"""
UICopilot CLI — analyze a screenshot or HTML file from the command line.

Usage:
  python backend/cli.py check screenshot.png
  python backend/cli.py check page.html --threshold 60
  python backend/cli.py check screenshot.png --format json --out report.json
  python backend/cli.py check screenshot.png --device mobile --no-attention

Exit codes:
  0 — score >= threshold (PASS)
  1 — score < threshold (FAIL)
  2 — input error / file not found
"""
from __future__ import annotations

import argparse
import json
import pathlib
import sys

if sys.stdout.encoding and sys.stdout.encoding.lower() not in ("utf-8", "utf-16"):
    sys.stdout.reconfigure(encoding="utf-8", errors="replace")

_IMAGE_EXTS = {".png", ".jpg", ".jpeg", ".webp", ".gif", ".bmp"}
_HTML_EXTS = {".html", ".htm"}


def _die(msg: str, code: int = 2) -> None:
    print(f"ERROR: {msg}", file=sys.stderr)
    sys.exit(code)


def _build_parser() -> argparse.ArgumentParser:
    ap = argparse.ArgumentParser(
        prog="uicopilot",
        description="UICopilot — UI quality analysis from the command line",
    )
    sub = ap.add_subparsers(dest="cmd", metavar="COMMAND")

    ck = sub.add_parser("check", help="Analyze a file and exit non-zero if score < threshold")
    ck.add_argument("file", help="Screenshot (PNG/JPG/WebP) or HTML file to analyze")
    ck.add_argument("--threshold", type=int, default=70,
                    help="Minimum passing score, 0-100 (default: 70)")
    ck.add_argument("--format", choices=["text", "json"], default="text",
                    help="Output format (default: text)")
    ck.add_argument("--out", metavar="FILE",
                    help="Write JSON report to this file (in addition to stdout)")
    ck.add_argument("--device", choices=["auto", "mobile", "desktop"], default="auto",
                    help="Device type hint for screenshots (default: auto)")
    ck.add_argument("--no-attention", action="store_true",
                    help="Skip attention heatmap computation (faster)")
    return ap


def _analyze(path: pathlib.Path, device: str, include_attention: bool) -> dict:
    from backend.analyzers import html_analyzer, screenshot_analyzer
    from backend.services import attention_service, scoring_engine

    ext = path.suffix.lower()
    if ext in _HTML_EXTS:
        html = path.read_text(encoding="utf-8", errors="replace")
        parsed = html_analyzer.parse(html)
        image_bytes = None
    elif ext in _IMAGE_EXTS:
        image_bytes = path.read_bytes()
        parsed = screenshot_analyzer.analyze(image_bytes, device_hint=device)
    else:
        _die(f"Unsupported file type '{ext}'. Use {sorted(_IMAGE_EXTS | _HTML_EXTS)}")

    result = scoring_engine.analyze(parsed)

    out: dict = {
        "file": str(path),
        "score": round(result.overall_score, 1),
        "issue_count": len(result.issues),
        "category_scores": {
            cs.category.value: round(cs.score, 1)
            for cs in result.category_scores
        },
        "top_issues": [
            {
                "rule_id": i.rule_id,
                "severity": i.severity.value,
                "message": i.message,
                "gain": round(i.estimated_gain, 1),
                "time": i.estimated_time,
            }
            for i in result.top_issues[:5]
        ],
        "quick_wins": [
            {"rule_id": i.rule_id, "message": i.message, "gain": round(i.estimated_gain, 1)}
            for i in result.quick_wins[:3]
        ],
    }

    if include_attention and image_bytes is not None:
        attn = attention_service.analyze(image_bytes)
        out["focus_score"] = attn["focus_score"]
        out["attention_regions"] = len(attn.get("top_regions", []))

    return out


def _print_text(out: dict, threshold: int) -> None:
    score = out["score"]
    passed = score >= threshold
    status = "PASS" if passed else "FAIL"
    mark = "+" if passed else "-"

    print(f"\nUICopilot  {out['file']}")
    print("─" * 52)
    print(f"  Score      {score}/100   (threshold: {threshold})   [{status}]")
    print(f"  Issues     {out['issue_count']}")
    if "focus_score" in out:
        print(f"  Focus      {out['focus_score']}/100")

    if out["top_issues"]:
        print("\n  Top issues:")
        for i in out["top_issues"]:
            sev = i["severity"].upper()
            print(f"    [{sev:<8}] +{i['gain']:.1f}pt  {i['message']}")

    if out["quick_wins"]:
        print("\n  Quick wins (fix first):")
        for w in out["quick_wins"]:
            print(f"    +{w['gain']:.1f}pt  {w['message']}")

    print("\n  Category scores:")
    for cat, s in sorted(out["category_scores"].items(), key=lambda x: x[1]):
        bar = int(s / 5)
        print(f"    {cat.replace('_',' '):<24} {'█'*bar}{'░'*(20-bar)} {s}")

    print(f"\n  {mark * 3} {status} — {score}/100 (threshold {threshold}) {mark * 3}\n")


def cmd_check(args: argparse.Namespace) -> None:
    path = pathlib.Path(args.file)
    if not path.exists():
        _die(f"File not found: {path}")

    include_attention = not args.no_attention
    out = _analyze(path, args.device, include_attention)
    out["threshold"] = args.threshold
    out["passed"] = out["score"] >= args.threshold

    if args.out:
        pathlib.Path(args.out).write_text(
            json.dumps(out, indent=2), encoding="utf-8"
        )

    if args.format == "json":
        print(json.dumps(out, indent=2))
    else:
        _print_text(out, args.threshold)

    sys.exit(0 if out["passed"] else 1)


def main() -> None:
    ap = _build_parser()
    args = ap.parse_args()
    if args.cmd == "check":
        cmd_check(args)
    else:
        ap.print_help()
        sys.exit(2)


if __name__ == "__main__":
    main()