package cloud

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"
)

// AzureProvider 使用服务主体凭据同步 Azure Resource Manager 虚拟机。 // Logan.Li
type AzureProvider struct{ tenantID, subscriptionID, clientID, clientSecret string }

// NewAzureProvider 创建 Azure Provider，AccessKey 格式为 tenantId:subscriptionId:clientId。 // Logan.Li
func NewAzureProvider(accessKey, secretKey string) *AzureProvider {
	parts := strings.Split(accessKey, ":")
	p := &AzureProvider{clientSecret: secretKey}
	if len(parts) == 3 {
		p.tenantID, p.subscriptionID, p.clientID = parts[0], parts[1], parts[2]
	}
	return p
}

// Name 返回 Azure 厂商标识。 // Logan.Li
func (p *AzureProvider) Name() string { return "azure" }

// token 获取 ARM 所需的服务主体访问令牌。 // Logan.Li
func (p *AzureProvider) token() (string, error) {
	if p.tenantID == "" || p.subscriptionID == "" || p.clientID == "" || p.clientSecret == "" {
		return "", fmt.Errorf("Azure AccessKey 应为 租户ID:订阅ID:客户端ID，SecretKey 应为客户端密钥")
	}
	form := url.Values{"client_id": {p.clientID}, "client_secret": {p.clientSecret}, "grant_type": {"client_credentials"}, "scope": {"https://management.azure.com/.default"}}
	resp, err := (&http.Client{Timeout: 30 * time.Second}).PostForm("https://login.microsoftonline.com/"+p.tenantID+"/oauth2/v2.0/token", form)
	if err != nil {
		return "", fmt.Errorf("获取 Azure 令牌失败: %w", err)
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return "", fmt.Errorf("Azure 令牌接口返回 HTTP %d: %s", resp.StatusCode, string(body))
	}
	var data struct {
		Token string `json:"access_token"`
	}
	if err := json.Unmarshal(body, &data); err != nil || data.Token == "" {
		return "", fmt.Errorf("解析 Azure 令牌失败")
	}
	return data.Token, nil
}

// get 调用 Azure Resource Manager GET API。 // Logan.Li
func (p *AzureProvider) get(path string) ([]byte, error) {
	token, err := p.token()
	if err != nil {
		return nil, err
	}
	req, err := http.NewRequest(http.MethodGet, "https://management.azure.com"+path, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Authorization", "Bearer "+token)
	resp, err := (&http.Client{Timeout: 30 * time.Second}).Do(req)
	if err != nil {
		return nil, fmt.Errorf("请求 Azure API 失败: %w", err)
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil, fmt.Errorf("Azure API 返回 HTTP %d: %s", resp.StatusCode, string(body))
	}
	return body, nil
}

// ListRegions 获取 Azure 订阅可用区域。 // Logan.Li
func (p *AzureProvider) ListRegions() ([]CloudRegion, error) {
	body, err := p.get("/subscriptions/" + p.subscriptionID + "/locations?api-version=2022-12-01")
	if err != nil {
		return nil, err
	}
	var result struct {
		Value []struct {
			Name        string `json:"name"`
			DisplayName string `json:"displayName"`
		} `json:"value"`
	}
	if err := json.Unmarshal(body, &result); err != nil {
		return nil, fmt.Errorf("解析 Azure 区域响应失败: %w", err)
	}
	regions := []CloudRegion{}
	for _, item := range result.Value {
		regions = append(regions, CloudRegion{RegionID: item.Name, LocalName: item.DisplayName, Endpoint: "https://management.azure.com", Status: "active"})
	}
	return regions, nil
}

// ListInstances 获取 Azure 指定区域的虚拟机并保留 ARM 提供的基础元数据。 // Logan.Li
func (p *AzureProvider) ListInstances(regionID string) ([]CloudInstance, error) {
	body, err := p.get("/subscriptions/" + p.subscriptionID + "/providers/Microsoft.Compute/virtualMachines?api-version=2024-03-01")
	if err != nil {
		return nil, err
	}
	var result struct {
		Value []struct {
			ID         string `json:"id"`
			Name       string `json:"name"`
			Location   string `json:"location"`
			Properties struct {
				Hardware struct {
					VMSize string `json:"vmSize"`
				} `json:"hardwareProfile"`
				OS struct {
					Type string `json:"osType"`
					Name string `json:"computerName"`
				} `json:"osProfile"`
				Provisioning string `json:"provisioningState"`
			} `json:"properties"`
		} `json:"value"`
	}
	if err := json.Unmarshal(body, &result); err != nil {
		return nil, fmt.Errorf("解析 Azure 实例响应失败: %w", err)
	}
	instances := []CloudInstance{}
	for _, item := range result.Value {
		if !strings.EqualFold(item.Location, regionID) {
			continue
		}
		instances = append(instances, CloudInstance{InstanceID: item.ID, InstanceName: item.Name, Hostname: item.Properties.OS.Name, OSType: item.Properties.OS.Type, Status: azureState(item.Properties.Provisioning), RegionID: item.Location, InstanceType: item.Properties.Hardware.VMSize})
	}
	return instances, nil
}

// azureState 统一 Azure 实例状态，便于复用导入逻辑。 // Logan.Li
func azureState(state string) string {
	if strings.EqualFold(state, "Succeeded") {
		return "Running"
	}
	return state
}