//go:build integration

package test

import (
	"context"
	"fmt"
	"os"
	"os/exec"
	"strconv"
	"strings"
	"time"
)

// TargetConfig configures an iSCSI target instance.
type TargetConfig struct {
	VolSize string // e.g. "100M"
	WALSize string // e.g. "64M" (default), "4M" for WAL pressure tests
	IQN     string
	Port    int
}

// DefaultTargetConfig returns a default target config for integration tests.
func DefaultTargetConfig() TargetConfig {
	return TargetConfig{
		VolSize: "100M",
		WALSize: "64M",
		IQN:     "iqn.2024.com.seaweedfs:test1",
		Port:    3260,
	}
}

// Target manages the lifecycle of an iscsi-target process on a remote node.
type Target struct {
	node    *Node
	config  TargetConfig
	binPath string // remote path to iscsi-target binary
	pid     int
	logFile string // remote path to target's stderr log
	volFile string // remote path to volume file
}

// NewTarget creates a Target bound to a node.
func NewTarget(node *Node, config TargetConfig) *Target {
	return &Target{
		node:    node,
		config:  config,
		binPath: "/tmp/iscsi-target-test",
		volFile: "/tmp/blockvol-test.blk",
		logFile: "/tmp/iscsi-target-test.log",
	}
}

// Build cross-compiles the iscsi-target binary for linux/amd64.
// Uses Windows Go with GOOS=linux (no WSL Go dependency).
func (t *Target) Build(ctx context.Context, repoDir string) error {
	binDir := repoDir + "/weed/storage/blockvol/iscsi/cmd/iscsi-target"
	outPath := repoDir + "/iscsi-target-linux"

	cmd := exec.CommandContext(ctx, "go", "build", "-o", outPath, ".")
	cmd.Dir = binDir
	cmd.Env = append(os.Environ(), "GOOS=linux", "GOARCH=amd64", "CGO_ENABLED=0")
	out, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("build failed: %s\n%w", out, err)
	}
	return nil
}

// Deploy uploads the pre-built binary to the target node.
func (t *Target) Deploy(localBin string) error {
	return t.node.Upload(localBin, t.binPath)
}

// Start launches the target process. If create is true, a new volume is created.
func (t *Target) Start(ctx context.Context, create bool) error {
	// Remove old log
	t.node.Run(ctx, fmt.Sprintf("rm -f %s", t.logFile))

	args := fmt.Sprintf("-vol %s -addr :%d -iqn %s",
		t.volFile, t.config.Port, t.config.IQN)

	if create {
		// Remove old volume file
		t.node.Run(ctx, fmt.Sprintf("rm -f %s %s.wal", t.volFile, t.volFile))
		args += fmt.Sprintf(" -create -size %s", t.config.VolSize)
	}

	// setsid -f creates a new session so the process survives when
	// the parent shell (wsl -e bash -c) exits. We discover the PID
	// after startup via ps + grep.
	cmd := fmt.Sprintf("setsid -f %s %s >%s 2>&1", t.binPath, args, t.logFile)
	_, stderr, code, err := t.node.Run(ctx, cmd)
	if err != nil || code != 0 {
		return fmt.Errorf("start target: code=%d stderr=%s err=%v", code, stderr, err)
	}

	// Wait for port first, then discover PID
	if err := t.WaitForPort(ctx); err != nil {
		return err
	}

	// Discover PID by matching the binary name
	stdout, _, _, _ := t.node.Run(ctx, fmt.Sprintf("ps -eo pid,args | grep '%s' | grep -v grep | awk '{print $1}'", t.binPath))
	pidStr := strings.TrimSpace(stdout)
	// Take first line if multiple matches
	if idx := strings.IndexByte(pidStr, '\n'); idx > 0 {
		pidStr = pidStr[:idx]
	}
	pid, err := strconv.Atoi(pidStr)
	if err != nil {
		return fmt.Errorf("find target PID: %q: %w", pidStr, err)
	}
	t.pid = pid
	return nil
}

// Stop sends SIGTERM, waits up to 10s, then Kill9.
func (t *Target) Stop(ctx context.Context) error {
	if t.pid == 0 {
		return nil
	}

	// SIGTERM
	t.node.Run(ctx, fmt.Sprintf("kill %d", t.pid))

	// Wait up to 10s for exit
	deadline := time.Now().Add(10 * time.Second)
	for time.Now().Before(deadline) {
		_, _, code, _ := t.node.Run(ctx, fmt.Sprintf("kill -0 %d 2>/dev/null", t.pid))
		if code != 0 {
			t.pid = 0
			return nil
		}
		time.Sleep(500 * time.Millisecond)
	}

	// Force kill
	return t.Kill9()
}

// Kill9 sends SIGKILL immediately.
func (t *Target) Kill9() error {
	if t.pid == 0 {
		return nil
	}
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	t.node.Run(ctx, fmt.Sprintf("kill -9 %d", t.pid))
	t.pid = 0
	return nil
}

// Restart stops the target and starts it again (preserving the volume).
func (t *Target) Restart(ctx context.Context) error {
	if err := t.Stop(ctx); err != nil {
		return fmt.Errorf("restart stop: %w", err)
	}
	return t.Start(ctx, false)
}

// WaitForPort polls until the target port is listening.
func (t *Target) WaitForPort(ctx context.Context) error {
	for {
		select {
		case <-ctx.Done():
			return fmt.Errorf("wait for port %d: %w", t.config.Port, ctx.Err())
		default:
		}

		stdout, _, code, _ := t.node.Run(ctx, fmt.Sprintf("ss -tln | grep :%d", t.config.Port))
		if code == 0 && strings.Contains(stdout, fmt.Sprintf(":%d", t.config.Port)) {
			return nil
		}
		time.Sleep(200 * time.Millisecond)
	}
}

// CollectLog downloads the target's log file contents.
func (t *Target) CollectLog() (string, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	stdout, _, _, err := t.node.Run(ctx, fmt.Sprintf("cat %s 2>/dev/null", t.logFile))
	if err != nil {
		return "", err
	}
	return stdout, nil
}

// Cleanup removes the volume file, WAL, and log from the target node.
func (t *Target) Cleanup(ctx context.Context) {
	t.node.Run(ctx, fmt.Sprintf("rm -f %s %s.wal %s", t.volFile, t.volFile, t.logFile))
}

// PID returns the current target process ID.
func (t *Target) PID() int { return t.pid }

// VolFilePath returns the remote volume file path.
func (t *Target) VolFilePath() string { return t.volFile }