trustformers-wasm 0.2.0

//! Threads and SharedArrayBuffer support for parallel processing
//!
//! This module provides support for WebAssembly threads and SharedArrayBuffer
//! to enable true parallel processing in browser environments.

#![allow(dead_code)]
use js_sys::{Atomics, Float32Array, Int32Array, SharedArrayBuffer};
use std::format;
use std::string::String;
use std::vec::Vec;
use wasm_bindgen::prelude::*;
use web_sys::{Blob, Worker, WorkerOptions, WorkerType};

/// Thread pool manager with SharedArrayBuffer support
#[wasm_bindgen]
pub struct ThreadPool {
    workers: Vec<ThreadWorker>,
    shared_memory: Option<SharedArrayBuffer>,
    control_buffer: Option<Int32Array>,
    data_buffer: Option<Float32Array>,
    max_threads: usize,
    memory_size_mb: f64,
    is_initialized: bool,
}

/// Individual thread worker with shared memory access
struct ThreadWorker {
    worker: Worker,
    id: usize,
    is_busy: bool,
    supports_shared_memory: bool,
}

/// Thread task configuration
#[wasm_bindgen]
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum ThreadTaskType {
    /// Parallel matrix multiplication
    ParallelMatMul,
    /// Parallel element-wise operations
    ParallelElementWise,
    /// Parallel reduction operations
    ParallelReduction,
    /// Parallel convolution
    ParallelConvolution,
    /// Parallel attention computation
    ParallelAttention,
}

/// Thread synchronization primitives
#[wasm_bindgen]
pub struct ThreadSync {
    control_buffer: Int32Array,
    num_threads: usize,
}

/// Memory barriers and atomic operations
#[wasm_bindgen]
pub struct AtomicOperations;

#[wasm_bindgen]
impl ThreadPool {
    /// Create a new thread pool with SharedArrayBuffer support
    #[wasm_bindgen(constructor)]
    pub fn new(max_threads: usize, memory_size_mb: f64) -> Result<ThreadPool, JsValue> {
        if !Self::is_shared_array_buffer_supported() {
            return Err("SharedArrayBuffer is not supported in this environment".into());
        }

        if max_threads == 0 {
            return Err("Thread pool must have at least 1 thread".into());
        }

        Ok(ThreadPool {
            workers: Vec::new(),
            shared_memory: None,
            control_buffer: None,
            data_buffer: None,
            max_threads,
            memory_size_mb,
            is_initialized: false,
        })
    }

    /// Check if SharedArrayBuffer is supported
    pub fn is_shared_array_buffer_supported() -> bool {
        let js_code = r#"
            try {
                return typeof SharedArrayBuffer !== 'undefined' &&
                       typeof Atomics !== 'undefined' &&
                       typeof window !== 'undefined' &&
                       window.crossOriginIsolated;
            } catch (e) {
                return false;
            }
        "#;

        js_sys::eval(js_code)
            .map(|result| result.as_bool().unwrap_or(false))
            .unwrap_or(false)
    }

    /// Check if WebAssembly threads are supported
    pub fn is_wasm_threads_supported() -> bool {
        let js_code = r#"
            try {
                return typeof WebAssembly.Memory !== 'undefined' &&
                       WebAssembly.Memory.prototype.hasOwnProperty('shared');
            } catch (e) {
                return false;
            }
        "#;

        js_sys::eval(js_code)
            .map(|result| result.as_bool().unwrap_or(false))
            .unwrap_or(false)
    }

    /// Initialize the thread pool with shared memory
    pub async fn initialize(&mut self) -> Result<(), JsValue> {
        if self.is_initialized {
            return Ok(());
        }

        // Create SharedArrayBuffer
        let memory_bytes = (self.memory_size_mb * 1024.0 * 1024.0) as u32;
        let shared_buffer = SharedArrayBuffer::new(memory_bytes);

        // Create control buffer (for synchronization)
        let control_size = self.max_threads * 16; // 16 int32s per thread for control
        let control_buffer =
            Int32Array::new_with_byte_offset_and_length(&shared_buffer, 0, control_size as u32);

        // Create data buffer (for actual computation data)
        let data_offset = control_size * 4; // 4 bytes per int32
        let data_size = (memory_bytes - data_offset as u32) / 4; // 4 bytes per float32
        let data_buffer = Float32Array::new_with_byte_offset_and_length(
            &shared_buffer,
            data_offset as u32,
            data_size,
        );

        self.shared_memory = Some(shared_buffer);
        self.control_buffer = Some(control_buffer);
        self.data_buffer = Some(data_buffer);

        // Initialize workers
        self.create_workers().await?;

        self.is_initialized = true;
        web_sys::console::log_1(
            &format!(
                "ThreadPool initialized with {} threads and {} MB shared memory",
                self.max_threads, self.memory_size_mb
            )
            .into(),
        );

        Ok(())
    }

    /// Create worker threads
    async fn create_workers(&mut self) -> Result<(), JsValue> {
        for id in 0..self.max_threads {
            let worker = self.create_thread_worker(id).await?;
            self.workers.push(worker);
        }
        Ok(())
    }

    /// Create a single thread worker
    async fn create_thread_worker(&self, id: usize) -> Result<ThreadWorker, JsValue> {
        // Create worker with module type for SharedArrayBuffer support
        let worker_options = WorkerOptions::new();
        worker_options.set_type(WorkerType::Module);

        // Worker script that handles SharedArrayBuffer
        let worker_script = self.create_worker_script();
        // BlobPropertyBag not available in web-sys 0.3.81 - using default options
        let _blob =
            Blob::new_with_str_sequence(&js_sys::Array::of1(&worker_script.clone().into()))?;

        // Url not available in web-sys 0.3.81 - use blob URL directly
        // This may not work correctly, but it's a placeholder until proper URL API is available
        let worker_url = "data:application/javascript;charset=utf-8,".to_string() + &worker_script;
        let worker = Worker::new_with_options(&worker_url, &worker_options)?;

        // Send shared memory to worker
        if let Some(ref shared_memory) = self.shared_memory {
            let init_message = js_sys::Object::new();
            js_sys::Reflect::set(&init_message, &"type".into(), &"init".into())?;
            js_sys::Reflect::set(&init_message, &"shared_memory".into(), shared_memory)?;
            js_sys::Reflect::set(&init_message, &"worker_id".into(), &(id as f64).into())?;
            js_sys::Reflect::set(
                &init_message,
                &"num_threads".into(),
                &(self.max_threads as f64).into(),
            )?;

            worker.post_message(&init_message)?;
        }

        Ok(ThreadWorker {
            worker,
            id,
            is_busy: false,
            supports_shared_memory: true,
        })
    }

    /// Create the worker script for SharedArrayBuffer processing
    fn create_worker_script(&self) -> String {
        r#"
        let sharedMemory = null;
        let controlBuffer = null;
        let dataBuffer = null;
        let workerId = -1;
        let numThreads = 0;

        self.onmessage = function(e) {
            const { type, shared_memory, worker_id, num_threads, task } = e.data;

            if (type === 'init') {
                sharedMemory = shared_memory;
                workerId = worker_id;
                numThreads = num_threads;

                // Set up control and data buffers
                const controlSize = numThreads * 16;
                controlBuffer = new Int32Array(sharedMemory, 0, controlSize);

                const dataOffset = controlSize * 4;
                const dataSize = (sharedMemory.byteLength - dataOffset) / 4;
                dataBuffer = new Float32Array(sharedMemory, dataOffset, dataSize);

                self.postMessage({ type: 'ready', worker_id: workerId });
                return;
            }

            if (type === 'task') {
                processTask(task);
            }
        };

        function processTask(task) {
            const startTime = performance.now();
            let result = null;

            try {
                switch (task.task_type) {
                    case 'ParallelMatMul':
                        result = processParallelMatMul(task);
                        break;
                    case 'ParallelElementWise':
                        result = processParallelElementWise(task);
                        break;
                    case 'ParallelReduction':
                        result = processParallelReduction(task);
                        break;
                    default:
                        throw new Error(`Unknown task type: ${task.task_type}`);
                }

                const endTime = performance.now();
                self.postMessage({
                    type: 'task_complete',
                    task_id: task.id,
                    result: result,
                    execution_time: endTime - startTime,
                    worker_id: workerId
                });

            } catch (error) {
                self.postMessage({
                    type: 'task_error',
                    task_id: task.id,
                    error: error.message,
                    worker_id: workerId
                });
            }
        }

        function processParallelMatMul(task) {
            const { start_row, end_row, a_cols, b_cols } = task.params;
            const { a_offset, b_offset, result_offset } = task.offsets;

            // Parallel matrix multiplication using SharedArrayBuffer
            for (let i = start_row; i < end_row; i++) {
                for (let j = 0; j < b_cols; j++) {
                    let sum = 0;
                    for (let k = 0; k < a_cols; k++) {
                        const a_val = dataBuffer[a_offset + i * a_cols + k];
                        const b_val = dataBuffer[b_offset + k * b_cols + j];
                        sum += a_val * b_val;
                    }
                    dataBuffer[result_offset + i * b_cols + j] = sum;
                }
            }

            // Signal completion using atomic operations
            const controlIndex = workerId * 16;
            Atomics.store(controlBuffer, controlIndex, 1); // Mark as complete

            return { processed_rows: end_row - start_row };
        }

        function processParallelElementWise(task) {
            const { start_idx, end_idx, operation } = task.params;
            const { input_offset, output_offset } = task.offsets;

            for (let i = start_idx; i < end_idx; i++) {
                let value = dataBuffer[input_offset + i];

                switch (operation) {
                    case 'relu':
                        value = Math.max(0, value);
                        break;
                    case 'sigmoid':
                        value = 1 / (1 + Math.exp(-value));
                        break;
                    case 'tanh':
                        value = Math.tanh(value);
                        break;
                    case 'gelu':
                        value = 0.5 * value * (1 + Math.tanh(Math.sqrt(2/Math.PI) * (value + 0.044715 * Math.pow(value, 3))));
                        break;
                    default:
                        throw new Error(`Unknown operation: ${operation}`);
                }

                dataBuffer[output_offset + i] = value;
            }

            // Signal completion
            const controlIndex = workerId * 16;
            Atomics.store(controlBuffer, controlIndex, 1);

            return { processed_elements: end_idx - start_idx };
        }

        function processParallelReduction(task) {
            const { start_idx, end_idx, operation } = task.params;
            const { input_offset } = task.offsets;

            let result = 0;

            switch (operation) {
                case 'sum':
                    for (let i = start_idx; i < end_idx; i++) {
                        result += dataBuffer[input_offset + i];
                    }
                    break;
                case 'max':
                    result = -Infinity;
                    for (let i = start_idx; i < end_idx; i++) {
                        result = Math.max(result, dataBuffer[input_offset + i]);
                    }
                    break;
                case 'min':
                    result = Infinity;
                    for (let i = start_idx; i < end_idx; i++) {
                        result = Math.min(result, dataBuffer[input_offset + i]);
                    }
                    break;
                default:
                    throw new Error(`Unknown reduction operation: ${operation}`);
            }

            // Store partial result in control buffer
            const controlIndex = workerId * 16 + 1;
            const resultAsInt = new Float32Array([result]);
            const resultAsIntView = new Int32Array(resultAsInt.buffer);
            Atomics.store(controlBuffer, controlIndex, resultAsIntView[0]);

            // Signal completion
            Atomics.store(controlBuffer, workerId * 16, 1);

            return { partial_result: result };
        }
        "#.to_string()
    }

    /// Execute a parallel matrix multiplication
    pub async fn parallel_matrix_multiply(
        &mut self,
        a_data: &[f32],
        a_shape: &[usize],
        b_data: &[f32],
        b_shape: &[usize],
    ) -> Result<Vec<f32>, JsValue> {
        if !self.is_initialized {
            return Err("ThreadPool not initialized".into());
        }

        if a_shape.len() != 2 || b_shape.len() != 2 {
            return Err("Only 2D matrices are supported".into());
        }

        let (a_rows, a_cols) = (a_shape[0], a_shape[1]);
        let (b_rows, b_cols) = (b_shape[0], b_shape[1]);

        if a_cols != b_rows {
            return Err("Matrix dimensions don't match for multiplication".into());
        }

        let data_buffer = self.data_buffer.as_ref().ok_or("data_buffer should be initialized")?;

        // Copy input data to shared memory
        let a_offset = 0;
        let b_offset = a_data.len();
        let result_offset = a_data.len() + b_data.len();

        // Copy matrices to shared buffer
        for (i, &val) in a_data.iter().enumerate() {
            data_buffer.set_index(a_offset as u32 + i as u32, val);
        }
        for (i, &val) in b_data.iter().enumerate() {
            data_buffer.set_index(b_offset as u32 + i as u32, val);
        }

        // Divide work among threads
        let rows_per_thread = a_rows.div_ceil(self.max_threads);
        let _tasks: Vec<js_sys::Object> = Vec::new();

        for (thread_id, worker) in self.workers.iter().enumerate() {
            let start_row = thread_id * rows_per_thread;
            let end_row = ((thread_id + 1) * rows_per_thread).min(a_rows);

            if start_row >= end_row {
                break; // No more work for this thread
            }

            let task = js_sys::Object::new();
            js_sys::Reflect::set(&task, &"type".into(), &"task".into())?;
            js_sys::Reflect::set(&task, &"id".into(), &(thread_id as f64).into())?;
            js_sys::Reflect::set(&task, &"task_type".into(), &"ParallelMatMul".into())?;

            let params = js_sys::Object::new();
            js_sys::Reflect::set(&params, &"start_row".into(), &(start_row as f64).into())?;
            js_sys::Reflect::set(&params, &"end_row".into(), &(end_row as f64).into())?;
            js_sys::Reflect::set(&params, &"a_cols".into(), &(a_cols as f64).into())?;
            js_sys::Reflect::set(&params, &"b_cols".into(), &(b_cols as f64).into())?;
            js_sys::Reflect::set(&task, &"params".into(), &params)?;

            let offsets = js_sys::Object::new();
            js_sys::Reflect::set(&offsets, &"a_offset".into(), &(a_offset as f64).into())?;
            js_sys::Reflect::set(&offsets, &"b_offset".into(), &(b_offset as f64).into())?;
            js_sys::Reflect::set(
                &offsets,
                &"result_offset".into(),
                &(result_offset as f64).into(),
            )?;
            js_sys::Reflect::set(&task, &"offsets".into(), &offsets)?;

            worker.worker.post_message(&task)?;
        }

        // Wait for completion using atomic operations
        self.wait_for_completion().await?;

        // Read result from shared memory
        let result: Vec<f32> = (0..a_rows * b_cols)
            .map(|i| data_buffer.get_index(result_offset as u32 + i as u32))
            .collect();

        Ok(result)
    }

    /// Wait for all threads to complete using atomic operations
    async fn wait_for_completion(&self) -> Result<(), JsValue> {
        let control_buffer =
            self.control_buffer.as_ref().ok_or("control_buffer should be initialized")?;

        loop {
            let mut all_complete = true;

            for thread_id in 0..self.max_threads {
                let control_index = thread_id * 16;
                let status = Atomics::load(control_buffer, control_index as u32)?;

                if (status as f64) != 1.0 {
                    all_complete = false;
                    break;
                }
            }

            if all_complete {
                // Reset completion flags
                for thread_id in 0..self.max_threads {
                    let control_index = thread_id * 16;
                    Atomics::store(control_buffer, control_index as u32, 0)?;
                }
                break;
            }

            // Small delay to prevent busy waiting
            let promise = js_sys::Promise::resolve(&JsValue::NULL);
            wasm_bindgen_futures::JsFuture::from(promise).await?;
        }

        Ok(())
    }

    /// Get the number of threads
    #[wasm_bindgen(getter)]
    pub fn thread_count(&self) -> usize {
        self.max_threads
    }

    /// Get shared memory size in MB
    #[wasm_bindgen(getter)]
    pub fn memory_size_mb(&self) -> f64 {
        self.memory_size_mb
    }

    /// Check if the pool is initialized
    #[wasm_bindgen(getter)]
    pub fn is_initialized(&self) -> bool {
        self.is_initialized
    }

    /// Get thread utilization statistics
    pub fn get_utilization_stats(&self) -> String {
        let busy_count = self.workers.iter().filter(|w| w.is_busy).count();
        format!(
            "Threads: {}/{} busy, SharedMemory: {} MB",
            busy_count, self.max_threads, self.memory_size_mb
        )
    }
}

#[wasm_bindgen]
impl ThreadSync {
    /// Create a new thread synchronization object
    #[wasm_bindgen(constructor)]
    pub fn new(
        shared_buffer: &SharedArrayBuffer,
        num_threads: usize,
    ) -> Result<ThreadSync, JsValue> {
        let control_buffer = Int32Array::new_with_byte_offset_and_length(
            shared_buffer,
            0,
            (num_threads * 16) as u32,
        );

        Ok(ThreadSync {
            control_buffer,
            num_threads,
        })
    }

    /// Wait for all threads to reach a barrier
    pub async fn barrier(&self) -> Result<(), JsValue> {
        // Implementation of barrier synchronization using atomics
        // This would typically involve atomic increment and wait
        Ok(())
    }

    /// Signal completion of work
    pub fn signal_complete(&self, thread_id: usize) -> Result<(), JsValue> {
        if thread_id >= self.num_threads {
            return Err("Invalid thread ID".into());
        }

        let control_index = thread_id * 16;
        Atomics::store(&self.control_buffer, control_index as u32, 1)?;
        Ok(())
    }

    /// Check if all threads are complete
    pub fn all_complete(&self) -> Result<bool, JsValue> {
        for thread_id in 0..self.num_threads {
            let control_index = thread_id * 16;
            let status = Atomics::load(&self.control_buffer, control_index as u32)?;
            if (status as f64) != 1.0 {
                return Ok(false);
            }
        }
        Ok(true)
    }
}

#[wasm_bindgen]
impl AtomicOperations {
    /// Atomic add operation
    pub fn atomic_add(buffer: &Int32Array, index: u32, value: i32) -> Result<i32, JsValue> {
        let result = Atomics::add(buffer, index, value)?;
        Ok(result)
    }

    /// Atomic compare and swap
    pub fn atomic_compare_exchange(
        buffer: &Int32Array,
        index: u32,
        expected: i32,
        new_value: i32,
    ) -> Result<i32, JsValue> {
        let result = Atomics::compare_exchange(buffer, index, expected, new_value)?;
        Ok(result)
    }

    /// Memory fence operation
    pub fn memory_fence() {
        // JavaScript doesn't have explicit memory fences, but Atomics operations provide ordering
        let dummy_buffer = Int32Array::new(&SharedArrayBuffer::new(4));
        let _ = Atomics::load(&dummy_buffer, 0);
    }
}

/// Check if threads and SharedArrayBuffer are supported
#[wasm_bindgen]
pub fn is_threading_supported() -> bool {
    ThreadPool::is_shared_array_buffer_supported() && ThreadPool::is_wasm_threads_supported()
}

/// Get optimal thread count for the current environment
#[wasm_bindgen]
pub fn get_optimal_thread_count() -> usize {
    let js_code = r#"
        try {
            return navigator.hardwareConcurrency || 4;
        } catch (e) {
            return 4;
        }
    "#;

    js_sys::eval(js_code)
        .ok()
        .and_then(|result| result.as_f64())
        .map(|count| count as usize)
        .unwrap_or(4)
}

/// Get current cross-origin isolation status
#[wasm_bindgen]
pub fn is_cross_origin_isolated() -> bool {
    let js_code = r#"
        try {
            return typeof window !== 'undefined' && window.crossOriginIsolated;
        } catch (e) {
            return false;
        }
    "#;

    js_sys::eval(js_code)
        .map(|result| result.as_bool().unwrap_or(false))
        .unwrap_or(false)
}

/// Initialize threading subsystem
pub fn initialize() -> Result<(), crate::compute::ComputeError> {
    // Placeholder - actual thread pool is created when needed
    Ok(())
}

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

    #[test]
    #[cfg(target_arch = "wasm32")]
    fn test_threading_support_detection() {
        // These tests will only pass in environments with proper threading support
        let _supported = is_threading_supported();
        let _optimal_threads = get_optimal_thread_count();
        let _cross_origin = is_cross_origin_isolated();
    }
}