"""Consumables: repeatable, expiring boosts - a recurring coin sink.

Unlike SHOP items (permanent, bought once), consumables are bought over and
over. Buying either activates a timed buff (stored in user["active_buffs"] as
{kind: expiry_iso}) or applies an instant effect, and the coins are destroyed -
so this keeps the shop relevant, and the economy draining, after a player has
maxed out permanent gear.

Effect hooks live where the effect belongs:
  - "earn" buff  -> income.do_work / do_beg / do_crime (via earn_mult)
  - "exp"  buff  -> levels.award_exp             (via exp_buff_mult)
  - instant kohv -> handled entirely here (wipes cooldown timestamps)
"""

from __future__ import annotations

from datetime import timedelta
from typing import TypedDict

import strings

from ..pb_client import DatabaseError
from ..emoji import EMOJI as E
from .store import _commit, _locked_by, _now, _parse_dt, _txn, get_user

__all__ = [
    "Consumable",
    "CONSUMABLES",
    "INSTANT_RESET_COMMANDS",
    "active_buffs",
    "buff_remaining",
    "earn_mult",
    "exp_buff_mult",
    "grant_buff",
    "do_buy_consumable",
]


class Consumable(TypedDict):
    name: str
    emoji: str
    cost: int
    description: str
    kind: str          # active_buffs key ("earn"/"exp"), or "instant"
    duration_min: int  # buff lifetime in minutes (0 for instant effects)


CONSUMABLES: dict[str, Consumable] = {
    "energy_xl": {
        "name": "Energiajook XL",
        "emoji": E["TipiBULL"],
        "cost": 500,
        "description": strings.CONSUMABLE_DESCRIPTIONS["energy_xl"],
        "kind": "earn",
        "duration_min": 60,
    },
    "xp_potion": {
        "name": "XP jook",
        "emoji": "✨",
        "cost": 500,
        "description": strings.CONSUMABLE_DESCRIPTIONS["xp_potion"],
        "kind": "exp",
        "duration_min": 60,
    },
    "kohv": {
        "name": "Kohv",
        "emoji": "☕",
        "cost": 300,
        "description": strings.CONSUMABLE_DESCRIPTIONS["kohv"],
        "kind": "instant",
        "duration_min": 0,
    },
}

# Multiplier granted while a buff of each kind is active.
_BUFF_MULT: dict[str, float] = {"earn": 2.0, "exp": 2.0}

# Cooldown timestamps an instant "kohv" clears.
_COOLDOWN_FIELDS = ("last_work", "last_beg", "last_crime", "last_rob", "last_fish")

# The slash-command names whose cooldowns an instant "kohv" clears. The Discord
# layer uses these to cancel any pending reminder DMs, since the cooldowns they
# were scheduled for no longer exist.
INSTANT_RESET_COMMANDS = tuple(f.removeprefix("last_") for f in _COOLDOWN_FIELDS)


# ---------------------------------------------------------------------------
# Buff inspection helpers (pure - safe to call while holding a user lock)
# ---------------------------------------------------------------------------
def active_buffs(user) -> dict[str, str]:
    """Return {kind: expiry_iso} for buffs that have not expired yet."""
    buffs = user.get("active_buffs") or {}
    now = _now()
    out: dict[str, str] = {}
    for kind, expiry in buffs.items():
        dt = _parse_dt(expiry)
        if dt is not None and dt > now:
            out[kind] = expiry
    return out


def buff_remaining(user, kind: str) -> timedelta | None:
    """Remaining time on a buff kind, or None if it is inactive."""
    expiry = active_buffs(user).get(kind)
    if expiry is None:
        return None
    return _parse_dt(expiry) - _now()


def earn_mult(user) -> float:
    """Earnings multiplier from an active 'earn' buff (1.0 if none)."""
    return _BUFF_MULT["earn"] if "earn" in active_buffs(user) else 1.0


def exp_buff_mult(user) -> float:
    """EXP multiplier from an active 'exp' buff (1.0 if none)."""
    return _BUFF_MULT["exp"] if "exp" in active_buffs(user) else 1.0


def grant_buff(user, kind: str, duration_min: int) -> bool:
    """Add/extend a timed buff of `kind` on `user` in place. Stacks: extends from
    the current expiry if still active, else starts now. Returns True if it
    extended an existing buff. Pure - safe under a user lock (caller commits)."""
    buffs = dict(user.get("active_buffs") or {})
    current = _parse_dt(buffs.get(kind))
    extended = current is not None and current > _now()
    start = current if extended else _now()
    buffs[kind] = (start + timedelta(minutes=duration_min)).isoformat()
    user["active_buffs"] = buffs
    return extended


# ---------------------------------------------------------------------------
# /consumables purchase
# ---------------------------------------------------------------------------
@_locked_by(0)
async def do_buy_consumable(user_id: int, cons_id: str) -> dict:
    if cons_id not in CONSUMABLES:
        return {"ok": False, "reason": "not_found"}
    try:
        user = await get_user(user_id)
    except DatabaseError:
        return {"ok": False, "reason": "db_error"}
    if user.get("eco_banned"):
        return {"ok": False, "reason": "banned"}

    cons = CONSUMABLES[cons_id]
    if user["balance"] < cons["cost"]:
        return {"ok": False, "reason": "insufficient", "need": cons["cost"] - user["balance"]}

    user["balance"] -= cons["cost"]

    extended = False
    if cons["kind"] == "instant":
        for field in _COOLDOWN_FIELDS:
            user[field] = None
    else:
        extended = grant_buff(user, cons["kind"], cons["duration_min"])

    await _commit(user_id, user)
    _txn("BUY_CONSUMABLE", user=user_id, item=cons_id, cost=f"-{cons['cost']}", bal=user["balance"])

    return {
        "ok": True,
        "consumable": cons,
        "balance": user["balance"],
        "instant": cons["kind"] == "instant",
        "extended": extended,
        "remaining": None if cons["kind"] == "instant" else buff_remaining(user, cons["kind"]),
    }