# data-flow

# DATA FLOW

sequenceDiagram participant Citizen as 👤 Citizen participant Frontend as 🌐 Frontend
Next.js participant API as 📡 NestJS API participant DB as 🗄️ PostgreSQL participant MinIO as 📦 MinIO participant Blockchain as ⛓️ Besu
Smart Contracts participant Dept1 as 🏢 Dept 1
Approver participant Dept2 as 🏢 Dept 2
Approver participant Webhook as 🔔 Webhook rect rgb(31, 41, 55) note over Citizen,API: 1. License Request Submission Citizen->>Frontend: Create Resort License
Request & Upload
Documents Frontend->>API: POST /licenses/create
Form Data + Files API->>DB: Create license_request
status: DRAFT end rect rgb(59, 130, 246) note over API,MinIO: 2. Document Upload & Hashing API->>MinIO: Upload Documents
(PDF, Images, etc.) MinIO-->>API: Document URLs API->>API: Generate SHA-256
Hash of Files API->>DB: Store document_metadata
with content_hash end rect rgb(168, 85, 247) note over API,Blockchain: 3. Blockchain Recording API->>Blockchain: Call DocumentRegistrar
recordDocumentHash()
params: licenseHash,
department, timestamp Blockchain->>Blockchain: Emit DocumentHashRecorded
event Blockchain->>DB: Store blockchain
tx_hash in license_request API-->>Frontend: Request Submitted Frontend-->>Citizen: Confirmation + Request ID end rect rgb(20, 184, 166) note over DB,DB: 4. Update to SUBMITTED State API->>DB: Update license_request
status: SUBMITTED API->>DB: Create audit_log entry end rect rgb(59, 130, 246) note over API,Dept1: 5. Route to Department 1 API->>API: Resolve workflow for
Resort License POC API->>DB: Create approval_request
status: PENDING
department: Tourism API->>Webhook: Send notification Webhook->>Dept1: Email: License
Ready for Review end rect rgb(139, 92, 246) note over API,Dept2: 6. Route to Department 2 (Parallel) par Department 2 Review API->>DB: Create approval_request
status: PENDING
department: Fire Safety API->>Webhook: Send notification Webhook->>Dept2: Email: License
Ready for Review end end rect rgb(34, 197, 94) note over Dept1,Blockchain: 7. Department 1 Approval Dept1->>Frontend: Review Documents
& Attachments Dept1->>API: POST /approvals/approve
approval_id, comments API->>DB: Update approval_request
status: APPROVED
reviewed_by, timestamp API->>Blockchain: Call ApprovalManager
recordApproval()
params: licenseHash,
department, signature Blockchain->>Blockchain: Emit ApprovalRecorded end rect rgb(34, 197, 94) note over Dept2,Blockchain: 8. Department 2 Approval (Parallel) par Department 2 Review Dept2->>Frontend: Review Documents Dept2->>API: POST /approvals/approve API->>DB: Update approval_request
status: APPROVED API->>Blockchain: recordApproval() Blockchain->>Blockchain: Emit ApprovalRecorded end end rect rgb(236, 72, 153) note over API,Blockchain: 9. Final Approval Processing API->>API: Check all approvals
complete API->>Blockchain: Call LicenseRequestNFT
mint()
params: applicant,
licenseURI, metadata Blockchain->>Blockchain: Mint ERC-721
Soulbound NFT Blockchain->>Blockchain: Emit Transfer event end rect rgb(20, 184, 166) note over DB,Frontend: 10. Update Final State API->>DB: Update license_request
status: APPROVED
nft_token_id API->>DB: Create audit_log
entry: APPROVED API->>Webhook: Send notification Webhook->>Citizen: Email: License
Approved! API-->>Frontend: License Approved Frontend-->>Citizen: Display NFT &
Certificate end rect rgb(96, 125, 139) note over Citizen,Frontend: 11. License Verification Citizen->>Frontend: Download License
Certificate Frontend->>API: GET /licenses/{id}
/verify API->>Blockchain: query getLicenseNFT()
tokenId Blockchain-->>API: NFT metadata,
owner, issuer API-->>Frontend: Verified ✓ Frontend-->>Citizen: Display Verified
License Certificate end