//! Request/response shapes for the Anthropic Messages API.
//!
//! Hand-rolled rather than pulled from an SDK: pydantic-ai has no Rust
//! equivalent, and the surface area we actually need (text, tool_use,
//! tool_result, forced tool choice) is small enough to own directly.

use serde::{Deserialize, Serialize};
use serde_json::Value;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Message {
    pub role: String,
    pub content: Vec<ContentBlock>,
}

impl Message {
    pub fn user_text(text: impl Into<String>) -> Self {
        Self {
            role: "user".into(),
            content: vec![ContentBlock::Text { text: text.into() }],
        }
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum ContentBlock {
    Text {
        text: String,
    },
    ToolUse {
        id: String,
        name: String,
        input: Value,
    },
    ToolResult {
        tool_use_id: String,
        content: String,
    },
    /// Anything else the API sends back (e.g. a `thinking` block) that this
    /// client doesn't act on but must not fail to deserialize.
    #[serde(other)]
    Unknown,
}

#[derive(Debug, Clone, Serialize)]
pub struct ToolSpec {
    pub name: String,
    pub description: String,
    pub input_schema: Value,
}

#[derive(Debug, Clone, Serialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum ToolChoice {
    Auto,
    Tool { name: String },
}

#[derive(Debug, Serialize)]
pub struct RequestBody<'a> {
    pub model: &'a str,
    pub max_tokens: u32,
    pub system: &'a str,
    pub messages: &'a [Message],
    pub tools: &'a [ToolSpec],
    pub tool_choice: ToolChoice,
}

#[derive(Debug, Deserialize)]
pub struct ResponseBody {
    #[serde(default)]
    pub content: Vec<ContentBlock>,
    #[serde(default)]
    pub stop_reason: Option<String>,
}