"""Admin analytics: aggregate trainee results, with optional date-range filter."""
from __future__ import annotations

import datetime

from flask import Blueprint, jsonify, request

from .helpers import current_user, require_auth, require_roles

analytics_bp = Blueprint("analytics", __name__)


def _stores():
    from flask import current_app

    return {
        "sessions": current_app.extensions["session_store"],
        "groups": current_app.extensions["group_store"],
        "users": current_app.extensions["user_store"],
    }


def _parse_date(val: str):
    if not val:
        return None
    try:
        return datetime.datetime.fromisoformat(val)
    except ValueError:
        try:
            return datetime.datetime.strptime(val, "%Y-%m-%d")
        except ValueError:
            return None


@analytics_bp.get("")
@require_auth
@require_roles("admin")
def analytics():
    s = _stores()
    actor = current_user()

    # Optional date-range filter (inclusive): ?from=YYYY-MM-DD&to=YYYY-MM-DD
    d_from = _parse_date((request.args.get("from") or "").strip())
    d_to = _parse_date((request.args.get("to") or "").strip())
    if d_to:
        # include the whole "to" day
        d_to = d_to.replace(hour=23, minute=59, second=59, microsecond=999999)

    if actor.get("role") == "super_admin":
        sessions = s["sessions"].sessions.all()
        users = s["users"].list_users()
    else:
        org_id = actor.get("org_id")
        users = s["users"].list_users(org_id=org_id)
        user_ids = {u["id"] for u in users}
        sessions = [
            x for x in s["sessions"].sessions.all() if x.get("user_id") in user_ids
        ]

    if d_from or d_to:
        filtered = []
        for x in sessions:
            ts = x.get("created_at") or x.get("finished_at") or ""
            if not ts:
                continue
            try:
                dt = datetime.datetime.fromisoformat(ts)
            except ValueError:
                continue
            if d_from and dt < d_from:
                continue
            if d_to and dt > d_to:
                continue
            filtered.append(x)
        sessions = filtered

    overall = {
        "total_sessions": len(sessions),
        "wins": sum(1 for x in sessions if x.get("outcome") == "won"),
        "losses": sum(1 for x in sessions if x.get("outcome") == "lost"),
    }
    overall["close_rate"] = (
        round(overall["wins"] / overall["total_sessions"] * 100, 1)
        if overall["total_sessions"]
        else 0
    )

    # average score
    scores = [
        (x.get("debrief") or {}).get("score", 0)
        for x in sessions
        if x.get("outcome")
    ]
    overall["avg_score"] = round(sum(scores) / len(scores), 1) if scores else 0

    # hardest personas = personas with most losses (lowest avg score)
    by_persona: dict = {}
    for x in sessions:
        key = (x.get("group_id"), x.get("persona_id"), x.get("persona_name", "?"))
        if key not in by_persona:
            by_persona[key] = {"plays": 0, "losses": 0, "wins": 0, "scores": []}
        rec = by_persona[key]
        rec["plays"] += 1
        rec["scores"].append((x.get("debrief") or {}).get("score", 0))
        if x.get("outcome") == "won":
            rec["wins"] += 1
        elif x.get("outcome") == "lost":
            rec["losses"] += 1
    hardest = sorted(
        (
            {
                "persona_name": k[2],
                "plays": v["plays"],
                "wins": v["wins"],
                "losses": v["losses"],
                "avg_score": round(sum(v["scores"]) / len(v["scores"]), 1)
                if v["scores"]
                else 0,
            }
            for k, v in by_persona.items()
        ),
        key=lambda r: (r["losses"], -r["avg_score"]),
    )[:10]

    # per-user summary so the admin overview can show per-trainee results
    by_user: dict = {}
    for x in sessions:
        uid = x.get("user_id", "?")
        if uid not in by_user:
            by_user[uid] = {"sessions": 0, "wins": 0, "losses": 0}
        by_user[uid]["sessions"] += 1
        if x.get("outcome") == "won":
            by_user[uid]["wins"] += 1
        elif x.get("outcome") == "lost":
            by_user[uid]["losses"] += 1
    name_by_id = {u.get("id"): u.get("name") or u.get("username") for u in users}
    per_user = [
        {
            "user_id": uid,
            "name": name_by_id.get(uid, uid),
            **v,
        }
        for uid, v in by_user.items()
    ]

    return jsonify({
        "overall": overall,
        "trainee_count": len(users),
        "hardest_personas": hardest,
        "per_user": per_user,
    })