from __future__ import annotations

from collections.abc import Generator
from datetime import UTC, date, datetime
from decimal import Decimal

from fastapi.testclient import TestClient
from sqlalchemy import create_engine
from sqlalchemy.orm import Session, sessionmaker
from sqlalchemy.pool import StaticPool

from app.api.deps import get_db
from app.db.base import Base
from app.main import create_app
from app.models.employee import Employee
from app.models.financial_record import ExpenseClaim, ExpenseClaimItem
from app.models.role import Role
from app.schemas.ocr import OcrRecognizeBatchRead, OcrRecognizeDocumentRead
from app.services.expense_claims import ExpenseClaimService
from app.services.ocr import OcrService


def build_session_factory() -> sessionmaker[Session]:
    engine = create_engine(
        "sqlite+pysqlite:///:memory:",
        connect_args={"check_same_thread": False},
        poolclass=StaticPool,
    )
    Base.metadata.create_all(bind=engine)
    return sessionmaker(bind=engine, autoflush=False, autocommit=False)


def build_client() -> tuple[TestClient, sessionmaker[Session]]:
    session_factory = build_session_factory()
    app = create_app()

    def override_db() -> Generator[Session, None, None]:
        db = session_factory()
        try:
            yield db
        finally:
            db.close()

    app.dependency_overrides[get_db] = override_db
    return TestClient(app), session_factory


def seed_claim(db: Session) -> tuple[ExpenseClaim, ExpenseClaimItem]:
    manager = Employee(
        id="mgr-1",
        employee_no="E20001",
        name="李总",
        email="manager@example.com",
        position="市场总监",
        grade="P7",
    )
    role = Role(
        id="role-user",
        role_code="user",
        name="员工",
        description="普通员工",
    )
    employee = Employee(
        id="emp-1",
        employee_no="E10001",
        name="张三",
        email="zhangsan@example.com",
        position="招商主管",
        grade="P4",
        manager=manager,
        roles=[role],
    )
    claim = ExpenseClaim(
        id="claim-attachment-1",
        claim_no="EXP-202605-101",
        employee_id=employee.id,
        employee_name="张三",
        department_id="dept-1",
        department_name="市场部",
        project_code=None,
        expense_type="office",
        reason="办公用品采购",
        location="深圳南山",
        amount=Decimal("88.00"),
        currency="CNY",
        invoice_count=0,
        occurred_at=datetime(2026, 5, 13, tzinfo=UTC),
        submitted_at=None,
        status="draft",
        approval_stage="待提交",
        risk_flags_json=[],
    )
    item = ExpenseClaimItem(
        id="item-attachment-1",
        claim_id=claim.id,
        item_date=date(2026, 5, 13),
        item_type="office",
        item_reason="办公用品采购",
        item_location="深圳南山",
        item_amount=Decimal("88.00"),
        invoice_id=None,
    )
    claim.items = [item]
    db.add(manager)
    db.add(role)
    db.add(employee)
    db.add(claim)
    db.commit()
    return claim, item


def test_claim_item_attachment_upload_preview_and_delete(monkeypatch, tmp_path) -> None:
    def fake_recognize(
        self,
        files: list[tuple[str, bytes, str | None]],
    ) -> OcrRecognizeBatchRead:
        assert files[0][0] == "office-note.png"
        return OcrRecognizeBatchRead(
            total_file_count=1,
            success_count=1,
            documents=[
                OcrRecognizeDocumentRead(
                    filename="office-note.png",
                    media_type="image/png",
                    text="办公用品发票 金额88元 2026-05-13",
                    summary="识别到办公用品发票，金额 88 元。",
                    avg_score=0.98,
                    line_count=1,
                    page_count=1,
                    warnings=[],
                )
            ],
        )

    monkeypatch.setattr(OcrService, "recognize_files", fake_recognize)
    monkeypatch.setattr(ExpenseClaimService, "_get_attachment_storage_root", lambda self: tmp_path)

    client, session_factory = build_client()
    with session_factory() as db:
        claim, item = seed_claim(db)
        claim_id = claim.id
        item_id = item.id

    headers = {"x-auth-username": "emp-1", "x-auth-name": "Zhang San"}
    file_bytes = b"fake-image-bytes"

    upload_response = client.post(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment",
        headers=headers,
        files=[("file", ("office-note.png", file_bytes, "image/png"))],
    )

    assert upload_response.status_code == 200
    upload_payload = upload_response.json()
    assert upload_payload["attachment"]["file_name"] == "office-note.png"
    assert upload_payload["attachment"]["analysis"]["label"] == "AI提示符合条件"
    assert upload_payload["invoice_id"]

    meta_response = client.get(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment/meta",
        headers=headers,
    )
    assert meta_response.status_code == 200
    meta_payload = meta_response.json()
    assert meta_payload["media_type"] == "image/png"
    assert meta_payload["analysis"]["headline"]

    content_response = client.get(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment",
        headers=headers,
    )
    assert content_response.status_code == 200
    assert content_response.content == file_bytes

    delete_response = client.delete(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment",
        headers=headers,
    )
    assert delete_response.status_code == 200
    assert delete_response.json()["invoice_id"] is None

    deleted_meta_response = client.get(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment/meta",
        headers=headers,
    )
    assert deleted_meta_response.status_code == 404


def test_claim_item_attachment_upload_flags_purpose_and_amount_mismatch(monkeypatch, tmp_path) -> None:
    def fake_recognize(
        self,
        files: list[tuple[str, bytes, str | None]],
    ) -> OcrRecognizeBatchRead:
        return OcrRecognizeBatchRead(
            total_file_count=1,
            success_count=1,
            documents=[
                OcrRecognizeDocumentRead(
                    filename="taxi-note.png",
                    media_type="image/png",
                    text="滴滴出行电子发票 金额120元 2026-05-13",
                    summary="识别到交通出行发票，金额 120 元。",
                    avg_score=0.97,
                    line_count=1,
                    page_count=1,
                    warnings=[],
                )
            ],
        )

    monkeypatch.setattr(OcrService, "recognize_files", fake_recognize)
    monkeypatch.setattr(ExpenseClaimService, "_get_attachment_storage_root", lambda self: tmp_path)

    client, session_factory = build_client()
    with session_factory() as db:
        claim, item = seed_claim(db)
        claim_id = claim.id
        item_id = item.id

    headers = {"x-auth-username": "emp-1", "x-auth-name": "Zhang San"}
    upload_response = client.post(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment",
        headers=headers,
        files=[("file", ("taxi-note.png", b"fake-image-bytes", "image/png"))],
    )

    assert upload_response.status_code == 200
    analysis = upload_response.json()["attachment"]["analysis"]
    assert analysis["severity"] == "high"
    assert any("金额字段" in point for point in analysis["points"])
    assert any("用途字段" in point for point in analysis["points"])


def test_claim_item_attachment_upload_flags_non_invoice_image_as_high_risk(monkeypatch, tmp_path) -> None:
    def fake_recognize(
        self,
        files: list[tuple[str, bytes, str | None]],
    ) -> OcrRecognizeBatchRead:
        return OcrRecognizeBatchRead(
            total_file_count=1,
            success_count=1,
            documents=[
                OcrRecognizeDocumentRead(
                    filename="random-image.png",
                    media_type="image/png",
                    text="",
                    summary="",
                    avg_score=0.0,
                    line_count=0,
                    page_count=1,
                    warnings=[],
                )
            ],
        )

    monkeypatch.setattr(OcrService, "recognize_files", fake_recognize)
    monkeypatch.setattr(ExpenseClaimService, "_get_attachment_storage_root", lambda self: tmp_path)

    client, session_factory = build_client()
    with session_factory() as db:
        claim, item = seed_claim(db)
        claim_id = claim.id
        item_id = item.id

    headers = {"x-auth-username": "emp-1", "x-auth-name": "Zhang San"}
    upload_response = client.post(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment",
        headers=headers,
        files=[("file", ("random-image.png", b"fake-image-bytes", "image/png"))],
    )

    assert upload_response.status_code == 200
    analysis = upload_response.json()["attachment"]["analysis"]
    assert analysis["severity"] == "high"
    assert any("附件内容" in point for point in analysis["points"])


def test_claim_item_delete_removes_item_and_attachment(monkeypatch, tmp_path) -> None:
    def fake_recognize(
        self,
        files: list[tuple[str, bytes, str | None]],
    ) -> OcrRecognizeBatchRead:
        return OcrRecognizeBatchRead(
            total_file_count=1,
            success_count=1,
            documents=[
                OcrRecognizeDocumentRead(
                    filename="office-note.png",
                    media_type="image/png",
                    text="办公用品发票 金额88元 2026-05-13",
                    summary="识别到办公用品发票，金额 88 元。",
                    avg_score=0.98,
                    line_count=1,
                    page_count=1,
                    warnings=[],
                )
            ],
        )

    monkeypatch.setattr(OcrService, "recognize_files", fake_recognize)
    monkeypatch.setattr(ExpenseClaimService, "_get_attachment_storage_root", lambda self: tmp_path)

    client, session_factory = build_client()
    with session_factory() as db:
        claim, item = seed_claim(db)
        claim_id = claim.id
        item_id = item.id

    headers = {"x-auth-username": "emp-1", "x-auth-name": "Zhang San"}
    upload_response = client.post(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment",
        headers=headers,
        files=[("file", ("office-note.png", b"fake-image-bytes", "image/png"))],
    )
    assert upload_response.status_code == 200
    assert (tmp_path / claim_id / item_id).exists()

    delete_response = client.delete(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}",
        headers=headers,
    )
    assert delete_response.status_code == 200
    assert delete_response.json()["item_id"] == item_id
    assert not (tmp_path / claim_id / item_id).exists()

    detail_response = client.get(
        f"/api/v1/reimbursements/claims/{claim_id}",
        headers=headers,
    )
    assert detail_response.status_code == 200
    detail_payload = detail_response.json()
    assert detail_payload["items"] == []
    assert detail_payload["invoice_count"] == 0
    assert detail_payload["employee_position"] == "招商主管"
    assert detail_payload["employee_grade"] == "P4"
    assert detail_payload["manager_name"] == "李总"
    assert detail_payload["role_labels"] == ["员工"]

    deleted_meta_response = client.get(
        f"/api/v1/reimbursements/claims/{claim_id}/items/{item_id}/attachment/meta",
        headers=headers,
    )
    assert deleted_meta_response.status_code == 404