package framework

import (
	"bufio"
	"bytes"
	"errors"
	"fmt"
	"io"
	"net"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/seaweedfs/seaweedfs/test/testutil"
	"github.com/seaweedfs/seaweedfs/test/volume_server/matrix"
)

const (
	defaultWaitTimeout    = 30 * time.Second
	defaultWaitTick       = 200 * time.Millisecond
	testVolumeSizeLimitMB = 32
)

var (
	weedBinaryOnce sync.Once
	weedBinaryPath string
	weedBinaryErr  error
)

// Cluster is a lightweight SeaweedFS master + one volume server test harness.
type Cluster struct {
	testingTB testing.TB
	profile   matrix.Profile

	weedBinary string
	baseDir    string
	configDir  string
	logsDir    string
	keepLogs   bool

	masterPort     int
	masterGrpcPort int
	volumePort     int
	volumeGrpcPort int
	volumePubPort  int

	masterCmd *exec.Cmd
	volumeCmd *exec.Cmd

	volumeDataDirs []string

	cleanupOnce sync.Once
}

// StartSingleVolumeCluster boots one master and one volume server.
func StartSingleVolumeCluster(t testing.TB, profile matrix.Profile) *Cluster {
	return StartSingleVolumeClusterWithDataDirs(t, profile, 1)
}

// StartSingleVolumeClusterWithDataDirs boots one master and one volume server
// with dataDirCount separate data directories (passed to -dir as a comma list).
// Each directory becomes its own DiskLocation on the volume server, letting
// tests exercise multi-disk EC placement paths.
func StartSingleVolumeClusterWithDataDirs(t testing.TB, profile matrix.Profile, dataDirCount int) *Cluster {
	t.Helper()
	if dataDirCount < 1 {
		t.Fatalf("dataDirCount must be >= 1, got %d", dataDirCount)
	}

	weedBinary, err := FindOrBuildWeedBinary()
	if err != nil {
		t.Fatalf("resolve weed binary: %v", err)
	}

	baseDir, keepLogs, err := newWorkDir()
	if err != nil {
		t.Fatalf("create temp test directory: %v", err)
	}

	configDir := filepath.Join(baseDir, "config")
	logsDir := filepath.Join(baseDir, "logs")
	masterDataDir := filepath.Join(baseDir, "master")
	volumeDataDirs := make([]string, dataDirCount)
	// Single-dir layout stays at baseDir/volume so existing fixtures
	// (CorruptDatFile etc.) that hardcode that path keep working. Only
	// multi-dir clusters get the "volumeN" layout.
	for i := 0; i < dataDirCount; i++ {
		if dataDirCount == 1 {
			volumeDataDirs[i] = filepath.Join(baseDir, "volume")
		} else {
			volumeDataDirs[i] = filepath.Join(baseDir, fmt.Sprintf("volume%d", i))
		}
	}
	setupDirs := append([]string{configDir, logsDir, masterDataDir}, volumeDataDirs...)
	for _, dir := range setupDirs {
		if mkErr := os.MkdirAll(dir, 0o755); mkErr != nil {
			t.Fatalf("create %s: %v", dir, mkErr)
		}
	}

	if err = writeSecurityConfig(configDir, profile); err != nil {
		t.Fatalf("write security config: %v", err)
	}

	miniPorts, ports, err := testutil.AllocatePortSet(1, 3)
	if err != nil {
		t.Fatalf("allocate ports: %v", err)
	}
	masterPort := miniPorts[0]
	masterGrpcPort := masterPort + testutil.GrpcPortOffset

	c := &Cluster{
		testingTB:      t,
		profile:        profile,
		weedBinary:     weedBinary,
		baseDir:        baseDir,
		configDir:      configDir,
		logsDir:        logsDir,
		keepLogs:       keepLogs,
		masterPort:     masterPort,
		masterGrpcPort: masterGrpcPort,
		volumePort:     ports[0],
		volumeGrpcPort: ports[1],
		volumePubPort:  ports[0],
	}
	if profile.SplitPublicPort {
		c.volumePubPort = ports[2]
	}

	if err = c.startMaster(masterDataDir); err != nil {
		c.Stop()
		t.Fatalf("start master: %v", err)
	}
	if err = c.waitForHTTP(c.MasterURL() + "/dir/status"); err != nil {
		masterLog := c.tailLog("master.log")
		c.Stop()
		t.Fatalf("wait for master readiness: %v\nmaster log tail:\n%s", err, masterLog)
	}

	if err = c.startVolume(volumeDataDirs); err != nil {
		masterLog := c.tailLog("master.log")
		c.Stop()
		t.Fatalf("start volume: %v\nmaster log tail:\n%s", err, masterLog)
	}
	c.volumeDataDirs = volumeDataDirs
	if err = c.waitForHTTP(c.VolumeAdminURL() + "/status"); err != nil {
		volumeLog := c.tailLog("volume.log")
		c.Stop()
		t.Fatalf("wait for volume readiness: %v\nvolume log tail:\n%s", err, volumeLog)
	}
	if err = c.waitForTCP(c.VolumeGRPCAddress()); err != nil {
		volumeLog := c.tailLog("volume.log")
		c.Stop()
		t.Fatalf("wait for volume grpc readiness: %v\nvolume log tail:\n%s", err, volumeLog)
	}

	t.Cleanup(func() {
		c.Stop()
	})

	return c
}

// Stop terminates all processes and cleans temporary files.
func (c *Cluster) Stop() {
	if c == nil {
		return
	}
	c.cleanupOnce.Do(func() {
		stopProcess(c.volumeCmd)
		stopProcess(c.masterCmd)
		if !c.keepLogs && !c.testingTB.Failed() {
			_ = os.RemoveAll(c.baseDir)
		} else if c.baseDir != "" {
			c.testingTB.Logf("volume server integration logs kept at %s", c.baseDir)
		}
	})
}

// RestartVolumeServer kills the volume server and starts a new one against
// the same data dirs and ports. The master keeps running. The previous run's
// volume.log is moved to volume.log.previous so the first run's logs survive
// a second-run startup failure.
func (c *Cluster) RestartVolumeServer() {
	c.testingTB.Helper()
	stopProcess(c.volumeCmd)
	c.volumeCmd = nil
	// Rotate the log; absent on the first call after a clean start, which
	// is fine — startVolume will create it. Any real filesystem failure
	// surfaces immediately on the next os.Create in startVolume.
	oldLog := filepath.Join(c.logsDir, "volume.log")
	_ = os.Rename(oldLog, filepath.Join(c.logsDir, "volume.log.previous"))
	if err := c.startVolume(c.volumeDataDirs); err != nil {
		c.testingTB.Fatalf("restart volume server: %v", err)
	}
	if err := c.waitForHTTP(c.VolumeAdminURL() + "/status"); err != nil {
		c.testingTB.Fatalf("wait for volume admin readiness after restart: %v\nvolume log tail:\n%s", err, c.tailLog("volume.log"))
	}
	if err := c.waitForTCP(c.VolumeGRPCAddress()); err != nil {
		c.testingTB.Fatalf("wait for volume grpc readiness after restart: %v\nvolume log tail:\n%s", err, c.tailLog("volume.log"))
	}
}

// StopVolumeServer kills the volume server but leaves the master and data
// dirs alone. Pair with RestartVolumeServer or Stop.
func (c *Cluster) StopVolumeServer() {
	c.testingTB.Helper()
	stopProcess(c.volumeCmd)
	c.volumeCmd = nil
}

func (c *Cluster) startMaster(dataDir string) error {
	logFile, err := os.Create(filepath.Join(c.logsDir, "master.log"))
	if err != nil {
		return err
	}

	args := []string{
		"-config_dir=" + c.configDir,
		"master",
		"-ip=127.0.0.1",
		"-port=" + strconv.Itoa(c.masterPort),
		"-port.grpc=" + strconv.Itoa(c.masterGrpcPort),
		"-mdir=" + dataDir,
		"-peers=none",
		"-volumeSizeLimitMB=" + strconv.Itoa(testVolumeSizeLimitMB),
		"-defaultReplication=000",
	}

	c.masterCmd = exec.Command(c.weedBinary, args...)
	c.masterCmd.Dir = c.baseDir
	c.masterCmd.Stdout = logFile
	c.masterCmd.Stderr = logFile
	return c.masterCmd.Start()
}

func (c *Cluster) startVolume(dataDirs []string) error {
	logFile, err := os.Create(filepath.Join(c.logsDir, "volume.log"))
	if err != nil {
		return err
	}

	maxPerDir := make([]string, len(dataDirs))
	for i := range dataDirs {
		maxPerDir[i] = "16"
	}
	args := []string{
		"-config_dir=" + c.configDir,
		"volume",
		"-ip=127.0.0.1",
		"-port=" + strconv.Itoa(c.volumePort),
		"-port.grpc=" + strconv.Itoa(c.volumeGrpcPort),
		"-port.public=" + strconv.Itoa(c.volumePubPort),
		"-dir=" + strings.Join(dataDirs, ","),
		"-max=" + strings.Join(maxPerDir, ","),
		"-master=127.0.0.1:" + strconv.Itoa(c.masterPort),
		"-readMode=" + c.profile.ReadMode,
		"-concurrentUploadLimitMB=" + strconv.Itoa(c.profile.ConcurrentUploadLimitMB),
		"-concurrentDownloadLimitMB=" + strconv.Itoa(c.profile.ConcurrentDownloadLimitMB),
		// Integration tests deliberately exercise loopback S3 endpoints
		// (the test rig boots weed-mini next to the volume server); allow
		// the SSRF guard to be bypassed for them.
		"-volume.allowUntrustedRemoteEndpoints",
	}
	if c.profile.InflightUploadTimeout > 0 {
		args = append(args, "-inflightUploadDataTimeout="+c.profile.InflightUploadTimeout.String())
	}
	if c.profile.InflightDownloadTimeout > 0 {
		args = append(args, "-inflightDownloadDataTimeout="+c.profile.InflightDownloadTimeout.String())
	}

	c.volumeCmd = exec.Command(c.weedBinary, args...)
	c.volumeCmd.Dir = c.baseDir
	c.volumeCmd.Stdout = logFile
	c.volumeCmd.Stderr = logFile
	return c.volumeCmd.Start()
}

func (c *Cluster) waitForHTTP(url string) error {
	client := &http.Client{Timeout: 1 * time.Second}
	deadline := time.Now().Add(defaultWaitTimeout)
	for time.Now().Before(deadline) {
		resp, err := client.Get(url)
		if err == nil {
			_, _ = io.Copy(io.Discard, resp.Body)
			resp.Body.Close()
			if resp.StatusCode < 500 {
				return nil
			}
		}
		time.Sleep(defaultWaitTick)
	}
	return fmt.Errorf("timed out waiting for %s", url)
}

func (c *Cluster) waitForTCP(addr string) error {
	deadline := time.Now().Add(defaultWaitTimeout)
	for time.Now().Before(deadline) {
		conn, err := net.DialTimeout("tcp", addr, time.Second)
		if err == nil {
			_ = conn.Close()
			return nil
		}
		time.Sleep(defaultWaitTick)
	}
	return fmt.Errorf("timed out waiting for tcp %s", addr)
}

func stopProcess(cmd *exec.Cmd) {
	if cmd == nil || cmd.Process == nil {
		return
	}

	_ = cmd.Process.Signal(os.Interrupt)
	done := make(chan error, 1)
	go func() {
		done <- cmd.Wait()
	}()

	select {
	case <-time.After(10 * time.Second):
		_ = cmd.Process.Kill()
		<-done
	case <-done:
	}
}

func newWorkDir() (dir string, keepLogs bool, err error) {
	keepLogs = os.Getenv("VOLUME_SERVER_IT_KEEP_LOGS") == "1"
	dir, err = os.MkdirTemp("", "seaweedfs_volume_server_it_")
	return dir, keepLogs, err
}

func writeSecurityConfig(configDir string, profile matrix.Profile) error {
	var b strings.Builder
	if profile.EnableJWT {
		if profile.JWTSigningKey == "" || profile.JWTReadKey == "" {
			return errors.New("jwt profile requires both write and read keys")
		}
		b.WriteString("[jwt.signing]\n")
		b.WriteString("key = \"")
		b.WriteString(profile.JWTSigningKey)
		b.WriteString("\"\n")
		b.WriteString("expires_after_seconds = 60\n\n")

		b.WriteString("[jwt.signing.read]\n")
		b.WriteString("key = \"")
		b.WriteString(profile.JWTReadKey)
		b.WriteString("\"\n")
		b.WriteString("expires_after_seconds = 60\n")
	}
	if profile.EnableUIAccess {
		if b.Len() > 0 {
			b.WriteString("\n")
		}
		b.WriteString("[access]\n")
		b.WriteString("ui = true\n")
	}
	if b.Len() == 0 {
		b.WriteString("# optional security config generated for integration tests\n")
	}
	return os.WriteFile(filepath.Join(configDir, "security.toml"), []byte(b.String()), 0o644)
}

// FindOrBuildWeedBinary returns an executable weed binary, building one when needed.
func FindOrBuildWeedBinary() (string, error) {
	if fromEnv := os.Getenv("WEED_BINARY"); fromEnv != "" {
		if isExecutableFile(fromEnv) {
			return fromEnv, nil
		}
		return "", fmt.Errorf("WEED_BINARY is set but not executable: %s", fromEnv)
	}

	weedBinaryOnce.Do(func() {
		repoRoot := ""
		if _, file, _, ok := runtime.Caller(0); ok {
			repoRoot = filepath.Clean(filepath.Join(filepath.Dir(file), "..", "..", ".."))
		}
		if repoRoot == "" {
			weedBinaryErr = errors.New("unable to detect repository root")
			return
		}

		binDir := filepath.Join(os.TempDir(), "seaweedfs_volume_server_it_bin")
		if err := os.MkdirAll(binDir, 0o755); err != nil {
			weedBinaryErr = fmt.Errorf("create binary directory %s: %w", binDir, err)
			return
		}
		binPath := filepath.Join(binDir, "weed")

		cmd := exec.Command("go", "build", "-o", binPath, ".")
		cmd.Dir = filepath.Join(repoRoot, "weed")
		var out bytes.Buffer
		cmd.Stdout = &out
		cmd.Stderr = &out
		if err := cmd.Run(); err != nil {
			weedBinaryErr = fmt.Errorf("build weed binary: %w\n%s", err, out.String())
			return
		}
		if !isExecutableFile(binPath) {
			weedBinaryErr = fmt.Errorf("built weed binary is not executable: %s", binPath)
			return
		}
		weedBinaryPath = binPath
	})

	if weedBinaryErr != nil {
		return "", weedBinaryErr
	}
	return weedBinaryPath, nil
}

func isExecutableFile(path string) bool {
	info, err := os.Stat(path)
	if err != nil || info.IsDir() {
		return false
	}
	mode := info.Mode().Perm()
	return mode&0o111 != 0
}

func (c *Cluster) tailLog(logName string) string {
	f, err := os.Open(filepath.Join(c.logsDir, logName))
	if err != nil {
		return ""
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)
	lines := make([]string, 0, 40)
	for scanner.Scan() {
		lines = append(lines, scanner.Text())
		if len(lines) > 40 {
			lines = lines[1:]
		}
	}
	return strings.Join(lines, "\n")
}

func (c *Cluster) MasterAddress() string {
	return net.JoinHostPort("127.0.0.1", strconv.Itoa(c.masterPort))
}

func (c *Cluster) VolumeAdminAddress() string {
	return net.JoinHostPort("127.0.0.1", strconv.Itoa(c.volumePort))
}

func (c *Cluster) VolumePublicAddress() string {
	return net.JoinHostPort("127.0.0.1", strconv.Itoa(c.volumePubPort))
}

func (c *Cluster) VolumeGRPCAddress() string {
	return net.JoinHostPort("127.0.0.1", strconv.Itoa(c.volumeGrpcPort))
}

// VolumeServerAddress returns SeaweedFS server address format: ip:httpPort.grpcPort
func (c *Cluster) VolumeServerAddress() string {
	return fmt.Sprintf("%s.%d", c.VolumeAdminAddress(), c.volumeGrpcPort)
}

func (c *Cluster) MasterURL() string {
	return "http://" + c.MasterAddress()
}

func (c *Cluster) VolumeAdminURL() string {
	return "http://" + c.VolumeAdminAddress()
}

func (c *Cluster) VolumePublicURL() string {
	return "http://" + c.VolumePublicAddress()
}

func (c *Cluster) BaseDir() string {
	return c.baseDir
}

// VolumeDataDirs returns the data directories the volume server was started with.
// Index 0 corresponds to DiskLocation 0, index 1 to DiskLocation 1, and so on.
// Tests can scan these directories to verify where files physically landed.
func (c *Cluster) VolumeDataDirs() []string {
	return append([]string(nil), c.volumeDataDirs...)
}