agentwerk 0.1.2

//! Prompt infrastructure: behavior defaults, context building, and constants.

use std::collections::HashMap;
use std::path::Path;

use serde_json::Value;


// ---------------------------------------------------------------------------
// Behavior prompts
// ---------------------------------------------------------------------------

/// Default behavioral directives appended to the system prompt after the
/// identity prompt. Override with [`Agent::behavior_prompt()`].
pub const DEFAULT_BEHAVIOR_PROMPT: &str = "\
# Task execution
- Do not propose changes to files you have not read. Read first, then modify.
- Do not add features or improvements beyond what was asked.
- Do not create files unless absolutely necessary. Prefer editing existing files.
- If an approach fails, diagnose why before switching tactics.

# Tool usage
- Do NOT use bash when a dedicated tool exists (read_file over cat, edit_file over sed, grep over rg, glob over find).
- Call multiple tools in a single response. Make independent calls in parallel.
- If tool calls depend on previous results, call them sequentially — do not guess parameters.

# Safety concerns
- Consider the reversibility and impact of actions before executing them.
- Prefer reversible operations over destructive ones when both achieve the goal.
- If an approach fails, diagnose the root cause before retrying or switching tactics.

# Communication
- Be direct. Lead with the answer or action, not the reasoning.
- Keep output concise — omit filler, preamble, and unnecessary transitions.
- Try the simplest approach first.";

// ---------------------------------------------------------------------------
// Structured output constants
// ---------------------------------------------------------------------------

pub(crate) const STRUCTURED_OUTPUT_INSTRUCTION: &str =
    "\n\nIMPORTANT: You must provide your final response using the StructuredOutput tool \
     with the required structured format. After using any other tools needed to complete \
     the task, always call StructuredOutput with your final answer in the specified schema.";

pub(crate) const STRUCTURED_OUTPUT_RETRY: &str =
    "You MUST call the StructuredOutput tool to complete \
     this request. Call this tool now with the required schema.";

pub(crate) const STRUCTURED_OUTPUT_TOOL_DESCRIPTION: &str =
    "Return your final response using the required output schema. \
     Call this tool exactly once at the end to provide the structured result.";

pub(crate) const STRUCTURED_OUTPUT_TOOL_NAME: &str = "StructuredOutput";

// ---------------------------------------------------------------------------
// Template interpolation
// ---------------------------------------------------------------------------

/// Replace {key} placeholders in a template with values from state.
pub(crate) fn interpolate(template: &str, state: &HashMap<String, Value>) -> String {
    let mut result = template.to_string();
    for (key, value) in state {
        let replacement = match value {
            Value::String(s) => s.clone(),
            other => other.to_string(),
        };
        result = result.replace(&format!("{{{key}}}"), &replacement);
    }
    result
}

// ---------------------------------------------------------------------------
// Environment prompt
// ---------------------------------------------------------------------------

/// Build the metadata block — working directory, platform, OS version, and
/// current date. Prepended to the first user message.
pub(crate) fn collect_metadata(cwd: &Path) -> String {
    let working_directory = cwd.display();
    let platform = std::env::consts::OS;
    let os_version = std::process::Command::new("uname")
        .arg("-r")
        .output()
        .map(|o| String::from_utf8_lossy(&o.stdout).trim().to_string())
        .unwrap_or_default();
    let date = format_current_date();

    format!(
        "<environment>\nWorking directory: {working_directory}\nPlatform: {platform}\nOS version: {os_version}\nDate: {date}\n</environment>"
    )
}

// ---------------------------------------------------------------------------
// Private helpers
// ---------------------------------------------------------------------------

/// Convert epoch seconds to a date string using the civil-from-days algorithm.
/// http://howardhinnant.github.io/date_algorithms.html
fn format_current_date() -> String {
    let epoch_secs = std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .unwrap_or_default()
        .as_secs();

    let days = epoch_secs / 86400;
    let z = days + 719468;
    let era = z / 146097;
    let doe = z - era * 146097;
    let yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
    let year = yoe + era * 400;
    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
    let mp = (5 * doy + 2) / 153;
    let day = doy - (153 * mp + 2) / 5 + 1;
    let month = if mp < 10 { mp + 3 } else { mp - 9 };
    let year = if month <= 2 { year + 1 } else { year };

    format!("{year:04}-{month:02}-{day:02}")
}

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

    #[test]
    fn metadata_includes_path() {
        let ctx = collect_metadata(std::path::Path::new("/home/user/project"));
        assert!(ctx.contains("/home/user/project"));
        assert!(ctx.contains("<environment>"));
    }

    #[test]
    fn interpolate_substitutes_placeholders() {
        let mut vars: HashMap<String, Value> = HashMap::new();
        vars.insert("name".into(), Value::String("Alice".into()));
        vars.insert("count".into(), Value::from(3));
        let out = interpolate("Hello {name}, you have {count} tasks.", &vars);
        assert_eq!(out, "Hello Alice, you have 3 tasks.");
    }
}