package main

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"os/signal"
	"runtime"
	"slices"
	"strings"
	"sync"
	"syscall"
	"testing"
	"time"

	"git.golem15.com/golem15/summercms/modules/bonfire"
)

// captureAppRunner replaces appRunner for the test and returns a pointer to
// the argv of the last call.
func captureAppRunner(t *testing.T) *[]string {
	t.Helper()
	got := new([]string)
	prev := appRunner
	appRunner = func(ctx context.Context, argv []string, out bonfire.Output) error {
		*got = append([]string(nil), argv...)
		return nil
	}
	t.Cleanup(func() { appRunner = prev })
	return got
}

func TestDelegatedServePassesFlags(t *testing.T) {
	for _, tc := range []struct {
		args []string
		want []string
	}{
		{[]string{"serve", "--addr", ":8123"}, []string{"serve", "--addr", ":8123"}},
		{[]string{"serve", "--help"}, []string{"serve", "--help"}},
		{[]string{"serve", "-h"}, []string{"serve", "-h"}},
		{[]string{"serve", "--addr=:8123"}, []string{"serve", "--addr=:8123"}},
		{[]string{"serve", "--", "--addr", ":8123"}, []string{"serve", "--addr", ":8123"}},
	} {
		got := captureAppRunner(t)
		if out, err := runSummer(t, tc.args...); err != nil {
			t.Fatalf("%q: %v\n%s", tc.args, err, out)
		}
		if !slices.Equal(*got, tc.want) {
			t.Fatalf("%q: argv = %q, want %q", tc.args, *got, tc.want)
		}
	}
}

func TestDelegateCommandsPassArgs(t *testing.T) {
	for _, args := range [][]string{
		{"migrate:rollback", "--plugin", "acme.blog"},
		{"queue:work", "--queue", "a", "--queue", "b"},
		{"schedule:run", "--once"},
		{"queue:clear", "emails"},
		{"migrate"},
		{"migrate:status", "--help"},
		{"route:list"},
		{"key:generate"},
		{"admin:create", "--email", "you@example.com", "--superuser"},
		{"admin:reset-password", "admin@example.com"},
	} {
		got := captureAppRunner(t)
		if out, err := runSummer(t, args...); err != nil {
			t.Fatalf("%q: %v\n%s", args, err, out)
		}
		if !slices.Equal(*got, args) {
			t.Fatalf("%q: argv = %q, want %q", args, *got, args)
		}
	}
}

func TestDelegateCommandsHelp(t *testing.T) {
	hints := map[string][]string{
		"migrate:rollback": {"--plugin"},
		"queue:work":       {"--queue"},
		"schedule:run":     {"--once"},
		"serve":            {"--addr"},
		"admin:create":     {"--email", "--superuser"},
	}
	cmds := delegateCommands()
	if len(cmds) != 11 {
		t.Fatalf("delegateCommands() has %d commands, want 11", len(cmds))
	}
	got := captureAppRunner(t)
	for _, c := range cmds {
		out, err := runSummer(t, "help", c.Name)
		if err != nil {
			t.Fatalf("help %s: %v", c.Name, err)
		}
		for _, want := range append([]string{"passed to the app binary"}, hints[c.Name]...) {
			if !strings.Contains(out, want) {
				t.Fatalf("help %s missing %q:\n%s", c.Name, want, out)
			}
		}
	}
	if *got != nil {
		t.Fatalf("help ran the app binary with %q", *got)
	}

	out, err := runSummer(t, "--help")
	if err != nil {
		t.Fatal(err)
	}
	for _, c := range cmds {
		found := false
		for _, line := range strings.Split(out, "\n") {
			fields := strings.Fields(line)
			if len(fields) > 0 && fields[0] == c.Name && strings.Contains(line, "(flags pass to the app binary)") {
				found = true
				break
			}
		}
		if !found {
			t.Fatalf("summer --help does not mark %s:\n%s", c.Name, out)
		}
	}
}

// TestSignalHelperProcess is not a real test: the signal tests re-execute the
// test binary with SUMMER_SIGNAL_HELPER=1 to get a child that shuts down
// gracefully on SIGINT or SIGTERM, like the app binary's serve.
func TestSignalHelperProcess(t *testing.T) {
	if os.Getenv("SUMMER_SIGNAL_HELPER") != "1" {
		return
	}
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()
	fmt.Println("ready")
	select {
	case <-ctx.Done():
		fmt.Println("graceful shutdown")
		os.Exit(0)
	case <-time.After(20 * time.Second):
		os.Exit(3)
	}
}

// syncBuffer is a bytes.Buffer safe for the child's writes and the test's
// reads at the same time.
type syncBuffer struct {
	mu  sync.Mutex
	buf bytes.Buffer
}

func (b *syncBuffer) Write(p []byte) (int, error) {
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.buf.Write(p)
}

func (b *syncBuffer) String() string {
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.buf.String()
}

func helperArgv() []string {
	return []string{"-test.run=^TestSignalHelperProcess$"}
}

func helperEnv(cmd *exec.Cmd) {
	cmd.Env = append(os.Environ(), "SUMMER_SIGNAL_HELPER=1")
}

func waitForOutput(t *testing.T, out *syncBuffer, want string) {
	t.Helper()
	deadline := time.Now().Add(5 * time.Second)
	for !strings.Contains(out.String(), want) {
		if time.Now().After(deadline) {
			t.Fatalf("child never printed %q; output:\n%s", want, out.String())
		}
		time.Sleep(10 * time.Millisecond)
	}
}

func TestRunChildForwardsSignals(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("signal forwarding is POSIX-only")
	}
	for _, sig := range []os.Signal{os.Interrupt, syscall.SIGTERM} {
		t.Run(sig.String(), func(t *testing.T) {
			var out syncBuffer
			cmd := newAppCmd(context.Background(), os.Args[0], ".", helperArgv(), &out)
			helperEnv(cmd)
			sigs := make(chan os.Signal, 1)
			done := make(chan error, 1)
			go func() { done <- runChild(cmd, sigs) }()
			waitForOutput(t, &out, "ready")
			sigs <- sig
			select {
			case err := <-done:
				if err != nil {
					t.Fatalf("runChild: %v\n%s", err, out.String())
				}
			case <-time.After(10 * time.Second):
				t.Fatal("runChild did not return after the signal")
			}
			if !strings.Contains(out.String(), "graceful shutdown") {
				t.Fatalf("child did not shut down gracefully:\n%s", out.String())
			}
		})
	}
}

func TestNewAppCmdCancelSendsSIGTERM(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("SIGTERM is POSIX-only")
	}
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	var out syncBuffer
	cmd := newAppCmd(ctx, os.Args[0], ".", helperArgv(), &out)
	helperEnv(cmd)
	done := make(chan error, 1)
	go func() { done <- runChild(cmd, nil) }()
	waitForOutput(t, &out, "ready")
	cancel()
	select {
	case err := <-done:
		if !errors.Is(err, context.Canceled) {
			t.Fatalf("err = %v, want context.Canceled\n%s", err, out.String())
		}
	case <-time.After(10 * time.Second):
		t.Fatal("child did not exit after cancel")
	}
	if !strings.Contains(out.String(), "graceful shutdown") {
		t.Fatalf("child was not stopped with SIGTERM:\n%s", out.String())
	}
}