oxigdal-gpu 0.1.4

//! Vulkan-specific optimizations for cross-platform GPU computing.
//!
//! This module provides Vulkan-specific features including subgroup operations,
//! timeline semaphores, and push constants.

use crate::context::GpuContext;
use crate::error::{GpuError, GpuResult};
use std::collections::HashMap;
use tracing::{debug, info};

/// Vulkan optimization configuration.
#[derive(Debug, Clone)]
pub struct VulkanOptimizationConfig {
    /// Enable subgroup operations.
    pub enable_subgroup_ops: bool,
    /// Enable push constants.
    pub enable_push_constants: bool,
    /// Enable timeline semaphores for synchronization.
    pub enable_timeline_semaphores: bool,
    /// Descriptor set pool size.
    pub descriptor_pool_size: u32,
    /// Enable async compute.
    pub enable_async_compute: bool,
}

impl Default for VulkanOptimizationConfig {
    fn default() -> Self {
        Self {
            enable_subgroup_ops: true,
            enable_push_constants: true,
            enable_timeline_semaphores: true,
            descriptor_pool_size: 1000,
            enable_async_compute: true,
        }
    }
}

/// Vulkan feature detector.
pub struct VulkanFeatureDetector {
    features: VulkanFeatures,
}

#[derive(Debug, Clone)]
pub struct VulkanFeatures {
    /// Subgroup size (wave size).
    pub subgroup_size: u32,
    /// Supports subgroup arithmetic operations.
    pub subgroup_arithmetic: bool,
    /// Supports subgroup ballot.
    pub subgroup_ballot: bool,
    /// Supports subgroup shuffle.
    pub subgroup_shuffle: bool,
    /// Supports timeline semaphores.
    pub timeline_semaphores: bool,
    /// Maximum push constants size.
    pub max_push_constants_size: u32,
    /// Supports async compute.
    pub async_compute: bool,
}

impl Default for VulkanFeatures {
    fn default() -> Self {
        Self {
            subgroup_size: 32,
            subgroup_arithmetic: true,
            subgroup_ballot: true,
            subgroup_shuffle: true,
            timeline_semaphores: true,
            max_push_constants_size: 128,
            async_compute: true,
        }
    }
}

impl VulkanFeatureDetector {
    /// Create a new feature detector.
    pub fn new(context: &GpuContext) -> Self {
        let features = Self::detect_features(context);
        info!(
            "Vulkan features: subgroup_size={}, arithmetic={}, ballot={}, shuffle={}",
            features.subgroup_size,
            features.subgroup_arithmetic,
            features.subgroup_ballot,
            features.subgroup_shuffle
        );

        Self { features }
    }

    /// Get detected features.
    pub fn features(&self) -> &VulkanFeatures {
        &self.features
    }

    fn detect_features(_context: &GpuContext) -> VulkanFeatures {
        // In a real implementation, this would query Vulkan features
        // For now, return conservative defaults
        VulkanFeatures::default()
    }
}

/// Vulkan subgroup operations optimizer.
pub struct SubgroupOptimizer {
    features: VulkanFeatures,
    config: VulkanOptimizationConfig,
}

impl SubgroupOptimizer {
    /// Create a new subgroup optimizer.
    pub fn new(features: VulkanFeatures, config: VulkanOptimizationConfig) -> Self {
        Self { features, config }
    }

    /// Optimize shader code with subgroup operations.
    pub fn optimize_shader(&self, shader_code: &str) -> String {
        if !self.config.enable_subgroup_ops {
            return shader_code.to_string();
        }

        let mut optimized = shader_code.to_string();

        // Add subgroup size constant
        if !optimized.contains("SUBGROUP_SIZE") {
            let subgroup_decl = format!(
                "\nconst SUBGROUP_SIZE: u32 = {}u;\n",
                self.features.subgroup_size
            );
            optimized.insert_str(0, &subgroup_decl);
        }

        // Add subgroup helper functions if arithmetic is supported
        if self.features.subgroup_arithmetic {
            optimized.push_str(Self::subgroup_arithmetic_helpers());
        }

        // Add ballot helpers if supported
        if self.features.subgroup_ballot {
            optimized.push_str(Self::subgroup_ballot_helpers());
        }

        optimized
    }

    fn subgroup_arithmetic_helpers() -> &'static str {
        r#"
// Subgroup arithmetic operations (Vulkan-style)
// Note: WGSL doesn't directly expose subgroup ops yet,
// these are placeholders for future support

fn subgroup_add(value: f32) -> f32 {
    // Placeholder for subgroupAdd
    return value;
}

fn subgroup_mul(value: f32) -> f32 {
    // Placeholder for subgroupMul
    return value;
}

fn subgroup_min(value: f32) -> f32 {
    // Placeholder for subgroupMin
    return value;
}

fn subgroup_max(value: f32) -> f32 {
    // Placeholder for subgroupMax
    return value;
}

fn subgroup_inclusive_add(value: f32) -> f32 {
    // Placeholder for subgroupInclusiveAdd
    return value;
}

fn subgroup_exclusive_add(value: f32) -> f32 {
    // Placeholder for subgroupExclusiveAdd
    return value;
}
"#
    }

    fn subgroup_ballot_helpers() -> &'static str {
        r#"
// Subgroup ballot operations
fn subgroup_all(predicate: bool) -> bool {
    // Placeholder for subgroupAll
    return predicate;
}

fn subgroup_any(predicate: bool) -> bool {
    // Placeholder for subgroupAny
    return predicate;
}

fn subgroup_ballot(predicate: bool) -> u32 {
    // Placeholder for subgroupBallot
    return select(0u, 1u, predicate);
}

fn subgroup_inverse_ballot(value: u32) -> bool {
    // Placeholder for subgroupInverseBallot
    return value != 0u;
}
"#
    }
}

/// Vulkan push constants manager for fast parameter updates.
pub struct PushConstantsManager {
    max_size: u32,
    constants: HashMap<String, PushConstant>,
}

#[derive(Debug, Clone)]
struct PushConstant {
    name: String,
    offset: u32,
    size: u32,
    data: Vec<u8>,
}

impl PushConstantsManager {
    /// Create a new push constants manager.
    pub fn new(max_size: u32) -> Self {
        Self {
            max_size,
            constants: HashMap::new(),
        }
    }

    /// Register a push constant.
    ///
    /// # Errors
    ///
    /// Returns an error if constant exceeds max size.
    pub fn register(&mut self, name: String, size: u32) -> GpuResult<()> {
        let offset = self.calculate_next_offset();

        if offset + size > self.max_size {
            return Err(GpuError::invalid_buffer(format!(
                "Push constant exceeds maximum size: {} + {} > {}",
                offset, size, self.max_size
            )));
        }

        self.constants.insert(
            name.clone(),
            PushConstant {
                name,
                offset,
                size,
                data: vec![0; size as usize],
            },
        );

        Ok(())
    }

    /// Update push constant data.
    ///
    /// # Errors
    ///
    /// Returns an error if constant not found or data size mismatch.
    pub fn update(&mut self, name: &str, data: &[u8]) -> GpuResult<()> {
        let constant = self
            .constants
            .get_mut(name)
            .ok_or_else(|| GpuError::invalid_buffer("Push constant not found"))?;

        if data.len() != constant.size as usize {
            return Err(GpuError::invalid_buffer("Data size mismatch"));
        }

        constant.data.copy_from_slice(data);

        debug!("Updated push constant '{}' ({} bytes)", name, data.len());

        Ok(())
    }

    /// Get total size of all push constants.
    pub fn total_size(&self) -> u32 {
        self.constants.values().map(|c| c.size).sum()
    }

    fn calculate_next_offset(&self) -> u32 {
        self.constants
            .values()
            .map(|c| c.offset + c.size)
            .max()
            .unwrap_or(0)
    }
}

/// Descriptor set pool manager for Vulkan.
pub struct DescriptorSetPool {
    pool_size: u32,
    allocated: u32,
    free_sets: Vec<u32>,
}

impl DescriptorSetPool {
    /// Create a new descriptor set pool.
    pub fn new(pool_size: u32) -> Self {
        Self {
            pool_size,
            allocated: 0,
            free_sets: Vec::new(),
        }
    }

    /// Allocate a descriptor set.
    ///
    /// # Errors
    ///
    /// Returns an error if pool is exhausted.
    pub fn allocate(&mut self) -> GpuResult<u32> {
        if let Some(set_id) = self.free_sets.pop() {
            debug!("Reused descriptor set {}", set_id);
            return Ok(set_id);
        }

        if self.allocated >= self.pool_size {
            return Err(GpuError::internal(
                "Descriptor set pool exhausted".to_string(),
            ));
        }

        let set_id = self.allocated;
        self.allocated += 1;

        debug!("Allocated descriptor set {}", set_id);

        Ok(set_id)
    }

    /// Free a descriptor set.
    pub fn free(&mut self, set_id: u32) {
        if set_id < self.allocated {
            self.free_sets.push(set_id);
            debug!("Freed descriptor set {}", set_id);
        }
    }

    /// Reset the entire pool.
    pub fn reset(&mut self) {
        self.free_sets.clear();
        for i in 0..self.allocated {
            self.free_sets.push(i);
        }
        debug!("Reset descriptor set pool");
    }

    /// Get pool statistics.
    pub fn stats(&self) -> (u32, u32, usize) {
        (self.pool_size, self.allocated, self.free_sets.len())
    }
}

/// Timeline semaphore manager for async synchronization.
pub struct TimelineSemaphoreManager {
    semaphores: HashMap<u32, TimelineSemaphore>,
    next_id: u32,
}

#[derive(Debug, Clone)]
struct TimelineSemaphore {
    id: u32,
    value: u64,
    name: String,
}

impl TimelineSemaphoreManager {
    /// Create a new timeline semaphore manager.
    pub fn new() -> Self {
        Self {
            semaphores: HashMap::new(),
            next_id: 0,
        }
    }

    /// Create a timeline semaphore.
    pub fn create(&mut self, name: String, initial_value: u64) -> u32 {
        let id = self.next_id;
        self.next_id += 1;

        self.semaphores.insert(
            id,
            TimelineSemaphore {
                id,
                value: initial_value,
                name: name.clone(),
            },
        );

        debug!("Created timeline semaphore '{}' (ID: {})", name, id);

        id
    }

    /// Signal a semaphore with a new value.
    ///
    /// # Errors
    ///
    /// Returns an error if semaphore not found.
    pub fn signal(&mut self, id: u32, value: u64) -> GpuResult<()> {
        let sem = self
            .semaphores
            .get_mut(&id)
            .ok_or_else(|| GpuError::internal("Semaphore not found"))?;

        sem.value = value;

        debug!("Signaled semaphore '{}' with value {}", sem.name, value);

        Ok(())
    }

    /// Wait for a semaphore to reach a value.
    ///
    /// # Errors
    ///
    /// Returns an error if semaphore not found.
    pub fn wait(&self, id: u32, value: u64) -> GpuResult<bool> {
        let sem = self
            .semaphores
            .get(&id)
            .ok_or_else(|| GpuError::internal("Semaphore not found"))?;

        Ok(sem.value >= value)
    }

    /// Get current semaphore value.
    ///
    /// # Errors
    ///
    /// Returns an error if semaphore not found.
    pub fn get_value(&self, id: u32) -> GpuResult<u64> {
        let sem = self
            .semaphores
            .get(&id)
            .ok_or_else(|| GpuError::internal("Semaphore not found"))?;

        Ok(sem.value)
    }

    /// Destroy a semaphore.
    pub fn destroy(&mut self, id: u32) {
        if let Some(sem) = self.semaphores.remove(&id) {
            debug!("Destroyed timeline semaphore '{}'", sem.name);
        }
    }
}

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

/// Vulkan async compute queue manager.
pub struct AsyncComputeQueue {
    compute_queue: Option<QueueHandle>,
    graphics_queue: Option<QueueHandle>,
    transfer_queue: Option<QueueHandle>,
}

#[derive(Debug, Clone)]
struct QueueHandle {
    family_index: u32,
    queue_index: u32,
}

impl AsyncComputeQueue {
    /// Create a new async compute queue manager.
    pub fn new() -> Self {
        Self {
            compute_queue: Some(QueueHandle {
                family_index: 0,
                queue_index: 0,
            }),
            graphics_queue: Some(QueueHandle {
                family_index: 0,
                queue_index: 0,
            }),
            transfer_queue: None,
        }
    }

    /// Check if async compute is available.
    pub fn is_available(&self) -> bool {
        self.compute_queue.is_some()
    }

    /// Submit work to compute queue.
    pub fn submit_compute(&self, _commands: &[u8]) -> GpuResult<()> {
        if self.compute_queue.is_none() {
            return Err(GpuError::unsupported_operation(
                "Compute queue not available".to_string(),
            ));
        }

        // Placeholder for actual submission
        Ok(())
    }

    /// Submit work to graphics queue.
    pub fn submit_graphics(&self, _commands: &[u8]) -> GpuResult<()> {
        if self.graphics_queue.is_none() {
            return Err(GpuError::unsupported_operation(
                "Graphics queue not available".to_string(),
            ));
        }

        Ok(())
    }

    /// Submit work to transfer queue.
    pub fn submit_transfer(&self, _commands: &[u8]) -> GpuResult<()> {
        if self.transfer_queue.is_none() {
            // Fall back to graphics queue
            return self.submit_graphics(_commands);
        }

        Ok(())
    }
}

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

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_vulkan_features() {
        let features = VulkanFeatures::default();
        assert_eq!(features.subgroup_size, 32);
        assert!(features.subgroup_arithmetic);
        assert!(features.subgroup_ballot);
    }

    #[test]
    fn test_push_constants_manager() {
        let mut manager = PushConstantsManager::new(256);

        manager
            .register("view_matrix".to_string(), 64)
            .expect("Failed to register");
        manager
            .register("light_pos".to_string(), 16)
            .expect("Failed to register");

        let data = vec![0u8; 64];
        manager
            .update("view_matrix", &data)
            .expect("Failed to update");

        assert!(manager.total_size() <= 256);
    }

    #[test]
    fn test_descriptor_set_pool() {
        let mut pool = DescriptorSetPool::new(10);

        let set1 = pool.allocate().expect("Failed to allocate");
        let _set2 = pool.allocate().expect("Failed to allocate");

        pool.free(set1);

        let set3 = pool.allocate().expect("Failed to allocate");
        assert_eq!(set3, set1); // Should reuse freed set

        let (pool_size, allocated, free) = pool.stats();
        assert_eq!(pool_size, 10);
        assert_eq!(allocated, 2);
        assert_eq!(free, 0);
    }

    #[test]
    fn test_timeline_semaphore() {
        let mut manager = TimelineSemaphoreManager::new();

        let sem = manager.create("test_sem".to_string(), 0);

        manager.signal(sem, 5).expect("Failed to signal");

        assert_eq!(manager.get_value(sem).expect("Failed to get value"), 5);
        assert!(manager.wait(sem, 3).expect("Failed to wait"));
        assert!(manager.wait(sem, 5).expect("Failed to wait"));
    }

    #[test]
    fn test_async_compute_queue() {
        let queue = AsyncComputeQueue::new();
        assert!(queue.is_available());

        let commands = vec![0u8; 64];
        queue.submit_compute(&commands).expect("Failed to submit");
    }
}