//! Benchmarks of QMDB variants on fixed-size values.
//!
//! While this benchmark involves updating a database with fixed-size values, we also include the db
//! variants capable of handling variable-size values to gauge the impact of the extra indirection
//! they perform.

use commonware_cryptography::{Hasher, Sha256};
use commonware_runtime::{buffer::paged::CacheRef, tokio::Context, BufferPooler, ThreadPooler};
use commonware_storage::{
    qmdb::{
        any::{
            ordered::{fixed::Db as OFixed, variable::Db as OVariable},
            traits::{DbAny, MerkleizedBatch as _, UnmerkleizedBatch as _},
            unordered::{fixed::Db as UFixed, variable::Db as UVariable},
            FixedConfig as AConfig, VariableConfig as VariableAnyConfig,
        },
        current::{
            ordered::{fixed::Db as OCurrent, variable::Db as OVCurrent},
            unordered::{fixed::Db as UCurrent, variable::Db as UVCurrent},
            FixedConfig as CConfig, VariableConfig as VariableCurrentConfig,
        },
        store::LogStore,
    },
    translator::EightCap,
};
use commonware_utils::{NZUsize, NZU16, NZU64};
use rand::{rngs::StdRng, RngCore, SeedableRng};
use std::num::{NonZeroU16, NonZeroU64, NonZeroUsize};

pub mod generate;
pub mod init;

pub type Digest = <Sha256 as Hasher>::Digest;

#[derive(Debug, Clone, Copy)]
enum Variant {
    AnyUnorderedFixed,
    AnyOrderedFixed,
    AnyUnorderedVariable,
    AnyOrderedVariable,
    CurrentUnorderedFixed,
    CurrentOrderedFixed,
    CurrentUnorderedVariable,
    CurrentOrderedVariable,
}

impl Variant {
    pub const fn name(&self) -> &'static str {
        match self {
            Self::AnyUnorderedFixed => "any::unordered::fixed",
            Self::AnyOrderedFixed => "any::ordered::fixed",
            Self::AnyUnorderedVariable => "any::unordered::variable",
            Self::AnyOrderedVariable => "any::ordered::variable",
            Self::CurrentUnorderedFixed => "current::unordered::fixed",
            Self::CurrentOrderedFixed => "current::ordered::fixed",
            Self::CurrentUnorderedVariable => "current::unordered::variable",
            Self::CurrentOrderedVariable => "current::ordered::variable",
        }
    }
}

const VARIANTS: [Variant; 8] = [
    Variant::AnyUnorderedFixed,
    Variant::AnyOrderedFixed,
    Variant::AnyUnorderedVariable,
    Variant::AnyOrderedVariable,
    Variant::CurrentUnorderedFixed,
    Variant::CurrentOrderedFixed,
    Variant::CurrentUnorderedVariable,
    Variant::CurrentOrderedVariable,
];

const ITEMS_PER_BLOB: NonZeroU64 = NZU64!(50_000);
const PARTITION_SUFFIX: &str = "any-fixed-bench-partition";

/// Chunk size for the current QMDB bitmap - must be a power of 2 (as assumed in
/// current::grafting_height()) and a multiple of digest size.
const CHUNK_SIZE: usize = 32;

/// Threads (cores) to use for parallelization. We pick 8 since our benchmarking pipeline is
/// configured to provide 8 cores.
const THREADS: NonZeroUsize = NZUsize!(8);

/// Use a "prod sized" page size to test the performance of the journal.
const PAGE_SIZE: NonZeroU16 = NZU16!(16384);

/// The number of pages to cache in the page cache.
const PAGE_CACHE_SIZE: NonZeroUsize = NZUsize!(10_000);

/// Default delete frequency (1/10th of the updates will be deletes).
const DELETE_FREQUENCY: u32 = 10;

/// Default write buffer size.
const WRITE_BUFFER_SIZE: NonZeroUsize = NZUsize!(1024);

/// Db type aliases for Any databases.
type UFixedDb = UFixed<Context, Digest, Digest, Sha256, EightCap>;
type OFixedDb = OFixed<Context, Digest, Digest, Sha256, EightCap>;
type UVAnyDb = UVariable<Context, Digest, Digest, Sha256, EightCap>;
type OVAnyDb = OVariable<Context, Digest, Digest, Sha256, EightCap>;

type UCurrentDb = UCurrent<Context, Digest, Digest, Sha256, EightCap, CHUNK_SIZE>;
type OCurrentDb = OCurrent<Context, Digest, Digest, Sha256, EightCap, CHUNK_SIZE>;
type UVCurrentDb = UVCurrent<Context, Digest, Digest, Sha256, EightCap, CHUNK_SIZE>;
type OVCurrentDb = OVCurrent<Context, Digest, Digest, Sha256, EightCap, CHUNK_SIZE>;

/// Configuration for any QMDB.
fn any_cfg(context: &(impl BufferPooler + ThreadPooler)) -> AConfig<EightCap> {
    AConfig::<EightCap> {
        mmr_journal_partition: format!("journal-{PARTITION_SUFFIX}"),
        mmr_metadata_partition: format!("metadata-{PARTITION_SUFFIX}"),
        mmr_items_per_blob: ITEMS_PER_BLOB,
        mmr_write_buffer: WRITE_BUFFER_SIZE,
        log_journal_partition: format!("log-journal-{PARTITION_SUFFIX}"),
        log_items_per_blob: ITEMS_PER_BLOB,
        log_write_buffer: WRITE_BUFFER_SIZE,
        translator: EightCap,
        thread_pool: Some(context.create_thread_pool(THREADS).unwrap()),
        page_cache: CacheRef::from_pooler(context, PAGE_SIZE, PAGE_CACHE_SIZE),
    }
}

/// Configuration for current QMDB.
fn current_cfg(context: &(impl BufferPooler + ThreadPooler)) -> CConfig<EightCap> {
    CConfig::<EightCap> {
        mmr_journal_partition: format!("journal-{PARTITION_SUFFIX}"),
        mmr_metadata_partition: format!("metadata-{PARTITION_SUFFIX}"),
        mmr_items_per_blob: ITEMS_PER_BLOB,
        mmr_write_buffer: WRITE_BUFFER_SIZE,
        log_journal_partition: format!("log-journal-{PARTITION_SUFFIX}"),
        log_items_per_blob: ITEMS_PER_BLOB,
        log_write_buffer: WRITE_BUFFER_SIZE,
        grafted_mmr_metadata_partition: format!("grafted-mmr-metadata-{PARTITION_SUFFIX}"),
        translator: EightCap,
        thread_pool: Some(context.create_thread_pool(THREADS).unwrap()),
        page_cache: CacheRef::from_pooler(context, PAGE_SIZE, PAGE_CACHE_SIZE),
    }
}

fn variable_any_cfg(
    context: &(impl BufferPooler + ThreadPooler),
) -> VariableAnyConfig<EightCap, ((), ())> {
    VariableAnyConfig::<EightCap, ((), ())> {
        mmr_journal_partition: format!("journal-{PARTITION_SUFFIX}"),
        mmr_metadata_partition: format!("metadata-{PARTITION_SUFFIX}"),
        mmr_items_per_blob: ITEMS_PER_BLOB,
        mmr_write_buffer: WRITE_BUFFER_SIZE,
        log_partition: format!("log-journal-{PARTITION_SUFFIX}"),
        log_codec_config: ((), ()),
        log_items_per_blob: ITEMS_PER_BLOB,
        log_write_buffer: WRITE_BUFFER_SIZE,
        log_compression: None,
        translator: EightCap,
        thread_pool: Some(context.create_thread_pool(THREADS).unwrap()),
        page_cache: CacheRef::from_pooler(context, PAGE_SIZE, PAGE_CACHE_SIZE),
    }
}

/// Configuration for variable current QMDB.
fn variable_current_cfg(
    context: &(impl BufferPooler + ThreadPooler),
) -> VariableCurrentConfig<EightCap, ((), ())> {
    VariableCurrentConfig::<EightCap, ((), ())> {
        mmr_journal_partition: format!("journal-{PARTITION_SUFFIX}"),
        mmr_metadata_partition: format!("metadata-{PARTITION_SUFFIX}"),
        mmr_items_per_blob: ITEMS_PER_BLOB,
        mmr_write_buffer: WRITE_BUFFER_SIZE,
        log_partition: format!("log-journal-{PARTITION_SUFFIX}"),
        log_codec_config: ((), ()),
        log_items_per_blob: ITEMS_PER_BLOB,
        log_write_buffer: WRITE_BUFFER_SIZE,
        log_compression: None,
        grafted_mmr_metadata_partition: format!("grafted-mmr-metadata-{PARTITION_SUFFIX}"),
        translator: EightCap,
        thread_pool: Some(context.create_thread_pool(THREADS).unwrap()),
        page_cache: CacheRef::from_pooler(context, PAGE_SIZE, PAGE_CACHE_SIZE),
    }
}

/// Get an unordered fixed Any QMDB instance instance.
async fn get_any_unordered_fixed(ctx: Context) -> UFixedDb {
    let any_cfg = any_cfg(&ctx);
    UFixedDb::init(ctx, any_cfg).await.unwrap()
}

/// Get an ordered fixed Any QMDB instance instance.
async fn get_any_ordered_fixed(ctx: Context) -> OFixedDb {
    let any_cfg = any_cfg(&ctx);
    OFixedDb::init(ctx, any_cfg).await.unwrap()
}

/// Get an unordered variable Any QMDB instance instance.
async fn get_any_unordered_variable(ctx: Context) -> UVAnyDb {
    let variable_any_cfg = variable_any_cfg(&ctx);
    UVAnyDb::init(ctx, variable_any_cfg).await.unwrap()
}

/// Get an ordered variable Any QMDB instance instance.
async fn get_any_ordered_variable(ctx: Context) -> OVAnyDb {
    let variable_any_cfg = variable_any_cfg(&ctx);
    OVAnyDb::init(ctx, variable_any_cfg).await.unwrap()
}

/// Get an unordered current QMDB instance.
async fn get_current_unordered_fixed(ctx: Context) -> UCurrentDb {
    let current_cfg = current_cfg(&ctx);
    UCurrent::<_, _, _, Sha256, EightCap, CHUNK_SIZE>::init(ctx, current_cfg)
        .await
        .unwrap()
}

/// Get an ordered current QMDB instance.
async fn get_current_ordered_fixed(ctx: Context) -> OCurrentDb {
    let current_cfg = current_cfg(&ctx);
    OCurrent::<_, _, _, Sha256, EightCap, CHUNK_SIZE>::init(ctx, current_cfg)
        .await
        .unwrap()
}

/// Get an unordered variable current QMDB instance.
async fn get_current_unordered_variable(ctx: Context) -> UVCurrentDb {
    let variable_current_cfg = variable_current_cfg(&ctx);
    UVCurrent::<_, _, _, Sha256, EightCap, CHUNK_SIZE>::init(ctx, variable_current_cfg)
        .await
        .unwrap()
}

/// Get an ordered variable current QMDB instance.
async fn get_current_ordered_variable(ctx: Context) -> OVCurrentDb {
    let variable_current_cfg = variable_current_cfg(&ctx);
    OVCurrent::<_, _, _, Sha256, EightCap, CHUNK_SIZE>::init(ctx, variable_current_cfg)
        .await
        .unwrap()
}

/// Generate a large db with random data. The function seeds the db with exactly `num_elements`
/// elements by inserting them in order, each with a new random value. Then, it performs
/// `num_operations` over these elements, each selected uniformly at random for each operation. The
/// ratio of updates to deletes is configured with `DELETE_FREQUENCY`. The database is committed
/// after every `commit_frequency` operations (if Some), or at the end (if None).
async fn gen_random_kv<M>(
    db: &mut M,
    num_elements: u64,
    num_operations: u64,
    commit_frequency: Option<u32>,
) where
    M: DbAny<Key = Digest> + LogStore<Value = Digest>,
{
    let mut rng = StdRng::seed_from_u64(42);

    // Seed the db with `num_elements` entries.
    {
        let mut batch = db.new_batch();
        for i in 0u64..num_elements {
            let k = Sha256::hash(&i.to_be_bytes());
            let v = Sha256::hash(&rng.next_u32().to_be_bytes());
            batch.write(k, Some(v));
        }
        let finalized = batch.merkleize(None).await.unwrap().finalize();
        db.apply_batch(finalized).await.unwrap();
    }

    // Perform `num_operations` random updates/deletes, committing periodically.
    {
        let mut batch = db.new_batch();
        for _ in 0u64..num_operations {
            let rand_key = Sha256::hash(&(rng.next_u64() % num_elements).to_be_bytes());
            if rng.next_u32() % DELETE_FREQUENCY == 0 {
                batch.write(rand_key, None);
                continue;
            }
            let v = Sha256::hash(&rng.next_u32().to_be_bytes());
            batch.write(rand_key, Some(v));
            if let Some(freq) = commit_frequency {
                if rng.next_u32() % freq == 0 {
                    let finalized = batch.merkleize(None).await.unwrap().finalize();
                    db.apply_batch(finalized).await.unwrap();
                    batch = db.new_batch();
                }
            }
        }
        let finalized = batch.merkleize(None).await.unwrap().finalize();
        db.apply_batch(finalized).await.unwrap();
    }
}