use brk_types::{Dollars, Height, Timestamp};
use vecdb::VecIndex;

use crate::{blocks, price};

/// Context shared across block processing.
pub struct ComputeContext {
    /// Starting height for this computation run
    pub starting_height: Height,

    /// Last height to process
    pub last_height: Height,

    /// Pre-computed height -> timestamp mapping
    pub height_to_timestamp: Vec<Timestamp>,

    /// Pre-computed height -> price mapping (if available)
    pub height_to_price: Option<Vec<Dollars>>,
}

impl ComputeContext {
    /// Create a new computation context.
    pub fn new(
        starting_height: Height,
        last_height: Height,
        blocks: &blocks::Vecs,
        price: Option<&price::Vecs>,
    ) -> Self {
        let height_to_timestamp: Vec<Timestamp> =
            blocks.time.height_to_timestamp_fixed.into_iter().collect();

        let height_to_price: Option<Vec<Dollars>> = price
            .map(|p| &p.usd.chainindexes_to_price_close.height)
            .map(|v| v.into_iter().map(|d| *d).collect());

        Self {
            starting_height,
            last_height,
            height_to_timestamp,
            height_to_price,
        }
    }

    /// Get price at height (None if no price data or height out of range).
    pub fn price_at(&self, height: Height) -> Option<Dollars> {
        self.height_to_price
            .as_ref()?
            .get(height.to_usize())
            .copied()
    }

    /// Get timestamp at height.
    pub fn timestamp_at(&self, height: Height) -> Timestamp {
        self.height_to_timestamp[height.to_usize()]
    }
}