#!/usr/bin/env python3
"""Build the share index that the musician's /get_share_list endpoint searches.

Walks the media root and writes a JSON catalogue of every file/dir found.
Meant to run periodically (cron on bare metal, the scheduler loop in the share
container). Paths are environment-overridable; the defaults reproduce the
original Raspberry Pi layout, so existing cron entries keep working unchanged.
"""
import os
import json
import time

# Configuration (env-overridable; defaults = original bare-metal Pi layout)
SCAN_PATH = os.getenv('CONJURER_SHARE_SCAN_PATH', '/mnt/shares')
OUTPUT_FILE = os.getenv('CONJURER_SHARE_DB', '/var/log/share_scan.json')

def scan_directory(root):
    """Recursively walk `root` and collect metadata."""
    entries = []
    for dirpath, dirs, files in os.walk(root):
        for name in dirs + files:
            full = os.path.join(dirpath, name)
            try:
                stat = os.stat(full)
                entries.append({
                    'path': full,
                    'is_dir': os.path.isdir(full),
                    'size_bytes': stat.st_size,
                    'mtime': time.strftime('%Y-%m-%dT%H:%M:%S%z',
                                           time.localtime(stat.st_mtime)),
                })
            except Exception as e:
                # skip items we can't stat
                continue
    return entries

def main():
    data = {
        'scanned_at': time.strftime('%Y-%m-%dT%H:%M:%S%z', time.localtime()),
        'root': SCAN_PATH,
        'entries': scan_directory(SCAN_PATH),
    }
    # Write atomically (create the target dir first so a fresh volume works)
    os.makedirs(os.path.dirname(OUTPUT_FILE) or '.', exist_ok=True)
    temp = OUTPUT_FILE + '.tmp'
    with open(temp, 'w') as f:
        json.dump(data, f, indent=2)
    os.replace(temp, OUTPUT_FILE)

if __name__ == '__main__':
    main()