//! Core agent orchestration for the Owlen AI agent.
//!
//! This crate provides the central engine that coordinates Large Language Models (LLMs),
//! a rich set of system tools, and user interaction through an event-driven loop.

pub mod session;
pub mod system_prompt;
pub mod git;
pub mod compact;
pub mod messages;
pub mod state;

use color_eyre::eyre::{Result, eyre};
use futures_util::StreamExt;
use llm_core::{ChatMessage, ChatOptions, LlmProvider, Tool, ToolParameters};
use permissions::{PermissionDecision, PermissionManager, Tool as PermTool};
use jsonrpc;
use plugins::{ExternalToolDefinition, ExternalToolTransport};
use serde_json::{json, Value};
use std::collections::HashMap;
use std::path::PathBuf;
use std::sync::Arc;
use tokio::sync::{mpsc, RwLock};
use tools_ask::AskSender;
use tools_bash::ShellManager;
use tools_todo::TodoList;

pub use session::{
    SessionStats, SessionHistory, ToolCallRecord,
    Checkpoint, CheckpointManager, FileDiff, ToolCallsBuilder,
};
pub use system_prompt::{
    SystemPromptBuilder, default_base_prompt, generate_tool_instructions,
};
pub use git::{
    GitState, GitFileStatus,
    detect_git_state, is_safe_git_command, is_destructive_git_command,
    format_git_status,
};

// Re-export planning mode types
pub use tools_plan::{
    // Agent mode (document-based planning)
    AgentMode, PlanManager, PlanStatus, PlanMetadata,
    // Plan execution types (tool call accumulation)
    PlanStep, AccumulatedPlan, AccumulatedPlanStatus, PlanApproval,
    // Helper functions
    enter_plan_mode, exit_plan_mode, is_tool_allowed_in_plan_mode,
};

// Re-export compaction types
pub use compact::{Compactor, TokenCounter};

/// Events emitted during agent loop execution
#[derive(Debug, Clone)]
pub enum AgentEvent {
    /// LLM is generating text
    TextDelta(String),

    /// Tool execution starting
    ToolStart {
        tool_name: String,
        tool_id: String,
    },

    /// Tool produced output (may be partial)
    ToolOutput {
        tool_id: String,
        content: String,
        is_error: bool,
    },

    /// Tool execution completed
    ToolEnd {
        tool_id: String,
        success: bool,
    },

    /// Agent loop completed
    Done {
        final_response: String,
    },

    /// Error occurred
    Error(String),
}

pub type AgentEventSender = mpsc::Sender<AgentEvent>;
pub type AgentEventReceiver = mpsc::Receiver<AgentEvent>;

/// Creates a channel for agent events with a buffer size of 100.
pub fn create_event_channel() -> (AgentEventSender, AgentEventReceiver) {
    mpsc::channel(100)
}

/// Optional context for tools that need external dependencies or shared state.
#[derive(Clone)]
pub struct ToolContext {
    /// Todo list for the `todo_write` tool.
    pub todo_list: Option<TodoList>,

    /// Channel for asking user questions via the `ask_user` tool.
    pub ask_sender: Option<AskSender>,

    /// Shell manager for handling background shells.
    pub shell_manager: Option<ShellManager>,

    /// Plan manager for managing implementation plans in planning mode.
    pub plan_manager: Option<Arc<PlanManager>>,

    /// Current agent mode (e.g., Normal or Planning).
    pub agent_mode: Arc<RwLock<AgentMode>>,

    /// Registry of external tools from plugins
    pub external_tools: Arc<HashMap<String, ExternalToolDefinition>>,
}

impl Default for ToolContext {
    fn default() -> Self {
        Self {
            todo_list: None,
            ask_sender: None,
            shell_manager: None,
            plan_manager: None,
            agent_mode: Arc::new(RwLock::new(AgentMode::Normal)),
            external_tools: Arc::new(HashMap::new()),
        }
    }
}

impl ToolContext {
    /// Creates a new, empty `ToolContext`.
    pub fn new() -> Self {
        Self::default()
    }

    /// Adds a `TodoList` to the context.
    pub fn with_todo_list(mut self, list: TodoList) -> Self {
        self.todo_list = Some(list);
        self
    }

    /// Adds an `AskSender` to the context for user interaction.
    pub fn with_ask_sender(mut self, sender: AskSender) -> Self {
        self.ask_sender = Some(sender);
        self
    }

    /// Adds a `ShellManager` to the context for managing bash sessions.
    pub fn with_shell_manager(mut self, manager: ShellManager) -> Self {
        self.shell_manager = Some(manager);
        self
    }

    /// Adds a `PlanManager` to the context.
    pub fn with_plan_manager(mut self, manager: PlanManager) -> Self {
        self.plan_manager = Some(Arc::new(manager));
        self
    }

    /// Initializes a `PlanManager` with the given project root and adds it to the context.
    pub fn with_project_root(mut self, project_root: PathBuf) -> Self {
        self.plan_manager = Some(Arc::new(PlanManager::new(project_root)));
        self
    }

    /// Checks if the agent is currently in planning mode.
    pub async fn is_planning(&self) -> bool {
        self.agent_mode.read().await.is_planning()
    }

    /// Returns the current `AgentMode`.
    pub async fn get_mode(&self) -> AgentMode {
        self.agent_mode.read().await.clone()
    }

    /// Sets the current `AgentMode`.
    pub async fn set_mode(&self, mode: AgentMode) {
        *self.agent_mode.write().await = mode;
    }

    /// Adds external tools from plugins to the context.
    pub fn with_external_tools(mut self, tools: HashMap<String, ExternalToolDefinition>) -> Self {
        self.external_tools = Arc::new(tools);
        self
    }

    /// Gets an external tool by name, if it exists.
    pub fn get_external_tool(&self, name: &str) -> Option<&ExternalToolDefinition> {
        self.external_tools.get(name)
    }

    /// Returns true if an external tool with the given name exists.
    pub fn has_external_tool(&self, name: &str) -> bool {
        self.external_tools.contains_key(name)
    }
}

/// Returns definitions for all available tools that the agent can use.
pub fn get_tool_definitions() -> Vec<Tool> {
    vec![
        Tool::function(
            "read",
            "Read the contents of a file",
            ToolParameters::object(
                json!({
                    "path": {
                        "type": "string",
                        "description": "The path to the file to read"
                    }
                }),
                vec!["path".to_string()],
            ),
        ),
        Tool::function(
            "glob",
            "Find files matching a glob pattern (e.g., '**/*.rs' for all Rust files)",
            ToolParameters::object(
                json!({
                    "pattern": {
                        "type": "string",
                        "description": "Glob pattern to match files (e.g., '**/*.toml', '*.md')"
                    }
                }),
                vec!["pattern".to_string()],
            ),
        ),
        Tool::function(
            "grep",
            "Search for a pattern in files within a directory",
            ToolParameters::object(
                json!({
                    "root": {
                        "type": "string",
                        "description": "Root directory to search in"
                    },
                    "pattern": {
                        "type": "string",
                        "description": "Pattern to search for"
                    }
                }),
                vec!["root".to_string(), "pattern".to_string()],
            ),
        ),
        Tool::function(
            "write",
            "Write content to a file",
            ToolParameters::object(
                json!({
                    "path": {
                        "type": "string",
                        "description": "Path where the file should be written"
                    },
                    "content": {
                        "type": "string",
                        "description": "Content to write to the file"
                    }
                }),
                vec!["path".to_string(), "content".to_string()],
            ),
        ),
        Tool::function(
            "edit",
            "Edit a file by replacing old text with new text",
            ToolParameters::object(
                json!({
                    "path": {
                        "type": "string",
                        "description": "Path to the file to edit"
                    },
                    "old_string": {
                        "type": "string",
                        "description": "Text to find and replace"
                    },
                    "new_string": {
                        "type": "string",
                        "description": "Text to replace with"
                    }
                }),
                vec!["path".to_string(), "old_string".to_string(), "new_string".to_string()],
            ),
        ),
        Tool::function(
            "bash",
            "Execute a bash command. Use carefully and only when necessary.",
            ToolParameters::object(
                json!({
                    "command": {
                        "type": "string",
                        "description": "The bash command to execute"
                    }
                }),
                vec!["command".to_string()],
            ),
        ),
        Tool::function(
            "multi_edit",
            "Apply multiple edits to a file atomically",
            ToolParameters::object(
                json!({
                    "path": {
                        "type": "string",
                        "description": "Path to the file to edit"
                    },
                    "edits": {
                        "type": "array",
                        "items": {
                            "type": "object",
                            "properties": {
                                "old_string": { "type": "string" },
                                "new_string": { "type": "string" }
                            },
                            "required": ["old_string", "new_string"]
                        },
                        "description": "List of edit operations"
                    }
                }),
                vec!["path".to_string(), "edits".to_string()],
            ),
        ),
        Tool::function(
            "ls",
            "List contents of a directory",
            ToolParameters::object(
                json!({
                    "path": {
                        "type": "string",
                        "description": "Directory path to list"
                    },
                    "show_hidden": {
                        "type": "boolean",
                        "description": "Show hidden files",
                        "default": false
                    }
                }),
                vec!["path".to_string()],
            ),
        ),
        Tool::function(
            "web_search",
            "Search the web for information",
            ToolParameters::object(
                json!({
                    "query": {
                        "type": "string",
                        "description": "Search query"
                    },
                    "max_results": {
                        "type": "integer",
                        "description": "Maximum results",
                        "default": 10
                    }
                }),
                vec!["query".to_string()],
            ),
        ),
        Tool::function(
            "todo_write",
            "Update the task list",
            ToolParameters::object(
                json!({
                    "todos": {
                        "type": "array",
                        "items": {
                            "type": "object",
                            "properties": {
                                "content": { "type": "string" },
                                "status": {
                                    "type": "string",
                                    "enum": ["pending", "in_progress", "completed"]
                                },
                                "active_form": { "type": "string" }
                            },
                            "required": ["content", "status", "active_form"]
                        }
                    }
                }),
                vec!["todos".to_string()],
            ),
        ),
        Tool::function(
            "ask_user",
            "Ask the user a question with options",
            ToolParameters::object(
                json!({
                    "questions": {
                        "type": "array",
                        "items": {
                            "type": "object",
                            "properties": {
                                "question": { "type": "string" },
                                "header": { "type": "string" },
                                "options": {
                                    "type": "array",
                                    "items": {
                                        "type": "object",
                                        "properties": {
                                            "label": { "type": "string" },
                                            "description": { "type": "string" }
                                        }
                                    }
                                },
                                "multi_select": { "type": "boolean" }
                            }
                        }
                    }
                }),
                vec!["questions".to_string()],
            ),
        ),
        Tool::function(
            "bash_output",
            "Get output from a background shell",
            ToolParameters::object(
                json!({
                    "shell_id": {
                        "type": "string",
                        "description": "ID of the background shell"
                    }
                }),
                vec!["shell_id".to_string()],
            ),
        ),
        Tool::function(
            "kill_shell",
            "Terminate a background shell",
            ToolParameters::object(
                json!({
                    "shell_id": {
                        "type": "string",
                        "description": "ID of the shell to kill"
                    }
                }),
                vec!["shell_id".to_string()],
            ),
        ),
        Tool::function(
            "enter_plan_mode",
            "Enter planning mode for complex tasks that require careful planning before implementation. In planning mode, only read-only tools are available.",
            ToolParameters::object(
                json!({}),
                vec![],
            ),
        ),
        Tool::function(
            "exit_plan_mode",
            "Exit planning mode after presenting the implementation plan. The plan will be shown to the user for approval.",
            ToolParameters::object(
                json!({}),
                vec![],
            ),
        ),
    ]
}

/// Converts an external tool definition to an LLM-compatible Tool definition.
fn external_tool_to_llm_tool(ext: &ExternalToolDefinition) -> Tool {
    // Convert ExternalToolSchema to the JSON format expected by ToolParameters
    let properties: serde_json::Map<String, Value> = ext.input_schema.properties
        .iter()
        .map(|(k, v)| (k.clone(), v.clone()))
        .collect();

    Tool::function(
        &ext.name,
        &ext.description,
        ToolParameters::object(
            Value::Object(properties),
            ext.input_schema.required.clone(),
        ),
    )
}

/// Returns all tool definitions including external tools from plugins.
///
/// This function merges the built-in tools with any external tools
/// registered in the ToolContext.
pub fn get_tool_definitions_with_external(ctx: &ToolContext) -> Vec<Tool> {
    let mut tools = get_tool_definitions();

    // Add external tools from plugins
    for ext_tool in ctx.external_tools.values() {
        tools.push(external_tool_to_llm_tool(ext_tool));
    }

    tools
}

/// Executes a single tool call and returns its result as a string.
///
/// This function handles permission checking and interacts with various tool-specific
/// backends (filesystem, shell, etc.) using the provided `ToolContext`.
pub async fn execute_tool(
    tool_name: &str,
    arguments: &Value,
    perms: &PermissionManager,
    ctx: &ToolContext,
) -> Result<String> {
    match tool_name {
        "read" => {
            let path = arguments["path"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'path' argument"))?;

            // Check permission
            match perms.check(PermTool::Read, Some(path)) {
                PermissionDecision::Allow => {
                    let content = tools_fs::read_file(path)?;
                    Ok(content)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: Read operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: Read operation is blocked"))
                }
            }
        }
        "glob" => {
            let pattern = arguments["pattern"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'pattern' argument"))?;

            // Check permission
            match perms.check(PermTool::Glob, None) {
                PermissionDecision::Allow => {
                    let files = tools_fs::glob_list(pattern)?;
                    Ok(files.join("\n"))
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: Glob operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: Glob operation is blocked"))
                }
            }
        }
        "grep" => {
            let root = arguments["root"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'root' argument"))?;
            let pattern = arguments["pattern"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'pattern' argument"))?;

            // Check permission
            match perms.check(PermTool::Grep, None) {
                PermissionDecision::Allow => {
                    let results = tools_fs::grep(root, pattern)?;
                    let lines: Vec<String> = results
                        .into_iter()
                        .map(|(path, line_num, text)| format!("{}:{}:{}", path, line_num, text))
                        .collect();
                    Ok(lines.join("\n"))
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: Grep operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: Grep operation is blocked"))
                }
            }
        }
        "write" => {
            let path = arguments["path"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'path' argument"))?;
            let content = arguments["content"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'content' argument"))?;

            // Check permission
            match perms.check(PermTool::Write, Some(path)) {
                PermissionDecision::Allow => {
                    tools_fs::write_file(path, content)?;
                    Ok(format!("File written successfully: {}", path))
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: Write operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: Write operation is blocked"))
                }
            }
        }
        "edit" => {
            let path = arguments["path"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'path' argument"))?;
            let old_string = arguments["old_string"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'old_string' argument"))?;
            let new_string = arguments["new_string"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'new_string' argument"))?;

            // Check permission
            match perms.check(PermTool::Edit, Some(path)) {
                PermissionDecision::Allow => {
                    tools_fs::edit_file(path, old_string, new_string)?;
                    Ok(format!("File edited successfully: {}", path))
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: Edit operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: Edit operation is blocked"))
                }
            }
        }
        "bash" => {
            let command = arguments["command"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'command' argument"))?;

            // Check permission
            match perms.check(PermTool::Bash, Some(command)) {
                PermissionDecision::Allow => {
                    let mut session = tools_bash::BashSession::new().await?;
                    let output = session.execute(command, None).await?;
                    let result = if !output.stdout.is_empty() {
                        output.stdout
                    } else if !output.stderr.is_empty() {
                        format!("stderr: {}", output.stderr)
                    } else {
                        "Command executed successfully with no output".to_string()
                    };
                    Ok(result)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: Bash operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: Bash operation is blocked"))
                }
            }
        }
        "multi_edit" => {
            let path = arguments["path"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'path' argument"))?;
            let edits_value = arguments["edits"]
                .as_array()
                .ok_or_else(|| eyre!("Missing or invalid 'edits' argument"))?;

            // Parse edits
            let edits: Vec<tools_fs::EditOperation> = serde_json::from_value(json!(edits_value))?;

            // Check permission
            match perms.check(PermTool::MultiEdit, Some(path)) {
                PermissionDecision::Allow => {
                    let result = tools_fs::multi_edit_file(path, edits)?;
                    Ok(result)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: MultiEdit operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: MultiEdit operation is blocked"))
                }
            }
        }
        "ls" => {
            let path = arguments["path"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'path' argument"))?;
            let show_hidden = arguments.get("show_hidden")
                .and_then(|v| v.as_bool())
                .unwrap_or(false);

            // Check permission
            match perms.check(PermTool::LS, Some(path)) {
                PermissionDecision::Allow => {
                    let entries = tools_fs::list_directory(path, show_hidden)?;
                    let output = entries
                        .into_iter()
                        .map(|e| {
                            let type_marker = if e.is_dir { "/" } else { "" };
                            let size = e.size.map(|s| format!(" ({}B)", s)).unwrap_or_default();
                            format!("{}{}{}", e.name, type_marker, size)
                        })
                        .collect::<Vec<_>>()
                        .join("\n");
                    Ok(output)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: LS operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: LS operation is blocked"))
                }
            }
        }
        "web_search" => {
            let query = arguments["query"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'query' argument"))?;
            let max_results = arguments.get("max_results")
                .and_then(|v| v.as_u64())
                .unwrap_or(10) as usize;

            // Check permission
            match perms.check(PermTool::WebSearch, None) {
                PermissionDecision::Allow => {
                    // Use DuckDuckGo search provider
                    let provider = Box::new(tools_web::DuckDuckGoSearchProvider::with_max_results(max_results));
                    let client = tools_web::WebSearchClient::new(provider);
                    let results = client.search(query).await?;
                    let formatted = tools_web::format_search_results(&results);
                    Ok(formatted)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: WebSearch operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: WebSearch operation is blocked"))
                }
            }
        }
        "todo_write" => {
            let todo_list = ctx.todo_list.as_ref()
                .ok_or_else(|| eyre!("TodoList not available in this context"))?;

            // Check permission
            match perms.check(PermTool::TodoWrite, None) {
                PermissionDecision::Allow => {
                    let todos = tools_todo::parse_todos(arguments)?;
                    todo_list.write(todos);
                    Ok(todo_list.format_display())
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: TodoWrite operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: TodoWrite operation is blocked"))
                }
            }
        }
        "ask_user" => {
            let sender = ctx.ask_sender.as_ref()
                .ok_or_else(|| eyre!("AskUser not available in this context"))?;

            // Check permission
            match perms.check(PermTool::AskUserQuestion, None) {
                PermissionDecision::Allow => {
                    let questions = tools_ask::parse_questions(arguments)?;
                    let answers = tools_ask::ask_user(sender, questions).await?;
                    Ok(serde_json::to_string_pretty(&answers)?)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: AskUser operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: AskUser operation is blocked"))
                }
            }
        }
        "bash_output" => {
            let manager = ctx.shell_manager.as_ref()
                .ok_or_else(|| eyre!("ShellManager not available in this context"))?;

            let shell_id = arguments["shell_id"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'shell_id' argument"))?;

            // Check permission
            match perms.check(PermTool::BashOutput, Some(shell_id)) {
                PermissionDecision::Allow => {
                    tools_bash::bash_output(manager, shell_id)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: BashOutput operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: BashOutput operation is blocked"))
                }
            }
        }
        "kill_shell" => {
            let manager = ctx.shell_manager.as_ref()
                .ok_or_else(|| eyre!("ShellManager not available in this context"))?;

            let shell_id = arguments["shell_id"]
                .as_str()
                .ok_or_else(|| eyre!("Missing 'shell_id' argument"))?;

            // Check permission
            match perms.check(PermTool::KillShell, Some(shell_id)) {
                PermissionDecision::Allow => {
                    tools_bash::kill_shell(manager, shell_id)
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: KillShell operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: KillShell operation is blocked"))
                }
            }
        }
        "enter_plan_mode" => {
            let plan_manager = ctx.plan_manager.as_ref()
                .ok_or_else(|| eyre!("PlanManager not available - cannot enter planning mode"))?;

            // Check permission
            match perms.check(PermTool::EnterPlanMode, None) {
                PermissionDecision::Allow => {
                    // Check if already in planning mode
                    if ctx.is_planning().await {
                        return Err(eyre!("Already in planning mode"));
                    }

                    // Create plan file
                    let plan_path = plan_manager.create_plan().await?;

                    // Enter planning mode
                    ctx.set_mode(tools_plan::enter_plan_mode(plan_path.clone())).await;

                    Ok(format!(
                        "Entered planning mode. Plan file created at: {}\n\n\
                        In planning mode, only read-only tools are available. \
                        Use `exit_plan_mode` when you have finished writing your plan.",
                        plan_path.display()
                    ))
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: EnterPlanMode operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: EnterPlanMode operation is blocked"))
                }
            }
        }
        "exit_plan_mode" => {
            // Check permission
            match perms.check(PermTool::ExitPlanMode, None) {
                PermissionDecision::Allow => {
                    // Check if in planning mode
                    let mode = ctx.get_mode().await;
                    match mode {
                        AgentMode::Planning { plan_file, started_at } => {
                            let plan_manager = ctx.plan_manager.as_ref()
                                .ok_or_else(|| eyre!("PlanManager not available"))?;

                            // Read the plan content
                            let plan_content = plan_manager.read_plan(&plan_file).await
                                .unwrap_or_else(|_| "No plan content written.".to_string());

                            // Update plan status to pending approval
                            let _ = plan_manager.set_status(&plan_file, tools_plan::PlanStatus::PendingApproval).await;

                            // Exit planning mode
                            ctx.set_mode(tools_plan::exit_plan_mode()).await;

                            let duration = chrono::Utc::now().signed_duration_since(started_at);
                            let minutes = duration.num_minutes();

                            Ok(format!(
                                "Exited planning mode after {} minutes.\n\n\
                                Plan file: {}\n\n\
                                ## Plan Content:\n\n{}\n\n\
                                The plan is now awaiting your approval.",
                                minutes,
                                plan_file.display(),
                                plan_content
                            ))
                        }
                        AgentMode::Normal => {
                            Err(eyre!("Not in planning mode"))
                        }
                    }
                }
                PermissionDecision::Ask => {
                    Err(eyre!("Permission required: ExitPlanMode operation needs approval"))
                }
                PermissionDecision::Deny => {
                    Err(eyre!("Permission denied: ExitPlanMode operation is blocked"))
                }
            }
        }
        // Check for external tools from plugins
        _ => {
            // Look up the tool in the external tools registry
            if let Some(ext_tool) = ctx.get_external_tool(tool_name) {
                // Check permission for external tool execution
                // External tools require explicit permission (treated like Bash)
                match perms.check(PermTool::Bash, Some(&format!("external:{}", tool_name))) {
                    PermissionDecision::Allow => {
                        execute_external_tool(ext_tool, arguments).await
                    }
                    PermissionDecision::Ask => {
                        Err(eyre!("Permission required: External tool '{}' needs approval", tool_name))
                    }
                    PermissionDecision::Deny => {
                        Err(eyre!("Permission denied: External tool '{}' is blocked", tool_name))
                    }
                }
            } else {
                Err(eyre!("Unknown tool: {}", tool_name))
            }
        }
    }
}

/// Executes an external tool via JSON-RPC.
async fn execute_external_tool(
    tool: &ExternalToolDefinition,
    arguments: &Value,
) -> Result<String> {
    match &tool.transport {
        ExternalToolTransport::Stdio => {
            // Get command and args
            let command = tool.command.as_ref()
                .ok_or_else(|| eyre!("Stdio tool '{}' missing command", tool.name))?;

            // Spawn the process and call via JSON-RPC
            let executor = jsonrpc::ToolExecutor::with_timeout(tool.timeout_ms);
            let result = executor.execute_stdio(
                command,
                &tool.args,
                &std::collections::HashMap::new(), // TODO: env vars from plugin
                arguments.clone(),
                Some(tool.timeout_ms),
            ).await?;

            // Convert JSON result to string
            match result {
                Value::String(s) => Ok(s),
                other => Ok(serde_json::to_string_pretty(&other)?),
            }
        }
        ExternalToolTransport::Http => {
            let url = tool.url.as_ref()
                .ok_or_else(|| eyre!("HTTP tool '{}' missing url", tool.name))?;

            // HTTP transport not yet implemented
            Err(eyre!("HTTP transport for tool '{}' at {} is not yet implemented", tool.name, url))
        }
    }
}

/// Runs the core agent loop for a given user prompt.
///
/// This function iteratively calls the LLM provider, processes tool execution requests,
/// and feeds the results back to the model until a final text response is generated
/// or the iteration limit is reached.
pub async fn run_agent_loop<P: LlmProvider>(
    provider: &P,
    user_prompt: &str,
    options: &ChatOptions,
    perms: &PermissionManager,
    ctx: &ToolContext,
) -> Result<String> {
    let tools = get_tool_definitions();
    let mut messages = vec![ChatMessage::user(user_prompt)];

    let max_iterations = 10; // Prevent infinite loops
    let mut iteration = 0;

    loop {
        iteration += 1;
        if iteration > max_iterations {
            return Err(eyre!("Max iterations reached"));
        }

        // Call LLM with messages and tools
        let mut stream = provider
            .chat_stream(&messages, options, Some(&tools))
            .await
            .map_err(|e| eyre!("LLM provider error: {}", e))?;

        let mut response_content = String::new();
        let mut accumulated_tool_calls: Vec<llm_core::ToolCall> = Vec::new();

        // Collect the streamed response
        while let Some(chunk) = stream.next().await {
            let chunk = chunk.map_err(|e| eyre!("Stream error: {}", e))?;

            if let Some(content) = chunk.content {
                response_content.push_str(&content);
            }

            // Accumulate tool calls from deltas
            if let Some(deltas) = chunk.tool_calls {
                for delta in deltas {
                    // Ensure the accumulated_tool_calls vec is large enough
                    while accumulated_tool_calls.len() <= delta.index {
                        accumulated_tool_calls.push(llm_core::ToolCall {
                            id: String::new(),
                            call_type: "function".to_string(),
                            function: llm_core::FunctionCall {
                                name: String::new(),
                                arguments: Value::Null,
                            },
                        });
                    }

                    let tool_call = &mut accumulated_tool_calls[delta.index];

                    if let Some(id) = delta.id {
                        tool_call.id = id;
                    }
                    if let Some(name) = delta.function_name {
                        tool_call.function.name = name;
                    }
                    if let Some(args_delta) = delta.arguments_delta {
                        // Accumulate the arguments string
                        let current_args = if tool_call.function.arguments.is_null() {
                            String::new()
                        } else {
                            tool_call.function.arguments.to_string()
                        };
                        let new_args = current_args + &args_delta;
                        // Try to parse as JSON, but keep as string if incomplete
                        tool_call.function.arguments = serde_json::from_str(&new_args)
                            .unwrap_or(Value::String(new_args));
                    }
                }
            }
        }

        // Drop the stream to release the borrow on messages
        drop(stream);

        // Filter out incomplete tool calls and check if we have valid ones
        let valid_tool_calls: Vec<_> = accumulated_tool_calls
            .into_iter()
            .filter(|tc| !tc.id.is_empty() && !tc.function.name.is_empty())
            .collect();

        // Check if LLM wants to call tools
        if !valid_tool_calls.is_empty() {
            // Add assistant message with tool calls
            messages.push(ChatMessage {
                role: llm_core::Role::Assistant,
                content: if response_content.is_empty() {
                    None
                } else {
                    Some(response_content.clone())
                },
                tool_calls: Some(valid_tool_calls.clone()),
                tool_call_id: None,
                name: None,
            });

            // Execute each tool call
            for call in valid_tool_calls {
                let tool_name = &call.function.name;
                let arguments = &call.function.arguments;

                tracing::debug!(tool = %tool_name, args = %arguments, "executing tool call");

                match execute_tool(tool_name, arguments, perms, ctx).await {
                    Ok(result) => {
                        tracing::debug!(tool = %tool_name, result = %result, "tool call succeeded");
                        // Add tool result message
                        messages.push(ChatMessage::tool_result(&call.id, result));
                    }
                    Err(e) => {
                        tracing::warn!(tool = %tool_name, error = %e, "tool call failed");
                        // Add error message as tool result
                        messages.push(ChatMessage::tool_result(&call.id, format!("Error: {}", e)));
                    }
                }
            }

            // Continue loop to get next response
            continue;
        }

        // No tool calls, we're done
        return Ok(response_content);
    }
}

/// Runs the agent loop and streams events back through the provided channel.
///
/// This allows UIs to provide real-time feedback as the LLM generates text and
/// as tools are being executed.
pub async fn run_agent_loop_streaming<P: LlmProvider>(
    provider: &P,
    user_prompt: &str,
    options: &ChatOptions,
    perms: &PermissionManager,
    ctx: &ToolContext,
    events: AgentEventSender,
) -> Result<String> {
    let tools = get_tool_definitions();
    let mut messages = vec![ChatMessage::user(user_prompt)];

    let max_iterations = 10;
    let mut iteration = 0;

    loop {
        iteration += 1;
        if iteration > max_iterations {
            let _ = events.send(AgentEvent::Error("Max iterations reached".into())).await;
            return Err(eyre!("Max iterations reached"));
        }

        // Stream LLM response
        let mut stream = provider
            .chat_stream(&messages, options, Some(&tools))
            .await
            .map_err(|e| {
                let err_msg = format!("LLM provider error: {}", e);
                let _ = events.try_send(AgentEvent::Error(err_msg.clone()));
                eyre!(err_msg)
            })?;

        let mut response_content = String::new();
        let mut tool_calls_builder = ToolCallsBuilder::new();

        while let Some(chunk) = stream.next().await {
            let chunk = chunk.map_err(|e| {
                let err_msg = format!("Stream error: {}", e);
                let _ = events.try_send(AgentEvent::Error(err_msg.clone()));
                eyre!(err_msg)
            })?;

            // Send text deltas
            if let Some(text) = &chunk.content {
                let _ = events.send(AgentEvent::TextDelta(text.clone())).await;
                response_content.push_str(text);
            }

            // Accumulate tool calls
            if let Some(deltas) = &chunk.tool_calls {
                tool_calls_builder.add_deltas(deltas);
            }
        }

        // Drop stream to release borrow
        drop(stream);

        let tool_calls = tool_calls_builder.build();

        if tool_calls.is_empty() {
            let _ = events
                .send(AgentEvent::Done {
                    final_response: response_content.clone(),
                })
                .await;
            return Ok(response_content);
        }

        // Add assistant message
        messages.push(ChatMessage {
            role: llm_core::Role::Assistant,
            content: if response_content.is_empty() {
                None
            } else {
                Some(response_content.clone())
            },
            tool_calls: Some(tool_calls.clone()),
            tool_call_id: None,
            name: None,
        });

        // Execute tools with events
        for call in &tool_calls {
            let tool_id = call.id.clone();
            let tool_name = call.function.name.clone();

            let _ = events
                .send(AgentEvent::ToolStart {
                    tool_name: tool_name.clone(),
                    tool_id: tool_id.clone(),
                })
                .await;

            tracing::debug!(tool = %tool_name, args = %call.function.arguments, "executing tool call");

            let result = execute_tool(&tool_name, &call.function.arguments, perms, ctx).await;

            match &result {
                Ok(output) => {
                    tracing::debug!(tool = %tool_name, result = %output, "tool call succeeded");
                    let _ = events
                        .send(AgentEvent::ToolOutput {
                            tool_id: tool_id.clone(),
                            content: output.clone(),
                            is_error: false,
                        })
                        .await;
                    let _ = events
                        .send(AgentEvent::ToolEnd {
                            tool_id: tool_id.clone(),
                            success: true,
                        })
                        .await;
                    messages.push(ChatMessage::tool_result(&tool_id, output));
                }
                Err(e) => {
                    tracing::warn!(tool = %tool_name, error = %e, "tool call failed");
                    let error_msg = e.to_string();
                    let _ = events
                        .send(AgentEvent::ToolOutput {
                            tool_id: tool_id.clone(),
                            content: error_msg.clone(),
                            is_error: true,
                        })
                        .await;
                    let _ = events
                        .send(AgentEvent::ToolEnd {
                            tool_id: tool_id.clone(),
                            success: false,
                        })
                        .await;
                    messages.push(ChatMessage::tool_result(
                        &tool_id,
                        format!("Error: {}", error_msg),
                    ));
                }
            }
        }
    }
}

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

    #[test]
    fn test_tool_calls_builder() {
        let mut builder = ToolCallsBuilder::new();
        
        // Add first tool call deltas
        builder.add_deltas(&[
            ToolCallDelta {
                index: 0,
                id: Some("call_1".to_string()),
                function_name: Some("read".to_string()),
                arguments_delta: Some("{\"path\":".to_string()),
            }
        ]);
        
        // Add second tool call deltas
        builder.add_deltas(&[
            ToolCallDelta {
                index: 1,
                id: Some("call_2".to_string()),
                function_name: Some("write".to_string()),
                arguments_delta: Some("{\"path\":\"test.txt\"".to_string()),
            }
        ]);
        
        // Add more deltas for first tool call
        builder.add_deltas(&[
            ToolCallDelta {
                index: 0,
                id: None,
                function_name: None,
                arguments_delta: Some("\"lib.rs\"}".to_string()),
            }
        ]);
        
        // Add more deltas for second tool call
        builder.add_deltas(&[
            ToolCallDelta {
                index: 1,
                id: None,
                function_name: None,
                arguments_delta: Some(",\"content\":\"hello\"}".to_string()),
            }
        ]);
        
        let calls = builder.build();
        assert_eq!(calls.len(), 2);
        
        assert_eq!(calls[0].id, "call_1");
        assert_eq!(calls[0].function.name, "read");
        assert_eq!(calls[0].function.arguments, json!({"path": "lib.rs"}));
        
        assert_eq!(calls[1].id, "call_2");
        assert_eq!(calls[1].function.name, "write");
        assert_eq!(calls[1].function.arguments, json!({"path": "test.txt", "content": "hello"}));
    }
}