#!/usr/bin/env python3
"""
Cross-platform hash comparison for determinism verification.
Sprint: SPRINT_20251226_007_BE_determinism_gaps
Task: DET-GAP-13 - Cross-platform hash comparison report generation
"""

import argparse
import json
import sys
from datetime import datetime, timezone
from pathlib import Path
from typing import Any


def load_hashes(path: str) -> dict[str, str]:
    """Load hash file from path."""
    with open(path) as f:
        data = json.load(f)
    return data.get("hashes", data)


def compare_hashes(
    linux: dict[str, str],
    windows: dict[str, str],
    macos: dict[str, str]
) -> tuple[list[dict], list[str]]:
    """
    Compare hashes across platforms.
    Returns (divergences, matched_keys).
    """
    all_keys = set(linux.keys()) | set(windows.keys()) | set(macos.keys())
    divergences = []
    matched = []

    for key in sorted(all_keys):
        linux_hash = linux.get(key, "MISSING")
        windows_hash = windows.get(key, "MISSING")
        macos_hash = macos.get(key, "MISSING")

        if linux_hash == windows_hash == macos_hash:
            matched.append(key)
        else:
            divergences.append({
                "key": key,
                "linux": linux_hash,
                "windows": windows_hash,
                "macos": macos_hash
            })

    return divergences, matched


def generate_markdown_report(
    divergences: list[dict],
    matched: list[str],
    linux_path: str,
    windows_path: str,
    macos_path: str
) -> str:
    """Generate Markdown report."""
    lines = [
        f"**Generated:** {datetime.now(timezone.utc).isoformat()}",
        "",
        "### Summary",
        "",
        f"- ✅ **Matched:** {len(matched)} hashes",
        f"- {'❌' if divergences else '✅'} **Divergences:** {len(divergences)} hashes",
        "",
    ]

    if divergences:
        lines.extend([
            "### Divergences",
            "",
            "| Key | Linux | Windows | macOS |",
            "|-----|-------|---------|-------|",
        ])
        for d in divergences:
            linux_short = d["linux"][:16] + "..." if len(d["linux"]) > 16 else d["linux"]
            windows_short = d["windows"][:16] + "..." if len(d["windows"]) > 16 else d["windows"]
            macos_short = d["macos"][:16] + "..." if len(d["macos"]) > 16 else d["macos"]
            lines.append(f"| `{d['key']}` | `{linux_short}` | `{windows_short}` | `{macos_short}` |")
        lines.append("")

    lines.extend([
        "### Matched Hashes",
        "",
        f"<details><summary>Show {len(matched)} matched hashes</summary>",
        "",
    ])
    for key in matched[:50]:  # Limit display
        lines.append(f"- `{key}`")
    if len(matched) > 50:
        lines.append(f"- ... and {len(matched) - 50} more")
    lines.extend(["", "</details>", ""])

    return "\n".join(lines)


def main():
    parser = argparse.ArgumentParser(description="Compare determinism hashes across platforms")
    parser.add_argument("--linux", required=True, help="Path to Linux hashes JSON")
    parser.add_argument("--windows", required=True, help="Path to Windows hashes JSON")
    parser.add_argument("--macos", required=True, help="Path to macOS hashes JSON")
    parser.add_argument("--output", required=True, help="Output JSON report path")
    parser.add_argument("--markdown", required=True, help="Output Markdown report path")
    args = parser.parse_args()

    # Load hashes
    linux_hashes = load_hashes(args.linux)
    windows_hashes = load_hashes(args.windows)
    macos_hashes = load_hashes(args.macos)

    # Compare
    divergences, matched = compare_hashes(linux_hashes, windows_hashes, macos_hashes)

    # Generate reports
    report = {
        "timestamp": datetime.now(timezone.utc).isoformat(),
        "sources": {
            "linux": args.linux,
            "windows": args.windows,
            "macos": args.macos
        },
        "summary": {
            "matched": len(matched),
            "divergences": len(divergences),
            "total": len(matched) + len(divergences)
        },
        "divergences": divergences,
        "matched": matched
    }

    # Write JSON report
    Path(args.output).parent.mkdir(parents=True, exist_ok=True)
    with open(args.output, "w") as f:
        json.dump(report, f, indent=2)

    # Write Markdown report
    markdown = generate_markdown_report(
        divergences, matched,
        args.linux, args.windows, args.macos
    )
    with open(args.markdown, "w") as f:
        f.write(markdown)

    # Print summary
    print(f"Comparison complete:")
    print(f"  Matched: {len(matched)}")
    print(f"  Divergences: {len(divergences)}")

    # Exit with error if divergences found
    if divergences:
        print("\nERROR: Hash divergences detected!")
        sys.exit(1)


if __name__ == "__main__":
    main()