#!/usr/bin/env python3
"""Render actual SchDoc and compare to a trusted Altium page PNG, without alignment.

Images must represent the same sheet viewport. No registration, recoloring or
cropping hides coordinate differences. Altium PDF exports can be rasterized to
PNG with pdftoppm first. This tool does not manufacture reference images.
"""
import argparse
import hashlib
import json
import sys
from pathlib import Path
sys.path.insert(0,str(Path(__file__).resolve().parents[1]/'backend'))
import cairosvg
import numpy as np
from PIL import Image
from app.parser.schdoc_parser import parse_schdoc
from app.render import svg_document


def main():
    p=argparse.ArgumentParser(description=__doc__)
    p.add_argument('schematic',type=Path)
    p.add_argument('--reference',type=Path)
    p.add_argument('--output',type=Path,default=Path('validation-output'))
    p.add_argument('--width',type=int,default=2000)
    p.add_argument('--max-mae',type=float,default=2.0,help='Mean absolute RGB error threshold, 0..255')
    p.add_argument('--max-changed-fraction',type=float,default=.01)
    p.add_argument('--pixel-tolerance',type=int,default=12)
    args=p.parse_args(); args.output.mkdir(parents=True,exist_ok=True)
    raw=args.schematic.read_bytes(); doc=parse_schdoc(raw,args.schematic.name,'validation')
    svg=svg_document(doc); (args.output/'drawing.svg').write_bytes(svg)
    width=args.width; height=max(1,round(width*doc.sheet.bounds.height/doc.sheet.bounds.width))
    if args.reference:
        with Image.open(args.reference) as ref: width,height=ref.size
        expected_ratio=doc.sheet.bounds.width/doc.sheet.bounds.height
        if abs(width/height/expected_ratio-1)>.005:
            p.error('Reference aspect ratio differs from original sheet; export the same viewport')
    png=cairosvg.svg2png(bytestring=svg,output_width=width,output_height=height)
    (args.output/'rendered.png').write_bytes(png)
    report={'source_sha256':hashlib.sha256(raw).hexdigest(),'record_count':doc.metadata['record_count'],
            'component_count':len(doc.components),'primitive_count':len(doc.primitives),
            'diagnostics':[d.model_dump() for d in doc.diagnostics],
            'reference_compared':bool(args.reference),'fidelity_verified':False}
    passed=True
    if args.reference:
        reference=Image.open(args.reference).convert('RGB'); actual=Image.open(args.output/'rendered.png').convert('RGB')
        a=np.array(actual,dtype=np.int16); b=np.array(reference,dtype=np.int16); delta=np.abs(a-b)
        mae=float(delta.mean()); changed=float((delta.max(axis=2)>args.pixel_tolerance).mean())
        heat=np.zeros_like(a,dtype=np.uint8); heat[:,:,0]=np.clip(delta.max(axis=2)*4,0,255).astype(np.uint8)
        Image.fromarray(heat).save(args.output/'difference.png')
        Image.blend(reference,actual,.5).save(args.output/'overlay.png')
        passed=mae<=args.max_mae and changed<=args.max_changed_fraction
        report.update(reference_sha256=hashlib.sha256(args.reference.read_bytes()).hexdigest(),mae=mae,
                      changed_pixel_fraction=changed,thresholds={'max_mae':args.max_mae,'max_changed_fraction':args.max_changed_fraction,'pixel_tolerance':args.pixel_tolerance},
                      regression_passed=passed)
    (args.output/'report.json').write_text(json.dumps(report,indent=2))
    print(json.dumps({k:v for k,v in report.items() if k!='diagnostics'},indent=2))
    return 0 if passed else 1

if __name__=='__main__': sys.exit(main())