Process invoices from Gmail into Google Sheets with Slack approval

flowchart TD trig>"new invoice email arrives"]:::trig s0["read PDF attachment text"]:::task s1["AI extracts invoice details"]:::task s2[("log invoice to sheet")]:::store s3["send Slack approval request"]:::svc trig --> s0 s0 --> s1 s1 --> s2 s2 --> s3 gx{"× approve or reject invoice"}:::gate s3 --> gx p00["mark approved in sheet"]:::task gx -->|"Approve"| p00 p10["mark rejected in sheet"]:::task gx -->|"Reject"| p10 jn{"○ update sheet status"}:::gate p00 --> jn p10 --> jn jn --> out out[/"invoice logged with approval status"/]:::out pay{{"faster processing with clear audit trail"}}:::pay out --> pay classDef task fill:#e7f6fe,stroke:#34b8f0,color:#2c2a29 classDef svc fill:#f6f8fa,stroke:#7c8795,color:#2c2a29 classDef mi fill:#e7f6fe,stroke:#0079a8,color:#2c2a29,stroke-width:2px classDef human fill:#fff,stroke:#0079a8,color:#0079a8 classDef store fill:#f6f8fa,stroke:#0079a8,color:#2c2a29 classDef trig fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigtime fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigdata fill:#8ad4f5,stroke:#0079a8,color:#06314c,font-weight:bold classDef gate fill:#fff,stroke:#e8a23d,color:#6b4708,font-weight:bold classDef out fill:#1f9d6b,stroke:#167a53,color:#fff,font-weight:bold classDef pay fill:#06314c,stroke:#021f33,color:#fff