recursive-agent 0.4.0

//! Runtime configuration.
//!
//! All of these can be overridden via env vars or CLI flags. Sensible
//! defaults make the binary runnable with just `RECURSIVE_API_KEY` and
//! `RECURSIVE_MODEL` set.

use std::path::{Path, PathBuf};

use crate::error::{Error, Result};

#[derive(Debug, Clone)]
pub struct Config {
    pub workspace: PathBuf,
    pub api_base: String,
    pub api_key: Option<String>,
    pub model: String,
    pub provider_type: String,
    pub max_steps: usize,
    pub temperature: f64,
    pub system_prompt: String,
    pub retry_max: usize,
    pub retry_initial_backoff_secs: u64,
    pub retry_max_backoff_secs: u64,
    pub shell_timeout_secs: u64,
}

impl Config {
    /// Load from environment, with config file (~/.recursive/config.toml) as fallback.
    /// Priority: env var > config file > hardcoded default.
    /// The API key is optional here so commands that don't need the LLM
    /// (e.g. `tools`, `config`) still run.
    pub fn from_env() -> Result<Self> {
        // Load file config (lowest priority, used as fallback)
        let file_config = crate::config_file::FileConfig::load()
            .map_err(|e| Error::Config {
                message: format!("config file: {e}"),
            })?
            .unwrap_or_default();
        let file_provider = file_config.provider.as_ref();
        let file_agent = file_config.agent.as_ref();

        let workspace = std::env::var("RECURSIVE_WORKSPACE")
            .map(PathBuf::from)
            .unwrap_or_else(|_| std::env::current_dir().unwrap_or_else(|_| PathBuf::from(".")));

        let api_base = std::env::var("RECURSIVE_API_BASE")
            .or_else(|_| std::env::var("OPENAI_API_BASE"))
            .ok()
            .or_else(|| file_provider.and_then(|p| p.api_base.clone()))
            .unwrap_or_else(|| "https://api.openai.com/v1".into());

        let api_key = std::env::var("RECURSIVE_API_KEY")
            .or_else(|_| std::env::var("OPENAI_API_KEY"))
            .ok()
            .or_else(|| file_provider.and_then(|p| p.api_key.clone()));

        let model = std::env::var("RECURSIVE_MODEL")
            .or_else(|_| std::env::var("OPENAI_MODEL"))
            .ok()
            .or_else(|| file_provider.and_then(|p| p.model.clone()))
            .unwrap_or_else(|| "gpt-4o-mini".into());

        let max_steps = std::env::var("RECURSIVE_MAX_STEPS")
            .ok()
            .and_then(|s| s.parse().ok())
            .or_else(|| file_agent.and_then(|a| a.max_steps))
            .unwrap_or(32);

        let temperature = std::env::var("RECURSIVE_TEMPERATURE")
            .ok()
            .and_then(|s| s.parse().ok())
            .or_else(|| file_agent.and_then(|a| a.temperature))
            .unwrap_or(0.2);

        let system_prompt = match std::env::var("RECURSIVE_SYSTEM_PROMPT_FILE") {
            Ok(path) => std::fs::read_to_string(&path).map_err(|e| Error::Config {
                message: format!("read system prompt {path}: {e}"),
            })?,
            Err(_) => default_system_prompt(),
        };

        let retry_max = std::env::var("RECURSIVE_RETRY_MAX")
            .ok()
            .and_then(|s| s.parse().ok())
            .unwrap_or(2);
        let retry_initial_backoff_secs = std::env::var("RECURSIVE_RETRY_INITIAL_BACKOFF_SECS")
            .ok()
            .and_then(|s| s.parse().ok())
            .unwrap_or(1);
        let retry_max_backoff_secs = std::env::var("RECURSIVE_RETRY_MAX_BACKOFF_SECS")
            .ok()
            .and_then(|s| s.parse().ok())
            .unwrap_or(8);
        let shell_timeout_secs = std::env::var("RECURSIVE_SHELL_TIMEOUT_SECS")
            .ok()
            .and_then(|s| s.parse().ok())
            .or_else(|| file_agent.and_then(|a| a.shell_timeout_secs))
            .unwrap_or(300);

        let provider_type = std::env::var("RECURSIVE_PROVIDER_TYPE")
            .ok()
            .or_else(|| file_provider.and_then(|p| p.provider_type.clone()))
            .unwrap_or_else(|| "openai".into());

        Ok(Self {
            workspace,
            api_base,
            api_key,
            model,
            provider_type,
            max_steps,
            temperature,
            system_prompt,
            retry_max,
            retry_initial_backoff_secs,
            retry_max_backoff_secs,
            shell_timeout_secs,
        })
    }

    /// Return the API key or a descriptive error if none was configured.
    pub fn require_api_key(&self) -> Result<&str> {
        self.api_key.as_deref().ok_or_else(|| Error::Config {
            message: "set RECURSIVE_API_KEY (or OPENAI_API_KEY)".into(),
        })
    }

    /// Validate that the config has enough information to run the agent.
    /// Returns a user-friendly error message if not.
    pub fn validate_for_agent(&self) -> std::result::Result<(), String> {
        if self.api_key.is_none() || self.api_key.as_deref() == Some("") {
            return Err("\
Error: No API key configured.

Set one of:
  --api-key <KEY>
  RECURSIVE_API_KEY=<KEY>
  OPENAI_API_KEY=<KEY>

Or create ~/.recursive/config.toml:
  [provider]
  api_key = \"your-key-here\"

Example:
  recursive --api-key sk-xxx --model deepseek-chat run \"hello\"
"
            .to_string());
        }
        if !["openai", "anthropic"].contains(&self.provider_type.as_str()) {
            return Err(format!(
                "\
Error: Unknown provider type '{}'.

Supported providers: openai, anthropic
Set via --provider or RECURSIVE_PROVIDER_TYPE.
",
                self.provider_type
            ));
        }
        Ok(())
    }
}

pub fn default_system_prompt() -> String {
    [
        "You are Recursive, a minimal but capable coding agent.",
        "",
        "Tools available: read_file, write_file, list_dir, run_shell, apply_patch, search_files.",
        "Additional tools: estimate_tokens (estimate token count for text or file).",
        "All file paths are workspace-relative; the sandbox will reject anything outside.",
        "",
        "Working principles:",
        "- Read before you write. Skim relevant files (read_file, list_dir) before editing.",
        "- Prefer apply_patch over write_file when modifying existing files. Use write_file only for new files or full rewrites.",
        "- After any non-trivial code change, run the project's tests via run_shell and quote the result.",
        "- If a tool call fails the same way twice, change approach instead of retrying.",
        "- Stop calling tools and write a short final summary once the task is done.",
        "",
        "Patching with apply_patch:",
        "- Use the V4A format (see AGENTS.md section 5 for the canonical reference).",
        "- Each `*** Update File:` block must appear at most once per patch.",
        "- The `@@ <anchor>` line cites an existing line; lines with leading space are unchanged context.",
        "- Example (editing src/example.rs to add a new function):",
        "```",
        "*** Begin Patch",
        "*** Update File: src/example.rs",
        "@@ fn existing_function() {",
        " fn existing_function();",
        "",
        "+fn new_function();",
        "+",
        " fn another_function();",
        "*** End Patch",
        "```",
        "",
        "Don't:",
        "- Do not run `git checkout`, `git reset`, `git restore`, or any command that mutates the working tree. The orchestrator owns rollback.",
        "- Do not edit source files via `sed -i`, `tail > file`, or `cat <<EOF`. Use apply_patch or write_file (whole file).",
        "- Verify behavior via `cargo test`, never via `cargo run | jq`. Cargo build noise on a fresh tree breaks jq parsing and burns your step budget.",
        "",
        "Output should be terse and concrete. Avoid filler.",
    ]
    .join("\n")
}

/// Maximum size for project context file (AGENTS.md) in bytes.
/// 16 KB is enough for a detailed project context without blowing
/// the context window.
const MAX_PROJECT_CONTEXT_SIZE: usize = 16 * 1024;

/// Load project context from AGENTS.md at workspace root.
///
/// Returns the file content if present, truncated to 16 KB with a
/// marker if larger. Returns None if absent.
pub fn load_project_context(workspace: &Path) -> Option<String> {
    let path = workspace.join("AGENTS.md");
    if !path.exists() {
        return None;
    }

    let metadata = std::fs::metadata(&path).ok()?;
    let file_size = metadata.len() as usize;

    if file_size <= MAX_PROJECT_CONTEXT_SIZE {
        let content = std::fs::read_to_string(&path).ok()?;
        Some(content)
    } else {
        // File is too large: read first 16 KB and append truncation marker
        let mut file = std::fs::File::open(&path).ok()?;
        use std::io::Read;
        let mut buffer = vec![0u8; MAX_PROJECT_CONTEXT_SIZE];
        let bytes_read = file.read(&mut buffer).ok()?;
        buffer.truncate(bytes_read);
        let content = String::from_utf8_lossy(&buffer).to_string();
        let truncated_msg = format!(
            "\n\n[…truncated, AGENTS.md is {} KB; consider trimming for fresh agent sessions]",
            file_size / 1024
        );
        Some(content + &truncated_msg)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn default_prompt_is_well_under_a_kilobyte() {
        assert!(default_system_prompt().len() < 2048);
    }

    #[test]
    fn default_prompt_mentions_apply_patch() {
        assert!(default_system_prompt().contains("apply_patch"));
    }

    #[test]
    fn default_prompt_mentions_run_shell_tests() {
        let prompt = default_system_prompt();
        assert!(prompt.contains("run_shell"));
        assert!(prompt.contains("tests"));
    }

    #[test]
    fn default_prompt_includes_new_sections() {
        let prompt = default_system_prompt();
        assert!(prompt.contains("apply_patch"));
        assert!(prompt.contains("git checkout"));
        assert!(prompt.contains("cargo test"));
        assert!(prompt.contains("*** Begin Patch"));
    }

    #[test]
    fn retry_defaults_match_old_policy() {
        // Ensure defaults match the hardcoded RetryPolicy::default()
        let config = Config {
            workspace: PathBuf::from("."),
            api_base: String::new(),
            api_key: None,
            model: String::new(),
            provider_type: "openai".into(),
            max_steps: 32,
            temperature: 0.2,
            system_prompt: String::new(),
            retry_max: 2,
            retry_initial_backoff_secs: 1,
            retry_max_backoff_secs: 8,
            shell_timeout_secs: 300,
        };
        assert_eq!(config.retry_max, 2);
        assert_eq!(config.retry_initial_backoff_secs, 1);
        assert_eq!(config.retry_max_backoff_secs, 8);
        assert_eq!(config.shell_timeout_secs, 300);
    }

    #[test]
    fn retry_env_overrides_apply() {
        // Save original env values
        let original_max = std::env::var("RECURSIVE_RETRY_MAX");
        let original_initial = std::env::var("RECURSIVE_RETRY_INITIAL_BACKOFF_SECS");
        let original_max_backoff = std::env::var("RECURSIVE_RETRY_MAX_BACKOFF_SECS");

        // Set custom values
        std::env::set_var("RECURSIVE_RETRY_MAX", "5");
        std::env::set_var("RECURSIVE_RETRY_INITIAL_BACKOFF_SECS", "2");
        std::env::set_var("RECURSIVE_RETRY_MAX_BACKOFF_SECS", "30");

        // We need to also set required env vars to avoid errors
        std::env::set_var("RECURSIVE_MODEL", "test-model");
        std::env::set_var("RECURSIVE_API_KEY", "test-key");

        let config = Config::from_env().unwrap();

        assert_eq!(config.retry_max, 5);
        assert_eq!(config.retry_initial_backoff_secs, 2);
        assert_eq!(config.retry_max_backoff_secs, 30);

        // Restore original env values
        std::env::remove_var("RECURSIVE_RETRY_MAX");
        std::env::remove_var("RECURSIVE_RETRY_INITIAL_BACKOFF_SECS");
        std::env::remove_var("RECURSIVE_RETRY_MAX_BACKOFF_SECS");
        std::env::remove_var("RECURSIVE_MODEL");
        std::env::remove_var("RECURSIVE_API_KEY");

        if let Ok(v) = original_max {
            std::env::set_var("RECURSIVE_RETRY_MAX", v);
        }
        if let Ok(v) = original_initial {
            std::env::set_var("RECURSIVE_RETRY_INITIAL_BACKOFF_SECS", v);
        }
        if let Ok(v) = original_max_backoff {
            std::env::set_var("RECURSIVE_RETRY_MAX_BACKOFF_SECS", v);
        }
    }

    // NOTE: both shell_timeout_* checks live in ONE test on purpose.
    // `cargo test` runs tests in parallel threads and `set_var` /
    // `remove_var` are process-global, so splitting them creates a
    // race (one test sees the other's value). MiniMax's goal-23 run
    // burned 50 steps discovering this exact race; lesson recorded in
    // AGENTS.md section 5.
    #[test]
    fn shell_timeout_default_and_env_override() {
        let original = std::env::var("RECURSIVE_SHELL_TIMEOUT_SECS").ok();
        std::env::set_var("RECURSIVE_MODEL", "test-model");
        std::env::set_var("RECURSIVE_API_KEY", "test-key");

        std::env::remove_var("RECURSIVE_SHELL_TIMEOUT_SECS");
        let config = Config::from_env().unwrap();
        assert_eq!(config.shell_timeout_secs, 300);

        std::env::set_var("RECURSIVE_SHELL_TIMEOUT_SECS", "42");
        let config = Config::from_env().unwrap();
        assert_eq!(config.shell_timeout_secs, 42);

        if let Some(v) = original {
            std::env::set_var("RECURSIVE_SHELL_TIMEOUT_SECS", v);
        } else {
            std::env::remove_var("RECURSIVE_SHELL_TIMEOUT_SECS");
        }
    }

    // Tests for load_project_context
    #[test]
    fn test_a_load_project_context_with_small_file() {
        let tmp = tempfile::tempdir().expect("tempdir");
        let path = tmp.path().join("AGENTS.md");
        std::fs::write(&path, "# Project Context\n\nHello world").expect("write");

        let content = load_project_context(tmp.path());
        assert!(content.is_some());
        assert!(content.unwrap().contains("Hello world"));
    }

    #[test]
    fn test_b_load_project_context_truncates_large_file() {
        let tmp = tempfile::tempdir().expect("tempdir");
        let path = tmp.path().join("AGENTS.md");
        // Write 20 KB of content
        let large_content = "x".repeat(20 * 1024);
        std::fs::write(&path, large_content).expect("write");

        let content = load_project_context(tmp.path());
        assert!(content.is_some());
        let c = content.unwrap();
        // Should contain truncation marker
        assert!(c.contains("truncated"));
        assert!(c.contains("20 KB"));
    }

    #[test]
    fn test_c_load_project_context_none_when_missing() {
        let tmp = tempfile::tempdir().expect("tempdir");
        // No AGENTS.md file
        let content = load_project_context(tmp.path());
        assert!(content.is_none());
    }
}