"""
Step 1: Scan a restored FCCS backup directory for drawer IDs.

Every subdirectory in the backup root corresponds to a drawer.
Writes the sorted list of drawer IDs to the configured drawer_id_file.
"""

import os
import sys

from fccs_config import (
    parse_args, load_config, make_logger, load_lines, check_for_clashes,
)


_IGNORE_HEADER = [
    "# Drawer IDs to SKIP during export (one ID per line).",
    "# Lines starting with # are comments and are ignored.",
    "#",
    "# Add password-protected or otherwise-excluded drawers here.",
    "#",
    "# The IDs auto-added below are prefix clashes: searching the base ID in",
    "# FCCS pops a selection box that breaks the plain export. Only the base",
    "# (shorter) ID is listed — the longer, more-specific IDs export normally.",
    "# The base IDs are exported separately by fccs_export_clashes.py, which",
    "# handles the selection box. DELETE or comment out any you'd rather skip.",
    "",
]


def update_ignore_file(ignore_file, clashes, log):
    """Create ignore.txt if missing and seed it with clash base (prefix) IDs.

    Only the shorter (prefix) ID of each clash is added — that's the one that
    triggers the FCCS selection box and needs special handling. The longer,
    more-specific IDs (e.g. '02218A') search fine and export normally.
    Never overwrites existing entries — only appends prefixes not already
    present. Returns the list of IDs added.
    """
    existing = set(load_lines(ignore_file))
    file_exists = os.path.exists(ignore_file)

    to_add = [(short, matches) for short, matches in clashes
              if short not in existing]

    # Existing file already covers every clash — leave it untouched.
    if file_exists and not to_add:
        return []

    lines = []
    if not file_exists:
        lines.extend(_IGNORE_HEADER)
    for short, matches in to_add:
        lines.append(f"# clashes with: {', '.join(matches)}")
        lines.append(short)

    mode = "a" if file_exists else "w"
    with open(ignore_file, mode, encoding="utf-8") as f:
        if file_exists:
            f.write("\n")  # separate the new block from prior content
        f.write("\n".join(lines) + "\n")

    added = [short for short, _ in to_add]
    if not file_exists:
        log(f"Created ignore file: {ignore_file}")
    if added:
        log(f"Added {len(added)} clash base ID(s) to ignore list: "
            f"{', '.join(added)}")
    return added


def main():
    args = parse_args()
    cfg = load_config(args.config)
    log = make_logger(cfg.get("paths", "log_file"))

    backup_dir = cfg.get("paths", "backup_dir")
    output_file = cfg.get("paths", "drawer_id_file")
    ignore_file = cfg.get("paths", "ignore_file")

    if not os.path.isdir(backup_dir):
        log(f"ERROR: backup directory not found: {backup_dir}")
        sys.exit(1)

    # Only subdirectories are drawers. When pointed at FCCS's live data dir
    # (e.g. the Restore directory) there are also system folders that start with
    # "$" and miscellaneous loose files — skip both. The isdir check drops the
    # files; the "$" prefix check drops the system folders.
    drawer_ids = sorted(
        name for name in os.listdir(backup_dir)
        if not name.startswith("$")
        and os.path.isdir(os.path.join(backup_dir, name))
    )

    with open(output_file, "w", encoding="utf-8") as f:
        for did in drawer_ids:
            f.write(did + "\n")

    log(f"Found {len(drawer_ids)} drawers, written to {output_file}")

    # Flag prefix clashes: FCCS search on the shorter ID pops a selection box.
    clashes = check_for_clashes(drawer_ids)
    if clashes:
        log("-" * 60)
        log(f"WARNING: {len(clashes)} potential drawer ID clash(es) found.")
        log("Searching the shorter ID in FCCS may show a selection box "
            "instead of navigating directly, which breaks the export.")
        for short, matches in clashes:
            log(f"  {short}  ->  also matches: {', '.join(matches)}")
        # Seed ignore.txt with the clash prefixes for review (never overwrites).
        update_ignore_file(ignore_file, clashes, log)
        log(f"Review the ignore list: {ignore_file}")
        log("-" * 60)
    else:
        log("No drawer ID prefix clashes found.")

    # Report which drawers will be skipped by the export.
    ignored = set(load_lines(ignore_file))
    if ignored:
        present = sorted(ignored & set(drawer_ids))
        log(f"Ignore list ({ignore_file}): {len(ignored)} IDs listed, "
            f"{len(present)} present in this backup — these will be SKIPPED "
            f"by fccs_export.py: {', '.join(present) if present else '(none present)'}")


if __name__ == "__main__":
    main()