-- Conky Lua dashboard: entry point.
--
-- Drawn entirely with Cairo in lua_draw_hook_post; conky.text is empty because
-- Cairo output covers it.

-- Resolve requires relative to this file's directory, since Conky's working
-- directory is wherever it was launched from, not the config's location.
local here = debug.getinfo(1, 'S').source:match('^@(.*/)') or './'
package.path = here .. '?.lua;' .. package.path

require 'cairo'

local card = require 'lib.card'

-- === Layout ===============================================================
-- Order and position are yours: edit this table, nothing else.
-- col/row are grid cells, w/h span cells. Cell size is derived from the
-- surface, so the same table works on a 2560x1080 and a 1920x1080 screen.
local COLS, ROWS = 4, 2

local layout = {
  { widget = 'clock', col = 1, row = 1, w = 1, h = 2 },
}
-- ==========================================================================

local GAP = 16       -- gap between cards, px
local MARGIN = 28    -- outer margin, px

-- #rrggbb -> {r, g, b} as 0-1 floats, which is what Cairo wants.
-- UDT's gen_conky emits hex6, so the conversion lives here rather than in the
-- other repo's renderer.
local function hex(s, fallback)
  local r, g, b = tostring(s or ''):match('^#?(%x%x)(%x%x)(%x%x)$')
  if not r then return fallback or { 1, 0, 1 } end  -- magenta: visibly wrong
  return { tonumber(r, 16) / 255, tonumber(g, 16) / 255, tonumber(b, 16) / 255 }
end

-- The colours, read out of the config file itself.
--
-- NOT via conky_parse('${color3}'): that returns an EMPTY STRING. Conky's
-- colour variables emit renderer escape codes into conky.text, they do not
-- evaluate to a hex string, and ${default_shade_color} is not a variable at all
-- (conky_parse hands the literal text straight back). Verified experimentally;
-- both were checked before this approach was chosen.
--
-- conky.config is also not exposed to Lua (_G.conky is nil) and conky_info
-- carries only cpu_count and update_interval. What Lua does get is
-- conky_config, the path of the config file, so the colours are parsed out of
-- the rendered file. UDT has already substituted real hex into it by then.
--
-- Read once at load, not per frame: the file cannot change without a conky
-- restart, since conky never rereads its config.
local function config_colors()
  local f = io.open(conky_config, 'r')
  if not f then return {} end
  local src = f:read('*a')
  f:close()
  local c = {}
  -- [%w_]+ not %w+: default_color and default_shade_color carry underscores.
  for k, v in src:gmatch("([%w_]+)%s*=%s*'(#%x%x%x%x%x%x)'") do c[k] = v end
  return c
end

local CFG = config_colors()

local function palette()
  return {
    heading   = hex(CFG.color1),
    label     = hex(CFG.color2),
    border    = hex(CFG.color3),
    rule      = hex(CFG.color3),
    value     = hex(CFG.color4),
    highlight = hex(CFG.color5),
    ok        = hex(CFG.color6),
    critical  = hex(CFG.color7),
    body      = hex(CFG.default_color),
    -- The card fill, from default_shade_color (@BODY_SHADE@, `mantle` in
    -- Macchiato). It must NOT reuse color3: that is the border, and filling and
    -- stroking a card in one hue makes the hairline invisible, so the cards
    -- read as blobs instead of the mockup's thin outlines. Every scheme already
    -- defines body_shade, so this needs no palette change.
    surface   = hex(CFG.default_shade_color),
  }
end

-- Cell rect for a layout entry. 1-indexed cols and rows, as the table reads.
local function rect_for(entry, sw, sh)
  local cw = (sw - MARGIN * 2 - GAP * (COLS - 1)) / COLS
  local ch = (sh - MARGIN * 2 - GAP * (ROWS - 1)) / ROWS
  return {
    x = MARGIN + (entry.col - 1) * (cw + GAP),
    y = MARGIN + (entry.row - 1) * (ch + GAP),
    w = cw * (entry.w or 1) + GAP * ((entry.w or 1) - 1),
    h = ch * (entry.h or 1) + GAP * ((entry.h or 1) - 1),
  }
end

-- Widget modules, loaded once and cached. A widget that fails to load must not
-- take the frame down with it, so the require is wrapped.
local widgets = {}
local function widget(name)
  if widgets[name] == nil then
    local ok, mod = pcall(require, 'widgets.' .. name)
    widgets[name] = ok and mod or false
    if not ok then print('dashboard: cannot load widget ' .. name .. ': ' .. tostring(mod)) end
  end
  return widgets[name] or nil
end

-- Draw an error where the dashboard should be.
--
-- Conky reports a Lua fault as a blank screen with no message on any stream, so
-- without this every mistake looks identical to "nothing ran".
local function draw_error(cr, msg, sw)
  cairo_select_font_face(cr, 'Inconsolata Nerd Font', CAIRO_FONT_SLANT_NORMAL,
    CAIRO_FONT_WEIGHT_BOLD)
  cairo_set_font_size(cr, 16)
  cairo_set_source_rgba(cr, 0.93, 0.53, 0.59, 1)  -- literal: the palette may be what failed
  local y = 40
  for line in tostring(msg):gmatch('[^\n]+') do
    cairo_move_to(cr, 24, y)
    cairo_show_text(cr, line)
    y = y + 20
    if y > 400 then break end
  end
  print('dashboard error: ' .. tostring(msg))
end

local function draw(cr, sw, sh, colors)
  for _, entry in ipairs(layout) do
    local w = widget(entry.widget)
    if w then
      w.draw(cr, rect_for(entry, sw, sh), colors)
    else
      -- Name the missing widget in place, rather than leaving a blank cell.
      local r = rect_for(entry, sw, sh)
      local inner = card.card(cr, r, colors)
      card.label(cr, inner.x, inner.y + 16, 'missing: ' .. entry.widget, colors)
    end
  end
end

function conky_main()
  if conky_window == nil then return end
  local s = conky_surface()
  if s == nil then return end
  local cr = cairo_create(s)
  local sw, sh = conky_window.width, conky_window.height
  local ok, err = pcall(function()
    draw(cr, sw, sh, palette())
  end)
  if not ok then draw_error(cr, err, sw) end
  cairo_destroy(cr)
end