"""
KI-Vorschlaege fuer Uebungsformular: Laedt Prompts aus ai_prompts, ruft OpenRouter auf.
Keine persistente Aenderung an exercises — nur Response-DTO fuer das Frontend.
"""
from __future__ import annotations

import json
import re
from typing import Any, Dict, List, Optional, Tuple

from fastapi import HTTPException

from openrouter_chat import OpenRouterError, normalize_openrouter_env, openrouter_chat_completion

_CANONICAL_SKILL_LEVELS = frozenset({"basis", "grundlagen", "aufbau", "fortgeschritten", "optimierung"})
_LEGACY_SKILL_LEVEL_SLUG = {
    "einsteiger": "basis",
    "experte": "optimierung",
    "1": "basis",
    "2": "grundlagen",
    "3": "aufbau",
    "4": "fortgeschritten",
    "5": "optimierung",
}
_ALLOWED_SKILL_INTENSITY = frozenset({"niedrig", "mittel", "hoch"})


def _normalize_exercise_skill_level(value) -> Optional[str]:
    if value is None:
        return None
    s = str(value).strip().lower()
    if not s:
        return None
    if s in _CANONICAL_SKILL_LEVELS:
        return s
    return _LEGACY_SKILL_LEVEL_SLUG.get(s)


def _normalize_exercise_skill_intensity(value) -> str:
    if value is None:
        return "mittel"
    key = str(value).strip().lower()
    if key in ("low",):
        return "niedrig"
    if key in ("medium",):
        return "mittel"
    if key in ("high",):
        return "hoch"
    if key in _ALLOWED_SKILL_INTENSITY:
        return key
    return "mittel"

_TAG_RE = re.compile(r"<[^>]+>", re.IGNORECASE)

_MAX_PLAIN_FIELD = 28_000
_MAX_SKILLS_CATALOG_LINES = 240
_MAX_SUMMARY_CHARS = 220


def strip_html_to_plain(html: Optional[str], *, max_len: int = _MAX_PLAIN_FIELD) -> str:
    if not html:
        return ""
    t = _TAG_RE.sub(" ", str(html))
    t = re.sub(r"\s+", " ", t).strip()
    if len(t) > max_len:
        t = t[: max_len - 1].rstrip() + "…"
    return t


def _load_prompt_row(cur, slug: str) -> Optional[Dict[str, Any]]:
    cur.execute(
        """
        SELECT slug, display_name, template, output_format, active
        FROM ai_prompts
        WHERE slug = %s
        """,
        (slug,),
    )
    row = cur.fetchone()
    if not row:
        return None
    d = dict(row)
    if not d.get("active", True):
        return None
    return d


def _render_template(template: str, ctx: Dict[str, str]) -> str:
    out = template or ""
    for key, val in ctx.items():
        placeholder = "{{" + key + "}}"
        out = out.replace(placeholder, val if val is not None else "")
    return out


def _build_skills_catalog_block(cur) -> str:
    cur.execute(
        """
        SELECT s.id, s.name, s.category, s.description, s.karate_relevance, s.relevance_level,
               sc.name AS subcategory_name
        FROM skills s
        LEFT JOIN skill_categories sc ON s.category_id = sc.id
        WHERE (s.status IS NULL OR s.status = 'active')
        ORDER BY s.importance DESC NULLS LAST, s.name
        LIMIT %s
        """,
        (_MAX_SKILLS_CATALOG_LINES,),
    )
    lines: List[str] = []
    for r in cur.fetchall():
        rid = int(r["id"])
        nm = (r.get("name") or "").strip() or f"Skill #{rid}"
        cat = (r.get("category") or "").strip()
        sub = (r.get("subcategory_name") or "").strip()
        dsc = strip_html_to_plain(r.get("description"), max_len=320)
        kr = strip_html_to_plain(r.get("karate_relevance"), max_len=200)
        rel = r.get("relevance_level")
        rel_s = ""
        if rel is not None:
            rel_s = str(rel)

        cats = " / ".join(x for x in (cat, sub) if x)

        blob = (
            f"- id={rid} | name={nm} | kategorie={cats or '-'}"
            f" | beschreibung={dsc or '-'} | karate_relevanz={kr or '-'}"
            f" | relevanz_stufe={rel_s or '-'}"
        )
        lines.append(blob)
    return "\n".join(lines) if lines else "(keine aktiven Skills im Katalog)"


def _extract_json_array(text: str) -> Any:
    s = text.strip()
    if s.startswith("```"):
        s = re.sub(r"^```[a-zA-Z0-9]*\s*", "", s)
        if s.endswith("```"):
            s = s[:-3].strip()
    # array whole string
    if s.startswith("["):
        end = s.rfind("]")
        if end > 0:
            s = s[: end + 1]
            return json.loads(s)
    # object wrapping array
    if s.startswith("{"):
        obj = json.loads(s)
        if isinstance(obj, dict):
            for k in ("skills", "items", "data"):
                v = obj.get(k)
                if isinstance(v, list):
                    return v
        raise ValueError("JSON-Objekt ohne Skills-Liste")
    return json.loads(s)


def _sanitize_skill_entries(cur, rows: Any) -> List[Dict[str, Any]]:
    if not isinstance(rows, list):
        return []
    out: List[Dict[str, Any]] = []
    for raw in rows:
        if not isinstance(raw, dict):
            continue
        sid = raw.get("skill_id")
        try:
            skill_id = int(sid)
        except (TypeError, ValueError):
            continue
        cur.execute(
            """
            SELECT s.id, s.name, s.category,
                   sc.name AS subcategory_name
            FROM skills s
            LEFT JOIN skill_categories sc ON s.category_id = sc.id
            WHERE s.id = %s AND (s.status IS NULL OR s.status = 'active')
            """,
            (skill_id,),
        )
        sk = cur.fetchone()
        if not sk:
            continue

        req = _normalize_exercise_skill_level(raw.get("required_level")) or "grundlagen"
        tgt = _normalize_exercise_skill_level(raw.get("target_level")) or req
        if req not in _CANONICAL_SKILL_LEVELS:
            req = _LEGACY_SKILL_LEVEL_SLUG.get(str(raw.get("required_level") or "").strip().lower(), "grundlagen")
            if req not in _CANONICAL_SKILL_LEVELS:
                req = "grundlagen"
        if tgt not in _CANONICAL_SKILL_LEVELS:
            tgt = _LEGACY_SKILL_LEVEL_SLUG.get(str(raw.get("target_level") or "").strip().lower(), req)
            if tgt not in _CANONICAL_SKILL_LEVELS:
                tgt = req

        inten = _normalize_exercise_skill_intensity(raw.get("intensity"))

        is_primary = bool(raw.get("is_primary")) if raw.get("is_primary") is not None else len(out) == 0

        cat = (sk.get("category") or "").strip()
        sub = (sk.get("subcategory_name") or "").strip()
        skill_category = " / ".join(x for x in (cat, sub) if x) or (cat or None)

        conf = raw.get("confidence")
        try:
            conf_f = float(conf) if conf is not None else None
        except (TypeError, ValueError):
            conf_f = None

        item: Dict[str, Any] = {
            "skill_id": skill_id,
            "skill_name": (sk.get("name") or "").strip() or f"Skill #{skill_id}",
            "required_level": req,
            "target_level": tgt,
            "intensity": inten,
            "is_primary": is_primary,
        }
        if skill_category:
            item["skill_category"] = skill_category
        if conf_f is not None:
            item["confidence"] = conf_f
        out.append(item)

    # max 5
    return out[:5]


def _require_openrouter() -> Tuple[str, str]:
    key, model = normalize_openrouter_env()
    if not key:
        raise HTTPException(
            status_code=503,
            detail="KI nicht konfiguriert (OPENROUTER_API_KEY fehlt).",
        )
    return key, model


def run_exercise_ai_suggestion(
    cur,
    *,
    title: Optional[str],
    goal: Optional[str],
    execution: Optional[str],
    focus_area_hint: Optional[str],
    want_summary: bool,
    want_skills: bool,
) -> Dict[str, Any]:
    key, model = _require_openrouter()

    g_plain = strip_html_to_plain(goal)
    e_plain = strip_html_to_plain(execution)
    if not (g_plain.strip() or e_plain.strip()):
        raise HTTPException(
            status_code=400,
            detail="Mindestens Ziel oder Durchfuehrung muss Inhalt liefern (nach Entfernen von leerem HTML).",
        )

    t_title = (title or "").strip()
    focus = (focus_area_hint or "").strip()

    result: Dict[str, Any] = {"model": model}

    if want_summary:
        prow = _load_prompt_row(cur, "exercise_summary")
        if not prow:
            raise HTTPException(status_code=503, detail="Prompt exercise_summary nicht aktiv oder fehlt in DB.")
        ctx = {
            "exercise_title": t_title or "-",
            "exercise_focus_area": focus or "-",
            "exercise_goal": g_plain or "-",
            "exercise_execution": e_plain or "-",
        }
        prompt = _render_template(str(prow["template"]), ctx)
        try:
            raw = openrouter_chat_completion(api_key=key, model=model, user_content=prompt)
        except OpenRouterError as e:
            raise HTTPException(status_code=502, detail=f"OpenRouter: {e}") from e
        text = (raw or "").strip()
        if len(text) > _MAX_SUMMARY_CHARS:
            text = text[: _MAX_SUMMARY_CHARS - 1].rstrip() + "…"
        result["summary"] = {"text": text, "ai_generated": True, "model": model}

    if want_skills:
        srow = _load_prompt_row(cur, "exercise_skill_suggestions")
        if not srow:
            raise HTTPException(
                status_code=503,
                detail="Prompt exercise_skill_suggestions nicht aktiv oder fehlt in DB.",
            )
        catalog = _build_skills_catalog_block(cur)
        ctx = {
            "exercise_title": t_title or "-",
            "exercise_focus_area": focus or "-",
            "exercise_goal": g_plain or "-",
            "exercise_execution": e_plain or "-",
            "skills_catalog": catalog,
        }
        prompt = _render_template(str(srow["template"]), ctx)
        sys_hint = (
            "Du antwortest nur mit validem JSON (Array). Keine Kommentare, keine Erklaerungen ausserhalb des JSON."
        )
        try:
            raw = openrouter_chat_completion(
                api_key=key,
                model=model,
                user_content=prompt,
                system_content=sys_hint,
                temperature=0.15,
            )
        except OpenRouterError as e:
            raise HTTPException(status_code=502, detail=f"OpenRouter: {e}") from e
        try:
            parsed = _extract_json_array(raw)
        except (json.JSONDecodeError, ValueError) as e:
            raise HTTPException(
                status_code=502,
                detail="KI lieferte kein verwertbares JSON fuer Skills.",
            ) from e
        skills = _sanitize_skill_entries(cur, parsed)
        result["skills"] = skills

    return result