//! Tool definition: schema, parameters, and OpenAI-compatible tool objects.

use async_openai::types::chat::{ChatCompletionTool, FunctionObject};
use serde::{Deserialize, Serialize};

/// A JSON Schema parameter definition for a tool argument.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ToolParam {
    pub name: String,
    #[serde(rename = "type")]
    pub param_type: String,
    pub description: Option<String>,
    pub required: bool,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub properties: Option<std::collections::HashMap<String, ToolParam>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub items: Option<Box<ToolParam>>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ToolSchema {
    #[serde(rename = "type", default)]
    pub schema_type: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub properties: Option<std::collections::HashMap<String, ToolParam>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub required: Option<Vec<String>>,
}

impl Default for ToolSchema {
    fn default() -> Self {
        Self {
            schema_type: "object".to_string(),
            properties: None,
            required: None,
        }
    }
}

/// A tool definition with schema and metadata.
#[derive(Debug, Clone)]
pub struct ToolDefinition {
    pub name: String,
    pub description: Option<String>,
    pub parameters: Option<ToolSchema>,
    pub strict: bool,
}

impl ToolDefinition {
    pub fn new(name: impl Into<String>) -> Self {
        Self {
            name: name.into(),
            description: None,
            parameters: None,
            strict: false,
        }
    }

    pub fn description(mut self, description: impl Into<String>) -> Self {
        self.description = Some(description.into());
        self
    }

    pub fn parameters(mut self, schema: ToolSchema) -> Self {
        self.parameters = Some(schema);
        self
    }

    pub fn strict(mut self) -> Self {
        self.strict = true;
        self
    }

    pub fn to_openai_tool(&self) -> ChatCompletionTool {
        let parameters = self
            .parameters
            .as_ref()
            .map(|s| serde_json::to_value(s).unwrap_or(serde_json::Value::Null));

        ChatCompletionTool {
            function: FunctionObject {
                name: self.name.clone(),
                description: self.description.clone(),
                parameters,
                strict: if self.strict { Some(true) } else { None },
            },
        }
    }
}