(* virt-v2v
 * Copyright (C) 2009-2020 Red Hat Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *)

(* Parse OVF from an externally produced OVA file. *)

open Std_utils
open Tools_utils
open Unix_utils
open Common_gettext.Gettext

open Types
open Utils
open Xpath_helpers

open Printf

type disk = {
  source_disk : Types.source_disk;
  href : string;                (* The <File href> from the OVF file. *)
  compressed : bool;            (* If the file is gzip compressed. *)
}

let xpathctx_of_ovf ovf_filename =
  let doc = Xml.parse_file ovf_filename in

  (* Handle namespaces. *)
  let xpathctx = Xml.xpath_new_context doc in
  Xml.xpath_register_ns xpathctx
                        "ovf" "http://schemas.dmtf.org/ovf/envelope/1";
  Xml.xpath_register_ns xpathctx
                        "rasd" "http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ResourceAllocationSettingData";
  Xml.xpath_register_ns xpathctx
                        "vmw" "http://www.vmware.com/schema/ovf";
  Xml.xpath_register_ns xpathctx
                        "vssd" "http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_VirtualSystemSettingData";

  xpathctx

let rec parse_ovf_from_ova ovf_filename =
  let xpathctx = xpathctx_of_ovf ovf_filename in

  let xpath_string = xpath_string xpathctx
  and xpath_int = xpath_int xpathctx
  and xpath_int64 = xpath_int64 xpathctx in

  (* Search for vm name. *)
  let name =
    match xpath_string "/ovf:Envelope/ovf:VirtualSystem/ovf:Name/text()" with
    | None | Some "" -> None
    | Some _ as name -> name in

  (* Search for memory. *)
  let memory = Option.value ~default:(1024L *^ 1024L) (xpath_int64 "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item[rasd:ResourceType/text()=4]/rasd:VirtualQuantity/text()") in
  let memory = memory *^ 1024L *^ 1024L in

  (* Search for number of vCPUs. *)
  let vcpu = Option.value ~default:1 (xpath_int "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item[rasd:ResourceType/text()=3]/rasd:VirtualQuantity/text()") in

  (* CPU topology.  coresPerSocket is a VMware proprietary extension.
   * I couldn't find out how hyperthreads is specified in the OVF.
   *)
  let cores_per_socket = xpath_int "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item[rasd:ResourceType/text()=3]/vmw:CoresPerSocket/text()" in
  let cpu_topology =
    match cores_per_socket with
    | None -> None
    | Some cores_per_socket when cores_per_socket <= 0 ->
       warning (f_"invalid vmw:CoresPerSocket (%d) ignored")
               cores_per_socket;
       None
    | Some cores_per_socket ->
       let sockets = vcpu / cores_per_socket in
       if sockets <= 0 then (
         warning (f_"invalid vmw:CoresPerSocket < number of cores");
         None
       )
       else
         Some { s_cpu_sockets = sockets; s_cpu_cores = cores_per_socket;
                s_cpu_threads = 1 } in

  (* BIOS or EFI firmware? *)
  let firmware_opt = xpath_string "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/vmw:Config[@vmw:key=\"firmware\"]/@vmw:value" in
  let firmware =
    match firmware_opt with
    | Some "efi" -> UEFI
    | Some "bios" -> BIOS
    | None -> UnknownFirmware
    | Some s ->
      error (f_"unknown Config:firmware value %s (expected \"bios\" or \"efi\")") s;
  in

  name, memory, vcpu, cpu_topology, firmware,
  parse_disks xpathctx, parse_removables xpathctx, parse_nics xpathctx

(* Hard disks (ResourceType = 17). *)
and parse_disks xpathctx =
  let xpath_string = xpath_string xpathctx
  and xpath_int = xpath_int xpathctx in

  let disks = ref [] in
  let expr = "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item[rasd:ResourceType/text()=17]" in
  let obj = Xml.xpath_eval_expression xpathctx expr in
  let nr_nodes = Xml.xpathobj_nr_nodes obj in
  for i = 0 to nr_nodes-1 do
    let n = Xml.xpathobj_node obj i in
    Xml.xpathctx_set_current_context xpathctx n;

    (* XXX We assume the OVF lists these in order.
       let address = xpath_int "rasd:AddressOnParent/text()" in
     *)

    (* Find the parent controller. *)
    let parent_id = xpath_int "rasd:Parent/text()" in
    let controller =
      match parent_id with
      | None -> None
      | Some id -> parent_controller xpathctx id in

    Xml.xpathctx_set_current_context xpathctx n;
    let file_id =
      Option.value ~default:"" (xpath_string "rasd:HostResource/text()") in
    let rex = PCRE.compile "^(?:ovf:)?/disk/(.*)" in
    if PCRE.matches rex file_id then (
      (* Chase the references through to the actual file name. *)
      let file_id = PCRE.sub 1 in
      let expr = sprintf "/ovf:Envelope/ovf:DiskSection/ovf:Disk[@ovf:diskId='%s']/@ovf:fileRef" file_id in
      let file_ref =
        match xpath_string expr with
        | None -> error (f_"error parsing disk fileRef")
        | Some s -> s in
      let expr = sprintf "/ovf:Envelope/ovf:References/ovf:File[@ovf:id='%s']/@ovf:href" file_ref in
      let href =
        match xpath_string expr with
        | None -> error (f_"no href in ovf:File (id=%s)") file_ref
        | Some s -> s in

      let expr = sprintf "/ovf:Envelope/ovf:References/ovf:File[@ovf:id='%s']/@ovf:compression" file_ref in
      let compressed =
        match xpath_string expr with
        | None | Some "identity" -> false
        | Some "gzip" -> true
        | Some s -> error (f_"unsupported compression in OVF: %s") s in

      let disk = {
        source_disk = {
          s_disk_id = i;
          s_controller = controller;
        };
        href = href;
        compressed = compressed;
      } in
      List.push_front disk disks;
    ) else
      error (f_"could not parse disk rasd:HostResource from OVF document")
  done;
  List.rev !disks

(* Floppies (ResourceType = 14), CDs (ResourceType = 15) and
 * CDROMs (ResourceType = 16).  (What is the difference?)  Try hard
 * to preserve the original ordering from the OVF.
 *)
and parse_removables xpathctx =
  let xpath_int = xpath_int xpathctx in

  let removables = ref [] in
  let expr = "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item[rasd:ResourceType/text()=14 or rasd:ResourceType/text()=15 or rasd:ResourceType/text()=16]" in
  let obj = Xml.xpath_eval_expression xpathctx expr in
  let nr_nodes = Xml.xpathobj_nr_nodes obj in
  for i = 0 to nr_nodes-1 do
    let n = Xml.xpathobj_node obj i in
    Xml.xpathctx_set_current_context xpathctx n;
    let id =
      match xpath_int "rasd:ResourceType/text()" with
      | None -> assert false
      | Some (14|15|16 as i) -> i
      | Some _ -> assert false in

    let slot = xpath_int "rasd:AddressOnParent/text()" in

    (* Find the parent controller. *)
    let parent_id = xpath_int "rasd:Parent/text()" in
    let controller =
      match parent_id with
      | None -> None
      | Some id -> parent_controller xpathctx id in

    let typ =
      match id with
      | 14 -> Floppy
      | 15 | 16 -> CDROM
      | _ -> assert false in
    let disk = {
      s_removable_type = typ;
      s_removable_controller = controller;
      s_removable_slot = slot;
    } in
    List.push_front disk removables;
  done;
  List.rev !removables

(* Search for networks ResourceType: 10 *)
and parse_nics xpathctx =
  let xpath_string = xpath_string xpathctx in

  let nics = ref [] in
  let expr = "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item[rasd:ResourceType/text()=10]" in
  let obj = Xml.xpath_eval_expression xpathctx expr in
  let nr_nodes = Xml.xpathobj_nr_nodes obj in
  for i = 0 to nr_nodes-1 do
    let n = Xml.xpathobj_node obj i in
    Xml.xpathctx_set_current_context xpathctx n;
    let vnet, vnet_type =
      match xpath_string "rasd:Connection/text()" with
      | Some connection -> connection, Bridge
      | None -> sprintf "eth%d" i, Network in
    let mac = xpath_string "rasd:Address/text()" in
    let nic_model =
      match xpath_string "rasd:ResourceSubType/text()" with
      | Some "E1000" -> Some Source_e1000
      | Some model -> Some (Source_other_nic (String.lowercase_ascii model))
      | None -> None in
    let nic = {
      s_mac = mac;
      s_nic_model = nic_model;
      s_vnet = vnet;
      s_vnet_type = vnet_type
    } in
    List.push_front nic nics
  done;
  List.rev !nics

(* Helper function to return the parent controller of a disk. *)
and parent_controller xpathctx id =
  let xpath_int = xpath_int xpathctx in

  let expr = sprintf "/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/ovf:Item[rasd:InstanceID/text()=%d]/rasd:ResourceType/text()" id in
  let controller = xpath_int expr in

  (* 5: IDE, 6: SCSI controller, 20: SATA *)
  match controller with
  | Some 5 -> Some Source_IDE
  | Some 6 -> Some Source_SCSI
  | Some 20 -> Some Source_SATA
  | None ->
     warning (f_"ova disk has no parent controller, please report this as \
                 a bug supplying the *.ovf file extracted from the ova");
     None
  | Some controller ->
     warning (f_"ova disk has an unknown VMware controller type (%d), please \
                 report this as a bug supplying the *.ovf file extracted \
                 from the ova")
             controller;
     None

let parse_disks ovf_filename =
  let xpathctx = xpathctx_of_ovf ovf_filename in
  parse_disks xpathctx
