"""
Library for handling KiCad's footprint files (`*.kicad_mod`).
"""

import re
import copy
import enum
import string
import datetime
import math
import time
import fnmatch
from itertools import chain
from pathlib import Path
from dataclasses import field, replace

from .sexp import *
from .base_types import *
from .primitives import *
from . import graphical_primitives as gr

from ..primitives import Positioned

from ... import graphic_primitives as gp
from ... import graphic_objects as go
from ... import apertures as ap
from ...layers import LayerStack
from ...newstroke import Newstroke
from ...utils import MM, rotate_point, offset_bounds, sum_bounds
from ...aperture_macros.parse import GenericMacros, ApertureMacro
from ...aperture_macros import primitive as amp


class _MISSING:
    pass

def angle_difference(a, b):
    return (b - a + math.pi) % (2*math.pi) - math.pi

@sexp_type('attr')
class Attribute:
    type: AtomChoice(Atom.smd, Atom.through_hole) = None
    board_only: Flag() = False
    virtual: Flag() = False # prior to 20208026
    exclude_from_pos_files: Flag() = False
    exclude_from_bom: Flag() = False
    allow_missing_courtyard: Flag() = False
    allow_soldermask_bridges: Flag() = False
    dnp: Flag() = False


@sexp_type('fp_text')
class Text:
    type: AtomChoice(Atom.reference, Atom.value, Atom.user) = Atom.user
    text: str = ""
    at: AtPos = field(default_factory=AtPos)
    unlocked: Flag() = False
    layer: Named(str) = None
    hide: Flag() = False
    effects: TextEffect = field(default_factory=TextEffect)
    tstamp: Timestamp = None

    def render(self, variables={}, cache=None):
        if self.hide: # why
            return

        yield from gr.Text.render(self, variables=variables)


@sexp_type('fp_text_box')
class TextBox:
    locked: Flag() = False
    text: str = None
    start: Rename(XYCoord) = None
    end: Named(XYCoord) = None
    pts: PointList = None
    angle: Named(float) = 0.0
    layer: Named(str) = None
    tstamp: Timestamp = None
    effects: TextEffect = field(default_factory=TextEffect)
    stroke: Stroke = field(default_factory=Stroke)
    render_cache: RenderCache = None

    def render(self, variables={}, cache=None):
        yield from gr.TextBox.render(self, variables=variables)


@sexp_type('fp_line')
class Line:
    start: Rename(XYCoord) = None
    end: Rename(XYCoord) = None
    layer: Named(str) = None
    width: Named(float) = None
    stroke: Stroke = None
    locked: Flag() = False
    tstamp: Timestamp = None

    def to_graphical_primitive(self, flip=False):
        # FIXME flip
        return gr.Line(self.start, self.end, self.layer, self.width, self.stroke, self.tstamp)

    def render(self, variables=None, cache=None):
        dasher = Dasher(self)
        dasher.move(self.start.x, self.start.y)
        dasher.line(self.end.x, self.end.y)

        for x1, y1, x2, y2 in dasher:
            yield go.Line(x1, y1, x2, y2, aperture=ap.CircleAperture(dasher.width, unit=MM), unit=MM)


@sexp_type('fp_rect')
class Rectangle:
    start: Rename(XYCoord) = None
    end: Rename(XYCoord) = None
    layer: Named(str) = None
    width: Named(float) = None
    stroke: Stroke = None
    fill: Named(AtomChoice(Atom.solid, Atom.none)) = None
    locked: Flag() = False
    tstamp: Timestamp = None

    def render(self, variables=None, cache=None):
        x1, y1 = self.start.x, self.start.y
        x2, y2 = self.end.x, self.end.y
        x1, x2 = min(x1, x2), max(x1, x2)
        y1, y2 = min(y1, y2), max(y1, y2)
        w, h = x2-x1, y2-y1

        if self.fill == Atom.solid:
            yield go.Region.from_rectangle(x1, y1, w, h, unit=MM)

        dasher = Dasher(self)
        dasher.move(x1, y1)
        dasher.line(x1, y2)
        dasher.line(x2, y2)
        dasher.line(x2, y1)
        dasher.close()

        aperture = ap.CircleAperture(dasher.width, unit=MM)
        for x1, y1, x2, y2 in dasher:
            yield go.Line(x1, y1, x2, y2, aperture=aperture, unit=MM)


@sexp_type('fp_circle')
class Circle:
    center: Rename(XYCoord) = None
    end: Rename(XYCoord) = None
    layer: Named(str) = None
    width: Named(float) = None
    stroke: Stroke = None
    fill: Named(AtomChoice(Atom.solid, Atom.none)) = None
    locked: Flag() = False
    tstamp: Timestamp = None

    def render(self, variables=None, cache=None):
        x, y = self.center.x, self.center.y
        r = math.dist((x, y), (self.end.x, self.end.y)) # insane

        dasher = Dasher(self)
        aperture = ap.CircleAperture(dasher.width or 0, unit=MM)

        circle = go.Arc.from_circle(x, y, r, aperture=aperture, unit=MM)

        if self.fill == Atom.solid:
            yield circle.to_region()

        if dasher.solid:
            yield circle

        else: # pain
            for line in circle.approximate(): # TODO precision settings
                dasher.segments.append((line.x1, line.y1, line.x2, line.y2))

            aperture = ap.CircleAperture(dasher.width, unit=MM)
            for x1, y1, x2, y2 in dasher:
                yield go.Line(x1, y1, x2, y2, aperture=aperture, unit=MM)


@sexp_type('fp_arc')
class Arc:
    start: Rename(XYCoord) = None
    mid: Rename(XYCoord) = None
    end: Rename(XYCoord) = None
    width: Named(float) = None
    stroke: Stroke = None
    layer: Named(str) = None
    locked: Flag() = False
    tstamp: Timestamp = None

    def to_graphical_primitive(self, flip=False):
        # FIXME flip
        return gr.Arc(self.start, self.mid, self.end, self.layer, self.width, self.stroke, self.tstamp)

    def render(self, variables=None, cache=None):
        mx, my = self.mid.x, self.mid.y
        x1, y1 = self.start.x, self.start.y
        x2, y2 = self.end.x, self.end.y
        dasher = Dasher(self)
        aperture = ap.CircleAperture(dasher.width, unit=MM)

        if math.isclose(x1, x2, abs_tol=1e-6) and math.isclose(y1, y2, abs_tol=1e-6):
            cx = (x1 + mx) / 2
            cy = (y1 + my) / 2
            arc = go.Arc(x1, y1, x2, y2, cx-x1, cy-y1, clockwise=True, aperture=aperture, unit=MM)
            if dasher.solid:
                yield arc

            else:
                # use approximation from graphic object arc class 
                for line in arc.approximate():
                    dasher.segments.append((line.x1, line.y1, line.x2, line.y2))
                
                for line in dasher:
                    yield go.Line(x1, y1, x2, y2, aperture=ap.CircleAperture(dasher.width, unit=MM), unit=MM)

        else:
            # https://stackoverflow.com/questions/56224824/how-do-i-find-the-circumcenter-of-the-triangle-using-python-without-external-lib
            d = 2 * (x1 * (y2 - my) + x2 * (my - y1) + mx * (y1 - y2))
            cx = ((x1 * x1 + y1 * y1) * (y2 - my) + (x2 * x2 + y2 * y2) * (my - y1) + (mx * mx + my * my) * (y1 - y2)) / d
            cy = ((x1 * x1 + y1 * y1) * (mx - x2) + (x2 * x2 + y2 * y2) * (x1 - mx) + (mx * mx + my * my) * (x2 - x1)) / d

        # KiCad only has clockwise arcs.
        arc = go.Arc(x1, y1, x2, y2, cx-x1, cy-y1, clockwise=False, aperture=aperture, unit=MM)
        if dasher.solid:
            yield arc

        else:
            # use approximation from graphic object arc class 
            for line in arc.approximate():
                dasher.segments.append((line.x1, line.y1, line.x2, line.y2))
            
            for line in dasher:
                yield go.Line(x1, y1, x2, y2, aperture=ap.CircleAperture(dasher.width, unit=MM), unit=MM)


@sexp_type('fp_poly')
class Polygon:
    pts: PointList = field(default_factory=PointList)
    layer: Named(str) = None
    width: Named(float) = None
    stroke: Stroke = None
    fill: Named(AtomChoice(Atom.solid, Atom.none)) = None
    locked: Flag() = False
    tstamp: Timestamp = None

    def render(self, variables=None, cache=None):
        if len(self.pts.xy) < 2:
            return

        dasher = Dasher(self)
        start = self.pts.xy[0]
        dasher.move(start.x, start.y)
        for point in self.pts.xy[1:]:
            dasher.line(point.x, point.y)

        aperture = ap.CircleAperture(dasher.width, unit=MM)
        for x1, y1, x2, y2 in dasher:
            yield go.Line(x1, y1, x2, y2, aperture=aperture, unit=MM)

        if self.fill == Atom.solid:
            yield go.Region([(pt.x, pt.y) for pt in self.pts.xy], unit=MM)


@sexp_type('fp_curve')
class Curve:
    pts: PointList = field(default_factory=PointList)
    layer: Named(str) = None
    width: Named(float) = None
    stroke: Stroke = None
    locked: Flag() = False
    tstamp: Timestamp = None

    def render(self, variables=None, cache=None):
        raise NotImplementedError('Bezier rendering is not yet supported. Please raise an issue and provide an example file.')


@sexp_type('format')
class DimensionFormat:
    prefix: Named(str) = None
    suffix: Named(str) = None
    units: Named(int) = 3
    units_format: Named(int) = 0
    precision: Named(int) = 3
    override_value: Named(str) = None
    suppress_zeros: Flag() = False


@sexp_type('style')
class DimensionStyle:
    thickness: Named(float) = None
    arrow_length: Named(float) = None
    text_position_mode: Named(int) = 0
    extension_height: Named(float) = None
    text_frame: Named(int) = 0
    extension_offset: Named(str) = None
    keep_text_aligned: Flag() = False


@sexp_type('dimension')
class Dimension:
    locked: Flag() = False
    type: AtomChoice(Atom.aligned, Atom.leader, Atom.center, Atom.orthogonal, Atom.radial) = None
    layer: Named(str) = None
    tstamp: Timestamp = None
    pts: PointList = field(default_factory=PointList)
    height: Named(float) = None
    orientation: Named(int) = 0
    leader_length: Named(float) = None
    gr_text: Named(Text) = None
    format: DimensionFormat = field(default_factory=DimensionFormat)
    style: DimensionStyle = field(default_factory=DimensionStyle)

    def render(self, variables=None, cache=None):
        raise NotImplementedError()


@sexp_type('drill')
class Drill:
    oval: Flag() = False
    diameter: float = 0
    width: float = None
    offset: Rename(XYCoord) = None


@sexp_type('net')
class NetDef:
    number: int = None
    name: str = None


@sexp_type('options')
class CustomPadOptions:
    clearance: Named(AtomChoice(Atom.outline, Atom.convexhull)) = Atom.outline
    anchor: Named(AtomChoice(Atom.rect, Atom.circle)) = Atom.rect


@sexp_type('primitives')
class CustomPadPrimitives:
    annotation_bboxes: List(gr.AnnotationBBox) = field(default_factory=list)
    lines: List(gr.Line) = field(default_factory=list)
    rectangles: List(gr.Rectangle) = field(default_factory=list)
    circles: List(gr.Circle) = field(default_factory=list)
    arcs: List(gr.Arc) = field(default_factory=list)
    polygons: List(gr.Polygon) = field(default_factory=list)
    curves: List(gr.Curve) = field(default_factory=list)
    width: Named(float) = None
    fill: Named(YesNoAtom()) = True

    def all(self):
        yield from self.lines
        yield from self.rectangles
        yield from self.circles
        yield from self.arcs
        yield from self.polygons
        yield from self.curves


@sexp_type('chamfer')
class Chamfer:
    top_left: Flag() = False
    top_right: Flag() = False
    bottom_left: Flag() = False
    bottom_right: Flag() = False


@sexp_type('pad')
class Pad:
    number: str = None
    type: AtomChoice(Atom.thru_hole, Atom.smd, Atom.connect, Atom.np_thru_hole) = None
    shape: AtomChoice(Atom.circle, Atom.rect, Atom.oval, Atom.trapezoid, Atom.roundrect, Atom.custom) = None
    at: AtPos = field(default_factory=AtPos)
    locked: Flag() = False
    size: Rename(XYCoord) = field(default_factory=XYCoord)
    drill: Drill = None
    layers: Named(Array(str)) = field(default_factory=list)
    properties: List(Property) = field(default_factory=list)
    remove_unused_layers: Wrap(Flag()) = False
    keep_end_layers: Wrap(Flag()) = False
    rect_delta: Rename(XYCoord) = None
    roundrect_rratio: Named(float) = None
    thermal_bridge_angle: Named(int) = 45
    thermal_bridge_width: Named(float) = 0.5
    chamfer_ratio: Named(float) = None
    chamfer: Chamfer = None
    net: NetDef = None
    tstamp: Timestamp = None
    pin_function: Named(str) = None
    pintype: Named(str) = None
    pinfunction: Named(str) = None
    die_length: Named(float) = None
    solder_mask_margin: Named(float) = None
    solder_paste_margin: Named(float) = None
    solder_paste_margin_ratio: Named(float) = None
    clearance: Named(float) = None
    zone_connect: Named(int) = None
    thermal_width: Named(float) = None
    thermal_gap: Named(float) = None
    options: OmitDefault(CustomPadOptions) = None
    primitives: OmitDefault(CustomPadPrimitives) = None
    _: SEXP_END = None
    footprint: object = None

    def __after_parse__(self, parent=None):
        self.layers = unfuck_layers(self.layers)

    def __before_sexp__(self):
        self.layers = fuck_layers(self.layers)

    @property
    def abs_pos(self):
        if self.footprint:
            px, py, pr = self.footprint.at.x, self.footprint.at.y, self.footprint.at.rotation
        else:
            px, py, pr = 0, 0, 0

        x, y = rotate_point(self.at.x, self.at.y, math.radians(pr))
        return x+px, y+py, self.at.rotation, False

    @property
    def layer_mask(self):
        return layer_mask(self.layers)

    def offset(self, x=0, y=0):
        self.at = self.at.with_offset(x, y)

    def find_connected_footprints(self, **filters):
        """ Find footprints connected to the same net as this pad """
        return self.footprint.board.find_footprints(net=self.net.name, **filters)

    def find_same_net(self, include_vias=True):
        """ Find traces and vias of the same net as this pad. """ 
        return self.footprint.board.find_traces(self.net.name, include_vias=include_vias)

    def render(self, variables=None, margin=None, cache=None):
        #if self.type in (Atom.connect, Atom.np_thru_hole):
        #    return
        if self.drill and self.drill.offset:
            ox, oy = rotate_point(self.drill.offset.x, self.drill.offset.y, math.radians(self.at.rotation))
        else:
            ox, oy = 0, 0

        cache_key = id(self), margin
        if cache and cache_key in cache:
            aperture = cache[cache_key]

        elif cache is not None:
            aperture = cache[cache_key] = self.aperture(margin)

        else:
            aperture = self.aperture(margin)

        yield go.Flash(self.at.x+ox, self.at.y+oy, aperture, unit=MM)

    def aperture(self, margin=None):
        rotation = math.radians(self.at.rotation)
        margin = margin or 0

        if self.shape == Atom.circle:
            return ap.CircleAperture(self.size.x+2*margin, unit=MM)

        elif self.shape == Atom.rect:
            if margin > 0:
                return ap.ApertureMacroInstance(GenericMacros.rounded_rect,
                        (self.size.x+2*margin, self.size.y+2*margin,
                         margin,
                         0, 0, # no hole
                         rotation), unit=MM)
            else:
                return ap.RectangleAperture(self.size.x+2*margin, self.size.y+2*margin, unit=MM).rotated(rotation)

        elif self.shape == Atom.oval:
            return ap.ObroundAperture(self.size.x+2*margin, self.size.y+2*margin, unit=MM).rotated(rotation)

        elif self.shape == Atom.trapezoid:
            # KiCad's trapezoid aperture "rect_delta" param is just weird to the point that I think it's probably
            # bugged. If you have a size of 2mm by 2mm, and set this param to 1mm, the resulting pad extends past the
            # original bounding box, and the trapezoid's base and tip length are 3mm and 1mm.

            x, y = self.size.x, self.size.y
            if self.rect_delta:
                dx, dy = self.rect_delta.x, self.rect_delta.y
            else: # RF_Antenna/Pulse_W3011 has trapezoid pads w/o rect_delta, which KiCad renders as plain rects.
                dx, dy = 0, 0

            if dx != 0:
                x, y = y, x
                dy = dx
                rotation += math.pi/2

            if margin <= 0:
                # Note: KiCad already uses MM units, so no conversion needed here.

                alpha = math.atan(y / dy) if dy > 0 else 0
                return ap.ApertureMacroInstance(GenericMacros.isosceles_trapezoid,
                        (x+dy+2*margin*math.cos(alpha), y+2*margin,
                         2*dy,
                         0, 0, # no hole
                         rotation), unit=MM)

            else:
                return ap.ApertureMacroInstance(GenericMacros.rounded_isosceles_trapezoid,
                        (x+dy, y,
                         2*dy, margin,
                         0, 0, # no hole
                         rotation), unit=MM)

        elif self.shape == Atom.roundrect:
            x, y = self.size.x, self.size.y
            r = min(x, y) * self.roundrect_rratio
            if margin > -r:
                return ap.ApertureMacroInstance(GenericMacros.rounded_rect,
                        (x+2*margin, y+2*margin,
                         r+margin,
                         0, 0, # no hole
                         rotation), unit=MM)
            else:
                return ap.RectangleAperture(x+margin, y+margin, unit=MM).rotated(rotation)

        elif self.shape == Atom.custom:
            primitives = []

            # One round trip through the Gerbonara APIs, please!
            for obj in self.primitives.all():
                for gn_obj in obj.render():
                    if margin and isinstance(gn_obj, (go.Line, go.Arc)):
                        gn_obj = replace(gn_obj, aperture=gn_obj.aperture.dilated(margin))

                    if isinstance(gn_obj, go.Region) and margin > 0:
                        for line in gn_obj.outline_objects(ap.CircleAperture(2*margin, unit=MM)):
                            primitives += line._aperture_macro_primitives()

                    new_primitives = list(gn_obj._aperture_macro_primitives()) # todo: precision params
                    primitives += new_primitives

                    # inexact, only works with convex shapes. But whatever, the only other way to do this would require
                    # an entire polygon clipping/offsetting library. Probably a bad choice to put something this complex
                    # into a file format.
                    if isinstance(gn_obj, go.Region) and margin < 0:
                        for line in gn_obj.outline_objects(ap.CircleAperture(2*margin, unit=MM)):
                            line.polarity_dark = False
                            primitives += line._aperture_macro_primitives()

            if self.options:
                if self.options.anchor == Atom.rect and self.size.x > 0 and self.size.y > 0:
                    if margin <= 0:
                        primitives.append(amp.CenterLine(MM, 1, self.size.x+2*margin, self.size.y+2*margin, 0, 0, 0))

                    else: # margin > 0
                        primitives.append(amp.CenterLine(MM, 1, self.size.x+2*margin, self.size.y, 0, 0, 0))
                        primitives.append(amp.CenterLine(MM, 1, self.size.x, self.size.y+2*margin, 0, 0, 0))
                        primitives.append(amp.Circle(MM, 1, 2*margin, -self.size.x/2, -self.size.y/2))
                        primitives.append(amp.Circle(MM, 1, 2*margin, -self.size.x/2, +self.size.y/2))
                        primitives.append(amp.Circle(MM, 1, 2*margin, +self.size.x/2, -self.size.y/2))
                        primitives.append(amp.Circle(MM, 1, 2*margin, +self.size.x/2, +self.size.y/2))

                elif self.options.anchor == Atom.circle and self.size.x > 0:
                    primitives.append(amp.Circle(MM, 1, self.size.x+2*margin, 0, 0, 0))

            macro = ApertureMacro(primitives=tuple(primitives)).rotated(rotation)
            return ap.ApertureMacroInstance(macro, unit=MM)

    def render_drill(self):
        if not self.drill:
            return

        plated = self.type != Atom.np_thru_hole
        if self.drill.oval:
            dia = self.drill.diameter
            w = self.drill.width

            if self.drill.offset:
                ox, oy = self.drill.offset.x, self.drill.offset.y
            else:
                ox, oy = 0, 0
            
            if w > dia:
                dx = 0
                dy = (w-dia)/2
            else:
                dx = (dia-w)/2
                dy = 0

            aperture = ap.ExcellonTool(min(dia, w), plated=plated, unit=MM)
            l = go.Line(ox-dx, oy-dy, ox+dx, oy+dy, aperture=aperture, unit=MM) 
            l.rotate(math.radians(self.at.rotation))
            l.offset(self.at.x, self.at.y)
            yield l

        else:
            aperture = ap.ExcellonTool(self.drill.diameter, plated=plated, unit=MM)
            yield go.Flash(self.at.x, self.at.y, aperture=aperture, unit=MM) 


@sexp_type('model')
class Model:
    name: str = ''
    at: Named(XYZCoord) = field(default_factory=XYZCoord)
    offset: Named(XYZCoord) = field(default_factory=XYZCoord)
    scale: Named(XYZCoord) = field(default_factory=XYZCoord)
    rotate: Named(XYZCoord) = field(default_factory=XYZCoord)


SUPPORTED_FILE_FORMAT_VERSIONS = [20210108, 20211014, 20221018, 20230517]
@sexp_type('footprint')
class Footprint:
    name: str = None
    _version: Named(int, name='version') = 20221018
    generator: Named(Atom) = Atom.gerbonara
    locked: Flag() = False
    placed: Flag() = False
    layer: Named(str) = 'F.Cu'
    tedit: EditTime = field(default_factory=EditTime)
    tstamp: Timestamp = None
    at: AtPos = field(default_factory=AtPos)
    descr: Named(str) = None
    tags: Named(str) = None
    properties: List(DrawnProperty) = field(default_factory=list)
    path: Named(str) = None
    sheetname: Named(str) = None
    sheetfile: Named(str) = None
    autoplace_cost90: Named(float) = None
    autoplace_cost180: Named(float) = None
    solder_mask_margin: Named(float) = None
    solder_paste_margin: Named(float) = None
    solder_paste_ratio: Named(float) = None
    clearance: Named(float) = None
    zone_connect: Named(int) = None
    thermal_width: Named(float) = None
    thermal_gap: Named(float) = None
    attributes: Attribute = field(default_factory=list)
    private_layers: Named(str) = None
    net_tie_pad_groups: Named(Array(str)) = None
    texts: List(Text) = field(default_factory=list)
    text_boxes: List(TextBox) = field(default_factory=list)
    lines: List(Line) = field(default_factory=list)
    rectangles: List(Rectangle) = field(default_factory=list)
    circles: List(Circle) = field(default_factory=list)
    arcs: List(Arc) = field(default_factory=list)
    polygons: List(Polygon) = field(default_factory=list)
    curves: List(Curve) = field(default_factory=list)
    dimensions: List(Dimension) = field(default_factory=list)
    pads: List(Pad) = field(default_factory=list)
    zones: List(Zone) = field(default_factory=list)
    groups: List(Group) = field(default_factory=list)
    models: List(Model) = field(default_factory=list)
    _ : SEXP_END = None
    original_filename: str = None
    _bounding_box: tuple = None
    board: object = None

    def __after_parse__(self, parent):
        for pad in self.pads:
            pad.footprint = self

    def property_value(self, key, default=_MISSING):
        for prop in self.properties:
            if prop.key == key:
                return prop.value

        if default is not _MISSING:
            return default

        raise IndexError(f'Footprint has no property named "{key}"')

    def set_property(self, key, value, x=0, y=0, rotation=0, layer='F.Fab', hide=True, effects=None):
        for prop in self.properties:
            if prop.key == key:
                old_value, prop.value = prop.value, value
                return old_value

        if effects is None:
            effects = TextEffect()

        self.properties.append(DrawnProperty(key, value, 
                                             at=AtPos(x, y, rotation, unlocked=True),
                                             layer=layer,
                                             hide=hide,
                                             effects=effects))

    def make_standard_properties(self):
        if not self.property_value('Reference', None):
            self.set_property('Reference', 'REF**', 0, 0, 0, 'F.SilkS')

        if not self.property_value('Value', None):
            self.set_property('Value', self.name or 'VAL**', 0, 0, 0, hide=False)

        if not self.property_value('Footprint', None):
            self.set_property('Footprint', '', 0, 0, 0)

        if not self.property_value('Datasheet', None):
            self.set_property('Datasheet', '', 0, 0, 0)

        if not self.property_value('Description', None):
            self.set_property('Description', self.descr or '', 0, 0, 0)

    @property
    def pads_by_number(self):
        return {(int(pad.number) if pad.number.isnumeric() else pad.number): pad for pad in self.pads if pad.number}

    def find_pads(self, number=None, net=None):
        for pad in self.pads:
            if number is not None and pad.number == str(number):
                yield pad
            elif isinstance(net, str) and fnmatch.fnmatch(pad.net.name, net):
                yield pad
            elif net is not None and pad.net.number == net:
                yield pad

    def pad(self, number=None, net=None):
        candidates = list(self.find_pads(number=number, net=net))
        if not candidates:
            raise IndexError(f'No such pad "{number or net}"')

        if len(candidates) > 1:
            raise IndexError(f'Ambiguous pad "{number or net}", {len(candidates)} matching pads.')

        return candidates[0]

    def offset(self, x=0, y=0):
        self.at = self.at.with_offset(x, y)

    @property
    def version(self):
        return self._version

    @version.setter
    def version(self, value):
        if value not in SUPPORTED_FILE_FORMAT_VERSIONS:
            raise FormatError(f'File format version {value} is not supported. Supported versions are {", ".join(map(str, SUPPORTED_FILE_FORMAT_VERSIONS))}.')

    @property
    def reference(self):
        return self.property_value('Reference')

    @reference.setter
    def reference(self, value):
        self.set_property('Reference', value)

    @property
    def parsed_reference(self):
        ref = self.reference
        if (m := re.match(r'^.*[^0-9]([0-9]+)$', ref)):
            return m.group(0), int(m.group(1))
        else:
            return ref

    @property
    def value(self):
        return self.property_value('Value')

    @value.setter
    def value(self, value):
        self.set_property('Value', value)

    def write(self, filename=None):
        with open(filename or self.original_filename, 'w') as f:
            f.write(self.serialize())

    def serialize(self):
        return build_sexp(sexp(type(self), self)[0])

    @classmethod
    def open_pretty(kls, pretty_dir, fp_name, *args, **kwargs):
        pretty_dir = Path(pretty_dir) / f'{fp_name}.kicad_mod'
        return kls.open_mod(pretty_dir / mod_name, *args, **kwargs)

    @classmethod
    def open_mod(kls, mod_file, *args, **kwargs):
        return kls.load(Path(mod_file).read_text(), *args, **kwargs, original_filename=mod_file)

    @classmethod
    def open_system(kls, fp_path):
        raise NotImplementedError()

    @classmethod
    def open_download(kls, fp_path):
        raise NotImplementedError()

    @classmethod
    def load(kls, data, *args, **kwargs):
        return kls.parse(data, *args, **kwargs)

    @property
    def side(self):
        return 'front' if self.layer == 'F.Cu' else 'back'

    @side.setter
    def side(self, value):
        if value not in ('front', 'back'):
            raise ValueError(f'side must be either "front" or "back", not {side!r}')
        
        if self.side != value:
            self.flip()

    def flip(self):
        def flip_layer(name):
            if name.startswith('F.'):
                return f'B.{name[2:]}'
            elif name.startswith('B.'):
                return f'F.{name[2:]}'
            else:
                return name

        self.layer = flip_layer(self.layer)
        for obj in self.objects():
            if hasattr(obj, 'layer'):
                obj.layer = flip_layer(obj.layer)

            if hasattr(obj, 'layers'):
                obj.layers = [flip_layer(name) for name in obj.layers]

        for obj in chain(self.texts, self.text_boxes):
            obj.effects.justify.mirror = not obj.effects.justify.mirror

        for obj in self.properties:
            obj.effects.justify.mirror = not obj.effects.justify.mirror
            obj.layer = flip_layer(obj.layer)

    @property
    def single_sided(self):
        raise NotImplementedError()
    
    def face(self, direction, pad=None, net=None):
        if not net and not pad:
            pad = '1'

        candidates = list(self.find_pads(net=net, number=pad))
        if len(candidates) == 0:
            raise KeyError(f'Reference pad "{net or pad}" not found.')

        if len(candidates) > 1:
            raise KeyError(f'Reference pad "{net or pad}" is ambiguous, {len(candidates)} matching pads found.')

        pad = candidates[0]
        pad_angle = math.atan2(pad.at.y, pad.at.x)

        target_angle = {
                'right': 0,
                'top right': math.pi/4,
                'top': math.pi/2,
                'top left': 3*math.pi/4,
                'left': math.pi,
                'bottom left': -3*math.pi/4,
                'bottom': -math.pi/2,
                'bottom right': -math.pi/4}.get(direction, direction)
        
        delta = angle_difference(target_angle, pad_angle)
        adj = round(delta / (math.pi/2)) * math.pi/2
        self.set_rotation(adj)
        
    def rotate(self, angle=None, cx=None, cy=None, **reference_pad):
        """ Rotate this footprint by the given angle in radians, counter-clockwise. When (cx, cy) are given, rotate
        around the given coordinates in the global coordinate space. Otherwise rotate around the footprint's origin. """
        if (cx, cy) != (None, None):
            x, y = self.at.x-cx, self.at.y-cy
            self.at.x = math.cos(angle)*x - math.sin(angle)*y + cx
            self.at.y = math.sin(angle)*x + math.cos(angle)*y + cy

        self.at.rotation = (self.at.rotation - math.degrees(angle)) % 360

        for pad in self.pads:
            pad.at.rotation = (pad.at.rotation - math.degrees(angle)) % 360

        for prop in self.properties:
            prop.at.rotation = (prop.at.rotation - math.degrees(angle)) % 360

        for text in self.texts:
            text.at.rotation = (text.at.rotation - math.degrees(angle)) % 360

    def set_rotation(self, angle):
        old_deg = self.at.rotation
        new_deg = self.at.rotation = -math.degrees(angle)
        delta = new_deg - old_deg

        for pad in self.pads:
            pad.at.rotation = (pad.at.rotation + delta) % 360

        for prop in self.properties:
            prop.at.rotation = (prop.at.rotation + delta) % 360

        for text in self.texts:
            text.at.rotation = (text.at.rotation + delta) % 360

    def objects(self, text=False, pads=True, groups=True):
        return chain(
                (self.texts if text else []),
                (self.text_boxes if text else []),
                self.lines,
                self.rectangles,
                self.circles,
                self.arcs,
                self.polygons,
                self.curves,
                (self.dimensions if text else []),
                (self.pads if pads else []),
                self.zones,
                self.groups if groups else [])

    def render(self, layer_stack, layer_map, x=0, y=0, rotation=0, text=False, flip=False, variables={}, cache=None):
        x += self.at.x
        y += self.at.y
        rotation += math.radians(self.at.rotation)

        for obj in self.objects(pads=False, text=text):
            if not (layer := layer_map.get(obj.layer)):
                continue

            for fe in obj.render(variables=variables):
                fe.rotate(rotation)
                fe.offset(x, y, MM)
                layer_stack[layer].objects.append(fe)

        for obj in self.pads:
            if self.solder_mask_margin is not None:
                solder_mask_margin = self.solder_mask_margin
            elif obj.solder_mask_margin is not None:
                solder_mask_margin = obj.solder_mask_margin
            else:
                solder_mask_margin = None

            if self.solder_paste_margin is not None:
                solder_paste_margin = self.solder_paste_margin
            elif obj.solder_paste_margin_ratio is not None:
                solder_paste_margin = max(obj.size.x, obj.size.y) * obj.solder_paste_margin_ratio
            elif obj.solder_paste_margin is not None:
                solder_paste_margin = obj.solder_paste_margin
            else:
                solder_paste_margin = None

            for glob in obj.layers or []:
                for layer in fnmatch.filter(layer_map, glob):

                    if layer.endswith('.Mask'):
                        margin = solder_mask_margin
                    elif layer.endswith('.Paste'):
                        margin = solder_paste_margin
                    else:
                        margin = None

                    for fe in obj.render(margin=margin, cache=cache):
                        fe.rotate(rotation)
                        fe.offset(x, y, MM)
                        if isinstance(fe, go.Flash) and fe.aperture:
                            fe.aperture = fe.aperture.rotated(rotation)
                        layer_stack[layer_map[layer]].objects.append(fe)

        for obj in self.pads:
            for fe in obj.render_drill():
                fe.rotate(rotation)
                fe.offset(x, y, MM)

                if obj.type == Atom.np_thru_hole:
                    layer_stack.drill_npth.append(fe)
                else:
                    layer_stack.drill_pth.append(fe)
    
    def bounding_box(self, unit=MM):
        if not self._bounding_box:
            stack = LayerStack()
            layer_map = {kc_id: gn_id for kc_id, gn_id in LAYER_MAP_K2G.items() if gn_id in stack}
            self.render(stack, layer_map, x=0, y=0, rotation=0, flip=False, text=False, variables={})
            self._bounding_box = stack.bounding_box(unit)
        return self._bounding_box

        
@dataclass
class FootprintInstance(Positioned):
    sexp: Footprint = None
    hide_text: bool = True 
    reference: str = 'REF**'
    value: str = None
    variables: dict = field(default_factory=lambda: {})

    def render(self, layer_stack, cache=None):
        x, y, rotation, flip= self.abs_pos
        x, y = MM(x, self.unit), MM(y, self.unit)

        variables = dict(self.variables)

        if self.reference is not None:
            variables['REFERENCE'] = str(self.reference)

        if self.value is not None:
            variables['VALUE'] = str(self.value)

        layer_map = {kc_id: gn_id for kc_id, gn_id in LAYER_MAP_K2G.items() if gn_id in layer_stack}

        self.sexp.render(layer_stack, layer_map,
                         x=x, y=y, rotation=rotation,
                         flip=flip,
                         text=(not self.hide_text),
                         variables=variables, cache=cache)
    
    def bounding_box(self, unit=MM):
        return offset_bounds(self.sexp.bounding_box(unit), unit(self.x, self.unit), unit(self.y, self.unit))


if __name__ == '__main__':
    import sys
    from ...layers import LayerStack
    fp = Footprint.open_mod(sys.argv[1])
    stack = LayerStack()
    FootprintInstance(0, 0, fp, unit=MM).render(stack)
    print(stack.to_pretty_svg())
    stack.save_to_directory('/tmp/testdir')