use async_trait::async_trait;
use serde_json::Value;
use tracing::{debug, info};
use std::time::Instant;

use crate::flow::task::Executor;
use crate::flow::domain::{NodeDef, NodeId};

fn read_node_script_file(ctx: &Value, node_id: &str, lang_key: &str) -> Option<String> {
    if let Some(nodes) = ctx.get("nodes").and_then(|v| v.as_object()) {
        if let Some(m) = nodes.get(node_id).and_then(|v| v.get("scripts")).and_then(|v| v.as_object()) {
            return m.get(lang_key).and_then(|v| v.as_str()).map(|s| s.to_string());
        }
    }
    None
}

fn truncate_str(s: &str, max: usize) -> String {
    let s = s.replace('\n', " ").replace('\r', " ");
    if s.len() <= max { s } else { format!("{}…", &s[..max]) }
}

#[derive(Default)]
pub struct ScriptJsTask;

#[async_trait]
impl Executor for ScriptJsTask {
    async fn execute(&self, node_id: &NodeId, _node: &NodeDef, ctx: &mut Value) -> anyhow::Result<()> {
        let start = Instant::now();

        // 优先 nodes.<id>.scripts.js 指定的脚本文件路径
        if let Some(path) = read_node_script_file(ctx, &node_id.0, "js") {
            let preview = truncate_str(&path, 120);
            info!(target = "udmin.flow", node=%node_id.0, file=%preview, "script_js task: JavaScript file execution not implemented yet (skipped)");
            return Ok(());
        }

        // 兼容 inline 配置（暂不执行，仅提示）
        let inline = ctx.get("script")
            .or_else(|| ctx.get("expr"))
            .and_then(|v| v.as_str())
            .map(|s| s.to_string());
        if let Some(code) = inline {
            let preview = truncate_str(&code, 200);
            debug!(target = "udmin.flow", node=%node_id.0, preview=%preview, "script_js task: inline script provided, but execution not implemented");
            let _elapsed = start.elapsed().as_millis();
            info!(target = "udmin.flow", node=%node_id.0, "script_js task: JavaScript execution not implemented yet (skipped)");
            return Ok(());
        }

        info!(target = "udmin.flow", node=%node_id.0, "script_js task: no script found, skip");
        Ok(())
    }
}