shdrlib 0.1.2

//! Command module - CommandPool and CommandBuffer wrappers
//!
//! **WARNING**: CORE objects do NOT enforce lifetime dependencies.
//! Command buffers must not outlive their pool, and the pool must not outlive the device.

use crate::core::Device;
use ash::vk;
use thiserror::Error;

/// Command pool operation error
#[derive(Debug, Error)]
pub enum CommandPoolError {
    #[error("Command pool creation failed: {0}")]
    CreationFailed(vk::Result),

    #[error("Command buffer allocation failed: {0}")]
    AllocationFailed(vk::Result),

    #[error("Command pool reset failed: {0}")]
    ResetFailed(vk::Result),
}

/// Command buffer operation error
#[derive(Debug, Error)]
pub enum CommandBufferError {
    #[error("Begin recording failed: {0}")]
    BeginFailed(vk::Result),

    #[error("End recording failed: {0}")]
    EndFailed(vk::Result),

    #[error("Invalid command buffer state")]
    InvalidState,
}

/// Command pool wrapper
///
/// Allocates and manages command buffers.
///
/// # Safety
///
/// This object does NOT enforce that the device outlives it.
/// Using the pool after dropping the device causes undefined behavior.
pub struct CommandPool {
    pool: vk::CommandPool,
    family_index: u32,
}

impl CommandPool {
    /// Create a new command pool
    ///
    /// # Arguments
    ///
    /// * `device` - The device to create the pool on
    /// * `queue_family_index` - The queue family this pool will allocate for
    /// * `flags` - Pool creation flags
    ///
    /// # Errors
    ///
    /// Returns `CommandPoolError::CreationFailed` if creation fails.
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use shdrlib::core::{CommandPool, Device};
    /// use ash::vk;
    ///
    /// # fn example(device: &Device, queue_family: u32) -> Result<(), shdrlib::core::CommandPoolError> {
    /// let pool = CommandPool::new(
    ///     device,
    ///     queue_family,
    ///     vk::CommandPoolCreateFlags::RESET_COMMAND_BUFFER,
    /// )?;
    /// # Ok(())
    /// # }
    /// ```
    pub fn new(
        device: &Device,
        queue_family_index: u32,
        flags: vk::CommandPoolCreateFlags,
    ) -> Result<Self, CommandPoolError> {
        let create_info = vk::CommandPoolCreateInfo {
            queue_family_index,
            flags,
            ..Default::default()
        };

        // SAFETY: device is valid, create_info is properly initialized
        let pool = unsafe {
            device
                .handle()
                .create_command_pool(&create_info, None)
                .map_err(CommandPoolError::CreationFailed)?
        };

        Ok(Self {
            pool,
            family_index: queue_family_index,
        })
    }

    /// Get the raw Vulkan command pool handle
    #[inline]
    pub fn handle(&self) -> vk::CommandPool {
        self.pool
    }

    /// Get the queue family index this pool allocates for
    #[inline]
    pub fn family_index(&self) -> u32 {
        self.family_index
    }

    /// Allocate command buffers from the pool
    ///
    /// # Arguments
    ///
    /// * `device` - The device handle
    /// * `level` - Primary or secondary command buffer level
    /// * `count` - Number of command buffers to allocate
    ///
    /// # Errors
    ///
    /// Returns `CommandPoolError::AllocationFailed` if allocation fails.
    pub fn allocate(
        &self,
        device: &Device,
        level: vk::CommandBufferLevel,
        count: u32,
    ) -> Result<Vec<CommandBuffer>, CommandPoolError> {
        let alloc_info = vk::CommandBufferAllocateInfo {
            command_pool: self.pool,
            level,
            command_buffer_count: count,
            ..Default::default()
        };

        // SAFETY: device and pool are valid, alloc_info is properly initialized
        let buffers = unsafe {
            device
                .handle()
                .allocate_command_buffers(&alloc_info)
                .map_err(CommandPoolError::AllocationFailed)?
        };

        Ok(buffers
            .into_iter()
            .map(|buffer| CommandBuffer { buffer, level })
            .collect())
    }

    /// Allocate a single primary command buffer
    pub fn allocate_primary(&self, device: &Device) -> Result<CommandBuffer, CommandPoolError> {
        let mut buffers = self.allocate(device, vk::CommandBufferLevel::PRIMARY, 1)?;
        Ok(buffers.remove(0))
    }

    /// Allocate a single secondary command buffer
    pub fn allocate_secondary(&self, device: &Device) -> Result<CommandBuffer, CommandPoolError> {
        let mut buffers = self.allocate(device, vk::CommandBufferLevel::SECONDARY, 1)?;
        Ok(buffers.remove(0))
    }

    /// Reset the command pool
    ///
    /// This resets all command buffers allocated from the pool.
    ///
    /// # Errors
    ///
    /// Returns `CommandPoolError::ResetFailed` if reset fails.
    pub fn reset(
        &self,
        device: &Device,
        flags: vk::CommandPoolResetFlags,
    ) -> Result<(), CommandPoolError> {
        // SAFETY: device and pool are valid
        unsafe {
            device
                .handle()
                .reset_command_pool(self.pool, flags)
                .map_err(CommandPoolError::ResetFailed)
        }
    }

    /// Destroy the command pool manually
    ///
    /// # Safety
    ///
    /// The device must be the same device used to create this pool.
    /// After calling destroy(), the pool handle is invalidated.
    /// All command buffers allocated from this pool are automatically freed.
    pub fn destroy(&self, device: &Device) {
        // SAFETY: device and pool are valid
        unsafe {
            device.handle().destroy_command_pool(self.pool, None);
        }
    }
}

impl Drop for CommandPool {
    fn drop(&mut self) {
        if self.pool != vk::CommandPool::null() {
            eprintln!(
                "WARNING: CommandPool dropped without calling .destroy() - potential memory leak"
            );
        }
    }
}

/// Command buffer wrapper
///
/// Records GPU commands for execution.
///
/// # Lifecycle
///
/// **IMPORTANT**: CommandBuffer objects do NOT have a `.destroy()` method.
/// Command buffers are automatically freed when their parent CommandPool is destroyed.
/// This is standard Vulkan behavior - command buffers are pool resources.
///
/// # Safety
///
/// This object does NOT enforce that the pool outlives it.
/// Using the buffer after dropping the pool causes undefined behavior.
///
/// **IMPORTANT**: Command recording methods accept raw `vk::*` handles,
/// not CORE wrappers, to avoid borrow checker issues.
pub struct CommandBuffer {
    buffer: vk::CommandBuffer,
    level: vk::CommandBufferLevel,
}

impl CommandBuffer {
    /// Create CommandBuffer from raw handle (for EX tier usage)
    ///
    /// # Safety
    ///
    /// The handle must be valid and the level must match the actual command buffer.
    pub(crate) fn from_handle(buffer: vk::CommandBuffer, level: vk::CommandBufferLevel) -> Self {
        Self { buffer, level }
    }

    /// Get the raw Vulkan command buffer handle
    #[inline]
    pub fn handle(&self) -> vk::CommandBuffer {
        self.buffer
    }

    /// Get the command buffer level
    #[inline]
    pub fn level(&self) -> vk::CommandBufferLevel {
        self.level
    }

    /// Begin recording commands
    ///
    /// # Errors
    ///
    /// Returns `CommandBufferError::BeginFailed` if begin fails.
    pub fn begin(
        &self,
        device: &Device,
        flags: vk::CommandBufferUsageFlags,
    ) -> Result<(), CommandBufferError> {
        let begin_info = vk::CommandBufferBeginInfo {
            flags,
            ..Default::default()
        };

        // SAFETY: device and buffer are valid, begin_info is properly initialized
        unsafe {
            device
                .handle()
                .begin_command_buffer(self.buffer, &begin_info)
                .map_err(CommandBufferError::BeginFailed)
        }
    }

    /// End recording commands
    ///
    /// # Errors
    ///
    /// Returns `CommandBufferError::EndFailed` if end fails.
    pub fn end(&self, device: &Device) -> Result<(), CommandBufferError> {
        // SAFETY: device and buffer are valid
        unsafe {
            device
                .handle()
                .end_command_buffer(self.buffer)
                .map_err(CommandBufferError::EndFailed)
        }
    }

    /// Reset the command buffer
    ///
    /// # Errors
    ///
    /// Returns `CommandBufferError` if reset fails.
    pub fn reset(
        &self,
        device: &Device,
        flags: vk::CommandBufferResetFlags,
    ) -> Result<(), CommandBufferError> {
        // SAFETY: device and buffer are valid
        unsafe {
            device
                .handle()
                .reset_command_buffer(self.buffer, flags)
                .map_err(CommandBufferError::BeginFailed)
        }
    }

    // ============================================================================
    // Command Recording Methods
    // NOTE: These accept raw vk::* handles to avoid borrow checker hell
    // ============================================================================

    /// Bind a graphics or compute pipeline
    #[inline]
    pub fn bind_pipeline(
        &self,
        device: &Device,
        bind_point: vk::PipelineBindPoint,
        pipeline: vk::Pipeline,
    ) {
        // SAFETY: device, buffer, and pipeline are valid
        unsafe {
            device
                .handle()
                .cmd_bind_pipeline(self.buffer, bind_point, pipeline);
        }
    }

    /// Bind descriptor sets
    #[inline]
    pub fn bind_descriptor_sets(
        &self,
        device: &Device,
        bind_point: vk::PipelineBindPoint,
        layout: vk::PipelineLayout,
        first_set: u32,
        descriptor_sets: &[vk::DescriptorSet],
        dynamic_offsets: &[u32],
    ) {
        // SAFETY: device, buffer, layout, and sets are valid
        unsafe {
            device.handle().cmd_bind_descriptor_sets(
                self.buffer,
                bind_point,
                layout,
                first_set,
                descriptor_sets,
                dynamic_offsets,
            );
        }
    }

    /// Bind vertex buffers
    #[inline]
    pub fn bind_vertex_buffers(
        &self,
        device: &Device,
        first_binding: u32,
        buffers: &[vk::Buffer],
        offsets: &[vk::DeviceSize],
    ) {
        // SAFETY: device, buffer, and vertex buffers are valid
        unsafe {
            device
                .handle()
                .cmd_bind_vertex_buffers(self.buffer, first_binding, buffers, offsets);
        }
    }

    /// Bind an index buffer
    #[inline]
    pub fn bind_index_buffer(
        &self,
        device: &Device,
        buffer: vk::Buffer,
        offset: vk::DeviceSize,
        index_type: vk::IndexType,
    ) {
        // SAFETY: device, command buffer, and index buffer are valid
        unsafe {
            device
                .handle()
                .cmd_bind_index_buffer(self.buffer, buffer, offset, index_type);
        }
    }

    /// Draw command
    #[inline]
    pub fn draw(
        &self,
        device: &Device,
        vertex_count: u32,
        instance_count: u32,
        first_vertex: u32,
        first_instance: u32,
    ) {
        // SAFETY: device and buffer are valid
        unsafe {
            device.handle().cmd_draw(
                self.buffer,
                vertex_count,
                instance_count,
                first_vertex,
                first_instance,
            );
        }
    }

    /// Draw indexed command
    #[inline]
    pub fn draw_indexed(
        &self,
        device: &Device,
        index_count: u32,
        instance_count: u32,
        first_index: u32,
        vertex_offset: i32,
        first_instance: u32,
    ) {
        // SAFETY: device and buffer are valid
        unsafe {
            device.handle().cmd_draw_indexed(
                self.buffer,
                index_count,
                instance_count,
                first_index,
                vertex_offset,
                first_instance,
            );
        }
    }

    /// Dispatch compute work
    #[inline]
    pub fn dispatch(
        &self,
        device: &Device,
        group_count_x: u32,
        group_count_y: u32,
        group_count_z: u32,
    ) {
        // SAFETY: device and buffer are valid
        unsafe {
            device
                .handle()
                .cmd_dispatch(self.buffer, group_count_x, group_count_y, group_count_z);
        }
    }

    /// Begin dynamic rendering (Vulkan 1.3+)
    #[inline]
    pub fn begin_rendering(&self, device: &Device, rendering_info: &vk::RenderingInfo) {
        // SAFETY: device, buffer, and rendering_info are valid
        unsafe {
            device
                .handle()
                .cmd_begin_rendering(self.buffer, rendering_info);
        }
    }

    /// End dynamic rendering
    #[inline]
    pub fn end_rendering(&self, device: &Device) {
        // SAFETY: device and buffer are valid
        unsafe {
            device.handle().cmd_end_rendering(self.buffer);
        }
    }

    /// Pipeline barrier for synchronization
    ///
    /// Note: This function has many parameters by design to match Vulkan's API requirements.
    #[allow(clippy::too_many_arguments)]
    #[inline]
    pub fn pipeline_barrier(
        &self,
        device: &Device,
        src_stage_mask: vk::PipelineStageFlags,
        dst_stage_mask: vk::PipelineStageFlags,
        dependency_flags: vk::DependencyFlags,
        memory_barriers: &[vk::MemoryBarrier],
        buffer_barriers: &[vk::BufferMemoryBarrier],
        image_barriers: &[vk::ImageMemoryBarrier],
    ) {
        // SAFETY: device, buffer, and barriers are valid
        unsafe {
            device.handle().cmd_pipeline_barrier(
                self.buffer,
                src_stage_mask,
                dst_stage_mask,
                dependency_flags,
                memory_barriers,
                buffer_barriers,
                image_barriers,
            );
        }
    }

    /// Copy buffer to buffer
    #[inline]
    pub fn copy_buffer(
        &self,
        device: &Device,
        src_buffer: vk::Buffer,
        dst_buffer: vk::Buffer,
        regions: &[vk::BufferCopy],
    ) {
        // SAFETY: device, buffers, and regions are valid
        unsafe {
            device
                .handle()
                .cmd_copy_buffer(self.buffer, src_buffer, dst_buffer, regions);
        }
    }

    /// Copy buffer to image
    #[inline]
    pub fn copy_buffer_to_image(
        &self,
        device: &Device,
        src_buffer: vk::Buffer,
        dst_image: vk::Image,
        dst_image_layout: vk::ImageLayout,
        regions: &[vk::BufferImageCopy],
    ) {
        // SAFETY: device, buffer, image, and regions are valid
        unsafe {
            device.handle().cmd_copy_buffer_to_image(
                self.buffer,
                src_buffer,
                dst_image,
                dst_image_layout,
                regions,
            );
        }
    }
}

// No Drop implementation - command buffers are freed when pool is destroyed

#[cfg(test)]
mod tests {
    use super::*;
    use crate::core::{Device, DeviceCreateInfo, Instance, InstanceCreateInfo, QueueCreateInfo};

    fn create_test_device() -> (Instance, Device, u32) {
        let instance = Instance::new(InstanceCreateInfo {
            enable_validation: false,
            ..Default::default()
        })
        .unwrap();
        let physical_devices = instance.enumerate_physical_devices().unwrap();
        let physical_device = physical_devices[0];

        let graphics_family = unsafe {
            instance
                .get_physical_device_queue_family_properties(physical_device)
                .iter()
                .enumerate()
                .find(|(_, qf)| qf.queue_flags.contains(vk::QueueFlags::GRAPHICS))
                .map(|(i, _)| i as u32)
                .unwrap()
        };

        let device = Device::new(
            &instance,
            physical_device,
            DeviceCreateInfo {
                queue_create_infos: vec![QueueCreateInfo {
                    queue_family_index: graphics_family,
                    queue_count: 1,
                    queue_priorities: vec![1.0],
                }],
                ..Default::default()
            },
        )
        .unwrap();

        (instance, device, graphics_family)
    }

    #[test]
    fn test_command_pool_creation() {
        let (_instance, device, graphics_family) = create_test_device();
        let pool = CommandPool::new(
            &device,
            graphics_family,
            vk::CommandPoolCreateFlags::RESET_COMMAND_BUFFER,
        )
        .unwrap();
        assert_ne!(pool.handle(), vk::CommandPool::null());
        assert_eq!(pool.family_index(), graphics_family);
        pool.destroy(&device);
    }

    #[test]
    fn test_command_buffer_allocation() {
        let (_instance, device, graphics_family) = create_test_device();
        let pool = CommandPool::new(
            &device,
            graphics_family,
            vk::CommandPoolCreateFlags::RESET_COMMAND_BUFFER,
        )
        .unwrap();

        let buffer = pool.allocate_primary(&device).unwrap();
        assert_ne!(buffer.handle(), vk::CommandBuffer::null());
        assert_eq!(buffer.level(), vk::CommandBufferLevel::PRIMARY);

        pool.destroy(&device);
    }

    #[test]
    fn test_command_buffer_recording() {
        let (_instance, device, graphics_family) = create_test_device();
        let pool = CommandPool::new(
            &device,
            graphics_family,
            vk::CommandPoolCreateFlags::RESET_COMMAND_BUFFER,
        )
        .unwrap();

        let buffer = pool.allocate_primary(&device).unwrap();

        // Begin and end recording
        assert!(buffer
            .begin(&device, vk::CommandBufferUsageFlags::ONE_TIME_SUBMIT)
            .is_ok());
        assert!(buffer.end(&device).is_ok());

        pool.destroy(&device);
    }

    #[test]
    fn test_command_pool_reset() {
        let (_instance, device, graphics_family) = create_test_device();
        let pool = CommandPool::new(
            &device,
            graphics_family,
            vk::CommandPoolCreateFlags::RESET_COMMAND_BUFFER,
        )
        .unwrap();

        assert!(pool
            .reset(&device, vk::CommandPoolResetFlags::empty())
            .is_ok());

        pool.destroy(&device);
    }
}