Finder -> Bloom (Multi-Monitor) - Hammerspoon

init.lua

-- Finder -> Bloom (Multi-Monitor)
-- Hammerspoon init.lua script so when clicking or alt-tabbing to Finder, it will open Bloom instead.

local bloomName = "Bloom"

local function doRedirect()
    local finder = hs.application.get("Finder")
    -- If Finder isn't even active anymore, stop
    if not finder or not finder:isFrontmost() then return end

    local win = finder:focusedWindow()
    if win then
        local role = win:subrole()
        -- Allow: Get Info (AXInspector), Dialogs, Preferences, etc.
        -- Standard windows we want to block are "AXStandardWindow"
        if role ~= "AXStandardWindow" then
            return 
        end
    end

    -- THE TRICK: launchOrFocus is better for cross-monitor jumps than activate()
    hs.application.launchOrFocus(bloomName)
    
    -- THE HAMMER: Keep forcing Bloom for 1 second until the OS gives in
    local start = hs.timer.secondsSinceEpoch()
    hs.timer.doUntil(function()
        local frontApp = hs.application.frontmostApplication()
        return (frontApp and frontApp:name() == bloomName) or (hs.timer.secondsSinceEpoch() - start > 1.0)
    end, function()
        -- Only hide Finder once Bloom is confirmed as the boss
        local f = hs.application.get("Finder")
        if f then f:hide() end
    end, 0.05) -- Check every 50ms
end

-- 1. Watch for Cmd+Tab / App Activation
finderWatcher = hs.application.watcher.new(function(name, event)
    if name == "Finder" and event == hs.application.watcher.activated then
        -- Run immediately, then again in 200ms to catch the monitor-switch lag
        doRedirect()
        hs.timer.doAfter(0.2, doRedirect)
    end
end):start()

-- 2. Watch for window focus (Dock clicks)
finderFilter = hs.window.filter.new('Finder')
finderFilter:subscribe(hs.window.filter.windowFocused, function()
    doRedirect()
end)

hs.printf("!!! Aggressive Finder -> %s Redirect Active", bloomName)