// Agent definitions: self-contained JSON files with query + prompt.
//
// Each agent is a .json file in the agents/ directory containing:
//   - query: pipeline expression for node selection
//   - prompt: the full prompt template with {{TOPOLOGY}} and {{NODES}} placeholders
//   - model, schedule metadata
//
// This replaces the hardcoded per-agent node selection in prompts.rs.
// Agents that need custom generators or formatters (separator, split)
// stay in prompts.rs until the pipeline can express their logic.

use crate::neuro::{consolidation_priority, ReplayItem};
use crate::search;
use crate::store::Store;

use serde::Deserialize;

use std::path::PathBuf;

/// Agent definition: config (from JSON header) + prompt (raw markdown body).
#[derive(Clone, Debug)]
pub struct AgentDef {
    pub agent: String,
    pub query: String,
    pub prompt: String,
    pub model: String,
    pub schedule: String,
}

/// The JSON header portion (first line of the file).
#[derive(Deserialize)]
struct AgentHeader {
    agent: String,
    query: String,
    #[serde(default = "default_model")]
    model: String,
    #[serde(default)]
    schedule: String,
}

fn default_model() -> String { "sonnet".into() }

/// Parse an agent file: first line is JSON config, rest is the prompt.
fn parse_agent_file(content: &str) -> Option<AgentDef> {
    let (header_str, prompt) = content.split_once("\n\n")?;
    let header: AgentHeader = serde_json::from_str(header_str.trim()).ok()?;
    Some(AgentDef {
        agent: header.agent,
        query: header.query,
        prompt: prompt.to_string(),
        model: header.model,
        schedule: header.schedule,
    })
}

fn agents_dir() -> PathBuf {
    let repo = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("agents");
    if repo.is_dir() { return repo; }
    crate::store::memory_dir().join("agents")
}

/// Load all agent definitions.
pub fn load_defs() -> Vec<AgentDef> {
    let dir = agents_dir();
    let Ok(entries) = std::fs::read_dir(&dir) else { return Vec::new() };

    entries
        .filter_map(|e| e.ok())
        .filter(|e| {
            let p = e.path();
            p.extension().map(|x| x == "agent" || x == "md").unwrap_or(false)
        })
        .filter_map(|e| {
            let content = std::fs::read_to_string(e.path()).ok()?;
            parse_agent_file(&content)
        })
        .collect()
}

/// Look up a single agent definition by name.
pub fn get_def(name: &str) -> Option<AgentDef> {
    let dir = agents_dir();
    // Try both extensions
    for ext in ["agent", "md"] {
        let path = dir.join(format!("{}.{}", name, ext));
        if let Ok(content) = std::fs::read_to_string(&path) {
            if let Some(def) = parse_agent_file(&content) {
                return Some(def);
            }
        }
    }
    load_defs().into_iter().find(|d| d.agent == name)
}

/// Run a config-driven agent: query → format → fill prompt template.
pub fn run_agent(
    store: &Store,
    def: &AgentDef,
    count: usize,
) -> Result<super::prompts::AgentBatch, String> {
    let graph = store.build_graph();

    // Parse and run the query pipeline
    let mut stages = search::Stage::parse_pipeline(&def.query)?;

    let has_limit = stages.iter().any(|s| matches!(s, search::Stage::Transform(search::Transform::Limit(_))));
    if !has_limit {
        stages.push(search::Stage::Transform(search::Transform::Limit(count)));
    }

    let results = search::run_query(&stages, vec![], &graph, store, false, count);

    if results.is_empty() {
        return Err(format!("{}: query returned no results", def.agent));
    }

    let keys: Vec<String> = results.iter().map(|(k, _)| k.clone()).collect();
    let items: Vec<ReplayItem> = keys_to_replay_items(store, &keys, &graph);

    // Fill placeholders in the embedded prompt
    let topology = super::prompts::format_topology_header_pub(&graph);
    let nodes_section = super::prompts::format_nodes_section_pub(store, &items, &graph);

    let prompt = def.prompt
        .replace("{{TOPOLOGY}}", &topology)
        .replace("{{NODES}}", &nodes_section)
        .replace("{{EPISODES}}", &nodes_section);

    Ok(super::prompts::AgentBatch { prompt, node_keys: keys })
}

/// Convert a list of keys to ReplayItems with priority and graph metrics.
pub fn keys_to_replay_items(
    store: &Store,
    keys: &[String],
    graph: &crate::graph::Graph,
) -> Vec<ReplayItem> {
    keys.iter()
        .filter_map(|key| {
            let node = store.nodes.get(key)?;
            let priority = consolidation_priority(store, key, graph, None);
            let cc = graph.clustering_coefficient(key);

            Some(ReplayItem {
                key: key.clone(),
                priority,
                interval_days: node.spaced_repetition_interval,
                emotion: node.emotion,
                cc,
                classification: "unknown",
                outlier_score: 0.0,
            })
        })
        .collect()
}