# frozen_string_literal: true

require 'ostruct'

# EventDdb - DuckDB-backed analytics queries for events
# Provides an ActiveRecord-like interface for querying DuckDB events table
# Falls back to PostgreSQL Event model if DuckDB is unavailable
class EventDdb
  class << self
    # Get DuckDB service
    def service
      AnalyticsDuckdbService.instance
    end

    # Total events since timestamp
    def count_since(start_time)
      service.with_connection do |conn|
        result = conn.query("SELECT COUNT(*) as count FROM events WHERE timestamp >= ?", start_time)
        result.first&.first || 0
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in count_since: #{e.message}"
      nil # Fallback to PostgreSQL
    end

    # Event breakdown by WAF action
    def breakdown_by_action(start_time)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time)
          SELECT waf_action, COUNT(*) as count
          FROM events
          WHERE timestamp >= ?
          GROUP BY waf_action
        SQL

        # Convert to hash like ActiveRecord .group.count returns
        # DuckDB returns integer enum values, map to string names
        # 0=deny, 1=allow, 2=redirect, 3=challenge, 4=log
        action_map = { 0 => "deny", 1 => "allow", 2 => "redirect", 3 => "challenge", 4 => "log" }
        result.to_a.to_h { |row| [action_map[row[0]] || "unknown", row[1]] }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in breakdown_by_action: #{e.message}"
      nil
    end

    # Top countries with event counts
    def top_countries(start_time, limit = 10)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, limit)
          SELECT country, COUNT(*) as count
          FROM events
          WHERE timestamp >= ? AND country IS NOT NULL
          GROUP BY country
          ORDER BY count DESC
          LIMIT ?
        SQL

        # Return array of [country, count] tuples like ActiveRecord
        # DuckDB returns arrays: [country, count]
        result.to_a.map { |row| [row[0], row[1]] }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in top_countries: #{e.message}"
      nil
    end

    # Top blocked IPs
    def top_blocked_ips(start_time, limit = 10)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, limit)
          SELECT ip_address, COUNT(*) as count
          FROM events
          WHERE timestamp >= ? AND waf_action = 0
          GROUP BY ip_address
          ORDER BY count DESC
          LIMIT ?
        SQL

        # DuckDB returns arrays: [ip_address, count]
        result.to_a.map { |row| [row[0], row[1]] }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in top_blocked_ips: #{e.message}"
      nil
    end

    # Hourly timeline aggregation
    def hourly_timeline(start_time, end_time)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, end_time)
          SELECT
            DATE_TRUNC('hour', timestamp) as hour,
            COUNT(*) as count
          FROM events
          WHERE timestamp >= ? AND timestamp < ?
          GROUP BY hour
          ORDER BY hour
        SQL

        # Convert to hash with Time keys like ActiveRecord
        # DuckDB returns arrays: [hour, count]
        result.to_a.to_h { |row| [row[0], row[1]] }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in hourly_timeline: #{e.message}"
      nil
    end

    # Top networks by traffic volume
    # Returns array of arrays: [network_range_id, event_count, unique_ips]
    def top_networks(start_time, limit = 50)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, limit)
          SELECT
            network_range_id,
            COUNT(*) as event_count,
            COUNT(DISTINCT ip_address) as unique_ips
          FROM events
          WHERE timestamp >= ? AND network_range_id IS NOT NULL
          GROUP BY network_range_id
          ORDER BY event_count DESC
          LIMIT ?
        SQL

        result.to_a
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in top_networks: #{e.message}"
      nil
    end

    # Top companies
    # Returns array of OpenStruct objects with: company, event_count, unique_ips, network_count
    def top_companies(start_time, limit = 20)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, limit)
          SELECT
            company,
            COUNT(*) as event_count,
            COUNT(DISTINCT ip_address) as unique_ips,
            COUNT(DISTINCT network_range_id) as network_count
          FROM events
          WHERE timestamp >= ? AND company IS NOT NULL
          GROUP BY company
          ORDER BY event_count DESC
          LIMIT ?
        SQL

        # Convert arrays to OpenStruct for attribute access
        result.to_a.map do |row|
          OpenStruct.new(
            company: row[0],
            event_count: row[1],
            unique_ips: row[2],
            network_count: row[3]
          )
        end
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in top_companies: #{e.message}"
      nil
    end

    # Top ASNs
    # Returns array of OpenStruct objects with: asn, asn_org, event_count, unique_ips, network_count
    def top_asns(start_time, limit = 15)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, limit)
          SELECT
            asn,
            asn_org,
            COUNT(*) as event_count,
            COUNT(DISTINCT ip_address) as unique_ips,
            COUNT(DISTINCT network_range_id) as network_count
          FROM events
          WHERE timestamp >= ? AND asn IS NOT NULL
          GROUP BY asn, asn_org
          ORDER BY event_count DESC
          LIMIT ?
        SQL

        # Convert arrays to OpenStruct for attribute access
        result.to_a.map do |row|
          OpenStruct.new(
            asn: row[0],
            asn_org: row[1],
            event_count: row[2],
            unique_ips: row[3],
            network_count: row[4]
          )
        end
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in top_asns: #{e.message}"
      nil
    end

    # Network type breakdown (datacenter, VPN, proxy, standard)
    # Returns hash with network_type as key and hash of stats as value
    def network_type_breakdown(start_time)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time)
          SELECT
            CASE
              WHEN is_datacenter THEN 'datacenter'
              WHEN is_vpn THEN 'vpn'
              WHEN is_proxy THEN 'proxy'
              ELSE 'standard'
            END as network_type,
            COUNT(*) as event_count,
            COUNT(DISTINCT ip_address) as unique_ips,
            COUNT(DISTINCT network_range_id) as network_count
          FROM events
          WHERE timestamp >= ?
          GROUP BY network_type
        SQL

        # Convert arrays to hash: network_type => { event_count, unique_ips, network_count }
        result.to_a.to_h do |row|
          [
            row[0], # network_type
            {
              "event_count" => row[1],
              "unique_ips" => row[2],
              "network_count" => row[3]
            }
          ]
        end
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in network_type_breakdown: #{e.message}"
      nil
    end

    # Top countries with detailed stats (event count and unique IPs)
    # Returns array of OpenStruct objects with: country, event_count, unique_ips
    def top_countries_with_stats(start_time, limit = 15)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, limit)
          SELECT
            country,
            COUNT(*) as event_count,
            COUNT(DISTINCT ip_address) as unique_ips
          FROM events
          WHERE timestamp >= ? AND country IS NOT NULL
          GROUP BY country
          ORDER BY event_count DESC
          LIMIT ?
        SQL

        # Convert arrays to OpenStruct for attribute access
        result.to_a.map do |row|
          OpenStruct.new(
            country: row[0],
            event_count: row[1],
            unique_ips: row[2]
          )
        end
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in top_countries_with_stats: #{e.message}"
      nil
    end

    # Network type stats with formatted output matching controller expectations
    # Returns hash with type keys containing label, networks, events, unique_ips, percentage
    def network_type_stats(start_time)
      service.with_connection do |conn|
        # Get total events for percentage calculation
        total_result = conn.query("SELECT COUNT(*) as total FROM events WHERE timestamp >= ?", start_time)
        total_events = total_result.first&.first || 0

        # Get breakdown by network type
        breakdown = network_type_breakdown(start_time)
        return nil unless breakdown

        # Format results with labels and percentages
        results = {}

        {
          'datacenter' => 'Datacenter',
          'vpn' => 'VPN',
          'proxy' => 'Proxy',
          'standard' => 'Standard'
        }.each do |type, label|
          stats = breakdown[type]
          event_count = stats ? stats["event_count"] : 0

          results[type] = {
            label: label,
            networks: stats ? stats["network_count"] : 0,
            events: event_count,
            unique_ips: stats ? stats["unique_ips"] : 0,
            percentage: total_events > 0 ? ((event_count.to_f / total_events) * 100).round(1) : 0
          }
        end

        results
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in network_type_stats: #{e.message}"
      nil
    end

    # Network range traffic statistics
    # Returns comprehensive stats for a given network range ID(s)
    def network_traffic_stats(network_range_ids)
      network_range_ids = Array(network_range_ids)
      return nil if network_range_ids.empty?

      service.with_connection do |conn|
        # Build IN clause with placeholders
        placeholders = network_range_ids.map { "?" }.join(", ")

        # Get all stats in a single query
        result = conn.query(<<~SQL, *network_range_ids)
          SELECT
            COUNT(*) as total_requests,
            COUNT(DISTINCT ip_address) as unique_ips,
            SUM(CASE WHEN waf_action = 0 THEN 1 ELSE 0 END) as blocked_requests,
            SUM(CASE WHEN waf_action = 1 THEN 1 ELSE 0 END) as allowed_requests
          FROM events
          WHERE network_range_id IN (#{placeholders})
        SQL

        stats_row = result.first
        return nil unless stats_row

        {
          total_requests: stats_row[0] || 0,
          unique_ips: stats_row[1] || 0,
          blocked_requests: stats_row[2] || 0,
          allowed_requests: stats_row[3] || 0
        }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in network_traffic_stats: #{e.message}"
      nil
    end

    # Top paths for network range(s)
    def network_top_paths(network_range_ids, limit = 10)
      network_range_ids = Array(network_range_ids)
      return nil if network_range_ids.empty?

      service.with_connection do |conn|
        # Build IN clause with placeholders
        placeholders = network_range_ids.map { "?" }.join(", ")

        result = conn.query(<<~SQL, *network_range_ids, limit)
          SELECT
            request_path,
            COUNT(*) as count
          FROM events
          WHERE network_range_id IN (#{placeholders})
            AND request_path IS NOT NULL
          GROUP BY request_path
          ORDER BY count DESC
          LIMIT ?
        SQL

        result.to_a.map { |row| [row[0], row[1]] }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in network_top_paths: #{e.message}"
      nil
    end

    # Top user agents for network range(s)
    def network_top_user_agents(network_range_ids, limit = 5)
      network_range_ids = Array(network_range_ids)
      return nil if network_range_ids.empty?

      service.with_connection do |conn|
        # Build IN clause with placeholders
        placeholders = network_range_ids.map { "?" }.join(", ")

        result = conn.query(<<~SQL, *network_range_ids, limit)
          SELECT
            user_agent,
            COUNT(*) as count
          FROM events
          WHERE network_range_id IN (#{placeholders})
            AND user_agent IS NOT NULL
          GROUP BY user_agent
          ORDER BY count DESC
          LIMIT ?
        SQL

        result.to_a.map { |row| [row[0], row[1]] }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in network_top_user_agents: #{e.message}"
      nil
    end

    # Full user agent tally for network range(s)
    # Returns hash of user_agent => count for all agents in the network
    def network_agent_tally(network_range_ids)
      network_range_ids = Array(network_range_ids)
      return nil if network_range_ids.empty?

      service.with_connection do |conn|
        # Build IN clause with placeholders
        placeholders = network_range_ids.map { "?" }.join(", ")

        result = conn.query(<<~SQL, *network_range_ids)
          SELECT
            user_agent,
            COUNT(*) as count
          FROM events
          WHERE network_range_id IN (#{placeholders})
            AND user_agent IS NOT NULL
          GROUP BY user_agent
        SQL

        # Convert to hash matching Ruby .tally format
        result.to_a.to_h { |row| [row[0], row[1]] }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in network_agent_tally: #{e.message}"
      nil
    end

    # Suspicious network activity patterns
    # Detects high-volume networks, high deny rates, and distributed companies
    def suspicious_patterns(start_time)
      service.with_connection do |conn|
        # High volume networks (5x average)
        avg_query = conn.query(<<~SQL, start_time)
          SELECT
            AVG(event_count) as avg_events
          FROM (
            SELECT network_range_id, COUNT(*) as event_count
            FROM events
            WHERE timestamp >= ? AND network_range_id IS NOT NULL
            GROUP BY network_range_id
          ) network_stats
        SQL

        avg_events = avg_query.first&.first || 0
        threshold = avg_events * 5

        high_volume = conn.query(<<~SQL, start_time, threshold)
          SELECT
            network_range_id,
            COUNT(*) as event_count
          FROM events
          WHERE timestamp >= ? AND network_range_id IS NOT NULL
          GROUP BY network_range_id
          HAVING COUNT(*) > ?
          ORDER BY event_count DESC
        SQL

        # High deny rate networks (>50% blocked, min 10 requests)
        high_deny = conn.query(<<~SQL, start_time)
          SELECT
            network_range_id,
            SUM(CASE WHEN waf_action = 0 THEN 1 ELSE 0 END) as denied_count,
            COUNT(*) as total_count
          FROM events
          WHERE timestamp >= ? AND network_range_id IS NOT NULL
          GROUP BY network_range_id
          HAVING CAST(SUM(CASE WHEN waf_action = 0 THEN 1 ELSE 0 END) AS FLOAT) / COUNT(*) > 0.5
            AND COUNT(*) >= 10
          ORDER BY denied_count DESC
        SQL

        # Distributed companies (appearing with 5+ unique IPs)
        distributed_companies = conn.query(<<~SQL, start_time)
          SELECT
            company,
            COUNT(DISTINCT ip_address) as ip_count
          FROM events
          WHERE timestamp >= ? AND company IS NOT NULL
          GROUP BY company
          HAVING COUNT(DISTINCT ip_address) > 5
          ORDER BY ip_count DESC
          LIMIT 10
        SQL

        {
          high_volume: {
            count: high_volume.to_a.length,
            networks: high_volume.to_a.map { |row| row[0] } # network_range_id
          },
          high_deny_rate: {
            count: high_deny.to_a.length,
            network_ids: high_deny.to_a.map { |row| row[0] } # network_range_id
          },
          distributed_companies: distributed_companies.to_a.map { |row|
            {
              company: row[0], # company name
              subnets: row[1]  # ip_count
            }
          }
        }
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in suspicious_patterns: #{e.message}"
      nil
    end

    # Bot traffic analysis - breakdown of bot vs human traffic
    def bot_traffic_breakdown(start_time)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time)
          SELECT
            is_bot,
            COUNT(*) as event_count,
            COUNT(DISTINCT ip_address) as unique_ips
          FROM events
          WHERE timestamp >= ?
          GROUP BY is_bot
        SQL

        # Convert to hash: is_bot => { event_count, unique_ips }
        # DuckDB returns arrays: [is_bot, event_count, unique_ips]
        result.to_a.to_h do |row|
          [
            row[0] ? "bot" : "human",  # row[0] = is_bot
            {
              "event_count" => row[1],  # row[1] = event_count
              "unique_ips" => row[2]    # row[2] = unique_ips
            }
          ]
        end
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in bot_traffic_breakdown: #{e.message}"
      nil
    end

    # Count human traffic (non-bot) since timestamp
    def human_traffic_count(start_time)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time)
          SELECT COUNT(*) as count
          FROM events
          WHERE timestamp >= ? AND is_bot = false
        SQL

        result.first&.first || 0
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in human_traffic_count: #{e.message}"
      nil
    end

    # Count bot traffic since timestamp
    def bot_traffic_count(start_time)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time)
          SELECT COUNT(*) as count
          FROM events
          WHERE timestamp >= ? AND is_bot = true
        SQL

        result.first&.first || 0
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in bot_traffic_count: #{e.message}"
      nil
    end

    # Top bot user agents
    def top_bot_user_agents(start_time, limit = 20)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, limit)
          SELECT
            user_agent,
            COUNT(*) as event_count,
            COUNT(DISTINCT ip_address) as unique_ips
          FROM events
          WHERE timestamp >= ? AND is_bot = true AND user_agent IS NOT NULL
          GROUP BY user_agent
          ORDER BY event_count DESC
          LIMIT ?
        SQL

        # DuckDB returns arrays: [user_agent, event_count, unique_ips]
        result.to_a.map do |row|
          {
            user_agent: row[0],   # row[0] = user_agent
            event_count: row[1],  # row[1] = event_count
            unique_ips: row[2]    # row[2] = unique_ips
          }
        end
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in top_bot_user_agents: #{e.message}"
      nil
    end

    # Bot traffic timeline (hourly breakdown)
    def bot_traffic_timeline(start_time, end_time)
      service.with_connection do |conn|
        result = conn.query(<<~SQL, start_time, end_time)
          SELECT
            DATE_TRUNC('hour', timestamp) as hour,
            SUM(CASE WHEN is_bot = true THEN 1 ELSE 0 END) as bot_count,
            SUM(CASE WHEN is_bot = false THEN 1 ELSE 0 END) as human_count
          FROM events
          WHERE timestamp >= ? AND timestamp < ?
          GROUP BY hour
          ORDER BY hour
        SQL

        # Convert to hash with Time keys
        # DuckDB returns arrays: [hour, bot_count, human_count]
        result.to_a.to_h do |row|
          [
            row[0],  # row[0] = hour
            {
              "bot_count" => row[1],      # row[1] = bot_count
              "human_count" => row[2],    # row[2] = human_count
              "total" => row[1] + row[2]
            }
          ]
        end
      end
    rescue StandardError => e
      Rails.logger.error "[EventDdb] Error in bot_traffic_timeline: #{e.message}"
      nil
    end
  end
end