steel_core/player/game_mode/

block_breaking.rs

//! Block breaking state machine for players.
//!
//! This module implements the logic from Java's `ServerPlayerGameMode` for handling
//! block breaking, including progress tracking and validation.

use std::sync::Arc;

use steel_protocol::packets::game::CBlockUpdate;
use steel_registry::blocks::block_state_ext::BlockStateExt;
use steel_registry::data_components::AdventureModePredicate;
use steel_registry::data_components::vanilla_components::{CAN_BREAK, CAN_PLACE_ON};
use steel_registry::equipment::EquipmentSlot;
use steel_registry::stat::vanilla_stat_types;
use steel_registry::vanilla_attributes;
use steel_registry::{
    REGISTRY, blocks::properties::Direction, item_stack::ItemStack, vanilla_blocks,
    vanilla_game_events,
};
use steel_utils::{
    BlockPos, BlockStateId,
    nbt::compare_nbt_compounds,
    types::{GameType, InteractionHand, UpdateFlags},
};

use crate::behavior::{BLOCK_BEHAVIORS, BlockLootContext};
use crate::block_entity::BlockEntity;
use crate::entity::{Entity, LivingEntity};
use crate::fluid::fluid_state_to_block;
use crate::player::Player;
use crate::player::food_data::food_constants;
use crate::world::{ConditionalBlockSetResult, World, game_event::GameEventContext};

impl Player {
    /// Mirrors vanilla `Player.mayUseItemAt` for adventure-mode item use.
    pub(crate) fn may_use_item_at(
        &self,
        pos: BlockPos,
        direction: Direction,
        item_stack: &ItemStack,
    ) -> bool {
        if self.abilities.lock().may_build {
            return true;
        }

        let Some(can_place_on) = item_stack.get(CAN_PLACE_ON) else {
            return false;
        };
        let target = pos.relative(direction.opposite());
        let world = self.get_world();
        Self::matches_adventure_mode_predicate(can_place_on, &world, target)
    }

    /// Mirrors vanilla `Player.blockActionRestricted` for block breaking.
    pub(super) fn block_action_restricted(&self, world: &World, pos: BlockPos) -> bool {
        let game_mode = self.game_mode();
        if !matches!(game_mode, GameType::Adventure | GameType::Spectator) {
            return false;
        }
        if game_mode == GameType::Spectator {
            return true;
        }
        if self.abilities.lock().may_build {
            return false;
        }

        // TODO: Retain Vanilla's mutable per-component AdventureModePredicate
        // cache once Steel's item components support that identity. Until then,
        // snapshotting safely releases the inventory lock but reevaluates each use.
        let can_break = {
            let inventory = self.inventory.lock();
            let item = inventory.get_selected_item();
            if item.is_empty() {
                return true;
            }
            item.get(CAN_BREAK).cloned()
        };
        let Some(can_break) = can_break else {
            return true;
        };
        !Self::matches_adventure_mode_predicate(&can_break, world, pos)
    }

    fn matches_adventure_mode_predicate(
        predicate: &AdventureModePredicate,
        world: &World,
        pos: BlockPos,
    ) -> bool {
        let state = world.get_block_state(pos);
        // Vanilla's BlockInWorld overload intentionally does not test the
        // predicate's block-entity component matchers.
        predicate.predicates().iter().any(|predicate| {
            if !predicate.matches_state(state) {
                return false;
            }
            let Some(expected_nbt) = predicate.nbt() else {
                return true;
            };
            let Some(block_entity) = world.get_block_entity(pos) else {
                return false;
            };
            let actual_nbt = block_entity.save_with_full_metadata();
            compare_nbt_compounds(expected_nbt.tag(), &actual_nbt, true)
        })
    }
}

/// Manages the block breaking state for a player.
///
/// Based on Java's `ServerPlayerGameMode` fields and logic.
pub struct BlockBreakingManager {
    /// Whether the player is currently breaking a block.
    is_destroying_block: bool,
    /// The tick when destruction started.
    destroy_progress_start: u64,
    /// The position of the block being destroyed.
    destroy_pos: BlockPos,
    /// The current game tick counter.
    game_ticks: u64,
    /// Whether there's a delayed destroy pending (for slow mining).
    has_delayed_destroy: bool,
    /// Position of the delayed destroy.
    delayed_destroy_pos: BlockPos,
    /// The tick when delayed destroy started.
    delayed_tick_start: u64,
    /// The last sent destruction progress state (0-9, or -1 for none).
    last_sent_state: i32,
}

impl Default for BlockBreakingManager {
    fn default() -> Self {
        Self::new()
    }
}

impl BlockBreakingManager {
    /// Creates a new block breaking manager.
    #[must_use]
    pub const fn new() -> Self {
        Self {
            is_destroying_block: false,
            destroy_progress_start: 0,
            destroy_pos: BlockPos::new(0, 0, 0),
            game_ticks: 0,
            has_delayed_destroy: false,
            delayed_destroy_pos: BlockPos::new(0, 0, 0),
            delayed_tick_start: 0,
            last_sent_state: -1,
        }
    }

    /// Ticks the block breaking manager.
    ///
    /// This handles delayed destruction and updates break progress.
    pub fn tick(&mut self, player: &Player, world: &Arc<World>) {
        self.game_ticks += 1;

        if self.has_delayed_destroy {
            let state = world.get_block_state(self.delayed_destroy_pos);
            if is_air(state) {
                self.has_delayed_destroy = false;
            } else {
                let progress = self.increment_destroy_progress(
                    player,
                    world,
                    state,
                    self.delayed_destroy_pos,
                    self.delayed_tick_start,
                );
                if progress >= 1.0 {
                    self.has_delayed_destroy = false;
                    self.destroy_block(player, world, self.delayed_destroy_pos);
                }
            }
        } else if self.is_destroying_block {
            let state = world.get_block_state(self.destroy_pos);
            if is_air(state) {
                // Block was broken by something else
                world.broadcast_block_destruction(player.id(), self.destroy_pos, -1);
                self.last_sent_state = -1;
                self.is_destroying_block = false;
            } else {
                self.increment_destroy_progress(
                    player,
                    world,
                    state,
                    self.destroy_pos,
                    self.destroy_progress_start,
                );
            }
        }
    }

    /// Calculates and updates destruction progress, broadcasting to clients.
    fn increment_destroy_progress(
        &mut self,
        player: &Player,
        world: &Arc<World>,
        block_state: BlockStateId,
        pos: BlockPos,
        destroy_start_tick: u64,
    ) -> f32 {
        let ticks_spent = self.game_ticks.saturating_sub(destroy_start_tick);
        let destroy_speed = get_destroy_progress(player, block_state);
        let progress = destroy_speed * (ticks_spent + 1) as f32;
        let state = (progress * 10.0) as i32;

        if state != self.last_sent_state {
            world.broadcast_block_destruction(player.id(), pos, state);
            self.last_sent_state = state;
        }

        progress
    }

    /// Handles a block break action from the client.
    ///
    /// Note: The caller (packet handler) is responsible for calling `ack_block_changes_up_to`
    /// after this method returns, matching vanilla behavior.
    pub fn handle_block_break_action(
        &mut self,
        player: &Player,
        world: &Arc<World>,
        pos: BlockPos,
        action: BlockBreakAction,
        _direction: Direction,
    ) {
        // Validate interaction range
        if !player.is_within_block_interaction_range(pos) {
            return;
        }

        // Validate Y coordinate
        if pos.y() >= world.max_build_height() {
            player.send_packet(CBlockUpdate {
                pos,
                block_state: world.get_block_state(pos),
            });
            return;
        }

        match action {
            BlockBreakAction::Start => {
                // Check may_interact permission
                if !world.may_interact(player, pos) {
                    player.send_packet(CBlockUpdate {
                        pos,
                        block_state: world.get_block_state(pos),
                    });
                    return;
                }

                // Creative mode: instant break
                if player.game_mode() == GameType::Creative {
                    self.destroy_and_ack(player, world, pos);
                    return;
                }

                if player.block_action_restricted(world, pos) {
                    player.send_packet(CBlockUpdate {
                        pos,
                        block_state: world.get_block_state(pos),
                    });
                    return;
                }

                self.destroy_progress_start = self.game_ticks;
                let block_state = world.get_block_state(pos);

                if !is_air(block_state) {
                    // TODO: Call EnchantmentHelper.onHitBlock before blockState.attack.
                    BLOCK_BEHAVIORS
                        .get_behavior(block_state.get_block())
                        .attack(block_state, world, pos, player);

                    let progress = get_destroy_progress(player, block_state);

                    if progress >= 1.0 {
                        // Insta-mine
                        self.destroy_and_ack(player, world, pos);
                    } else {
                        // Start breaking
                        if self.is_destroying_block {
                            // Send block update for the old position to cancel client prediction
                            player.send_packet(CBlockUpdate {
                                pos: self.destroy_pos,
                                block_state: world.get_block_state(self.destroy_pos),
                            });
                        }

                        self.is_destroying_block = true;
                        self.destroy_pos = pos;
                        let state = (progress * 10.0) as i32;
                        world.broadcast_block_destruction(player.id(), pos, state);
                        self.last_sent_state = state;
                    }
                }
            }

            BlockBreakAction::Stop => {
                if pos == self.destroy_pos {
                    let ticks_spent = self.game_ticks.saturating_sub(self.destroy_progress_start);
                    let block_state = world.get_block_state(pos);

                    if !is_air(block_state) {
                        let destroy_speed = get_destroy_progress(player, block_state);
                        let progress = destroy_speed * (ticks_spent + 1) as f32;

                        if progress >= 0.7 {
                            // Complete the break
                            self.is_destroying_block = false;
                            world.broadcast_block_destruction(player.id(), pos, -1);
                            self.destroy_and_ack(player, world, pos);
                            return;
                        }

                        if !self.has_delayed_destroy {
                            // Set up delayed destroy
                            self.is_destroying_block = false;
                            self.has_delayed_destroy = true;
                            self.delayed_destroy_pos = pos;
                            self.delayed_tick_start = self.destroy_progress_start;
                        }
                    }
                }
            }

            BlockBreakAction::Abort => {
                self.is_destroying_block = false;

                if self.destroy_pos != pos {
                    log::warn!(
                        "Mismatch in destroy block pos: {:?} vs {:?}",
                        self.destroy_pos,
                        pos
                    );
                    world.broadcast_block_destruction(player.id(), self.destroy_pos, -1);
                }

                world.broadcast_block_destruction(player.id(), pos, -1);
            }
        }
    }

    /// Destroys a block and sends appropriate response.
    fn destroy_and_ack(&mut self, player: &Player, world: &Arc<World>, pos: BlockPos) {
        if !self.destroy_block(player, world, pos) {
            // Send block update to resync client
            player.send_packet(CBlockUpdate {
                pos,
                block_state: world.get_block_state(pos),
            });
        }
    }

    /// Destroys a block at the given position.
    ///
    /// Returns true if the block was successfully destroyed.
    #[expect(
        clippy::unused_self,
        reason = "method belongs logically to BlockBreakingManager and will use self when additional state is added"
    )]
    fn destroy_block(&self, player: &Player, world: &Arc<World>, pos: BlockPos) -> bool {
        let state = world.get_block_state(pos);

        if player.get_abilities().instabuild && !held_item_can_destroy_in_creative(player) {
            return false;
        }

        // Check if player's tool can destroy this block
        // TODO: Implement canDestroyBlock check for adventure mode

        // Get block info
        let Some(_block) = REGISTRY.blocks.by_state_id(state) else {
            return false;
        };

        // TODO: Check for GameMasterBlock (command blocks, etc.)
        // TODO: Check blockActionRestricted

        let behavior = BLOCK_BEHAVIORS.get_behavior(state.get_block());
        let adjusted_state = behavior.player_will_destroy(state, world, pos, player);
        world.game_event(
            &vanilla_game_events::BLOCK_DESTROY,
            pos,
            &GameEventContext::new(Some(player), Some(adjusted_state)),
        );
        let state_after_player_will_destroy = world.get_block_state(pos);

        // Vanilla parity: fluidState.createLegacyBlock() — breaking a waterlogged
        // block leaves water behind instead of air.
        let replacement = fluid_state_to_block(state.get_fluid_state());

        // Read before the removal below, so loot generation still sees the
        // block entity's contents.
        let block_entity = world.get_block_entity(pos);

        // Vanilla removes the live state after `playerWillDestroy`; tripwire uses
        // that callback to set DISARMED before the same block is removed.
        let removed_by_player_break = !state_after_player_will_destroy.is_air()
            && world.set_block_if_unchanged(
                pos,
                state_after_player_will_destroy,
                replacement,
                UpdateFlags::UPDATE_ALL,
            ) == ConditionalBlockSetResult::Changed;
        let changed_by_player_will_destroy = state_after_player_will_destroy != state;
        let changed = changed_by_player_will_destroy || removed_by_player_break;

        if removed_by_player_break {
            behavior.destroy(adjusted_state, world, pos);

            // Play block destruction particles and sound (skip for fire blocks like vanilla)
            // Exclude the breaking player as they see the effect client-side
            let block = REGISTRY.blocks.by_state_id(adjusted_state);
            let is_fire = block.is_some_and(|b| {
                b.key == vanilla_blocks::FIRE.key || b.key == vanilla_blocks::SOUL_FIRE.key
            });
            if !is_fire {
                world.destroy_block_effect(pos, u32::from(adjusted_state.0), Some(player.id()));
            }

            // Vanilla snapshots the tool before Item.mineBlock can damage or
            // consume it, then uses that snapshot for loot and post-break effects.
            let (has_correct_tool, destroyed_with) = {
                let inv = player.inventory.lock();
                let main_hand = inv.get_item_in_hand(InteractionHand::MainHand);
                (
                    main_hand.is_correct_tool_for_drops(adjusted_state)
                        || !requires_correct_tool(adjusted_state),
                    main_hand.copy_with_count(main_hand.count),
                )
            };

            // Damage the tool if the block has non-zero destroy time
            // This is done before playerDestroy, matching vanilla's Item.mineBlock
            let block_destroy_time = REGISTRY
                .blocks
                .by_state_id(adjusted_state)
                .map_or(0.0, |b| b.config.destroy_time);

            if block_destroy_time != 0.0 {
                let broke = {
                    let mut inv = player.inventory.lock();
                    let damage_per_block = inv.get_selected_item().get_tool_damage_per_block();

                    if damage_per_block > 0 {
                        // Use with_selected_item_mut to ensure set_changed() is called
                        // Skip damage if player has infinite materials (creative mode)
                        let has_infinite_materials = player.has_infinite_materials();
                        inv.with_selected_item_mut(|main_hand| {
                            let item = main_hand.item;
                            main_hand
                                .hurt_and_break(damage_per_block, has_infinite_materials)
                                .then_some(item)
                        })
                    } else {
                        None
                    }
                };

                if let Some(item) = broke {
                    player.on_equipped_item_broken(item, EquipmentSlot::MainHand);
                    log::debug!("Tool broke while mining block at {pos:?}");
                }
            }

            // Handle drops (skip for creative/spectator)
            let game_mode = player.game_mode();
            if game_mode != GameType::Spectator
                && game_mode != GameType::Creative
                && has_correct_tool
            {
                player.award_stat(&vanilla_stat_types::BLOCK_MINED, state.get_block());
                player.cause_food_exhaustion(food_constants::EXHAUSTION_MINE);

                drop_block_loot(
                    player,
                    world,
                    pos,
                    adjusted_state,
                    &destroyed_with,
                    block_entity.as_deref(),
                );
                behavior.player_destroy(
                    world,
                    player,
                    pos,
                    adjusted_state,
                    block_entity.as_ref(),
                    &destroyed_with,
                );
            }
        }

        changed
    }
}

/// Block break action types.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum BlockBreakAction {
    /// Player started breaking a block.
    Start,
    /// Player stopped breaking a block (finished or released).
    Stop,
    /// Player aborted breaking a block.
    Abort,
}

fn held_item_can_destroy_in_creative(player: &Player) -> bool {
    let inventory = player.inventory.lock();
    let main_hand = inventory.get_item_in_hand(InteractionHand::MainHand);
    main_hand.can_destroy_blocks_in_creative()
}

/// Checks if a block state is air.
fn is_air(state: BlockStateId) -> bool {
    let Some(block) = REGISTRY.blocks.by_state_id(state) else {
        return true;
    };
    block.config.is_air
}

/// Checks if a block requires the correct tool for drops.
fn requires_correct_tool(state: BlockStateId) -> bool {
    let Some(block) = REGISTRY.blocks.by_state_id(state) else {
        return false;
    };
    block.config.requires_correct_tool_for_drops
}

/// Gets the destroy progress per tick for a block.
///
/// This is based on the vanilla formula:
/// `1.0 / (destroy_time * 30.0)` for survival with correct tool
/// `1.0 / (destroy_time * 100.0)` for survival with wrong tool
/// Instant break for creative mode.
fn get_destroy_progress(player: &Player, block_state: BlockStateId) -> f32 {
    let Some(block) = REGISTRY.blocks.by_state_id(block_state) else {
        return 0.0;
    };

    let destroy_time = block.config.destroy_time;

    // Instant break for creative
    if player.game_mode() == GameType::Creative {
        return 1.0;
    }

    // Unbreakable block
    if destroy_time < 0.0 {
        return 0.0;
    }

    // Instant break for destroy_time == 0
    if destroy_time == 0.0 {
        return 1.0;
    }

    // Get player's mining speed
    let mining_speed = {
        let inv = player.inventory.lock();
        let main_hand = inv.get_item_in_hand(InteractionHand::MainHand);
        main_hand.get_destroy_speed(block_state)
    };

    // Check if player has the correct tool
    let has_correct_tool = {
        let inv = player.inventory.lock();
        let main_hand = inv.get_item_in_hand(InteractionHand::MainHand);
        main_hand.is_correct_tool_for_drops(block_state)
    };

    // Apply speed modifiers
    let speed = mining_speed;

    // TODO: Apply efficiency enchantment
    // TODO: Apply haste/mining fatigue effects
    // TODO: Apply underwater/in-air penalties

    // Calculate destroy progress per tick
    // Vanilla formula: speed / hardness / (hasCorrectTool ? 30 : 100)
    let divisor = if has_correct_tool || !block.config.requires_correct_tool_for_drops {
        30.0
    } else {
        100.0
    };

    speed / destroy_time / divisor
}

/// Drops loot for a destroyed block using its loot table.
fn drop_block_loot(
    player: &Player,
    world: &Arc<World>,
    pos: BlockPos,
    state: BlockStateId,
    tool: &ItemStack,
    block_entity: Option<&dyn BlockEntity>,
) {
    let luck = player
        .attributes()
        .lock()
        .get_value(vanilla_attributes::LUCK)
        .unwrap_or(0.0) as f32;

    let drops = BlockLootContext::new(world, pos)
        .with_luck(luck)
        .with_tool(tool)
        .with_block_entity(block_entity)
        .get_drops(state);

    // Spawn each dropped item using the player's world reference (Arc<World>)
    for item in drops {
        if !item.is_empty() {
            player.get_world().pop_resource(pos, item);
        }
    }

    BLOCK_BEHAVIORS
        .get_behavior(state.get_block())
        .spawn_after_break(state, world, pos, tool, true);
}