# Responsible for logging the actions of admins and moderators.
class StaffActionLogger

  def self.base_attrs
    [:topic_id, :post_id, :context, :subject, :ip_address, :previous_value, :new_value]
  end

  def initialize(admin)
    @admin = admin
    raise Discourse::InvalidParameters.new(:admin) unless @admin && @admin.is_a?(User)
  end

  def log_user_deletion(deleted_user, opts={})
    raise Discourse::InvalidParameters.new(:deleted_user) unless deleted_user && deleted_user.is_a?(User)
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:delete_user],
      ip_address: deleted_user.ip_address.to_s,
      details: [:id, :username, :name, :created_at, :trust_level, :last_seen_at, :last_emailed_at].map { |x| "#{x}: #{deleted_user.send(x)}" }.join("\n")
    }))
  end

  def log_custom(custom_type, details=nil)
    raise Discourse::InvalidParameters.new(:custom_type) unless custom_type

    details ||= {}

    attrs = {}
    StaffActionLogger.base_attrs.each do |attr|
      attrs[attr] = details.delete(attr) if details.has_key?(attr)
    end
    attrs[:details] = details.map {|r| "#{r[0]}: #{r[1]}"}.join("\n")
    attrs[:acting_user_id] = @admin.id
    attrs[:action] = UserHistory.actions[:custom_staff]
    attrs[:custom_type] = custom_type

    UserHistory.create(attrs)
  end

  def log_post_deletion(deleted_post, opts={})
    raise Discourse::InvalidParameters.new(:deleted_post) unless deleted_post && deleted_post.is_a?(Post)

    topic = deleted_post.topic || Topic.with_deleted.find_by(id: deleted_post.topic_id)

    username = deleted_post.user.try(:username) || "unknown"
    name = deleted_post.user.try(:name) || "unknown"
    topic_title = topic.try(:title) || "not found"

    details = [
      "id: #{deleted_post.id}",
      "created_at: #{deleted_post.created_at}",
      "user: #{username} (#{name})",
      "topic: #{topic_title}",
      "post_number: #{deleted_post.post_number}",
      "raw: #{deleted_post.raw}"
    ]

    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:delete_post],
      post_id: deleted_post.id,
      details: details.join("\n")
    }))
  end

  def log_topic_deletion(deleted_topic, opts={})
    raise Discourse::InvalidParameters.new(:deleted_topic) unless deleted_topic && deleted_topic.is_a?(Topic)

    user = deleted_topic.user ? "#{deleted_topic.user.username} (#{deleted_topic.user.name})" : "(deleted user)"

    details = [
      "id: #{deleted_topic.id}",
      "created_at: #{deleted_topic.created_at}",
      "user: #{user}",
      "title: #{deleted_topic.title}"
    ]

    if first_post = deleted_topic.ordered_posts.first
      details << "raw: #{first_post.raw}"
    end

    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:delete_topic],
      topic_id: deleted_topic.id,
      details: details.join("\n")
    }))
  end

  def log_trust_level_change(user, old_trust_level, new_trust_level, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user && user.is_a?(User)
    raise Discourse::InvalidParameters.new(:old_trust_level) unless TrustLevel.valid? old_trust_level
    raise Discourse::InvalidParameters.new(:new_trust_level) unless TrustLevel.valid? new_trust_level
    UserHistory.create!( params(opts).merge({
      action: UserHistory.actions[:change_trust_level],
      target_user_id: user.id,
      details: "old trust level: #{old_trust_level}\nnew trust level: #{new_trust_level}"
    }))
  end

  def log_lock_trust_level(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user && user.is_a?(User)
    UserHistory.create!( params(opts).merge({
      action: UserHistory.actions[user.trust_level_locked ? :lock_trust_level : :unlock_trust_level],
      target_user_id: user.id
    }))
  end

  def log_site_setting_change(setting_name, previous_value, new_value, opts={})
    raise Discourse::InvalidParameters.new(:setting_name) unless setting_name.present? && SiteSetting.respond_to?(setting_name)
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:change_site_setting],
      subject: setting_name,
      previous_value: previous_value,
      new_value: new_value
    }))
  end

  def theme_json(theme)
    ThemeSerializer.new(theme, root:false).to_json
  end

  def strip_duplicates(old,cur)
    return [old,cur] unless old && cur

    old = JSON.parse(old)
    cur = JSON.parse(cur)

    old.each do |k, v|
      next if k == "name"
      next if k == "id"
      if (v == cur[k])
        cur.delete(k)
        old.delete(k)
      end
    end

    [old.to_json, cur.to_json]
  end

  def log_theme_change(old_json, new_theme, opts={})
    raise Discourse::InvalidParameters.new(:new_theme) unless new_theme

    new_json = theme_json(new_theme)

    old_json,new_json = strip_duplicates(old_json,new_json)

    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:change_theme],
      subject: new_theme.name,
      previous_value: old_json,
      new_value: new_json
    }))
  end

  def log_theme_destroy(theme, opts={})
    raise Discourse::InvalidParameters.new(:theme) unless theme
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:delete_theme],
      subject: theme.name,
      previous_value: theme_json(theme)
    }))
  end

  def log_site_text_change(subject, new_text=nil, old_text=nil, opts={})
    raise Discourse::InvalidParameters.new(:subject) unless subject.present?
    UserHistory.create!( params(opts).merge({
      action: UserHistory.actions[:change_site_text],
      subject: subject,
      previous_value: old_text,
      new_value: new_text
    }))
  end

  def log_username_change(user, old_username, new_username, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:change_username],
      target_user_id: user.id,
      previous_value: old_username,
      new_value: new_username
    }))
  end

  def log_name_change(user_id, old_name, new_name, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user_id
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:change_name],
      target_user_id: user_id,
      previous_value: old_name,
      new_value: new_name
    }))
  end

  def log_user_suspend(user, reason, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:suspend_user],
      target_user_id: user.id,
      details: reason
    }))
  end

  def log_user_unsuspend(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:unsuspend_user],
      target_user_id: user.id
    }))
  end

  def log_badge_grant(user_badge, opts={})
    raise Discourse::InvalidParameters.new(:user_badge) unless user_badge
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:grant_badge],
      target_user_id: user_badge.user_id,
      details: user_badge.badge.name
    }))
  end

  def log_badge_revoke(user_badge, opts={})
    raise Discourse::InvalidParameters.new(:user_badge) unless user_badge
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:revoke_badge],
      target_user_id: user_badge.user_id,
      details: user_badge.badge.name
    }))
  end

  def log_check_email(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:check_email],
      target_user_id: user.id
    }))
  end

  def log_show_emails(users, opts={})
    return if users.blank?
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:check_email],
      details: users.map { |u| "[#{u.id}] #{u.username}"}.join("\n")
    }))
  end

  def log_impersonate(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:impersonate],
      target_user_id: user.id
    }))
  end

  def log_roll_up(subnets, opts={})
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:roll_up],
      details: subnets.join(", ")
    }))
  end

  def log_category_settings_change(category, category_params, old_permissions=nil)
    validate_category(category)

    changed_attributes = category.previous_changes.slice(*category_params.keys)

    if !old_permissions.empty? && (old_permissions != category_params[:permissions])
      changed_attributes.merge!({ permissions: [old_permissions.to_json, category_params[:permissions].to_json] })
    end

    changed_attributes.each do |key, value|
      UserHistory.create(params.merge({
        action: UserHistory.actions[:change_category_settings],
        category_id: category.id,
        context: category.url,
        subject: key,
        previous_value: value[0],
        new_value: value[1]
      }))
    end
  end

  def log_category_deletion(category)
    validate_category(category)

    details = [
      "created_at: #{category.created_at}",
      "name: #{category.name}",
      "permissions: #{category.permissions_params}"
    ]

    if parent_category = category.parent_category
      details << "parent_category: #{parent_category.name}"
    end

    UserHistory.create(params.merge({
      action: UserHistory.actions[:delete_category],
      category_id: category.id,
      details: details.join("\n"),
      context: category.url
    }))
  end

  def log_category_creation(category)
    validate_category(category)

    details = [
      "created_at: #{category.created_at}",
      "name: #{category.name}"
    ]

    UserHistory.create(params.merge({
      action: UserHistory.actions[:create_category],
      details: details.join("\n"),
      category_id: category.id,
      context: category.url
    }))
  end

  def log_block_user(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:block_user],
      target_user_id: user.id
    }))
  end

  def log_unblock_user(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:unblock_user],
      target_user_id: user.id
    }))
  end

  def log_grant_admin(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:grant_admin],
      target_user_id: user.id
    }))
  end

  def log_revoke_admin(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:revoke_admin],
      target_user_id: user.id
    }))
  end

  def log_grant_moderation(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:grant_moderation],
      target_user_id: user.id
    }))
  end

  def log_revoke_moderation(user, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:revoke_moderation],
      target_user_id: user.id
    }))
  end

  def log_backup_create(opts={})
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:backup_create],
      ip_address: @admin.ip_address.to_s
    }))
  end

  def log_backup_download(backup, opts={})
    raise Discourse::InvalidParameters.new(:backup) unless backup
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:backup_download],
      ip_address: @admin.ip_address.to_s,
      details: backup.filename
    }))
  end

  def log_backup_destroy(backup, opts={})
    raise Discourse::InvalidParameters.new(:backup) unless backup
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:backup_destroy],
      ip_address: @admin.ip_address.to_s,
      details: backup.filename
    }))
  end

  def log_revoke_email(user, reason, opts={})
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:revoke_email],
      target_user_id: user.id,
      details: reason
    }))
  end

  def log_user_deactivate(user, reason, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:deactivate_user],
      target_user_id: user.id,
      details: reason
    }))
  end

  def log_user_activate(user, reason, opts={})
    raise Discourse::InvalidParameters.new(:user) unless user
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:activate_user],
      target_user_id: user.id,
      details: reason
    }))
  end

  def log_wizard_step(step, opts={})
    raise Discourse::InvalidParameters.new(:step) unless step
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:wizard_step],
      context: step.id
    }))
  end

  def log_change_readonly_mode(state)
    UserHistory.create(params.merge({
      action: UserHistory.actions[:change_readonly_mode],
      previous_value: !state,
      new_value: state
    }))
  end

  private

    def params(opts=nil)
      opts ||= {}
      { acting_user_id: @admin.id, context: opts[:context] }
    end

    def validate_category(category)
      raise Discourse::InvalidParameters.new(:category) unless category && category.is_a?(Category)
    end

end