// This file is part of Gear.

// Copyright (C) 2021-2023 Gear Technologies Inc.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

//! Configurations.

use alloc::{collections::BTreeSet, vec::Vec};
use gear_backend_common::lazy_pages::LazyPagesWeights;
use gear_core::{
    costs::{CostPerPage, HostFnWeights},
    pages::{GearPage, WasmPage},
};
use gear_wasm_instrument::syscalls::SysCallName;
use scale_info::scale::{self, Decode, Encode};

/// Number of max pages number to use it in tests.
pub const TESTS_MAX_PAGES_NUMBER: u16 = 512;

/// Contextual block information.
#[derive(Clone, Copy, Debug, Encode, Decode, Default)]
#[codec(crate = scale)]
pub struct BlockInfo {
    /// Height.
    pub height: u32,
    /// Timestamp.
    pub timestamp: u64,
}

/// Memory operations costs.
///
/// Each weight with `lazy_pages_` prefix contains weight for storage read,
/// because for each first page access we need at least check if page exists in storage.
/// But they do not include cost for loading page data from storage into program memory.
/// This weight is taken in account separately, when loading occurs.
///
/// Lazy-pages write accesses does not include cost for uploading page data to storage,
/// because uploading happens after execution, so benchmarks do not include this cost.
/// But they include cost for processing changed page data in runtime.
#[derive(Clone, Debug, Decode, Encode, Default)]
#[codec(crate = scale)]
pub struct PageCosts {
    /// Cost per one [GearPage] signal `read` processing in lazy-pages.
    pub lazy_pages_signal_read: CostPerPage<GearPage>,

    /// Cost per one [GearPage] signal `write` processing in lazy-pages,
    pub lazy_pages_signal_write: CostPerPage<GearPage>,

    /// Cost per one [GearPage] signal `write after read` processing in lazy-pages.
    pub lazy_pages_signal_write_after_read: CostPerPage<GearPage>,

    /// Cost per one [GearPage] host func `read` access processing in lazy-pages.
    pub lazy_pages_host_func_read: CostPerPage<GearPage>,

    /// Cost per one [GearPage] host func `write` access processing in lazy-pages.
    pub lazy_pages_host_func_write: CostPerPage<GearPage>,

    /// Cost per one [GearPage] host func `write after read` access processing in lazy-pages,
    pub lazy_pages_host_func_write_after_read: CostPerPage<GearPage>,

    /// Cost per one [GearPage] data loading from storage and moving it in program memory.
    /// Does not include cost for storage read, because it is taken in account separately.
    pub load_page_data: CostPerPage<GearPage>,

    /// Cost per one [GearPage] uploading data to storage.
    /// Does not include cost for processing changed page data in runtime,
    /// cause it is taken in account separately.
    pub upload_page_data: CostPerPage<GearPage>,

    /// Cost per one [WasmPage] static page. Static pages can have static data,
    /// and executor must to move this data to static pages before execution.
    pub static_page: CostPerPage<WasmPage>,

    /// Cost per one [WasmPage] for memory growing.
    pub mem_grow: CostPerPage<WasmPage>,

    /// Cost per one [GearPage] storage read, when para-chain execution.
    pub parachain_load_heuristic: CostPerPage<GearPage>,
}

impl PageCosts {
    /// Calculates and returns weights for lazy-pages.
    pub fn lazy_pages_weights(&self) -> LazyPagesWeights {
        // Because page may have not data in storage, we do not include
        // cost for loading page data from storage in weights. We provide
        // this cost in `load_page_data` field, so lazy-pages can use it
        // when page data is in storage and must be loaded.
        // On other hand we include cost for uploading page data to storage
        // in each `write` weight, because each write cause page uploading.
        LazyPagesWeights {
            signal_read: self.lazy_pages_signal_read,
            signal_write: self
                .lazy_pages_signal_write
                .saturating_add(self.upload_page_data),
            signal_write_after_read: self
                .lazy_pages_signal_write_after_read
                .saturating_add(self.upload_page_data),
            host_func_read: self.lazy_pages_host_func_read,
            host_func_write: self
                .lazy_pages_host_func_write
                .saturating_add(self.upload_page_data),
            host_func_write_after_read: self
                .lazy_pages_host_func_write_after_read
                .saturating_add(self.upload_page_data),
            load_page_storage_data: self
                .load_page_data
                .saturating_add(self.parachain_load_heuristic),
        }
    }
    /// New one for tests usage.
    pub fn new_for_tests() -> Self {
        let a = 1000.into();
        let b = 4000.into();
        Self {
            lazy_pages_signal_read: a,
            lazy_pages_signal_write: a,
            lazy_pages_signal_write_after_read: a,
            lazy_pages_host_func_read: a,
            lazy_pages_host_func_write: a,
            lazy_pages_host_func_write_after_read: a,
            load_page_data: a,
            upload_page_data: a,
            static_page: b,
            mem_grow: b,
            parachain_load_heuristic: a,
        }
    }
}

/// Execution settings for handling messages.
pub struct ExecutionSettings {
    /// Contextual block information.
    pub block_info: BlockInfo,
    /// Max amount of pages in program memory during execution.
    pub max_pages: WasmPage,
    /// Pages costs.
    pub page_costs: PageCosts,
    /// Minimal amount of existence for account.
    pub existential_deposit: u128,
    /// Weights of host functions.
    pub host_fn_weights: HostFnWeights,
    /// Functions forbidden to be called.
    pub forbidden_funcs: BTreeSet<SysCallName>,
    /// Threshold for inserting into mailbox
    pub mailbox_threshold: u64,
    /// Cost for single block waitlist holding.
    pub waitlist_cost: u64,
    /// Cost of holding a message in dispatch stash.
    pub dispatch_hold_cost: u64,
    /// Reserve for parameter of scheduling.
    pub reserve_for: u32,
    /// Cost for reservation holding.
    pub reservation: u64,
    /// Most recently determined random seed, along with the time in the past since when it was determinable by chain observers.
    // TODO: find a way to put a random seed inside block config.
    pub random_data: (Vec<u8>, u32),
    /// Rent cost per block.
    pub rent_cost: u128,
}

/// Stable parameters for the whole block across processing runs.
#[derive(Clone)]
pub struct BlockConfig {
    /// Block info.
    pub block_info: BlockInfo,
    /// Max allowed page numbers for wasm program.
    pub max_pages: WasmPage,
    /// Allocations config.
    pub page_costs: PageCosts,
    /// Existential deposit.
    pub existential_deposit: u128,
    /// Outgoing limit.
    pub outgoing_limit: u32,
    /// Host function weights.
    pub host_fn_weights: HostFnWeights,
    /// Forbidden functions.
    pub forbidden_funcs: BTreeSet<SysCallName>,
    /// Mailbox threshold.
    pub mailbox_threshold: u64,
    /// Cost for single block waitlist holding.
    pub waitlist_cost: u64,
    /// Cost of holding a message in dispatch stash.
    pub dispatch_hold_cost: u64,
    /// Reserve for parameter of scheduling.
    pub reserve_for: u32,
    /// Cost for reservation holding.
    pub reservation: u64,
    /// One-time db-read cost.
    pub read_cost: u64,
    /// One-time db-write cost.
    pub write_cost: u64,
    /// Per written byte cost.
    pub write_per_byte_cost: u64,
    /// Per loaded byte cost.
    pub read_per_byte_cost: u64,
    /// WASM module instantiation byte cost.
    pub module_instantiation_byte_cost: u64,
    /// Amount of reservations can exist for 1 program.
    pub max_reservations: u64,
    /// WASM code instrumentation base cost.
    pub code_instrumentation_cost: u64,
    /// WASM code instrumentation per-byte cost.
    pub code_instrumentation_byte_cost: u64,
    /// Rent cost per block.
    pub rent_cost: u128,
}