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):
    db_rows = config_utils._bl_db_rows()
    rows = ''
    for bl in cfg.get('dns_blocking', {}).get('blocklists', []):
        name     = bl.get('name', '')
        is_local = bl.get('bl_type') == 'local'
        db       = db_rows.get(name, {})
        count    = db.get('domain_count')
        entries  = f'{count:,}' if count is not None else '-'
        if is_local:
            save_as  = bl.get('save_as', '')
            bl_path  = f'{config_utils.BLOCKLISTS_DIR}/{save_as}' if save_as else ''
            try:
                size_str = config_utils.fmt_bytes(os.path.getsize(bl_path))
            except Exception:
                size_str = '-'
            last_refreshed = 'Local'
        else:
            fetched_at = db.get('fetched_at')
            if fetched_at:
                last_refreshed = (
                    f'{datetime.fromtimestamp(fetched_at).strftime("%Y-%m-%d %H:%M")}'
                    f' ({config_utils.relative_time(fetched_at, datetime.now(tz=timezone.utc).timestamp())} ago)'
                )
            else:
                last_refreshed = 'Never'
            save_as = bl.get('save_as', '')
            bl_path = f'{config_utils.BLOCKLISTS_DIR}/{save_as}' if save_as else ''
            try:
                size_str = config_utils.fmt_bytes(os.path.getsize(bl_path))
            except Exception:
                size_str = '-'
        rows += (
            '<tr>'
            f'<td class="table-cell">{factory.e(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])
    vlans = cfg.get('vlans', [])
    vlan_checkboxes = ''.join(
        f'<label class="form-checkbox-row">'
        f'<input type="checkbox" name="used_by_vlans" value="{factory.e(v["name"])}" class="form-checkbox">'
        f' <span class="form-checkbox-label">{factory.e(v["name"])}</span>'
        f'</label>'
        for v in vlans if v.get('name')
    )
    tokens['VLAN_USED_BY_CHECKBOXES'] = (
        f'<div class="form-group"><label class="form-label">Used By VLAN(s)</label>'
        f'<div>{vlan_checkboxes}</div></div>'
    ) if vlan_checkboxes else ''
    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