name = {n[2]: n[1] for n in nets}
    assert by_name[""] == 0
    assert sorted([by_name["GND"], by_name["VCC"]]) == [1, 2]


def test_segment_emitted_for_copper_line_with_net():
    d = _pcb([
        ('["NET","GND"]', {"_type": "NET"}),
        ("ln1", {"_type": "LINE", "layerId": 1, "netName": "GND", "width": 6,
                 "startX": 100, "startY": 200, "endX": 500, "endY": 200}),
    ])
    text = write_pcb(d, project_relations=_empty_pr(d), board_origin_mm=(0.0, 0.0))
    p = parse(text)
    segs = _block(p, "segment")
    assert len(segs) == 1
    seg = segs[0]
    start = next(c for c in seg if isinstance(c, list) and c[0] == "start")
    end = next(c for c in seg if isinstance(c, list) and c[0] == "end")
    assert _close(start[1], 100 * MIL_TO_MM)
    assert _close(start[2], 200 * MIL_TO_MM)
    assert _close(end[1], 500 * MIL_TO_MM)
    layer = next(c for c in seg if isinstance(c, list) and c[0] == "layer")
    assert layer[1] == "F.Cu"
    net_ref = next(c for c in seg if isinstance(c, list) and c[0] == "net")
    assert net_ref[1] >= 1


def test_via_emitted_with_size_and_drill():
    d = _pcb([
        ('["NET","SIG"]', {"_type": "NET"}),
        ("v1", {"_type": "VIA", "centerX": 100, "centerY": 200,
                "viaDiameter": 24, "holeDiameter": 12, "netName": "SIG"}),
    ])
    text = write_pcb(d, project_relations=_empty_pr(d), board_origin_mm=(0.0, 0.0))
    p = parse(text)
    vias = _block(p, "via")
    assert len(vias) == 1
    v = vias[0]
    at = next(c for c in v if isinstance(c, list) and c[0] == "at")
    assert _close(at[1], 100 * MIL_TO_MM)
    size = next(c for c in v if isinstance(c, list) and c[0] == "size")
    assert _close(size[1], 24 * MIL_TO_MM)
    drill = next(c for c in v if isinstance(c, list) and c[0] == "drill")
    assert _close(drill[1], 12 * MIL_TO_MM)


def test_outline_poly_emitted_as_edge_cuts_lines():
    """POLY on layer 11 is the board outline and must convert to
    (gr_line ... (layer Edge.Cuts)) chains so KiCad recognises the
    board boundary — without this the board has no Edge.Cuts geometry
    and DRC reports invalid_outline."""
    d = _pcb([
        ("p1", {"_type": "POLY", "layerId": 11, "width": 4,
                "path": [0, 0, "L", 1000, 0, 1000, 1000, 0, 1000, 0, 0]}),
    ])
    text = write_pcb(d, project_relations=_empty_pr(d), board_origin_mm=(0.0, 0.0))
    p = parse(text)
    lines = _block(p, "gr_line")
    assert len(lines) == 4  # square: 4 sides
    layers = {next(c for c in ln if isinstance(c, list) and c[0] == "layer")[1]
              for ln in lines}
    assert layers == {"Edge.Cuts"}


def test_zero_length_segment_skipped():
    d = _pcb([
        ("ln1", {"_type": "LINE", "layerId": 1, "netName": "GND", "width": 6,
                 "startX": 5, "startY": 5, "endX": 5, "endY": 5}),
    ])
    text = write_pcb(d, project_relations=_empty_pr(d))
    p = parse(text)
    assert _block(p, "segment") == []
    assert getattr(write_pcb, "last_stats").skipped == 1


def test_non_pcb_doc_rejected():
    d = Document(doc_uuid="x", doc_type="SCH_PAGE")
    try:
        write_pcb(d)
    except ValueError:
        return
    raise AssertionError("expected ValueError for non-PCB doc")