"""개인경비 모듈 라우터.

- 경로: /expense
- 권한: 로그인 + `expense` 모듈 권한 필요 (관리자는 항상 통과).
- 데이터: ExpenseStore (JSON) 또는 ExpenseDBStore (PostgreSQL).
- 워크플로/첨부/집계/엑셀 내보내기는 DB 모드에서만 완전 지원.
"""

from __future__ import annotations

import io
import mimetypes
import os
import re
import uuid
from pathlib import Path
from typing import Any

from app.timezone import now_kst

from fastapi import (
    APIRouter,
    Depends,
    File,
    Form,
    HTTPException,
    Request,
    UploadFile,
)
from fastapi.responses import (
    FileResponse,
    HTMLResponse,
    JSONResponse,
    RedirectResponse,
    StreamingResponse,
)
from pydantic import BaseModel, Field

from .store import CATEGORIES, METHODS, STATUSES, ExpenseStore

router = APIRouter(prefix="/expense", tags=["expense"])

# 첨부 파일 정책
ALLOWED_EXTS = {
    ".pdf", ".png", ".jpg", ".jpeg", ".webp", ".gif",
    ".heic", ".tif", ".tiff",
    ".doc", ".docx", ".xls", ".xlsx", ".ppt", ".pptx",
    ".hwp", ".hwpx", ".txt", ".csv", ".zip",
}
MAX_UPLOAD_BYTES = 20 * 1024 * 1024  # 20MB


def _store(request: Request) -> Any:
    store = getattr(request.app.state, "expense_store", None)
    if store is None:
        raise RuntimeError("ExpenseStore 가 app.state 에 등록되지 않았습니다.")
    return store


def _upload_dir(request: Request) -> Path:
    """첨부 저장 루트. DATA_DIR/uploads/expense — DATA_DIR 와 같은 볼륨에 보관."""
    base = getattr(request.app.state, "data_dir", None)
    if base is None:
        base = Path(os.getenv("DATA_DIR", "/data"))
    root = Path(base) / "uploads" / "expense"
    root.mkdir(parents=True, exist_ok=True)
    return root


def _safe_filename(name: str) -> str:
    name = os.path.basename(name or "").strip() or "file"
    name = re.sub(r"[\\/:*?\"<>|\r\n\t]", "_", name)
    return name[:200]


def _require_user(request: Request) -> dict[str, Any]:
    from app.main import get_current_user_record  # noqa: WPS433
    from app.store import has_module  # noqa: WPS433

    user = get_current_user_record(request)
    if user is None:
        raise HTTPException(status_code=401, detail="로그인이 필요합니다.")
    if not has_module(user, "expense"):
        raise HTTPException(status_code=403, detail="개인경비 모듈 권한이 없습니다.")
    return user


def _require_approver(request: Request) -> dict[str, Any]:
    from app.main import get_current_user_record  # noqa: WPS433
    from app.store import has_module, is_admin  # noqa: WPS433

    user = get_current_user_record(request)
    if user is None:
        raise HTTPException(status_code=401, detail="로그인이 필요합니다.")
    if not (is_admin(user) or has_module(user, "expense_approver")):
        raise HTTPException(status_code=403, detail="개인경비 승인자 권한이 필요합니다.")
    return user


def _require_db_store(store: Any) -> None:
    """워크플로/첨부/집계는 DB 모드 전용. JSON 폴백에서는 501."""
    if not hasattr(store, "submit"):
        raise HTTPException(
            status_code=501,
            detail="이 기능은 expense_db (PostgreSQL) 모드에서만 지원됩니다. "
            "EXPENSE_DB_URL 환경변수를 설정하세요.",
        )


# ────────────────────────────────────────────────────────────
# Pydantic 모델
# ────────────────────────────────────────────────────────────
class ExpensePayload(BaseModel):
    spent_at: str = Field(..., description="YYYY-MM-DD")
    category: str
    method: str
    merchant: str = ""
    amount: int = Field(ge=0)
    memo: str = ""
    status: str | None = None


class RejectBody(BaseModel):
    reason: str


# ────────────────────────────────────────────────────────────
# 페이지
# ────────────────────────────────────────────────────────────
@router.get("/", response_class=HTMLResponse)
async def expense_index(request: Request) -> HTMLResponse:
    from app.main import (  # noqa: WPS433
        build_erp_nav,
        get_current_user_record,
        render_template,
    )
    from app.store import has_module, is_admin  # noqa: WPS433

    user = get_current_user_record(request)
    if user is None:
        return RedirectResponse(url="/login", status_code=303)
    if not has_module(user, "expense"):
        return render_template(
            request,
            "denied.html",
            {"reason": "개인경비 모듈 접근 권한이 없습니다."},
            status_code=403,
        )

    store = _store(request)
    items = sorted(
        store.list_for(user["email"]),
        key=lambda i: (i.get("spent_at", ""), i.get("created_at", "")),
        reverse=True,
    )
    summary = store.summary_for(user["email"])
    pending_count = 0
    is_approver = is_admin(user) or has_module(user, "expense_approver")
    if is_approver and hasattr(store, "list_pending_approval"):
        pending_count = len(store.list_pending_approval())

    return render_template(
        request,
        "expense/index.html",
        {
            "user": user,
            "is_admin": is_admin(user),
            "is_approver": is_approver,
            "pending_count": pending_count,
            "items": items,
            "summary": summary,
            "categories": list(CATEGORIES),
            "methods": list(METHODS),
            "statuses": list(STATUSES),
            "nav_items": build_erp_nav(user, active="expense"),
            "page_title": "개인경비",
            "page_subtitle": "법인카드 · 개인지출 · 정산 신청",
            "supports_workflow": hasattr(store, "submit"),
        },
    )


@router.get("/pending", response_class=HTMLResponse)
async def pending_page(request: Request) -> HTMLResponse:
    """승인자 대기열 — 제출 상태 항목 전체."""
    from app.main import (  # noqa: WPS433
        build_erp_nav,
        get_current_user_record,
        render_template,
    )
    from app.store import has_module, is_admin  # noqa: WPS433

    user = get_current_user_record(request)
    if user is None:
        return RedirectResponse(url="/login", status_code=303)
    if not (is_admin(user) or has_module(user, "expense_approver")):
        return render_template(
            request,
            "denied.html",
            {"reason": "개인경비 승인자 권한이 없습니다."},
            status_code=403,
        )
    store = _store(request)
    _require_db_store(store)
    pending = store.list_pending_approval()
    return render_template(
        request,
        "expense/pending.html",
        {
            "user": user,
            "is_admin": is_admin(user),
            "items": pending,
            "nav_items": build_erp_nav(user, active="expense"),
            "page_title": "개인경비 — 승인 대기",
            "page_subtitle": f"제출 상태 {len(pending)}건",
        },
    )


@router.get("/reports", response_class=HTMLResponse)
async def reports_page(request: Request) -> HTMLResponse:
    """월별/카테고리별 집계."""
    from app.main import (  # noqa: WPS433
        build_erp_nav,
        get_current_user_record,
        render_template,
    )
    from app.store import is_admin  # noqa: WPS433

    user = get_current_user_record(request)
    if user is None:
        return RedirectResponse(url="/login", status_code=303)
    store = _store(request)
    _require_db_store(store)
    year_str = request.query_params.get("year") or str(now_kst().year)
    try:
        year = int(year_str)
    except ValueError:
        year = now_kst().year
    rows = store.monthly_summary(email=user["email"], year=year)

    # 피벗: month → {category → total}
    months: dict[str, dict[str, int]] = {}
    for r in rows:
        months.setdefault(r["month"], {})[r["category"]] = r["total"]
    month_keys = sorted(months.keys())
    cat_totals = {c: sum(months[m].get(c, 0) for m in month_keys) for c in CATEGORIES}
    grand_total = sum(cat_totals.values())

    return render_template(
        request,
        "expense/reports.html",
        {
            "user": user,
            "is_admin": is_admin(user),
            "year": year,
            "months": month_keys,
            "pivot": months,
            "categories": list(CATEGORIES),
            "cat_totals": cat_totals,
            "grand_total": grand_total,
            "nav_items": build_erp_nav(user, active="expense"),
            "page_title": "개인경비 — 집계",
            "page_subtitle": f"{year}년 월별/카테고리별",
        },
    )


# ────────────────────────────────────────────────────────────
# 항목 CRUD API
# ────────────────────────────────────────────────────────────
@router.get("/api/items")
async def list_items(
    request: Request,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    store = _store(request)
    return JSONResponse(
        {
            "items": store.list_for(user["email"]),
            "summary": store.summary_for(user["email"]),
        }
    )


@router.post("/api/items")
async def create_item(
    request: Request,
    body: ExpensePayload,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    item = _store(request).create(owner=user["email"], payload=body.model_dump())
    return JSONResponse({"item": item}, status_code=201)


@router.put("/api/items/{item_id}")
async def update_item(
    request: Request,
    item_id: str,
    body: ExpensePayload,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    store = _store(request)
    # 워크플로 모드: 작성중/반려 상태에서만 수정 가능
    if hasattr(store, "get"):
        current = store.get(item_id=item_id, owner=user["email"])
        if current and current.get("status") not in ("작성중", "반려"):
            raise HTTPException(
                status_code=409,
                detail=f"{current['status']} 상태에서는 수정할 수 없습니다.",
            )
    try:
        item = store.update(
            item_id=item_id, owner=user["email"], payload=body.model_dump()
        )
    except KeyError:
        raise HTTPException(status_code=404, detail="항목을 찾을 수 없습니다.")
    return JSONResponse({"item": item})


@router.delete("/api/items/{item_id}")
async def delete_item(
    request: Request,
    item_id: str,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    store = _store(request)
    if hasattr(store, "get"):
        current = store.get(item_id=item_id, owner=user["email"])
        if current and current.get("status") not in ("작성중", "반려"):
            raise HTTPException(
                status_code=409,
                detail=f"{current['status']} 상태에서는 삭제할 수 없습니다.",
            )
    try:
        _store(request).delete(item_id=item_id, owner=user["email"])
    except KeyError:
        raise HTTPException(status_code=404, detail="항목을 찾을 수 없습니다.")
    return JSONResponse({"ok": True})


# ────────────────────────────────────────────────────────────
# 워크플로 API
# ────────────────────────────────────────────────────────────
@router.post("/api/items/{item_id}/submit")
async def submit_item(
    request: Request,
    item_id: str,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    store = _store(request)
    _require_db_store(store)
    try:
        item = store.submit(item_id=item_id, owner=user["email"])
    except ValueError as exc:
        raise HTTPException(status_code=409, detail=str(exc))
    return JSONResponse({"item": item})


@router.post("/api/items/{item_id}/revert")
async def revert_item(
    request: Request,
    item_id: str,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    store = _store(request)
    _require_db_store(store)
    try:
        item = store.revert_to_draft(item_id=item_id, owner=user["email"])
    except ValueError as exc:
        raise HTTPException(status_code=409, detail=str(exc))
    return JSONResponse({"item": item})


@router.post("/api/items/{item_id}/approve")
async def approve_item(
    request: Request,
    item_id: str,
    user: dict[str, Any] = Depends(_require_approver),
) -> JSONResponse:
    store = _store(request)
    _require_db_store(store)
    try:
        item = store.approve(item_id=item_id, approver_email=user["email"])
    except ValueError as exc:
        raise HTTPException(status_code=409, detail=str(exc))
    return JSONResponse({"item": item})


@router.post("/api/items/{item_id}/reject")
async def reject_item(
    request: Request,
    item_id: str,
    body: RejectBody,
    user: dict[str, Any] = Depends(_require_approver),
) -> JSONResponse:
    store = _store(request)
    _require_db_store(store)
    try:
        item = store.reject(
            item_id=item_id, approver_email=user["email"], reason=body.reason
        )
    except ValueError as exc:
        raise HTTPException(status_code=409, detail=str(exc))
    return JSONResponse({"item": item})


@router.post("/api/items/{item_id}/settle")
async def settle_item(
    request: Request,
    item_id: str,
    user: dict[str, Any] = Depends(_require_approver),
) -> JSONResponse:
    store = _store(request)
    _require_db_store(store)
    try:
        item = store.settle(item_id=item_id, approver_email=user["email"])
    except ValueError as exc:
        raise HTTPException(status_code=409, detail=str(exc))
    return JSONResponse({"item": item})


# ────────────────────────────────────────────────────────────
# 첨부 API
# ────────────────────────────────────────────────────────────
@router.get("/api/items/{item_id}/attachments")
async def list_attachments(
    request: Request,
    item_id: str,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    from app.store import has_module, is_admin  # noqa: WPS433

    store = _store(request)
    _require_db_store(store)
    item = store.get_any(item_id=item_id)
    if not item:
        raise HTTPException(status_code=404, detail="항목 없음")
    # 본인 또는 승인자/관리자만 조회
    if item["owner"] != user["email"] and not (
        is_admin(user) or has_module(user, "expense_approver")
    ):
        raise HTTPException(status_code=403, detail="조회 권한 없음")
    return JSONResponse({"attachments": store.list_attachments(item_id=item_id)})


@router.post("/api/items/{item_id}/attachments")
async def upload_attachment(
    request: Request,
    item_id: str,
    kind: str = Form("receipt"),
    file: UploadFile = File(...),
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    store = _store(request)
    _require_db_store(store)

    if kind not in ("receipt", "other"):
        raise HTTPException(status_code=400, detail="kind 는 receipt|other")

    item = store.get(item_id=item_id, owner=user["email"])
    if not item:
        raise HTTPException(status_code=404, detail="항목 없음")
    if item["status"] not in ("작성중", "반려"):
        raise HTTPException(
            status_code=409,
            detail=f"{item['status']} 상태에서는 첨부할 수 없습니다.",
        )

    raw_name = _safe_filename(file.filename or "")
    ext = os.path.splitext(raw_name)[1].lower()
    if ext and ext not in ALLOWED_EXTS:
        raise HTTPException(
            status_code=415,
            detail=f"허용되지 않는 확장자: {ext}",
        )

    # 디스크에 저장 (스트리밍, 사이즈 제한)
    att_id = uuid.uuid4().hex[:12]
    sub_dir = _upload_dir(request) / item_id
    sub_dir.mkdir(parents=True, exist_ok=True)
    stored_name = f"{att_id}_{raw_name}"
    stored_path = sub_dir / stored_name

    size_total = 0
    chunk_size = 1024 * 256
    try:
        with stored_path.open("wb") as out:
            while True:
                chunk = await file.read(chunk_size)
                if not chunk:
                    break
                size_total += len(chunk)
                if size_total > MAX_UPLOAD_BYTES:
                    out.close()
                    stored_path.unlink(missing_ok=True)
                    raise HTTPException(
                        status_code=413,
                        detail=f"파일 크기 초과 (최대 {MAX_UPLOAD_BYTES // (1024*1024)}MB)",
                    )
                out.write(chunk)
    finally:
        await file.close()

    content_type = (
        file.content_type
        or mimetypes.guess_type(raw_name)[0]
        or "application/octet-stream"
    )

    rec = store.add_attachment(
        item_id=item_id,
        owner=user["email"],
        kind=kind,
        filename=raw_name,
        stored_path=str(stored_path),
        content_type=content_type,
        size_bytes=size_total,
    )
    return JSONResponse({"attachment": rec}, status_code=201)


@router.get("/api/attachments/{att_id}")
async def download_attachment(
    request: Request,
    att_id: str,
    user: dict[str, Any] = Depends(_require_user),
) -> FileResponse:
    from app.store import has_module, is_admin  # noqa: WPS433

    store = _store(request)
    _require_db_store(store)
    rec = store.get_attachment(att_id=att_id)
    if not rec:
        raise HTTPException(status_code=404, detail="첨부 없음")
    item = store.get_any(item_id=rec["item_id"])
    if not item:
        raise HTTPException(status_code=404, detail="항목 없음")
    if item["owner"] != user["email"] and not (
        is_admin(user) or has_module(user, "expense_approver")
    ):
        raise HTTPException(status_code=403, detail="조회 권한 없음")

    path = Path(rec["stored_path"])
    if not path.exists():
        raise HTTPException(status_code=410, detail="파일이 사라졌습니다.")
    return FileResponse(
        path=str(path),
        filename=rec["filename"],
        media_type=rec["content_type"],
    )


@router.delete("/api/attachments/{att_id}")
async def delete_attachment(
    request: Request,
    att_id: str,
    user: dict[str, Any] = Depends(_require_user),
) -> JSONResponse:
    store = _store(request)
    _require_db_store(store)
    try:
        rec = store.delete_attachment(att_id=att_id, owner=user["email"])
    except KeyError:
        raise HTTPException(status_code=404, detail="첨부 없음")
    # 파일 정리 (실패해도 DB 삭제는 유효 — 고아 파일 남을 수 있으니 로그만)
    try:
        Path(rec["stored_path"]).unlink(missing_ok=True)
    except OSError:
        pass
    return JSONResponse({"ok": True})


# ────────────────────────────────────────────────────────────
# 엑셀 내보내기
# ────────────────────────────────────────────────────────────
@router.get("/api/export.xlsx")
async def export_xlsx(
    request: Request,
    user: dict[str, Any] = Depends(_require_user),
) -> StreamingResponse:
    from app.store import has_module, is_admin  # noqa: WPS433
    from openpyxl import Workbook  # 지연 import

    store = _store(request)
    _require_db_store(store)

    date_from = request.query_params.get("from")
    date_to = request.query_params.get("to")
    scope = request.query_params.get("scope", "mine")

    target_email: str | None = user["email"]
    if scope == "all":
        if not (is_admin(user) or has_module(user, "expense_approver")):
            raise HTTPException(status_code=403, detail="전체 내보내기 권한 없음")
        target_email = None

    rows = store.list_for_export(
        email=target_email, date_from=date_from, date_to=date_to
    )

    wb = Workbook()
    ws = wb.active
    ws.title = "expense"
    header = [
        "사용일", "소유자", "분류", "결제수단", "가맹점",
        "금액", "메모", "상태", "승인자", "결재일시", "반려사유",
        "생성일시", "수정일시",
    ]
    ws.append(header)
    for r in rows:
        ws.append([
            r.get("spent_at", ""),
            r.get("owner", ""),
            r.get("category", ""),
            r.get("method", ""),
            r.get("merchant", ""),
            int(r.get("amount", 0)),
            r.get("memo", ""),
            r.get("status", ""),
            r.get("approver_email", "") or "",
            r.get("decided_at", "") or "",
            r.get("reject_reason", "") or "",
            r.get("created_at", ""),
            r.get("updated_at", ""),
        ])
    # 컬럼 너비 대충
    widths = [12, 28, 10, 12, 24, 12, 30, 10, 24, 22, 24, 22, 22]
    for col, w in enumerate(widths, start=1):
        ws.column_dimensions[ws.cell(row=1, column=col).column_letter].width = w

    buf = io.BytesIO()
    wb.save(buf)
    buf.seek(0)

    fname_scope = "all" if target_email is None else "mine"
    fname = f"expense_{fname_scope}_{now_kst().strftime('%Y%m%d_%H%M%S')}.xlsx"
    return StreamingResponse(
        buf,
        media_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        headers={"Content-Disposition": f'attachment; filename="{fname}"'},
    )


@router.get("/health")
async def health() -> dict[str, str]:
    return {"status": "ok", "module": "expense"}