vim.api.nvim_create_user_command("Jopen", function(opts)
	local revset = #opts.fargs > 0 and opts.fargs[1] or "@"

	-- Get the files changed by given revset
	local output =
		vim.fn.system(string.format("jj diff --name-only --revisions %s 2>/dev/null", vim.fn.shellescape(revset)))
	local ok = vim.v.shell_error == 0
	if not ok then
		vim.notify(string.format("Error getting diff of revset: %s", revset), vim.log.levels.ERROR, { title = "JJ" })
		return
	end

	-- Split the output into lines and open each file
	for file in output:gmatch("[^\r\n]+") do
		local buf
		if vim.fn.bufexists(file) ~= 0 then
			buf = vim.fn.bufnr(file)
		else
			buf = vim.fn.bufadd(file)
		end
		-- Explanation: loading many buffers here causes slow down and even Git errors in Neo-tree
		-- so let any needed loading happen whenever the user browses the buffers.
		-- if not vim.api.nvim_buf_is_loaded(buf) then
		-- 	vim.fn.bufload(buf)
		-- end
		vim.api.nvim_set_option_value("buflisted", true, { buf = buf })
	end
end, { desc = "Open files changed by given revset", nargs = "?" })

vim.api.nvim_create_user_command("Jclose", function(opts)
	local revset = #opts.fargs > 0 and opts.fargs[1] or "@"

	local output =
		vim.fn.system(string.format("jj diff --name-only --revisions %s 2>/dev/null", vim.fn.shellescape(revset)))
	local ok = vim.v.shell_error == 0
	if not ok then
		vim.notify(string.format("Error getting diff of revset: %s", revset), vim.log.levels.ERROR, { title = "JJ" })
		return
	end

	-- Split the output into lines and close each file
	for file in output:gmatch("[^\r\n]+") do
		local buf
		if vim.fn.bufexists(file) ~= 0 then
			vim.api.nvim_buf_delete(vim.fn.bufnr(file), { force = false, unload = false })
		end
	end

	-- Refresh Neo-tree of buffers
	local manager = require("neo-tree.sources.manager")
	local utils = require("neo-tree.utils")
	local refresh = utils.wrap(manager.refresh, "buffers")
	refresh()
end, { desc = "Close buffers for files changed by given revset", nargs = "?" })

vim.api.nvim_create_user_command("Jview", function(opts)
	local left
	local right
	local utils = require("jj.utils")
	if #opts.fargs <= 1 then
		if #opts.fargs == 0 then
			left = "@-"
			right = "@"
		else
			left, right = string.gmatch(opts.fargs[1], "([^.]+)[.][.](.+)$")()
		end
		if left == nil then
			-- FixMe(completeness): does not work on merge commits
			left = string.format("%s-", opts.fargs[1])
			right = opts.fargs[1]
		else
		end
		left = utils.get_commit_id(left)
		right = utils.get_commit_id(right)
		vim.cmd(string.format("DiffviewOpen %s..%s", left, right))
	elseif #opts.fargs == 2 then
		left = utils.get_commit_id(opts.fargs[1])
		right = utils.get_commit_id(opts.fargs[2])
		vim.cmd(string.format("DiffviewFileHistory --range=%s...%s --right-only --no-merges", left, right))
	end
end, {
	desc = "Diff a revset and its parent (must be single), a revset range, or show history between two revsets",
	nargs = "*",
})