---@brief
---
--- https://github.com/rust-lang/rust-analyzer
---
--- rust-analyzer (aka rls 2.0), a language server for Rust
---
---
--- See [docs](https://rust-analyzer.github.io/book/configuration.html) for extra settings. The settings can be used like this:
--- ```lua
--- vim.lsp.config('rust_analyzer', {
---   settings = {
---     ['rust-analyzer'] = {
---       diagnostics = {
---         enable = false;
---       }
---     }
---   }
--- })
--- ```
---
--- Note: do not set `init_options` for this LS config, it will be automatically populated by the contents of settings["rust-analyzer"] per
--- https://github.com/rust-lang/rust-analyzer/blob/eb5da56d839ae0a9e9f50774fa3eb78eb0964550/docs/dev/lsp-extensions.md?plain=1#L26.

local function reload_workspace(bufnr)
	local clients = vim.lsp.get_clients({ bufnr = bufnr, name = "rust_analyzer" })
	for _, client in ipairs(clients) do
		client.request(client, "rust-analyzer/reloadWorkspace", nil, function(err)
			if err then
				error(tostring(err))
			end
		end, 0)
	end
end

local function is_library(fname)
	local user_home = vim.fs.normalize(vim.env.HOME)
	local cargo_home = os.getenv("CARGO_HOME") or user_home .. "/.cargo"
	local registry = cargo_home .. "/registry/src"
	local git_registry = cargo_home .. "/git/checkouts"

	local rustup_home = os.getenv("RUSTUP_HOME") or user_home .. "/.rustup"
	local toolchains = rustup_home .. "/toolchains"

	for _, item in ipairs({ toolchains, registry, git_registry }) do
		if vim.fs.relpath(item, fname) then
			local clients = vim.lsp.get_clients({ name = "rust_analyzer" })
			return #clients > 0 and clients[#clients].config.root_dir or nil
		end
	end
end

vim.lsp.config("rust-analyzer", {
	cmd = { "rust-analyzer" },
	filetypes = { "rust" },
	root_dir = function(bufnr, on_dir)
		local fname = vim.api.nvim_buf_get_name(bufnr)
		local reused_dir = is_library(fname)
		if reused_dir then
			on_dir(reused_dir)
			return
		end

		local cargo_crate_dir = vim.fs.root(fname, { "Cargo.toml" })
		local cargo_workspace_root

		if cargo_crate_dir == nil then
			on_dir(
				vim.fs.root(fname, { "rust-project.json" })
					or vim.fs.dirname(vim.fs.find(".git", { path = fname, upward = true })[1])
			)
			return
		end

		local cmd = {
			"cargo",
			"metadata",
			"--no-deps",
			"--format-version",
			"1",
			"--manifest-path",
			cargo_crate_dir .. "/Cargo.toml",
		}

		vim.system(cmd, { text = true }, function(output)
			if output.code == 0 then
				if output.stdout then
					local result = vim.json.decode(output.stdout)
					if result["workspace_root"] then
						cargo_workspace_root = vim.fs.normalize(result["workspace_root"])
					end
				end

				on_dir(cargo_workspace_root or cargo_crate_dir)
			else
				vim.schedule(function()
					vim.notify(
						("[rust_analyzer] cmd failed with code %d: %s\n%s"):format(output.code, cmd, output.stderr)
					)
				end)
			end
		end)
	end,
	capabilities = {
		experimental = {
			serverStatusNotification = true,
		},
	},
	on_attach = function(_, bufnr)
		vim.api.nvim_buf_create_user_command(bufnr, "LspCargoReload", function()
			reload_workspace(bufnr)
		end, { desc = "Reload current cargo workspace" })

		-- -- autocommand to reload cargo workspace on save
		-- vim.api.nvim_create_autocmd('BufWritePost', {
		--   desc = 'Reload Current Cargo Workspace',
		--   group = vim.api.nvim_create_augroup('cargo-reload', { clear = true }),
		--   pattern = {'*.rs'},
		--   callback = function()
		--     vim.notify('Reloading Cargo Workspace')
		--     reload_workspace(bufnr)
		--     vim.notify('Cargo workspace reloaded')
		--   end,
		-- })
	end,
})
