src/api/main.py

"""FastAPI application for DocFlow AI."""

from __future__ import annotations

import io
import os
import sys
import tempfile
from pathlib import Path

from fastapi import Depends, FastAPI, File, HTTPException, Query, UploadFile
from fastapi.responses import StreamingResponse
from sqlalchemy.orm import Session

ROOT = Path(__file__).resolve().parents[1]
sys.path.insert(0, str(ROOT))

from api.database import get_db, init_db  # noqa: E402
from api.review_service import approve_review, create_review, get_review, list_reviews, reject_review  # noqa: E402
from api.schemas import ExtractResponse, HealthResponse, ReviewAction, ReviewDetail, ReviewSummary  # noqa: E402
from docflow.export import to_excel_bytes, to_json  # noqa: E402
from docflow.pipeline import DocFlowPipeline  # noqa: E402

app = FastAPI(
    title="DocFlow AI API",
    description="Enterprise invoice extraction and accountant review workflow by Aria AI",
    version="1.0.0",
    docs_url="/docs",
    redoc_url="/redoc",
)

pipeline = DocFlowPipeline(validate=True)
MAX_UPLOAD_MB = int(os.getenv("MAX_UPLOAD_SIZE_MB", "10"))
ALLOWED_TYPES = {"image/png", "image/jpeg", "image/jpg", "application/pdf"}


@app.on_event("startup")
def on_startup() -> None:
    init_db()


@app.get("/health", response_model=HealthResponse)
def health(db: Session = Depends(get_db)) -> HealthResponse:
    try:
        db.execute(__import__("sqlalchemy").text("SELECT 1"))
        db_status = "connected"
    except Exception:
        db_status = "disconnected"
    return HealthResponse(database=db_status)


@app.post("/v1/invoices/extract", response_model=ExtractResponse)
async def extract_invoice(
    file: UploadFile = File(...),
    validate: bool = Query(True),
    queue_review: bool = Query(True),
    db: Session = Depends(get_db),
) -> ExtractResponse:
    if file.content_type not in ALLOWED_TYPES:
        raise HTTPException(400, f"Unsupported file type: {file.content_type}")

    content = await file.read()
    if len(content) > MAX_UPLOAD_MB * 1024 * 1024:
        raise HTTPException(413, f"File exceeds {MAX_UPLOAD_MB}MB limit")

    suffix = Path(file.filename or "upload.png").suffix or ".png"
    with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as tmp:
        tmp.write(content)
        tmp_path = tmp.name

    try:
        pipeline.validate = validate
        invoice, validation, _ = pipeline.process(tmp_path)
    except Exception as exc:
        raise HTTPException(422, f"OCR/processing failed: {exc}") from exc
    finally:
        Path(tmp_path).unlink(missing_ok=True)

    review_id = None
    if queue_review:
        review = create_review(db, invoice, validation)
        review_id = review.id

    return ExtractResponse(
        invoice=invoice.to_export_dict(),
        validation=validation.model_dump() if validation else None,
        review_id=review_id,
    )


@app.post("/v1/invoices/export/excel")
async def export_excel(
    file: UploadFile = File(...),
    validate: bool = Query(True),
):
    content = await file.read()
    suffix = Path(file.filename or "upload.png").suffix or ".png"
    with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as tmp:
        tmp.write(content)
        tmp_path = tmp.name

    try:
        pipeline.validate = validate
        invoice, validation, _ = pipeline.process(tmp_path)
        excel_bytes = to_excel_bytes(invoice, validation)
    except Exception as exc:
        raise HTTPException(422, f"Processing failed: {exc}") from exc
    finally:
        Path(tmp_path).unlink(missing_ok=True)

    return StreamingResponse(
        io.BytesIO(excel_bytes),
        media_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        headers={"Content-Disposition": "attachment; filename=docflow_export.xlsx"},
    )


@app.get("/v1/reviews", response_model=list[ReviewSummary])
def get_reviews(status: str | None = Query(None), db: Session = Depends(get_db)) -> list[ReviewSummary]:
    reviews = list_reviews(db, status=status)
    return [
        ReviewSummary(
            id=r.id,
            vendor_name=r.vendor_name,
            invoice_number=r.invoice_number,
            total_amount=r.total_amount,
            currency=r.currency,
            confidence=r.confidence,
            status=r.status,
            created_at=r.created_at,
            reviewer=r.reviewer,
        )
        for r in reviews
    ]


@app.get("/v1/reviews/{review_id}", response_model=ReviewDetail)
def get_review_detail(review_id: str, db: Session = Depends(get_db)) -> ReviewDetail:
    review = get_review(db, review_id)
    if not review:
        raise HTTPException(404, "Review not found")
    return ReviewDetail(
        id=review.id,
        vendor_name=review.vendor_name,
        invoice_number=review.invoice_number,
        total_amount=review.total_amount,
        currency=review.currency,
        confidence=review.confidence,
        status=review.status,
        created_at=review.created_at,
        reviewer=review.reviewer,
        invoice_data=review.invoice_data,
        validation_data=review.validation_data,
        review_notes=review.review_notes,
        reviewed_at=review.reviewed_at,
    )


@app.post("/v1/reviews/{review_id}/approve", response_model=ReviewDetail)
def approve(review_id: str, action: ReviewAction, db: Session = Depends(get_db)) -> ReviewDetail:
    review = approve_review(db, review_id, action.reviewer, action.notes)
    if not review:
        raise HTTPException(404, "Review not found")
    return get_review_detail(review_id, db)


@app.post("/v1/reviews/{review_id}/reject", response_model=ReviewDetail)
def reject(review_id: str, action: ReviewAction, db: Session = Depends(get_db)) -> ReviewDetail:
    review = reject_review(db, review_id, action.reviewer, action.notes)
    if not review:
        raise HTTPException(404, "Review not found")
    return get_review_detail(review_id, db)