use crate::agent::context_compressor::estimate_tokens;
use crate::agent::media_handler::MediaHandlerRegistry;
use crate::agent::system_prompt::build_system_prompt;
use crate::bus::message::ContentBlock;
use crate::bus::{ChatMessage, MediaRef};
use crate::config::LLMProviderConfig;
use crate::observability::{
    truncate_args, Observer, ObserverEvent, ToolExecutionOutcome,
};
use crate::providers::{create_provider, LLMProvider, ChatCompletionRequest, Message, ToolCall};
use crate::tools::ToolRegistry;
use std::collections::VecDeque;
use std::hash::{Hash, Hasher};
use std::path::PathBuf;
use std::sync::Arc;
use std::time::Instant;

/// Maximum characters in a tool result before truncation.
/// Prevents context overflow from large tool outputs.
const MAX_TOOL_RESULT_CHARS: usize = 16_000;
/// Minimum characters to keep when truncating
const TRUNCATION_SUFFIX_LEN: usize = 200;

/// Build content blocks from text and media, respecting model input capabilities
fn build_content_blocks(
    text: &str,
    media_refs: &[MediaRef],
    input_types: &[String],
    registry: &MediaHandlerRegistry,
) -> Vec<ContentBlock> {
    let mut blocks = Vec::new();

    if !media_refs.is_empty() {
        for mr in media_refs {
            if input_types.contains(&mr.media_type) {
                match registry.handle(&mr.media_type, &mr.path) {
                    Ok(content_blocks) => blocks.extend(content_blocks),
                    Err(e) => {
                        tracing::warn!(
                            path = %mr.path,
                            media_type = %mr.media_type,
                            error = %e,
                            "Media handler failed, falling back to text placeholder"
                        );
                        blocks.push(ContentBlock::text(format!(
                            "[用户发来了一个文件，但处理失败: {}, 错误: {}]",
                            mr.path, e
                        )));
                    }
                }
            } else {
                tracing::debug!(
                    path = %mr.path,
                    media_type = %mr.media_type,
                    model_input_types = ?input_types,
                    "Media type not supported by model, using text placeholder"
                );
                blocks.push(ContentBlock::text(format!(
                    "[用户发来了一个文件: {}]",
                    mr.path
                )));
            }
        }
    } else if !text.is_empty() {
        blocks.push(ContentBlock::text(text));
    }

    if blocks.is_empty() {
        blocks.push(ContentBlock::text(""));
    }

    blocks
}

/// Truncate tool result if it exceeds MAX_TOOL_RESULT_CHARS.
/// Preserves the end of the output as it often contains the conclusion/useful result.
fn truncate_tool_result(output: &str) -> String {
    if output.len() <= MAX_TOOL_RESULT_CHARS {
        return output.to_string();
    }

    let truncated_start_len = output.len().saturating_sub(TRUNCATION_SUFFIX_LEN);
    if truncated_start_len > MAX_TOOL_RESULT_CHARS {
        // Even after removing suffix, still too long - take from beginning
        format!(
            "{}...\n\n[Output truncated - {} characters removed]",
            &output[..output.ceil_char_boundary(MAX_TOOL_RESULT_CHARS - 100)],
            output.len() - MAX_TOOL_RESULT_CHARS + 100
        )
    } else {
        // Keep most of the end which usually contains the useful result
        format!(
            "...\n\n[Output truncated - {} characters removed]\n\n{}",
            truncated_start_len,
            &output[output.floor_char_boundary(truncated_start_len)..]
        )
    }
}

/// Loop detection result.
#[derive(Debug, Clone, PartialEq, Eq)]
enum LoopDetectionResult {
    /// No warning needed.
    Ok,
    /// Warning: same tool + args repeated N times.
    Warning(String),
}

/// Configuration for loop detector.
#[derive(Debug, Clone)]
struct LoopDetectorConfig {
    /// Master switch.
    enabled: bool,
    /// Warn every N consecutive identical calls.
    warn_every: usize,
}

impl Default for LoopDetectorConfig {
    fn default() -> Self {
        Self {
            enabled: true,
            warn_every: 5,
        }
    }
}

/// A single recorded tool invocation in the sliding window.
#[derive(Debug, Clone)]
struct ToolCallRecord {
    name: String,
    args_hash: u64,
}

/// Stateful loop detector that monitors for repetitive patterns.
struct LoopDetector {
    config: LoopDetectorConfig,
    window: VecDeque<ToolCallRecord>,
}

impl LoopDetector {
    fn new(config: LoopDetectorConfig) -> Self {
        Self {
            window: VecDeque::with_capacity(config.warn_every * 2),
            config,
        }
    }

    /// Record a completed tool call and check for loop patterns.
    /// Returns Warning every `warn_every` consecutive identical calls.
    fn record(&mut self, name: &str, args: &serde_json::Value) -> LoopDetectionResult {
        if !self.config.enabled {
            return LoopDetectionResult::Ok;
        }

        let record = ToolCallRecord {
            name: name.to_string(),
            args_hash: hash_json_value(args),
        };

        // Maintain sliding window
        if self.window.len() >= self.config.warn_every * 2 {
            self.window.pop_front();
        }
        self.window.push_back(record);

        // Count consecutive identical calls
        let last = self.window.back().unwrap();
        let consecutive: usize = self
            .window
            .iter()
            .rev()
            .take_while(|r| r.name == last.name && r.args_hash == last.args_hash)
            .count();

        // Warn every warn_every times
        if consecutive > 0 && consecutive.is_multiple_of(self.config.warn_every) {
            LoopDetectionResult::Warning(format!(
                "注意: 工具 '{}' 已连续执行 {} 次，参数相同。如果任务没有进展，请尝试其他方法。",
                last.name, consecutive
            ))
        } else {
            LoopDetectionResult::Ok
        }
    }
}

/// Hash a JSON value deterministically (key-order independent).
fn hash_json_value(value: &serde_json::Value) -> u64 {
    let mut hasher = std::collections::hash_map::DefaultHasher::new();
    let canonical = canonicalise_json(value);
    canonical.hash(&mut hasher);
    hasher.finish()
}

/// Return a clone of value with all object keys sorted recursively.
fn canonicalise_json(value: &serde_json::Value) -> serde_json::Value {
    match value {
        serde_json::Value::Object(map) => {
            let mut sorted: Vec<(&String, &serde_json::Value)> = map.iter().collect();
            sorted.sort_by_key(|(k, _)| *k);
            let new_map: serde_json::Map<String, serde_json::Value> = sorted
                .into_iter()
                .map(|(k, v)| (k.clone(), canonicalise_json(v)))
                .collect();
            serde_json::Value::Object(new_map)
        }
        serde_json::Value::Array(arr) => {
            serde_json::Value::Array(arr.iter().map(canonicalise_json).collect())
        }
        other => other.clone(),
    }
}
/// AgentLoop - Stateless agent that processes messages with tool calling support.
/// History is managed externally by SessionManager.
pub struct AgentLoop {
    provider: Arc<dyn LLMProvider>,
    tools: Arc<ToolRegistry>,
    observer: Option<Arc<dyn Observer>>,
    max_iterations: usize,
    workspace_dir: PathBuf,
    model_name: String,
    context_window: usize,
    notify_tx: Option<tokio::sync::mpsc::UnboundedSender<String>>,
    input_types: Vec<String>,
    media_registry: MediaHandlerRegistry,
}
#[derive(Debug, Clone)]
pub struct AgentProcessResult {
    pub final_response: ChatMessage,
    pub emitted_messages: Vec<ChatMessage>,
}

impl AgentLoop {
    /// Create a new AgentLoop with a provider created from config.
    pub fn new(provider_config: LLMProviderConfig) -> Result<Self, AgentError> {
        let max_iterations = provider_config.max_tool_iterations;
        let model_name = provider_config.model_id.clone();
        let workspace_dir = provider_config.workspace_dir.clone();
        let input_types = provider_config.input_types.clone();
        let provider = create_provider(provider_config)
            .map_err(|e| AgentError::ProviderCreation(e.to_string()))?;

        Ok(Self {
            provider: Arc::from(provider),
            tools: Arc::new(ToolRegistry::new()),
            observer: None,
            notify_tx: None,
            context_window: 0,
            max_iterations,
            workspace_dir,
            model_name,
            input_types,
            media_registry: MediaHandlerRegistry::with_defaults(),
        })
    }

    /// Create a new AgentLoop with provider created from config and given tools.
    pub fn with_tools(provider_config: LLMProviderConfig, tools: Arc<ToolRegistry>) -> Result<Self, AgentError> {
        let max_iterations = provider_config.max_tool_iterations;
        let model_name = provider_config.model_id.clone();
        let workspace_dir = provider_config.workspace_dir.clone();
        let input_types = provider_config.input_types.clone();
        let provider = create_provider(provider_config)
            .map_err(|e| AgentError::ProviderCreation(e.to_string()))?;

        Ok(Self {
            provider: Arc::from(provider),
            tools,
            observer: None,
            notify_tx: None,
            context_window: 0,
            max_iterations,
            workspace_dir,
            model_name,
            input_types,
            media_registry: MediaHandlerRegistry::with_defaults(),
        })
    }

    /// Create a new AgentLoop with an existing shared provider.
    pub fn with_provider(provider: Arc<dyn LLMProvider>, max_iterations: usize, model_name: String, workspace_dir: PathBuf, input_types: Vec<String>) -> Self {
        Self {
            provider,
            tools: Arc::new(ToolRegistry::new()),
            observer: None,
            notify_tx: None,
            context_window: 0,
            max_iterations,
            workspace_dir,
            model_name,
            input_types,
            media_registry: MediaHandlerRegistry::with_defaults(),
        }
    }

    /// Create a new AgentLoop with an existing shared provider and given tools.
    pub fn with_provider_and_tools(
        provider: Arc<dyn LLMProvider>,
        tools: Arc<ToolRegistry>,
        max_iterations: usize,
        model_name: String,
        workspace_dir: PathBuf,
        input_types: Vec<String>,
    ) -> Self {
        Self {
            provider,
            tools,
            observer: None,
            notify_tx: None,
            context_window: 0,
            max_iterations,
            workspace_dir,
            model_name,
            input_types,
            media_registry: MediaHandlerRegistry::with_defaults(),
        }
    }

    /// Set the context window size for preemptive trimming.
    pub fn with_context_window(mut self, window: usize) -> Self {
        self.context_window = window;
        self
    }

    /// Set the workspace directory.
    pub fn with_workspace_dir(mut self, dir: PathBuf) -> Self {
        self.workspace_dir = dir;
        self
    }

    /// Set an observer for tracking events.
    pub fn with_observer(mut self, observer: Arc<dyn Observer>) -> Self {
        self.observer = Some(observer);
        self
    }

    pub fn with_notify(mut self, tx: tokio::sync::mpsc::UnboundedSender<String>) -> Self {
        self.notify_tx = Some(tx);
        self
    }

    /// Preemptive trim: truncate old tool results in-place when history is
    /// approaching the context window limit. Only trims tool messages with
    /// content > TRIM_CHARS, preserving the most recent KEEP messages.
    fn preemptive_trim_old_tool_results(
        &self,
        messages: &mut [ChatMessage],
        max_chars: usize,
        keep_recent: usize,
    ) -> usize {
        let end = messages.len().saturating_sub(keep_recent);
        let start = 1; // protect system message at [0] if present
        let mut modified = 0;
        for i in start..end {
            if messages[i].role != "tool" {
                continue;
            }
            if messages[i].content.len() <= max_chars {
                continue;
            }
            let removed = messages[i].content.len() - max_chars;
            messages[i].content = format!(
                "{}...\n\n[Output truncated - {} characters removed]",
                &messages[i].content[..messages[i].content.ceil_char_boundary(max_chars)],
                removed
            );
            modified += 1;
        }
        modified
    }

    pub fn tools(&self) -> &Arc<ToolRegistry> {
        &self.tools
    }

    fn chat_message_to_llm_message(&self, m: &ChatMessage) -> Message {
        let content = if m.media_refs.is_empty() {
            vec![ContentBlock::text(&m.content)]
        } else {
            build_content_blocks(&m.content, &m.media_refs, &self.input_types, &self.media_registry)
        };

        Message {
            role: m.role.clone(),
            content,
            tool_call_id: m.tool_call_id.clone(),
            name: m.tool_name.clone(),
            tool_calls: m.tool_calls.clone(),
        }
    }

    /// Process a message using the provided conversation history.
    /// History management is handled externally by SessionManager.
    ///
    /// This method supports multi-round tool calling: after executing tools,
    /// it loops back to the LLM with the tool results until either:
    /// - The LLM returns no more tool calls (final response)
    /// - Maximum iterations are reached
    pub async fn process(&self, mut messages: Vec<ChatMessage>) -> Result<AgentProcessResult, AgentError> {
        #[cfg(debug_assertions)]
        tracing::debug!(history_len = messages.len(), max_iterations = self.max_iterations, "Starting agent process");

        // Build and inject system prompt if not present
        let has_system = messages.first().is_some_and(|m| m.role == "system");
        if !has_system {
            let system_prompt = build_system_prompt(&self.workspace_dir, &self.model_name, &self.tools, None, None, false);
            #[cfg(debug_assertions)]
            tracing::debug!("System prompt injected:\n{}", system_prompt);
            messages.insert(0, ChatMessage::system(system_prompt));
        }

        // Track tool calls for loop detection
        let mut loop_detector = LoopDetector::new(LoopDetectorConfig::default());
        let mut emitted_messages = Vec::new();

        for iteration in 0..self.max_iterations {
            #[cfg(debug_assertions)]
            tracing::debug!(iteration, "Agent iteration started");

            // Preemptive context check: trim old tool results if token estimate
            // exceeds 80% of context window to prevent mid-loop overflow.
            if self.context_window > 0 {
                let estimated = estimate_tokens(&messages);
                let danger = (self.context_window as f64 * 0.8) as usize;
                if estimated > danger {
                    let trimmed = self.preemptive_trim_old_tool_results(
                        &mut messages, 2000, 4,
                    );
                    if trimmed > 0 {
                        #[cfg(debug_assertions)]
                        tracing::debug!(
                            estimated,
                            danger,
                            trimmed_msgs = trimmed,
                            "Preemptive tool-result trim applied in loop"
                        );
                    }
                }
            }

            // Convert messages to LLM format
            let messages_for_llm: Vec<Message> = messages
                .iter()
                .map(|m| self.chat_message_to_llm_message(m))
                .collect();

            // Build request
            let tools = if self.tools.has_tools() {
                Some(self.tools.get_definitions())
            } else {
                None
            };

            let request = ChatCompletionRequest {
                messages: messages_for_llm,
                temperature: None,
                max_tokens: None,
                tools,
            };

            // Call LLM
            let response = (*self.provider).chat(request).await
                .map_err(|e| {
                    tracing::error!(error = %e, "LLM request failed");
                    AgentError::LlmError(e.to_string())
                })?;

            #[cfg(debug_assertions)]
            tracing::debug!(
                iteration,
                response_len = response.content.len(),
                tool_calls_len = response.tool_calls.len(),
                "LLM response received"
            );

            // If no tool calls, this is the final response
            if response.tool_calls.is_empty() {
                let assistant_message = ChatMessage::assistant(response.content);
                emitted_messages.push(assistant_message.clone());
                return Ok(AgentProcessResult {
                    final_response: assistant_message,
                    emitted_messages,
                });
            }

            // Execute tool calls — log and notify immediately
            {
                let tools_info: Vec<String> = response.tool_calls.iter()
                    .map(|tc| {
                        let args = serde_json::to_string(&tc.arguments).unwrap_or_default();
                        let s = format!("{}:{}", tc.name, args);
                        if let Some(ref tx) = self.notify_tx {
                            let _ = tx.send(format!("调用工具 {}", s));
                        }
                        s
                    })
                    .collect();
                tracing::info!(iteration, count = response.tool_calls.len(), tools = %tools_info.join(", "), "Tool calls detected, executing tools");
            }

            // Add assistant message with tool calls
            let assistant_message = ChatMessage::assistant_with_tool_calls(
                response.content.clone(),
                response.tool_calls.clone(),
            );
            messages.push(assistant_message.clone());
            emitted_messages.push(assistant_message);

            // Execute tools and add results to messages
            let tool_results = self.execute_tools(&response.tool_calls).await;

            for (tool_call, result) in response.tool_calls.iter().zip(tool_results.iter()) {
                // Log function call with name and arguments
                let args_str = match &tool_call.arguments {
                    serde_json::Value::Object(obj) if obj.is_empty() => "{}".to_string(),
                    other => serde_json::to_string_pretty(other).unwrap_or_else(|_| other.to_string()),
                };
                tracing::info!(tool = %tool_call.name, args = %args_str, "Calling tool");

                // Truncate tool result if too large
                let truncated_output = truncate_tool_result(&result.output);

                // Record tool call and check for loops
                let loop_result = loop_detector.record(&tool_call.name, &tool_call.arguments);

                match loop_result {
                    LoopDetectionResult::Warning(msg) => {
                        // Add warning and proceed
                        tracing::warn!(
                            tool = %tool_call.name,
                            "Loop warning: {}",
                            msg
                        );
                        let tool_message = ChatMessage::tool(
                            tool_call.id.clone(),
                            tool_call.name.clone(),
                            format!("{}\n\n[上一条结果]\n{}", msg, truncated_output),
                        );
                        messages.push(tool_message.clone());
                        emitted_messages.push(tool_message);
                    }
                    LoopDetectionResult::Ok => {
                        let tool_message = ChatMessage::tool(
                            tool_call.id.clone(),
                            tool_call.name.clone(),
                            truncated_output,
                        );
                        messages.push(tool_message.clone());
                        emitted_messages.push(tool_message);
                    }
                }
            }

            // Loop continues to next iteration with updated messages
            #[cfg(debug_assertions)]
            tracing::debug!(iteration, message_count = messages.len(), "Tool execution complete, continuing to next iteration");
        }

        // Max iterations reached - ask LLM for a summary based on completed work
        tracing::warn!("Max iterations reached, requesting final summary from LLM");

        // Add a message asking for summary
        let summary_request = ChatMessage::user(
            "You have reached the maximum number of tool call iterations. \
            Please provide your best answer based on the work completed so far."
        );
        messages.push(summary_request);

        // Convert messages to LLM format
        let messages_for_llm: Vec<Message> = messages
            .iter()
            .map(|m| self.chat_message_to_llm_message(m))
            .collect();

        let request = ChatCompletionRequest {
            messages: messages_for_llm,
            temperature: None,
            max_tokens: None,
            tools: None, // No tools in final summary call
        };

        match (*self.provider).chat(request).await {
            Ok(response) => {
                let assistant_message = ChatMessage::assistant(response.content);
                emitted_messages.push(assistant_message.clone());
                Ok(AgentProcessResult {
                    final_response: assistant_message,
                    emitted_messages,
                })
            }
            Err(e) => {
                // Fallback if summary call fails
                tracing::error!(error = %e, "Failed to get summary from LLM");
                let final_message = ChatMessage::assistant(
                    format!("I reached the maximum number of tool call iterations ({}) without completing the task. The work done so far has been lost due to an error. Please try breaking the task into smaller steps.", self.max_iterations)
                );
                emitted_messages.push(final_message.clone());
                Ok(AgentProcessResult {
                    final_response: final_message,
                    emitted_messages,
                })
            }
        }
    }

    /// Determine whether to execute tools in parallel or sequentially.
    ///
    /// Returns true if:
    /// - There are multiple tool calls
    /// - None of the tools require sequential execution (tool_search, non-concurrency-safe)
    fn should_execute_in_parallel(&self, tool_calls: &[ToolCall]) -> bool {
        if tool_calls.len() <= 1 {
            return false;
        }

        // tool_search must run sequentially to avoid MCP activation race conditions
        if tool_calls.iter().any(|tc| tc.name == "tool_search") {
            return false;
        }

        // All tools must be concurrency-safe to run in parallel
        tool_calls.iter().all(|tc| {
            self.tools
                .get(&tc.name)
                .map(|t| t.concurrency_safe())
                .unwrap_or(false)
        })
    }

    /// Execute multiple tool calls, choosing parallel or sequential based on conditions.
    async fn execute_tools(&self, tool_calls: &[ToolCall]) -> Vec<ToolExecutionOutcome> {
        if self.should_execute_in_parallel(tool_calls) {
            tracing::debug!("Executing {} tools in parallel", tool_calls.len());
            self.execute_tools_parallel(tool_calls).await
        } else {
            tracing::debug!("Executing {} tools sequentially", tool_calls.len());
            self.execute_tools_sequential(tool_calls).await
        }
    }

    /// Execute tools in parallel using join_all.
    async fn execute_tools_parallel(&self, tool_calls: &[ToolCall]) -> Vec<ToolExecutionOutcome> {
        let futures: Vec<_> = tool_calls
            .iter()
            .map(|tc| self.execute_one_tool(tc))
            .collect();

        futures_util::future::join_all(futures).await
    }

    /// Execute tools sequentially.
    async fn execute_tools_sequential(&self, tool_calls: &[ToolCall]) -> Vec<ToolExecutionOutcome> {
        let mut outcomes = Vec::with_capacity(tool_calls.len());

        for tool_call in tool_calls {
            outcomes.push(self.execute_one_tool(tool_call).await);
        }

        outcomes
    }

    /// Execute a single tool and return the outcome with event tracking.
    async fn execute_one_tool(&self, tool_call: &ToolCall) -> ToolExecutionOutcome {
        let start = Instant::now();
        let tool_name = tool_call.name.clone();

        // Record ToolCallStart event
        if let Some(ref observer) = self.observer {
            observer.record_event(&ObserverEvent::ToolCallStart {
                tool: tool_name.clone(),
                arguments: Some(truncate_args(&tool_call.arguments, 300)),
            });
        }

        let result = self.execute_tool_internal(tool_call).await;
        let duration = start.elapsed();

        // Record ToolCall event
        if let Some(ref observer) = self.observer {
            observer.record_event(&ObserverEvent::ToolCall {
                tool: tool_name.clone(),
                duration,
                success: result.success,
            });
        }

        // Apply duration
        ToolExecutionOutcome {
            duration,
            ..result
        }
    }

    /// Internal tool execution without event tracking.
    async fn execute_tool_internal(&self, tool_call: &ToolCall) -> ToolExecutionOutcome {
        let tool = match self.tools.get(&tool_call.name) {
            Some(t) => t,
            None => {
                tracing::warn!(tool = %tool_call.name, "Tool not found");
                return ToolExecutionOutcome::failure(
                    format!("Error: Tool '{}' not found", tool_call.name),
                    Some(format!("Tool '{}' not found", tool_call.name)),
                );
            }
        };

        match tool.execute(tool_call.arguments.clone()).await {
            Ok(result) => {
                if result.success {
                    ToolExecutionOutcome::success(result.output)
                } else {
                    let error = result.error.unwrap_or_default();
                    ToolExecutionOutcome::failure(
                        format!("Error: {}", error),
                        Some(error),
                    )
                }
            }
            Err(e) => {
                tracing::error!(tool = %tool_call.name, error = %e, "Tool execution failed");
                ToolExecutionOutcome::failure(
                    format!("Error: {}", e),
                    Some(e.to_string()),
                )
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::observability::{MultiObserver, Observer};

    struct TestObserver {
        events: std::sync::Mutex<Vec<ObserverEvent>>,
    }

    impl TestObserver {
        fn new() -> Self {
            Self {
                events: std::sync::Mutex::new(Vec::new()),
            }
        }
    }

    impl Observer for TestObserver {
        fn record_event(&self, event: &ObserverEvent) {
            self.events.lock().unwrap().push(event.clone());
        }

        fn name(&self) -> &str {
            "test_observer"
        }
    }

    #[tokio::test]
    async fn test_observer_receives_tool_events() {
        // Verify MultiObserver works
        let mut multi = MultiObserver::new();
        multi.add_observer(Box::new(TestObserver::new()));

        let event = ObserverEvent::ToolCallStart {
            tool: "test".to_string(),
            arguments: Some("{}".to_string()),
        };
        multi.record_event(&event);

        // Just verify the structure works
        assert_eq!(multi.len(), 1);
    }

    #[test]
    fn test_should_execute_in_parallel_single_tool() {
        // Would need a proper setup with AgentLoop to test fully
        // For now, just verify the logic: single tool should return false
        let calls = vec![ToolCall {
            id: "1".to_string(),
            name: "test".to_string(),
            arguments: serde_json::json!({}),
        }];

        // If there's only 1 tool, should return false regardless
        assert_eq!(calls.len() <= 1, true);
    }

    #[test]
    fn test_chat_message_to_llm_message_preserves_assistant_tool_calls() {
        use crate::providers::Message;

        let chat_message = ChatMessage::assistant_with_tool_calls(
            "calling tool",
            vec![ToolCall {
                id: "call_1".to_string(),
                name: "calculator".to_string(),
                arguments: serde_json::json!({ "expression": "2+2" }),
            }],
        );

        let content = vec![ContentBlock::text(&chat_message.content)];
        let provider_message = Message {
            role: chat_message.role.clone(),
            content,
            tool_call_id: chat_message.tool_call_id.clone(),
            name: chat_message.tool_name.clone(),
            tool_calls: chat_message.tool_calls.clone(),
        };

        assert_eq!(provider_message.role, "assistant");
        assert_eq!(provider_message.tool_calls.as_ref().unwrap().len(), 1);
        assert_eq!(provider_message.tool_calls.as_ref().unwrap()[0].id, "call_1");
        assert_eq!(provider_message.tool_calls.as_ref().unwrap()[0].name, "calculator");
    }
}

#[derive(Debug)]
pub enum AgentError {
    ProviderCreation(String),
    LlmError(String),
    Other(String),
}

impl std::fmt::Display for AgentError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            AgentError::ProviderCreation(e) => write!(f, "Provider creation error: {}", e),
            AgentError::LlmError(e) => write!(f, "LLM error: {}", e),
            AgentError::Other(e) => write!(f, "{}", e),
        }
    }
}

impl std::error::Error for AgentError {}