//! Sequential thinking tool — step-by-step reasoning.
//!
//! Allows the agent to record one step of a chain-of-thought reasoning process,
//! tracking progress through a planned number of steps.

use crate::tools::{Tool, ToolCtx};
use anyhow::Result;
use serde_json::{json, Value};
use tracing::{info, instrument};

/// Perform sequential / step-by-step reasoning (chain-of-thought).
///
/// Flow: extract thought, step number, total steps, and continuation flag from
/// args → format into a reasoning step response.
pub struct SeqThink;

impl Tool for SeqThink {
    fn name(&self) -> &'static str {
        "sequential_think"
    }

    fn description(&self) -> &'static str {
        "Perform sequential / step-by-step reasoning (chain-of-thought)"
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "thought": {
                    "type": "string",
                    "description": "The current step of reasoning"
                },
                "step_number": {
                    "type": "integer",
                    "description": "Current step number"
                },
                "total_steps": {
                    "type": "integer",
                    "description": "Total number of steps planned"
                },
                "next_thought_needed": {
                    "type": "boolean",
                    "description": "Whether another thinking step is needed"
                }
            },
            "required": ["thought"]
        })
    }

    #[instrument(skip(self, _ctx, args))]
    fn run(&self, _ctx: &ToolCtx, args: &Value) -> Result<String> {
        let thought = crate::tools::arg_str(args, "thought")?;
        let step = args
            .get("step_number")
            .and_then(|v| v.as_i64())
            .unwrap_or(0);
        let total = args
            .get("total_steps")
            .and_then(|v| v.as_i64())
            .unwrap_or(1);
        let next_needed = args
            .get("next_thought_needed")
            .and_then(|v| v.as_bool())
            .unwrap_or(false);

        info!(step, total, next_needed, "sequential think step");

        Ok(format!(
            "Step {}/{}: {}\n{}",
            step,
            total,
            thought,
            if next_needed {
                "Continuing reasoning..."
            } else {
                "Reasoning complete."
            }
        ))
    }
}