app/api_helpers.py

import json
import time
import math
import asyncio
import base64
import random 
from typing import List, Dict, Any, Callable, Union, Optional

from fastapi.responses import JSONResponse, StreamingResponse
from google.auth.transport.requests import Request as AuthRequest
from google.genai import types
from google.genai.types import GenerateContentResponse 
from google import genai
from openai import AsyncOpenAI 
from openai.types.chat import ChatCompletionMessage, ChatCompletionMessageToolCall
from openai.types.chat.chat_completion_chunk import ChoiceDeltaToolCall, ChoiceDeltaToolCallFunction

from models import OpenAIRequest, OpenAIMessage
from message_processing import (
    deobfuscate_text,
    convert_to_openai_format, 
    convert_chunk_to_openai,
    create_final_chunk,
    parse_gemini_response_for_reasoning_and_content, 
    extract_reasoning_by_tags
)
import config as app_config
from config import VERTEX_REASONING_TAG

class StreamingReasoningProcessor:
    def __init__(self, tag_name: str = VERTEX_REASONING_TAG):
        self.tag_name = tag_name
        self.open_tag = f"<{tag_name}>"
        self.close_tag = f"</{tag_name}>"
        self.tag_buffer = ""
        self.inside_tag = False
        self.reasoning_buffer = ""
        self.partial_tag_buffer = "" 

    def process_chunk(self, content: str) -> tuple[str, str]:
        if self.partial_tag_buffer:
            content = self.partial_tag_buffer + content
            self.partial_tag_buffer = ""
        self.tag_buffer += content
        processed_content = ""
        current_reasoning = ""
        while self.tag_buffer:
            if not self.inside_tag:
                open_pos = self.tag_buffer.find(self.open_tag)
                if open_pos == -1:
                    partial_match = False
                    for i in range(1, min(len(self.open_tag), len(self.tag_buffer) + 1)):
                        if self.tag_buffer[-i:] == self.open_tag[:i]:
                            partial_match = True
                            if len(self.tag_buffer) > i:
                                processed_content += self.tag_buffer[:-i]
                                self.partial_tag_buffer = self.tag_buffer[-i:]
                            else: self.partial_tag_buffer = self.tag_buffer
                            self.tag_buffer = ""
                            break
                    if not partial_match:
                        processed_content += self.tag_buffer
                        self.tag_buffer = ""
                    break
                else:
                    processed_content += self.tag_buffer[:open_pos]
                    self.tag_buffer = self.tag_buffer[open_pos + len(self.open_tag):]
                    self.inside_tag = True
            else: 
                close_pos = self.tag_buffer.find(self.close_tag)
                if close_pos == -1:
                    partial_match = False
                    for i in range(1, min(len(self.close_tag), len(self.tag_buffer) + 1)):
                        if self.tag_buffer[-i:] == self.close_tag[:i]:
                            partial_match = True
                            if len(self.tag_buffer) > i:
                                new_reasoning = self.tag_buffer[:-i]
                                self.reasoning_buffer += new_reasoning
                                if new_reasoning: current_reasoning = new_reasoning
                                self.partial_tag_buffer = self.tag_buffer[-i:]
                            else: self.partial_tag_buffer = self.tag_buffer
                            self.tag_buffer = ""
                            break
                    if not partial_match:
                        if self.tag_buffer:
                            self.reasoning_buffer += self.tag_buffer
                            current_reasoning = self.tag_buffer
                            self.tag_buffer = ""
                    break
                else:
                    final_reasoning_chunk = self.tag_buffer[:close_pos]
                    self.reasoning_buffer += final_reasoning_chunk
                    if final_reasoning_chunk: current_reasoning = final_reasoning_chunk
                    self.reasoning_buffer = "" 
                    self.tag_buffer = self.tag_buffer[close_pos + len(self.close_tag):]
                    self.inside_tag = False
        return processed_content, current_reasoning
    
    def flush_remaining(self) -> tuple[str, str]:
        remaining_content, remaining_reasoning = "", ""
        if self.partial_tag_buffer:
            remaining_content += self.partial_tag_buffer
            self.partial_tag_buffer = ""
        if not self.inside_tag:
            if self.tag_buffer: remaining_content += self.tag_buffer
        else:
            if self.reasoning_buffer: remaining_reasoning = self.reasoning_buffer
            if self.tag_buffer: remaining_content += self.tag_buffer
            self.inside_tag = False
        self.tag_buffer, self.reasoning_buffer = "", ""
        return remaining_content, remaining_reasoning

def create_openai_error_response(status_code: int, message: str, error_type: str) -> Dict[str, Any]:
    return {"error": {"message": message, "type": error_type, "code": status_code, "param": None}}

def create_generation_config(request: OpenAIRequest) -> Dict[str, Any]:
    config: Dict[str, Any] = {} 
    if request.temperature is not None: config["temperature"] = request.temperature
    if request.max_tokens is not None: config["max_output_tokens"] = request.max_tokens
    if request.top_p is not None: config["top_p"] = request.top_p
    if request.top_k is not None: config["top_k"] = request.top_k
    if request.stop is not None: config["stop_sequences"] = request.stop
    if request.seed is not None: config["seed"] = request.seed
    if request.n is not None: config["candidate_count"] = request.n
    
    config["safety_settings"] = [
            types.SafetySetting(category="HARM_CATEGORY_HATE_SPEECH", threshold="OFF"),
            types.SafetySetting(category="HARM_CATEGORY_DANGEROUS_CONTENT", threshold="OFF"),
            types.SafetySetting(category="HARM_CATEGORY_SEXUALLY_EXPLICIT", threshold="OFF"),
            types.SafetySetting(category="HARM_CATEGORY_HARASSMENT", threshold="OFF"),
            types.SafetySetting(category="HARM_CATEGORY_CIVIC_INTEGRITY", threshold="OFF")
    ]
    config["thinking_config"] = {"include_thoughts": True}

    # 1. Add tools (function declarations)
    function_declarations = []
    if request.tools:
        for tool in request.tools:
            if tool.get("type") == "function":
                # func_def = tool.get("function")
                func_def = tool
                if func_def:
                    # Extract only the fields accepted by the Gemini API
                    declaration = {
                        "name": func_def.get("name"),
                        "description": func_def.get("description"),
                    }
                    # Get parameters and remove the $schema field if it exists
                    parameters = func_def.get("parameters")
                    if isinstance(parameters, dict) and "$schema" in parameters:
                        parameters = parameters.copy()
                        del parameters["$schema"]
                    if parameters is not None:
                        declaration["parameters"] = parameters

                    # Remove keys with None values to keep the payload clean
                    declaration = {k: v for k, v in declaration.items() if v is not None}
                    if declaration.get("name"):  # Ensure name exists
                        function_declarations.append(declaration)

    if function_declarations:
        config["tools"] = [{"function_declarations": function_declarations}]

    # 2. Add tool_config (based on tool_choice)
    tool_config = None
    if request.tool_choice:
        choice = request.tool_choice
        mode = None
        allowed_functions = None
        if isinstance(choice, str):
            if choice == "none":
                mode = "NONE"
            elif choice == "auto":
                mode = "AUTO"
        elif isinstance(choice, dict) and choice.get("type") == "function":
            func_name = choice.get("function", {}).get("name")
            if func_name:
                mode = "ANY"  # 'ANY' mode is used to force a specific function call
                allowed_functions = [func_name]
        
        # If a valid mode was parsed, build the tool_config
        if mode:
            config_dict = {"mode": mode}
            if allowed_functions:
                config_dict["allowed_function_names"] = allowed_functions
            tool_config = {"function_calling_config": config_dict}
    
    if tool_config:
        config["tool_config"] = tool_config
        
    return config


def is_gemini_response_valid(response: Any) -> bool:
    if response is None: return False
    if hasattr(response, 'text') and isinstance(response.text, str) and response.text.strip(): return True
    if hasattr(response, 'candidates') and response.candidates:
        for cand in response.candidates:
            if hasattr(cand, 'text') and isinstance(cand.text, str) and cand.text.strip(): return True
            if hasattr(cand, 'content') and hasattr(cand.content, 'parts') and cand.content.parts:
                for part in cand.content.parts:
                    if hasattr(part, 'function_call'): return True 
                    if hasattr(part, 'text') and isinstance(getattr(part, 'text', None), str) and getattr(part, 'text', '').strip(): return True
    return False

async def _chunk_openai_response_dict_for_sse(
    openai_response_dict: Dict[str, Any],
    response_id_override: Optional[str] = None, 
    model_name_override: Optional[str] = None
):
    resp_id = response_id_override or openai_response_dict.get("id", f"chatcmpl-fakestream-{int(time.time())}")
    model_name = model_name_override or openai_response_dict.get("model", "unknown")
    created_time = openai_response_dict.get("created", int(time.time()))
    
    choices = openai_response_dict.get("choices", [])
    if not choices: 
        yield f"data: {json.dumps({'id': resp_id, 'object': 'chat.completion.chunk', 'created': created_time, 'model': model_name, 'choices': [{'index': 0, 'delta': {}, 'finish_reason': 'error'}]})}\n\n"
        yield "data: [DONE]\n\n"
        return

    for choice_idx, choice in enumerate(choices): 
        message = choice.get("message", {})
        final_finish_reason = choice.get("finish_reason", "stop")

        if message.get("tool_calls"):
            tool_calls_list = message.get("tool_calls", [])
            for tc_item_idx, tool_call_item in enumerate(tool_calls_list):
                delta_tc_start = {
                    "tool_calls": [{
                        "index": tc_item_idx, 
                        "id": tool_call_item["id"],
                        "type": "function",
                        "function": {"name": tool_call_item["function"]["name"], "arguments": ""}
                    }]
                }
                yield f"data: {json.dumps({'id': resp_id, 'object': 'chat.completion.chunk', 'created': created_time, 'model': model_name, 'choices': [{'index': choice_idx, 'delta': delta_tc_start, 'finish_reason': None}]})}\n\n"
                await asyncio.sleep(0.01) 

                delta_tc_args = {
                    "tool_calls": [{
                        "index": tc_item_idx,
                        "id": tool_call_item["id"], 
                        "function": {"arguments": tool_call_item["function"]["arguments"]}
                    }]
                }
                yield f"data: {json.dumps({'id': resp_id, 'object': 'chat.completion.chunk', 'created': created_time, 'model': model_name, 'choices': [{'index': choice_idx, 'delta': delta_tc_args, 'finish_reason': None}]})}\n\n"
                await asyncio.sleep(0.01)
        
        elif message.get("content") is not None or message.get("reasoning_content") is not None : 
            reasoning_content = message.get("reasoning_content", "")
            actual_content = message.get("content") 

            if reasoning_content:
                delta_reasoning = {"reasoning_content": reasoning_content}
                yield f"data: {json.dumps({'id': resp_id, 'object': 'chat.completion.chunk', 'created': created_time, 'model': model_name, 'choices': [{'index': choice_idx, 'delta': delta_reasoning, 'finish_reason': None}]})}\n\n"
                if actual_content is not None: await asyncio.sleep(0.05)

            content_to_chunk = actual_content if actual_content is not None else ""
            if actual_content is not None:
                chunk_size = max(1, math.ceil(len(content_to_chunk) / 10)) if content_to_chunk else 1
                if not content_to_chunk and not reasoning_content : 
                    yield f"data: {json.dumps({'id': resp_id, 'object': 'chat.completion.chunk', 'created': created_time, 'model': model_name, 'choices': [{'index': choice_idx, 'delta': {'content': ''}, 'finish_reason': None}]})}\n\n"
                else:
                    for i in range(0, len(content_to_chunk), chunk_size):
                        yield f"data: {json.dumps({'id': resp_id, 'object': 'chat.completion.chunk', 'created': created_time, 'model': model_name, 'choices': [{'index': choice_idx, 'delta': {'content': content_to_chunk[i:i+chunk_size]}, 'finish_reason': None}]})}\n\n"
                        if len(content_to_chunk) > chunk_size: await asyncio.sleep(0.05)
        
        yield f"data: {json.dumps({'id': resp_id, 'object': 'chat.completion.chunk', 'created': created_time, 'model': model_name, 'choices': [{'index': choice_idx, 'delta': {}, 'finish_reason': final_finish_reason}]})}\n\n"

    yield "data: [DONE]\n\n"


async def gemini_fake_stream_generator( 
    gemini_client_instance: Any, 
    model_for_api_call: str, 
    prompt_for_api_call: List[types.Content],
    gen_config_dict_for_api_call: Dict[str, Any], 
    request_obj: OpenAIRequest,
    is_auto_attempt: bool
):
    model_name_for_log = getattr(gemini_client_instance, 'model_name', 'unknown_gemini_model_object')
    print(f"FAKE STREAMING (Gemini): Prep for '{request_obj.model}' (API model string: '{model_for_api_call}', client obj: '{model_name_for_log}')")
    
    api_call_task = asyncio.create_task(
        gemini_client_instance.aio.models.generate_content(
            model=model_for_api_call, 
            contents=prompt_for_api_call, 
            config=gen_config_dict_for_api_call # Pass the dictionary directly
        )
    )

    outer_keep_alive_interval = app_config.FAKE_STREAMING_INTERVAL_SECONDS
    if outer_keep_alive_interval > 0:
        while not api_call_task.done():
            keep_alive_data = {"id": "chatcmpl-keepalive", "object": "chat.completion.chunk", "created": int(time.time()), "model": request_obj.model, "choices": [{"delta": {"content": ""}, "index": 0, "finish_reason": None}]}
            yield f"data: {json.dumps(keep_alive_data)}\n\n"
            await asyncio.sleep(outer_keep_alive_interval)
    
    try:
        raw_gemini_response = await api_call_task 
        openai_response_dict = convert_to_openai_format(raw_gemini_response, request_obj.model)
        
        if hasattr(raw_gemini_response, 'prompt_feedback') and \
           hasattr(raw_gemini_response.prompt_feedback, 'block_reason') and \
           raw_gemini_response.prompt_feedback.block_reason:
            block_message = f"Response blocked by Gemini safety filter: {raw_gemini_response.prompt_feedback.block_reason}"
            if hasattr(raw_gemini_response.prompt_feedback, 'block_reason_message') and \
               raw_gemini_response.prompt_feedback.block_reason_message:
                block_message += f" (Message: {raw_gemini_response.prompt_feedback.block_reason_message})"
            raise ValueError(block_message)

        async for chunk_sse in _chunk_openai_response_dict_for_sse(
            openai_response_dict=openai_response_dict
        ):
            yield chunk_sse

    except Exception as e_outer_gemini:
        err_msg_detail = f"Error in gemini_fake_stream_generator (model: '{request_obj.model}'): {type(e_outer_gemini).__name__} - {str(e_outer_gemini)}"
        print(f"ERROR: {err_msg_detail}")
        sse_err_msg_display = str(e_outer_gemini)
        if len(sse_err_msg_display) > 512: sse_err_msg_display = sse_err_msg_display[:512] + "..."
        err_resp_sse = create_openai_error_response(500, sse_err_msg_display, "server_error")
        json_payload_error = json.dumps(err_resp_sse)
        if not is_auto_attempt:
            yield f"data: {json_payload_error}\n\n"
            yield "data: [DONE]\n\n"
        if is_auto_attempt: raise


async def openai_fake_stream_generator( 
    openai_client: Union[AsyncOpenAI, Any], 
    openai_params: Dict[str, Any],
    openai_extra_body: Dict[str, Any],
    request_obj: OpenAIRequest,
    is_auto_attempt: bool
):
    api_model_name = openai_params.get("model", "unknown-openai-model")
    print(f"FAKE STREAMING (OpenAI Direct): Prep for '{request_obj.model}' (API model: '{api_model_name}')")
    response_id = f"chatcmpl-openaidirectfake-{int(time.time())}"
    
    async def _openai_api_call_task():
        params_for_call = openai_params.copy()
        params_for_call['stream'] = False 
        return await openai_client.chat.completions.create(**params_for_call, extra_body=openai_extra_body)

    api_call_task = asyncio.create_task(_openai_api_call_task())
    outer_keep_alive_interval = app_config.FAKE_STREAMING_INTERVAL_SECONDS
    if outer_keep_alive_interval > 0:
        while not api_call_task.done():
            keep_alive_data = {"id": "chatcmpl-keepalive", "object": "chat.completion.chunk", "created": int(time.time()), "model": request_obj.model, "choices": [{"delta": {"content": ""}, "index": 0, "finish_reason": None}]}
            yield f"data: {json.dumps(keep_alive_data)}\n\n"
            await asyncio.sleep(outer_keep_alive_interval)

    try:
        raw_response_obj = await api_call_task 
        openai_response_dict = raw_response_obj.model_dump(exclude_unset=True, exclude_none=True)

        if openai_response_dict.get("choices") and \
           isinstance(openai_response_dict["choices"], list) and \
           len(openai_response_dict["choices"]) > 0:
            
            first_choice_dict_item = openai_response_dict["choices"] 
            if first_choice_dict_item and isinstance(first_choice_dict_item, dict) : 
                choice_message_ref = first_choice_dict_item.get("message", {}) 
                original_content = choice_message_ref.get("content")
                if isinstance(original_content, str):
                    reasoning_text, actual_content = extract_reasoning_by_tags(original_content, VERTEX_REASONING_TAG)
                    choice_message_ref["content"] = actual_content
                    if reasoning_text: 
                        choice_message_ref["reasoning_content"] = reasoning_text
        
        async for chunk_sse in _chunk_openai_response_dict_for_sse(
            openai_response_dict=openai_response_dict,
            response_id_override=response_id, 
            model_name_override=request_obj.model
        ):
            yield chunk_sse
            
    except Exception as e_outer: 
        err_msg_detail = f"Error in openai_fake_stream_generator (model: '{request_obj.model}'): {type(e_outer).__name__} - {str(e_outer)}"
        print(f"ERROR: {err_msg_detail}")
        sse_err_msg_display = str(e_outer)
        if len(sse_err_msg_display) > 512: sse_err_msg_display = sse_err_msg_display[:512] + "..."
        err_resp_sse = create_openai_error_response(500, sse_err_msg_display, "server_error")
        json_payload_error = json.dumps(err_resp_sse)
        if not is_auto_attempt:
            yield f"data: {json_payload_error}\n\n"
            yield "data: [DONE]\n\n"
        if is_auto_attempt: raise


async def execute_gemini_call(
    current_client: Any, 
    model_to_call: str,  
    prompt_func: Callable[[List[OpenAIMessage]], List[types.Content]], 
    gen_config_dict: Dict[str, Any], 
    request_obj: OpenAIRequest, 
    is_auto_attempt: bool = False
):
    actual_prompt_for_call = prompt_func(request_obj.messages)
    client_model_name_for_log = getattr(current_client, 'model_name', 'unknown_direct_client_object')
    print(f"INFO: execute_gemini_call for requested API model '{model_to_call}', using client object with internal name '{client_model_name_for_log}'. Original request model: '{request_obj.model}'")
    
    if request_obj.stream:
        if app_config.FAKE_STREAMING_ENABLED:
            return StreamingResponse(
                gemini_fake_stream_generator(
                    current_client, model_to_call, actual_prompt_for_call,
                    gen_config_dict, 
                    request_obj, is_auto_attempt
                ), media_type="text/event-stream"
            )
        else: # True Streaming
            response_id_for_stream = f"chatcmpl-realstream-{int(time.time())}"
            async def _gemini_real_stream_generator_inner():
                try:
                    stream_gen_obj = await current_client.aio.models.generate_content_stream(
                        model=model_to_call, 
                        contents=actual_prompt_for_call,
                        config=gen_config_dict # Pass the dictionary directly
                    )
                    async for chunk_item_call in stream_gen_obj:
                        yield convert_chunk_to_openai(chunk_item_call, request_obj.model, response_id_for_stream, 0)
                    yield "data: [DONE]\n\n"
                except Exception as e_stream_call:
                    err_msg_detail_stream = f"Streaming Error (Gemini API, model string: '{model_to_call}'): {type(e_stream_call).__name__} - {str(e_stream_call)}"
                    print(f"ERROR: {err_msg_detail_stream}")
                    s_err = str(e_stream_call); s_err = s_err[:1024]+"..." if len(s_err)>1024 else s_err
                    err_resp = create_openai_error_response(500,s_err,"server_error")
                    j_err = json.dumps(err_resp)
                    if not is_auto_attempt: 
                        yield f"data: {j_err}\n\n"
                        yield "data: [DONE]\n\n"
                    raise e_stream_call
            return StreamingResponse(_gemini_real_stream_generator_inner(), media_type="text/event-stream")
    else: # Non-streaming
        response_obj_call = await current_client.aio.models.generate_content(
            model=model_to_call, 
            contents=actual_prompt_for_call,
            config=gen_config_dict # Pass the dictionary directly
        )
        if hasattr(response_obj_call, 'prompt_feedback') and \
           hasattr(response_obj_call.prompt_feedback, 'block_reason') and \
           response_obj_call.prompt_feedback.block_reason:
            block_msg = f"Blocked (Gemini): {response_obj_call.prompt_feedback.block_reason}"
            if hasattr(response_obj_call.prompt_feedback,'block_reason_message') and \
               response_obj_call.prompt_feedback.block_reason_message: 
                block_msg+=f" ({response_obj_call.prompt_feedback.block_reason_message})"
            raise ValueError(block_msg)
        
        if not is_gemini_response_valid(response_obj_call):
            error_details = f"Invalid non-streaming Gemini response for model string '{model_to_call}'. "
            if hasattr(response_obj_call, 'candidates'):
                error_details += f"Candidates: {len(response_obj_call.candidates) if response_obj_call.candidates else 0}. "
                if response_obj_call.candidates and len(response_obj_call.candidates) > 0:
                    candidate = response_obj_call.candidates if isinstance(response_obj_call.candidates, list) else response_obj_call.candidates
                    if hasattr(candidate, 'content'):
                        error_details += "Has content. "
                        if hasattr(candidate.content, 'parts'):
                            error_details += f"Parts: {len(candidate.content.parts) if candidate.content.parts else 0}. "
                            if candidate.content.parts and len(candidate.content.parts) > 0:
                                part = candidate.content.parts if isinstance(candidate.content.parts, list) else candidate.content.parts
                                if hasattr(part, 'text'):
                                    text_preview = str(getattr(part, 'text', ''))[:100]
                                    error_details += f"First part text: '{text_preview}'"
                                elif hasattr(part, 'function_call'):
                                    error_details += f"First part is function_call: {part.function_call.name}"
            else:
                error_details += f"Response type: {type(response_obj_call).__name__}"
            raise ValueError(error_details)
        
        openai_response_content = convert_to_openai_format(response_obj_call, request_obj.model)
        return JSONResponse(content=openai_response_content)