# A board two nodes share. A change to a card goes whole to the other node
# (send changed { ..at }), and a card the other node sends is taken whole
# (cards[k] = Card { ..remote }) when it is the later change: by its time,
# then by the node's name. So both boards end the same, whatever order the
# changes come in, and after the nodes were cut apart and joined again.
#
# Each node runs it with a key of its own and links to the other, sealed:
#   pure-serve --module shared-board.pmod --store a --key a.key --name a \
#       --link-port 7001 --send changed=pure://127.0.0.1:7002/remote \
#       --seal changed=B_KEY --sender b.changed=B_KEY
# then tells the app its name: POST /inputs/name {"name": "a"}. Upgraded
# one node after the other, a node takes the other's changes by field name
# (Pure docs/design/014-fields-by-name.md): add a field to the card and the
# output, nowhere else.
use vega

record Card {
  title: text
  who: text  # whose card it is
  lane = 0   # 0 to do, 1 doing, 2 done
  node: text # the node that changed it last
  since = 0  # when: milliseconds since 1970
}

state cards: list of Card by title
state at: index of cards
state me: text = "me"

input add = text
input forward = key ArrowRight
input back = key ArrowLeft
input up = key ArrowUp
input down = key ArrowDown
input name = message {
  name: text
}
input assign = message {
  title: text
  who: text
}
output changed = message {
  title: text
  who: text
  lane: u32
  node: text
  since: number
}
input remote = message like changed

fn lane_name(lane) = if lane == 0 { "to do" } else if lane == 1 { "doing" } else { "done" }

on add {
  cards.add(Card { title: add, since: now, node: me })
  at = cards[add]
  send changed { ..at }
}
on forward.down {
  at.lane = min(at.lane + 1, 2)
  at.since = now
  at.node = me
  send changed { ..at }
}
on back.down {
  at.lane = max(at.lane - 1, 0)
  at.since = now
  at.node = me
  send changed { ..at }
}
on up.down { at = at - 1 }
on down.down { at = at + 1 }
on name { me = name.name }
on assign {
  require cards.has(assign.title)
  cards[assign.title].who = assign.who
  cards[assign.title].since = now
  cards[assign.title].node = me
  send changed { ..cards[assign.title] }
}
on remote {
  if !cards.has(remote.title) {
    cards.add(Card { ..remote })
  } else if (remote.since > cards[remote.title].since ||
             (remote.since == cards[remote.title].since && remote.node > cards[remote.title].node)) {
    cards[remote.title] = Card { ..remote }
  }
}

view title = "{me}'s board"
view counts = "{count(c in cards where c.lane == 0)} to do, {count(c in cards where c.lane == 1)} doing, {count(c in cards where c.lane == 2)} done"

view cards_list = each c in cards {
  label = c.title
  badge = if c.who == "" { lane_name(c.lane) } else { "{c.who}, {lane_name(c.lane)}" }
  tone = if c.lane == 2 { vega.muted } else { vega.when(c.lane == 1, vega.accent) }
}
view cards_list_focus = at.position