edgequake_llm/providers/

openai.rs

//! OpenAI provider implementation.
//!
//! Supports OpenAI and OpenAI-compatible APIs (Ollama, LM Studio, etc.)

use async_openai::{
    config::OpenAIConfig,
    types::chat::{
        ChatCompletionMessageToolCall, ChatCompletionMessageToolCalls,
        ChatCompletionNamedToolChoice, ChatCompletionRequestAssistantMessageArgs,
        ChatCompletionRequestMessage, ChatCompletionRequestMessageContentPartImage,
        ChatCompletionRequestMessageContentPartText, ChatCompletionRequestSystemMessageArgs,
        ChatCompletionRequestToolMessageArgs, ChatCompletionRequestUserMessageArgs,
        ChatCompletionRequestUserMessageContent, ChatCompletionRequestUserMessageContentPart,
        ChatCompletionStreamOptions, ChatCompletionTool, ChatCompletionToolChoiceOption,
        ChatCompletionTools, CompletionUsage, CreateChatCompletionRequestArgs, FinishReason,
        FunctionCall, FunctionName, FunctionObjectArgs, ImageDetail, ImageUrl, ToolChoiceOptions,
    },
    Client,
};
use async_trait::async_trait;
use futures::StreamExt;
use std::collections::HashMap;
use tracing::debug;

use crate::error::{LlmError, Result};
use crate::traits::FunctionCall as TraitFunctionCall;
use crate::traits::ImageData;
use crate::traits::ToolCall;
use crate::traits::{
    ChatMessage, ChatRole, CompletionOptions, EmbeddingProvider, LLMProvider, LLMResponse,
    StreamChunk, StreamUsage, ToolChoice, ToolDefinition,
};

/// OpenAI provider for text completion and embeddings.
///
/// # Issue #164: Lenient Embedding Deserialization
///
/// Uses a manual HTTP client for embeddings instead of async-openai's strict
/// types. This supports HuggingFace TEI and other OpenAI-compatible servers
/// that omit the cosmetic `object` field in embedding responses.
pub struct OpenAIProvider {
    client: Client<OpenAIConfig>,
    model: String,
    embedding_model: String,
    max_context_length: usize,
    embedding_dimension: usize,
    /// Raw API key for manual HTTP calls (embedding fallback).
    raw_api_key: String,
    /// Base URL for the API (empty = default OpenAI).
    raw_base_url: String,
}

impl OpenAIProvider {
    /// Create a new OpenAI provider with the given API key.
    pub fn new(api_key: impl Into<String>) -> Self {
        let key = api_key.into();
        let config = OpenAIConfig::new().with_api_key(&key);
        Self::with_config_and_key(config, key, String::new())
    }

    /// Create a provider with custom configuration.
    /// Defaults to GPT-5-mini for best balance of performance and cost.
    pub fn with_config(config: OpenAIConfig) -> Self {
        // Extract key/url from config — not directly accessible, so use empty defaults.
        // Callers that need lenient embedding should use with_config_and_key().
        Self::with_config_and_key(config, String::new(), String::new())
    }

    /// Create a provider with custom configuration and explicit key/base_url for embedding fallback.
    fn with_config_and_key(config: OpenAIConfig, api_key: String, base_url: String) -> Self {
        Self {
            client: Client::with_config(config),
            model: "gpt-5-mini".to_string(),
            embedding_model: "text-embedding-3-small".to_string(),
            max_context_length: 200000,
            embedding_dimension: 1536,
            raw_api_key: api_key,
            raw_base_url: base_url,
        }
    }

    /// Create a provider for an OpenAI-compatible API.
    pub fn compatible(api_key: impl Into<String>, base_url: impl Into<String>) -> Self {
        let key = api_key.into();
        let url = base_url.into();
        let config = OpenAIConfig::new().with_api_key(&key).with_api_base(&url);
        Self::with_config_and_key(config, key, url)
    }

    /// Create from environment variables.
    ///
    /// Loads `.env` first (dotenvy). Then reads:
    /// - **Required:** `OPENAI_API_KEY`
    /// - **Optional:** `OPENAI_MODEL` (default: `gpt-5-mini`)
    /// - **Optional:** `OPENAI_BASE_URL` — for compatible APIs
    ///
    /// ```no_run
    /// use edgequake_llm::OpenAIProvider;
    /// let provider = OpenAIProvider::from_env().unwrap();
    /// ```
    pub fn from_env() -> crate::error::Result<Self> {
        let _ = dotenvy::dotenv();
        let api_key = std::env::var("OPENAI_API_KEY")
            .map_err(|_| crate::error::LlmError::ConfigError("OPENAI_API_KEY not set".into()))?;
        let base_url = std::env::var("OPENAI_BASE_URL").unwrap_or_default();
        let mut config = OpenAIConfig::new().with_api_key(&api_key);
        if !base_url.is_empty() {
            config = config.with_api_base(&base_url);
        }
        let mut provider = Self::with_config_and_key(config, api_key, base_url);
        if let Ok(model) = std::env::var("OPENAI_MODEL") {
            provider = provider.with_model(model);
        }
        Ok(provider)
    }

    /// Set the completion model.
    pub fn with_model(mut self, model: impl Into<String>) -> Self {
        self.model = model.into();
        self.max_context_length = Self::context_length_for_model(&self.model);
        self
    }

    /// Set the embedding model.
    pub fn with_embedding_model(mut self, model: impl Into<String>) -> Self {
        self.embedding_model = model.into();
        self.embedding_dimension = Self::dimension_for_model(&self.embedding_model);
        self
    }

    /// Get the context length for a model.
    fn context_length_for_model(model: &str) -> usize {
        match model {
            // GPT-5 series (2026 models)
            m if m.contains("gpt-5.2") || m.contains("gpt-5.1") => 200000,
            m if m.contains("gpt-5-nano") => 128000,
            m if m.contains("gpt-5-mini") || m.contains("gpt-5") => 200000,

            // GPT-4.1 series
            m if m.contains("gpt-4.1") => 128000,

            // O-series reasoning models
            m if m.contains("o4") || m.contains("o3") => 200000,
            m if m.contains("o1") => 200000,

            // GPT-4 series
            m if m.contains("gpt-4o") => 128000,
            m if m.contains("gpt-4-turbo") => 128000,
            m if m.contains("gpt-4-32k") => 32768,
            m if m.contains("gpt-4") => 8192,

            // GPT-3.5 series
            m if m.contains("gpt-3.5-turbo-16k") => 16384,
            m if m.contains("gpt-3.5") => 4096,

            // Codex models
            m if m.contains("codex") => 200000,

            // Realtime and audio models
            m if m.contains("gpt-realtime") || m.contains("gpt-audio") => 128000,

            _ => 128000, // Updated default for newer models
        }
    }

    /// Get the embedding dimension for a model.
    fn dimension_for_model(model: &str) -> usize {
        match model {
            m if m.contains("text-embedding-3-large") => 3072,
            m if m.contains("text-embedding-3-small") => 1536,
            m if m.contains("text-embedding-ada") => 1536,
            _ => 1536, // Default
        }
    }

    fn extract_usage(
        usage: Option<CompletionUsage>,
    ) -> (usize, usize, usize, Option<usize>, Option<usize>) {
        let usage = usage.unwrap_or(CompletionUsage {
            prompt_tokens: 0,
            completion_tokens: 0,
            total_tokens: 0,
            prompt_tokens_details: None,
            completion_tokens_details: None,
        });

        let cache_hit_tokens = usage
            .prompt_tokens_details
            .as_ref()
            .and_then(|d| d.cached_tokens)
            .map(|t| t as usize);
        let thinking_tokens = usage
            .completion_tokens_details
            .as_ref()
            .and_then(|d| d.reasoning_tokens)
            .map(|t| t as usize);

        (
            usage.prompt_tokens as usize,
            usage.completion_tokens as usize,
            usage.total_tokens as usize,
            cache_hit_tokens,
            thinking_tokens,
        )
    }

    fn extract_stream_usage(usage: Option<CompletionUsage>) -> Option<StreamUsage> {
        let (prompt_tokens, completion_tokens, _total_tokens, cache_hit_tokens, thinking_tokens) =
            Self::extract_usage(usage);

        if prompt_tokens == 0
            && completion_tokens == 0
            && cache_hit_tokens.is_none()
            && thinking_tokens.is_none()
        {
            return None;
        }

        let mut usage = StreamUsage::new(prompt_tokens, completion_tokens);
        if let Some(tokens) = cache_hit_tokens {
            usage = usage.with_cache_hit_tokens(tokens);
        }
        if let Some(tokens) = thinking_tokens {
            usage = usage.with_thinking_tokens(tokens);
        }
        Some(usage)
    }

    /// Convert chat messages to OpenAI format.
    ///
    /// Per the OpenAI API spec:
    /// - `system` → `ChatCompletionRequestSystemMessage`
    /// - `user`   → `ChatCompletionRequestUserMessage` (supports multimodal content)
    /// - `assistant` → `ChatCompletionRequestAssistantMessage`; must carry `tool_calls`
    ///   when the model previously requested function calls so the conversation history
    ///   is replayed correctly.
    /// - `tool`   → `ChatCompletionRequestToolMessage` with `tool_call_id`; sending
    ///   tool results as `user` messages is an API contract violation that yields 400.
    /// - `function` → legacy `ChatCompletionRequestFunctionMessage` (deprecated by OpenAI).
    fn convert_messages(messages: &[ChatMessage]) -> Result<Vec<ChatCompletionRequestMessage>> {
        messages
            .iter()
            .map(|msg| {
                match msg.role {
                    ChatRole::System => ChatCompletionRequestSystemMessageArgs::default()
                        .content(msg.content.as_str())
                        .build()
                        .map(Into::into)
                        .map_err(|e| LlmError::InvalidRequest(e.to_string())),

                    ChatRole::User => {
                        let content = Self::build_user_content(msg);
                        ChatCompletionRequestUserMessageArgs::default()
                            .content(content)
                            .build()
                            .map(Into::into)
                            .map_err(|e| LlmError::InvalidRequest(e.to_string()))
                    }

                    ChatRole::Assistant => {
                        let mut builder = ChatCompletionRequestAssistantMessageArgs::default();
                        // Content may be empty when the assistant only emits tool calls.
                        if !msg.content.is_empty() {
                            builder.content(msg.content.clone());
                        }
                        // Propagate tool_calls so the replayed conversation includes
                        // the model's previous function-calling requests.
                        if let Some(ref tool_calls) = msg.tool_calls {
                            let openai_calls: Vec<ChatCompletionMessageToolCalls> = tool_calls
                                .iter()
                                .map(|tc| {
                                    ChatCompletionMessageToolCalls::Function(
                                        ChatCompletionMessageToolCall {
                                            id: tc.id.clone(),
                                            function: FunctionCall {
                                                name: tc.function.name.clone(),
                                                arguments: tc.function.arguments.clone(),
                                            },
                                        },
                                    )
                                })
                                .collect();
                            builder.tool_calls(openai_calls);
                        }
                        builder
                            .build()
                            .map(Into::into)
                            .map_err(|e| LlmError::InvalidRequest(e.to_string()))
                    }

                    ChatRole::Tool => {
                        // The API requires role=tool with the matching tool_call_id.
                        // Sending as a user message loses the correlation identifier and
                        // causes the model to error or misinterpret its own history.
                        let tool_call_id = msg.tool_call_id.clone().ok_or_else(|| {
                            LlmError::InvalidRequest(
                                "Tool message missing required tool_call_id".into(),
                            )
                        })?;
                        ChatCompletionRequestToolMessageArgs::default()
                            .content(msg.content.clone())
                            .tool_call_id(tool_call_id)
                            .build()
                            .map(Into::into)
                            .map_err(|e| LlmError::InvalidRequest(e.to_string()))
                    }

                    ChatRole::Function => {
                        // Deprecated by OpenAI in favour of the `tool` role.
                        // Keep as user message for backward compatibility with older callers.
                        ChatCompletionRequestUserMessageArgs::default()
                            .content(msg.content.as_str())
                            .build()
                            .map(Into::into)
                            .map_err(|e| LlmError::InvalidRequest(e.to_string()))
                    }
                }
            })
            .collect()
    }

    /// Build user message content, supporting multimodal (text + images).
    ///
    /// WHY: Vision-capable OpenAI models (gpt-4o, gpt-4-vision-preview, etc.) require
    /// content to be an array of typed parts when images are present. This function
    /// detects image presence and builds the appropriate content representation.
    fn build_user_content(msg: &ChatMessage) -> ChatCompletionRequestUserMessageContent {
        if msg.has_images() {
            let mut parts: Vec<ChatCompletionRequestUserMessageContentPart> = Vec::new();

            // Add text part first (if non-empty)
            if !msg.content.is_empty() {
                parts.push(ChatCompletionRequestUserMessageContentPart::Text(
                    ChatCompletionRequestMessageContentPartText {
                        text: msg.content.clone(),
                    },
                ));
            }

            // Add image parts
            if let Some(ref images) = msg.images {
                for img in images {
                    let detail = Self::parse_image_detail(img);
                    parts.push(ChatCompletionRequestUserMessageContentPart::ImageUrl(
                        ChatCompletionRequestMessageContentPartImage {
                            image_url: ImageUrl {
                                // Pass URL directly for URL images; wrap base64 in data URI otherwise.
                                url: img.to_api_url(),
                                detail,
                            },
                        },
                    ));
                }
            }

            ChatCompletionRequestUserMessageContent::Array(parts)
        } else {
            ChatCompletionRequestUserMessageContent::Text(msg.content.clone())
        }
    }

    /// Parse image detail level from ImageData.
    fn parse_image_detail(img: &ImageData) -> Option<ImageDetail> {
        match img.detail.as_deref() {
            Some("low") => Some(ImageDetail::Low),
            Some("high") => Some(ImageDetail::High),
            Some("auto") => Some(ImageDetail::Auto),
            _ => None,
        }
    }
}

#[async_trait]
impl LLMProvider for OpenAIProvider {
    fn name(&self) -> &str {
        "openai"
    }

    fn model(&self) -> &str {
        &self.model
    }

    fn max_context_length(&self) -> usize {
        self.max_context_length
    }

    async fn complete(&self, prompt: &str) -> Result<LLMResponse> {
        self.complete_with_options(prompt, &CompletionOptions::default())
            .await
    }

    async fn complete_with_options(
        &self,
        prompt: &str,
        options: &CompletionOptions,
    ) -> Result<LLMResponse> {
        let mut messages = Vec::new();

        if let Some(system) = &options.system_prompt {
            messages.push(ChatMessage::system(system));
        }
        messages.push(ChatMessage::user(prompt));

        self.chat(&messages, Some(options)).await
    }

    async fn chat(
        &self,
        messages: &[ChatMessage],
        options: Option<&CompletionOptions>,
    ) -> Result<LLMResponse> {
        let openai_messages = Self::convert_messages(messages)?;
        let options = options.cloned().unwrap_or_default();

        let mut request_builder = CreateChatCompletionRequestArgs::default();
        request_builder.model(&self.model).messages(openai_messages);

        if let Some(max_tokens) = options.max_tokens {
            // Use max_completion_tokens (the modern, universal parameter).
            // async-openai 0.33 supports this natively for all models including
            // o1/o3/o4 and gpt-4.1 families that previously rejected max_tokens.
            request_builder.max_completion_tokens(max_tokens as u32);
        }

        if let Some(temp) = options.temperature {
            // Bug #15: gpt-4.1-nano, o1, o4-mini only accept the default temperature (1.0).
            // Skip setting temperature when it equals the model default to avoid 400 errors.
            if (temp - 1.0_f32).abs() > f32::EPSILON {
                request_builder.temperature(temp);
            }
        }

        if let Some(top_p) = options.top_p {
            request_builder.top_p(top_p);
        }

        if let Some(stop) = options.stop {
            request_builder.stop(stop);
        }

        if let Some(freq_penalty) = options.frequency_penalty {
            request_builder.frequency_penalty(freq_penalty);
        }

        if let Some(pres_penalty) = options.presence_penalty {
            request_builder.presence_penalty(pres_penalty);
        }

        let request = request_builder
            .build()
            .map_err(|e| LlmError::InvalidRequest(e.to_string()))?;

        let response = self.client.chat().create(request).await?;

        // Debug logging for token tracking
        debug!(
            "OpenAI response - usage: {:?}, model: {}",
            response.usage, response.model
        );

        let choice = response
            .choices
            .first()
            .ok_or_else(|| LlmError::ApiError("No choices in response".to_string()))?;

        // Guardrail: surface content-filter as an explicit error.
        if let Some(FinishReason::ContentFilter) = choice.finish_reason {
            return Err(LlmError::ApiError(
                "Response blocked by OpenAI content filter (finish_reason=content_filter)".into(),
            ));
        }

        let content = choice.message.content.clone().unwrap_or_default();

        let (prompt_tokens, completion_tokens, total_tokens, cache_hit_tokens, thinking_tokens) =
            Self::extract_usage(response.usage.clone());

        // Log extracted token counts
        debug!(
            "OpenAI token usage - prompt: {}, completion: {}, total: {}, cached: {:?}, reasoning: {:?}",
            prompt_tokens, completion_tokens, total_tokens,
            cache_hit_tokens, thinking_tokens
        );

        let mut metadata = HashMap::new();
        metadata.insert("response_id".to_string(), serde_json::json!(response.id));

        Ok(LLMResponse {
            content,
            prompt_tokens,
            completion_tokens,
            total_tokens,
            model: response.model,
            finish_reason: choice.finish_reason.map(|r| format!("{:?}", r)),
            tool_calls: Vec::new(),
            metadata,
            cache_hit_tokens,
            cache_write_tokens: None,
            thinking_tokens,
            thinking_content: None,
        })
    }

    /// Non-streaming chat with tool/function-calling support.
    ///
    /// Implements the full OpenAI tool-use contract:
    /// 1. Sends tools + tool_choice in the request.
    /// 2. Extracts `tool_calls` from the assistant response (if any).
    /// 3. Returns them in `LLMResponse::tool_calls` so the caller can execute
    ///    them and replay the history via `ChatMessage::tool_result(...)`.
    async fn chat_with_tools(
        &self,
        messages: &[ChatMessage],
        tools: &[ToolDefinition],
        tool_choice: Option<ToolChoice>,
        options: Option<&CompletionOptions>,
    ) -> Result<LLMResponse> {
        let openai_messages = Self::convert_messages(messages)?;
        let opts = options.cloned().unwrap_or_default();

        let openai_tools: Vec<ChatCompletionTools> = tools
            .iter()
            .map(|t| {
                ChatCompletionTools::Function(ChatCompletionTool {
                    function: FunctionObjectArgs::default()
                        .name(&t.function.name)
                        .description(&t.function.description)
                        .parameters(t.function.parameters.clone())
                        .build()
                        .expect("Invalid tool definition"),
                })
            })
            .collect();

        let mut request_builder = CreateChatCompletionRequestArgs::default();
        request_builder
            .model(&self.model)
            .messages(openai_messages)
            .tools(openai_tools);

        if let Some(tc) = tool_choice {
            match tc {
                ToolChoice::Auto(_) => {
                    request_builder.tool_choice(ChatCompletionToolChoiceOption::Mode(
                        ToolChoiceOptions::Auto,
                    ));
                }
                ToolChoice::Required(_) => {
                    request_builder.tool_choice(ChatCompletionToolChoiceOption::Mode(
                        ToolChoiceOptions::Required,
                    ));
                }
                ToolChoice::Function { ref function, .. } => {
                    request_builder.tool_choice(ChatCompletionToolChoiceOption::Function(
                        ChatCompletionNamedToolChoice {
                            function: FunctionName {
                                name: function.name.clone(),
                            },
                        },
                    ));
                }
            }
        }

        if let Some(max_tokens) = opts.max_tokens {
            request_builder.max_completion_tokens(max_tokens as u32);
        }

        if let Some(temp) = opts.temperature {
            // Skip temperature=1.0 for strict-mode models (o1/o3/o4) which reject it.
            if (temp - 1.0_f32).abs() > f32::EPSILON {
                request_builder.temperature(temp);
            }
        }

        let request = request_builder
            .build()
            .map_err(|e| LlmError::InvalidRequest(e.to_string()))?;

        let response = self.client.chat().create(request).await?;

        debug!(
            "OpenAI chat_with_tools response id={} model={}",
            response.id, response.model
        );

        let choice = response
            .choices
            .first()
            .ok_or_else(|| LlmError::ApiError("No choices in response".to_string()))?;

        if let Some(FinishReason::ContentFilter) = choice.finish_reason {
            return Err(LlmError::ApiError(
                "Response blocked by OpenAI content filter (finish_reason=content_filter)".into(),
            ));
        }

        // Extract tool calls from the assistant message.
        let tool_calls: Vec<ToolCall> = choice
            .message
            .tool_calls
            .as_deref()
            .unwrap_or_default()
            .iter()
            .filter_map(|tc| {
                if let ChatCompletionMessageToolCalls::Function(f) = tc {
                    Some(ToolCall {
                        id: f.id.clone(),
                        call_type: "function".to_string(),
                        function: TraitFunctionCall {
                            name: f.function.name.clone(),
                            arguments: f.function.arguments.clone(),
                        },
                        thought_signature: None,
                    })
                } else {
                    None
                }
            })
            .collect();

        let content = choice.message.content.clone().unwrap_or_default();

        let (prompt_tokens, completion_tokens, total_tokens, cache_hit_tokens, thinking_tokens) =
            Self::extract_usage(response.usage.clone());

        let mut metadata = HashMap::new();
        metadata.insert("response_id".to_string(), serde_json::json!(response.id));

        Ok(LLMResponse {
            content,
            prompt_tokens,
            completion_tokens,
            total_tokens,
            model: response.model,
            finish_reason: choice.finish_reason.map(|r| format!("{:?}", r)),
            tool_calls,
            metadata,
            cache_hit_tokens,
            cache_write_tokens: None,
            thinking_tokens,
            thinking_content: None,
        })
    }

    fn supports_function_calling(&self) -> bool {
        true
    }

    async fn stream(
        &self,
        prompt: &str,
    ) -> Result<futures::stream::BoxStream<'static, Result<String>>> {
        let request = ChatCompletionRequestUserMessageArgs::default()
            .content(prompt)
            .build()
            .map(Into::into)
            .map_err(|e| LlmError::InvalidRequest(e.to_string()))?;

        let request = CreateChatCompletionRequestArgs::default()
            .model(&self.model)
            .messages(vec![request])
            .stream(true)
            .build()
            .map_err(|e| LlmError::InvalidRequest(e.to_string()))?;

        let stream = self.client.chat().create_stream(request).await?;

        let mapped_stream = stream.map(|res| match res {
            Ok(response) => {
                let content = response
                    .choices
                    .first()
                    .and_then(|c| c.delta.content.clone())
                    .unwrap_or_default();
                Ok(content)
            }
            // IMPORTANT: Use LlmError::from(e) instead of LlmError::ApiError(e.to_string()).
            // e.to_string() uses ApiError's Display which formats as "{type}: {message}"
            // (e.g. "tokens: Rate limit reached..."), masking the structured code/type
            // fields needed for correct RateLimited classification. From<OpenAIError>
            // inspects api_err.code and api_err.message to produce the right variant.
            Err(e) => Err(LlmError::from(e)),
        });

        Ok(mapped_stream.boxed())
    }

    fn supports_streaming(&self) -> bool {
        true
    }

    async fn chat_with_tools_stream(
        &self,
        messages: &[ChatMessage],
        tools: &[ToolDefinition],
        tool_choice: Option<ToolChoice>,
        options: Option<&CompletionOptions>,
    ) -> Result<futures::stream::BoxStream<'static, Result<StreamChunk>>> {
        let openai_messages = Self::convert_messages(messages)?;
        let options = options.cloned().unwrap_or_default();

        // Convert tools to OpenAI 0.33 format.
        // ChatCompletionTools is now an enum: Function(ChatCompletionTool) or Custom(...)
        let openai_tools: Vec<ChatCompletionTools> = tools
            .iter()
            .map(|tool| {
                ChatCompletionTools::Function(ChatCompletionTool {
                    function: FunctionObjectArgs::default()
                        .name(&tool.function.name)
                        .description(&tool.function.description)
                        .parameters(tool.function.parameters.clone())
                        .build()
                        .expect("Invalid tool definition"),
                })
            })
            .collect();

        // Build request
        let mut request_builder = CreateChatCompletionRequestArgs::default();
        request_builder
            .model(&self.model)
            .messages(openai_messages)
            .tools(openai_tools)
            .stream(true)
            .stream_options(ChatCompletionStreamOptions {
                include_usage: Some(true),
                include_obfuscation: None,
            }); // Enable streaming and final usage

        // Set tool choice if specified.
        // In async-openai 0.33, Auto/Required are ChatCompletionToolChoiceOption::Mode(...)
        if let Some(tc) = tool_choice {
            match tc {
                ToolChoice::Auto(_) => {
                    request_builder.tool_choice(ChatCompletionToolChoiceOption::Mode(
                        ToolChoiceOptions::Auto,
                    ));
                }
                ToolChoice::Required(_) => {
                    request_builder.tool_choice(ChatCompletionToolChoiceOption::Mode(
                        ToolChoiceOptions::Required,
                    ));
                }
                ToolChoice::Function { ref function, .. } => {
                    // Force a specific function: {"type":"function","function":{"name":"..."}}
                    request_builder.tool_choice(ChatCompletionToolChoiceOption::Function(
                        ChatCompletionNamedToolChoice {
                            function: FunctionName {
                                name: function.name.clone(),
                            },
                        },
                    ));
                }
            }
        }

        if let Some(temp) = options.temperature {
            // Bug #15: gpt-4.1-nano, o1, o4-mini only accept the default temperature (1.0).
            // Skip setting temperature when it equals the model default to avoid 400 errors.
            if (temp - 1.0_f32).abs() > f32::EPSILON {
                request_builder.temperature(temp);
            }
        }

        if let Some(max_tokens) = options.max_tokens {
            // Use max_completion_tokens (the modern, universal parameter).
            request_builder.max_completion_tokens(max_tokens as u32);
        }

        let request = request_builder
            .build()
            .map_err(|e| LlmError::InvalidRequest(e.to_string()))?;

        let stream = self.client.chat().create_stream(request).await?;

        // Map OpenAI stream to our StreamChunk format
        let mapped_stream = stream.map(|result| {
            match result {
                Ok(response) => {
                    let stream_usage = Self::extract_stream_usage(response.usage.clone());

                    let choice = response.choices.first();
                    if let Some(choice) = choice {
                        // Stream content chunks immediately
                        if let Some(content) = &choice.delta.content {
                            return Ok(StreamChunk::Content(content.clone()));
                        }

                        // Return tool call delta (agent will accumulate)
                        if let Some(tool_call_chunks) = &choice.delta.tool_calls {
                            if let Some(chunk) = tool_call_chunks.first() {
                                return Ok(StreamChunk::ToolCallDelta {
                                    index: chunk.index as usize,
                                    id: chunk.id.clone(),
                                    function_name: chunk
                                        .function
                                        .as_ref()
                                        .and_then(|f| f.name.clone()),
                                    function_arguments: chunk
                                        .function
                                        .as_ref()
                                        .and_then(|f| f.arguments.clone()),
                                    thought_signature: None,
                                });
                            }
                        }

                        // Check finish reason
                        if let Some(finish_reason) = &choice.finish_reason {
                            let reason = match finish_reason {
                                FinishReason::Stop => "stop",
                                FinishReason::Length => "length",
                                FinishReason::ToolCalls => "tool_calls",
                                FinishReason::ContentFilter => "content_filter",
                                FinishReason::FunctionCall => "function_call",
                            };
                            return Ok(StreamChunk::Finished {
                                reason: reason.to_string(),
                                ttft_ms: None,
                                usage: stream_usage,
                            });
                        }
                    }
                    if stream_usage.is_some() {
                        return Ok(StreamChunk::Finished {
                            reason: "stop".to_string(),
                            ttft_ms: None,
                            usage: stream_usage,
                        });
                    }
                    // Empty chunk (no content or tool calls)
                    Ok(StreamChunk::Content(String::new()))
                }
                // IMPORTANT: Propagate through From<OpenAIError> so that rate-limit
                // errors (code: rate_limit_exceeded) are classified as RateLimited,
                // not ApiError. Using e.to_string() loses the structured code field.
                Err(e) => Err(LlmError::from(e)),
            }
        });

        Ok(mapped_stream.boxed())
    }

    fn supports_tool_streaming(&self) -> bool {
        true
    }

    fn supports_json_mode(&self) -> bool {
        // All modern OpenAI chat models support JSON object response format.
        // Exclude only legacy completions models (text-davinci etc).
        let m = &self.model;
        m.contains("gpt-4")
            || m.contains("gpt-3.5-turbo")
            || m.contains("gpt-5")
            || m.starts_with("o1")
            || m.starts_with("o3")
            || m.starts_with("o4")
    }
}

#[async_trait]
impl EmbeddingProvider for OpenAIProvider {
    fn name(&self) -> &str {
        "openai"
    }

    /// Returns the embedding model name (not completion model).
    ///
    /// Note: `model` field refers to completion, `embedding_model` is for embeddings.
    #[allow(clippy::misnamed_getters)]
    fn model(&self) -> &str {
        &self.embedding_model
    }

    fn dimension(&self) -> usize {
        self.embedding_dimension
    }

    fn max_tokens(&self) -> usize {
        8191 // OpenAI embedding models support 8191 tokens
    }

    async fn embed(&self, texts: &[String]) -> Result<Vec<Vec<f32>>> {
        if texts.is_empty() {
            return Ok(Vec::new());
        }

        // Issue #164: Use lenient HTTP-based embedding to support HuggingFace TEI
        // and other OpenAI-compatible servers that omit the cosmetic `object` field.
        let base_url = if self.raw_base_url.is_empty() {
            "https://api.openai.com/v1".to_string()
        } else {
            self.raw_base_url.trim_end_matches('/').to_string()
        };
        let url = format!("{}/embeddings", base_url);

        let request_body = serde_json::json!({
            "model": self.embedding_model,
            "input": texts,
            "encoding_format": "float"
        });

        let http_client = reqwest::Client::new();
        let mut req = http_client.post(&url).json(&request_body);
        if !self.raw_api_key.is_empty() {
            req = req.header("Authorization", format!("Bearer {}", self.raw_api_key));
        }

        let response = req
            .send()
            .await
            .map_err(|e| LlmError::NetworkError(format!("Embedding request failed: {}", e)))?;

        let status = response.status();
        let body = response.text().await.map_err(|e| {
            LlmError::NetworkError(format!("Failed to read embedding response: {}", e))
        })?;

        if !status.is_success() {
            return Err(LlmError::ApiError(format!(
                "Embedding API returned {} {}: {}",
                status.as_u16(),
                status.canonical_reason().unwrap_or(""),
                &body[..body.len().min(500)]
            )));
        }

        // Lenient deserialization: `object` fields are optional (HuggingFace TEI omits them)
        #[derive(serde::Deserialize)]
        struct LenientEmbeddingResponse {
            data: Vec<LenientEmbeddingObject>,
        }
        #[derive(serde::Deserialize)]
        struct LenientEmbeddingObject {
            embedding: Vec<f32>,
        }

        let parsed: LenientEmbeddingResponse = serde_json::from_str(&body).map_err(|e| {
            LlmError::InvalidRequest(format!(
                "Failed to parse embedding response: {} – body: {}",
                e,
                &body[..body.len().min(500)]
            ))
        })?;

        Ok(parsed.data.into_iter().map(|o| o.embedding).collect())
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_context_length_detection() {
        assert_eq!(OpenAIProvider::context_length_for_model("gpt-4o"), 128000);
        assert_eq!(OpenAIProvider::context_length_for_model("gpt-4"), 8192);
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-3.5-turbo"),
            4096
        );
    }

    #[test]
    fn test_embedding_dimension_detection() {
        assert_eq!(
            OpenAIProvider::dimension_for_model("text-embedding-3-large"),
            3072
        );
        assert_eq!(
            OpenAIProvider::dimension_for_model("text-embedding-3-small"),
            1536
        );
    }

    #[test]
    fn test_provider_builder() {
        let provider = OpenAIProvider::new("test-key")
            .with_model("gpt-4")
            .with_embedding_model("text-embedding-3-large");

        assert_eq!(LLMProvider::model(&provider), "gpt-4");
        assert_eq!(provider.dimension(), 3072);
    }

    #[test]
    fn test_message_conversion() {
        let messages = vec![
            ChatMessage::system("You are helpful"),
            ChatMessage::user("Hello"),
            ChatMessage::assistant("Hi there!"),
        ];

        let converted = OpenAIProvider::convert_messages(&messages).unwrap();
        assert_eq!(converted.len(), 3);
    }

    // ---- Iteration 27: Additional OpenAI tests ----

    #[test]
    fn test_context_length_gpt5_series() {
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-5.2-turbo"),
            200000
        );
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-5.1-preview"),
            200000
        );
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-5-nano"),
            128000
        );
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-5-mini"),
            200000
        );
        assert_eq!(OpenAIProvider::context_length_for_model("gpt-5"), 200000);
    }

    #[test]
    fn test_context_length_o_series() {
        assert_eq!(OpenAIProvider::context_length_for_model("o4-mini"), 200000);
        assert_eq!(
            OpenAIProvider::context_length_for_model("o3-preview"),
            200000
        );
        assert_eq!(
            OpenAIProvider::context_length_for_model("o1-preview"),
            200000
        );
    }

    #[test]
    fn test_context_length_gpt4_variants() {
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-4-turbo-preview"),
            128000
        );
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-4-32k-0613"),
            32768
        );
        assert_eq!(OpenAIProvider::context_length_for_model("gpt-4-0613"), 8192);
    }

    #[test]
    fn test_context_length_gpt35_variants() {
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-3.5-turbo-16k"),
            16384
        );
        assert_eq!(
            OpenAIProvider::context_length_for_model("gpt-3.5-turbo-1106"),
            4096
        );
    }

    #[test]
    fn test_context_length_unknown_defaults_high() {
        // Unknown models default to 128K (newer default)
        assert_eq!(
            OpenAIProvider::context_length_for_model("unknown-future-model"),
            128000
        );
    }

    #[test]
    fn test_dimension_ada_model() {
        assert_eq!(
            OpenAIProvider::dimension_for_model("text-embedding-ada-002"),
            1536
        );
    }

    #[test]
    fn test_dimension_unknown_defaults() {
        assert_eq!(
            OpenAIProvider::dimension_for_model("unknown-embedding"),
            1536
        );
    }

    #[test]
    fn test_provider_name() {
        let provider = OpenAIProvider::new("test-key");
        assert_eq!(LLMProvider::name(&provider), "openai");
    }

    #[test]
    fn test_provider_max_context_length() {
        let provider = OpenAIProvider::new("test-key").with_model("gpt-4");
        assert_eq!(provider.max_context_length(), 8192);
    }

    #[test]
    fn test_provider_dimension() {
        let provider =
            OpenAIProvider::new("test-key").with_embedding_model("text-embedding-3-large");
        assert_eq!(provider.dimension(), 3072);
    }

    #[test]
    fn test_provider_embedding_model() {
        let provider =
            OpenAIProvider::new("test-key").with_embedding_model("text-embedding-3-small");
        assert_eq!(
            EmbeddingProvider::model(&provider),
            "text-embedding-3-small"
        );
    }

    #[test]
    fn test_message_conversion_tool_role() {
        // Bug #1 regression: Tool messages must use role=tool + tool_call_id, not role=user.
        let messages = vec![ChatMessage::tool_result("call_abc", "result data")];
        let converted = OpenAIProvider::convert_messages(&messages).unwrap();
        assert_eq!(converted.len(), 1);
        match &converted[0] {
            ChatCompletionRequestMessage::Tool(m) => {
                assert_eq!(m.tool_call_id, "call_abc");
            }
            other => panic!("Expected Tool message, got {:?}", other),
        }
    }

    #[test]
    fn test_tool_message_missing_id_returns_err() {
        let mut msg = ChatMessage::user("orphan");
        msg.role = ChatRole::Tool;
        msg.tool_call_id = None;
        let r = OpenAIProvider::convert_messages(&[msg]);
        assert!(
            r.is_err(),
            "Expected Err for tool message without tool_call_id"
        );
    }

    #[test]
    fn test_assistant_with_tool_calls_serialized() {
        // Bug #2 regression: assistant tool_calls must be propagated.
        let calls = vec![ToolCall {
            id: "call_xyz".to_string(),
            call_type: "function".to_string(),
            function: TraitFunctionCall {
                name: "get_weather".to_string(),
                arguments: r#"{"city":"Paris"}"#.to_string(),
            },
            thought_signature: None,
        }];
        let msg = ChatMessage::assistant_with_tools("", calls);
        let converted = OpenAIProvider::convert_messages(&[msg]).unwrap();
        assert_eq!(converted.len(), 1);
        match &converted[0] {
            ChatCompletionRequestMessage::Assistant(m) => {
                let tcs = m.tool_calls.as_ref().expect("tool_calls must be present");
                assert_eq!(tcs.len(), 1);
                if let ChatCompletionMessageToolCalls::Function(f) = &tcs[0] {
                    assert_eq!(f.id, "call_xyz");
                    assert_eq!(f.function.name, "get_weather");
                } else {
                    panic!("Expected Function tool call");
                }
            }
            other => panic!("Expected Assistant message, got {:?}", other),
        }
    }

    #[test]
    fn test_supports_streaming() {
        let provider = OpenAIProvider::new("test-key");
        assert!(provider.supports_streaming());
    }

    #[test]
    fn test_supports_json_mode_gpt4() {
        let provider = OpenAIProvider::new("test-key").with_model("gpt-4o");
        assert!(provider.supports_json_mode());
    }

    #[test]
    fn test_supports_json_mode_gpt35() {
        let provider = OpenAIProvider::new("test-key").with_model("gpt-3.5-turbo");
        assert!(provider.supports_json_mode());
    }

    #[test]
    fn test_supports_json_mode_default_is_false() {
        // Old completion-only models do not support JSON mode
        let provider = OpenAIProvider::new("test-key").with_model("davinci-002");
        assert!(!provider.supports_json_mode());
    }

    // ---- Vision / multimodal message tests ----

    #[test]
    fn test_build_user_content_text_only() {
        let msg = ChatMessage::user("Hello");
        let content = OpenAIProvider::build_user_content(&msg);
        match content {
            ChatCompletionRequestUserMessageContent::Text(t) => assert_eq!(t, "Hello"),
            _ => panic!("Expected text content"),
        }
    }

    #[test]
    fn test_build_user_content_with_image() {
        use crate::traits::ImageData;
        let img = ImageData::new("base64data", "image/png");
        let msg = ChatMessage::user_with_images("Describe this", vec![img]);
        let content = OpenAIProvider::build_user_content(&msg);
        match content {
            ChatCompletionRequestUserMessageContent::Array(parts) => {
                assert_eq!(parts.len(), 2, "Should have text + image parts");
                assert!(
                    matches!(
                        parts[0],
                        ChatCompletionRequestUserMessageContentPart::Text(_)
                    ),
                    "First part should be text"
                );
                assert!(
                    matches!(
                        parts[1],
                        ChatCompletionRequestUserMessageContentPart::ImageUrl(_)
                    ),
                    "Second part should be image_url"
                );
            }
            _ => panic!("Expected array content for vision message"),
        }
    }

    #[test]
    fn test_build_user_content_image_data_uri() {
        use crate::traits::ImageData;
        let img = ImageData::new("abc123", "image/jpeg");
        let msg = ChatMessage::user_with_images("What's here?", vec![img]);
        let content = OpenAIProvider::build_user_content(&msg);
        if let ChatCompletionRequestUserMessageContent::Array(parts) = content {
            if let ChatCompletionRequestUserMessageContentPart::ImageUrl(img_part) = &parts[1] {
                assert_eq!(
                    img_part.image_url.url, "data:image/jpeg;base64,abc123",
                    "Data URI should be correct"
                );
            } else {
                panic!("Expected ImageUrl part");
            }
        } else {
            panic!("Expected array content");
        }
    }

    #[test]
    fn test_build_user_content_image_with_detail() {
        use crate::traits::ImageData;
        let img = ImageData::new("data", "image/png").with_detail("high");
        let _msg = ChatMessage::user_with_images("Analyze", vec![img]);
        let detail = OpenAIProvider::parse_image_detail(
            &ImageData::new("x", "image/png").with_detail("high"),
        );
        assert!(matches!(detail, Some(ImageDetail::High)));
    }

    #[test]
    fn test_parse_image_detail_low() {
        use crate::traits::ImageData;
        let img = ImageData::new("x", "image/png").with_detail("low");
        let d = OpenAIProvider::parse_image_detail(&img);
        assert!(matches!(d, Some(ImageDetail::Low)));
    }

    #[test]
    fn test_parse_image_detail_auto() {
        use crate::traits::ImageData;
        let img = ImageData::new("x", "image/png").with_detail("auto");
        let d = OpenAIProvider::parse_image_detail(&img);
        assert!(matches!(d, Some(ImageDetail::Auto)));
    }

    #[test]
    fn test_parse_image_detail_none() {
        use crate::traits::ImageData;
        let img = ImageData::new("x", "image/png");
        let d = OpenAIProvider::parse_image_detail(&img);
        assert!(d.is_none());
    }

    #[test]
    fn test_convert_messages_with_image_produces_array_content() {
        use crate::traits::ImageData;
        let img = ImageData::new("iVBORw0KGgo", "image/png");
        let messages = vec![
            ChatMessage::system("You are a vision assistant"),
            ChatMessage::user_with_images("What is in this image?", vec![img]),
        ];
        let converted = OpenAIProvider::convert_messages(&messages).unwrap();
        assert_eq!(converted.len(), 2);
        // Verify the user message is a ChatCompletionRequestMessage::User with Array content
        // We can validate via JSON serialization
        let json = serde_json::to_value(&converted[1]).unwrap();
        let content = &json["content"];
        assert!(
            content.is_array(),
            "Vision user message content must be a JSON array, got: {:?}",
            content
        );
        let parts = content.as_array().unwrap();
        assert_eq!(parts.len(), 2, "Should have text + image parts");
        assert_eq!(parts[0]["type"], "text");
        assert_eq!(parts[1]["type"], "image_url");
        assert!(parts[1]["image_url"]["url"]
            .as_str()
            .unwrap()
            .starts_with("data:image/png;base64,"));
    }

    #[test]
    fn test_convert_messages_without_image_produces_text_content() {
        let messages = vec![ChatMessage::user("Just text")];
        let converted = OpenAIProvider::convert_messages(&messages).unwrap();
        let json = serde_json::to_value(&converted[0]).unwrap();
        let content = &json["content"];
        assert!(
            content.is_string(),
            "Plain text user message content must be a JSON string"
        );
        assert_eq!(content.as_str().unwrap(), "Just text");
    }

    // ---- async-openai 0.33 upgrade tests ----

    /// Test that tools are correctly wrapped in ChatCompletionTools::Function.
    /// In 0.33, the tools parameter takes Vec<ChatCompletionTools> (enum) not
    /// Vec<ChatCompletionTool> (struct).
    #[test]
    fn test_chat_completion_tools_function_wrapping() {
        use crate::traits::FunctionDefinition;
        let tool_def = ToolDefinition {
            tool_type: "function".to_string(),
            function: FunctionDefinition {
                name: "get_weather".to_string(),
                description: "Get the current weather".to_string(),
                parameters: serde_json::json!({
                    "type": "object",
                    "properties": {
                        "location": { "type": "string" }
                    },
                    "required": ["location"]
                }),
                strict: None,
            },
        };

        // Build the tool using the new 0.33 pattern
        let openai_tool = ChatCompletionTools::Function(ChatCompletionTool {
            function: FunctionObjectArgs::default()
                .name(&tool_def.function.name)
                .description(&tool_def.function.description)
                .parameters(tool_def.function.parameters.clone())
                .build()
                .unwrap(),
        });

        // Verify it serializes correctly
        let json = serde_json::to_value(&openai_tool).unwrap();
        assert_eq!(json["type"], "function");
        assert_eq!(json["function"]["name"], "get_weather");
        assert_eq!(json["function"]["description"], "Get the current weather");
    }

    /// Test that ToolChoiceOptions::Auto/Required serialize correctly.
    /// In 0.33, these are behind ChatCompletionToolChoiceOption::Mode(...)
    #[test]
    fn test_tool_choice_auto_serialization() {
        let choice = ChatCompletionToolChoiceOption::Mode(ToolChoiceOptions::Auto);
        let json = serde_json::to_value(&choice).unwrap();
        assert_eq!(json, "auto");
    }

    #[test]
    fn test_tool_choice_required_serialization() {
        let choice = ChatCompletionToolChoiceOption::Mode(ToolChoiceOptions::Required);
        let json = serde_json::to_value(&choice).unwrap();
        assert_eq!(json, "required");
    }

    #[test]
    fn test_tool_choice_none_serialization() {
        let choice = ChatCompletionToolChoiceOption::Mode(ToolChoiceOptions::None);
        let json = serde_json::to_value(&choice).unwrap();
        assert_eq!(json, "none");
    }

    /// Test that max_completion_tokens is correctly serialized in the request.
    /// This verifies the fix for issue #13 — models like o1/o3/o4 and gpt-4.1
    /// require max_completion_tokens, not the deprecated max_tokens.
    #[test]
    fn test_max_completion_tokens_in_request_serialization() {
        let request = CreateChatCompletionRequestArgs::default()
            .model("o3-mini")
            .messages(vec![ChatCompletionRequestUserMessageArgs::default()
                .content("Hello")
                .build()
                .unwrap()
                .into()])
            .max_completion_tokens(1024u32)
            .build()
            .unwrap();

        let json = serde_json::to_value(&request).unwrap();
        assert_eq!(
            json["max_completion_tokens"], 1024,
            "max_completion_tokens should be set in request"
        );
        assert!(
            json["max_tokens"].is_null(),
            "deprecated max_tokens should NOT be set"
        );
    }

    /// Test that max_completion_tokens works for legacy models too.
    /// In 0.33, all models accept max_completion_tokens — old max_tokens is deprecated.
    #[test]
    fn test_max_completion_tokens_works_for_all_models() {
        for model in &[
            "gpt-4o",
            "gpt-3.5-turbo",
            "o1-preview",
            "o3-mini",
            "gpt-4.1-nano",
        ] {
            let request = CreateChatCompletionRequestArgs::default()
                .model(*model)
                .messages(vec![ChatCompletionRequestUserMessageArgs::default()
                    .content("Test")
                    .build()
                    .unwrap()
                    .into()])
                .max_completion_tokens(512u32)
                .build()
                .unwrap();

            let json = serde_json::to_value(&request).unwrap();
            assert_eq!(
                json["max_completion_tokens"], 512,
                "max_completion_tokens should be set for model {}",
                model
            );
        }
    }

    /// Test cache hit token extraction from PromptTokensDetails.
    /// This validates the new async-openai 0.33 feature used in chat() method.
    #[test]
    fn test_cache_hit_token_extraction() {
        use async_openai::types::chat::PromptTokensDetails;

        let usage = CompletionUsage {
            prompt_tokens: 100,
            completion_tokens: 50,
            total_tokens: 150,
            prompt_tokens_details: Some(PromptTokensDetails {
                cached_tokens: Some(80),
                audio_tokens: None,
            }),
            completion_tokens_details: None,
        };

        let cache_hit_tokens = usage
            .prompt_tokens_details
            .as_ref()
            .and_then(|d| d.cached_tokens)
            .map(|t| t as usize);

        assert_eq!(cache_hit_tokens, Some(80));
    }

    /// Test reasoning token extraction from CompletionTokensDetails.
    /// This validates the new async-openai 0.33 feature for o-series models.
    #[test]
    fn test_reasoning_token_extraction() {
        use async_openai::types::chat::CompletionTokensDetails;

        let usage = CompletionUsage {
            prompt_tokens: 50,
            completion_tokens: 200,
            total_tokens: 250,
            prompt_tokens_details: None,
            completion_tokens_details: Some(CompletionTokensDetails {
                reasoning_tokens: Some(150),
                audio_tokens: None,
                accepted_prediction_tokens: None,
                rejected_prediction_tokens: None,
            }),
        };

        let thinking_tokens = usage
            .completion_tokens_details
            .as_ref()
            .and_then(|d| d.reasoning_tokens)
            .map(|t| t as usize);

        assert_eq!(thinking_tokens, Some(150));
    }

    /// Test that missing token details returns None (no panic).
    #[test]
    fn test_token_details_none_is_safe() {
        let usage = CompletionUsage {
            prompt_tokens: 10,
            completion_tokens: 20,
            total_tokens: 30,
            prompt_tokens_details: None,
            completion_tokens_details: None,
        };

        let cache_hit = usage
            .prompt_tokens_details
            .as_ref()
            .and_then(|d| d.cached_tokens)
            .map(|t| t as usize);

        let reasoning = usage
            .completion_tokens_details
            .as_ref()
            .and_then(|d| d.reasoning_tokens)
            .map(|t| t as usize);

        assert_eq!(cache_hit, None);
        assert_eq!(reasoning, None);
    }

    /// Test that FinishReason variants still exist and format correctly.
    /// Validates no regression in finish reason handling after 0.33 upgrade.
    #[test]
    fn test_finish_reason_variants() {
        let cases = vec![
            (FinishReason::Stop, "Stop"),
            (FinishReason::Length, "Length"),
            (FinishReason::ToolCalls, "ToolCalls"),
            (FinishReason::ContentFilter, "ContentFilter"),
            (FinishReason::FunctionCall, "FunctionCall"),
        ];

        for (reason, expected_debug) in cases {
            let formatted = format!("{:?}", reason);
            assert_eq!(
                formatted, expected_debug,
                "FinishReason::{} should format as {:?}",
                expected_debug, expected_debug
            );
        }
    }

    /// Test OpenAIError::JSONDeserialize now takes 2 args in 0.33.
    /// Validates that our error conversion handles the new signature.
    #[test]
    fn test_json_deserialize_error_conversion() {
        use crate::error::LlmError;
        // Simulate the 2-arg variant matching
        let serde_err = serde_json::from_str::<serde_json::Value>("invalid json {{").unwrap_err();
        let openai_err = async_openai::error::OpenAIError::JSONDeserialize(
            serde_err,
            "invalid json {{".to_string(),
        );
        let llm_err = LlmError::from(openai_err);
        assert!(
            matches!(llm_err, LlmError::SerializationError(_)),
            "JSONDeserialize error should convert to SerializationError"
        );
    }

    /// Test that ChatCompletionTool no longer has a type field in 0.33.
    /// In 0.24 it had `r#type: ChatCompletionToolType::Function` but
    /// in 0.33 the type is encoded in the ChatCompletionTools enum variant.
    #[test]
    fn test_chat_completion_tool_serialization() {
        let tool = ChatCompletionTool {
            function: FunctionObjectArgs::default()
                .name("my_func")
                .description("A test function")
                .parameters(serde_json::json!({"type": "object"}))
                .build()
                .unwrap(),
        };
        let wrapped = ChatCompletionTools::Function(tool);
        let json = serde_json::to_value(&wrapped).unwrap();

        // In 0.33, type is determined by the enum variant tag
        assert_eq!(json["type"], "function");
        assert_eq!(json["function"]["name"], "my_func");
    }
}