//! Integration test for CAN Sync v2
//!
//! Starts two CAN service instances + two sync agents, ingests files on each
//! side, and verifies bidirectional sync.
//!
//! Usage:
//!   cargo run --bin sync-test
//!
//! Prerequisites:
//!   CAN service must be built: `cargo build` in the CanService root

use std::path::{Path, PathBuf};
use std::process::{Child, Command, Stdio};
use std::time::{Duration, Instant};

use rand::Rng;
use serde_json::Value;
use tempfile::TempDir;

// ── Configuration ────────────────────────────────────────────────────────

const CAN_A_PORT: u16 = 13210;
const CAN_B_PORT: u16 = 13220;
const SYNC_KEY: &str = "test-sync-key-42";
const SYNC_PASSPHRASE: &str = "integration-test-passphrase";
const SYNC_TIMEOUT: Duration = Duration::from_secs(60);
const POLL_INTERVAL: Duration = Duration::from_millis(500);

// ── Process management ───────────────────────────────────────────────────

struct ManagedProcess {
    child: Child,
    name: String,
}

impl ManagedProcess {
    fn spawn(
        name: &str,
        cmd: &str,
        args: &[&str],
        envs: &[(&str, &str)],
        log_dir: &Path,
    ) -> Self {
        println!("  Starting {} ...", name);
        let mut command = Command::new(cmd);

        let log_file = std::fs::File::create(log_dir.join(format!("{}.log", name)))
            .expect("create log file");
        let log_file_clone = log_file.try_clone().expect("clone log file handle");
        command
            .args(args)
            .stdout(Stdio::from(log_file))
            .stderr(Stdio::from(log_file_clone))
            .env("RUST_LOG", "can_sync=debug,can_service=debug,iroh=info,iroh_gossip=info");

        for (k, v) in envs {
            command.env(k, v);
        }
        let child = command
            .spawn()
            .unwrap_or_else(|e| panic!("Failed to start {}: {}", name, e));
        println!("  {} started (pid={})", name, child.id());
        Self {
            child,
            name: name.to_string(),
        }
    }

    fn kill(&mut self) {
        let _ = self.child.kill();
        let _ = self.child.wait();
        println!("  {} stopped", self.name);
    }
}

impl Drop for ManagedProcess {
    fn drop(&mut self) {
        self.kill();
    }
}

// ── Test harness ─────────────────────────────────────────────────────────

struct TestHarness {
    _can_a: ManagedProcess,
    _can_b: ManagedProcess,
    _sync_a: ManagedProcess,
    _sync_b: ManagedProcess,
    _tmp_a: TempDir,
    _tmp_b: TempDir,
    _tmp_sync_a: TempDir,
    _tmp_sync_b: TempDir,
    log_dir: TempDir,
    can_a_url: String,
    can_b_url: String,
}

impl TestHarness {
    fn new(can_service_bin: &Path) -> Self {
        println!("\n=== Setting up test harness ===\n");

        // Create temp directories
        let tmp_a = TempDir::new().expect("create temp dir A");
        let tmp_b = TempDir::new().expect("create temp dir B");
        let tmp_sync_a = TempDir::new().expect("create temp dir sync A");
        let tmp_sync_b = TempDir::new().expect("create temp dir sync B");
        let log_dir = TempDir::new().expect("create log dir");

        println!("  Logs: {}", log_dir.path().display());
        println!("  CAN A storage: {}", tmp_a.path().display());
        println!("  CAN B storage: {}", tmp_b.path().display());

        // Write CAN service configs
        let config_a = tmp_a.path().join("config.yaml");
        let config_b = tmp_b.path().join("config.yaml");
        write_can_config(&config_a, tmp_a.path(), SYNC_KEY);
        write_can_config(&config_b, tmp_b.path(), SYNC_KEY);

        // Start CAN services
        let can_a = ManagedProcess::spawn(
            "CAN-A",
            can_service_bin.to_str().unwrap(),
            &[config_a.to_str().unwrap()],
            &[("CAN_PORT", &CAN_A_PORT.to_string())],
            log_dir.path(),
        );
        let can_b = ManagedProcess::spawn(
            "CAN-B",
            can_service_bin.to_str().unwrap(),
            &[config_b.to_str().unwrap()],
            &[("CAN_PORT", &CAN_B_PORT.to_string())],
            log_dir.path(),
        );

        let can_a_url = format!("http://127.0.0.1:{}", CAN_A_PORT);
        let can_b_url = format!("http://127.0.0.1:{}", CAN_B_PORT);

        // Wait for CAN services to be ready
        println!("\n  Waiting for CAN services to start...");
        wait_for_http(&can_a_url, Duration::from_secs(10), log_dir.path(), "CAN-A");
        wait_for_http(&can_b_url, Duration::from_secs(10), log_dir.path(), "CAN-B");
        println!("  Both CAN services ready!");

        // Find can-sync binary
        let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        let can_sync_bin = manifest_dir
            .join("target")
            .join("debug")
            .join("can-sync")
            .with_extension(std::env::consts::EXE_EXTENSION);
        assert!(
            can_sync_bin.exists(),
            "can-sync binary not found at {}",
            can_sync_bin.display()
        );
        println!("  Using can-sync: {}", can_sync_bin.display());

        // Ticket file paths for direct peer connection
        // Sync-A writes its addr, Sync-B reads it and connects directly
        let ticket_a = tmp_sync_a.path().join("ticket_a.json");
        let ticket_a_str = ticket_a.to_str().unwrap().replace('\\', "/");

        // Write sync agent configs with ticket file exchange
        let sync_config_a = tmp_sync_a.path().join("config.yaml");
        let sync_config_b = tmp_sync_b.path().join("config.yaml");

        // Sync-A: write its own ticket
        write_sync_config_with_tickets(
            &sync_config_a,
            &can_a_url,
            SYNC_KEY,
            SYNC_PASSPHRASE,
            Some(&ticket_a_str), // write our ticket here
            None,                // don't connect to anyone
        );

        // Sync-B: read Sync-A's ticket and connect directly
        write_sync_config_with_tickets(
            &sync_config_b,
            &can_b_url,
            SYNC_KEY,
            SYNC_PASSPHRASE,
            None,                // don't write our own ticket
            Some(&ticket_a_str), // connect to Sync-A using this ticket
        );

        // Start Sync-A first (it writes the ticket)
        let sync_a = ManagedProcess::spawn(
            "Sync-A",
            can_sync_bin.to_str().unwrap(),
            &[sync_config_a.to_str().unwrap()],
            &[],
            log_dir.path(),
        );

        // Wait for Sync-A to write its ticket file
        println!("  Waiting for Sync-A to write ticket...");
        let ticket_start = Instant::now();
        loop {
            if ticket_start.elapsed() > Duration::from_secs(15) {
                print_log(log_dir.path(), "Sync-A");
                panic!("Timeout waiting for Sync-A ticket file");
            }
            if let Ok(contents) = std::fs::read_to_string(&ticket_a) {
                if !contents.trim().is_empty() {
                    println!("  Sync-A ticket ready ({} bytes)", contents.len());
                    break;
                }
            }
            std::thread::sleep(Duration::from_millis(100));
        }

        // Start Sync-B (it will read Sync-A's ticket and connect)
        let sync_b = ManagedProcess::spawn(
            "Sync-B",
            can_sync_bin.to_str().unwrap(),
            &[sync_config_b.to_str().unwrap()],
            &[],
            log_dir.path(),
        );

        // Wait for peers to connect
        println!("  Waiting for sync agents to connect...");
        std::thread::sleep(Duration::from_secs(5));

        println!("  Test harness ready!\n");

        Self {
            _can_a: can_a,
            _can_b: can_b,
            _sync_a: sync_a,
            _sync_b: sync_b,
            _tmp_a: tmp_a,
            _tmp_b: tmp_b,
            _tmp_sync_a: tmp_sync_a,
            _tmp_sync_b: tmp_sync_b,
            log_dir,
            can_a_url,
            can_b_url,
        }
    }

    fn print_logs(&self) {
        println!("\n=== Process Logs ===");
        for name in &["Sync-A", "Sync-B", "CAN-A", "CAN-B"] {
            print_log(self.log_dir.path(), name);
        }
    }
}

// ── Config writers ───────────────────────────────────────────────────────

fn write_can_config(path: &Path, storage_root: &Path, sync_key: &str) {
    let storage_str = storage_root.to_str().unwrap().replace('\\', "/");
    let content = format!(
        r#"storage_root: "{}"
admin_token: "test-admin-token"
enable_thumbnail_cache: false
sync_api_key: "{}"
"#,
        storage_str, sync_key
    );
    std::fs::write(path, content).expect("write CAN config");
}

fn write_sync_config_with_tickets(
    path: &Path,
    can_url: &str,
    sync_key: &str,
    passphrase: &str,
    ticket_file: Option<&str>,
    connect_ticket_file: Option<&str>,
) {
    let mut content = format!(
        r#"can_service_url: "{}"
sync_api_key: "{}"
sync_passphrase: "{}"
poll_interval_secs: 2
"#,
        can_url, sync_key, passphrase
    );

    if let Some(tf) = ticket_file {
        content.push_str(&format!("ticket_file: \"{}\"\n", tf));
    }
    if let Some(ctf) = connect_ticket_file {
        content.push_str(&format!("connect_ticket_file: \"{}\"\n", ctf));
    }

    std::fs::write(path, content).expect("write sync config");
}

// ── Logging helpers ─────────────────────────────────────────────────────

fn print_log(log_dir: &Path, name: &str) {
    let log_path = log_dir.join(format!("{}.log", name));
    if let Ok(contents) = std::fs::read_to_string(&log_path) {
        let lines: Vec<&str> = contents.lines().collect();
        let show = if lines.len() > 50 { &lines[lines.len() - 50..] } else { &lines };
        println!("\n--- {} (last {} of {} lines) ---", name, show.len(), lines.len());
        for line in show {
            println!("  {}", line);
        }
    } else {
        println!("\n--- {} (no log file) ---", name);
    }
}

// ── HTTP helpers ─────────────────────────────────────────────────────────

fn wait_for_http(base_url: &str, timeout: Duration, log_dir: &Path, name: &str) {
    let client = reqwest::blocking::Client::new();
    let start = Instant::now();
    let url = format!("{}/api/v1/can/0/list?limit=1", base_url);

    loop {
        if start.elapsed() > timeout {
            print_log(log_dir, name);
            panic!("Timeout waiting for {} to become ready", base_url);
        }
        match client.get(&url).timeout(Duration::from_secs(1)).send() {
            Ok(resp) if resp.status().is_success() => return,
            _ => std::thread::sleep(Duration::from_millis(200)),
        }
    }
}

/// Ingest a file into a CAN service instance. Returns the asset hash.
fn ingest_file(base_url: &str, filename: &str, content: &[u8], mime_type: &str) -> String {
    let client = reqwest::blocking::Client::new();
    let url = format!("{}/api/v1/can/0/ingest", base_url);

    let part = reqwest::blocking::multipart::Part::bytes(content.to_vec())
        .file_name(filename.to_string())
        .mime_str(mime_type)
        .unwrap();

    let form = reqwest::blocking::multipart::Form::new()
        .part("file", part)
        .text("mime_type", mime_type.to_string());

    let resp = client
        .post(&url)
        .multipart(form)
        .send()
        .expect("ingest request failed");

    assert!(
        resp.status().is_success(),
        "Ingest failed with status {}",
        resp.status()
    );

    let body: Value = resp.json().expect("parse ingest response");
    body["data"]["hash"]
        .as_str()
        .expect("no hash in response")
        .to_string()
}

/// List all assets from a CAN service. Returns list of hashes.
fn list_hashes(base_url: &str) -> Vec<String> {
    let client = reqwest::blocking::Client::new();
    let url = format!("{}/api/v1/can/0/list?limit=1000", base_url);

    let resp = client
        .get(&url)
        .timeout(Duration::from_secs(5))
        .send()
        .expect("list request failed");

    if !resp.status().is_success() {
        return vec![];
    }

    let body: Value = resp.json().expect("parse list response");
    body["data"]["items"]
        .as_array()
        .unwrap_or(&vec![])
        .iter()
        .filter_map(|item| item["hash"].as_str().map(String::from))
        .collect()
}

/// Wait for a specific hash to appear on a CAN service.
fn wait_for_hash(base_url: &str, hash: &str, timeout: Duration) -> bool {
    let start = Instant::now();
    while start.elapsed() < timeout {
        let hashes = list_hashes(base_url);
        if hashes.contains(&hash.to_string()) {
            let elapsed = start.elapsed();
            println!("    (synced in {:.1}s)", elapsed.as_secs_f64());
            return true;
        }
        std::thread::sleep(POLL_INTERVAL);
    }
    false
}

/// Generate random file content of given size.
fn random_content(size: usize) -> Vec<u8> {
    let mut rng = rand::rng();
    let mut buf = vec![0u8; size];
    rng.fill(&mut buf[..]);
    buf
}

// ── Test runner ──────────────────────────────────────────────────────────

fn find_can_service_bin() -> PathBuf {
    let self_exe = std::env::current_exe().expect("get current exe path");
    let target_dir = self_exe.parent().unwrap();

    let bin_name = if cfg!(windows) {
        "can-service.exe"
    } else {
        "can-service"
    };

    // Check same directory
    let candidate = target_dir.join(bin_name);
    if candidate.exists() {
        return candidate;
    }

    // Check parent/debug
    let candidate = target_dir.parent().unwrap().join("debug").join(bin_name);
    if candidate.exists() {
        return candidate;
    }

    // Check workspace target/debug
    let workspace_root = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .parent()
        .unwrap()
        .parent()
        .unwrap()
        .to_path_buf();
    let candidate = workspace_root.join("target").join("debug").join(bin_name);
    if candidate.exists() {
        return candidate;
    }

    panic!(
        "Cannot find {} binary. Build it first:\n  cd {} && cargo build",
        bin_name,
        workspace_root.display()
    );
}

fn main() {
    println!("╔══════════════════════════════════════════╗");
    println!("║     CAN Sync v2 Integration Test         ║");
    println!("╚══════════════════════════════════════════╝");

    let can_service_bin = find_can_service_bin();
    println!("\nUsing CAN service: {}", can_service_bin.display());

    // Build can-sync if needed
    println!("\nBuilding can-sync...");
    let build_status = Command::new("cargo")
        .args(["build", "--bin", "can-sync"])
        .current_dir(env!("CARGO_MANIFEST_DIR"))
        .status()
        .expect("cargo build failed");
    assert!(build_status.success(), "Failed to build can-sync");

    // Set up harness (starts all processes)
    let harness = TestHarness::new(&can_service_bin);

    let mut passed = 0;
    let mut failed = 0;
    let mut results: Vec<(String, bool, String)> = vec![];

    // ── Test 1: Ingest on A → appears on B ───────────────────────────
    print_test_header("Test 1: Ingest file on CAN-A, verify sync to CAN-B");
    {
        let content = random_content(4096);
        let hash = ingest_file(&harness.can_a_url, "test1.bin", &content, "application/octet-stream");
        println!("  Ingested on A: hash={}", &hash[..16]);

        let found = wait_for_hash(&harness.can_b_url, &hash, SYNC_TIMEOUT);
        if found {
            println!("  ✓ File appeared on CAN-B!");
            results.push(("A→B sync".into(), true, format!("hash {}", &hash[..16])));
            passed += 1;
        } else {
            println!("  ✗ File NOT found on CAN-B after {:?}", SYNC_TIMEOUT);
            results.push(("A→B sync".into(), false, "timeout".into()));
            failed += 1;
        }
    }

    // ── Test 2: Ingest on B → appears on A ───────────────────────────
    print_test_header("Test 2: Ingest file on CAN-B, verify sync to CAN-A");
    {
        let content = random_content(8192);
        let hash = ingest_file(&harness.can_b_url, "test2.dat", &content, "application/octet-stream");
        println!("  Ingested on B: hash={}", &hash[..16]);

        let found = wait_for_hash(&harness.can_a_url, &hash, SYNC_TIMEOUT);
        if found {
            println!("  ✓ File appeared on CAN-A!");
            results.push(("B→A sync".into(), true, format!("hash {}", &hash[..16])));
            passed += 1;
        } else {
            println!("  ✗ File NOT found on CAN-A after {:?}", SYNC_TIMEOUT);
            results.push(("B→A sync".into(), false, "timeout".into()));
            failed += 1;
        }
    }

    // ── Test 3: Multiple files batch ─────────────────────────────────
    print_test_header("Test 3: Ingest 5 files on A, verify all sync to B");
    {
        let mut hashes = vec![];
        for i in 0..5 {
            let content = random_content(1024 + i * 512);
            let fname = format!("batch_{}.bin", i);
            let hash = ingest_file(&harness.can_a_url, &fname, &content, "application/octet-stream");
            println!("  Ingested batch file {}: hash={}", i, &hash[..16]);
            hashes.push(hash);
        }

        let mut all_found = true;
        for (i, hash) in hashes.iter().enumerate() {
            let found = wait_for_hash(&harness.can_b_url, hash, SYNC_TIMEOUT);
            if found {
                println!("  ✓ Batch file {} synced", i);
            } else {
                println!("  ✗ Batch file {} NOT synced", i);
                all_found = false;
            }
        }

        if all_found {
            results.push(("Batch A→B (5 files)".into(), true, "all synced".into()));
            passed += 1;
        } else {
            results.push(("Batch A→B (5 files)".into(), false, "some missing".into()));
            failed += 1;
        }
    }

    // ── Test 4: Verify total counts match ────────────────────────────
    print_test_header("Test 4: Verify asset counts match on both sides");
    {
        std::thread::sleep(Duration::from_secs(5));

        let a_hashes = list_hashes(&harness.can_a_url);
        let b_hashes = list_hashes(&harness.can_b_url);

        println!("  CAN-A has {} assets", a_hashes.len());
        println!("  CAN-B has {} assets", b_hashes.len());

        if a_hashes.len() == b_hashes.len() {
            let a_set: std::collections::HashSet<_> = a_hashes.iter().collect();
            let b_set: std::collections::HashSet<_> = b_hashes.iter().collect();
            let matching = a_set == b_set;

            if matching {
                println!("  ✓ Both sides have identical asset sets ({} assets)", a_hashes.len());
                results.push(("Count match".into(), true, format!("{} == {}", a_hashes.len(), b_hashes.len())));
                passed += 1;
            } else {
                println!("  ✗ Same count but different hashes!");
                let only_a: Vec<_> = a_set.difference(&b_set).collect();
                let only_b: Vec<_> = b_set.difference(&a_set).collect();
                if !only_a.is_empty() {
                    println!("    Only on A: {:?}", only_a.iter().map(|h| &h[..16]).collect::<Vec<_>>());
                }
                if !only_b.is_empty() {
                    println!("    Only on B: {:?}", only_b.iter().map(|h| &h[..16]).collect::<Vec<_>>());
                }
                results.push(("Count match".into(), false, "hash mismatch".into()));
                failed += 1;
            }
        } else {
            println!("  ✗ Count mismatch: A={}, B={}", a_hashes.len(), b_hashes.len());
            results.push(("Count match".into(), false, format!("{} != {}", a_hashes.len(), b_hashes.len())));
            failed += 1;
        }
    }

    // ── Results ──────────────────────────────────────────────────────
    println!("\n╔══════════════════════════════════════════╗");
    println!("║              Test Results                 ║");
    println!("╠══════════════════════════════════════════╣");
    for (name, pass, detail) in &results {
        let icon = if *pass { "✓" } else { "✗" };
        println!("║ {} {:<25} {}",
            icon,
            name,
            if detail.len() > 12 { &detail[..12] } else { detail }
        );
    }
    println!("╠══════════════════════════════════════════╣");
    println!("║  Passed: {}  Failed: {}                   ║", passed, failed);
    println!("╚══════════════════════════════════════════╝");

    // Always print logs
    harness.print_logs();

    // Clean up
    println!("\n=== Cleaning up ===\n");
    drop(harness);
    println!("  All temp directories removed.");

    if failed > 0 {
        std::process::exit(1);
    }
}

fn print_test_header(name: &str) {
    println!("\n--- {} ---\n", name);
}