import claude/client.{type Config}
import claude/types/tool.{type Registry, type ToolChoice}
import gleam/option.{type Option, None, Some}

/// Configuration for the agent loop.
pub type AgentConfig {
  AgentConfig(
    client: Config,
    model: String,
    max_tokens: Int,
    system: Option(String),
    tools: Registry,
    tool_choice: Option(ToolChoice),
    thinking: Option(Int),
    max_iterations: Int,
    tool_timeout_ms: Int,
  )
}

/// Create a new AgentConfig with sensible defaults.
///
/// Defaults:
/// - model: config.default_model
/// - max_tokens: config.default_max_tokens
/// - max_iterations: 10
/// - tool_timeout_ms: 30_000 (30 seconds)
pub fn new(
  client client: Config,
  tools tools: Registry,
) -> AgentConfig {
  AgentConfig(
    client: client,
    model: client.default_model,
    max_tokens: client.default_max_tokens,
    system: None,
    tools: tools,
    tool_choice: None,
    thinking: None,
    max_iterations: 10,
    tool_timeout_ms: 30_000,
  )
}

/// Set the system prompt.
pub fn with_system(config: AgentConfig, system: String) -> AgentConfig {
  AgentConfig(..config, system: Some(system))
}

/// Set the maximum number of agent loop iterations.
pub fn with_max_iterations(config: AgentConfig, max: Int) -> AgentConfig {
  AgentConfig(..config, max_iterations: max)
}

/// Set the model to use.
pub fn with_model(config: AgentConfig, model: String) -> AgentConfig {
  AgentConfig(..config, model: model)
}

/// Enable extended thinking with a budget (in tokens).
pub fn with_thinking(config: AgentConfig, budget: Int) -> AgentConfig {
  AgentConfig(..config, thinking: Some(budget))
}

/// Set the per-tool execution timeout in milliseconds.
pub fn with_tool_timeout(config: AgentConfig, timeout_ms: Int) -> AgentConfig {
  AgentConfig(..config, tool_timeout_ms: timeout_ms)
}

/// Set the max tokens for API calls.
pub fn with_max_tokens(config: AgentConfig, max_tokens: Int) -> AgentConfig {
  AgentConfig(..config, max_tokens: max_tokens)
}

/// Set the tool choice strategy.
pub fn with_tool_choice(
  config: AgentConfig,
  choice: ToolChoice,
) -> AgentConfig {
  AgentConfig(..config, tool_choice: Some(choice))
}