from __future__ import annotations

import re
from collections import defaultdict
from datetime import UTC, date, datetime
from typing import TYPE_CHECKING, Annotated, Any
from urllib.parse import quote

from fastapi import APIRouter, Depends, HTTPException, Query, Request
from fastapi.responses import HTMLResponse, JSONResponse
from starlette import status

from app.auth import get_current_user
from app.core.dependencies import get_services
from app.models import UserInDB
from app.routes.history import build_user_histories_snapshot
from app.routes.shell_navigation import build_shell_context
from app.services.case_deletion_service import CaseDeletionError


if TYPE_CHECKING:
    from app.core.services import AppServices
else:
    AppServices = Any


router = APIRouter()
CurrentUser = Annotated[UserInDB, Depends(get_current_user)]
ServicesDep = Annotated[AppServices, Depends(get_services)]
_DIGITS_PATTERN = re.compile(r"\D+")
_CASE_FILTER_STATUS = {"completado", "pendiente", "procesando", "en_cola"}
_RIPS_FILTER_STATUS = {"sin_rips", "rips_listo", "rips_con_observaciones"}
_DOC_COUNT_RANGES = {"1-2", "3-5", "6+"}
_EPICRISIS_PDF_FILTERS = {"yes", "no"}


def _normalize_digits(value: Any) -> str:
    return _DIGITS_PATTERN.sub("", str(value or ""))


def _safe_iso_to_datetime(value: Any) -> datetime:
    if not value:
        return datetime.min.replace(tzinfo=UTC)
    try:
        parsed = datetime.fromisoformat(str(value))
    except ValueError:
        return datetime.min.replace(tzinfo=UTC)
    if parsed.tzinfo is None:
        return parsed.replace(tzinfo=UTC)
    return parsed.astimezone(UTC)


def _safe_iso_to_date(value: str | None) -> date | None:
    if not value:
        return None
    try:
        return date.fromisoformat(str(value))
    except ValueError:
        return None


def _normalize_case_key(value: str) -> str:
    normalized = str(value or "").strip()
    if not normalized:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="El parámetro 'case_key' es obligatorio.",
        )
    return normalized


def _humanize_document_type(document_type: str) -> str:
    normalized = str(document_type or "sin_tipo").replace("_", " ").strip()
    if not normalized:
        return "Sin tipo"
    return normalized[:1].upper() + normalized[1:]


def _build_case_history_href(case_group: dict[str, Any], *, fallback_document_id: str = "") -> str:
    case_key = str(case_group.get("case_key") or "").strip()
    document_id = str(fallback_document_id or "").strip()
    if case_key:
        href = f"/casos?case_key={quote(case_key)}"
        if document_id:
            href = f"{href}&documento_id={quote(document_id)}"
        return href
    return "/casos"


def _build_case_actions(case_group: dict[str, Any], *, document_id: str = "") -> list[dict[str, str]]:
    case_key = str(case_group.get("case_key") or "").strip()
    epicrisis_status = str(case_group.get("epicrisis_status") or "").strip().lower()
    epicrisis_label = "Ver epicrisis" if epicrisis_status == "completado" else "Generar epicrisis"
    actions = [
        {
            "label": "Ver detalle",
            "href": _build_case_history_href(case_group, fallback_document_id=document_id),
            "variant": "secondary",
        }
    ]
    if not case_key:
        return actions

    actions.extend(
        [
            {
                "label": epicrisis_label,
                "href": str(case_group.get("epicrisis_url") or f"/epicrisis?case_key={quote(case_key)}"),
                "variant": "primary",
            },
            {
                "label": "RIPS",
                "href": f"/rips/operativo?case_key={quote(case_key)}",
                "variant": "secondary",
            },
            {
                "label": "PDF",
                "href": f"/epicrisis/pdf_cache/ultimo?case_key={quote(case_key)}",
                "variant": "ghost",
            },
        ]
    )
    return actions


def _load_latest_rips_lookup(
    *,
    username: str,
    services: AppServices,
    case_keys: list[str],
) -> dict[str, dict[str, Any]]:
    normalized_case_keys = [str(case_key or "").strip() for case_key in case_keys if str(case_key or "").strip()]
    if not normalized_case_keys:
        return {}

    results = services.mongo_analyses.collection.find(
        {
            "usuario": username,
            "tipo_documento": "rips_case_payload",
            "case_key": {"$in": normalized_case_keys},
        }
    ).sort([("case_key", 1), ("version", -1), ("fecha_analisis", -1)])

    lookup: dict[str, dict[str, Any]] = {}
    for item in results:
        case_key = str(item.get("case_key") or "").strip()
        if not case_key or case_key in lookup:
            continue
        lookup[case_key] = dict(item)
    return lookup


def _derive_rips_status(rips_payload: dict[str, Any] | None) -> str:
    if not rips_payload:
        return "sin_rips"
    if bool(rips_payload.get("ready_for_cuv")):
        return "rips_listo"
    return "rips_con_observaciones"


def _build_rips_meta(rips_payload: dict[str, Any] | None) -> dict[str, Any]:
    status = _derive_rips_status(rips_payload)
    updated_at = (rips_payload or {}).get("fecha_analisis")
    label_map = {
        "sin_rips": "Sin RIPS",
        "rips_listo": "RIPS listo",
        "rips_con_observaciones": "RIPS con observaciones",
    }
    return {
        "status": status,
        "label": label_map[status],
        "ready_for_cuv": bool((rips_payload or {}).get("ready_for_cuv")),
        "version": int((rips_payload or {}).get("version") or 0) or None,
        "reject_count": int((rips_payload or {}).get("reject_count") or 0),
        "notify_count": int((rips_payload or {}).get("notify_count") or 0),
        "updated_at": (
            updated_at.isoformat() if isinstance(updated_at, datetime) else str(updated_at or "")
        ),
    }


def _normalize_case_groups(snapshot: dict[str, Any]) -> tuple[list[dict[str, Any]], int]:
    cases: list[dict[str, Any]] = []
    legacy_excluded_count = 0
    for case_group in snapshot.get("historias_por_caso", {}).values():
        case_key = str(case_group.get("case_key") or "").strip()
        if not case_key:
            legacy_excluded_count += 1
            continue
        cases.append(case_group)
    return cases, legacy_excluded_count


def _build_case_summary(case_group: dict[str, Any], *, rips_payload: dict[str, Any] | None) -> dict[str, Any]:
    documents = list(case_group.get("documentos") or [])
    latest_doc = documents[0] if documents else {}
    latest_at = str(latest_doc.get("fecha_analisis") or "")
    epicrisis_status = str(case_group.get("epicrisis_status") or "pendiente")
    rips = _build_rips_meta(rips_payload)
    return {
        "case_key": str(case_group.get("case_key") or "").strip(),
        "case_number": str(case_group.get("case_number") or "").strip() or "Sin número",
        "patient_name": str(case_group.get("patient_name") or "Paciente sin nombre"),
        "patient_id": str(case_group.get("patient_id") or "").strip(),
        "document_count": len(documents),
        "document_types": list(case_group.get("tipos_documento") or []),
        "updated_at": latest_at,
        "epicrisis_status": epicrisis_status,
        "ready_for_epicrisis": bool(case_group.get("ready_for_epicrisis", False)),
        "epicrisis_rule_status": str(case_group.get("epicrisis_rule_status") or ""),
        "epicrisis_blocking_reason": str(case_group.get("epicrisis_blocking_reason") or ""),
        "epicrisis_missing_documents": list(case_group.get("epicrisis_missing_documents") or []),
        "epicrisis_url": str(case_group.get("epicrisis_url") or f"/epicrisis?case_key={quote(str(case_group.get('case_key') or '').strip())}"),
        "has_epicrisis_pdf": epicrisis_status == "completado",
        "rips": rips,
        "actions": _build_case_actions(case_group, document_id=str(latest_doc.get("_id") or "").strip()),
    }


def _matches_document_count_range(document_count: int, value: str) -> bool:
    if value == "1-2":
        return 1 <= document_count <= 2
    if value == "3-5":
        return 3 <= document_count <= 5
    if value == "6+":
        return document_count >= 6
    return True


def _filter_case_summaries(
    case_summaries: list[dict[str, Any]],
    *,
    q: str,
    epicrisis_status: str,
    document_type: str,
    rips_status: str,
    document_count_range: str,
    has_epicrisis_pdf: str,
    updated_from: str,
    updated_to: str,
) -> list[dict[str, Any]]:
    normalized_query = str(q or "").strip().lower()
    normalized_epicrisis_status = str(epicrisis_status or "").strip().lower()
    normalized_document_type = str(document_type or "").strip().lower()
    normalized_rips_status = str(rips_status or "").strip().lower()
    normalized_document_count_range = str(document_count_range or "").strip()
    normalized_pdf_filter = str(has_epicrisis_pdf or "").strip().lower()
    from_date = _safe_iso_to_date(updated_from)
    to_date = _safe_iso_to_date(updated_to)
    query_digits = _normalize_digits(normalized_query)

    filtered: list[dict[str, Any]] = []
    for item in case_summaries:
        patient_id_digits = _normalize_digits(item.get("patient_id"))
        search_blob = " ".join(
            [
                str(item.get("case_number") or "").lower(),
                str(item.get("case_key") or "").lower(),
                str(item.get("patient_name") or "").lower(),
            ]
        )
        if normalized_query and normalized_query not in search_blob and (
            not query_digits or query_digits not in patient_id_digits
        ):
            continue

        if (
            normalized_epicrisis_status
            and normalized_epicrisis_status in _CASE_FILTER_STATUS
            and str(item.get("epicrisis_status") or "").strip().lower() != normalized_epicrisis_status
        ):
            continue

        if normalized_document_type:
            available_document_types = {str(doc_type or "").strip().lower() for doc_type in item.get("document_types") or []}
            if normalized_document_type not in available_document_types:
                continue

        if (
            normalized_rips_status
            and normalized_rips_status in _RIPS_FILTER_STATUS
            and str(((item.get("rips") or {}).get("status")) or "").strip().lower() != normalized_rips_status
        ):
            continue

        if (
            normalized_document_count_range
            and normalized_document_count_range in _DOC_COUNT_RANGES
            and not _matches_document_count_range(int(item.get("document_count") or 0), normalized_document_count_range)
        ):
            continue

        has_pdf = bool(item.get("has_epicrisis_pdf"))
        if (
            normalized_pdf_filter
            and normalized_pdf_filter in _EPICRISIS_PDF_FILTERS
            and (
                (normalized_pdf_filter == "yes" and not has_pdf)
                or (normalized_pdf_filter == "no" and has_pdf)
            )
        ):
            continue

        updated_at = _safe_iso_to_datetime(item.get("updated_at"))
        updated_date = updated_at.date() if updated_at != datetime.min else None
        if from_date and (updated_date is None or updated_date < from_date):
            continue
        if to_date and (updated_date is None or updated_date > to_date):
            continue

        filtered.append(item)

    return sorted(filtered, key=lambda current: _safe_iso_to_datetime(current.get("updated_at")), reverse=True)


def _build_case_list_payload(
    *,
    username: str,
    services: AppServices,
    q: str = "",
    epicrisis_status: str = "",
    document_type: str = "",
    rips_status: str = "",
    document_count_range: str = "",
    has_epicrisis_pdf: str = "",
    updated_from: str = "",
    updated_to: str = "",
) -> dict[str, Any]:
    snapshot = build_user_histories_snapshot(username=username, services=services)
    normalized_cases, legacy_excluded_count = _normalize_case_groups(snapshot)
    case_keys = [str(case_group.get("case_key") or "").strip() for case_group in normalized_cases]
    rips_lookup = _load_latest_rips_lookup(username=username, services=services, case_keys=case_keys)

    all_case_summaries = [
        _build_case_summary(case_group, rips_payload=rips_lookup.get(str(case_group.get("case_key") or "").strip()))
        for case_group in normalized_cases
    ]
    filtered_cases = _filter_case_summaries(
        all_case_summaries,
        q=q,
        epicrisis_status=epicrisis_status,
        document_type=document_type,
        rips_status=rips_status,
        document_count_range=document_count_range,
        has_epicrisis_pdf=has_epicrisis_pdf,
        updated_from=updated_from,
        updated_to=updated_to,
    )
    available_document_types = sorted(
        {
            str(document_type or "").strip()
            for case_item in all_case_summaries
            for document_type in case_item.get("document_types") or []
            if str(document_type or "").strip()
        }
    )

    return {
        "summary": {
            "total_cases": len(all_case_summaries),
            "filtered_cases": len(filtered_cases),
            "total_documents": sum(int(item.get("document_count") or 0) for item in all_case_summaries),
            "filtered_documents": sum(int(item.get("document_count") or 0) for item in filtered_cases),
            "completed_epicrisis": sum(
                1 for item in filtered_cases if str(item.get("epicrisis_status") or "").strip().lower() == "completado"
            ),
            "rips_ready": sum(
                1 for item in filtered_cases if str(((item.get("rips") or {}).get("status")) or "") == "rips_listo"
            ),
            "legacy_excluded_count": legacy_excluded_count,
            "available_document_types": available_document_types,
        },
        "filters": {
            "q": str(q or ""),
            "epicrisis_status": str(epicrisis_status or ""),
            "document_type": str(document_type or ""),
            "rips_status": str(rips_status or ""),
            "document_count_range": str(document_count_range or ""),
            "has_epicrisis_pdf": str(has_epicrisis_pdf or ""),
            "updated_from": str(updated_from or ""),
            "updated_to": str(updated_to or ""),
        },
        "cases": filtered_cases,
        "empty": not filtered_cases,
    }


def _build_case_detail_payload(*, username: str, services: AppServices, case_key: str) -> dict[str, Any]:
    snapshot = build_user_histories_snapshot(username=username, services=services)
    normalized_case_key = _normalize_case_key(case_key)
    case_group = next(
        (
            item
            for item in snapshot.get("historias_por_caso", {}).values()
            if str(item.get("case_key") or "").strip() == normalized_case_key
        ),
        None,
    )
    if case_group is None:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Caso no encontrado o no disponible en la bandeja actual.",
        )

    rips_lookup = _load_latest_rips_lookup(username=username, services=services, case_keys=[normalized_case_key])
    case_summary = _build_case_summary(case_group, rips_payload=rips_lookup.get(normalized_case_key))
    documents_by_type: dict[str, list[dict[str, Any]]] = defaultdict(list)
    for document in case_group.get("documentos") or []:
        current_type = str(document.get("tipo_documento") or "sin_tipo")
        documents_by_type[current_type].append(
            {
                "document_id": str(document.get("_id") or "").strip(),
                "name": str(document.get("nombre_archivo") or "Documento"),
                "type": current_type,
                "type_label": _humanize_document_type(current_type),
                "document_title": str(document.get("document_title") or "").strip(),
                "updated_at": str(document.get("fecha_analisis") or ""),
                "href": _build_case_history_href(case_group, fallback_document_id=str(document.get("_id") or "").strip()),
                "analysis_available": bool(
                    document.get("analysis_structured") or document.get("analisis_html") or document.get("analisis")
                ),
            }
        )

    grouped_documents = [
        {
            "type": document_type,
            "type_label": _humanize_document_type(document_type),
            "count": len(items),
            "documents": sorted(items, key=lambda item: _safe_iso_to_datetime(item.get("updated_at")), reverse=True),
        }
        for document_type, items in sorted(documents_by_type.items(), key=lambda current: current[0])
    ]

    return {
        "case": case_summary,
        "document_groups": grouped_documents,
    }


@router.get("/casos", response_class=HTMLResponse)
async def cases_page(
    request: Request,
    user: CurrentUser,
    services: ServicesDep,
    case_key: Annotated[str | None, Query()] = None,
    documento_id: Annotated[str | None, Query()] = None,
):
    return services.templates.TemplateResponse(
        request,
        "cases.html",
        {
            "request": request,
            "user": user,
            "initial_case_key": str(case_key or "").strip(),
            "initial_documento_id": str(documento_id or "").strip(),
            **build_shell_context(request=request, user=user),
        },
    )


@router.get("/api/casos")
async def list_cases(
    user: CurrentUser,
    services: ServicesDep,
    q: Annotated[str, Query(max_length=120)] = "",
    epicrisis_status: Annotated[str, Query(max_length=32)] = "",
    document_type: Annotated[str, Query(max_length=64)] = "",
    rips_status: Annotated[str, Query(max_length=64)] = "",
    document_count_range: Annotated[str, Query(max_length=16)] = "",
    has_epicrisis_pdf: Annotated[str, Query(max_length=16)] = "",
    updated_from: Annotated[str, Query(max_length=10)] = "",
    updated_to: Annotated[str, Query(max_length=10)] = "",
) -> JSONResponse:
    payload = _build_case_list_payload(
        username=user.username,
        services=services,
        q=q,
        epicrisis_status=epicrisis_status,
        document_type=document_type,
        rips_status=rips_status,
        document_count_range=document_count_range,
        has_epicrisis_pdf=has_epicrisis_pdf,
        updated_from=updated_from,
        updated_to=updated_to,
    )
    return JSONResponse(content=payload)


@router.get("/api/casos/{case_key}")
async def case_detail(
    case_key: str,
    user: CurrentUser,
    services: ServicesDep,
) -> JSONResponse:
    payload = _build_case_detail_payload(username=user.username, services=services, case_key=case_key)
    return JSONResponse(content=payload)


@router.delete("/api/casos/documentos/{document_id}")
async def delete_case_document(
    document_id: str,
    user: CurrentUser,
    services: ServicesDep,
) -> JSONResponse:
    try:
        payload = services.case_deletion_service.delete_document(
            username=user.username,
            document_id=document_id,
        )
    except CaseDeletionError as exc:
        raise HTTPException(status_code=exc.status_code, detail=str(exc)) from exc
    return JSONResponse(content=payload)


@router.delete("/api/casos/{case_key}")
async def delete_case(
    case_key: str,
    user: CurrentUser,
    services: ServicesDep,
) -> JSONResponse:
    try:
        payload = services.case_deletion_service.delete_case(username=user.username, case_key=case_key)
    except CaseDeletionError as exc:
        raise HTTPException(status_code=exc.status_code, detail=str(exc)) from exc
    return JSONResponse(content=payload)
