// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package net

import (
	"flag"
	"fmt"
	"net/internal/socktest"
	"os"
	"runtime"
	"sort"
	"strings"
	"sync"
	"testing"
)

var (
	sw socktest.Switch

	// uninstallTestHooks runs just before a run of benchmarks.
	testHookUninstaller sync.Once
)

var (
	// Do not test datagrams with empty payload by default.
	// It depends on each platform implementation whether generic
	// read, socket recv system calls return the result of zero
	// byte read.
	testDatagram = flag.Bool("datagram", false, "whether to test UDP and unixgram")

	testDNSFlood = flag.Bool("dnsflood", false, "whether to test DNS query flooding")

	testExternal = flag.Bool("external", true, "allow use of external networks during long test")

	// If external IPv4 connectivity exists, we can try dialing
	// non-node/interface local scope IPv4 addresses.
	testIPv4 = flag.Bool("ipv4", true, "assume external IPv4 connectivity exists")

	// If external IPv6 connectivity exists, we can try dialing
	// non-node/interface local scope IPv6 addresses.
	testIPv6 = flag.Bool("ipv6", false, "assume external IPv6 connectivity exists")

	// BUG: TestDialError has been broken, and so this flag
	// exists. We should fix the test and remove this flag soon.
	runErrorTest = flag.Bool("run_error_test", false, "let TestDialError check for DNS errors")
)

func TestMain(m *testing.M) {
	setupTestData()
	installTestHooks()

	st := m.Run()

	testHookUninstaller.Do(func() { uninstallTestHooks() })
	if !testing.Short() {
		printLeakedGoroutines()
		printLeakedSockets()
		printSocketStats()
	}
	forceCloseSockets()
	os.Exit(st)
}

func setupTestData() {
	if supportsIPv4 {
		resolveTCPAddrTests = append(resolveTCPAddrTests, []resolveTCPAddrTest{
			{"tcp", "localhost:1", &TCPAddr{IP: IPv4(127, 0, 0, 1), Port: 1}, nil},
			{"tcp4", "localhost:2", &TCPAddr{IP: IPv4(127, 0, 0, 1), Port: 2}, nil},
		}...)
		resolveUDPAddrTests = append(resolveUDPAddrTests, []resolveUDPAddrTest{
			{"udp", "localhost:1", &UDPAddr{IP: IPv4(127, 0, 0, 1), Port: 1}, nil},
			{"udp4", "localhost:2", &UDPAddr{IP: IPv4(127, 0, 0, 1), Port: 2}, nil},
		}...)
		resolveIPAddrTests = append(resolveIPAddrTests, []resolveIPAddrTest{
			{"ip", "localhost", &IPAddr{IP: IPv4(127, 0, 0, 1)}, nil},
			{"ip4", "localhost", &IPAddr{IP: IPv4(127, 0, 0, 1)}, nil},
		}...)
	}

	if supportsIPv6 {
		resolveTCPAddrTests = append(resolveTCPAddrTests, resolveTCPAddrTest{"tcp6", "localhost:3", &TCPAddr{IP: IPv6loopback, Port: 3}, nil})
		resolveUDPAddrTests = append(resolveUDPAddrTests, resolveUDPAddrTest{"udp6", "localhost:3", &UDPAddr{IP: IPv6loopback, Port: 3}, nil})
		resolveIPAddrTests = append(resolveIPAddrTests, resolveIPAddrTest{"ip6", "localhost", &IPAddr{IP: IPv6loopback}, nil})
	}

	if ifi := loopbackInterface(); ifi != nil {
		index := fmt.Sprintf("%v", ifi.Index)
		resolveTCPAddrTests = append(resolveTCPAddrTests, []resolveTCPAddrTest{
			{"tcp6", "[fe80::1%" + ifi.Name + "]:1", &TCPAddr{IP: ParseIP("fe80::1"), Port: 1, Zone: zoneToString(ifi.Index)}, nil},
			{"tcp6", "[fe80::1%" + index + "]:2", &TCPAddr{IP: ParseIP("fe80::1"), Port: 2, Zone: index}, nil},
		}...)
		resolveUDPAddrTests = append(resolveUDPAddrTests, []resolveUDPAddrTest{
			{"udp6", "[fe80::1%" + ifi.Name + "]:1", &UDPAddr{IP: ParseIP("fe80::1"), Port: 1, Zone: zoneToString(ifi.Index)}, nil},
			{"udp6", "[fe80::1%" + index + "]:2", &UDPAddr{IP: ParseIP("fe80::1"), Port: 2, Zone: index}, nil},
		}...)
		resolveIPAddrTests = append(resolveIPAddrTests, []resolveIPAddrTest{
			{"ip6", "fe80::1%" + ifi.Name, &IPAddr{IP: ParseIP("fe80::1"), Zone: zoneToString(ifi.Index)}, nil},
			{"ip6", "fe80::1%" + index, &IPAddr{IP: ParseIP("fe80::1"), Zone: index}, nil},
		}...)
	}
}

func printLeakedGoroutines() {
	gss := leakedGoroutines()
	if len(gss) == 0 {
		return
	}
	fmt.Fprintf(os.Stderr, "Leaked goroutines:\n")
	for _, gs := range gss {
		fmt.Fprintf(os.Stderr, "%v\n", gs)
	}
	fmt.Fprintf(os.Stderr, "\n")
}

// leakedGoroutines returns a list of remaining goroutines used in
// test cases.
func leakedGoroutines() []string {
	var gss []string
	b := make([]byte, 2<<20)
	b = b[:runtime.Stack(b, true)]
	for _, s := range strings.Split(string(b), "\n\n") {
		ss := strings.SplitN(s, "\n", 2)
		if len(ss) != 2 {
			continue
		}
		stack := strings.TrimSpace(ss[1])
		if !strings.Contains(stack, "created by net") {
			continue
		}
		gss = append(gss, stack)
	}
	sort.Strings(gss)
	return gss
}

func printLeakedSockets() {
	sos := sw.Sockets()
	if len(sos) == 0 {
		return
	}
	fmt.Fprintf(os.Stderr, "Leaked sockets:\n")
	for s, so := range sos {
		fmt.Fprintf(os.Stderr, "%v: %+v\n", s, so)
	}
	fmt.Fprintf(os.Stderr, "\n")
}

func printSocketStats() {
	sts := sw.Stats()
	if len(sts) == 0 {
		return
	}
	fmt.Fprintf(os.Stderr, "Socket statistical information:\n")
	for _, st := range sts {
		fmt.Fprintf(os.Stderr, "%+v\n", st)
	}
	fmt.Fprintf(os.Stderr, "\n")
}