package controller

import (
	"errors"
	"fmt"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/heicode/manager/common"
	"github.com/heicode/manager/model"
	"gorm.io/gorm"
)

// Cloud resource discovery — provider-agnostic layer (#5).
//
// 历史上只有 Azure 发现（controller/azure_resource_discovery.go，硬要求 provider==azure）。
// 本文件抽象出统一的 provider 接口，让 AWS / GCP 走同一条「发现 → 归一化 → 落库」路径，
// 并对 vm / database / blob 做跨云一致的分类（DoD #3）。Azure 适配器复用既有 ARM 客户端，
// 故三家行为一致；具体云的签名/鉴权在 aws_resource_discovery.go / gcp_resource_discovery.go。

// discoveredCloudResource 是各 provider 适配器输出的**归一化**资源视图。upsert 时由统一
// 路径补 source_account_id 与 classified_type，并写入 ResourceBinding(resource_type=cloud_resource)。
type discoveredCloudResource struct {
	ExternalId   string         // ARN / Azure resource id / GCP asset name —— 跨 provider 的稳定外部 id
	Name         string         // 展示名
	NativeType   string         // provider 原生类型字符串（如 Microsoft.Compute/virtualMachines、AWS::EC2::Instance、compute.googleapis.com/Instance）
	Location     string         // region / location
	BindingScope string         // 可选；为空时默认 "<provider>:<external_id>"
	Metadata     map[string]any // provider 特定附加字段
}

// cloudDiscoveryProvider 是「连接云账号 → 列资源」的统一抽象（DoD #3）。
type cloudDiscoveryProvider interface {
	name() string
	// discover 用 creds（已合并 metadata + secret JSON）列出 account 下的资源。
	discover(account model.ResourceBinding, creds map[string]any) ([]discoveredCloudResource, error)
}

func cloudDiscoveryProviderByName(provider string) (cloudDiscoveryProvider, bool) {
	switch strings.ToLower(strings.TrimSpace(provider)) {
	case "azure":
		return azureCloudDiscoveryProvider{}, true
	case "aws", "amazon":
		return awsCloudDiscoveryProvider{}, true
	case "gcp", "google", "gce":
		return gcpCloudDiscoveryProvider{}, true
	}
	return nil, false
}

// classifyCloudResourceType 把 provider 原生类型映射到跨云一致的逻辑类别（DoD #3）：
// vm / database / blob / cloud_resource(兜底)。基于不区分大小写的子串匹配，覆盖三家常见服务。
func classifyCloudResourceType(nativeType string) string {
	t := strings.ToLower(nativeType)
	containsAny := func(s string, subs ...string) bool {
		for _, sub := range subs {
			if strings.Contains(s, sub) {
				return true
			}
		}
		return false
	}
	switch {
	// 数据库（放在 vm 之前：避免 "sqlvirtual..." 之类被误判为 vm；数据库特征更强）
	case containsAny(t, "sql", "postgres", "mysql", "mariadb", "rds", "database", "cosmos",
		"dynamodb", "spanner", "cloudsql", "bigtable", "redis", "documentdb", "memcache"):
		return "database"
	case containsAny(t, "virtualmachine", "ec2::instance", "ec2/instance", "compute/instance",
		"compute.googleapis.com/instance", "virtualmachinescaleset", "instance"):
		return "vm"
	case containsAny(t, "storageaccount", "::s3::", "s3:::", "/buckets/", "storage/bucket",
		"storage.googleapis.com/bucket", "blob", "bucket"):
		return "blob"
	default:
		return "cloud_resource"
	}
}

// upsertDiscoveredCloudResources 把归一化资源幂等写入 ResourceBinding（按 user+type+provider+external_id
// 去重）。统一所有 provider 的落库格式：resource_type 固定为 cloud_resource（与既有 Azure 行为一致，
// 不让发现的资源直接变成可绑定的 vm/db/blob），跨云类别放在 metadata.classified_type。
func upsertDiscoveredCloudResources(account model.ResourceBinding, provider string, discovered []discoveredCloudResource) ([]resourceResponse, error) {
	items := make([]resourceResponse, 0, len(discovered))
	for _, d := range discovered {
		if strings.TrimSpace(d.ExternalId) == "" {
			continue
		}
		var resource model.ResourceBinding
		err := model.DB.Where(
			"user_id = ? AND resource_type = ? AND provider = ? AND external_id = ?",
			account.UserId, "cloud_resource", provider, d.ExternalId,
		).First(&resource).Error
		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, err
		}
		if err := applyDiscoveredResourceFields(&resource, account, provider, d); err != nil {
			return nil, err
		}
		if resource.Id == 0 {
			if err := model.DB.Create(&resource).Error; err != nil {
				return nil, err
			}
		} else if err := model.DB.Save(&resource).Error; err != nil {
			return nil, err
		}
		items = append(items, resourceToResponse(resource))
	}
	return items, nil
}

// applyDiscoveredResourceFields 把一条归一化发现结果写入 ResourceBinding 字段(DB 无关,可单测)。
// 关键安全约束(#5 复审 #1):**SecretRef 恒为空**——发现出的子资源绝不继承云账号 secret_ref,
// 否则会把账号级凭据引用扩散到每个 VM/S3/DB 并经 resourceToResponse / grant manifest 下发给 agent。
// 发现是只读清单;如需 agent 读取某资源,应另行 grant/审批/最小权限 secret。
func applyDiscoveredResourceFields(resource *model.ResourceBinding, account model.ResourceBinding, provider string, d discoveredCloudResource) error {
	metadata := map[string]any{}
	for k, v := range d.Metadata {
		metadata[k] = v
	}
	metadata["source_account_id"] = account.Id
	metadata["classified_type"] = classifyCloudResourceType(d.NativeType)
	if strings.TrimSpace(d.NativeType) != "" {
		metadata["native_type"] = d.NativeType
	}
	if strings.TrimSpace(d.Location) != "" {
		metadata["location"] = d.Location
	}
	metadataJSON, err := marshalResourceJSON(metadata)
	if err != nil {
		return err
	}
	permissionScopeJSON, err := marshalResourceJSON(map[string]any{"actions": []string{provider + ":read"}})
	if err != nil {
		return err
	}
	constraintsJSON, err := marshalResourceJSON(unmarshalResourceJSON(account.Constraints))
	if err != nil {
		return err
	}
	name := strings.TrimSpace(d.Name)
	if name == "" {
		name = d.ExternalId
	}
	bindingScope := strings.TrimSpace(d.BindingScope)
	if bindingScope == "" {
		bindingScope = fmt.Sprintf("%s:%s", provider, d.ExternalId)
	}
	resource.UserId = account.UserId
	resource.TenantId = account.TenantId
	resource.ProjectId = account.ProjectId
	resource.BindingScope = bindingScope
	resource.Name = name
	resource.ResourceType = "cloud_resource"
	resource.Provider = provider
	resource.ExternalId = d.ExternalId
	resource.SecretRef = "" // 见上:绝不继承账号 secret_ref
	resource.Metadata = metadataJSON
	resource.PermissionScope = permissionScopeJSON
	resource.Constraints = constraintsJSON
	resource.Status = "active"
	return nil
}

// DiscoverCloudResources: POST /api/resources/:id/discover-cloud — provider-agnostic
// discovery dispatcher (#5). Routes by the account's provider to the matching
// adapter (azure/aws/gcp), then upserts via the unified path.
func DiscoverCloudResources(c *gin.Context) {
	userId := c.GetInt("id")
	var account model.ResourceBinding
	if err := model.DB.Where("id = ? AND user_id = ?", c.Param("id"), userId).First(&account).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			common.ApiErrorMsg(c, "resource not found")
			return
		}
		common.ApiError(c, err)
		return
	}
	if account.ResourceType != "cloud_account" || account.Status != "active" {
		common.ApiErrorMsg(c, "resource must be an active cloud_account")
		return
	}
	impl, ok := cloudDiscoveryProviderByName(account.Provider)
	if !ok {
		common.ApiErrorMsg(c, "unsupported cloud provider: "+account.Provider+" (supported: azure, aws, gcp)")
		return
	}

	// creds = metadata（非密）合并 secret JSON（密）。secret 优先级在适配器内部按需处理。
	creds := unmarshalResourceJSON(account.Metadata)
	if creds == nil {
		creds = map[string]any{}
	}
	if strings.TrimSpace(account.SecretRef) != "" {
		secretClient, err := newSecretStoreClientFromEnv()
		if err != nil {
			common.ApiError(c, err)
			return
		}
		secretData, err := secretClient.getJSONSecret(account.SecretRef)
		if err != nil {
			common.ApiError(c, err)
			return
		}
		for k, v := range secretData {
			creds[k] = v // secret 覆盖同名非密字段
		}
	}

	discovered, err := impl.discover(account, creds)
	if err != nil {
		common.ApiError(c, err)
		return
	}
	items, err := upsertDiscoveredCloudResources(account, impl.name(), discovered)
	if err != nil {
		common.ApiError(c, err)
		return
	}
	common.ApiSuccess(c, gin.H{
		"account":    resourceToResponse(account),
		"provider":   impl.name(),
		"items":      items,
		"discovered": len(items),
	})
}

// azureCloudDiscoveryProvider 让既有 Azure ARM 发现实现统一接口（复用 azure_resource_discovery.go
// 的 client/token/list），保证三家走同一抽象。
type azureCloudDiscoveryProvider struct{}

func (azureCloudDiscoveryProvider) name() string { return "azure" }

func (azureCloudDiscoveryProvider) discover(account model.ResourceBinding, creds map[string]any) ([]discoveredCloudResource, error) {
	cred := azureDiscoveryCredentials{
		SubscriptionID: firstString(creds, nil, account.ExternalId, "subscription_id"),
		TenantID:       firstString(creds, nil, account.TenantId, "tenant_id"),
		ClientID:       mapString(creds, "client_id"),
		ClientSecret:   mapString(creds, "client_secret"),
	}
	if err := cred.validate(); err != nil {
		return nil, err
	}
	client := newAzureResourceDiscoveryClientFromEnv()
	token, err := client.clientCredentialsToken(cred)
	if err != nil {
		return nil, err
	}
	arm, err := client.listSubscriptionResources(cred.SubscriptionID, token)
	if err != nil {
		return nil, err
	}
	out := make([]discoveredCloudResource, 0, len(arm))
	for _, r := range arm {
		out = append(out, discoveredCloudResource{
			ExternalId:   r.ID,
			Name:         r.Name,
			NativeType:   r.Type,
			Location:     r.Location,
			BindingScope: fmt.Sprintf("azure:%s:%s", cred.SubscriptionID, r.ID),
			Metadata: map[string]any{
				"subscription_id": cred.SubscriptionID,
				"tenant_id":       cred.TenantID,
				"resource_group":  azureResourceGroupFromID(r.ID),
				"tags":            r.Tags,
			},
		})
	}
	return out, nil
}