from dataclasses import dataclass
from enum import IntEnum, auto
from typing import List

import numpy as np
import torch

from sglang.srt.managers.router.radix_cache import RadixCache
from sglang.srt.memory_pool import ReqToTokenPool, TokenToKVPool


class ForwardMode(IntEnum):
    PREFILL = auto()
    EXTEND = auto()
    DECODE = auto()


class FinishReason(IntEnum):
    EOS_TOKEN = auto()
    LENGTH = auto()
    STOP_STR = auto()
    ABORT = auto()

    @staticmethod
    def to_str(reason):
        if reason == FinishReason.EOS_TOKEN:
            return None
        elif reason == FinishReason.LENGTH:
            return "length"
        elif reason == FinishReason.STOP_STR:
            return "stop"
        elif reason == FinishReason.ABORT:
            return "abort"
        else:
            return None


class Req:
    def __init__(self, rid, origin_input_text, origin_input_ids):
        self.rid = rid
        self.origin_input_text = origin_input_text
        self.origin_input_ids = origin_input_ids
        self.origin_input_ids_unpadded = origin_input_ids  # before image padding
        self.prev_output_str = ""
        self.prev_output_ids = []
        self.output_ids = []
        self.input_ids = None  # input_ids = origin_input_ids + prev_output_ids

        # The number of decoded tokens for token usage report. Note that
        # this does not include the jump forward tokens.
        self.completion_tokens_wo_jump_forward = 0

        # For vision input
        self.pixel_values = None
        self.image_size = None
        self.image_offset = 0
        self.pad_value = None

        # Sampling parameters
        self.sampling_params = None
        self.stream = False

        # Check finish
        self.tokenizer = None
        self.finished = False
        self.finish_reason = None
        self.hit_stop_str = None

        self.extend_input_len = 0
        self.prefix_indices = []
        self.last_node = None

        # Logprobs
        self.return_logprob = False
        self.logprob_start_len = 0
        self.top_logprobs_num = 0
        self.normalized_prompt_logprob = None
        self.prefill_token_logprobs = None
        self.decode_token_logprobs = []
        self.prefill_top_logprobs = None
        self.decode_top_logprobs = []
        # The tokens is prefilled but need to be considered as decode tokens
        # and should be updated for the decode logprobs
        self.last_update_decode_tokens = 0

        # Constrained decoding
        self.regex_fsm = None
        self.regex_fsm_state = 0
        self.jump_forward_map = None

    def partial_decode(self, ids):
        first_token = self.tokenizer.convert_ids_to_tokens(ids[0])
        first_token = (
            first_token.decode() if isinstance(first_token, bytes) else first_token
        )
        return (" " if first_token.startswith("▁") else "") + self.tokenizer.decode(ids)

    def max_new_tokens(self):
        return self.sampling_params.max_new_tokens

    def check_finished(self):
        if self.finished:
            return

        if (
            len(self.prev_output_ids) + len(self.output_ids)
            >= self.sampling_params.max_new_tokens
        ):
            self.finished = True
            self.finish_reason = FinishReason.LENGTH
            return

        if (
            self.output_ids[-1] == self.tokenizer.eos_token_id
            and self.sampling_params.ignore_eos == False
        ):
            self.finished = True
            self.finish_reason = FinishReason.EOS_TOKEN
            return

        if len(self.sampling_params.stop_strs) > 0:
            tail_str = self.tokenizer.decode(
                self.output_ids[-(self.sampling_params.stop_str_max_len + 1) :]
            )

            for stop_str in self.sampling_params.stop_strs:
                # FIXME: (minor) try incremental match in prev_output_str
                if stop_str in tail_str or stop_str in self.prev_output_str:
                    self.finished = True
                    self.finish_reason = FinishReason.STOP_STR
                    self.hit_stop_str = stop_str
                    return

    def jump_forward_and_retokenize(self, jump_forward_str, next_state):
        # FIXME: This logic does not really solve the problem of determining whether
        # there should be a leading space.
        cur_output_str = self.partial_decode(self.output_ids)

        # TODO(lsyin): apply re-tokenize only for decode tokens so that we do not need origin_input_text anymore
        if self.origin_input_text is None:
            # Recovering text can only use unpadded ids
            self.origin_input_text = self.tokenizer.decode(
                self.origin_input_ids_unpadded
            )

        all_text = (
            self.origin_input_text
            + self.prev_output_str
            + cur_output_str
            + jump_forward_str
        )
        all_ids = self.tokenizer.encode(all_text)
        prompt_tokens = len(self.origin_input_ids_unpadded)
        self.origin_input_ids = all_ids[:prompt_tokens]
        self.origin_input_ids_unpadded = self.origin_input_ids
        # NOTE: the output ids may not strictly correspond to the output text
        old_prev_output_ids = self.prev_output_ids
        self.prev_output_ids = all_ids[prompt_tokens:]
        self.prev_output_str = self.prev_output_str + cur_output_str + jump_forward_str
        self.output_ids = []

        self.regex_fsm_state = next_state

        if self.return_logprob:
            # For fast-forward part's logprobs
            k = 0
            for i, old_id in enumerate(old_prev_output_ids):
                if old_id == self.prev_output_ids[i]:
                    k = k + 1
                else:
                    break
            self.decode_token_logprobs = self.decode_token_logprobs[:k]
            self.decode_top_logprobs = self.decode_top_logprobs[:k]
            self.logprob_start_len = prompt_tokens + k
            self.last_update_decode_tokens = len(self.prev_output_ids) - k

        # print("=" * 100)
        # print(f"Catch jump forward:\n{jump_forward_str}")
        # print(self.tokenizer.convert_ids_to_tokens(self.input_ids))
        # print(self.tokenizer.convert_ids_to_tokens(new_input_ids))

        # print(f"Output and jump forward str:\n{self.output_and_jump_forward_str}")
        # print("*" * 100)

    def __repr__(self):
        return f"rid(n={self.rid}, " f"input_ids={self.origin_input_ids}, "


@dataclass
class Batch:
    reqs: List[Req]
    req_to_token_pool: ReqToTokenPool
    token_to_kv_pool: TokenToKVPool
    tree_cache: RadixCache

    # batched arguments to model runner
    input_ids: torch.Tensor = None
    req_pool_indices: torch.Tensor = None
    seq_lens: torch.Tensor = None
    prefix_lens: torch.Tensor = None
    position_ids_offsets: torch.Tensor = None
    out_cache_loc: torch.Tensor = None
    out_cache_cont_start: torch.Tensor = None
    out_cache_cont_end: torch.Tensor = None

    # for processing logprobs
    return_logprob: bool = False
    top_logprobs_nums: List[int] = None

    # for multimodal
    pixel_values: List[torch.Tensor] = None
    image_sizes: List[List[int]] = None
    image_offsets: List[int] = None

    # other arguments for control
    output_ids: torch.Tensor = None
    extend_num_tokens: int = None

    # batched sampling params
    temperatures: torch.Tensor = None
    top_ps: torch.Tensor = None
    top_ks: torch.Tensor = None
    frequency_penalties: torch.Tensor = None
    presence_penalties: torch.Tensor = None
    logit_bias: torch.Tensor = None

    @classmethod
    def init_new(cls, reqs, req_to_token_pool, token_to_kv_pool, tree_cache):
        return_logprob = any(req.return_logprob for req in reqs)

        return cls(
            reqs=reqs,
            req_to_token_pool=req_to_token_pool,
            token_to_kv_pool=token_to_kv_pool,
            tree_cache=tree_cache,
            return_logprob=return_logprob,
        )

    def is_empty(self):
        return len(self.reqs) == 0

    def prepare_for_extend(self, vocab_size: int, int_token_logit_bias: torch.Tensor):
        device = "cuda"
        bs = len(self.reqs)
        reqs = self.reqs
        input_ids = [r.input_ids[len(r.prefix_indices) :] for r in reqs]
        prefix_indices = [r.prefix_indices for r in reqs]

        # Handle prefix
        flatten_input_ids = []
        extend_lens = []
        prefix_lens = []
        seq_lens = []

        req_pool_indices = self.req_to_token_pool.alloc(bs)
        req_pool_indices_cpu = req_pool_indices.cpu().numpy()
        for i in range(bs):
            flatten_input_ids.extend(input_ids[i])
            extend_lens.append(len(input_ids[i]))

            if len(prefix_indices[i]) == 0:
                prefix_lens.append(0)
            else:
                prefix_lens.append(len(prefix_indices[i]))
                self.req_to_token_pool.req_to_token[req_pool_indices_cpu[i]][
                    : len(prefix_indices[i])
                ] = prefix_indices[i]

            seq_lens.append(prefix_lens[-1] + extend_lens[-1])

        position_ids_offsets = torch.zeros((bs,), dtype=torch.int32, device=device)

        # Alloc mem
        seq_lens, prefix_lens = np.array(seq_lens), np.array(prefix_lens)
        extend_num_tokens = seq_lens.sum() - prefix_lens.sum()
        out_cache_loc = self.token_to_kv_pool.alloc(extend_num_tokens)
        if out_cache_loc is None:
            self.tree_cache.evict(extend_num_tokens, self.token_to_kv_pool.dec_refs)
            out_cache_loc = self.token_to_kv_pool.alloc(extend_num_tokens)

            if out_cache_loc is None:
                print("Prefill out of memory. This should never happen.")
                self.tree_cache.pretty_print()
                exit()

        pt = 0
        for i in range(bs):
            self.req_to_token_pool.req_to_token[req_pool_indices_cpu[i]][
                prefix_lens[i] : prefix_lens[i] + extend_lens[i]
            ] = out_cache_loc[pt : pt + extend_lens[i]]
            pt += extend_lens[i]

        # Handle logit bias but only allocate when needed
        logit_bias = None
        for i in range(bs):
            if reqs[i].sampling_params.dtype == "int":
                if logit_bias is None:
                    logit_bias = torch.zeros(
                        (bs, vocab_size), dtype=torch.float32, device=device
                    )
                logit_bias[i] = int_token_logit_bias

        # Set fields
        self.input_ids = torch.tensor(
            flatten_input_ids, dtype=torch.int32, device=device
        )
        self.pixel_values = [r.pixel_values for r in reqs]
        self.image_sizes = [r.image_size for r in reqs]
        self.image_offsets = [
            r.image_offset - p_len for r, p_len in zip(reqs, prefix_lens)
        ]
        self.req_pool_indices = req_pool_indices
        self.seq_lens = torch.tensor(seq_lens, dtype=torch.int32, device=device)
        self.prefix_lens = torch.tensor(prefix_lens, dtype=torch.int32, device=device)
        self.position_ids_offsets = position_ids_offsets
        self.extend_num_tokens = extend_num_tokens
        self.out_cache_loc = out_cache_loc
        self.top_logprobs_nums = [r.top_logprobs_num for r in reqs]

        self.temperatures = torch.tensor(
            [r.sampling_params.temperature for r in reqs],
            dtype=torch.float,
            device=device,
        ).view(-1, 1)
        self.top_ps = torch.tensor(
            [r.sampling_params.top_p for r in reqs], dtype=torch.float, device=device
        ).view(-1, 1)
        self.top_ks = torch.tensor(
            [r.sampling_params.top_k for r in reqs], dtype=torch.int, device=device
        ).view(-1, 1)
        self.frequency_penalties = torch.tensor(
            [r.sampling_params.frequency_penalty for r in reqs],
            dtype=torch.float,
            device=device,
        )
        self.presence_penalties = torch.tensor(
            [r.sampling_params.presence_penalty for r in reqs],
            dtype=torch.float,
            device=device,
        )
        self.logit_bias = logit_bias

    def check_decode_mem(self):
        bs = len(self.reqs)
        if self.token_to_kv_pool.available_size() >= bs:
            return True

        self.tree_cache.evict(bs, self.token_to_kv_pool.dec_refs)

        if self.token_to_kv_pool.available_size() >= bs:
            return True

        return False

    def retract_decode(self):
        sorted_indices = [i for i in range(len(self.reqs))]
        # TODO(lsyin): improve the priority of retraction
        sorted_indices.sort(
            key=lambda i: (len(self.reqs[i].output_ids), -len(self.reqs[i].input_ids)),
            reverse=True,
        )

        retracted_reqs = []
        seq_lens_cpu = self.seq_lens.cpu().numpy()
        req_pool_indices_cpu = self.req_pool_indices.cpu().numpy()
        while self.token_to_kv_pool.available_size() < len(self.reqs):
            idx = sorted_indices.pop()
            req = self.reqs[idx]
            retracted_reqs.append(req)

            # TODO: apply more fine-grained retraction
            last_uncached_pos = len(req.prefix_indices)
            token_indices = self.req_to_token_pool.req_to_token[
                req_pool_indices_cpu[idx]
            ][last_uncached_pos : seq_lens_cpu[idx]]
            self.token_to_kv_pool.dec_refs(token_indices)

            # release the last node
            self.tree_cache.dec_lock_ref(req.last_node)

            cur_output_str = req.partial_decode(req.output_ids)
            req.prev_output_str = req.prev_output_str + cur_output_str
            req.prev_output_ids.extend(req.output_ids)

            req.prefix_indices = None
            req.last_node = None
            req.extend_input_len = 0
            req.output_ids = []

            # For incremental logprobs
            req.last_update_decode_tokens = 0
            req.logprob_start_len = 10**9

        self.filter_batch(sorted_indices)

        return retracted_reqs

    def check_for_jump_forward(self, model_runner):
        jump_forward_reqs = []
        filter_indices = [i for i in range(len(self.reqs))]

        req_pool_indices_cpu = None

        for i, req in enumerate(self.reqs):
            if req.jump_forward_map is not None:
                res = req.jump_forward_map.jump_forward(req.regex_fsm_state)
                if res is not None:
                    jump_forward_str, next_state = res
                    if len(jump_forward_str) <= 1:
                        continue

                    if req_pool_indices_cpu is None:
                        req_pool_indices_cpu = self.req_pool_indices.tolist()

                    # insert the old request into tree_cache
                    self.tree_cache.cache_req(
                        token_ids=tuple(req.input_ids + req.output_ids)[:-1],
                        last_uncached_pos=len(req.prefix_indices),
                        req_pool_idx=req_pool_indices_cpu[i],
                    )

                    # unlock the last node
                    self.tree_cache.dec_lock_ref(req.last_node)

                    # jump-forward
                    req.jump_forward_and_retokenize(jump_forward_str, next_state)

                    # re-applying image padding
                    if req.pixel_values is not None:
                        (
                            req.origin_input_ids,
                            req.image_offset,
                        ) = model_runner.model.pad_input_ids(
                            req.origin_input_ids_unpadded,
                            req.pad_value,
                            req.pixel_values.shape,
                            req.image_size,
                        )

                    jump_forward_reqs.append(req)
                    filter_indices.remove(i)

        if len(filter_indices) < len(self.reqs):
            self.filter_batch(filter_indices)

        return jump_forward_reqs

    def prepare_for_decode(self, input_ids=None):
        if input_ids is None:
            input_ids = [
                r.output_ids[-1] if r.output_ids else r.input_ids[-1] for r in self.reqs
            ]
        self.input_ids = torch.tensor(input_ids, dtype=torch.int32, device="cuda")
        self.seq_lens.add_(1)
        self.prefix_lens = None

        # Alloc mem
        bs = len(self.reqs)
        alloc_res = self.token_to_kv_pool.alloc_contiguous(bs)
        if alloc_res is None:
            self.out_cache_loc = self.token_to_kv_pool.alloc(bs)

            if self.out_cache_loc is None:
                print("Decode out of memory. This should never happen.")
                self.tree_cache.pretty_print()
                exit()

            self.out_cache_cont_start = None
            self.out_cache_cont_end = None
        else:
            self.out_cache_loc = alloc_res[0]
            self.out_cache_cont_start = alloc_res[1]
            self.out_cache_cont_end = alloc_res[2]

        self.req_to_token_pool.req_to_token[
            self.req_pool_indices, self.seq_lens - 1
        ] = self.out_cache_loc

    def filter_batch(self, unfinished_indices: List[int]):
        self.reqs = [self.reqs[i] for i in unfinished_indices]
        new_indices = torch.tensor(unfinished_indices, dtype=torch.int32, device="cuda")
        self.seq_lens = self.seq_lens[new_indices]
        self.input_ids = None
        self.req_pool_indices = self.req_pool_indices[new_indices]
        self.prefix_lens = None
        self.position_ids_offsets = self.position_ids_offsets[new_indices]
        self.out_cache_loc = self.out_cache_cont_start = self.out_cache_cont_end = None
        self.top_logprobs_nums = [self.top_logprobs_nums[i] for i in unfinished_indices]
        self.return_logprob = any(req.return_logprob for req in self.reqs)

        for item in [
            "temperatures",
            "top_ps",
            "top_ks",
            "frequency_penalties",
            "presence_penalties",
            "logit_bias",
        ]:
            self_val = getattr(self, item, None)
            # logit_bias can be None
            if self_val is not None:
                setattr(self, item, self_val[new_indices])

    def merge(self, other: "Batch"):
        self.reqs.extend(other.reqs)

        self.req_pool_indices = torch.concat(
            [self.req_pool_indices, other.req_pool_indices]
        )
        self.seq_lens = torch.concat([self.seq_lens, other.seq_lens])
        self.prefix_lens = None
        self.position_ids_offsets = torch.concat(
            [self.position_ids_offsets, other.position_ids_offsets]
        )
        self.out_cache_loc = self.out_cache_cont_start = self.out_cache_cont_end = None
        self.top_logprobs_nums.extend(other.top_logprobs_nums)
        self.return_logprob = any(req.return_logprob for req in self.reqs)

        for item in [
            "temperatures",
            "top_ps",
            "top_ks",
            "frequency_penalties",
            "presence_penalties",
        ]:
            self_val = getattr(self, item, None)
            other_val = getattr(other, item, None)
            setattr(self, item, torch.concat([self_val, other_val]))

        # logit_bias can be None
        if self.logit_bias is not None or other.logit_bias is not None:
            vocab_size = (
                self.logit_bias.shape[1]
                if self.logit_bias is not None
                else other.logit_bias.shape[1]
            )
            if self.logit_bias is None:
                self.logit_bias = torch.zeros(
                    (len(self.reqs), vocab_size), dtype=torch.float32, device="cuda"
                )
            if other.logit_bias is None:
                other.logit_bias = torch.zeros(
                    (len(other.reqs), vocab_size), dtype=torch.float32, device="cuda"
                )
            self.logit_bias = torch.concat([self.logit_bias, other.logit_bias])

    def sample(self, logits: torch.Tensor):
        # Post process logits
        logits = logits.contiguous()
        logits.div_(self.temperatures)
        if self.logit_bias is not None:
            logits.add_(self.logit_bias)

        has_regex = any(req.regex_fsm is not None for req in self.reqs)
        if has_regex:
            allowed_mask = torch.empty_like(logits[0], dtype=torch.bool)
            for i, req in enumerate(self.reqs):
                if req.regex_fsm is not None:
                    allowed_mask.zero_()
                    allowed_mask[
                        req.regex_fsm.allowed_token_ids(req.regex_fsm_state)
                    ] = 1
                    logits[i].masked_fill_(~allowed_mask, float("-inf"))

        # TODO(lmzheng): apply penalty
        probs = torch.softmax(logits, dim=-1)
        probs_sort, probs_idx = _top_p_top_k(probs, self.top_ps, self.top_ks)
        sampled_index = torch.multinomial(probs_sort, num_samples=1)
        batch_next_token_ids = torch.gather(probs_idx, dim=1, index=sampled_index).view(
            -1
        )
        batch_next_token_probs = torch.gather(
            probs_sort, dim=1, index=sampled_index
        ).view(-1)

        if has_regex:
            batch_next_token_ids_cpu = batch_next_token_ids.cpu().numpy()
            for i, req in enumerate(self.reqs):
                if req.regex_fsm is not None:
                    req.regex_fsm_state = req.regex_fsm.next_state(
                        req.regex_fsm_state, batch_next_token_ids_cpu[i]
                    )

        return batch_next_token_ids, batch_next_token_probs


def _top_p_top_k(probs: torch.Tensor, top_ps: torch.Tensor, top_ks: torch.Tensor):
    probs_sort, probs_idx = probs.sort(dim=-1, descending=True)
    probs_sum = torch.cumsum(probs_sort, dim=-1)
    probs_sort[(probs_sum - probs_sort) > top_ps] = 0.0
    probs_sort[
        torch.arange(0, probs.shape[-1], device=probs.device).view(1, -1) >= top_ks
    ] = 0.0
    probs_sort.div_(probs_sort.max(dim=-1, keepdim=True)[0])
    return probs_sort, probs_idx
