::  metadata-store [landscape]:
::
::  data store for application metadata and mappings
::  between groups and resources within applications
::
::  paths are expected to be an existing group path
::  resources are expected to correspond to existing app paths
::
::  note: when scrying for metadata, to make the arguments safe in paths,
::  encode path and path using (scot %t (spat path))
::
::  +watch paths:
::  /all                                  associations + updates
::  /updates                              just updates
::  /app-name/%app-name                   specific app's associations + updates
::
::  +peek paths:
::  /associations                                  all associations
::  /group-indices                                 all group indices
::  /app-indices                                   all app indices
::  /resource-indices                              all resource indices
::  /metadata/%path/%app-name/%path      specific metadatum
::  /app-name/%app-name                            associations for app
::  /group/%path                             associations for group
::
/-  store=metadata-store
/+  *metadata-json, default-agent, verb, dbug, resource, *migrate
|%
+$  card  card:agent:gall
+$  base-state-0
  $:  associations=associations-0
      group-indices=(jug path md-resource:store)
      app-indices=(jug app-name:store [path path])
      resource-indices=(jug md-resource:store path)
  ==
::
+$  associations-0  (map [path md-resource:store] metadata-0)
::
+$  metadata-0
  $:  title=@t
      description=@t
      color=@ux
      date-created=@da
      creator=@p
  ==
::
+$  metadata-1
  $:  title=@t
      description=@t
      color=@ux
      date-created=@da
      creator=@p
      module=term
  ==
::
+$  md-resource-1   [=app-name:store =path]
::
+$  associations-1  (map [path md-resource-1] metadata-1)
::
+$  base-state-1
  $:  associations=associations-1
      group-indices=(jug path md-resource-1)
      app-indices=(jug app-name:store [path path])
      resource-indices=(jug md-resource-1 path)
  ==
::
+$  cached-indices
  $:  group-indices=(jug resource md-resource:store)
      app-indices=(jug app-name:store [group=resource =resource])
      resource-indices=(map md-resource:store resource)
  ==
::
+$  base-state-2
  $:  =associations:store
      ~
  ==
::
+$  state-0   [%0 base-state-0]
+$  state-1   [%1 base-state-0]
+$  state-2   [%2 base-state-0]
+$  state-3   [%3 base-state-1]
+$  state-4   [%4 base-state-1]
+$  state-5   [%5 base-state-1]
+$  state-6   [%6 base-state-1]
+$  state-7   [%7 base-state-2]
+$  versioned-state
  $%  state-0
      state-1
      state-2
      state-3
      state-4
      state-5
      state-6
      state-7
  ==
::
+$  inflated-state
  $:  state-7
      cached-indices
  ==
--
::
=|  inflated-state
=*  state  -
%+  verb  |
%-  agent:dbug
^-  agent:gall
=<
  |_  =bowl:gall
  +*  this  .
      mc    ~(. +> bowl)
      def   ~(. (default-agent this %|) bowl)
  ::
  ++  on-init  on-init:def
  ++  on-save  !>(-.state)
  ++  on-load
    |=  =vase
    ^-  (quip card _this)
    =^  cards  state
      (on-load:mc vase)
    [cards this]
  ::
  ++  on-poke
    |=  [=mark =vase]
    ^-  (quip card _this)
    ?>  (team:title our.bowl src.bowl)
    =^  cards  state
      ?+  mark  (on-poke:def mark vase)
          ?(%metadata-action %metadata-update)
        (poke-metadata-update:mc !<(update:store vase))
      ::
          %import
        (poke-import:mc q.vase)
      ::
        %noun  ~&  +.state  `state
      ==
    [cards this]
  ::
  ++  on-watch
    |=  =path
    ^-  (quip card _this)
    ?>  (team:title our.bowl src.bowl)
    |^
    =/  cards=(list card)
      ?+  path  (on-watch:def path)
          [%all ~]
        (give %metadata-update !>([%associations associations]))
      ::
          [%updates ~]
        ~
      ::
          [%app-name @ ~]
        =/  =app-name:store  i.t.path
        =/  app-indices  (metadata-for-app:mc app-name)
        (give %metadata-update !>([%associations app-indices]))
      ==
    [cards this]
    ::
    ++  give
      |=  =cage
      ^-  (list card)
      [%give %fact ~ cage]~
    --
  ::
  ++  on-peek
    |=  =path
    ^-  (unit (unit cage))
    ?+  path  (on-peek:def path)
        [%y %group-indices ~]     ``noun+!>(group-indices)
        [%y %app-indices ~]       ``noun+!>(app-indices)
        [%y %resource-indices ~]  ``noun+!>(resource-indices)
        [%x %associations ~]      ``noun+!>(associations)
        [%x %app-name @ ~]
      =/  =app-name:store  i.t.t.path
      ``noun+!>((metadata-for-app:mc app-name))
    ::
        [%x %group *]
      =/  group=resource  (de-path:resource t.t.path)
      ``noun+!>((metadata-for-group:mc group))
    ::
        [%x %metadata @ @ @ @ ~]
      =/  =md-resource:store
        [i.t.t.path (de-path:resource t.t.t.path)]
      ``noun+!>((~(get by associations) md-resource))
    ::
        [%x %resource @ *]
      =/  app=term        i.t.t.path
      =/  rid=resource    (de-path:resource t.t.t.path)
      ``noun+!>((~(get by resource-indices) [app rid]))
      
    ::
        [%x %export ~]
      ``noun+!>(-.state)
    ==
  ::
  ++  on-leave  on-leave:def
  ++  on-agent  on-agent:def
  ++  on-arvo   on-arvo:def
  ++  on-fail   on-fail:def
  --
::
|_  =bowl:gall
::
++  on-load
  |=  =vase
  ^-  (quip card _state)
  =/  old  !<(versioned-state vase)
  =|  cards=(list card)
  |^
  =*  loop  $
  ?:  ?=(%7 -.old)
    :-  cards
    %_  state
         associations
       associations.old
      ::
         resource-indices
       (rebuild-resource-indices associations.old)
      ::
         group-indices
      (rebuild-group-indices associations.old)
      ::
        app-indices
      (rebuild-app-indices associations.old)
    ==
  ?:  ?=(%6 -.old)
    =/  old-assoc=associations-1
      (migrate-app-to-graph-store %chat associations.old)
    $(old [%7 (associations-1-to-2 old-assoc) ~])
  ::
  ?:  ?=(%5 -.old)
    =/  associations=associations-1
      (migrate-app-to-graph-store %publish associations.old)
    %_    $
      -.old  %6
      associations.old  associations
    ==
  ::  pre-breach, can safely throw away
  loop(old *state-7)
  ::
  ++  associations-1-to-2
    |=  assoc=associations-1
    ^-  associations:store
    %-  ~(gas by *associations:store)
    %+  murn
      ~(tap by assoc)
    |=  [[group=path m=md-resource-1] met=metadata-1]
    %+  biff  (de-path-soft:resource group)
    |=  g=resource
    %+  bind  (md-resource-1-to-2 m)
    |=  =md-resource:store 
    [md-resource g (metadata-1-to-2 met)]
  ::
  ++  md-resource-1-to-2
    |=  m=md-resource-1
    ^-  (unit md-resource:store)
    %+  bind  (de-path-soft:resource path.m)
    |=(rid=resource [app-name.m rid])
  ::
  ++  metadata-1-to-2
    |=  m=metadata-1
    %*  .  *metadatum:store
      title         title.m
      description   description.m
      color         color.m
      date-created  date-created.m
      creator       creator.m
      module        module.m
    ==
  ::
  ++  rebuild-resource-indices
    |=  =associations:store
    %-  ~(gas by *(map md-resource:store resource))
    %+  turn  ~(tap by associations)
    |=  [r=md-resource:store g=resource =metadatum:store]
    [r g] 
  ::
  ++  rebuild-group-indices
    |=  =associations:store
    %-  ~(gas ju *(jug resource md-resource:store))
    %+  turn
      ~(tap by associations)
    |=  [r=md-resource:store g=resource =metadatum:store]
    [g r]
  ::
  ++  rebuild-app-indices
    |=  =associations:store
    %-  ~(gas ju *(jug app-name:store [group=resource resource]))
    %+  turn  ~(tap by associations)
    |=  [r=md-resource:store g=resource =metadatum:store]
    [app-name.r g resource.r]
  ::
  ++  migrate-app-to-graph-store
    |=  [app=@tas associations=associations-1]
    ^-  associations-1
    %-  malt
    %+  turn  ~(tap by associations)
    |=  [[=path md-resource=md-resource-1] m=metadata-1]
    ^-  [[^path md-resource-1] metadata-1]
    ?.  =(app-name.md-resource app)  
      [[path md-resource] m]
    =/  new-path=^path
      ?.  ?=([@ @ ~] path.md-resource)
        path.md-resource
      ship+path.md-resource
    [[path [%graph new-path]] m(module app)]
  --
++  poke-metadata-update
  |=  upd=update:store
  ^-  (quip card _state)
  ?>  (team:title [our src]:bowl)
  ?+  -.upd  !!
      %add     (handle-add +.upd)
      %remove  (handle-remove +.upd)
      %initial-group  (handle-initial-group +.upd)
  ==
::
++  poke-import
  |=  arc=*
  ^-  (quip card _state)
  |^
  =^  cards  state  
    (on-load !>([%7 (remake-metadata ;;(tree-metadata +.arc))]))
  :_  state
  %+  weld  cards
  %+  turn  ~(tap in ~(key by group-indices))
  |=  rid=resource
  %-  poke-our
  ?:  =(entity.rid our.bowl)
    :-  %metadata-push-hook
    push-hook-action+!>([%add rid])
  :-  %metadata-pull-hook
  pull-hook-action+!>([%add [entity .]:rid])
  ::
  ++  poke-our
    |=  [app=term =cage]
    ^-  card
    [%pass / %agent [our.bowl app] %poke cage]
  ::
  +$  tree-metadata
    $:  associations=(tree [md-resource:store [resource metadatum:store]])
        ~
    ==
  ::
  ++  remake-metadata
    |=  tm=tree-metadata
    ^-  base-state-2
    :*  (remake-map associations.tm)
        ~
    ==
  --
::
++  handle-add
  |=  [group=resource =md-resource:store =metadatum:store]
  ^-  (quip card _state)
  :-  %+  send-diff  app-name.md-resource
      [%add group md-resource metadatum]
  %=  state
      associations
    (~(put by associations) md-resource [group metadatum])
  ::
      app-indices
    %+  ~(put ju app-indices)
      app-name.md-resource
    [group resource.md-resource]
  ::
      resource-indices
    (~(put by resource-indices) md-resource group)
  ::
      group-indices
    (~(put ju group-indices) group md-resource)
  ==
::
++  handle-remove
  |=  [group=resource =md-resource:store]
  ^-  (quip card _state)
  :-  (send-diff app-name.md-resource [%remove group md-resource])
  %=  state
      associations
    (~(del by associations) md-resource)
  ::
      app-indices
    %+  ~(del ju app-indices)
      app-name.md-resource
    [group resource.md-resource]
  ::
      resource-indices
    (~(del by resource-indices) md-resource)
  ::
      group-indices
    (~(del ju group-indices) group md-resource)
  ==
::
++  handle-initial-group
  |=  [group=resource =associations:store]
  =/  assocs=(list [=md-resource:store grp=resource =metadatum:store])
    ~(tap by associations)
  =|  cards=(list card)
  |-
  ?~  assocs
    [cards state]
  =,  assocs
  ?>  =(group grp.i)
  =^  new-cards  state
    (handle-add group [md-resource metadatum]:i)
  $(cards (weld cards new-cards), assocs t)
::
++  metadata-for-app
  |=  =app-name:store
  ^+  associations
  %+  roll  ~(tap in (~(gut by app-indices) app-name ~))
  |=  [[group=resource rid=resource] out=associations:store]
  =/  =md-resource:store
    [app-name rid]
  =/  [resource =metadatum:store]
    (~(got by associations) md-resource)
  (~(put by out) md-resource [group metadatum])
::
++  metadata-for-group
  |=  group=resource
  =/  resources=(set md-resource:store)
    (~(get ju group-indices) group)
  %+  roll
    ~(tap in resources)
  |=  [=md-resource:store out=associations:store]
  =/  [resource =metadatum:store]
    (~(got by associations) md-resource)
  (~(put by out) md-resource [group metadatum])
::
++  send-diff
  |=  [=app-name:store =update:store]
  ^-  (list card)
  |^
  %-  zing
  :~  (update-subscribers /all update)
      (update-subscribers /updates update)
      (update-subscribers [%app-name app-name ~] update)
  ==
  ::
  ++  update-subscribers
    |=  [pax=path =update:store]
    ^-  (list card)
    [%give %fact ~[pax] %metadata-update !>(update)]~
  --
--