//! Integration tests for stdio transport
//!
//! These tests spawn the actual mocker binary and communicate via stdin/stdout
//! to verify end-to-end behavior including the "help" message feature.

use serde_json::{json, Value};
use std::process::Stdio;
use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
use tokio::process::Command;

/// Path to the mocker binary (debug build)
fn mocker_binary() -> std::path::PathBuf {
    let manifest_dir = env!("CARGO_MANIFEST_DIR");
    std::path::Path::new(manifest_dir)
        .parent()
        .unwrap()
        .parent()
        .unwrap()
        .join("target")
        .join("debug")
        .join(if cfg!(windows) {
            "dirigate.exe"
        } else {
            "dirigate"
        })
}

/// Path to the basic fixture file
fn fixture_path() -> std::path::PathBuf {
    let manifest_dir = env!("CARGO_MANIFEST_DIR");
    std::path::Path::new(manifest_dir)
        .join("examples")
        .join("basic.yaml")
}

/// Helper to send a JSON-RPC request and read the response
/// Skips any session/update notifications and returns only the response matching the request ID
async fn send_request(
    stdin: &mut tokio::process::ChildStdin,
    stdout: &mut BufReader<tokio::process::ChildStdout>,
    request: Value,
) -> anyhow::Result<Value> {
    // Send request
    let request_json = serde_json::to_string(&request)?;
    let request_id = request.get("id").cloned();
    stdin.write_all(request_json.as_bytes()).await?;
    stdin.write_all(b"\n").await?;
    stdin.flush().await?;

    // Read response, skipping notifications
    loop {
        let mut line = String::new();
        stdout.read_line(&mut line).await?;

        // Parse the message
        let msg: Value = match serde_json::from_str(line.trim()) {
            Ok(v) => v,
            Err(e) => {
                eprintln!("Failed to parse line: {}", line.trim());
                eprintln!("Error: {}", e);
                return Err(e.into());
            }
        };

        // Skip notifications (they have "method" but no "id")
        if msg.get("method").is_some() && msg.get("id").is_none() {
            continue;
        }

        // Check if this is the response we're looking for
        if let Some(id) = request_id.as_ref() {
            if msg.get("id") == Some(id) {
                return Ok(msg);
            }
        } else {
            // No ID means we're looking for any response
            return Ok(msg);
        }
    }
}

#[tokio::test]
async fn test_stdio_basic_flow() -> anyhow::Result<()> {
    let binary = mocker_binary();
    if !binary.exists() {
        eprintln!(
            "Mocker binary not found at {:?}. Run 'cargo build' first.",
            binary
        );
        return Ok(()); // Skip test if binary doesn't exist
    }

    let fixture = fixture_path();
    assert!(fixture.exists(), "Fixture file not found: {:?}", fixture);

    // Spawn the mocker process
    let mut child = Command::new(&binary)
        .args(&["serve", "--fixtures", fixture.to_str().unwrap(), "--stdio"])
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(Stdio::null()) // Suppress logs for cleaner test output
        .spawn()?;

    let mut stdin = child.stdin.take().expect("Failed to open stdin");
    let stdout = child.stdout.take().expect("Failed to open stdout");
    let mut stdout = BufReader::new(stdout);

    // Test 1: Initialize
    let init_request = json!({
        "jsonrpc": "2.0",
        "method": "initialize",
        "id": 1,
        "params": {
            "protocolVersion": 1,
            "clientCapabilities": {}
        }
    });

    let init_response = send_request(&mut stdin, &mut stdout, init_request).await?;
    assert_eq!(init_response["jsonrpc"], "2.0");
    assert_eq!(init_response["id"], 1);
    assert!(init_response["result"]["protocolVersion"].is_number());
    assert!(init_response["result"]["agentCapabilities"].is_object());

    // Test 2: Create session
    let session_request = json!({
        "jsonrpc": "2.0",
        "method": "session/new",
        "id": 2,
        "params": {
            "cwd": ".",
            "mcpServers": []
        }
    });

    let session_response = send_request(&mut stdin, &mut stdout, session_request).await?;
    assert_eq!(session_response["jsonrpc"], "2.0");
    assert_eq!(session_response["id"], 2);
    let session_id = session_response["result"]["sessionId"]
        .as_str()
        .expect("sessionId should be a string");
    assert!(!session_id.is_empty());

    // Test 3: Send a prompt
    let prompt_request = json!({
        "jsonrpc": "2.0",
        "method": "session/prompt",
        "id": 3,
        "params": {
            "sessionId": session_id,
            "prompt": [
                {
                    "type": "text",
                    "text": "hello world"
                }
            ]
        }
    });

    let prompt_response = send_request(&mut stdin, &mut stdout, prompt_request).await?;
    assert_eq!(prompt_response["jsonrpc"], "2.0");
    assert_eq!(prompt_response["id"], 3);
    assert!(prompt_response["result"]["stopReason"].is_string());

    // Clean up
    child.kill().await?;

    Ok(())
}

#[tokio::test]
async fn test_stdio_help_message() -> anyhow::Result<()> {
    let binary = mocker_binary();
    if !binary.exists() {
        eprintln!(
            "Mocker binary not found at {:?}. Run 'cargo build' first.",
            binary
        );
        return Ok(()); // Skip test if binary doesn't exist
    }

    let fixture = fixture_path();
    assert!(fixture.exists(), "Fixture file not found: {:?}", fixture);

    // Spawn the mocker process with stderr redirected to a temp file so we can read it
    let stderr_path = std::env::temp_dir().join("mocker_stderr.log");
    let stderr_file = std::fs::File::create(&stderr_path)?;

    let mut child = Command::new(&binary)
        .args(&["serve", "--fixtures", fixture.to_str().unwrap(), "--stdio"])
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(stderr_file) // Write to file
        .spawn()?;

    let mut stdin = child.stdin.take().expect("Failed to open stdin");
    let stdout = child.stdout.take().expect("Failed to open stdout");
    let mut stdout = BufReader::new(stdout);

    // Initialize
    let init_response = send_request(
        &mut stdin,
        &mut stdout,
        json!({
            "jsonrpc": "2.0",
            "method": "initialize",
            "id": 1,
            "params": {
                "protocolVersion": 1,
                "clientCapabilities": {}
            }
        }),
    )
    .await?;
    assert!(init_response["result"].is_object());

    // Create session
    let session_response = send_request(
        &mut stdin,
        &mut stdout,
        json!({
            "jsonrpc": "2.0",
            "method": "session/new",
            "id": 2,
            "params": {
                "cwd": ".",
                "mcpServers": []
            }
        }),
    )
    .await?;
    let session_id = session_response["result"]["sessionId"]
        .as_str()
        .expect("sessionId should be a string")
        .to_string(); // Store as owned string

    eprintln!("Created session: {}", session_id);

    // Send "help" message - now we have the session ID from THIS process
    let help_request = json!({
        "jsonrpc": "2.0",
        "method": "session/prompt",
        "id": 3,
        "params": {
            "sessionId": session_id,
            "prompt": [
                {
                    "type": "text",
                    "text": "help"
                }
            ]
        }
    });

    // Write the request
    let request_json = serde_json::to_string(&help_request)?;
    eprintln!("Sending help request: {}", request_json);
    stdin.write_all(request_json.as_bytes()).await?;
    stdin.write_all(b"\n").await?;
    stdin.flush().await?;
    eprintln!("Request sent and flushed");

    // Read the response AND the session/update notifications (streaming mode)
    let mut help_content = String::new();
    let mut response_received = false;
    let mut notifications_count = 0;

    // With streaming enabled, we'll receive multiple session/update notifications
    // and then finally the response with stopReason
    // Read up to 200 lines to capture all chunks (with 10 second total timeout)
    let start = std::time::Instant::now();
    while start.elapsed() < std::time::Duration::from_secs(10) {
        let mut line = String::new();
        match tokio::time::timeout(
            std::time::Duration::from_millis(100),
            stdout.read_line(&mut line),
        )
        .await
        {
            Ok(Ok(0)) => {
                eprintln!("Got EOF");
                break;
            }
            Ok(Ok(_)) => {
                eprintln!("Received line: {}", line.trim());
                let msg: Value = match serde_json::from_str(line.trim()) {
                    Ok(v) => v,
                    Err(e) => {
                        eprintln!("Failed to parse JSON: {}", e);
                        continue;
                    }
                };

                // Check if this is the response
                if msg.get("id") == Some(&json!(3)) {
                    eprintln!("Got response!");
                    assert_eq!(msg["jsonrpc"], "2.0");
                    assert!(msg["result"]["stopReason"].is_string());
                    response_received = true;
                    break; // Response is the last message
                }

                // Check if this is a session/update notification (streaming chunk)
                if msg.get("method") == Some(&json!("session/update")) {
                    eprintln!("Got session/update notification #{}", notifications_count + 1);
                    notifications_count += 1;
                    let params = &msg["params"];
                    if let Some(update) = params.get("update") {
                        if let Some(content) = update.get("content") {
                            if let Some(text) = content.get("text") {
                                help_content.push_str(text.as_str().unwrap_or(""));
                            }
                        }
                    }
                }
            }
            Err(_) => {
                // Timeout - if we have content and response, we're done
                if response_received {
                    break;
                }
                // Otherwise keep trying
            }
            Ok(Err(_)) => break, // Read error
        }
    }

    assert!(
        response_received,
        "Should receive response to help request (got {} notifications)",
        notifications_count
    );
    assert!(
        !help_content.is_empty(),
        "Should receive help content via notifications"
    );
    // Note: streaming may break words across chunks, so check for partial matches
    assert!(
        help_content.contains("ACP Mocker") || help_content.contains("ACPMocker"),
        "Help content should contain 'ACP Mocker'. Got: {}",
        help_content
    );
    assert!(
        help_content.contains("Diagnostics"),
        "Help content should contain 'Diagnostics'"
    );
    assert!(
        help_content.contains("Configuration") || help_content.contains("CurrentConfiguration"),
        "Help content should contain configuration section"
    );
    assert!(
        help_content.contains("Available") && help_content.contains("Methods"),
        "Help content should contain methods list"
    );

    // Clean up
    child.kill().await?;

    // Print stderr for debugging
    eprintln!("\n=== Mocker stderr log ===");
    if let Ok(log_content) = std::fs::read_to_string(&stderr_path) {
        eprintln!("{}", log_content);
    }
    eprintln!("=== End stderr log ===\n");

    Ok(())
}

#[tokio::test]
async fn test_stdio_session_not_found() -> anyhow::Result<()> {
    let binary = mocker_binary();
    if !binary.exists() {
        return Ok(());
    }

    let fixture = fixture_path();
    assert!(fixture.exists());

    let mut child = Command::new(&binary)
        .args(&["serve", "--fixtures", fixture.to_str().unwrap(), "--stdio"])
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(Stdio::null())
        .spawn()?;

    let mut stdin = child.stdin.take().unwrap();
    let stdout = child.stdout.take().unwrap();
    let mut stdout = BufReader::new(stdout);

    // Initialize
    send_request(
        &mut stdin,
        &mut stdout,
        json!({
            "jsonrpc": "2.0",
            "method": "initialize",
            "id": 1,
            "params": {
                "protocolVersion": 1,
                "clientCapabilities": {}
            }
        }),
    )
    .await?;

    // Try to use a non-existent session
    let error_response = send_request(
        &mut stdin,
        &mut stdout,
        json!({
            "jsonrpc": "2.0",
            "method": "session/prompt",
            "id": 2,
            "params": {
                "sessionId": "non-existent-session-id",
                "prompt": [
                    {
                        "type": "text",
                        "text": "hello"
                    }
                ]
            }
        }),
    )
    .await?;

    // Should get an error response
    assert_eq!(error_response["jsonrpc"], "2.0");
    assert_eq!(error_response["id"], 2);
    assert!(error_response["error"].is_object());
    assert!(error_response["error"]["message"]
        .as_str()
        .unwrap()
        .contains("Session not found"));

    child.kill().await?;

    Ok(())
}