//! End-to-end integration tests for aether-recall-mcp.
//!
//! Spawns the actual binary, talks JSON-RPC over stdio, verifies
//! the round-trip and the canonical-form abstraction.

use serde_json::json;
use std::io::{Read, Write};
use std::path::PathBuf;
use std::process::{Child, Command, Stdio};

fn binary_path() -> PathBuf {
    PathBuf::from(env!("CARGO_BIN_EXE_aether-recall-mcp"))
}

struct Mcp {
    child: Child,
}

impl Mcp {
    fn spawn(data_dir: &PathBuf) -> Self {
        let mut cmd = Command::new(binary_path());
        cmd.env("AETHER_RECALL_DIR", data_dir)
            .stdin(Stdio::piped())
            .stdout(Stdio::piped())
            .stderr(Stdio::piped());
        let child = cmd.spawn().expect("spawn aether-recall-mcp");
        Self { child }
    }

    fn send(&mut self, req: serde_json::Value) -> serde_json::Value {
        let stdin = self.child.stdin.as_mut().expect("stdin");
        let s = serde_json::to_string(&req).unwrap();
        writeln!(stdin, "{}", s).unwrap();
        stdin.flush().unwrap();

        let stdout = self.child.stdout.as_mut().expect("stdout");
        let mut buf = Vec::new();
        let mut byte = [0u8; 1];
        while stdout.read(&mut byte).unwrap() > 0 {
            buf.push(byte[0]);
            if byte[0] == b'\n' { break; }
        }
        serde_json::from_slice(&buf).unwrap()
    }
}

impl Drop for Mcp {
    fn drop(&mut self) {
        let _ = self.child.kill();
    }
}

#[test]
fn full_lifecycle() {
    let dir = tempdir_in("/tmp");
    let mut m = Mcp::spawn(&dir);

    // 1. initialize
    let r = m.send(json!({"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}));
    assert_eq!(r["result"]["serverInfo"]["name"], "aether-recall");

    // 2. cold lookup → miss
    let r = m.send(json!({
        "jsonrpc":"2.0","id":2,"method":"tools/call",
        "params":{"name":"lookup_resolution","arguments":{"failure":"error[E0308]: expected i32, found &str"}}
    }));
    let content = r["result"]["content"][0]["text"].as_str().unwrap();
    assert!(content.contains("\"hit\":false"), "got: {content}");

    // 3. record_outcome
    let r = m.send(json!({
        "jsonrpc":"2.0","id":3,"method":"tools/call",
        "params":{"name":"record_outcome","arguments":{"failure":"error[E0308]: expected i32, found &str","resolution":"use .to_string()","worked":true}}
    }));
    let content = r["result"]["content"][0]["text"].as_str().unwrap();
    assert!(content.contains("\"recorded\":true"));

    // 4. warm lookup → hit
    let r = m.send(json!({
        "jsonrpc":"2.0","id":4,"method":"tools/call",
        "params":{"name":"lookup_resolution","arguments":{"failure":"error[E0308]: expected i32, found &str"}}
    }));
    let content = r["result"]["content"][0]["text"].as_str().unwrap();
    assert!(content.contains("\"hit\":true"), "got: {content}");
    assert!(content.contains("use .to_string()"), "got: {content}");

    // 5. path-equivalent surface form → hit (canonical abstraction)
    let r = m.send(json!({
        "jsonrpc":"2.0","id":5,"method":"tools/call",
        "params":{"name":"lookup_resolution","arguments":{"failure":"error[E0308]: expected i32, found &str\n   --> src/foo.rs:42:5"}}
    }));
    let content = r["result"]["content"][0]["text"].as_str().unwrap();
    assert!(content.contains("\"hit\":true"), "got: {content}");

    // 6. memory_stats: 3 lookups, 2 hits, 1 miss
    let r = m.send(json!({
        "jsonrpc":"2.0","id":6,"method":"tools/call",
        "params":{"name":"memory_stats","arguments":{}}
    }));
    let content = r["result"]["content"][0]["text"].as_str().unwrap();
    assert!(content.contains("\"lookups\":3"));
    assert!(content.contains("\"hits\":2"));
    assert!(content.contains("\"misses\":1"));
    assert!(content.contains("\"hit_rate\":0.6"));

    // 7. compact succeeds
    let r = m.send(json!({
        "jsonrpc":"2.0","id":7,"method":"tools/call",
        "params":{"name":"compact","arguments":{}}
    }));
    let content = r["result"]["content"][0]["text"].as_str().unwrap();
    assert!(content.contains("\"compacted\":true"));

    // 8. error: empty failure
    let r = m.send(json!({
        "jsonrpc":"2.0","id":8,"method":"tools/call",
        "params":{"name":"lookup_resolution","arguments":{"failure":""}}
    }));
    assert_eq!(r["result"]["isError"], true);
    let content = r["result"]["content"][0]["text"].as_str().unwrap();
    assert!(content.contains("\"tool\":\"lookup_resolution\""));
}

fn tempdir_in(parent: &str) -> PathBuf {
    use std::time::{SystemTime, UNIX_EPOCH};
    let stamp = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().as_nanos();
    let p = PathBuf::from(parent).join(format!("aether-recall-mcp-it-{}", stamp));
    std::fs::create_dir_all(&p).unwrap();
    p
}