package cloud

import (
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"sort"
	"strings"
	"sync"
	"time"
)

// HuaweiProvider 通过华为云 AK/SK 签名 API 同步项目区域与 ECS 实例。 // Logan.Li
type HuaweiProvider struct {
	accessKey, secretKey string
	regionMu             sync.RWMutex
	regionByProject      map[string]string
}

// NewHuaweiProvider 创建华为云 Provider。 // Logan.Li
func NewHuaweiProvider(accessKey, secretKey string) *HuaweiProvider {
	return &HuaweiProvider{accessKey: accessKey, secretKey: secretKey, regionByProject: make(map[string]string)}
}

// Name 返回华为云厂商标识。 // Logan.Li
func (p *HuaweiProvider) Name() string { return "huawei" }

// signedGet 使用 SDK-HMAC-SHA256 调用华为云 GET API。 // Logan.Li
func (p *HuaweiProvider) signedGet(rawURL, _ string) ([]byte, error) {
	u, err := http.NewRequest(http.MethodGet, rawURL, nil)
	if err != nil {
		return nil, fmt.Errorf("创建华为云请求失败: %w", err)
	}
	now := time.Now().UTC().Format("20060102T150405Z")
	host := u.URL.Host
	canonicalHeaders := "host:" + host + "\n" + "x-sdk-date:" + now + "\n"
	signedHeaders := "host;x-sdk-date"
	canonicalURI := u.URL.EscapedPath()
	if !strings.HasSuffix(canonicalURI, "/") {
		canonicalURI += "/"
	}
	canonicalRequest := "GET\n" + canonicalURI + "\n" + u.URL.Query().Encode() + "\n" + canonicalHeaders + "\n" + signedHeaders + "\n" + sha256Hex("")
	stringToSign := "SDK-HMAC-SHA256\n" + now + "\n" + sha256Hex(canonicalRequest)
	signature := hex.EncodeToString(hmacSHA256([]byte(p.secretKey), stringToSign))
	u.Header.Set("X-Sdk-Date", now)
	u.Header.Set("Authorization", "SDK-HMAC-SHA256 Access="+p.accessKey+", SignedHeaders="+signedHeaders+", Signature="+signature)
	resp, err := (&http.Client{Timeout: 30 * time.Second}).Do(u)
	if err != nil {
		return nil, fmt.Errorf("请求华为云 API 失败: %w", err)
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("读取华为云响应失败: %w", err)
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil, fmt.Errorf("华为云 API 返回 HTTP %d: %s", resp.StatusCode, string(body))
	}
	return body, nil
}

// ListRegions 获取当前账号的项目列表，项目 ID 作为可用于 ECS 请求的区域代码。 // Logan.Li
func (p *HuaweiProvider) ListRegions() ([]CloudRegion, error) {
	body, err := p.signedGet("https://iam.myhuaweicloud.com/v3/projects", "iam")
	if err != nil {
		return nil, err
	}
	var result struct {
		Projects []struct {
			ID   string `json:"id"`
			Name string `json:"name"`
		} `json:"projects"`
	}
	if err := json.Unmarshal(body, &result); err != nil {
		return nil, fmt.Errorf("解析华为云区域响应失败: %w", err)
	}
	regions := []CloudRegion{}
	regionByProject := make(map[string]string, len(result.Projects))
	for _, project := range result.Projects {
		if project.ID == "" || project.Name == "" {
			continue
		}
		regions = append(regions, CloudRegion{RegionID: project.ID, LocalName: project.Name, Endpoint: "https://ecs." + project.Name + ".myhuaweicloud.com", Status: "active"})
		regionByProject[project.ID] = project.Name
	}
	p.regionMu.Lock()
	p.regionByProject = regionByProject
	p.regionMu.Unlock()
	sort.Slice(regions, func(i, j int) bool { return regions[i].LocalName < regions[j].LocalName })
	return regions, nil
}

// ListInstances 获取指定华为云项目中的 ECS 实例。 // Logan.Li
func (p *HuaweiProvider) ListInstances(projectID string) ([]CloudInstance, error) {
	p.regionMu.RLock()
	regionName := p.regionByProject[projectID]
	p.regionMu.RUnlock()
	if regionName == "" {
		if _, err := p.ListRegions(); err != nil {
			return nil, err
		}
		p.regionMu.RLock()
		regionName = p.regionByProject[projectID]
		p.regionMu.RUnlock()
	}
	if regionName == "" {
		return nil, fmt.Errorf("未找到华为云项目 %s", projectID)
	}
	body, err := p.signedGet("https://ecs."+regionName+".myhuaweicloud.com/v2.1/"+projectID+"/servers/detail", "ecs")
	if err != nil {
		return nil, err
	}
	var result struct {
		Servers []struct {
			ID     string `json:"id"`
			Name   string `json:"name"`
			Status string `json:"status"`
			Flavor struct {
				ID string `json:"id"`
			} `json:"flavor"`
			Created   string            `json:"created"`
			Metadata  map[string]string `json:"metadata"`
			Addresses map[string][]struct {
				Addr string `json:"addr"`
				Type string `json:"OS-EXT-IPS:type"`
			} `json:"addresses"`
			Zone string `json:"OS-EXT-AZ:availability_zone"`
		} `json:"servers"`
	}
	if err := json.Unmarshal(body, &result); err != nil {
		return nil, fmt.Errorf("解析华为云实例响应失败: %w", err)
	}
	instances := []CloudInstance{}
	for _, server := range result.Servers {
		privateIP, publicIP := "", ""
		for _, addresses := range server.Addresses {
			for _, address := range addresses {
				if address.Type == "floating" {
					publicIP = address.Addr
				} else if privateIP == "" {
					privateIP = address.Addr
				}
			}
		}
		osType := server.Metadata["os_type"]
		if osType == "" {
			osType = server.Metadata["__os_type"]
		}
		instances = append(instances, CloudInstance{InstanceID: server.ID, InstanceName: server.Name, Hostname: server.Name, OSType: osType, Status: huaweiState(server.Status), RegionID: projectID, ZoneID: server.Zone, PrivateIP: privateIP, PublicIP: publicIP, InstanceType: server.Flavor.ID, CreationTime: server.Created})
	}
	return instances, nil
}

// huaweiState 统一华为云实例状态，便于复用导入逻辑。 // Logan.Li
func huaweiState(state string) string {
	if strings.EqualFold(state, "ACTIVE") {
		return "Running"
	}
	return state
}