-- ─────────────────────────────────────────────────────────────────────────────
-- Monitors
--
-- Kuycon P20 on DP-2: 4500x3000 @ 60Hz, 1.5x fractional scale.
-- 4500/1.5 = 3000 and 3000/1.5 = 2000, both integers, so this is a "clean"
-- fractional scale and Hyprland will not complain.
--
-- On HDR --------------------------------------------------------------------
-- GNOME runs this panel in bt2100/HDR. Hyprland CAN do that (cm = "hdr"), but
-- on 0.56.x it currently breaks screencopy: grim screenshots come back empty,
-- and OBS/Sunshine capture and hyprlock's blurred background go with them.
-- Root cause is still open upstream. Since screen capture matters more here
-- than an HDR desktop, the desktop runs SDR at 10-bit and HDR is handed to
-- fullscreen games only, via render.cm_auto_hdr in looks.lua.
--
-- To try full-time HDR anyway, set cm = "hdr" below (or override it in
-- overrides.lua) and read the notes in that file first.
-- ─────────────────────────────────────────────────────────────────────────────

local prefs = require("prefs")

-- Per-output overrides written by Panama Settings, keyed by output name:
--   { ["DP-2"] = {
--       mode = "3840x2160@60", scale = 2, transform = 0,
--       x = 0, y = 0, primary = true,
--   } }
--
-- Only mode, scale, and transform are read. Color management and bit depth
-- stay here, because those are the settings with a documented reason attached
-- (see the header) rather than preferences, and a settings page has no way to
-- explain the screencopy tradeoff at the moment you would be changing it.
local displays = prefs.get("displays", {})
if type(displays) ~= "table" then
    displays = {}
end

local function mode_dimensions(mode)
    if type(mode) ~= "string" then
        return nil, nil
    end
    local width, height, refresh = mode:match("^(%d+)x(%d+)@(%d+%.%d+)$")
    if width == nil then
        width, height, refresh = mode:match("^(%d+)x(%d+)@(%d+)$")
    end
    width, height, refresh = tonumber(width), tonumber(height), tonumber(refresh)
    if width == nil or height == nil or refresh == nil
        or width <= 0 or height <= 0 or refresh <= 0 then
        return nil, nil
    end
    return width, height
end

local function valid_mode(mode)
    local width = mode_dimensions(mode)
    return width ~= nil
end

local function valid_scale(mode, scale)
    local width, height = mode_dimensions(mode)
    if width == nil or type(scale) ~= "number" or scale ~= scale
        or scale <= 0 or scale > 4 then
        return false
    end
    local logical_width = width / scale
    local logical_height = height / scale
    return math.abs(logical_width - math.floor(logical_width + 0.5)) < 0.0001
        and math.abs(logical_height - math.floor(logical_height + 0.5)) < 0.0001
end

local function valid_transform(transform)
    return type(transform) == "number"
        and transform == math.floor(transform)
        and transform >= 0
        and transform <= 3
end

local function valid_coordinate(value)
    return type(value) == "number"
        and value == value
        and value == math.floor(value)
        and value >= -100000
        and value <= 100000
end

local function valid_position(entry)
    return valid_coordinate(entry.x) and valid_coordinate(entry.y)
end

local function valid_primary(entry)
    return type(entry.primary) == "boolean"
end

local function has_layout_fields(entry)
    return entry.x ~= nil or entry.y ~= nil or entry.primary ~= nil
end

local function display_entry(output)
    if type(output) ~= "string" or output == ""
        or output:match("^[%w_.-]+$") == nil then
        return nil
    end
    local entry = displays[output]
    if type(entry) ~= "table" then
        return nil
    end
    if not valid_mode(entry.mode)
        or not valid_scale(entry.mode, entry.scale)
        or not valid_transform(entry.transform) then
        return nil
    end
    -- Legacy records have none of the layout fields and keep automatic
    -- placement. A partially written extended record is unsafe: accepting its
    -- mode but guessing its position could overlap or strand another output.
    if has_layout_fields(entry)
        and (not valid_position(entry) or not valid_primary(entry)) then
        return nil
    end
    return entry
end

local function display_position(entry, fallback)
    if entry ~= nil and has_layout_fields(entry) then
        return string.format("%dx%d", entry.x, entry.y)
    end
    return fallback
end

local shipped_mode = "4500x3000@60"
local shipped_scale = 1.5
local shipped_transform = 0
local dp2 = display_entry("DP-2")

hl.monitor({
    output   = "DP-2",
    mode     = dp2 and dp2.mode or shipped_mode,
    position = display_position(dp2, "0x0"),
    scale    = dp2 and dp2.scale or shipped_scale,
    transform = dp2 and dp2.transform or shipped_transform,

    -- 10-bit output. 4500x3000@60 at 10bpc is ~24 Gbps, right at the edge of
    -- DP 1.4 HBR3, so this relies on DSC. If the display fails to light up or
    -- falls back to a lower mode, drop this line first.
    bitdepth = 10,

    -- "auto" = sRGB at 8bpc, wide gamut at 10bpc. Not HDR; see header.
    cm = "auto",
})

-- Other connected outputs use the same validated per-output store. They keep
-- automatic placement and the compositor's normal color policy; DP-2 alone
-- carries the panel-specific 10-bit policy documented above.
for output, _ in pairs(displays) do
    if output ~= "DP-2" then
        local entry = display_entry(output)
        if entry ~= nil then
            hl.monitor({
                output = output,
                mode = entry.mode,
                position = display_position(entry, "auto"),
                scale = entry.scale,
                transform = entry.transform,
            })
        end
    end
end

-- Any monitor not named above: sane defaults rather than nothing.
hl.monitor({
    output   = "",
    mode     = "preferred",
    position = "auto",
    scale    = "auto",
})

-- ── Workspaces on the primary display only ──────────────────────────────────
--
-- GNOME offered one workspace choice worth reproducing: whether the other
-- screens join in. Off, every monitor has its own workspaces and switching
-- affects whichever one has focus -- Hyprland's own behaviour, so it needs no
-- rules at all. On, workspaces 1-10 are pinned to the primary display and a
-- second screen keeps a workspace of its own that stays put.
--
-- Ten because that is how many the keybinds reach: ALT+1 through ALT+0 in
-- keybinds.lua. Binding more would pin workspaces nothing can navigate to, and
-- binding fewer would leave the last few behaving differently from the rest for
-- no reason a person could see.
--
-- The rules are emitted here rather than written live because Hyprland reads
-- them at config time and offers no way to remove one afterwards: writing an
-- empty monitor leaves the previous binding in place. So the config is the only
-- honest source, and applying a change is a reload.
if prefs.get("workspacesOnPrimaryOnly", false) == true then
    local primary = nil
    for output, entry in pairs(displays) do
        if type(entry) == "table" and entry.primary == true
            and type(output) == "string" and output:match("^[%w_.-]+$") ~= nil then
            primary = output
            break
        end
    end

    -- Without a primary there is nothing to pin to, and guessing one would move
    -- every workspace onto whichever screen happened to sort first.
    if primary ~= nil then
        for i = 1, 10 do
            hl.workspace_rule({ workspace = tostring(i), monitor = primary })
        end
    end
end

return true