// 脚本运行时探测与本地执行 — 适配 ./aiops 单二进制 / Docker 容器环境 // Logan.Li
package scriptrunner

import (
	"bytes"
	"context"
	"fmt"
	"os"
	"os/exec"
	"runtime"
	"time"
)

// RuntimeInfo 当前主机可用的脚本解释器
type RuntimeInfo struct {
	Shell       bool   `json:"shell"`
	ShellPath   string `json:"shell_path,omitempty"`
	Python      bool   `json:"python"`
	PythonPath  string `json:"python_path,omitempty"`
	PowerShell  bool   `json:"powershell"`
	PowerShellPath string `json:"powershell_path,omitempty"`
	OS          string `json:"os"`
	Arch        string `json:"arch"`
	EmbedMode   bool   `json:"embed_mode"` // 单二进制 embed 部署
}

// DetectRuntime 探测 bash/sh、python3、powershell 是否可用 // Logan.Li
func DetectRuntime() RuntimeInfo {
	info := RuntimeInfo{
		OS:        runtime.GOOS,
		Arch:      runtime.GOARCH,
		EmbedMode: true,
	}
	for _, p := range []string{"/bin/bash", "/usr/bin/bash", "bash"} {
		if path, ok := lookExecutable(p); ok {
			info.Shell = true
			info.ShellPath = path
			break
		}
	}
	if !info.Shell {
		for _, p := range []string{"/bin/sh", "/usr/bin/sh", "sh"} {
			if path, ok := lookExecutable(p); ok {
				info.Shell = true
				info.ShellPath = path
				break
			}
		}
	}
	for _, p := range []string{"/usr/bin/python3", "/usr/local/bin/python3", "python3"} {
		if path, ok := lookExecutable(p); ok {
			info.Python = true
			info.PythonPath = path
			break
		}
	}
	for _, p := range []string{"/usr/bin/pwsh", "/usr/local/bin/pwsh", "pwsh", "powershell"} {
		if path, ok := lookExecutable(p); ok {
			info.PowerShell = true
			info.PowerShellPath = path
			break
		}
	}
	return info
}

func lookExecutable(name string) (string, bool) {
	path, err := exec.LookPath(name)
	if err != nil {
		return "", false
	}
	return path, true
}

// CanRun 判断指定脚本类型是否可在本机执行 // Logan.Li
func CanRun(rt RuntimeInfo, scriptType string) (bool, string) {
	switch scriptType {
	case "shell", "bash", "command", "":
		if rt.Shell {
			return true, ""
		}
		return false, "当前环境未找到 bash/sh，无法执行 Shell 脚本（Docker 镜像需安装 bash）"
	case "python":
		if rt.Python {
			return true, ""
		}
		return false, "当前环境未找到 python3，无法执行 Python 脚本（请在镜像中安装 python3）"
	case "powershell":
		if rt.PowerShell {
			return true, ""
		}
		return false, "当前环境未找到 PowerShell (pwsh)，无法执行 PowerShell 脚本"
	default:
		return false, fmt.Sprintf("不支持的脚本类型: %s", scriptType)
	}
}

// Run 在 AIOps 本机执行脚本，返回合并输出、退出码、耗时(ms) // Logan.Li
func Run(scriptType, content string, timeoutSec int) (output string, exitCode int, durationMs int, err error) {
	rt := DetectRuntime()
	ok, reason := CanRun(rt, scriptType)
	if !ok {
		return reason + "\n", -1, 0, fmt.Errorf("%s", reason)
	}

	start := time.Now()
	timeout := time.Duration(timeoutSec) * time.Second
	if timeout <= 0 {
		timeout = 300 * time.Second
	}
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	var cmd *exec.Cmd
	switch scriptType {
	case "python":
		py := rt.PythonPath
		if py == "" {
			py = "python3"
		}
		cmd = exec.CommandContext(ctx, py, "-c", content)
	case "powershell":
		pwsh := rt.PowerShellPath
		if pwsh == "" {
			pwsh = "pwsh"
		}
		cmd = exec.CommandContext(ctx, pwsh, "-NoProfile", "-NonInteractive", "-Command", content)
	default:
		sh := rt.ShellPath
		if sh == "" {
			sh = "bash"
		}
		cmd = exec.CommandContext(ctx, sh, "-c", content)
	}

	var out bytes.Buffer
	cmd.Stdout = &out
	cmd.Stderr = &out
	cmd.Env = os.Environ()

	runErr := cmd.Run()
	durationMs = int(time.Since(start).Milliseconds())
	output = out.String()

	if ctx.Err() == context.DeadlineExceeded {
		output += fmt.Sprintf("\n[超时] 执行超过 %d 秒被终止", timeoutSec)
		return output, -1, durationMs, ctx.Err()
	}
	if runErr != nil {
		if exitError, ok := runErr.(*exec.ExitError); ok {
			exitCode = exitError.ExitCode()
		} else {
			exitCode = -1
			output += "\n" + runErr.Error()
		}
		return output, exitCode, durationMs, runErr
	}
	return output, 0, durationMs, nil
}