-- Full Omarchy theme-catalog hot-reload, for hosts that want Neovim to track
-- the system theme (`omarchy-theme-set`) instead of a fixed colorscheme.
--
-- Omarchy's default LazyVim config gets this for free from lazy.nvim's file
-- watcher + a symlinked plugin spec (lua/plugins/theme.lua ->
-- ~/.local/state/omarchy/current/theme/neovim.lua). This config doesn't run
-- lazy.nvim, so instead: read that same generated spec file directly (it's
-- the authoritative theme-name -> colorscheme mapping Omarchy maintains) and
-- watch the state directory ourselves with vim.uv.
local M = {}

local state_dir = vim.fn.expand("~/.local/state/omarchy/current")
local theme_spec_file = state_dir .. "/theme/neovim.lua"

local transparent_groups = {
	"Normal", "NormalFloat", "FloatBorder", "Pmenu", "Terminal", "EndOfBuffer",
	"FoldColumn", "Folded", "SignColumn", "LineNr", "CursorLineNr", "NormalNC",
	"WhichKeyFloat", "TelescopeBorder", "TelescopeNormal", "TelescopePromptBorder",
	"TelescopePromptTitle", "NvimTreeNormal", "NvimTreeVertSplit", "NvimTreeEndOfBuffer",
	"NotifyINFOBody", "NotifyERRORBody", "NotifyWARNBody", "NotifyTRACEBody", "NotifyDEBUGBody",
	"NotifyINFOTitle", "NotifyERRORTitle", "NotifyWARNTitle", "NotifyTRACETitle", "NotifyDEBUGTitle",
	"NotifyINFOBorder", "NotifyERRORBorder", "NotifyWARNBorder", "NotifyTRACEBorder", "NotifyDEBUGBorder",
}

local function apply_transparency()
	for _, name in ipairs(transparent_groups) do
		local ok, hl = pcall(vim.api.nvim_get_hl, 0, { name = name, link = false })
		if ok then
			hl.bg = nil
			vim.api.nvim_set_hl(0, name, hl)
		end
	end
end

-- Pull the colorscheme name out of Omarchy's generated theme spec, e.g.:
--   return {
--     { "folke/tokyonight.nvim", priority = 1000 },
--     { "LazyVim/LazyVim", opts = { colorscheme = "tokyonight-night" } },
--   }
local function read_colorscheme()
	local chunk, err = loadfile(theme_spec_file)
	if not chunk then
		vim.notify("omarchy_theme: " .. tostring(err), vim.log.levels.WARN)
		return nil
	end

	local ok, spec = pcall(chunk)
	if not ok or type(spec) ~= "table" then
		return nil
	end

	for _, entry in ipairs(spec) do
		if entry[1] == "LazyVim/LazyVim" and entry.opts and entry.opts.colorscheme then
			return entry.opts.colorscheme
		end
	end
end

function M.reload()
	local colorscheme = read_colorscheme()
	if not colorscheme then
		return
	end

	vim.o.background = "dark"
	vim.cmd("highlight clear")
	if vim.fn.exists("syntax_on") == 1 then
		vim.cmd("syntax reset")
	end

	if not pcall(vim.cmd.colorscheme, colorscheme) then
		vim.notify("omarchy_theme: colorscheme '" .. colorscheme .. "' not found", vim.log.levels.WARN)
		return
	end

	apply_transparency()
	vim.cmd("redraw!")
end

local watching = false

-- `omarchy-theme-set` swaps the whole `current/theme` directory (rm -rf +
-- mv), so re-arm the watch after every fire or it goes stale once the old
-- inode is gone.
local function watch()
	if watching then
		return
	end
	watching = true

	local handle = vim.uv.new_fs_event()
	local function start()
		handle:start(state_dir, {}, vim.schedule_wrap(function()
			handle:stop()
			vim.defer_fn(function()
				M.reload()
				start()
			end, 150)
		end))
	end
	start()
end

function M.setup()
	M.reload()
	watch()
end

return M