import pcbnew
import wx
import math
import traceback


# ---------------------------------------------------------------------------
# Geometry
# ---------------------------------------------------------------------------

def _point_to_segment_dist(px, py, ax, ay, bx, by):
	dx, dy = bx - ax, by - ay
	if dx == 0 and dy == 0:
		return math.hypot(px - ax, py - ay)
	t = max(0.0, min(1.0, ((px - ax) * dx + (py - ay) * dy) / (dx * dx + dy * dy)))
	return math.hypot(px - (ax + t * dx), py - (ay + t * dy))


# ---------------------------------------------------------------------------
# Logic
# ---------------------------------------------------------------------------

def _build_candidates(board):
	"""Collect all non-via tracks and pads that have a real net."""
	candidates = []

	for track in board.GetTracks():
		if track.GetClass() == 'PCB_VIA':
			continue
		net = track.GetNet()
		if net and net.GetNetCode() != 0:
			candidates.append(('track', track, net))

	for pad in board.GetPads():
		net = pad.GetNet()
		if net and net.GetNetCode() != 0:
			candidates.append(('pad', pad, net))

	return candidates


def _nearest_net(via, candidates):
	vx = via.GetX()
	vy = via.GetY()
	vr = via.GetWidth() / 2

	best_net = None
	best_dist = None

	for kind, item, net in candidates:
		if kind == 'track':
			ax, ay = item.GetStart().x, item.GetStart().y
			bx, by = item.GetEnd().x, item.GetEnd().y
			hw = item.GetWidth() / 2
			dist = max(0.0, _point_to_segment_dist(vx, vy, ax, ay, bx, by) - hw - vr)
		else:  # pad
			dist = max(0.0, math.hypot(vx - item.GetX(), vy - item.GetY()) - vr)

		if best_dist is None or dist < best_dist:
			best_dist = dist
			best_net = net

	return best_net, best_dist


def assign_via_nets(board):
	vias = [t for t in board.GetTracks()
	        if t.GetClass() == 'PCB_VIA' and t.IsSelected()]

	if not vias:
		return 0, 'No vias in selection.'

	candidates = _build_candidates(board)
	if not candidates:
		return 0, 'No routed copper found on board.'

	count = 0
	for via in vias:
		net, _ = _nearest_net(via, candidates)
		if net is not None:
			via.SetNet(net)
			count += 1

	pcbnew.Refresh()
	return count, None


# ---------------------------------------------------------------------------
# Plugin
# ---------------------------------------------------------------------------

class Via_Net_Assign_Action(pcbnew.ActionPlugin):
	def defaults(self):
		self.name = 'Assign Via Nets from Nearest Copper'
		self.category = 'Placement'
		self.description = 'Update net assignment of all selected vias to match the nearest copper item'
		self.show_toolbar_button = True
		self.icon_file_name = ''

	def Run(self):
		try:
			board = pcbnew.GetBoard()
			count, err = assign_via_nets(board)
			if err:
				wx.MessageBox(err, 'Via Net Assign', wx.OK | wx.ICON_INFORMATION)
			else:
				wx.MessageBox(f'{count} via(s) updated.', 'Via Net Assign', wx.OK | wx.ICON_INFORMATION)
		except Exception:
			msg = traceback.format_exc()
			dlg = wx.Dialog(None, title='Via Net Assign — Error', size=(520, 320),
			                style=wx.DEFAULT_DIALOG_STYLE | wx.RESIZE_BORDER)
			s = wx.BoxSizer(wx.VERTICAL)
			txt = wx.TextCtrl(dlg, value=msg, style=wx.TE_MULTILINE | wx.TE_READONLY | wx.HSCROLL)
			txt.SetFont(wx.Font(9, wx.FONTFAMILY_TELETYPE, wx.FONTSTYLE_NORMAL, wx.FONTWEIGHT_NORMAL))
			s.Add(txt, 1, wx.EXPAND | wx.ALL, 6)
			btn = wx.Button(dlg, wx.ID_CLOSE, 'Close')
			btn.Bind(wx.EVT_BUTTON, lambda e: dlg.Close())
			s.Add(btn, 0, wx.ALIGN_RIGHT | wx.ALL, 6)
			dlg.SetSizer(s)
			dlg.ShowModal()
			dlg.Destroy()