"""The interpreter that executes SGL programs"""

import asyncio
import multiprocessing
import queue
import threading
import uuid
from concurrent.futures import ThreadPoolExecutor
from contextlib import contextmanager
from typing import Any, Callable, Dict, List, Optional, Union

import tqdm
from sglang.global_config import global_config
from sglang.lang.ir import (
    SglCommitLazy,
    SglConcateAndAppend,
    SglConstantText,
    SglExpr,
    SglExprList,
    SglFunction,
    SglGen,
    SglImage,
    SglRoleBegin,
    SglRoleEnd,
    SglSelect,
    SglVariable,
    SglVarScopeBegin,
    SglVarScopeEnd,
)
from sglang.utils import encode_image_base64


def run_internal(state, program, func_args, func_kwargs, sync):
    try:
        state.ret_value = program.func(state, *func_args, **func_kwargs)
    except Exception as e:
        raise e
    finally:
        state.stream_executor.end()

    if sync:
        state.stream_executor.sync()

    if global_config.verbosity >= 2:
        print(state.text())


def run_program(
    program, backend, func_args, func_kwargs, default_sampling_para, stream, sync=False
):
    if hasattr(backend, "endpoint"):
        backend = backend.endpoint
    assert backend is not None, "Please specify a backend"

    func_kwargs.update(program.bind_arguments)
    stream_executor = StreamExecutor(
        backend, func_kwargs, default_sampling_para, chat_template=None, stream=stream
    )
    state = ProgramState(stream_executor)

    if stream:
        t = threading.Thread(
            target=run_internal, args=(state, program, func_args, func_kwargs, sync)
        )
        t.start()
        return state
    else:
        run_internal(state, program, func_args, func_kwargs, sync)
        return state


def run_program_batch(
    program,
    backend,
    batch_arguments,
    default_sampling_para,
    num_threads,
    progress_bar,
):
    if hasattr(backend, "endpoint"):
        backend = backend.endpoint

    # Extract prefix by tracing and cache it
    if len(batch_arguments) > 1:
        pin_program(program, backend)

    # Run all programs
    if num_threads == "auto":
        num_threads = max(96, multiprocessing.cpu_count() * 16)
    num_threads = min(num_threads, len(batch_arguments))

    if num_threads == 1:
        rets = []
        for arguments in batch_arguments:
            rets.append(
                run_program(
                    program, backend, (), arguments, default_sampling_para, False, True
                )
            )
    else:
        if progress_bar:
            pbar = tqdm.tqdm(total=len(batch_arguments))

        with ThreadPoolExecutor(num_threads) as executor:
            futures = []
            for arguments in batch_arguments:
                futures.append(
                    executor.submit(
                        run_program,
                        program,
                        backend,
                        (),
                        arguments,
                        default_sampling_para,
                        False,
                        True,
                    )
                )
                if progress_bar:
                    futures[-1].add_done_callback(lambda _: pbar.update())

            rets = [f.result() for f in futures]
        rets[-1].sync()

        if progress_bar:
            pbar.close()

    return rets


def pin_program(program, backend):
    if global_config.enable_prefix_sharing and program.pin_prefix_rid is None:
        # TODO: handle multiple backends
        from sglang.lang.tracer import extract_prefix_by_tracing

        prefix = extract_prefix_by_tracing(program, backend)
        if prefix and len(prefix) > 64:
            prefix_rid = backend.cache_prefix(prefix)
            program.pin_prefix_rid = prefix_rid
            return prefix_rid
    return None


def unpin_program(program, backend):
    pass


class StreamExecutor:
    """A stream executor that executes SGL expressions in a background thread."""

    def __init__(
        self,
        backend,
        arguments,
        default_sampling_para,
        chat_template,
        stream,
        use_thread=True,
    ):
        self.sid = uuid.uuid4().hex
        self.backend = backend
        self.arguments: Dict[str, Any] = arguments
        self.default_sampling_para = default_sampling_para
        self.stream = stream

        self.variables = {}  # Dict[name: str -> value: str]
        self.variable_event = {}  # Dict[name: str -> event: threading.Event]
        self.meta_info = {}  # Dict[name: str -> info: str]
        self.is_finished = False

        # For completion
        self.text_ = ""  # The full text

        # For chat
        self.messages_ = []  # The messages in the OpenAI API format
        self.chat_template = chat_template or self.backend.get_chat_template()
        self.cur_role = None
        self.cur_role_begin_pos = None

        # For vision
        self.images_ = []
        self.cur_images = []

        # For fork/join
        self.fork_start_text_pos = None

        # Worker thread
        self.use_thread = use_thread
        if self.use_thread:
            self.queue = queue.Queue()
            self.worker = threading.Thread(target=self._thread_worker_func)
            self.worker.start()

        # For streaming
        if stream:
            self.stream_text_event = threading.Event()
            self.stream_var_event = {}
        else:
            self.stream_text_event = None
            self.stream_var_event = None

    def submit(self, expr: SglExpr):
        self._init_var_event(expr)

        if self.use_thread:
            self.queue.put(expr)
        else:
            self._execute(expr)

    def sync(self):
        if self.use_thread:
            self.queue.join()

    def get_var(self, name):
        if name in self.variable_event:
            self.variable_event[name].wait()
        return self.variables[name]

    def get_meta_info(self, name):
        if name in self.variable_event:
            self.variable_event[name].wait()
        ret = self.meta_info.get(name, None)
        return ret

    def fork(self, number: int, position_ids_offset: Optional[List[int]] = None):
        if number > 1:
            self.submit(SglCommitLazy())
            self.sync()

        number = int(number)

        exes = [
            StreamExecutor(
                self.backend,
                self.arguments,
                self.default_sampling_para,
                self.chat_template,
                self.stream,
            )
            for _ in range(number)
        ]
        for i in range(number):
            exes[i].variables = dict(self.variables)
            exes[i].text_ = str(self.text_)
            exes[i].messages_ = list(self.messages_)
            exes[i].cur_role = self.cur_role
            exes[i].fork_start_text_pos = len(self.text_)

        return exes

    def text(self):
        self.sync()
        return self.text_

    def messages(self):
        self.sync()
        return self.messages_

    def end(self):
        if self.use_thread:
            if self.worker.is_alive():
                self.queue.put(None)
        self.backend.end_program(self)

    def _thread_worker_func(self):
        while True:
            expr = self.queue.get()
            if expr is None:
                self.queue.task_done()
                break

            self._execute(expr)
            self.queue.task_done()
            if self.stream_text_event:
                self.stream_text_event.set()

        if self.stream_text_event:
            self.stream_text_event.set()

        self.is_finished = True

    def _execute(self, other):
        if isinstance(other, str):
            other = SglConstantText(other)

        assert isinstance(other, SglExpr), f"{other}"

        if isinstance(other, SglConstantText):
            self._execute_fill(other.value)
        elif isinstance(other, SglGen):
            self._execute_gen(other)
        elif isinstance(other, SglSelect):
            self._execute_select(other)
        elif isinstance(other, SglExprList):
            for x in other.expr_list:
                self._execute(x)
        elif isinstance(other, SglRoleBegin):
            self._execute_role_begin(other)
        elif isinstance(other, SglRoleEnd):
            self._execute_role_end(other)
        elif isinstance(other, SglImage):
            self._execute_image(other)
        elif isinstance(other, SglVariable):
            self._execute_variable(other)
        elif isinstance(other, SglVarScopeBegin):
            self._execute_var_scope_begin(other)
        elif isinstance(other, SglVarScopeEnd):
            self._execute_var_scope_end(other)
        elif isinstance(other, SglCommitLazy):
            self._execute_commit_lazy_operations(other)
        elif isinstance(other, SglConcateAndAppend):
            if (
                global_config.enable_parallel_encoding
                and self.backend.support_concate_and_append
            ):
                self._execute_concatenate_and_append_kv_cache(other)
            else:
                self._execute_concatenate_and_append_text(other)
        else:
            raise ValueError(f"Unknown type: {type(other)}")

    def _execute_fill(self, value: str):
        value = str(value)
        self.text_ += value

    def _execute_image(self, expr: SglImage):
        path = expr.path

        base64_data = encode_image_base64(path)

        self.images_.append((path, base64_data))
        self.cur_images.append((path, base64_data))
        self.text_ += self.chat_template.image_token

        # if global_config.eager_fill_image:
        #     self.backend.fill_image(self)

    def _execute_gen(self, expr: SglGen):
        sampling_params = self._resolve_sampling_params(expr.sampling_params)
        name = expr.name

        if not self.stream:
            comp, meta_info = self.backend.generate(
                self, sampling_params=sampling_params
            )
            self.text_ += comp

            self.variables[name] = comp
            self.meta_info[name] = meta_info
            self.variable_event[name].set()
        else:
            generator = self.backend.generate_stream(
                self, sampling_params=sampling_params
            )

            self.stream_var_event[name].set()

            self.variables[name] = ""
            for comp, meta_info in generator:
                self.text_ += comp
                self.variables[name] += comp
                self.meta_info[name] = meta_info
                self.stream_var_event[name].set()
                self.stream_text_event.set()

            self.variable_event[name].set()
            self.stream_var_event[name].set()

    def _execute_select(self, expr: SglSelect):
        decision, normalized_prompt_logprob, prompt_logprob = self.backend.select(
            self, expr.choices, expr.temperature
        )
        if expr.name is not None:
            name = expr.name
            self.variables[name] = decision
            self.meta_info[name] = {
                "normalized_prompt_logprob": normalized_prompt_logprob,
                "prompt_logprob": prompt_logprob,
            }
            self.variable_event[name].set()
        self.text_ += decision

    def _execute_variable(self, expr: SglVariable):
        src_executor = expr.source_stream_executor
        value = src_executor.get_var(expr.name)
        self._execute_fill(value)

    def _execute_role_begin(self, expr: SglRoleBegin):
        assert self.cur_role is None, "Nested roles are not allowed."

        if len(self.messages_) == 0 and expr.role != "system":
            # Insert the default system message
            default_system = self.chat_template.default_system_prompt
            if default_system:
                self._execute_role_begin(SglRoleBegin("system"))
                self._execute_fill(default_system)
                self._execute_role_end(SglRoleEnd("system"))

        self.cur_role = expr.role

        prefix, _ = self.chat_template.get_prefix_and_suffix(expr.role, self.messages_)

        self._execute_fill(prefix)
        self.cur_role_begin_pos = len(self.text_)

    def _execute_role_end(self, expr: SglRoleEnd):
        new_text = self.text_[self.cur_role_begin_pos :].lstrip()

        _, suffix = self.chat_template.get_prefix_and_suffix(expr.role, self.messages_)
        self._execute_fill(suffix)

        if self.cur_images:
            # OpenAI vision API format
            last_msg = {
                "role": expr.role,
                "content": [{"type": "text", "text": new_text}],
            }
            for image_path, image_base64_data in self.cur_images:
                last_msg["content"].append(
                    {
                        "type": "image_url",
                        "image_url": {
                            "url": f"data:image/jpeg;base64,{image_base64_data}"
                        },
                    }
                )
            self.messages_.append(last_msg)
            self.cur_images = []
        else:
            # OpenAI chat API format
            self.messages_.append({"role": expr.role, "content": new_text})

        self.cur_role = None

    def _execute_var_scope_begin(self, expr: SglVarScopeBegin):
        self.variables[expr.name] = int(len(self.text_))

    def _execute_var_scope_end(self, expr: SglVarScopeEnd):
        self.variables[expr.name] = self.text_[self.variables[expr.name] :]
        self.variable_event[expr.name].set()

    def _execute_commit_lazy_operations(self, expr: SglCommitLazy):
        self.backend.commit_lazy_operations(self)

    def _execute_concatenate_and_append_text(self, expr: SglConcateAndAppend):
        new_text = ""
        for s in expr.states:
            exe = s.stream_executor
            exe.sync()
            new_text += exe.text_[exe.fork_start_text_pos :]

        self._execute_fill(new_text)

    def _execute_concatenate_and_append_kv_cache(self, expr: SglConcateAndAppend):
        self_len = len(self.text_)

        for i, s in enumerate(expr.states):
            exe = s.stream_executor
            exe.submit(SglCommitLazy())

        for i, s in enumerate(expr.states):
            exe = s.stream_executor
            exe.sync()
            assert exe.fork_start_text_pos == self_len
            self.text_ += exe.text_[exe.fork_start_text_pos :]

        src_rids = [state.stream_executor.sid for state in expr.states]
        self.backend.concatenate_and_append(src_rids, self.sid)

    def _init_var_event(self, expr):
        if isinstance(expr, (SglGen, SglSelect, SglVarScopeBegin)):
            self.variable_event[expr.name] = threading.Event()
            if self.stream:
                self.stream_var_event[expr.name] = threading.Event()
        elif isinstance(expr, SglExprList):
            for e in expr.expr_list:
                self._init_var_event(e)

    def _resolve_sampling_params(self, sampling_params):
        clone = None
        for item in [
            "max_new_tokens",
            "stop",
            "temperature",
            "top_p",
            "top_k",
            "frequency_penalty",
            "presence_penalty",
            "ignore_eos",
            "dtype",
            "regex",
        ]:
            value = getattr(sampling_params, item, None)
            if value is not None:
                if clone is None:
                    clone = self.default_sampling_para.clone()
                setattr(clone, item, value)

        if self.chat_template.stop_str:
            if not clone:
                clone = self.default_sampling_para.clone()
            clone.stop += self.chat_template.stop_str

        return clone or self.default_sampling_para

    def __del__(self):
        self.end()


class ProgramState:
    """The state of an SGL program."""

    def __init__(self, stream_executor: StreamExecutor):
        self.stream_executor = stream_executor

    def _role_common(self, name: str, expr: Optional[SglExpr] = None):
        if expr is not None:
            self.stream_executor.submit(
                SglExprList([SglRoleBegin(name), expr, SglRoleEnd(name)])
            )
        else:

            @contextmanager
            def role_scope():
                self.stream_executor.submit(SglRoleBegin(name))
                yield
                self.stream_executor.submit(SglRoleEnd(name))

            return role_scope()

    def system(self, expr: Optional[SglExpr] = None):
        return self._role_common("system", expr)

    def user(self, expr: Optional[SglExpr] = None):
        return self._role_common("user", expr)

    def assistant(self, expr: Optional[SglExpr] = None):
        return self._role_common("assistant", expr)

    @contextmanager
    def var_scope(self, name: str):
        self.stream_executor.submit(SglVarScopeBegin(name))
        yield
        self.stream_executor.submit(SglVarScopeEnd(name))

    def fork(self, number: int = 1, position_ids_offset: Optional[List[int]] = None):
        stream_executors = self.stream_executor.fork(number, position_ids_offset)
        states = [ProgramState(x) for x in stream_executors]
        state_group = ProgramStateGroup(states, self)
        return state_group

    @contextmanager
    def copy(self, position_ids_offset: Optional[List[int]] = None):
        state_group = self.fork(1, position_ids_offset)
        try:
            yield state_group[0]
        finally:
            state_group.join()

    def text(self):
        return self.stream_executor.text()

    def messages(self):
        return self.stream_executor.messages()

    def sync(self):
        return self.stream_executor.sync()

    def text_iter(self, var_name=None):
        if self.stream_executor.stream:
            prev = 0
            if var_name is None:
                event = self.stream_executor.stream_text_event
                while True:
                    event.wait()
                    event.clear()
                    out = str(self.stream_executor.text_[prev:])
                    prev += len(out)
                    if out:
                        yield out
                    if self.stream_executor.is_finished:
                        break
            else:
                event = self.stream_executor.stream_var_event[var_name]
                while True:
                    event.wait()
                    event.clear()
                    out = str(self.stream_executor.variables[var_name][prev:])
                    prev += len(out)
                    if out:
                        yield out
                    if self.stream_executor.variable_event[var_name].is_set():
                        break
        else:
            if var_name is None:
                yield self.text()
            else:
                yield self.get_var(name)

    async def text_async_iter(self, var_name=None, return_meta_data=False):
        loop = asyncio.get_running_loop()

        if self.stream_executor.stream:
            prev = 0
            if var_name is None:
                event = self.stream_executor.stream_text_event
                while True:
                    await loop.run_in_executor(None, event.wait)
                    event.clear()
                    out = str(self.stream_executor.text_[prev:])
                    prev += len(out)
                    if out:
                        yield out
                    if self.stream_executor.is_finished:
                        break
            else:
                event = self.stream_executor.stream_var_event[var_name]
                while True:
                    await loop.run_in_executor(None, event.wait)
                    event.clear()
                    out = str(self.stream_executor.variables[var_name][prev:])
                    prev += len(out)
                    if out:
                        if return_meta_data:
                            yield out, self.stream_executor.meta_info[var_name]
                        else:
                            yield out
                    if self.stream_executor.variable_event[var_name].is_set():
                        break
        else:
            if var_name is None:
                yield self.text()
            else:
                yield self.get_var(name)

    def get_var(self, name):
        return self.stream_executor.get_var(name)

    def get_meta_info(self, name):
        return self.stream_executor.get_meta_info(name)

    def __iadd__(self, other):
        self.stream_executor.submit(other)
        return self

    def __getitem__(self, name):
        return self.get_var(name)

    def __del__(self):
        self.stream_executor.end()

    def __repr__(self) -> str:
        return f"ProgramState({self.text()})"


class ProgramStateGroup:
    def __init__(
        self, states: List[ProgramState], src_state: Optional[ProgramState] = None
    ):
        self.states = states
        self.src_state = src_state

    def join(self, mode: str = "gather_variable"):
        if mode == "gather_variable":
            # Copy variables back
            src_vars = self.src_state.stream_executor.variables
            src_var_set = set(src_vars.keys())
            for child_state in self.states:
                child_state.stream_executor.sync()
                child_vars = child_state.stream_executor.variables
                new_vars = set(child_vars.keys()) - src_var_set

                for k in new_vars:
                    if k in src_vars:
                        src_vars[k].append(child_vars[k])
                    else:
                        src_vars[k] = [child_vars[k]]
        elif mode == "concate_and_append":
            # Concatenate and append KV cache
            self.src_state += SglConcateAndAppend(self.states)
            # Need a sync here. Otherwise, `states` can be deleted.
            self.src_state.stream_executor.sync()
        else:
            raise ValueError(f"Invalid join mode: {mode}")

        for s in self.states:
            s.stream_executor.end()

    def __getitem__(self, i: int):
        return self.states[i]

    def __setitem__(self, i: int, value):
        assert self.states[i] == value

    def __iadd__(self, other):
        if isinstance(other, Callable):
            # lambda function
            for i in range(len(self.states)):
                self.states[i] += other(i)
        elif isinstance(other, SglExpr):
            for i in range(len(self.states)):
                self.states[i] += other
        elif isinstance(other, (list, tuple)):
            for i in range(len(self.states)):
                self.states[i] += other[i]
        else:
            raise ValueError(f"Invalid value: {other}")

        return self
