//! Proactive Sync Test Helpers
//!
//! Provides utilities for testing ngit-grasp's proactive sync functionality:
//! - `TestClient` - Client wrapper with built-in retry logic
//! - Event builders for Layer 2 (kind 1621) and Layer 3 (kinds 1, 1111) events
//! - Assertion helpers that return bool (non-panicking)
//!
//! # nostr-sdk 0.43 API Notes
//! - Use field access: `event.id`, `event.tags`, `event.tags.iter()`
//! - Use `Tag::custom(TagKind::custom("name"), vec![...])` syntax
//! - Use `EventBuilder::new(kind, content).tags(tags)` syntax

use std::collections::HashMap;
use std::time::Duration;

use nostr_sdk::prelude::*;

use super::relay::TestRelay;

// NOTE: Using rust-nostr Kind variants:
// - Kind::GitIssue.as_u16() -> Kind::GitIssue (1621)
// - Kind::Comment.as_u16() -> Kind::Comment (1111)
// - Kind::GitRepoAnnouncement.as_u16() -> Kind::GitRepoAnnouncement (30617)

/// Test client with built-in retry logic for connect and send operations.
///
/// Wraps nostr-sdk Client with automatic retry handling suitable for
/// integration tests where connections may take time to establish.
pub struct TestClient {
    client: Client,
    relay_url: String,
    keys: Keys,
}

impl TestClient {
    /// Create a new TestClient and connect to the specified relay.
    ///
    /// Uses retry logic: up to 30 attempts with 100ms delay between each.
    ///
    /// # Arguments
    /// * `relay_url` - WebSocket URL of the relay (e.g., "ws://127.0.0.1:8080")
    /// * `keys` - Nostr keys for signing events
    ///
    /// # Returns
    /// * `Ok(TestClient)` on successful connection
    /// * `Err(String)` if connection fails after all retries
    pub async fn new(relay_url: &str, keys: Keys) -> Result<Self, String> {
        let client = Client::new(keys.clone());

        client
            .add_relay(relay_url)
            .await
            .map_err(|e| format!("Failed to add relay: {}", e))?;

        let test_client = Self {
            client,
            relay_url: relay_url.to_string(),
            keys,
        };

        test_client.connect().await?;

        Ok(test_client)
    }

    /// Connect to the relay with retry logic.
    ///
    /// Attempts connection up to 30 times with 100ms delays (3 seconds total).
    pub async fn connect(&self) -> Result<(), String> {
        self.client.connect().await;

        // Wait for connection with retries (matching existing pattern)
        for attempt in 0..30 {
            tokio::time::sleep(Duration::from_millis(100)).await;
            let relays = self.client.relays().await;
            if relays.values().any(|r| r.is_connected()) {
                return Ok(());
            }
            if attempt == 29 {
                return Err(format!(
                    "Failed to connect to relay {} after 3 seconds",
                    self.relay_url
                ));
            }
        }

        Err("Connection loop exited unexpectedly".to_string())
    }

    /// Send an event with retry logic.
    ///
    /// Attempts to send up to 3 times with exponential backoff:
    /// - Attempt 1: immediate
    /// - Attempt 2: after 200ms
    /// - Attempt 3: after 400ms
    ///
    /// # Arguments
    /// * `event` - The signed event to send
    ///
    /// # Returns
    /// * `Ok(EventId)` on successful send
    /// * `Err(String)` if all attempts fail
    pub async fn send_event(&self, event: &Event) -> Result<EventId, String> {
        let delays = [0, 200, 400]; // Exponential backoff in ms

        for (attempt, delay_ms) in delays.iter().enumerate() {
            if *delay_ms > 0 {
                tokio::time::sleep(Duration::from_millis(*delay_ms)).await;
            }

            match self.client.send_event(event).await {
                Ok(output) => {
                    if !output.success.is_empty() {
                        return Ok(output.val);
                    }
                    // Log failures for debugging
                    if !output.failed.is_empty() {
                        eprintln!(
                            "  Send attempt {} - failures: {:?}",
                            attempt + 1,
                            output.failed
                        );
                        // Try reconnecting if relay disconnected
                        self.client.connect().await;
                    }
                }
                Err(e) => {
                    eprintln!("  Send attempt {} - error: {}", attempt + 1, e);
                }
            }
        }

        Err(format!(
            "Failed to send event {} after 3 attempts",
            event.id
        ))
    }

    /// Get a reference to the keys used by this client.
    pub fn keys(&self) -> &Keys {
        &self.keys
    }

    /// Disconnect from the relay.
    pub async fn disconnect(self) {
        self.client.disconnect().await;
    }
}

// ============================================================================
// Event Builders
// ============================================================================

/// Build a Layer 2 issue event (kind 1618) with a/A/q tags referencing a repository.
///
/// Creates an issue event that references the specified repository coordinate.
/// Supports different tag types for comprehensive Layer 2 filter testing.
///
/// # Arguments
/// * `keys` - Keys for signing the event
/// * `repo_coord` - Repository coordinate (format: "30617:pubkey_hex:identifier")
/// * `title` - Issue title (used as content)
///
/// # Tag Types
/// Uses lowercase 'a' tag by default. For other tag variations, see:
/// - `build_layer2_issue_with_uppercase_a_tag`
/// - `build_layer2_issue_with_q_tag`
///
/// # Returns
/// * `Ok(Event)` - Signed event ready to send
/// * `Err(String)` - If signing fails
pub fn build_layer2_issue_event(
    keys: &Keys,
    repo_coord: &str,
    title: &str,
) -> Result<Event, String> {
    build_layer2_issue_with_tag(keys, repo_coord, title, TagVariant::LowercaseA)
}

/// Build a Layer 2 issue with uppercase 'A' tag.
pub fn build_layer2_issue_with_uppercase_a_tag(
    keys: &Keys,
    repo_coord: &str,
    title: &str,
) -> Result<Event, String> {
    build_layer2_issue_with_tag(keys, repo_coord, title, TagVariant::UppercaseA)
}

/// Build a Layer 2 issue with 'q' (quote) tag.
pub fn build_layer2_issue_with_q_tag(
    keys: &Keys,
    repo_coord: &str,
    title: &str,
) -> Result<Event, String> {
    build_layer2_issue_with_tag(keys, repo_coord, title, TagVariant::QuoteQ)
}

/// Tag variant for Layer 2 events (referencing repo coordinates)
#[derive(Debug, Clone, Copy)]
pub enum TagVariant {
    /// Lowercase 'a' tag - standard addressable reference
    LowercaseA,
    /// Uppercase 'A' tag - some clients use this
    UppercaseA,
    /// Quote 'q' tag - NIP-10 quote reference
    QuoteQ,
}

/// Internal helper to build Layer 2 issue with specified tag variant.
fn build_layer2_issue_with_tag(
    keys: &Keys,
    repo_coord: &str,
    title: &str,
    tag_variant: TagVariant,
) -> Result<Event, String> {
    let tag = match tag_variant {
        TagVariant::LowercaseA => Tag::custom(TagKind::custom("a"), vec![repo_coord.to_string()]),
        TagVariant::UppercaseA => Tag::custom(TagKind::custom("A"), vec![repo_coord.to_string()]),
        TagVariant::QuoteQ => Tag::custom(TagKind::custom("q"), vec![repo_coord.to_string()]),
    };

    let tags = vec![tag];

    EventBuilder::new(Kind::GitIssue, title)
        .tags(tags)
        .sign_with_keys(keys)
        .map_err(|e| format!("Failed to sign Layer 2 issue event: {}", e))
}

/// Build a Layer 3 comment event (kinds 1 or 1111) with e/E/q tags referencing an event ID.
///
/// Creates a comment/reply event that references the specified parent event ID.
/// Supports different kinds and tag types for comprehensive Layer 3 filter testing.
///
/// # Arguments
/// * `keys` - Keys for signing the event
/// * `parent_event_id` - Event ID being referenced (e.g., an issue or patch)
/// * `content` - Comment content
/// * `kind` - Event kind (Kind::TextNote for reply, Kind::Comment for NIP-22 comment)
///
/// # Tag Types
/// - For kind 1111: Uses uppercase 'E' tag (NIP-22 style)
/// - For kind 1: Uses lowercase 'e' tag with "root" marker (NIP-10 style)
///
/// # Returns
/// * `Ok(Event)` - Signed event ready to send
/// * `Err(String)` - If signing fails
pub fn build_layer3_comment_event(
    keys: &Keys,
    parent_event_id: &EventId,
    content: &str,
    kind: Kind,
) -> Result<Event, String> {
    let kind_num = kind.as_u16();

    // Choose tag based on kind (NIP-22 uses E, NIP-10 style uses e)
    let tag = if kind_num == Kind::Comment.as_u16() {
        // NIP-22 comment: uppercase 'E' tag
        Tag::custom(TagKind::custom("E"), vec![parent_event_id.to_hex()])
    } else {
        // Kind 1 reply: lowercase 'e' tag with root marker (NIP-10)
        Tag::custom(
            TagKind::custom("e"),
            vec![parent_event_id.to_hex(), "".to_string(), "root".to_string()],
        )
    };

    let tags = vec![tag];

    EventBuilder::new(kind, content)
        .tags(tags)
        .sign_with_keys(keys)
        .map_err(|e| format!("Failed to sign Layer 3 comment event: {}", e))
}

/// Build a Layer 3 reply (kind 1) with lowercase 'e' tag.
pub fn build_layer3_reply_with_e_tag(
    keys: &Keys,
    parent_event_id: &EventId,
    content: &str,
) -> Result<Event, String> {
    let tag = Tag::custom(
        TagKind::custom("e"),
        vec![parent_event_id.to_hex(), "".to_string(), "root".to_string()],
    );

    EventBuilder::new(Kind::Custom(1), content)
        .tags(vec![tag])
        .sign_with_keys(keys)
        .map_err(|e| format!("Failed to sign Layer 3 reply event: {}", e))
}

/// Build a Layer 3 comment (kind 1111) with uppercase 'E' tag (NIP-22).
pub fn build_layer3_comment_with_uppercase_e_tag(
    keys: &Keys,
    parent_event_id: &EventId,
    content: &str,
) -> Result<Event, String> {
    let tag = Tag::custom(TagKind::custom("E"), vec![parent_event_id.to_hex()]);

    EventBuilder::new(Kind::Comment, content)
        .tags(vec![tag])
        .sign_with_keys(keys)
        .map_err(|e| format!("Failed to sign Layer 3 comment event: {}", e))
}

/// Build a Layer 3 quote (kind 1) with 'q' tag.
pub fn build_layer3_quote_with_q_tag(
    keys: &Keys,
    parent_event_id: &EventId,
    content: &str,
) -> Result<Event, String> {
    let tag = Tag::custom(TagKind::custom("q"), vec![parent_event_id.to_hex()]);

    EventBuilder::new(Kind::Custom(1), content)
        .tags(vec![tag])
        .sign_with_keys(keys)
        .map_err(|e| format!("Failed to sign Layer 3 quote event: {}", e))
}

// ============================================================================
// Repository Announcement Helper
// ============================================================================

/// Create a valid repository announcement event for testing sync.
///
/// This creates a kind 30617 event with required clone and relays tags.
/// The event lists all provided domains so it will be accepted by each
/// relay's write policy.
///
/// # Arguments
/// * `keys` - Keys for signing
/// * `domains` - Slice of domain strings (e.g., "127.0.0.1:8080")
/// * `identifier` - Repository identifier (d-tag)
///
/// # Returns
/// A signed repository announcement event ready to send.
pub fn create_repo_announcement(keys: &Keys, domains: &[&str], identifier: &str) -> Event {
    // Get npub for the clone URL path (format: /<npub>/<identifier>.git)
    let npub = keys
        .public_key()
        .to_bech32()
        .expect("Failed to convert public key to npub");

    // Build clone URLs for all domains (with npub and .git suffix)
    let clone_urls: Vec<String> = domains
        .iter()
        .map(|d| format!("http://{}/{}/{}.git", d, npub, identifier))
        .collect();

    // Build relay URLs for all domains
    let relay_urls: Vec<String> = domains.iter().map(|d| format!("ws://{}", d)).collect();

    // Build tags for repository announcement
    let tags = vec![
        Tag::identifier(identifier),
        Tag::custom(TagKind::custom("clone"), clone_urls),
        Tag::custom(TagKind::custom("relays"), relay_urls),
    ];

    EventBuilder::new(Kind::GitRepoAnnouncement, "Repository state")
        .tags(tags)
        .sign_with_keys(keys)
        .expect("Failed to sign repo announcement")
}

// ============================================================================
// Sync Connection Helpers
// ============================================================================

/// Wait for a sync connection to be established on the syncing relay.
///
/// Polls the relay's metrics endpoint to check for active sync connections.
/// This is more reliable than using fixed sleeps, as it verifies the actual
/// connection state before proceeding with test assertions.
///
/// # Arguments
/// * `syncing_relay_url` - WebSocket URL of the relay that is syncing (e.g., "ws://127.0.0.1:8080")
/// * `expected_connections` - Expected number of sync connections (typically 1 for single bootstrap)
/// * `timeout` - Maximum time to wait for connections to be established
///
/// # Returns
/// * `Ok(())` - Connections established within timeout
/// * `Err(String)` - Timeout waiting for connections, or other error
///
/// # Example
/// ```ignore
/// // After starting relay_b with sync from relay_a
/// let relay_b = TestRelay::start_with_sync(Some(relay_a.url().into())).await;
///
/// // Wait for sync connection to be established
/// wait_for_sync_connection(relay_b.url(), 1, Duration::from_secs(5)).await
///     .expect("Sync connection should be established");
///
/// // Now proceed with test - sync connection is verified
/// ```
pub async fn wait_for_sync_connection(
    syncing_relay_url: &str,
    expected_connections: usize,
    timeout: Duration,
) -> Result<(), String> {
    // Convert ws:// URL to http:// for metrics endpoint
    let http_url = syncing_relay_url
        .replace("ws://", "http://")
        .replace("/", "")
        + "/metrics";

    let start = std::time::Instant::now();
    let poll_interval = Duration::from_millis(100);

    while start.elapsed() < timeout {
        // Fetch metrics
        if let Ok(response) = reqwest::get(&http_url).await {
            if let Ok(metrics) = response.text().await {
                // Look for sync connection metrics
                // The metric name pattern: ngit_sync_connections or similar
                // We check for any indication of established connections
                if check_sync_connections_in_metrics(&metrics, expected_connections) {
                    return Ok(());
                }
            }
        }

        tokio::time::sleep(poll_interval).await;
    }

    Err(format!(
        "Timeout waiting for {} sync connection(s) on {} after {:?}",
        expected_connections, syncing_relay_url, timeout
    ))
}

/// Check metrics string for expected number of sync connections.
///
/// Looks for various metric patterns that indicate sync connections:
/// - ngit_sync_connections (gauge)
/// - ngit_sync_relay_connections (gauge)
/// - Any metric containing "sync" and "connection" with count > 0
fn check_sync_connections_in_metrics(metrics: &str, expected: usize) -> bool {
    // Parse metrics line by line looking for connection counts
    for line in metrics.lines() {
        // Skip comments and empty lines
        if line.starts_with('#') || line.is_empty() {
            continue;
        }

        // Look for sync connection metrics
        // Format: metric_name{labels} value
        // or: metric_name value
        if line.contains("sync") && line.contains("connect") {
            // Extract the value (last space-separated token)
            if let Some(value_str) = line.split_whitespace().last() {
                if let Ok(value) = value_str.parse::<f64>() {
                    if value as usize >= expected {
                        return true;
                    }
                }
            }
        }

        // Also check for specific metric names that might indicate connections
        // ngit_sync_health_state with value 1 or 2 (connecting/healthy)
        if line.contains("ngit_sync_health") {
            if let Some(value_str) = line.split_whitespace().last() {
                if let Ok(value) = value_str.parse::<f64>() {
                    // Health state > 0 typically means connection attempt or established
                    if value > 0.0 && expected > 0 {
                        return true;
                    }
                }
            }
        }
    }

    false
}

// ============================================================================
// Assertion Helpers
// ============================================================================

/// Wait for an event to appear on a relay.
///
/// Polls the relay for the specified event using the provided filter.
/// Returns true if found within timeout, false otherwise.
///
/// **Important:** This function does NOT panic - it returns a bool to allow
/// tests to make their own assertions with descriptive error messages.
///
/// # Arguments
/// * `relay_url` - WebSocket URL of the relay to check
/// * `filter` - Nostr filter to use for querying (should match the expected event)
/// * `timeout` - Maximum time to wait for the event
///
/// # Returns
/// * `true` - Event matching filter was found
/// * `false` - Event not found within timeout, or connection failed
///
/// # Example
/// ```ignore
/// let filter = Filter::new()
///     .kind(Kind::GitPullRequest)
///     .author(keys.public_key())
///     .id(event.id);
///
/// let found = wait_for_event_on_relay(relay.url(), filter, Duration::from_secs(3)).await;
/// assert!(found, "Expected event {} to sync to relay", event.id);
/// ```
pub async fn wait_for_event_on_relay(relay_url: &str, filter: Filter, timeout: Duration) -> bool {
    // Create a temporary client for querying
    let temp_keys = Keys::generate();
    let client = Client::new(temp_keys);

    // Try to connect
    if client.add_relay(relay_url).await.is_err() {
        return false;
    }

    client.connect().await;

    // Wait for connection (brief timeout)
    let mut connected = false;
    for _ in 0..10 {
        tokio::time::sleep(Duration::from_millis(100)).await;
        let relays = client.relays().await;
        if relays.values().any(|r| r.is_connected()) {
            connected = true;
            break;
        }
    }

    if !connected {
        client.disconnect().await;
        return false;
    }

    // Fetch events with the provided timeout
    let result = client.fetch_events(filter, timeout).await;

    client.disconnect().await;

    match result {
        Ok(events) => !events.is_empty(),
        Err(_) => false,
    }
}

/// Build repo coordinate string for use in 'a' tags.
///
/// Format: `30617:pubkey_hex:identifier`
///
/// # Arguments
/// * `keys` - Keys whose public key will be used
/// * `identifier` - Repository identifier (d-tag value)
pub fn repo_coord(keys: &Keys, identifier: &str) -> String {
    format!(
        "{}:{}:{}",
        Kind::GitRepoAnnouncement.as_u16(),
        keys.public_key().to_hex(),
        identifier
    )
}

// ============================================================================
// Metrics Helpers
// ============================================================================

/// Fetch Prometheus metrics from a relay's `/metrics` endpoint.
///
/// Converts the WebSocket URL to HTTP and fetches the metrics endpoint.
/// Useful for verifying sync-related metrics in tests.
///
/// # Arguments
/// * `relay_url` - WebSocket URL of the relay (e.g., "ws://127.0.0.1:8080")
///
/// # Returns
/// * `Ok(String)` - The metrics text in Prometheus format
/// * `Err(reqwest::Error)` - If the request fails
///
/// # Example
/// ```ignore
/// let metrics = fetch_metrics("ws://127.0.0.1:8080").await?;
/// assert!(metrics.contains("ngit_sync_"));
/// ```
pub async fn fetch_metrics(relay_url: &str) -> Result<String, reqwest::Error> {
    // Convert ws:// URL to http:// for metrics endpoint
    let http_url = relay_url.replace("ws://", "http://").replace("/", "") + "/metrics";

    reqwest::get(&http_url).await?.text().await
}

// ============================================================================
// Prometheus Metrics Parser
// ============================================================================

/// A single metric value with its labels
#[derive(Debug, Clone)]
struct MetricValue {
    labels: HashMap<String, String>,
    value: f64,
}

/// Parsed Prometheus metrics with typed accessors.
///
/// Parses Prometheus text format and provides strongly-typed access
/// to metric values with label filtering support.
///
/// # Example
/// ```ignore
/// let metrics = ParsedMetrics::parse(text);
/// let events = metrics.counter("ngit_sync_events_total", &[("source", "live")]);
/// let connected = metrics.relay_connected("ws://127.0.0.1:8080");
/// ```
#[derive(Debug)]
pub struct ParsedMetrics {
    metrics: HashMap<String, Vec<MetricValue>>,
}

impl ParsedMetrics {
    /// Parse Prometheus text format into structured data
    pub fn parse(text: &str) -> Self {
        let mut metrics = HashMap::new();

        for line in text.lines() {
            // Skip comments and empty lines
            if line.starts_with('#') || line.trim().is_empty() {
                continue;
            }

            // Parse metric line: metric_name{label="value"} 123.45
            // Handle both labeled and unlabeled metrics
            if let Some((name_labels, value_str)) = line.rsplit_once(' ') {
                if let Ok(value) = value_str.trim().parse::<f64>() {
                    let (name, labels) = Self::parse_name_and_labels(name_labels);
                    metrics
                        .entry(name.to_string())
                        .or_insert_with(Vec::new)
                        .push(MetricValue { labels, value });
                }
            }
        }

        ParsedMetrics { metrics }
    }

    fn parse_name_and_labels(name_labels: &str) -> (&str, HashMap<String, String>) {
        if let Some(brace_pos) = name_labels.find('{') {
            let name = &name_labels[..brace_pos];
            let labels_str = &name_labels[brace_pos + 1..name_labels.len() - 1];
            let labels = Self::parse_labels(labels_str);
            (name, labels)
        } else {
            (name_labels, HashMap::new())
        }
    }

    fn parse_labels(labels_str: &str) -> HashMap<String, String> {
        let mut labels = HashMap::new();
        for pair in labels_str.split(',') {
            if let Some((key, value)) = pair.split_once('=') {
                let key = key.trim();
                let value = value.trim().trim_matches('"');
                labels.insert(key.to_string(), value.to_string());
            }
        }
        labels
    }

    /// Get counter value with optional label matching
    pub fn counter(&self, name: &str, labels: &[(&str, &str)]) -> Option<u64> {
        self.get_metric(name, labels).map(|v| v as u64)
    }

    /// Get gauge value with optional label matching
    pub fn gauge(&self, name: &str, labels: &[(&str, &str)]) -> Option<i64> {
        self.get_metric(name, labels).map(|v| v as i64)
    }

    fn get_metric(&self, name: &str, labels: &[(&str, &str)]) -> Option<f64> {
        let values = self.metrics.get(name)?;

        if labels.is_empty() {
            // No label filtering - return first match
            values.first().map(|v| v.value)
        } else {
            // Find matching labels
            values
                .iter()
                .find(|v| {
                    labels.iter().all(|(k, expected)| {
                        v.labels
                            .get(*k)
                            .map(|actual| actual == expected)
                            .unwrap_or(false)
                    })
                })
                .map(|v| v.value)
        }
    }

    // Convenience accessors for sync metrics

    /// Get total events synced (no source categorization)
    pub fn events_synced_total(&self) -> Option<u64> {
        self.counter("ngit_sync_events_synced_total", &[])
    }

    /// Check if a specific relay is connected
    pub fn relay_connected(&self, relay: &str) -> Option<bool> {
        self.gauge("ngit_sync_relay_connected", &[("relay", relay)])
            .map(|v| v >= 2) // Syncing (2), Connected (3), or ConnectedHistoricSyncFailures (4)
    }

    /// Get total number of connected relays
    pub fn relays_connected_total(&self) -> Option<i64> {
        self.gauge("ngit_sync_relays_connected_total", &[])
    }

    /// Get total number of tracked relays
    pub fn relays_tracked_total(&self) -> Option<i64> {
        self.gauge("ngit_sync_relays_tracked_total", &[])
    }
}

// ============================================================================
// Metrics Test Harness
// ============================================================================

/// Multi-relay test harness for metrics validation.
///
/// Manages multiple source relays and a syncing relay for testing
/// sync metrics functionality. Uses random ports for all relays
/// to avoid conflicts.
///
/// # Example
/// ```ignore
/// let mut harness = MetricsTestHarness::with_sources(2).await;
/// harness.start_syncing_relay(0).await;  // Sync from source[0]
///
/// let metrics = harness.get_metrics().await?;
/// assert_eq!(metrics.relays_connected_total(), Some(1));
///
/// harness.stop_all().await;
/// ```
pub struct MetricsTestHarness {
    source_relays: Vec<TestRelay>,
    syncing_relay: Option<TestRelay>,
    #[allow(dead_code)]
    nowhere_url: Option<String>,
}

impl MetricsTestHarness {
    /// Start N source relays (uses TestRelay::start with random ports)
    pub async fn with_sources(count: usize) -> Self {
        let mut source_relays = Vec::new();
        for _ in 0..count {
            source_relays.push(TestRelay::start().await);
        }

        Self {
            source_relays,
            syncing_relay: None,
            nowhere_url: None,
        }
    }

    /// Get source relay URL
    pub fn source_url(&self, idx: usize) -> &str {
        self.source_relays[idx].url()
    }

    /// Get source relay domain (for announcement tags)
    pub fn source_domain(&self, idx: usize) -> String {
        self.source_relays[idx].domain()
    }

    /// Submit events to a specific source relay
    pub async fn submit_events(&self, source_idx: usize, events: &[Event]) -> Result<(), String> {
        let relay = &self.source_relays[source_idx];
        let keys = Keys::generate();
        let client = TestClient::new(relay.url(), keys).await?;

        for event in events {
            client.send_event(event).await?;
        }

        client.disconnect().await;
        Ok(())
    }

    /// Start syncing relay pointing to source[idx]
    pub async fn start_syncing_relay(&mut self, source_idx: usize) {
        let source_url = self.source_relays[source_idx].url().to_string();
        self.syncing_relay = Some(TestRelay::start_with_sync(Some(source_url)).await);
    }

    /// Start syncing relay on a specific port pointing to source[idx]
    pub async fn start_syncing_relay_on_port(&mut self, source_idx: usize, port: u16) {
        let source_url = self.source_relays[source_idx].url().to_string();
        self.syncing_relay =
            Some(TestRelay::start_on_port_with_options(port, Some(source_url), false).await);
    }

    /// Start syncing relay pointing to random unused port (for failure tests)
    pub async fn start_syncing_relay_to_nowhere(&mut self) {
        let port = random_unused_port();
        let nowhere_url = format!("ws://127.0.0.1:{}", port);
        self.nowhere_url = Some(nowhere_url.clone());
        self.syncing_relay = Some(TestRelay::start_with_sync(Some(nowhere_url)).await);
    }

    /// Stop a source relay
    pub async fn stop_source(&mut self, source_idx: usize) {
        // We need to take ownership to stop, so we swap with a new relay
        // that we immediately stop. This is a workaround since TestRelay::stop
        // takes self by value.
        let relay = std::mem::replace(
            &mut self.source_relays[source_idx],
            TestRelay::start().await,
        );
        relay.stop().await;
        // Stop the placeholder too
        let placeholder = std::mem::replace(
            &mut self.source_relays[source_idx],
            TestRelay::start().await,
        );
        placeholder.stop().await;
    }

    /// Fetch and parse metrics from syncing relay
    pub async fn get_metrics(&self) -> Result<ParsedMetrics, String> {
        let relay = self
            .syncing_relay
            .as_ref()
            .ok_or_else(|| "Syncing relay not started".to_string())?;

        let metrics_text = fetch_metrics(relay.url())
            .await
            .map_err(|e| format!("Failed to fetch metrics: {}", e))?;

        Ok(ParsedMetrics::parse(&metrics_text))
    }

    /// Get the syncing relay URL (for metrics with relay URL labels)
    pub fn syncing_relay_url(&self) -> Option<&str> {
        self.syncing_relay.as_ref().map(|r| r.url())
    }

    /// Stop all relays
    pub async fn stop_all(mut self) {
        if let Some(relay) = self.syncing_relay.take() {
            relay.stop().await;
        }
        for relay in self.source_relays.drain(..) {
            relay.stop().await;
        }
    }
}

// ============================================================================
// Port Helpers
// ============================================================================

/// Get a random unused port by binding to port 0 and letting the OS assign one
pub fn random_unused_port() -> u16 {
    std::net::TcpListener::bind("127.0.0.1:0")
        .expect("Failed to bind to random port")
        .local_addr()
        .expect("Failed to get local addr")
        .port()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_repo_coord_format() {
        let keys = Keys::generate();
        let coord = repo_coord(&keys, "test-repo");

        assert!(coord.starts_with("30617:"));
        assert!(coord.ends_with(":test-repo"));
        assert_eq!(coord.split(':').count(), 3);
    }

    #[test]
    fn test_build_layer2_issue_event() {
        let keys = Keys::generate();
        let coord = repo_coord(&keys, "my-repo");

        let event =
            build_layer2_issue_event(&keys, &coord, "Test Issue").expect("Should create event");

        // nostr-sdk 0.43: use field access
        assert_eq!(event.kind.as_u16(), Kind::GitIssue.as_u16());

        // Check the tag exists
        let has_a_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "a")
        });
        assert!(has_a_tag, "Event should have 'a' tag");
    }

    #[test]
    fn test_build_layer2_issue_with_uppercase_a() {
        let keys = Keys::generate();
        let coord = repo_coord(&keys, "my-repo");

        let event = build_layer2_issue_with_uppercase_a_tag(&keys, &coord, "Test Issue")
            .expect("Should create event");

        let has_upper_a_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "A")
        });
        assert!(has_upper_a_tag, "Event should have 'A' tag");
    }

    #[test]
    fn test_build_layer2_issue_with_q_tag() {
        let keys = Keys::generate();
        let coord = repo_coord(&keys, "my-repo");

        let event = build_layer2_issue_with_q_tag(&keys, &coord, "Test Issue")
            .expect("Should create event");

        let has_q_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "q")
        });
        assert!(has_q_tag, "Event should have 'q' tag");
    }

    #[test]
    fn test_build_layer3_comment_kind_1111() {
        let keys = Keys::generate();
        let parent_id = EventId::all_zeros();

        let event = build_layer3_comment_event(&keys, &parent_id, "Test comment", Kind::Comment)
            .expect("Should create event");

        assert_eq!(event.kind.as_u16(), Kind::Comment.as_u16());

        // NIP-22 comment should have uppercase 'E' tag
        let has_e_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "E")
        });
        assert!(has_e_tag, "Kind 1111 event should have 'E' tag");
    }

    #[test]
    fn test_build_layer3_comment_kind_1() {
        let keys = Keys::generate();
        let parent_id = EventId::all_zeros();

        let event = build_layer3_comment_event(&keys, &parent_id, "Test reply", Kind::Custom(1))
            .expect("Should create event");

        assert_eq!(event.kind.as_u16(), 1);

        // Kind 1 reply should have lowercase 'e' tag with root marker
        let has_e_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "e")
        });
        assert!(has_e_tag, "Kind 1 event should have 'e' tag");
    }

    #[test]
    fn test_build_layer3_reply_with_e_tag() {
        let keys = Keys::generate();
        let parent_id = EventId::all_zeros();

        let event = build_layer3_reply_with_e_tag(&keys, &parent_id, "Reply content")
            .expect("Should create event");

        assert_eq!(event.kind.as_u16(), 1);

        let has_e_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "e") && slice.get(3).is_some_and(|m| m == "root")
        });
        assert!(has_e_tag, "Should have 'e' tag with root marker");
    }

    #[test]
    fn test_build_layer3_comment_with_uppercase_e() {
        let keys = Keys::generate();
        let parent_id = EventId::all_zeros();

        let event = build_layer3_comment_with_uppercase_e_tag(&keys, &parent_id, "Comment content")
            .expect("Should create event");

        assert_eq!(event.kind.as_u16(), Kind::Comment.as_u16());

        let has_upper_e_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "E")
        });
        assert!(has_upper_e_tag, "Should have uppercase 'E' tag");
    }

    #[test]
    fn test_build_layer3_quote_with_q() {
        let keys = Keys::generate();
        let parent_id = EventId::all_zeros();

        let event = build_layer3_quote_with_q_tag(&keys, &parent_id, "Quote content")
            .expect("Should create event");

        assert_eq!(event.kind.as_u16(), 1);

        let has_q_tag = event.tags.iter().any(|tag| {
            let slice = tag.as_slice();
            slice.first().is_some_and(|t| t == "q")
        });
        assert!(has_q_tag, "Should have 'q' tag");
    }

    // ========================================================================
    // ParsedMetrics Tests
    // ========================================================================

    #[test]
    fn test_parse_counter_with_labels() {
        let text = r#"ngit_sync_events_total{source="live"} 5"#;
        let metrics = ParsedMetrics::parse(text);
        assert_eq!(
            metrics.counter("ngit_sync_events_total", &[("source", "live")]),
            Some(5)
        );
    }

    #[test]
    fn test_parse_gauge_without_labels() {
        let text = r#"ngit_sync_relays_tracked_total 3"#;
        let metrics = ParsedMetrics::parse(text);
        assert_eq!(
            metrics.gauge("ngit_sync_relays_tracked_total", &[]),
            Some(3)
        );
    }

    #[test]
    fn test_parse_empty_metrics() {
        let metrics = ParsedMetrics::parse("");
        assert_eq!(metrics.counter("nonexistent", &[]), None);
    }

    #[test]
    fn test_parse_metric_with_relay_url_label() {
        let text = r#"ngit_sync_relay_connected{relay="ws://127.0.0.1:12345"} 3"#;
        let metrics = ParsedMetrics::parse(text);
        assert_eq!(metrics.relay_connected("ws://127.0.0.1:12345"), Some(true));
    }
}

// ============================================================================
// Unified Sync Test Helper
// ============================================================================

/// Result from running a sync test setup
///
/// Holds all fixtures needed for making assertions in sync tests.
/// Returned by [`run_sync_test`] after setting up the test environment.
pub struct SyncTestResult {
    pub source_relay: TestRelay,
    pub syncing_relay: TestRelay,
    pub maintainer_keys: Keys,
    pub repo_coord: String,
}

/// Helper to send an event to a relay
///
/// Creates a temporary client, sends the event, and disconnects.
async fn send_to_relay(relay: &TestRelay, event: &Event) -> Result<(), String> {
    let temp_keys = Keys::generate();
    let client = TestClient::new(relay.url(), temp_keys).await?;
    client.send_event(event).await?;
    client.disconnect().await;
    Ok(())
}

/// Unified sync test helper that automatically determines sync mode.
///
/// This function sets up a complete sync test environment by determining whether
/// to test historic sync (events sent before syncing relay connects) or live sync
/// (events sent after syncing relay connects) based on which event slice has content.
///
/// # Sync Mode Detection
///
/// - **Historic sync**: If `historic_events` has content and `live_events` is empty
/// - **Live sync**: If `live_events` has content and `historic_events` is empty
/// - **Panics**: If both slices have content or both are empty (invalid usage)
///
/// # Arguments
///
/// * `historic_events` - Events to send BEFORE syncing relay connects (for historic sync tests)
/// * `live_events` - Events to send AFTER syncing relay connects (for live sync tests)
///
/// # Returns
///
/// [`SyncTestResult`] containing test fixtures for assertions
///
/// # Example
///
/// ```ignore
/// // Historic sync test
/// let issue = build_layer2_issue_event(&keys, &repo_coord, "Historic Issue")?;
/// let result = run_sync_test(&[issue], &[]).await;
/// // Assert issue synced to result.syncing_relay
///
/// // Live sync test
/// let comment = build_layer3_comment_event(&keys, &issue.id, "Live Comment", Kind::Comment)?;
/// let result = run_sync_test(&[], &[comment]).await;
/// // Assert comment synced to result.syncing_relay
/// ```
pub async fn run_sync_test(historic_events: &[Event], live_events: &[Event]) -> SyncTestResult {
    // Validate usage - cannot provide events in both slices
    let historic_mode = !historic_events.is_empty();
    let live_mode = !live_events.is_empty();

    if historic_mode && live_mode {
        panic!(
            "Invalid usage: both historic_events and live_events provided. Use one or the other."
        );
    }
    // Note: Both slices can be empty - this tests just the announcement sync

    // 1. Pre-allocate syncing relay port for announcement tags
    let syncing_port = TestRelay::find_free_port();
    let syncing_domain = format!("127.0.0.1:{}", syncing_port);

    // 2. Start source relay
    let source = TestRelay::start().await;

    // 3. Create keys and announcement listing both relays
    let keys = Keys::generate();
    let announcement =
        create_repo_announcement(&keys, &[&source.domain(), &syncing_domain], "test-repo");

    // 4. Send announcement + historic events to source BEFORE syncing relay starts
    send_to_relay(&source, &announcement)
        .await
        .expect("Failed to send announcement");
    for event in historic_events {
        send_to_relay(&source, event)
            .await
            .expect("Failed to send historic event");
    }

    // 5. Start syncing relay (connects to source)
    let syncing =
        TestRelay::start_on_port_with_options(syncing_port, Some(source.url().into()), false).await;

    // 6. Wait for sync connection to establish
    let _ = wait_for_sync_connection(syncing.url(), 1, Duration::from_secs(5)).await;

    // 7. Send live events AFTER connection established
    for event in live_events {
        send_to_relay(&source, event)
            .await
            .expect("Failed to send live event");
    }

    // 8. Allow sync to complete
    tokio::time::sleep(Duration::from_millis(100)).await;

    // 9. Compute repo coordinate before moving keys
    let coordinate = repo_coord(&keys, "test-repo");

    SyncTestResult {
        source_relay: source,
        syncing_relay: syncing,
        maintainer_keys: keys,
        repo_coord: coordinate,
    }
}

// ============================================================================
// Tests for Unified Sync Test Helper
// ============================================================================

#[cfg(test)]
mod sync_helper_tests {
    use super::*;

    // Note: Full integration tests of run_sync_test are in the actual sync test modules.
    // These unit tests only verify the panic conditions for invalid usage.

    #[tokio::test]
    #[should_panic(expected = "both historic_events and live_events provided")]
    async fn test_run_sync_test_panics_with_both_slices() {
        let keys = Keys::generate();
        let coord = repo_coord(&keys, "test");
        let historic =
            build_layer2_issue_event(&keys, &coord, "Historic").expect("Should create event");
        let live = build_layer3_reply_with_e_tag(&keys, &EventId::all_zeros(), "Live")
            .expect("Should create event");

        // Should panic - both slices provided
        let _result = run_sync_test(&[historic], &[live]).await;
    }

    // Note: Empty slices are now allowed - tests just the announcement sync
}