require 'ostruct'

module PVE::CTTemplate
  class Base
    attr_reader :options

    def initialize **opts
      @options = OpenStruct.new opts
      @virts = Proxmox::LXC.all + Proxmox::Qemu.all
    end

    def name() options.name end
    def node() options.node end
    def arch() options.arch || 'amd64' end
    def vmid() options.vmid end
    def ostype() options.ostype end
    def cmode() options.cmode || 'shell' end
    def cores() options.cores || 1 end
    def description() options.description || '' end
    def hostname() options.hostname || name end
    def memory() options.memory || 1024 end
    def swap() options.swap || 0 end
    def unprivileged() options.unprivileged() || 1 end

    def ssh_public_keys
      options[:'ssh-public-keys'] ||
        File.read( options[:'ssh-public-keys-file'] || '/root/.ssh/authorized_keys')
    end

    def _ipv4 ip, gw
      return [ip, nil]  if %w[dhcp].include? ip
      ip = IPAddress::IPv4.new ip
      [ip.to_string, gw || ip.hosts.last.to_s]
    end

    def _ipv6 ip, gw
      return [ip, nil]  if %w[dhcp auto].include? ip
      ip = IPAddress::IPv6.new ip
      [ip.to_string, gw || ip.hosts.last.to_s]
    end

    def net0()
      if options.ipv4 || options.ipv6
        ipv4, gw4 = _ipv4( options.ipv4, options.gateway4)
        ipv6, gw6 = _ipv6( options.ipv6, options.gateway6)
        {
          name: 'eth0',
          bridge: 'vmbr1',
          ip: ipv4, ip6: ipv6,
          gw: gw4, gw6: gw6,
        }
      end
    end
    def net1() nil end
    def net2() nil end
    def net3() nil end
  end

  class Default < Base
    def self.help
      nil
    end

    def self.requirements
      {
        node:                      [:string,  false, "Create CT on this node."],
        name:                      [:string,  true,  "Set (uniq) name"],
        arch:                      [:enum,    false, "Architecture", %w[amd64 i386 arm64 armhf]],
        vmid:                      [:numeric, true,  "VM-ID.  Proxmox internal number (100...)"],
        ostype:                    [:string,  true,  "OS-Type (OS or distribution)"],
        cmode:                     [:enum,    false, "Console-mode", %w[shell console tty]],
        cores:                     [:numeric, false, "Count of cores"],
        description:               [:string,  false, "Description.  Eg. What should this CT do?"],
        hostname:                  [:string,  false, "Hostname"],
        memory:                    [:numeric, false, "How much memory CT could use?"],
        swap:                      [:numeric, false, "How much CT can swap?"],
        unprivileged:              [:boolean, false, "Unprivileged are restricted to own UID/GID-space."],
        :'ssh-public-keys' =>      [:string,  false, "SSH-Public-Keys, which should be added to root-user in CT."],
        :'ssh-public-keys-file' => [:string,  false, "Read SSH-Public-Keys from file."],
        ipv4:                      [:string,  false, "IPv4-Address with net-size."],
        gateway4:                  [:string,  false, "IPv4-Address of gateway."],
        ipv6:                      [:string,  false, "IPv6-Address with net-size or auto."],
        gateway6:                  [:string,  false, "IPv6-Address of gateway."],
        storage:                   [:string,  false, "Device will be create on this Storage (default: local"],
      }
    end
  end

  class Datacenter < Base
    def self.help
      <<-EOF.gsub /^ {6}/, ''
      Datacenter provides an interface for special network-settings.
      Networks in Datacenters are often based on this behaviour:
      A Network has an ID like 99.
      This defines the VLANs: 2099 for Layer2/3099 for Layer3.
      The IPv4-Range would be 10.99.0.0/16, but container will be put static in 10.99.255.0/24.
      IPv6 uses RADV, so we do not need to know the IPv6-Range => auto.
      VMID can be generated by Network-ID, too: smallest unused VMID in 100*ID.
      EOF
    end

    def self.requirements
      {
        node:                      [:string,  false, "Create CT on this node."],
        name:                      [:string,  true,  "Set (uniq) name"],
        arch:                      [:enum,    false, "Architecture", %w[amd64 i386 arm64 armhf]],
        vmid:                      [:numeric, false, "VM-ID.  Proxmox internal number (100...)"],
        ostype:                    [:string,  true,  "OS-Type (OS or distribution)"],
        cmode:                     [:enum,    false, "Console-mode", %w[shell console tty]],
        cores:                     [:numeric, false, "Count of cores"],
        description:               [:string,  false, "Description.  Eg. What should this CT do?"],
        hostname:                  [:string,  false, "Hostname"],
        memory:                    [:numeric, false, "How much memory CT could use?"],
        swap:                      [:numeric, false, "How much CT can swap?"],
        unprivileged:              [:boolean, false, "Unprivileged are restricted to own UID/GID-space."],
        :'ssh-public-keys' =>      [:string,  false, "SSH-Public-Keys, which should be added to root-user in CT."],
        :'ssh-public-keys-file' => [:string,  false, "Read SSH-Public-Keys from file."],
        :'network-id' =>           [:numeric, true,  "Put Container to this VLAN and use a random IPv4-Address for this CT."],
        ipv4:                      [:string,  false, "IPv4-Address with net-size or dhcp."],
        gateway4:                  [:string,  false, "IPv4-Address of gateway."],
        ipv6:                      [:string,  false, "IPv6-Address with net-size or auto|dhcp."],
        gateway6:                  [:string,  false, "IPv6-Address of gateway."],
        storage:                   [:string,  false, "Device will be create on this Storage (default: root)"],
        ostemplate:                [:string,  false, "OS-Template eg. local:vztmpl/superlinux-1.2-amd64.tar.xz"],
      }
    end

    def node() options.node || 'svc1' end
    def ostype() options.ostype || 'debian' end
    def memory() options.memory || 2048 end
    def storage() options.storage || 'root' end

    def network_id
      return @network_id  if @network_id
      expect = 0..12
      nid = options[:'network-id']
      unless nid == nid.to_i.to_s && expect.include?( nid.to_i)
        raise ArgumentError, "Network ID must be #{expect.inspect}.  Given: #{nid.inspect}"
      end
      @network_id = nid.to_i
    end

    def net0
      ipv4, gw4 =
        if options.ipv4
          _ipv4( options.ipv4, options.gateway4)
        else
          self.ipv4_gw
        end
      ipv6, gw6 =
        if options.ipv6
          _ipv6( options.ipv6, options.gateway6)
        else
          ['auto', nil]
        end
      {
        name: 'eth0',
        bridge: 'vmbr1',
        tag: 2000+network_id,
        mtu: 9166,
        firewall: 1,
        ip: ipv4, gw: gw4,
        ip6: ipv6, gw6: gw6,
      }.delete_if {|k,v| v.nil? }
    end

    def vmid
      super || ((0...100).map {|i| "#{100*network_id+i}" } - @virts.map( &:vmid)).first
    end

    def network
      IPAddress::IPv4.new "10.#{network_id}.255.0/24"
    end

    def ipv4_gw
      return @ipv4_gw  if @ipv4_gw
      ipv4s = network.hosts
      @virts.each do |v|
        v.config[:network].each {|n| ipv4s.delete n[:ip]  if n[:ip] }
      end
      @ipv4_gw = [ipv4s.first.to_string, network.last.to_s]
    end

    def ostemplate
      @ostemplate ||=
        options.ostemplate ||
          case ostype
          when 'debian'
            # TODO: how to determine which template?
            'local:vztmpl/debian-11-standard_11.0-1_amd64.tar.gz'
          else
            raise ArgumentError, "OS-Template for ostype #{ostype} not found or ostemplate not provided."
          end
    end
  end
end