import json
import os
from datetime import datetime, timezone
import config_utils
import factory

DNS_LOG_FILE = f'{config_utils.CONFIGS_DIR}/dns-blocklists.log'
DNS_LOG_MAX  = 50

BL_TYPE_LABELS = {'community': 'Community', 'local': 'Local'}


def _dnsblocking_log_tail(cfg):
    try:
        log_max_kb = cfg.get('dns_blocking', {}).get('general', {}).get('log_max_kb', 1024)
        size_kb = os.path.getsize(DNS_LOG_FILE) / 1024
        with open(DNS_LOG_FILE) as f:
            lines = f.readlines()
        if not lines:
            return '(log is empty)', ''
        total  = len(lines)
        tail   = lines[-DNS_LOG_MAX:]
        shown  = len(tail)
        hidden = total - shown
        pct    = min(100, round(size_kb / log_max_kb * 100)) if log_max_kb else 0
        left   = f'Showing {shown} of {total} lines ({hidden} not shown)' if hidden > 0 else f'Showing {shown} of {total} lines'
        right  = f'Log file size: {size_kb:.1f} KB ({pct}% of max)'
        summary = (
            '<div class="text-muted" style="display:flex;justify-content:space-between;margin-top:0.5em;">'
            f'<span>{left}</span><span>{right}</span></div>'
        )
        return ''.join(tail).strip(), summary
    except FileNotFoundError:
        return '(log file not found)', ''
    except Exception:
        return '(error reading log)', ''


def blocklist_stats_html(cfg):
    rows = ''
    for bl in cfg.get('dns_blocking', {}).get('blocklists', []):
        name    = factory.e(bl.get('name', ''))
        is_local = bl.get('bl_type') == 'local'
        save_as = bl.get('save_as', '')
        bl_path = f'{config_utils.BLOCKLISTS_DIR}/{save_as}' if save_as else ''
        if is_local:
            try:
                with open(bl_path) as f:
                    entries = sum(1 for ln in f if ln.strip() and not ln.startswith('#'))
                size_str = config_utils.fmt_bytes(os.path.getsize(bl_path))
                last_refreshed = 'Local'
            except Exception:
                entries, size_str, last_refreshed = '-', '-', 'Local'
        else:
            try:
                with open(bl_path) as f:
                    entries = sum(1 for _ in f)
                mtime = int(os.path.getmtime(bl_path))
                size_str = config_utils.fmt_bytes(os.path.getsize(bl_path))
                last_refreshed = (
                    f'{datetime.fromtimestamp(mtime).strftime("%Y-%m-%d %H:%M")}'
                    f' ({config_utils.relative_time(mtime, datetime.now(tz=timezone.utc).timestamp())} ago)'
                )
            except Exception:
                entries, size_str, last_refreshed = '-', '-', 'Never'
        rows += (
            '<tr>'
            f'<td class="table-cell">{name}</td>'
            f'<td class="table-cell">{entries}</td>'
            f'<td class="table-cell">{size_str}</td>'
            f'<td class="table-cell">{factory.e(last_refreshed)}</td>'
            '</tr>'
        )
    if not rows:
        return ''
    return (
        '<table class="data-table"><thead><tr>'
        '<th class="table-header">Blocklist</th>'
        '<th class="table-header">Entries</th>'
        '<th class="table-header">Size</th>'
        '<th class="table-header">Last Refreshed</th>'
        '</tr></thead>'
        f'<tbody>{rows}</tbody></table>'
    )


def collect_tokens(cfg):
    tokens = config_utils.collect_layout_tokens(cfg)
    dns_blk_gen = cfg.get('dns_blocking', {}).get('general', {})
    tokens['GENERAL_LOG_MAX_KB']         = str(dns_blk_gen.get('log_max_kb', '-'))
    tokens['GENERAL_LOG_ERRORS_ONLY']    = 'true' if dns_blk_gen.get('log_errors_only') else 'false'
    tokens['GENERAL_DAILY_EXECUTE_TIME'] = str(dns_blk_gen.get('daily_execute_time_24hr_local', '-'))
    tokens['BLOCKLIST_STATS_HTML']       = blocklist_stats_html(cfg)
    tokens['DNS_LOG_TAIL'], tokens['DNS_LOG_SUMMARY'] = _dnsblocking_log_tail(cfg)
    blocklists = cfg.get('dns_blocking', {}).get('blocklists', [])
    tokens['BLOCKLIST_EXISTING_NAMES_JS'] = json.dumps([bl.get('name', '') for bl in blocklists])
    content = factory.load_json(f'{factory.PAGES_DIR}/dnsblocking/content.json')
    for table_item in factory.iter_table_items(content.get('items', [])):
        ds = table_item.get('datasource', '')
        tokens[factory.table_token_key(ds)] = factory.build_table(table_item, tokens, config_utils.load_datasource(ds))
    return tokens