import { metrics, type Tracer, trace } from "@opentelemetry/api";

const meter = metrics.getMeter("@suaveplan/bitpacker-compressed");

export function getBitPackerCompressedTracer(): Tracer {
    return trace.getTracer("@suaveplan/bitpacker-compressed");
}

/**
 * Counter incremented per top-level compress / decompress call. Labels:
 * `op` (`compress` | `decompress`), `algorithm` (e.g. `gzip`, `deflate`,
 * `none`, `rle`), and `success`.
 */
export const compressionOpsTotal = meter.createCounter(
    "bitpacker_compressed.ops.total",
    {
        description: "Total compression / decompression operations",
        unit: "{ops}",
    }
);

/**
 * Histogram of operation duration in milliseconds.
 */
export const compressionOpDurationMs = meter.createHistogram(
    "bitpacker_compressed.op.duration_ms",
    {
        description: "Duration of compression / decompression in milliseconds",
        unit: "ms",
    }
);

/**
 * Histogram of compression ratio (compressed bytes / input bytes), labelled
 * by `algorithm`. Recorded only on successful `compress` calls.
 */
export const compressionRatio = meter.createHistogram(
    "bitpacker_compressed.compression.ratio",
    {
        description:
            "Compression ratio (output_bytes / input_bytes) per successful compress",
        unit: "1",
    }
);

export const BITPACKER_COMPRESSED_SPAN_NAMES = {
    compress: "bitpacker_compressed.compress",
    decompress: "bitpacker_compressed.decompress",
    pack: "bitpacker_compressed.pack",
    unpack: "bitpacker_compressed.unpack",
} as const;