"""
ShufflerController — mirrors the JS makeShuffler() no-repeat logic.

The seen-list for each named pool is kept inside a dict that lives in
gr.BrowserState (localStorage).  The state dict shape:

  {
    "jam":        {"seen": ["...", ...]},
    "tt_easy":    {"seen": [...]},
    "tt_medium":  {"seen": [...]},
    "tt_hard":    {"seen": [...]},
    "imp_all":    {"seen": [...]},
    "imp_0":      {"seen": [...]},   # per-category index
    ...
    "iv_all":     {"seen": [...]},
    "iv_0":       {"seen": [...]},
    ...
  }
"""
import json
import random

from pydantic import BaseModel
from models.session_models import ShufflerState


def _serialise(item) -> str:
    if isinstance(item, str):
        return item
    if isinstance(item, BaseModel):
        return json.dumps(item.model_dump(), ensure_ascii=False, sort_keys=True)
    return json.dumps(item, ensure_ascii=False)


def next_item(pool: list, key: str, raw_state: dict) -> tuple:
    """
    Pick the next unseen item from pool.
    Returns (item, updated_raw_state).
    """
    if not pool:
        return None, raw_state

    state_dict   = raw_state.get(key, {}) if isinstance(raw_state, dict) else {}
    shuffler     = ShufflerState.model_validate(state_dict)
    seen_set     = set(shuffler.seen)

    unseen = [i for i, item in enumerate(pool) if _serialise(item) not in seen_set]
    if not unseen:
        # Full cycle complete — reset
        shuffler.seen = []
        seen_set = set()
        unseen = list(range(len(pool)))

    idx    = random.choice(unseen)
    picked = pool[idx]
    shuffler.seen.append(_serialise(picked))

    updated = dict(raw_state) if isinstance(raw_state, dict) else {}
    updated[key] = shuffler.model_dump()
    return picked, updated


def reset_key(key: str, raw_state: dict) -> dict:
    """Reset the seen list for a single key."""
    updated = dict(raw_state) if isinstance(raw_state, dict) else {}
    updated[key] = ShufflerState().model_dump()
    return updated


def imp_pool_key(cat: str, categories: list) -> str:
    if cat == "All":
        return "imp_all"
    idx = next((i for i, c in enumerate(categories) if c.category == cat), 0)
    return f"imp_{idx}"


def iv_pool_key(cat: str, categories: list) -> str:
    if cat == "All":
        return "iv_all"
    idx = next((i for i, c in enumerate(categories) if c.category == cat), 0)
    return f"iv_{idx}"