13 — File Storage Architecture

flowchart TB
    Storage["File Storage Types"] --> Object["Object Storage<br/>S3, GCS, Azure Blob<br/>Unlimited scale<br/>HTTP API access"]
    Storage --> Block["Block Storage<br/>EBS, SSD, HDD<br/>Fast, low-latency<br/>Attached to servers"]
    Storage --> File["File Storage<br/>EFS, NFS, NAS<br/>Shared access<br/>POSIX compatible"]

    Object --> ObjectUse["Use: Images, videos, backups, static assets"]
    Block --> BlockUse["Use: Database storage, OS volumes, temp files"]
    File --> FileUse["Use: Shared configs, home directories, logs"]

    style Storage fill:#7c3aed,color:#fff
    style Object fill:#3b82f6,color:#fff
    style Block fill:#f59e0b,color:#fff
    style File fill:#059669,color:#fff

flowchart TB
    subgraph S3["Amazon S3 (Object Storage)"]
        Bucket["📦 Bucket<br/>Globally unique name"]
        Objects["📄 Objects (files)<br/>Key: path/to/file.jpg<br/>Value: binary data<br/>Metadata: content-type, size"]
        Bucket --> Objects
    end

    subgraph Access["Access Patterns"]
        HTTP["HTTP REST API<br/>PUT / GET / DELETE"]
        SDK["AWS SDK / CLI<br/>s3 cp, s3 sync"]
        CDN["CloudFront CDN<br/>Global distribution"]
    end

    Objects --> HTTP & SDK & CDN

    subgraph Security["Security"]
        BP["Bucket Policies"]
        IAM["IAM Permissions"]
        Enc["Encryption (SSE)"]
    end

    style S3 fill:#7c3aed,color:#fff
    style Access fill:#3b82f6,color:#fff
    style Security fill:#059669,color:#fff

sequenceDiagram
    participant User as User Browser
    participant App as Application
    participant S3 as S3 / Object Store
    participant CDN as CDN
    participant Worker as Processing Worker

    User->>App: Request upload URL
    App->>App: Generate presigned URL
    App-->>User: Presigned PUT URL (expires in 15 min)

    User->>S3: PUT directly to S3 (via presigned URL)
    S3-->>User: Upload complete ✅

    Note over S3: S3 event notification triggers

    S3->>Worker: File uploaded event
    Worker->>S3: Download file
    Worker->>Worker: Process (resize, compress, thumbnail)
    Worker->>S3: Save processed versions

    User->>App: Request file
    App-->>User: CDN URL

    User->>CDN: GET /images/photo.jpg
    CDN-->>User: Cached file (or fetch from S3)

flowchart LR
    Upload["📤 Upload"] --> Hot["Hot Storage<br/>S3 Standard<br/>💰 $$$<br/>Instant access"]
    Hot -->|"30-90 days"| Warm["Warm Storage<br/>S3 Standard-IA<br/>💰 $$<br/>Instant access"]
    Warm -->|"90-365 days"| Cold["Cold Storage<br/>S3 Glacier<br/>💰 $<br/>Min. retrieval"]
    Cold -->|"> 365 days"| Archive["Archive<br/>Glacier Deep Archive<br/>💰 ¢<br/>12hr retrieval"]

    style Hot fill:#3b82f6,color:#fff
    style Warm fill:#059669,color:#fff
    style Cold fill:#f59e0b,color:#fff
    style Archive fill:#ef4444,color:#fff

flowchart TB
    subgraph Upload["Upload Path"]
        User["User Device"] -->|Upload| UploadAPI["Upload API"]
        UploadAPI -->|Store| S3["S3 Bucket<br/>Original files"]
    end

    subgraph Process["Processing Path"]
        S3 -->|Event| Worker["Processing Worker<br/>Resize, compress, thumbnail"]
        Worker -->|Store| Processed["S3 Bucket<br/>Processed files"]
    end

    subgraph Serve["Serving Path"]
        Processed --> CDN["CloudFront CDN<br/>Edge caching"]
        CDN -->|Serve| User
    end

    style Upload fill:#3b82f6,color:#fff
    style Process fill:#7c3aed,color:#fff
    style Serve fill:#059669,color:#fff