-- Cache: ~/.cache total and its four largest subdirectories.
--
-- Reads a cache file written by bin/cache-sample.sh. du walks the tree and
-- costs about 100ms, which cannot happen on a 2-second draw.

local card = require 'lib.card'
local data = require 'lib.data'

local CACHE = (os.getenv('XDG_CACHE_HOME') or (os.getenv('HOME') .. '/.cache'))
  .. '/udt/cachesize.txt'

local M = {}

function M.draw(cr, rect, colors)
  local inner = card.card(cr, rect, colors)
  local function clamp(v, lo, hi) return math.max(lo, math.min(hi, v)) end
  local label_size = clamp(inner.w * 0.030, 10, 16)
  local big_size   = clamp(inner.w * 0.075, 22, 46)

  card.font(cr, card.FONT_MONO, label_size, false)
  card.rgba(cr, colors.label)
  card.text(cr, inner.x, inner.y + label_size, 'CACHE')

  local c = data.du_parse(data.slurp(CACHE) or '')
  if not c then
    card.rgba(cr, colors.label)
    card.font(cr, card.FONT_UI, label_size * 1.2, true)
    card.text(cr, inner.x, inner.y + label_size * 3.4, 'no cache data')
    card.font(cr, card.FONT_MONO, label_size, false)
    card.text(cr, inner.x, inner.y + label_size * 5, 'bin/cache-sample.sh')
    return
  end

  card.font(cr, card.FONT_HEAVY, big_size, false)
  card.rgba(cr, colors.body)
  card.text(cr, inner.x, inner.y + label_size + big_size, c.total.label)

  local ey = inner.y + label_size + big_size + label_size * 2
  local step = label_size * 2.2

  card.font(cr, card.FONT_MONO, label_size, false)
  for i, e in ipairs(c.items) do
    if ey + step > inner.y + inner.h then break end
    -- The biggest offender is the point of the card, so it carries colour:
    -- critical when it is over half the total, warning otherwise. The rest
    -- stay in the ordinary value colour so the eye lands on the one to delete.
    local colour = colors.value
    if i == 1 then
      local share = c.total.bytes > 0 and (e.bytes / c.total.bytes) or 0
      colour = share > 0.5 and colors.critical or colors.warning
    end
    card.rgba(cr, colors.label)
    -- Long names are truncated rather than allowed to collide with the size.
    local name = e.name
    if #name > 18 then name = name:sub(1, 17) .. '\u{2026}' end
    card.text(cr, inner.x, ey, name)
    card.rgba(cr, colour)
    card.text_right(cr, inner.x + inner.w, ey, e.label)
    ey = ey + step
  end
end

return M