import asyncio
import math
import random
from time import time
from types import SimpleNamespace
from typing import Dict, List, Literal, Tuple

from varco_arena_core.prompts import ComparisonPromptBase

from .match import Match


async def limited_coro(coro, semaphore):
    async with semaphore:
        return await coro


def log2_power_of_two(n):
    # First, let's make sure n is indeed a power of 2
    if n & (n - 1) != 0 or n == 0:
        raise ValueError("n must be a positive power of 2")

    exponent = 0
    while n > 1:
        n >>= 1  # Right shift is like dividing by 2, but faster
        exponent += 1
    return exponent


class Tournament:
    """
    Perform single elimination tournament of model outputs
    """

    def __init__(self, participants, evaluation_model):
        self.participants = participants
        self.evaluation_model = evaluation_model

    async def async_run(
        self,
        prompt_obj: ComparisonPromptBase = None,
        semaphore: asyncio.Semaphore = None,
    ) -> List[Dict]:
        random.shuffle(self.participants)

        result = []
        next_higher_power_of_two = int(
            math.pow(2, math.ceil(math.log2(len(self.participants))))
        )
        winners_number_of_byes = next_higher_power_of_two - len(
            self.participants
        )  # 부전승
        current_round_participant = self.participants + [None] * winners_number_of_byes

        async def get_match_results(
            a,
            b,
            match_order,
            cur_round,  # position_swap=False,
            depth: int = None,
        ) -> Tuple[SimpleNamespace, List[Dict]]:
            if a is None and b is None:
                next_round_participant = None
                result = None
            elif a is not None and b is None:
                next_round_participant = a
                result = None
            elif a is None and b is not None:
                next_round_participant = b
                result = None
            else:
                match = Match(A=a, B=b, eval_model=self.evaluation_model)
                if self.evaluation_model == "debug":
                    winner, match_result = await match.async_dbg_eval()
                else:
                    winner, match_result = await match.async_comp_eval(
                        comp_prompt=prompt_obj,
                    )
                if winner is None:
                    next_round_participant = None
                    result = None
                else:
                    if winner == "A":
                        next_round_participant = a
                    else:
                        next_round_participant = b
                    now_time = time()
                    # A vs B, B vs A
                    result = [
                        {  # 여기서 *_a, *_b 는 prompt내의 position에 관한 것이다. Match.A, Match.B 가 아니다.
                            "task": a.task,  # participant_pair[1].task
                            "model_a": a.model_id,
                            "model_b": b.model_id,
                            "winner": "A"
                            if match_result[0]["A"] > match_result[0]["B"]
                            else "B",
                            "prob_a": match_result[0]["A"],
                            "prob_b": match_result[0]["B"],
                            "evaluation_model": self.evaluation_model,
                            "instruction": a.instruction,  # participant_pair[1].instruction,
                            "source": a.source,  # participant_pair[1].source,
                            "generated_a": a.generated,
                            "generated_b": b.generated,
                            "tournament_idx": a.tournament_idx,
                            "round": cur_round,
                            "depth": depth,
                            "match_order_in_round": match_order,
                            "tstamp": now_time,
                            "api_call_kwargs": match_result[0]["api_call_kwargs"],
                            "actual_response_text": match_result[0]["actual_response_text"],
                        },
                    ]
                    try:
                        result[0]["source_language"] = a.source_language
                        result[0]["target_language"] = a.target_language
                    except:
                        pass

            # next_round_participant = SimpleNamespace(A) if winner=="A" from Match.async_comp_eval()
            return next_round_participant, result

        while len(current_round_participant) > 1:
            half_length = int(len(current_round_participant) / 2)
            first = current_round_participant[:half_length]
            last = current_round_participant[half_length:]
            last.reverse()

            # human-readable rounds
            # key name and value format is just right for web view. do not remove or modify
            if len(current_round_participant) == 2:
                cur_round = "final"
            elif len(current_round_participant) == 4:
                cur_round = "semi-final"
            elif len(current_round_participant) == 8:
                cur_round = "quarter-final"
            else:
                cur_round = f"round-{len(current_round_participant)}"

            # later used for bracket re-building
            cur_depth = log2_power_of_two(len(current_round_participant)) - 1

            match_order = 0
            match_jobs = []
            for participant_0, participant_1, i in zip(first, last, range(len(last))):
                participant_pair = (participant_0, participant_1)

                if i % 2 == 1:
                    participant_pair = (participant_1, participant_0)

                match_jobs.append(
                    limited_coro(
                        get_match_results(
                            participant_pair[0],
                            participant_pair[1],
                            match_order,
                            cur_round,
                            depth=cur_depth,
                        ),
                        semaphore,
                    )
                    # get_match_results(participant_pair[0], participant_pair[1], match_order, cur_round)
                )
                match_order += 1
            pairs_of_winner_and_result = await asyncio.gather(*match_jobs)
            next_round_participant, current_round_result = map(
                list, zip(*pairs_of_winner_and_result)
            )

            current_round_result = [
                _result
                for result_pair in current_round_result
                if result_pair is not None
                for _result in result_pair
            ]
            result.extend(current_round_result)

            current_round_participant = next_round_participant

        return result