package main

import (
	"bufio"
	"bytes"
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"time"
)

type AgentConfig struct {
	APIBase string
	AgentKey string
	Token string
	PollMS time.Duration
}

type HeartbeatResponse struct {
	OK bool `json:"ok"`
	Control struct {
		Enabled bool `json:"enabled"`
		MonitoringEnabled bool `json:"monitoringEnabled"`
		LogIngestEnabled bool `json:"logIngestEnabled"`
		ProactivePushEnabled bool `json:"proactivePushEnabled"`
		HeartbeatIntervalMs int `json:"heartbeatIntervalMs"`
	} `json:"control"`
}

type ClaimResponse struct {
	Job *Job `json:"job"`
}

type Job struct {
	RunID string `json:"runId"`
	TraceID string `json:"traceId"`
	TargetID string `json:"targetId"`
	TargetName string `json:"targetName"`
	ServiceKey string `json:"serviceKey"`
	Type string `json:"type"`
	Endpoint string `json:"endpoint"`
	Config map[string]any `json:"config"`
}

type ResultPayload struct {
	Status string `json:"status"`
	ErrorTag *string `json:"errorTag"`
	Summary string `json:"summary"`
	FailureReason *string `json:"failureReason"`
	Metrics map[string]any `json:"metrics"`
	Details map[string]any `json:"details"`
	LogExcerpt *string `json:"logExcerpt"`
}

func main() {
	cfg, err := loadConfig()
	if err != nil {
		fmt.Fprintln(os.Stderr, "load config failed:", err)
		os.Exit(1)
	}
	if err := loop(cfg); err != nil {
		fmt.Fprintln(os.Stderr, "agent loop failed:", err)
		os.Exit(1)
	}
}

func loadConfig() (*AgentConfig, error) {
	loadEnvFile("agent-config.env")
	apiBase := strings.TrimRight(envOr("MONITORING_API_BASE_URL", "http://127.0.0.1:3001"), "/")
	agentKey := strings.TrimSpace(envOr("MONITORING_AGENT_KEY", ""))
	token := strings.TrimSpace(envOr("MONITORING_AGENT_TOKEN", ""))
	if agentKey == "" || token == "" {
		return nil, errors.New("MONITORING_AGENT_KEY and MONITORING_AGENT_TOKEN are required")
	}
	pollValue := envOr("MONITORING_AGENT_POLL_MS", "10000")
	pollMS, err := strconv.Atoi(strings.TrimSpace(pollValue))
	if err != nil || pollMS <= 0 {
		pollMS = 10000
	}
	return &AgentConfig{
		APIBase: apiBase,
		AgentKey: agentKey,
		Token: token,
		PollMS: time.Duration(pollMS) * time.Millisecond,
	}, nil
}

func loop(cfg *AgentConfig) error {
	client := &http.Client{Timeout: 15 * time.Second}
	sleepFor := cfg.PollMS
	for {
		heartbeat, err := heartbeat(client, cfg)
		if err != nil {
			fmt.Fprintln(os.Stderr, "heartbeat failed:", err)
			time.Sleep(sleepFor)
			continue
		}
		if heartbeat.Control.HeartbeatIntervalMs > 0 {
			sleepFor = time.Duration(heartbeat.Control.HeartbeatIntervalMs) * time.Millisecond
		}
		if !heartbeat.Control.Enabled || !heartbeat.Control.MonitoringEnabled {
			time.Sleep(sleepFor)
			continue
		}
		claim, err := claimJob(client, cfg)
		if err != nil {
			fmt.Fprintln(os.Stderr, "claim job failed:", err)
			time.Sleep(sleepFor)
			continue
		}
		if claim.Job == nil {
			time.Sleep(sleepFor)
			continue
		}
		result := executeJob(claim.Job)
		if err := submitResult(client, cfg, claim.Job.RunID, result); err != nil {
			fmt.Fprintln(os.Stderr, "submit result failed:", err)
		}
	}
}

func heartbeat(client *http.Client, cfg *AgentConfig) (*HeartbeatResponse, error) {
	payload := map[string]any{
		"agentKey": cfg.AgentKey,
		"host": hostname(),
		"platform": runtime.GOOS,
		"version": "host-agent-go-0.1",
		"meta": map[string]any{"arch": runtime.GOARCH},
	}
	var response HeartbeatResponse
	if err := doJSON(client, cfg, http.MethodPost, "/api/monitoring/agent/heartbeat", payload, &response); err != nil {
		return nil, err
	}
	return &response, nil
}

func claimJob(client *http.Client, cfg *AgentConfig) (*ClaimResponse, error) {
	payload := map[string]any{"agentKey": cfg.AgentKey}
	var response ClaimResponse
	if err := doJSON(client, cfg, http.MethodPost, "/api/monitoring/agent/jobs/claim", payload, &response); err != nil {
		return nil, err
	}
	return &response, nil
}

func submitResult(client *http.Client, cfg *AgentConfig, runID string, result ResultPayload) error {
	return doJSON(client, cfg, http.MethodPost, "/api/monitoring/agent/jobs/"+runID+"/result", result, nil)
}

func doJSON(client *http.Client, cfg *AgentConfig, method, path string, payload any, out any) error {
	var body io.Reader
	if payload != nil {
		raw, err := json.Marshal(payload)
		if err != nil {
			return err
		}
		body = bytes.NewReader(raw)
	}
	req, err := http.NewRequestWithContext(context.Background(), method, cfg.APIBase+path, body)
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-monitoring-agent-token", cfg.Token)
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return err
	}
	if resp.StatusCode >= 400 {
		return fmt.Errorf("HTTP_%d: %s", resp.StatusCode, strings.TrimSpace(string(data)))
	}
	if out != nil && len(data) > 0 {
		if err := json.Unmarshal(data, out); err != nil {
			return err
		}
	}
	return nil
}

func executeJob(job *Job) ResultPayload {
	switch job.Type {
	case "tcp":
		return executeTCPJob(job)
	case "redis":
		return executeRedisJob(job)
	case "rabbitmq":
		return executeRabbitMQJob(job)
	case "elasticsearch":
		return executeESJob(job)
	case "java-app":
		return executeJavaJob(job)
	default:
		return executeHTTPJob(job)
	}
}

func executeHTTPJob(job *Job) ResultPayload {
	client := &http.Client{Timeout: timeoutFor(job.Config, 8*time.Second)}
	req, err := http.NewRequest(http.MethodGet, job.Endpoint, nil)
	if err != nil {
		return failed("HTTP_CHECK_FAILED", "HTTP 检测失败", err.Error(), nil, map[string]any{"endpoint": job.Endpoint})
	}
	applyBasicAuth(req, job.Config)
	resp, err := client.Do(req)
	if err != nil {
		return failed("HTTP_CHECK_FAILED", "HTTP 检测失败", err.Error(), nil, map[string]any{"endpoint": job.Endpoint})
	}
	defer resp.Body.Close()
	body, _ := io.ReadAll(io.LimitReader(resp.Body, 64*1024))
	if resp.StatusCode >= 200 && resp.StatusCode < 400 {
		return success("HTTP 目标检测通过", map[string]any{"statusCode": resp.StatusCode, "responseBytes": len(body)}, map[string]any{"endpoint": job.Endpoint, "bodyPreview": string(body)})
	}
	return failed("HTTP_CHECK_FAILED", "HTTP 目标检测失败", fmt.Sprintf("HTTP_%d", resp.StatusCode), map[string]any{"statusCode": resp.StatusCode}, map[string]any{"endpoint": job.Endpoint, "bodyPreview": string(body)})
}

func executeTCPJob(job *Job) ResultPayload {
	host := stringValue(job.Config, "tcpHost", job.Endpoint)
	port := intValue(job.Config, "tcpPort", 0)
	if host == "" || port == 0 {
		return failed("TCP_CONFIG_INVALID", "TCP 检测失败", "tcpHost / tcpPort 未配置", nil, nil)
	}
	timeout := timeoutFor(job.Config, 5*time.Second)
	conn, err := net.DialTimeout("tcp", net.JoinHostPort(host, strconv.Itoa(port)), timeout)
	if err != nil {
		return failed("TCP_CONNECT_FAILED", "TCP 端口不可达", err.Error(), map[string]any{"host": host, "port": port}, nil)
	}
	_ = conn.Close()
	return success("TCP 端口连通", map[string]any{"host": host, "port": port}, nil)
}

func executeRedisJob(job *Job) ResultPayload {
	host := stringValue(job.Config, "tcpHost", job.Endpoint)
	port := intValue(job.Config, "tcpPort", 6379)
	timeout := timeoutFor(job.Config, 5*time.Second)
	conn, err := net.DialTimeout("tcp", net.JoinHostPort(host, strconv.Itoa(port)), timeout)
	if err != nil {
		return failed("REDIS_CONNECT_FAILED", "Redis 检测失败", err.Error(), map[string]any{"host": host, "port": port}, nil)
	}
	defer conn.Close()
	_ = conn.SetDeadline(time.Now().Add(timeout))
	if password := stringValue(job.Config, "authPassword", ""); password != "" {
		if _, err := conn.Write([]byte(respCommand("AUTH", password))); err != nil {
			return failed("REDIS_AUTH_FAILED", "Redis 检测失败", err.Error(), nil, nil)
		}
		if _, err := readRedisReply(conn); err != nil {
			return failed("REDIS_AUTH_FAILED", "Redis 检测失败", err.Error(), nil, nil)
		}
	}
	if _, err := conn.Write([]byte(respCommand("PING"))); err != nil {
		return failed("REDIS_PING_FAILED", "Redis 检测失败", err.Error(), nil, nil)
	}
	pingReply, err := readRedisReply(conn)
	if err != nil || !strings.Contains(strings.ToUpper(pingReply), "PONG") {
		return failed("REDIS_PING_FAILED", "Redis 检测失败", safeErr(err, "PING 未返回 PONG"), nil, nil)
	}
	if _, err := conn.Write([]byte(respCommand("INFO"))); err != nil {
		return failed("REDIS_INFO_FAILED", "Redis 检测失败", err.Error(), nil, nil)
	}
	infoText, err := readRedisReply(conn)
	if err != nil {
		return failed("REDIS_INFO_FAILED", "Redis 检测失败", err.Error(), nil, nil)
	}
	info := parseRedisInfo(infoText)
	return success("Redis 检测通过", map[string]any{
		"host": host,
		"port": port,
		"role": info["role"],
		"usedMemory": info["used_memory"],
		"connectedClients": info["connected_clients"],
	}, map[string]any{"infoPreview": trimMap(info, 30)})
}

func executeRabbitMQJob(job *Job) ResultPayload {
	client := &http.Client{Timeout: timeoutFor(job.Config, 8*time.Second)}
	overview, err := fetchJSON(client, job.Endpoint, stringValue(job.Config, "rabbitmqOverviewPath", "/api/overview"), job.Config)
	if err != nil {
		return failed("RABBITMQ_REQUEST_FAILED", "RabbitMQ 检测失败", err.Error(), nil, nil)
	}
	queues, err := fetchJSON(client, job.Endpoint, stringValue(job.Config, "rabbitmqQueuesPath", "/api/queues"), job.Config)
	if err != nil {
		return failed("RABBITMQ_REQUEST_FAILED", "RabbitMQ 检测失败", err.Error(), nil, nil)
	}
	nodes, err := fetchJSON(client, job.Endpoint, stringValue(job.Config, "rabbitmqNodesPath", "/api/nodes"), job.Config)
	if err != nil {
		return failed("RABBITMQ_REQUEST_FAILED", "RabbitMQ 检测失败", err.Error(), nil, nil)
	}
	return success("RabbitMQ 管理接口检测通过", map[string]any{
		"queueCount": arrayLen(queues),
		"nodeCount": arrayLen(nodes),
	}, map[string]any{
		"overview": overview,
		"queuePreview": firstItems(queues, 10),
		"nodePreview": firstItems(nodes, 10),
	})
}

func executeESJob(job *Job) ResultPayload {
	client := &http.Client{Timeout: timeoutFor(job.Config, 8*time.Second)}
	health, err := fetchJSON(client, job.Endpoint, stringValue(job.Config, "elasticsearchHealthPath", "/_cluster/health"), job.Config)
	if err != nil {
		return failed("ES_REQUEST_FAILED", "Elasticsearch 检测失败", err.Error(), nil, nil)
	}
	nodes, err := fetchJSON(client, job.Endpoint, stringValue(job.Config, "elasticsearchNodesPath", "/_nodes/stats"), job.Config)
	if err != nil {
		return failed("ES_REQUEST_FAILED", "Elasticsearch 检测失败", err.Error(), nil, nil)
	}
	healthMap, _ := health.(map[string]any)
	clusterStatus := strings.ToLower(fmt.Sprintf("%v", healthMap["status"]))
	ok := clusterStatus == "green" || clusterStatus == "yellow"
	if ok {
		return success("Elasticsearch 集群检测通过", map[string]any{
			"clusterStatus": clusterStatus,
			"nodeCount": healthMap["number_of_nodes"],
		}, map[string]any{"health": health, "nodesPreview": nodes})
	}
	return failed("ES_CLUSTER_UNHEALTHY", "Elasticsearch 集群异常", "cluster status="+clusterStatus, map[string]any{"clusterStatus": clusterStatus}, map[string]any{"health": health})
}

func executeJavaJob(job *Job) ResultPayload {
	processMode := strings.ToLower(stringValue(job.Config, "processMatchMode", "command"))
	processValue := strings.TrimSpace(stringValue(job.Config, "processMatchValue", ""))
	if processValue == "" {
		return failed("JAVA_CONFIG_INVALID", "Java 程序监测失败", "processMatchValue 未配置", nil, nil)
	}

	var pid string
	var commandLine string
	if processMode == "pid" {
		pid = processValue
		commandLine = processValue
	} else {
		out, err := runCommand("ps", "-eww", "-o", "pid=,command=")
		if err != nil {
			return failed("PROCESS_DISCOVERY_FAILED", "Java 程序监测失败", err.Error(), nil, nil)
		}
		pid, commandLine = findJavaProcess(out, processValue)
		if pid == "" {
			return failed("JAVA_PROCESS_NOT_FOUND", "Java 程序监测失败", "未找到匹配的 Java 进程", map[string]any{"keyword": processValue}, nil)
		}
	}

	details := map[string]any{
		"process": map[string]any{"pid": pid, "commandLine": commandLine},
		"agentKey": stringValue(job.Config, "agentKey", ""),
	}
	metrics := map[string]any{"pid": pid, "host": hostname()}

	if jcmdPath := firstExistingExecutable(stringValue(job.Config, "jcmdPath", ""), "/usr/bin/jcmd", "/bin/jcmd"); jcmdPath != "" {
		results := map[string]string{}
		for _, cmd := range stringSlice(job.Config, "jcmdCommands", []string{"VM.command_line", "GC.heap_info"}) {
			out, err := runCommand(jcmdPath, pid, cmd)
			results[cmd] = strings.TrimSpace(safeErr(err, out))
		}
		details["jcmd"] = results
	}

	if jstatPath := firstExistingExecutable(stringValue(job.Config, "jstatPath", ""), "/usr/bin/jstat", "/bin/jstat"); jstatPath != "" {
		results := map[string]string{}
		for _, option := range stringSlice(job.Config, "jstatOptions", []string{"-gcutil"}) {
			out, err := runCommand(jstatPath, option, pid)
			results[option] = strings.TrimSpace(safeErr(err, out))
		}
		details["jstat"] = results
		metrics["jstatCollected"] = true
	}

	var logExcerpt *string
	if logPath := stringValue(job.Config, "logFilePath", ""); logPath != "" {
		tailLines := intValue(job.Config, "logTailLines", 120)
		pattern := stringValue(job.Config, "logKeyword", "ERROR|WARN|Exception|Timeout|Refused")
		excerpt := buildLogExcerpt(logPath, tailLines, pattern)
		if excerpt != "" {
			logExcerpt = &excerpt
		}
	}

	return ResultPayload{
		Status: "success",
		ErrorTag: nil,
		Summary: "宿主机 Agent 已完成 Java 程序监测",
		FailureReason: nil,
		Metrics: metrics,
		Details: details,
		LogExcerpt: logExcerpt,
	}
}

func fetchJSON(client *http.Client, base, path string, config map[string]any) (any, error) {
	u, err := url.Parse(base)
	if err != nil {
		return nil, err
	}
	relative, err := url.Parse(path)
	if err != nil {
		return nil, err
	}
	target := u.ResolveReference(relative)
	req, err := http.NewRequest(http.MethodGet, target.String(), nil)
	if err != nil {
		return nil, err
	}
	applyBasicAuth(req, config)
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 400 {
		body, _ := io.ReadAll(io.LimitReader(resp.Body, 16*1024))
		return nil, fmt.Errorf("HTTP_%d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
	}
	var payload any
	if err := json.NewDecoder(resp.Body).Decode(&payload); err != nil {
		return nil, err
	}
	return payload, nil
}

func applyBasicAuth(req *http.Request, config map[string]any) {
	username := stringValue(config, "authUsername", "")
	password := stringValue(config, "authPassword", "")
	if username == "" || password == "" {
		return
	}
	token := base64.StdEncoding.EncodeToString([]byte(username + ":" + password))
	req.Header.Set("Authorization", "Basic "+token)
}

func buildLogExcerpt(logPath string, tailLines int, pattern string) string {
	if tailLines <= 0 {
		tailLines = 120
	}
	content, err := os.ReadFile(filepath.Clean(logPath))
	if err != nil {
		return ""
	}
	lines := strings.Split(string(content), "\n")
	start := 0
	if len(lines) > tailLines {
		start = len(lines) - tailLines
	}
	window := lines[start:]
	if pattern == "" {
		return strings.TrimSpace(strings.Join(window, "\n"))
	}
	re, err := regexp.Compile(pattern)
	if err != nil {
		return strings.TrimSpace(strings.Join(window, "\n"))
	}
	filtered := make([]string, 0, len(window))
	for _, line := range window {
		if re.MatchString(line) {
			filtered = append(filtered, line)
		}
	}
	if len(filtered) == 0 {
		return strings.TrimSpace(strings.Join(window, "\n"))
	}
	return strings.TrimSpace(strings.Join(filtered, "\n"))
}

func firstExistingExecutable(paths ...string) string {
	for _, candidate := range paths {
		candidate = strings.TrimSpace(candidate)
		if candidate == "" {
			continue
		}
		if _, err := os.Stat(candidate); err == nil {
			return candidate
		}
	}
	return ""
}

func findJavaProcess(psOutput, keyword string) (string, string) {
	loweredKeyword := strings.ToLower(strings.TrimSpace(keyword))
	scanner := bufio.NewScanner(strings.NewReader(psOutput))
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		loweredLine := strings.ToLower(line)
		if line == "" || !strings.Contains(loweredLine, "java") || !strings.Contains(loweredLine, loweredKeyword) {
			continue
		}
		parts := strings.Fields(line)
		if len(parts) < 2 {
			continue
		}
		return parts[0], strings.TrimSpace(strings.TrimPrefix(line, parts[0]))
	}
	return "", ""
}

func runCommand(name string, args ...string) (string, error) {
	cmd := exec.Command(name, args...)
	output, err := cmd.CombinedOutput()
	return string(output), err
}

func loadEnvFile(path string) {
	content, err := os.ReadFile(path)
	if err != nil {
		return
	}
	for _, line := range strings.Split(string(content), "\n") {
		trimmed := strings.TrimSpace(line)
		if trimmed == "" || strings.HasPrefix(trimmed, "#") {
			continue
		}
		index := strings.Index(trimmed, "=")
		if index < 0 {
			continue
		}
		key := strings.TrimSpace(trimmed[:index])
		value := strings.TrimSpace(trimmed[index+1:])
		if os.Getenv(key) == "" {
			_ = os.Setenv(key, value)
		}
	}
}

func envOr(key, fallback string) string {
	if value := strings.TrimSpace(os.Getenv(key)); value != "" {
		return value
	}
	return fallback
}

func stringValue(config map[string]any, key, fallback string) string {
	if config == nil {
		return fallback
	}
	value, ok := config[key]
	if !ok || value == nil {
		return fallback
	}
	return strings.TrimSpace(fmt.Sprintf("%v", value))
}

func intValue(config map[string]any, key string, fallback int) int {
	if config == nil {
		return fallback
	}
	value, ok := config[key]
	if !ok || value == nil {
		return fallback
	}
	switch typed := value.(type) {
	case float64:
		return int(typed)
	case int:
		return typed
	case string:
		parsed, err := strconv.Atoi(strings.TrimSpace(typed))
		if err == nil {
			return parsed
		}
	}
	return fallback
}

func stringSlice(config map[string]any, key string, fallback []string) []string {
	if config == nil {
		return fallback
	}
	value, ok := config[key]
	if !ok || value == nil {
		return fallback
	}
	switch typed := value.(type) {
	case []any:
		result := make([]string, 0, len(typed))
		for _, item := range typed {
			text := strings.TrimSpace(fmt.Sprintf("%v", item))
			if text != "" {
				result = append(result, text)
			}
		}
		if len(result) > 0 {
			return result
		}
	case []string:
		if len(typed) > 0 {
			return typed
		}
	}
	return fallback
}

func timeoutFor(config map[string]any, fallback time.Duration) time.Duration {
	ms := intValue(config, "timeoutMs", 0)
	if ms > 0 {
		return time.Duration(ms) * time.Millisecond
	}
	return fallback
}

func respCommand(parts ...string) string {
	var builder strings.Builder
	builder.WriteString("*")
	builder.WriteString(strconv.Itoa(len(parts)))
	builder.WriteString("\r\n")
	for _, part := range parts {
		builder.WriteString("$")
		builder.WriteString(strconv.Itoa(len(part)))
		builder.WriteString("\r\n")
		builder.WriteString(part)
		builder.WriteString("\r\n")
	}
	return builder.String()
}

func readRedisReply(conn net.Conn) (string, error) {
	reader := bufio.NewReader(conn)
	prefix, err := reader.ReadByte()
	if err != nil {
		return "", err
	}
	line, err := reader.ReadString('\n')
	if err != nil {
		return "", err
	}
	switch prefix {
	case '+', '-', ':':
		return strings.TrimSpace(line), nil
	case '$':
		size, err := strconv.Atoi(strings.TrimSpace(line))
		if err != nil || size < 0 {
			return "", errors.New("invalid bulk string size")
		}
		buf := make([]byte, size+2)
		if _, err := io.ReadFull(reader, buf); err != nil {
			return "", err
		}
		return string(buf[:size]), nil
	default:
		return strings.TrimSpace(line), nil
	}
}

func parseRedisInfo(info string) map[string]any {
	result := map[string]any{}
	for _, line := range strings.Split(info, "\n") {
		line = strings.TrimSpace(line)
		if line == "" || strings.HasPrefix(line, "#") || !strings.Contains(line, ":") {
			continue
		}
		parts := strings.SplitN(line, ":", 2)
		key := parts[0]
		value := parts[1]
		if n, err := strconv.ParseInt(value, 10, 64); err == nil {
			result[key] = n
		} else {
			result[key] = value
		}
	}
	return result
}

func trimMap(input map[string]any, limit int) map[string]any {
	output := map[string]any{}
	count := 0
	for key, value := range input {
		output[key] = value
		count++
		if count >= limit {
			break
		}
	}
	return output
}

func firstItems(value any, limit int) any {
	items, ok := value.([]any)
	if !ok {
		return value
	}
	if len(items) <= limit {
		return items
	}
	return items[:limit]
}

func arrayLen(value any) int {
	items, ok := value.([]any)
	if !ok {
		return 0
	}
	return len(items)
}

func hostname() string {
	name, err := os.Hostname()
	if err != nil {
		return "unknown"
	}
	return name
}

func success(summary string, metrics, details map[string]any) ResultPayload {
	if metrics == nil {
		metrics = map[string]any{}
	}
	if details == nil {
		details = map[string]any{}
	}
	return ResultPayload{
		Status: "success",
		ErrorTag: nil,
		Summary: summary,
		FailureReason: nil,
		Metrics: metrics,
		Details: details,
		LogExcerpt: nil,
	}
}

func failed(tag, summary, reason string, metrics, details map[string]any) ResultPayload {
	if metrics == nil {
		metrics = map[string]any{}
	}
	if details == nil {
		details = map[string]any{}
	}
	return ResultPayload{
		Status: "failed",
		ErrorTag: ptr(tag),
		Summary: summary,
		FailureReason: ptr(reason),
		Metrics: metrics,
		Details: details,
		LogExcerpt: nil,
	}
}

func ptr[T any](value T) *T {
	return &value
}

func safeErr(err error, fallback string) string {
	if err != nil {
		return err.Error()
	}
	return fallback
}