from __future__ import annotations

from dataclasses import dataclass
import json
from typing import Any, Dict, Mapping

from redis.asyncio import Redis


ARBITRAGE_LUA = r'''
local odds_json = ARGV[1]
local payload = cjson.decode(odds_json)

local grouped = {}
for _, row in ipairs(payload) do
  local market = row.market_type
  local selection = row.selection
  local odds = tonumber(row.decimal_odds)
  if market and selection and odds and odds > 0 then
    if grouped[market] == nil then
      grouped[market] = {}
    end
    if grouped[market][selection] == nil or odds > grouped[market][selection] then
      grouped[market][selection] = odds
    end
  end
end

local out = {}
for market, selections in pairs(grouped) do
  local prob_sum = 0
  local count = 0
  for _, odds in pairs(selections) do
    prob_sum = prob_sum + (1 / odds)
    count = count + 1
  end
  if count > 1 then
    out[market] = {
      has_arbitrage = (prob_sum < 1),
      implied_total_probability = prob_sum,
      edge = math.max(1 - prob_sum, 0),
      best_odds = selections,
    }
  end
end

return cjson.encode(out)
'''


@dataclass(slots=True)
class MatchState:
    """賽中 Hash 快照欄位。"""

    home_score: int
    away_score: int
    possession_home_pct: float
    possession_away_pct: float
    red_cards_home: int
    red_cards_away: int


class MatchCacheManager:
    """賽事 Redis 快取層。

    - live:{match_id}:odds 存 JSON，即時賠率
    - live:{match_id}:state 存 Hash，包含比分、控球率、紅牌數
    """

    def __init__(self, redis: Redis) -> None:
        self.redis = redis
        self._lua_sha: str | None = None

    async def _ensure_lua(self) -> str:
        if self._lua_sha is None:
            self._lua_sha = await self.redis.script_load(ARBITRAGE_LUA)
        return self._lua_sha

    async def set_match_odds(
        self,
        match_id: str,
        payload: list[dict[str, Any]],
        *,
        ttl_seconds: int = 45,
        finished: bool = False,
    ) -> None:
        key = f'live:{match_id}:odds'
        value = json.dumps(payload, ensure_ascii=False)
        ttl = 7200 if finished else ttl_seconds
        await self.redis.set(name=key, value=value, ex=ttl)

    async def get_match_odds(self, match_id: str) -> list[dict[str, Any]]:
        key = f'live:{match_id}:odds'
        raw = await self.redis.get(key)
        if not raw:
            return []
        if isinstance(raw, bytes):
            raw = raw.decode()
        return json.loads(raw)

    async def set_match_state(
        self,
        match_id: str,
        state: MatchState | Mapping[str, Any],
        *,
        ttl_seconds: int = 7200,
    ) -> None:
        key = f'live:{match_id}:state'
        mapping = {
            'home_score': state['home_score'] if isinstance(state, Mapping) else state.home_score,
            'away_score': state['away_score'] if isinstance(state, Mapping) else state.away_score,
            'possession_home_pct': state['possession_home_pct'] if isinstance(state, Mapping) else state.possession_home_pct,
            'possession_away_pct': state['possession_away_pct'] if isinstance(state, Mapping) else state.possession_away_pct,
            'red_cards_home': state['red_cards_home'] if isinstance(state, Mapping) else state.red_cards_home,
            'red_cards_away': state['red_cards_away'] if isinstance(state, Mapping) else state.red_cards_away,
        }
        await self.redis.hset(name=key, mapping=mapping)
        await self.redis.expire(key, ttl_seconds)

    async def get_match_state(self, match_id: str) -> dict[str, str] | None:
        key = f'live:{match_id}:state'
        result = await self.redis.hgetall(key)
        return {str(k): str(v) for k, v in result.items()} if result else None

    async def calculate_arbitrage_for_match(self, match_id: str) -> dict[str, Any]:
        odds = await self.get_match_odds(match_id)
        if not odds:
            return {}

        sha = await self._ensure_lua()
        result = await self.redis.evalsha(sha, 0, json.dumps(odds, ensure_ascii=False))
        if isinstance(result, bytes):
            result = result.decode()
        if isinstance(result, str):
            return json.loads(result)
        return result