--!nonstrict
-- Pulsar Mouse battery/charging status - [[desktop_widget]].
--
-- Data source: ~/.cache/pulsar-mouse/battery.json, written by
-- pulsar-mouse-gui's tray/Home page poll (every 60s while it's running) -
-- reading that costs nothing extra on the mouse's wireless link. If that
-- file is missing or older than STALE_AFTER (the GUI/tray isn't running),
-- falls back to a direct `pulsar-mouse --battery-json` read instead, so the
-- widget still works standalone, just with its own USB round-trip.
--
-- For a wired mouse (no battery to report), --battery-json returns
-- {"wireless": false} rather than an error - renders a minimal "Wired"
-- placeholder instead of battery info. Unlike bar.luau, there's no
-- desktopWidget.setVisible() to hide entirely, so this is the closest
-- available equivalent.
--
--   noctalia.readFile(path)     cheap path - reads the GUI's last reading
--   noctalia.runAsync(cmd, cb)  fallback path - direct CLI read
--   noctalia.json.decode(str)   both paths return JSON on stdout/in the file
--   desktopWidget.render(tree)  declarative UI tree

local STATE_PATH = "~/.cache/pulsar-mouse/battery.json"
local STALE_AFTER = 180 -- seconds - 3x the GUI's own 60s poll interval
local LOW_POWER_DEFAULT = 15 -- used when the driver has no low-power-threshold
                              -- getter (e.g. nordic.py) or it hasn't been read yet

local color = noctalia.getConfig("color")
-- The other three states. Defaulted in plugin.toml to the values these were
-- previously hardcoded to, so an existing install renders identically.
local chargingColor = noctalia.getConfig("charging_color")
local warningColor = noctalia.getConfig("warning_color")
local errorColor = noctalia.getConfig("error_color")
local showProgress = noctalia.getConfig("show_progress")
local showPercent = noctalia.getConfig("show_percent")
local glyphSize = noctalia.getConfig("glyph_size")

local wireless = true -- assume true until a read says otherwise
local percent = nil
local charging = false
local lowPowerThreshold = nil
local errorText = nil
local checkingCli = false

local function statusColor()
  if errorText ~= nil then
    return errorColor
  end
  if charging then
    return chargingColor
  end
  if percent ~= nil and percent <= (lowPowerThreshold or LOW_POWER_DEFAULT) then
    return warningColor
  end
  return color
end

local function statusGlyph()
  local name = (errorText ~= nil or percent == nil) and "mouse-off" or "mouse-filled"
  return ui.glyph({ key = "glyph", name = name, size = glyphSize, color = statusColor() })
end

local function render()
  if not wireless then
    desktopWidget.render(ui.column({ gap = 6, align = "center" }, {
      ui.glyph({ name = "plug", size = glyphSize, color = "outline" }),
      ui.label({ text = noctalia.tr("ui.wired"), fontSize = 12, color = "outline" }),
    }))
    return
  end

  -- Every row below gets an explicit, semantic `key` - this list isn't
  -- structurally stable (the 2nd slot alone can hold an error label, a
  -- "--" placeholder, or a percent label depending on state; the progress
  -- row appears/disappears independently), so without a key the reconciler
  -- matches purely by (type, position) and can attach a stale node to a
  -- different logical row across renders - same bug class fixed in
  -- panel.luau, just never applied here.
  local rows = {
    statusGlyph(),
  }

  if errorText ~= nil then
    -- Diagnostic, not decorative - stays visible even with show_percent off,
    -- since otherwise a broken setup would just silently show a bare glyph.
    table.insert(rows, ui.label({ key = "status", text = errorText, fontSize = 12, color = errorColor }))
  elseif showPercent and percent == nil then
    table.insert(rows, ui.label({ key = "status", text = "--", fontSize = 20, color = "outline" }))
  elseif showPercent then
    local text = tostring(percent) .. "%"
    if charging then
      text = text .. " " .. noctalia.tr("ui.charging")
    end
    table.insert(rows, ui.label({ key = "status", text = text, fontSize = 18, fontWeight = "bold", color = statusColor() }))
  end

  if showProgress and percent ~= nil then
    table.insert(rows, ui.progress({
      key = "progress",
      progress = percent / 100,
      fill = statusColor(),
      width = 120,
      height = 6,
      radius = 3,
    }))
  end

  desktopWidget.render(ui.column({ gap = 6, align = "center" }, rows))
end

-- Fallback: no fresh state file, so ask the driver directly. Only one of
-- these in flight at a time - update() ticks every 30s and a CLI round-trip
-- can occasionally take longer than that if the mouse's RF link is asleep.
local function readViaCli()
  if checkingCli then
    return
  end
  if not noctalia.commandExists("pulsar-mouse") then
    errorText = noctalia.tr("ui.not-installed")
    render()
    return
  end
  checkingCli = true
  noctalia.runAsync("pulsar-mouse --battery-json", function(result)
    checkingCli = false
    if type(result) ~= "table" or result.timedOut or result.exitCode ~= 0 then
      errorText = noctalia.tr("ui.no-mouse")
      render()
      return
    end
    local decoded = noctalia.json.decode(result.stdout or "")
    if type(decoded) ~= "table" then
      errorText = noctalia.tr("ui.no-mouse")
      render()
      return
    end
    if decoded.wireless == false then
      wireless = false
      errorText = nil
      render()
      return
    end
    if decoded.battery_percent == nil then
      errorText = noctalia.tr("ui.no-mouse")
      render()
      return
    end
    wireless = true
    errorText = nil
    percent = decoded.battery_percent
    charging = decoded.power_connected == true
    -- Unlike signal, this has a synchronous getter, so it IS available here
    -- (nil on a driver without one, e.g. nordic.py - falls back to LOW_POWER_DEFAULT).
    lowPowerThreshold = decoded.low_power_threshold
    render()
  end, 10000)
end

local function readState()
  local contents = noctalia.readFile(STATE_PATH)
  if type(contents) ~= "string" or contents == "" then
    readViaCli()
    return
  end

  local decoded = noctalia.json.decode(contents)
  if type(decoded) ~= "table" or decoded.battery_percent == nil then
    readViaCli()
    return
  end

  local age = os.time() - (decoded.updated_at or 0)
  if age > STALE_AFTER then
    readViaCli()
    return
  end

  wireless = true
  errorText = nil
  percent = decoded.battery_percent
  charging = decoded.power_connected == true
  lowPowerThreshold = decoded.low_power_threshold
  render()
end

function update()
  noctalia.setUpdateInterval(30000)
  readState()
end

render()