use anyhow::Result;
use async_trait::async_trait;
use serde::{Deserialize, Serialize};

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum Role {
    System,
    User,
    Assistant,
    Tool,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Message {
    pub role: Role,
    pub content: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tool_calls: Option<Vec<ToolCall>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tool_call_id: Option<String>,
}

impl Message {
    pub fn system(content: impl Into<String>) -> Self {
        Self {
            role: Role::System,
            content: content.into(),
            tool_calls: None,
            tool_call_id: None,
        }
    }

    pub fn user(content: impl Into<String>) -> Self {
        Self {
            role: Role::User,
            content: content.into(),
            tool_calls: None,
            tool_call_id: None,
        }
    }

    pub fn assistant(content: impl Into<String>) -> Self {
        Self {
            role: Role::Assistant,
            content: content.into(),
            tool_calls: None,
            tool_call_id: None,
        }
    }

    pub fn tool(content: impl Into<String>, tool_call_id: String) -> Self {
        Self {
            role: Role::Tool,
            content: content.into(),
            tool_calls: None,
            tool_call_id: Some(tool_call_id),
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ToolCall {
    pub id: String,
    #[serde(rename = "type")]
    pub call_type: String,
    pub function: FunctionCall,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FunctionCall {
    pub name: String,
    pub arguments: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ToolDefinition {
    #[serde(rename = "type")]
    pub tool_type: String,
    pub function: FunctionDefinition,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FunctionDefinition {
    pub name: String,
    pub description: String,
    pub parameters: serde_json::Value,
}

#[derive(Debug)]
pub struct ChatResponse {
    pub content: String,
    pub tool_calls: Option<Vec<ToolCall>>,
    pub finish_reason: String,
}

#[async_trait]
pub trait LLMProvider: Send + Sync {
    /// Send a chat completion request
    async fn chat(&self, messages: Vec<Message>, tools: Option<Vec<ToolDefinition>>) -> Result<ChatResponse>;

    /// Get the model name
    fn model_name(&self) -> &str;
}