local process = require("@lune/process")
local stdio = require("@lune/stdio")
local task = require("@lune/task")

-- Spawning a child process should work, with options

local thread = task.delay(1, function()
	stdio.ewrite("Spawning a process should take a reasonable amount of time\n")
	task.wait(1)
	process.exit(1)
end)

local IS_WINDOWS = process.os == "windows"

local result = process.spawn(
	if IS_WINDOWS then "cmd" else "ls",
	if IS_WINDOWS then { "/c", "dir" } else { "-a" }
)

task.cancel(thread)

assert(result.ok, "Failed to spawn child process")

assert(result.stderr == "", "Stderr was not empty")
assert(result.stdout ~= "", "Stdout was empty")

assert(string.find(result.stdout, "Cargo.toml") ~= nil, "Missing Cargo.toml in output")
assert(string.find(result.stdout, ".gitignore") ~= nil, "Missing .gitignore in output")

-- It should also work the same when spawned using a shell
-- Note that the default on Windows is Powershell which has different flags / behavior

local shellResult = process.spawn("ls", {
	if IS_WINDOWS then "-Force" else "-a",
}, {
	shell = true,
})

assert(shellResult.ok, "Failed to spawn child process (shell)")

assert(shellResult.stderr == "", "Stderr was not empty (shell)")
assert(shellResult.stdout ~= "", "Stdout was empty (shell)")

assert(string.find(shellResult.stdout, "Cargo.toml") ~= nil, "Missing Cargo.toml in output (shell)")
assert(string.find(shellResult.stdout, ".gitignore") ~= nil, "Missing .gitignore in output (shell)")

local pwdCommand = if IS_WINDOWS then "cmd" else "pwd"
local pwdArgs = if IS_WINDOWS then { "/c", "cd" } else {}

-- Make sure the cwd option actually uses the directory we want
local rootPwd = process.spawn(pwdCommand, pwdArgs, {
	cwd = "/",
}).stdout
rootPwd = string.gsub(rootPwd, "^%s+", "")
rootPwd = string.gsub(rootPwd, "%s+$", "")

-- Windows: <Drive Letter>:\, Unix: /
local expectedRootPwd = if IS_WINDOWS then string.sub(rootPwd, 1, 1) .. ":\\" else "/"
if rootPwd ~= expectedRootPwd then
	error(
		string.format(
			"Current working directory for child process was not set correctly!"
				.. "\nExpected '%s', got '%s'",
			expectedRootPwd,
			rootPwd
		)
	)
end

-- Setting cwd should not change the cwd of this process

local pwdBefore = process.spawn(pwdCommand, pwdArgs).stdout
process.spawn("ls", {}, {
	cwd = "/",
	shell = true,
})
local pwdAfter = process.spawn(pwdCommand, pwdArgs).stdout
assert(pwdBefore == pwdAfter, "Current working directory changed after running child process")

--[[
	Setting the cwd on a child process should properly
	replace any leading ~ with the users real home dir
]]

local homeDir1 = process.spawn("echo $HOME", nil, {
	shell = true,
}).stdout

-- Powershell for windows uses `$pwd.Path` instead of `pwd` as pwd would return a PathInfo object,
-- using $pwd.Path gets the Path property of the PathInfo object.
local homeDir2 = process.spawn(if IS_WINDOWS then "$pwd.Path" else "pwd", nil, {
	shell = true,
	cwd = "~",
}).stdout

assert(#homeDir1 > 0, "Home dir from echo was empty")
assert(#homeDir2 > 0, "Home dir from pwd was empty")
assert(homeDir1 == homeDir2, "Home dirs did not match when performing tilde substitution")

--[[
	Spawning a process should not block any lua thread(s)

	We test this by sleeping more than once concurrently
	and then ensuring that the total time slept is more
	than a single sleep but also less than 1.5 sleeps
]]

local SLEEP_DURATION = 1 / 4
local SLEEP_SAMPLES = 2

-- Unfortunately we
local thread2 = task.delay(30, function()
	stdio.ewrite("Spawning a sleep process should take a reasonable amount of time\n")
	task.wait(1)
	process.exit(1)
end)

local sleepStart = os.clock()
local sleepCounter = 0
for i = 1, SLEEP_SAMPLES, 1 do
	task.spawn(function()
		local args = {
			-- Sleep command on Windows in Seconds has some weird behavior with decimals ...
			tostring(SLEEP_DURATION * (IS_WINDOWS and 1000 or 1)),
		}
		if IS_WINDOWS then
			-- ... so we use milliseconds instead.
			table.insert(args, 1, "-Milliseconds")
		end
		-- Windows does not have `sleep` as a process, so we use powershell instead.
		process.spawn("sleep", args, if IS_WINDOWS then { shell = true } else nil)
		sleepCounter += 1
	end)
end
while sleepCounter < SLEEP_SAMPLES do
	task.wait()
end

task.cancel(thread2)

assert(
	(os.clock() - sleepStart) >= SLEEP_DURATION,
	"Spawning a process that does blocking sleep did not sleep enough"
)

-- Inheriting stdio & environment variables should work

local echoMessage = "Hello from child process!"
local echoResult = process.spawn("echo", {
	if IS_WINDOWS then '"$Env:TEST_VAR"' else '"$TEST_VAR"',
}, {
	env = { TEST_VAR = echoMessage },
	shell = if IS_WINDOWS then "powershell" else "bash",
	stdio = "inherit",
})

-- Windows echo adds \r\n (CRLF) and unix adds \n (LF)
local trailingAddition = if IS_WINDOWS then "\r\n" else "\n"
assert(
	echoResult.stdout == (echoMessage .. trailingAddition),
	"Inheriting stdio did not return proper output"
)