import json
from pathlib import Path

import pandas as pd
from fastapi import APIRouter, HTTPException

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

_DATA_DIR = Path(__file__).parent / "data"

with (_DATA_DIR / "member_insights.json").open() as f:
    _MEMBER_INSIGHTS = json.load(f)

_SCHEDULE_TEXT = (_DATA_DIR / "schedule_response.txt").read_text(encoding="utf-8").strip()

_HISTORICAL = pd.read_csv(_DATA_DIR / "historical_procedures.csv")
_AVAILABLE = pd.read_csv(_DATA_DIR / "available_procedures.csv")


_OPS = {
    "equals": lambda s, v: s == v,
    "ne": lambda s, v: s != v,
    "contains": lambda s, v: s.astype(str).str.contains(str(v), case=False, na=False),
    "gt": lambda s, v: s > v,
    "lt": lambda s, v: s < v,
    "ge": lambda s, v: s >= v,
    "le": lambda s, v: s <= v,
}


def _apply_filters_and_group(df: pd.DataFrame, filters_raw, group_by_raw) -> list[dict]:
    try:
        filters = json.loads(filters_raw) if isinstance(filters_raw, str) else (filters_raw or [])
        group_by = json.loads(group_by_raw) if isinstance(group_by_raw, str) else (group_by_raw or [])
    except json.JSONDecodeError as exc:
        raise HTTPException(status_code=400, detail=f"Invalid JSON in filters or group_by: {exc}")

    result = df.copy()
    for f in filters:
        col, op, val = f.get("column"), f.get("operator"), f.get("value")
        if col not in result.columns:
            raise HTTPException(status_code=400, detail=f"Unknown column: {col}")
        if op not in _OPS:
            raise HTTPException(status_code=400, detail=f"Unsupported operator: {op}")
        result = result[_OPS[op](result[col], val)]

    if group_by:
        missing = [c for c in group_by if c not in result.columns]
        if missing:
            raise HTTPException(status_code=400, detail=f"Unknown group_by columns: {missing}")
        numeric_cols = result.select_dtypes(include="number").columns.tolist()
        result = result.groupby(group_by)[numeric_cols].mean().reset_index()

    return result.to_dict(orient="records")


@router.get("/member-insights")
def member_insights():
    return _MEMBER_INSIGHTS


@router.get("/schedule")
def schedule():
    return {"result": _SCHEDULE_TEXT}


@router.post("/historical-procedures")
def historical_procedures(payload: dict):
    rows = _apply_filters_and_group(
        _HISTORICAL,
        payload.get("filters", "[]"),
        payload.get("group_by", "[]"),
    )
    return {"result": rows}


@router.post("/available-procedures")
def available_procedures(payload: dict):
    rows = _apply_filters_and_group(
        _AVAILABLE,
        payload.get("filters", "[]"),
        payload.get("group_by", "[]"),
    )
    return {"result": rows}