saya-agent 0.2.0

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

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AgentRequest {
    pub prompt: String,
    pub profile_names: Vec<String>,
    pub model: String,
    /// Optional extra system context appended to the base SAYA system prompt (e.g. available database connections).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub system_prompt: Option<String>,
    #[serde(default)]
    pub history: Vec<ChatMessage>,
}

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

impl ChatMessage {
    pub fn text(role: &str, content: impl Into<String>) -> Self {
        Self {
            role: role.into(),
            content: content.into(),
            tool_calls: Vec::new(),
            tool_call_id: None,
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct ToolCall {
    pub id: String,
    pub name: String,
    pub arguments: serde_json::Value,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct ToolMetadata {
    pub name: String,
    pub status: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ChatRequest {
    pub model: String,
    pub messages: Vec<ChatMessage>,
    pub tools: Vec<ToolDefinition>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ChatResponse {
    pub message: ChatMessage,
}

// `arguments` carries a `serde_json::Value`, which is not `Eq`, so this enum is
// `PartialEq` only.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum AgentEvent {
    AssistantText {
        text: String,
    },
    /// A tool was requested. `arguments` is the raw call payload (e.g. the SQL),
    /// surfaced so the user can see exactly what will run before approving it.
    ToolRequested {
        name: String,
        #[serde(default, skip_serializing_if = "serde_json::Value::is_null")]
        arguments: serde_json::Value,
    },
    ToolCompleted {
        name: String,
        summary: String,
    },
    ToolDenied {
        name: String,
        reason: String,
    },
    Complete,
}

#[async_trait]
pub trait ApprovalDecider: Send + Sync {
    /// Decides whether a tool call may run. `arguments` is the raw call payload
    /// so implementations can show the user what they are approving.
    async fn approve(&self, tool: &ToolDefinition, arguments: &serde_json::Value) -> bool;
}

pub struct AllowReadOnlyApproval;

#[async_trait]
impl ApprovalDecider for AllowReadOnlyApproval {
    async fn approve(&self, _: &ToolDefinition, _: &serde_json::Value) -> bool {
        true
    }
}

#[derive(Debug, thiserror::Error, Clone, PartialEq, Eq)]
pub enum ProviderError {
    #[error("provider request failed: {0}")]
    Request(String),
    #[error("provider returned an invalid response")]
    InvalidResponse,
    #[error("provider is not configured: {0}")]
    Configuration(String),
    #[error("provider stream was cancelled")]
    Cancelled,
}

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

#[async_trait]
pub trait ToolExecutor: Send + Sync {
    async fn execute(
        &self,
        name: &str,
        arguments: serde_json::Value,
    ) -> Result<serde_json::Value, String>;
}