# backend/thumbnails.py
import wx
import pcbnew
from .resolvers import find_item_by_uuid

class ThumbnailGenerator:
    @staticmethod
    def generate_thumbnail(item_list, board, width=80, height=40):
        """
        Generates a simple preview bitmap of the items.
        """
        bmp = wx.Bitmap(width, height)
        dc = wx.MemoryDC(bmp)
        
        # Background
        dc.SetBackground(wx.Brush(wx.Colour(30, 30, 30)))
        dc.Clear()
        
        # Collect items
        items = []
        min_x, min_y = float('inf'), float('inf')
        max_x, max_y = float('-inf'), float('-inf')
        has_items = False
        
        for entry in item_list:
            uuid = entry['uuid']
            item = find_item_by_uuid(board, uuid)
            if item:
                items.append(item)
                bb = item.GetBoundingBox()
                min_x = min(min_x, bb.GetX())
                min_y = min(min_y, bb.GetY())
                max_x = max(max_x, bb.GetRight())
                max_y = max(max_y, bb.GetBottom())
                has_items = True
        
        if has_items:
            content_w = max_x - min_x
            content_h = max_y - min_y
            if content_w == 0: content_w = 1
            if content_h == 0: content_h = 1
            
            # Scale to fit in width x height with some padding
            scale_x = (width * 0.9) / content_w
            scale_y = (height * 0.9) / content_h
            scale = min(scale_x, scale_y)
            
            off_x = (width - (content_w * scale)) / 2
            off_y = (height - (content_h * scale)) / 2
            
            pen_track = wx.Pen(wx.Colour(0, 200, 0), 1)
            brush_pad = wx.Brush(wx.Colour(200, 0, 0))
            pen_pad = wx.Pen(wx.Colour(200, 0, 0), 1)
            
            for item in items:
                cls = item.GetClass()
                if cls == "PCB_TRACK":
                    dc.SetPen(pen_track)
                    t = pcbnew.Cast_to_PCB_TRACK(item)
                    start = t.GetStart()
                    end = t.GetEnd()
                    x1 = int((start.x - min_x) * scale + off_x)
                    y1 = int((start.y - min_y) * scale + off_y)
                    x2 = int((end.x - min_x) * scale + off_x)
                    y2 = int((end.y - min_y) * scale + off_y)
                    dc.DrawLine(x1, y1, x2, y2)
                elif cls == "PCB_VIA":
                    dc.SetPen(pen_track)
                    dc.SetBrush(wx.Brush(wx.Colour(200, 200, 0)))
                    v = pcbnew.Cast_to_PCB_VIA(item)
                    pos = v.GetPosition()
                    x = int((pos.x - min_x) * scale + off_x)
                    y = int((pos.y - min_y) * scale + off_y)
                    r = max(1, int((v.GetWidth() / 2) * scale))
                    dc.DrawCircle(x, y, r)
                else:
                    dc.SetPen(pen_pad)
                    dc.SetBrush(brush_pad)
                    bb = item.GetBoundingBox()
                    x = int((bb.GetX() - min_x) * scale + off_x)
                    y = int((bb.GetY() - min_y) * scale + off_y)
                    w = int(bb.GetWidth() * scale)
                    h = int(bb.GetHeight() * scale)
                    if w < 2: w = 2
                    if h < 2: h = 2
                    dc.DrawRectangle(x, y, w, h)
        
        dc.SelectObject(wx.NullBitmap)
        return bmp