package services

import (
	"bufio"
	"cmii-uav-watchdog-common/models"
	"fmt"
	"os"
	"strings"
)

// NewCPUInfo 创建一个默认的 CPUInfo
func NewCPUInfo() models.CPUInfo {
	return models.CPUInfo{
		ModelName:    "unknown",
		Cores:        0,
		Architecture: "unknown",
		UUID:         "unknown",
	}
}

const (
	exePath        = "/proc/self/exe"
	elfMagic       = 0x7f
	elfMagicString = "ELF"
	eMachineOffset = 18
)

// parseLine 解析单行 CPU 信息
func parseLine(line string, cpuInfo *models.CPUInfo) {
	if strings.HasPrefix(line, "model name") {
		cpuInfo.ModelName = strings.TrimSpace(strings.Split(line, ":")[1])
	}
}

// getCPUCores 通过 processor 行获取 CPU 核心数
func getCPUCores() (int, error) {
	cores := 0
	file, err := os.Open("/proc/cpuinfo")
	if err != nil {
		return cores, err
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		if strings.HasPrefix(line, "processor") {
			cores++
		}
	}

	if err := scanner.Err(); err != nil {
		return cores, err
	}

	return cores, nil
}

// getCPUUUID 获取 CPU UUID
func getCPUUUID() (string, error) {
	data, err := os.ReadFile("/sys/class/dmi/id/product_uuid")
	if err != nil {
		return "unknown", err
	}
	return strings.TrimSpace(string(data)), nil
}

func getCPUArchitecture() string {
	cpuarch := "unknown"

	// 打开当前进程的执行文件
	file, err := os.Open(exePath)
	if err != nil {
		_, _ = fmt.Fprintf(os.Stderr, "Error opening %s: %v\n", exePath, err)
		return cpuarch
	}
	defer file.Close()

	// 读取前64个字节以获取 ELF 头部信息
	header := make([]byte, 64)
	if _, err := file.Read(header); err != nil {
		_, _ = fmt.Fprintf(os.Stderr, "Error reading header: %v\n", err)
		return cpuarch
	}

	// 检查 ELF 文件标识
	if header[0] != elfMagic || string(header[1:4]) != elfMagicString {
		_, _ = fmt.Fprintln(os.Stderr, "File is not an ELF file")
		return cpuarch
	}

	// 获取架构信息
	arch := header[eMachineOffset] // e_machine 字段的偏移量
	switch arch {
	case 0x02: // EM_386
		cpuarch = "x86(32-bit)"
	case 0x03: // EM_X86_64
		cpuarch = "x86_64(64-bit)"
	case 0x28: // EM_ARM
		cpuarch = "ARM"
	case 0x2A: // EM_ARM64
		cpuarch = "ARM64"
	case 0x08: // EM_MIPS
		cpuarch = "MIPS"
	default:
		cpuarch = "unknown architecture"
	}

	return cpuarch
}

// GetCPUInfo 获取 CPU 信息
func GetCPUInfo() models.CPUInfo {
	cpuInfo := NewCPUInfo()

	// 读取 /proc/cpuinfo
	file, err := os.Open("/proc/cpuinfo")
	if err != nil {
		fmt.Println("Error opening /proc/cpuinfo:", err)
		return cpuInfo // 返回默认值
	}
	defer func() {
		if err := file.Close(); err != nil {
			fmt.Println("Error closing /proc/cpuinfo:", err)
		}
	}()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		parseLine(scanner.Text(), &cpuInfo)
	}
	if err := scanner.Err(); err != nil {
		fmt.Println("Error reading /proc/cpuinfo:", err)
		return cpuInfo // 返回默认值
	}

	// 获取 CPU 核心数
	cores, err := getCPUCores()
	if err != nil {
		fmt.Println("Error getting CPU cores:", err)
	} else {
		cpuInfo.Cores = cores
	}

	// 获取 CPU UUID
	uuid, err := getCPUUUID()
	if err != nil {
		fmt.Println("Error getting CPU UUID:", err)
	} else {
		cpuInfo.UUID = uuid
	}

	cpuInfo.Architecture = getCPUArchitecture()

	return cpuInfo
}

/*
CPU模型名称: Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
核心数量: 4
架构信息: x86_64

*/