use std::time::Duration;

/// Configuration for a Redis Stream consumer.
#[derive(Debug, Clone)]
pub struct StreamConfig {
    /// Redis stream key to consume from (e.g. "notifications:deposits").
    pub stream_key: String,
    /// Redis stream key for dead-letter messages (e.g. "notifications:deposits:dead_letter").
    pub dead_letter_key: String,
    /// Consumer group name (e.g. "notification-service").
    pub consumer_group: String,
    /// Consumer name within the group (e.g. "worker-1").
    pub consumer_name: String,
    /// Number of messages to read per XREADGROUP call.
    pub batch_size: usize,
    /// XREADGROUP block timeout in milliseconds.
    pub block_ms: usize,
    /// Maximum delivery attempts before moving to dead-letter.
    pub max_retries: i64,
    /// Minimum idle time (ms) before a pending message can be reclaimed via XCLAIM.
    pub min_idle_ms: u64,
    /// How often to run the pending message reclaim loop.
    pub reclaim_interval: Duration,
    /// Starting message ID for consumer group creation ("$" = new only, "0" = replay all).
    pub group_start_id: String,
}

impl StreamConfig {
    /// Create a new config with required fields and sensible defaults.
    ///
    /// Defaults: batch_size=10, block_ms=5000, max_retries=5, min_idle_ms=60000,
    /// reclaim_interval=30s, group_start_id="$".
    pub fn new(
        stream_key: impl Into<String>,
        dead_letter_key: impl Into<String>,
        consumer_group: impl Into<String>,
        consumer_name: impl Into<String>,
    ) -> Self {
        Self {
            stream_key: stream_key.into(),
            dead_letter_key: dead_letter_key.into(),
            consumer_group: consumer_group.into(),
            consumer_name: consumer_name.into(),
            batch_size: 10,
            block_ms: 5000,
            max_retries: 5,
            min_idle_ms: 60_000,
            reclaim_interval: Duration::from_secs(30),
            group_start_id: "$".to_string(),
        }
    }

    /// Set minimum idle time for pending message reclaim (milliseconds).
    pub fn with_min_idle_ms(mut self, ms: u64) -> Self {
        self.min_idle_ms = ms;
        self
    }

    /// Set maximum retry count before dead-lettering.
    pub fn with_max_retries(mut self, n: i64) -> Self {
        self.max_retries = n;
        self
    }

    /// Set the group start ID ("$" for new messages only, "0" for replay).
    pub fn with_group_start_id(mut self, id: impl Into<String>) -> Self {
        self.group_start_id = id.into();
        self
    }

    /// Set batch size for XREADGROUP.
    pub fn with_batch_size(mut self, n: usize) -> Self {
        self.batch_size = n;
        self
    }

    /// Set block timeout for XREADGROUP (milliseconds).
    pub fn with_block_ms(mut self, ms: usize) -> Self {
        self.block_ms = ms;
        self
    }

    /// Set reclaim interval.
    pub fn with_reclaim_interval(mut self, interval: Duration) -> Self {
        self.reclaim_interval = interval;
        self
    }
}
