--!nonstrict
-- Animation preset picker for niri.
--
-- Rewrites the target file (default ~/.config/niri/animations.kdl) with two things: an
-- `include` for the chosen preset and an `animations` block carrying the global speed.
-- Then it asks niri to reload its config.
--
-- Why rewriting it whole is safe: that file exists only for this. Your niri config.kdl is
-- expected to include it LAST, after the base animations — niri's includes are positional
-- and merge field by field, so whatever lands here wins.
--
-- `off` and `slowdown` are direct fields of `animations`, not subsections, which is why the
-- speed override applies on top of a preset that sets its own slowdown:
-- https://github.com/YaLTeR/niri/wiki/Configuration:-Animations
--
-- Presets are listed by FILENAME on purpose. Their headers carry a `Desc:` field, but it is
-- free-form text written by each preset author (often just "imported from https://…"), and
-- it gets worse with presets the user imported themselves. Surfacing it makes the plugin
-- look broken when the problem is somebody else's metadata. A filename always matches what
-- the user sees in the folder.

local PLUGIN_ID = "imjustdoingmypart/niri-animations"

local function cfg(key: string, fallback: string): string
  local v = noctalia.getConfig(key)
  if v == nil or v == "" then return fallback end
  return v
end

local PRESETS_DIR = cfg("presets_dir", "~/.config/niri/animations")
local TARGET      = cfg("target_file", "~/.config/niri/animations.kdl")
local PREFIX      = cfg("include_prefix", "./animations")
local RELOAD      = cfg("reload_command", "niri msg action load-config-file")

local presets: { any } = {}       -- { { file = "bloom.kdl", name = "bloom" } }
local activeFile: string? = nil
local slowdown = 1.0
local animationsOff = false
local status = ""

local function loadPresets()
  presets = {}
  local entries, err = noctalia.listDir(PRESETS_DIR)
  if entries == nil then
    status = `{noctalia.tr("status_read_error")} {PRESETS_DIR}: {err or "?"}`
    return
  end
  table.sort(entries)
  for _, name in ipairs(entries) do
    if string.sub(name, -4) == ".kdl" then
      table.insert(presets, { file = name, name = string.sub(name, 1, #name - 4) })
    end
  end
end

-- Re-read state from the target file so the panel always opens reflecting reality, even if
-- the file was edited by hand or changed from somewhere else.
local function loadCurrent()
  activeFile = nil
  slowdown = 1.0
  animationsOff = false

  local text = noctalia.readFile(TARGET)
  if text == nil then return end

  activeFile = string.match(text, 'include%s+"[^"]*[/\\]([^"/\\]+%.kdl)"')
    or string.match(text, 'include%s+"([^"/\\]+%.kdl)"')

  slowdown = tonumber(string.match(text, "slowdown%s+([%d%.]+)") or "") or 1.0
  animationsOff = string.match(text, "\n%s*off%s*[\n\r]") ~= nil
end

local function apply()
  local out = {
    `// Generated by the Noctalia plugin "{PLUGIN_ID}". Do not edit by hand: this file is`,
    "// rewritten whole whenever a preset is picked or the speed changes.",
    "// Your base/fallback animations belong in a file included BEFORE this one.",
    "",
  }

  if activeFile ~= nil and not animationsOff then
    table.insert(out, `include "{PREFIX}/{activeFile}"`)
    table.insert(out, "")
  end

  table.insert(out, "animations {")
  if animationsOff then
    table.insert(out, "    off")
  else
    table.insert(out, `    slowdown {string.format("%.2f", slowdown)}`)
  end
  table.insert(out, "}")
  table.insert(out, "")

  local _, err = noctalia.writeFile(TARGET, table.concat(out, "\n"))
  if err ~= nil then
    status = `{noctalia.tr("status_write_error")} {TARGET}: {err}`
    noctalia.notify(noctalia.tr("title"), status)
    return
  end

  noctalia.runAsync(RELOAD)

  local speed = `{string.format("%.2f", slowdown)}×`
  if animationsOff then
    status = noctalia.tr("status_off")
  elseif activeFile == nil then
    status = `{noctalia.tr("status_base_pack")} — {speed}`
  else
    status = `{string.sub(activeFile, 1, #activeFile - 4)} — {speed}`
  end
end

-- Index 0 of the dropdown is "no preset"; real presets start at 1.
local function options(): { string }
  local opts = { noctalia.tr("no_preset") }
  for _, p in ipairs(presets) do
    table.insert(opts, p.name)
  end
  return opts
end

local function selectedIndex(): number
  if activeFile == nil then return 0 end
  for i, p in ipairs(presets) do
    if p.file == activeFile then return i end
  end
  return 0
end

local function render()
  panel.render(ui.column({ flexGrow = 1, gap = 16, align = "stretch" }, {
    -- No close button on purpose: on a keyboard-driven WM the panel is dismissed with Esc
    -- or by pressing the shortcut again, so the button is dead weight.
    ui.label({ text = noctalia.tr("title"), fontSize = 16, fontWeight = "bold", color = "on_surface" }),

    ui.row({ gap = 12, align = "center" }, {
      ui.toggle({ checked = not animationsOff, onChange = "onToggleAnimations" }),
      ui.label({
        text = animationsOff and noctalia.tr("animations_off") or noctalia.tr("animations_on"),
        flexGrow = 1,
      }),
      ui.button({ text = noctalia.tr("random"), onClick = "onRandom" }),
    }),

    ui.column({ gap = 6, align = "stretch" }, {
      ui.label({ text = noctalia.tr("preset"), color = "on_surface_variant" }),
      ui.select({ options = options(), selectedIndex = selectedIndex(), onChange = "onPreset" }),
    }),

    ui.column({ gap = 6, align = "stretch" }, {
      ui.label({
        text = `{noctalia.tr("speed")} — {string.format("%.2f", slowdown)}×  ({noctalia.tr("speed_hint")})`,
        color = "on_surface_variant",
      }),
      ui.slider({ min = 0.25, max = 3.0, step = 0.05, value = slowdown, onChange = "onSlowdown" }),
    }),

    ui.label({ text = status, color = "primary" }),
  }))
end

function onOpen(_context)
  loadPresets()
  loadCurrent()
  if status == "" then
    status = `{#presets} {noctalia.tr("status_presets_found")} {PRESETS_DIR}`
  end
  render()
end

function onPreset(index, _text)
  local i = tonumber(index) or 0
  if i <= 0 then
    activeFile = nil
  else
    local p = presets[i]
    activeFile = p and p.file or nil
  end
  animationsOff = false
  apply()
  render()
end

function onToggleAnimations(value)
  animationsOff = not (value == "true")
  apply()
  render()
end

function onSlowdown(value)
  slowdown = tonumber(value) or 1.0
  apply()
  render()
end

function onRandom()
  if #presets == 0 then return end
  activeFile = presets[math.random(1, #presets)].file
  animationsOff = false
  apply()
  render()
end