"""
Compare original Dropbox folder with recovery folder — file by file.

Checks:
  1. Files in original but missing in recovery
  2. Files in recovery but missing in original
  3. Size mismatches
  4. Content mismatches (BLAKE3 hash)

Usage: python compare_recovery.py
"""

import os
import sys
import time
from indexer.config import ROOT_PATH
from indexer.hasher import blake3_file

RECOVERY_DIR = r"U:\recovery"


def scan_dir(root: str) -> dict:
    """Walk directory, return {relative_path: {size, full_path}}."""
    result = {}
    for dirpath, _dirs, files in os.walk(root):
        for fn in files:
            full = os.path.join(dirpath, fn)
            try:
                size = os.path.getsize(full)
            except (OSError, PermissionError):
                continue
            rel = os.path.relpath(full, root).replace("\\", "/")
            result[rel] = {"size": size, "full_path": full}
    return result


def main():
    original_dir = ROOT_PATH.rstrip("\\/")
    recovery_dir = RECOVERY_DIR.rstrip("\\/")

    print("=" * 70)
    print("COMPARE: Original vs Recovery")
    print(f"  Original : {original_dir}")
    print(f"  Recovery : {recovery_dir}")
    print("=" * 70)

    if not os.path.isdir(original_dir):
        print(f"ERROR: Original dir not found: {original_dir}")
        sys.exit(1)
    if not os.path.isdir(recovery_dir):
        print(f"ERROR: Recovery dir not found: {recovery_dir}")
        sys.exit(1)

    # ── 1. Scan both directories ──
    print("\n[1/3] Scanning original...")
    orig = scan_dir(original_dir)
    print(f"       {len(orig)} files")

    print("[2/3] Scanning recovery...")
    recov = scan_dir(recovery_dir)
    print(f"       {len(recov)} files")

    orig_paths = set(orig.keys())
    recov_paths = set(recov.keys())

    missing_in_recovery = sorted(orig_paths - recov_paths)
    extra_in_recovery = sorted(recov_paths - orig_paths)
    common = sorted(orig_paths & recov_paths)

    # ── 2. Report missing / extra ──
    print(f"\n{'='*70}")
    print(f"  Common files          : {len(common)}")
    print(f"  Missing in recovery   : {len(missing_in_recovery)}")
    print(f"  Extra in recovery     : {len(extra_in_recovery)}")
    print(f"{'='*70}")

    if missing_in_recovery:
        print(f"\n--- Missing in recovery ({len(missing_in_recovery)}) ---")
        for p in missing_in_recovery[:50]:
            print(f"  {p}  ({orig[p]['size']} bytes)")
        if len(missing_in_recovery) > 50:
            print(f"  ... and {len(missing_in_recovery) - 50} more")

    if extra_in_recovery:
        print(f"\n--- Extra in recovery ({len(extra_in_recovery)}) ---")
        for p in extra_in_recovery[:50]:
            print(f"  {p}  ({recov[p]['size']} bytes)")
        if len(extra_in_recovery) > 50:
            print(f"  ... and {len(extra_in_recovery) - 50} more")

    # ── 3. Compare common files: size + hash ──
    print(f"\n[3/3] Comparing {len(common)} common files (size + BLAKE3)...")
    size_mismatch = []
    hash_mismatch = []
    hash_ok = 0
    errors = 0
    start = time.time()

    for i, p in enumerate(common, 1):
        o = orig[p]
        r = recov[p]

        if o["size"] != r["size"]:
            size_mismatch.append((p, o["size"], r["size"]))
            continue

        # Same size → compare BLAKE3 hash
        try:
            h_orig = blake3_file(o["full_path"])
            h_recov = blake3_file(r["full_path"])
        except Exception as e:
            errors += 1
            print(f"  ERROR hashing {p}: {e}")
            continue

        if h_orig != h_recov:
            hash_mismatch.append(p)
        else:
            hash_ok += 1

        if i % 2000 == 0:
            elapsed = time.time() - start
            print(f"  [{i}/{len(common)}] ok={hash_ok} size_diff={len(size_mismatch)} "
                  f"hash_diff={len(hash_mismatch)} errors={errors} elapsed={elapsed:.0f}s")

    elapsed = time.time() - start

    # ── Summary ──
    print(f"\n{'='*70}")
    print(f"COMPARISON COMPLETE  ({elapsed:.0f}s)")
    print(f"{'='*70}")
    print(f"  Original files        : {len(orig)}")
    print(f"  Recovery files        : {len(recov)}")
    print(f"  Missing in recovery   : {len(missing_in_recovery)}")
    print(f"  Extra in recovery     : {len(extra_in_recovery)}")
    print(f"  Size matches + hash OK: {hash_ok}")
    print(f"  Size mismatches       : {len(size_mismatch)}")
    print(f"  Hash mismatches       : {len(hash_mismatch)}")
    print(f"  Errors                : {errors}")

    if size_mismatch:
        print(f"\n--- Size mismatches ({len(size_mismatch)}) ---")
        for p, os_, rs in size_mismatch[:20]:
            print(f"  {p}  orig={os_} recov={rs}")

    if hash_mismatch:
        print(f"\n--- Hash mismatches ({len(hash_mismatch)}) ---")
        for p in hash_mismatch[:20]:
            print(f"  {p}")

    if not missing_in_recovery and not extra_in_recovery and not size_mismatch and not hash_mismatch and errors == 0:
        print("\n✓ PERFECT MATCH — recovery is identical to original.")
    elif not size_mismatch and not hash_mismatch and errors == 0:
        print(f"\n✓ All {hash_ok} common files match. "
              f"({len(missing_in_recovery)} missing, {len(extra_in_recovery)} extra)")

    print(f"{'='*70}")


if __name__ == "__main__":
    main()