"""
Superadmin API: Batch-Anreicherung von Übungen per KI (Skills, Kurzfassung, Anleitung).

# ACCESS_LAYER exempt: Plattform-weites Superadmin-Werkzeug ohne TenantContext.
Siehe ACCESS_LAYER_ENDPOINT_AUDIT.md.
"""
from __future__ import annotations

from concurrent.futures import ThreadPoolExecutor, as_completed
from typing import Any, Dict, List, Literal, Optional

from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel, Field, field_validator

from auth import require_auth
from club_tenancy import is_superadmin
from db import get_cursor, get_db, r2d
from exercise_enrichment import (
    DEFAULT_SET_STATUS,
    MAX_BATCH_EXERCISES,
    MAX_PREVIEW_BATCH_EXERCISES,
    SKILL_MERGE_MODES,
    SkillMergeMode,
    apply_exercise_enrichment,
    estimate_llm_calls,
    preview_exercise_enrichment,
)

_PREVIEW_MAX_WORKERS = 3

router = APIRouter(tags=["admin_exercise_enrichment"])

_VALID_STATUS_FILTER = frozenset({"draft", "in_review", "approved", "archived"})
_VALID_VISIBILITY = frozenset({"private", "club", "official", "all"})
_MAX_CANDIDATES_LIMIT = 100
_MAX_ANALYZE_IDS = 10_000


def _require_superadmin(session: dict) -> dict:
    role = (session.get("role") or "").strip().lower()
    if not is_superadmin(role):
        raise HTTPException(status_code=403, detail="Nur Superadmins")
    return session


def _normalize_id_list(raw: Optional[List[int]], *, max_items: Optional[int] = None) -> List[int]:
    if not raw:
        return []
    seen: set[int] = set()
    out: List[int] = []
    for x in raw:
        try:
            xi = int(x)
        except (TypeError, ValueError):
            continue
        if xi < 1 or xi in seen:
            continue
        seen.add(xi)
        out.append(xi)
        if max_items is not None and len(out) >= max_items:
            break
    return out


def _build_candidates_where(
    *,
    status: str,
    visibility: Optional[str],
    focus_area_id: Optional[int],
    without_skills: bool,
    with_ai_suggested_skills: bool,
) -> tuple[list[str], list[Any]]:
    st = (status or "draft").strip().lower()
    if st not in _VALID_STATUS_FILTER:
        raise HTTPException(status_code=400, detail="Ungültiger Status-Filter")

    where: List[str] = ["e.status = %s"]
    params: List[Any] = [st]

    vis_raw = (visibility or "private").strip().lower()
    if vis_raw and vis_raw != "all":
        if vis_raw not in _VALID_VISIBILITY - {"all"}:
            raise HTTPException(status_code=400, detail="Ungültiger Visibility-Filter")
        where.append("e.visibility = %s")
        params.append(vis_raw)

    if focus_area_id is not None:
        where.append(
            "EXISTS (SELECT 1 FROM exercise_focus_areas efa "
            "WHERE efa.exercise_id = e.id AND efa.focus_area_id = %s)"
        )
        params.append(int(focus_area_id))

    if without_skills:
        where.append(
            "NOT EXISTS (SELECT 1 FROM exercise_skills es WHERE es.exercise_id = e.id)"
        )

    if with_ai_suggested_skills:
        where.append(
            "EXISTS (SELECT 1 FROM exercise_skills es "
            "WHERE es.exercise_id = e.id AND es.ai_suggested = true)"
        )

    return where, params


class EnrichmentModes(BaseModel):
    skills: bool = True
    summary: bool = False
    instructions: bool = False


class EnrichmentPreviewBody(BaseModel):
    exercise_ids: List[int] = Field(..., min_length=1, max_length=MAX_PREVIEW_BATCH_EXERCISES)
    modes: EnrichmentModes = Field(default_factory=EnrichmentModes)
    merge_mode: SkillMergeMode = "replace_all"

    @field_validator("merge_mode")
    @classmethod
    def _merge_mode_ok(cls, v: str) -> str:
        if v not in SKILL_MERGE_MODES:
            raise ValueError("merge_mode: additive, replace_ai_only oder replace_all")
        return v


class EnrichmentAnalyzeBody(BaseModel):
    exercise_ids: List[int] = Field(..., min_length=1, max_length=_MAX_ANALYZE_IDS)
    modes: EnrichmentModes = Field(default_factory=EnrichmentModes)


class EnrichmentApplyItem(BaseModel):
    exercise_id: int = Field(..., ge=1)
    merged_skills: List[Dict[str, Any]] = Field(default_factory=list)
    summary: Optional[str] = None
    instruction_fields: Optional[Dict[str, Any]] = None


class EnrichmentApplyBody(BaseModel):
    items: List[EnrichmentApplyItem] = Field(..., min_length=1, max_length=MAX_BATCH_EXERCISES)
    modes: EnrichmentModes = Field(default_factory=EnrichmentModes)
    merge_mode: SkillMergeMode = "replace_all"
    set_status: Optional[str] = DEFAULT_SET_STATUS

    @field_validator("merge_mode")
    @classmethod
    def _merge_mode_ok(cls, v: str) -> str:
        if v not in SKILL_MERGE_MODES:
            raise ValueError("merge_mode: additive, replace_ai_only oder replace_all")
        return v

    @field_validator("set_status")
    @classmethod
    def _status_ok(cls, v: Optional[str]) -> Optional[str]:
        if v is None:
            return None
        s = str(v).strip().lower()
        if s == "approved":
            raise ValueError("Automatisches Freigeben (approved) ist nicht erlaubt")
        if s not in _VALID_STATUS_FILTER:
            raise ValueError("Ungültiger Ziel-Status")
        return s


@router.get("/api/admin/exercise-enrichment/candidates")
def list_enrichment_candidates(
    session: dict = Depends(require_auth),
    status: str = Query(default="draft"),
    visibility: Optional[str] = Query(default="private"),
    focus_area_id: Optional[int] = Query(default=None, ge=1),
    without_skills: bool = Query(default=False),
    with_ai_suggested_skills: bool = Query(default=False),
    search: Optional[str] = Query(default=None, max_length=200),
    limit: int = Query(default=25, ge=1, le=_MAX_CANDIDATES_LIMIT),
    offset: int = Query(default=0, ge=0),
):
    """Paginierte Kandidatenliste für Superadmin-Anreicherung."""
    _require_superadmin(session)

    where, params = _build_candidates_where(
        status=status,
        visibility=visibility,
        focus_area_id=focus_area_id,
        without_skills=without_skills,
        with_ai_suggested_skills=with_ai_suggested_skills,
    )

    qtext = (search or "").strip()
    if qtext:
        where.append("e.search_vector @@ plainto_tsquery('german', %s)")
        params.append(qtext)

    where_sql = " AND ".join(where)

    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute(f"SELECT COUNT(*) AS c FROM exercises e WHERE {where_sql}", tuple(params))
        count_row = cur.fetchone()
        total = int(count_row["c"] if isinstance(count_row, dict) else count_row[0])

        cur.execute(
            f"""
            SELECT e.id, e.title, e.status, e.visibility, e.summary, e.updated_at,
                   (
                     SELECT fa.name FROM exercise_focus_areas efa
                     JOIN focus_areas fa ON fa.id = efa.focus_area_id
                     WHERE efa.exercise_id = e.id
                     ORDER BY efa.is_primary DESC NULLS LAST, fa.name ASC
                     LIMIT 1
                   ) AS primary_focus_name,
                   (
                     SELECT COUNT(*)::int FROM exercise_skills es WHERE es.exercise_id = e.id
                   ) AS skill_count,
                   (
                     SELECT COUNT(*)::int FROM exercise_skills es
                     WHERE es.exercise_id = e.id AND es.ai_suggested = true
                   ) AS ai_suggested_skill_count
            FROM exercises e
            WHERE {where_sql}
            ORDER BY e.updated_at DESC, e.id DESC
            LIMIT %s OFFSET %s
            """,
            tuple(params + [limit, offset]),
        )
        rows = [r2d(r) for r in cur.fetchall()]

    return {
        "items": rows,
        "total": total,
        "limit": limit,
        "offset": offset,
    }


@router.get("/api/admin/exercise-enrichment/candidate-ids")
def list_enrichment_candidate_ids(
    session: dict = Depends(require_auth),
    status: str = Query(default="draft"),
    visibility: Optional[str] = Query(default="private"),
    focus_area_id: Optional[int] = Query(default=None, ge=1),
    without_skills: bool = Query(default=False),
    with_ai_suggested_skills: bool = Query(default=False),
    search: Optional[str] = Query(default=None, max_length=200),
):
    """Alle IDs zum aktuellen Filter (für „Alle auswählen“) — ohne Pagination-Obergrenze."""
    _require_superadmin(session)

    where, params = _build_candidates_where(
        status=status,
        visibility=visibility,
        focus_area_id=focus_area_id,
        without_skills=without_skills,
        with_ai_suggested_skills=with_ai_suggested_skills,
    )

    qtext = (search or "").strip()
    if qtext:
        where.append("e.search_vector @@ plainto_tsquery('german', %s)")
        params.append(qtext)

    where_sql = " AND ".join(where)

    with get_db() as conn:
        cur = get_cursor(conn)
        cur.execute(
            f"SELECT e.id FROM exercises e WHERE {where_sql} ORDER BY e.updated_at DESC, e.id DESC",
            tuple(params),
        )
        ids = [int(r["id"] if isinstance(r, dict) else r[0]) for r in cur.fetchall()]

    return {"ids": ids, "total": len(ids)}


@router.post("/api/admin/exercise-enrichment/analyze")
def analyze_enrichment(body: EnrichmentAnalyzeBody, session: dict = Depends(require_auth)):
    """Kosten-/Umfangsanalyse vor dem Batch-Lauf (explizite Nutzerbestätigung)."""
    _require_superadmin(session)

    ids = _normalize_id_list(body.exercise_ids, max_items=_MAX_ANALYZE_IDS)
    if not ids:
        raise HTTPException(status_code=400, detail="Keine gültigen Übungs-IDs")

    if not body.modes.skills and not body.modes.summary and not body.modes.instructions:
        raise HTTPException(
            status_code=400,
            detail="Mindestens ein Modus (skills, summary oder instructions) aktivieren",
        )

    est = estimate_llm_calls(
        exercise_count=len(ids),
        want_skills=body.modes.skills,
        want_summary=body.modes.summary,
        want_instructions=body.modes.instructions,
    )

    return {
        "exercise_count": len(ids),
        "estimated_llm_calls": est,
        "modes": body.modes.model_dump(),
        "warning": (
            f"Batch mit {len(ids)} Übungen und ca. {est['total']} LLM-Aufrufen — Kosten beachten."
            if len(ids) >= 25 or est["total"] >= 50
            else None
        ),
    }


def _preview_one_exercise(
    ex_id: int,
    *,
    want_skills: bool,
    want_summary: bool,
    want_instructions: bool,
    merge_mode: SkillMergeMode,
) -> Dict[str, Any]:
    """Einzel-Preview mit eigener DB-Connection (Thread-Pool)."""
    try:
        with get_db() as conn:
            cur = get_cursor(conn)
            row = preview_exercise_enrichment(
                cur,
                ex_id,
                want_skills=want_skills,
                want_summary=want_summary,
                want_instructions=want_instructions,
                merge_mode=merge_mode,
            )
        return row
    except HTTPException as he:
        d = he.detail
        return {"exercise_id": ex_id, "ok": False, "error": d if isinstance(d, str) else str(d)}
    except Exception as exc:  # pragma: no cover
        return {"exercise_id": ex_id, "ok": False, "error": str(exc)}


@router.post("/api/admin/exercise-enrichment/preview")
def preview_enrichment(body: EnrichmentPreviewBody, session: dict = Depends(require_auth)):
    """Dry-Run: KI-Vorschläge laden, nichts speichern (max. 3 Übungen/Request, parallel)."""
    _require_superadmin(session)

    ids = _normalize_id_list(body.exercise_ids, max_items=MAX_PREVIEW_BATCH_EXERCISES)
    if not ids:
        raise HTTPException(status_code=400, detail="Keine gültigen Übungs-IDs")

    modes = body.modes
    if not modes.skills and not modes.summary and not modes.instructions:
        raise HTTPException(
            status_code=400,
            detail="Mindestens ein Modus (skills, summary oder instructions) aktivieren",
        )

    results: List[Dict[str, Any]] = []
    errors: List[Dict[str, Any]] = []

    workers = min(_PREVIEW_MAX_WORKERS, len(ids))
    with ThreadPoolExecutor(max_workers=workers) as pool:
        futures = [
            pool.submit(
                _preview_one_exercise,
                ex_id,
                want_skills=modes.skills,
                want_summary=modes.summary,
                want_instructions=modes.instructions,
                merge_mode=body.merge_mode,
            )
            for ex_id in ids
        ]
        for fut in as_completed(futures):
            row = fut.result()
            if row.get("ok"):
                results.append(row)
            else:
                errors.append(row)

    results.sort(key=lambda r: int(r.get("exercise_id") or 0))
    errors.sort(key=lambda r: int(r.get("exercise_id") or 0))

    est = estimate_llm_calls(
        exercise_count=len(ids),
        want_skills=modes.skills,
        want_summary=modes.summary,
        want_instructions=modes.instructions,
    )

    return {
        "results": results,
        "errors": errors,
        "processed": len(ids),
        "ok_count": len(results),
        "error_count": len(errors),
        "estimated_llm_calls": est,
        "merge_mode": body.merge_mode,
        "modes": modes.model_dump(),
    }


@router.post("/api/admin/exercise-enrichment/apply")
def apply_enrichment(body: EnrichmentApplyBody, session: dict = Depends(require_auth)):
    """Vorschläge anwenden und optional Status setzen (Default: in_review)."""
    _require_superadmin(session)

    if not body.items:
        raise HTTPException(status_code=400, detail="Keine Items")

    modes = body.modes
    if not modes.skills and not modes.summary and not modes.instructions:
        raise HTTPException(status_code=400, detail="Kein Anwendungsmodus aktiv")

    applied: List[Dict[str, Any]] = []
    failed: List[Dict[str, Any]] = []

    with get_db() as conn:
        cur = get_cursor(conn)
        for item in body.items:
            ex_id = int(item.exercise_id)
            try:
                row = apply_exercise_enrichment(
                    cur,
                    ex_id,
                    merged_skills=item.merged_skills,
                    merge_mode=body.merge_mode,
                    set_status=body.set_status,
                    apply_skills=modes.skills,
                    summary_text=item.summary,
                    apply_summary=modes.summary,
                    instruction_fields=item.instruction_fields,
                    apply_instructions=modes.instructions,
                )
                if row.get("ok"):
                    applied.append(row)
                else:
                    failed.append(row)
            except HTTPException as he:
                d = he.detail
                failed.append({"exercise_id": ex_id, "ok": False, "error": d if isinstance(d, str) else str(d)})
            except Exception as exc:  # pragma: no cover
                failed.append({"exercise_id": ex_id, "ok": False, "error": str(exc)})
        conn.commit()

    return {
        "applied": applied,
        "failed": failed,
        "applied_count": len(applied),
        "failed_count": len(failed),
        "set_status": body.set_status,
        "merge_mode": body.merge_mode,
        "modes": modes.model_dump(),
    }