amari 0.9.0

//! Phase 4D: Unified Cross-Platform Verification Framework Integration
//!
//! This module demonstrates the integration of all Phase 4 verification components
//! into a unified framework that provides consistent mathematical correctness
//! guarantees across CPU, GPU, and WASM platforms while adapting to platform constraints.

use std::marker::PhantomData;
use std::time::{Duration, Instant};
use amari_core::Multivector;

// Import verification frameworks from previous phases
// (In a real implementation, these would be proper module imports)

/// Unified platform type that encompasses all target environments
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum UnifiedPlatform {
    /// Native CPU with full phantom type support
    NativeCpu,
    /// GPU with CUDA/OpenCL/WebGPU support
    Gpu {
        device_type: GpuDeviceType,
        compute_capability: u32,
        memory_gb: u32,
    },
    /// WebAssembly in browser environment
    WasmBrowser {
        js_interop: bool,
        webgl_support: bool,
        shared_memory: bool,
    },
    /// WebAssembly in Node.js environment
    WasmNode {
        worker_threads: bool,
        native_modules: bool,
    },
}

/// GPU device types for platform detection
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum GpuDeviceType {
    Discrete,
    Integrated,
    Virtual,
}

/// Unified verification error that encapsulates all platform-specific errors
#[derive(Debug, Clone)]
pub enum UnifiedVerificationError {
    /// CPU verification errors (from phantom types)
    CpuError { operation: String, details: String },
    /// GPU verification errors
    GpuError { kernel: String, thread_id: u32, details: String },
    /// WASM verification errors
    WasmError { boundary: String, js_interop: bool, details: String },
    /// Cross-platform consistency violation
    CrossPlatformInconsistency { cpu_result: String, accelerated_result: String },
    /// Platform adaptation failure
    AdaptationFailure { from_platform: String, to_platform: String, reason: String },
}

/// Unified verification configuration that adapts to platform capabilities
#[derive(Debug, Clone)]
pub struct UnifiedVerificationConfig {
    /// Primary execution platform
    pub primary_platform: UnifiedPlatform,
    /// Fallback platforms in order of preference
    pub fallback_platforms: Vec<UnifiedPlatform>,
    /// Cross-platform consistency checking level
    pub consistency_level: ConsistencyLevel,
    /// Performance budget for verification (as percentage of computation time)
    pub verification_budget_percent: f64,
    /// Enable automatic platform switching based on workload
    pub enable_adaptive_switching: bool,
    /// Mathematical precision requirements
    pub precision_requirements: PrecisionRequirements,
}

/// Cross-platform consistency checking levels
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum ConsistencyLevel {
    /// No cross-platform checking
    None,
    /// Spot check with statistical sampling
    Statistical { sample_rate: f64 },
    /// Check critical operations
    Critical,
    /// Full cross-platform validation (development mode)
    Full,
}

/// Precision requirements for mathematical operations
#[derive(Debug, Clone, Copy)]
pub struct PrecisionRequirements {
    /// Relative tolerance for floating-point comparisons
    pub relative_tolerance: f64,
    /// Absolute tolerance for near-zero values
    pub absolute_tolerance: f64,
    /// Enable exact arithmetic for critical operations
    pub exact_arithmetic: bool,
}

/// Main unified verification framework
pub struct UnifiedVerificationFramework<const P: usize, const Q: usize, const R: usize> {
    config: UnifiedVerificationConfig,
    active_platform: UnifiedPlatform,

    // Platform-specific contexts (would be actual implementations in real code)
    cpu_context: Option<CpuVerificationContext<P, Q, R>>,
    gpu_context: Option<GpuVerificationContext<P, Q, R>>,
    wasm_context: Option<WasmVerificationContext<P, Q, R>>,

    // Performance tracking
    operation_count: u64,
    platform_switches: u32,
    total_verification_time: Duration,

    _phantom: PhantomData<(P, Q, R)>,
}

// Placeholder context types (in real implementation, these would be imported)
struct CpuVerificationContext<const P: usize, const Q: usize, const R: usize> {
    strict_mode: bool,
    _phantom: PhantomData<(P, Q, R)>,
}

struct GpuVerificationContext<const P: usize, const Q: usize, const R: usize> {
    device_type: GpuDeviceType,
    _phantom: PhantomData<(P, Q, R)>,
}

struct WasmVerificationContext<const P: usize, const Q: usize, const R: usize> {
    js_interop: bool,
    _phantom: PhantomData<(P, Q, R)>,
}

impl<const P: usize, const Q: usize, const R: usize> UnifiedVerificationFramework<P, Q, R> {
    /// Create unified verification framework with platform detection
    pub async fn new(config: UnifiedVerificationConfig) -> Result<Self, UnifiedVerificationError> {
        let detected_platform = Self::detect_optimal_platform(&config).await?;

        let mut framework = Self {
            config: config.clone(),
            active_platform: detected_platform,
            cpu_context: None,
            gpu_context: None,
            wasm_context: None,
            operation_count: 0,
            platform_switches: 0,
            total_verification_time: Duration::ZERO,
            _phantom: PhantomData,
        };

        // Initialize platform-specific contexts
        framework.initialize_contexts().await?;

        Ok(framework)
    }

    /// Detect optimal platform based on configuration and runtime capabilities
    async fn detect_optimal_platform(
        config: &UnifiedVerificationConfig
    ) -> Result<UnifiedPlatform, UnifiedVerificationError> {
        // In a real implementation, this would probe for GPU availability,
        // WASM capabilities, etc.
        match config.primary_platform {
            UnifiedPlatform::NativeCpu => Ok(UnifiedPlatform::NativeCpu),
            UnifiedPlatform::Gpu { .. } => {
                // Check if GPU is available
                if Self::is_gpu_available().await {
                    Ok(config.primary_platform)
                } else {
                    // Fall back to CPU
                    Ok(UnifiedPlatform::NativeCpu)
                }
            }
            UnifiedPlatform::WasmBrowser { .. } | UnifiedPlatform::WasmNode { .. } => {
                // Check WASM environment capabilities
                if Self::is_wasm_environment().await {
                    Ok(config.primary_platform)
                } else {
                    Ok(UnifiedPlatform::NativeCpu)
                }
            }
        }
    }

    /// Check if GPU acceleration is available
    async fn is_gpu_available() -> bool {
        // Simplified check - real implementation would probe GPU APIs
        true
    }

    /// Check if running in WASM environment
    async fn is_wasm_environment() -> bool {
        // Simplified check - real implementation would check for WASM runtime
        cfg!(target_arch = "wasm32")
    }

    /// Initialize platform-specific verification contexts
    async fn initialize_contexts(&mut self) -> Result<(), UnifiedVerificationError> {
        // Always initialize CPU context as fallback
        self.cpu_context = Some(CpuVerificationContext {
            strict_mode: true,
            _phantom: PhantomData,
        });

        match self.active_platform {
            UnifiedPlatform::NativeCpu => {
                // CPU context already initialized
            }
            UnifiedPlatform::Gpu { device_type, .. } => {
                self.gpu_context = Some(GpuVerificationContext {
                    device_type,
                    _phantom: PhantomData,
                });
            }
            UnifiedPlatform::WasmBrowser { js_interop, .. } |
            UnifiedPlatform::WasmNode { .. } => {
                let js_interop = match self.active_platform {
                    UnifiedPlatform::WasmBrowser { js_interop, .. } => js_interop,
                    _ => false,
                };

                self.wasm_context = Some(WasmVerificationContext {
                    js_interop,
                    _phantom: PhantomData,
                });
            }
        }

        Ok(())
    }

    /// Perform verified operation with automatic platform selection
    pub async fn verified_operation<F, T>(
        &mut self,
        operation_name: &str,
        operation: F,
    ) -> Result<T, UnifiedVerificationError>
    where
        F: Fn(UnifiedPlatform) -> Result<T, String>,
        T: Clone + PartialEq,
    {
        let start_time = Instant::now();
        self.operation_count += 1;

        // Determine if we should switch platforms for this operation
        if self.config.enable_adaptive_switching {
            self.consider_platform_switch(operation_name).await?;
        }

        // Execute operation on active platform
        let primary_result = self.execute_on_platform(operation_name, &operation, self.active_platform).await?;

        // Cross-platform consistency checking
        let verified_result = match self.config.consistency_level {
            ConsistencyLevel::None => primary_result,
            ConsistencyLevel::Statistical { sample_rate } => {
                if self.should_cross_check(sample_rate) {
                    self.cross_platform_verify(operation_name, &operation, primary_result).await?
                } else {
                    primary_result
                }
            }
            ConsistencyLevel::Critical => {
                if self.is_critical_operation(operation_name) {
                    self.cross_platform_verify(operation_name, &operation, primary_result).await?
                } else {
                    primary_result
                }
            }
            ConsistencyLevel::Full => {
                self.cross_platform_verify(operation_name, &operation, primary_result).await?
            }
        };

        self.total_verification_time += start_time.elapsed();
        Ok(verified_result)
    }

    /// Execute operation on specific platform with appropriate verification
    async fn execute_on_platform<F, T>(
        &self,
        operation_name: &str,
        operation: &F,
        platform: UnifiedPlatform,
    ) -> Result<T, UnifiedVerificationError>
    where
        F: Fn(UnifiedPlatform) -> Result<T, String>,
    {
        match platform {
            UnifiedPlatform::NativeCpu => {
                self.execute_cpu_verified(operation_name, operation).await
            }
            UnifiedPlatform::Gpu { .. } => {
                self.execute_gpu_verified(operation_name, operation).await
            }
            UnifiedPlatform::WasmBrowser { .. } | UnifiedPlatform::WasmNode { .. } => {
                self.execute_wasm_verified(operation_name, operation).await
            }
        }
    }

    /// Execute with CPU verification (full phantom type support)
    async fn execute_cpu_verified<F, T>(
        &self,
        operation_name: &str,
        operation: &F,
    ) -> Result<T, UnifiedVerificationError>
    where
        F: Fn(UnifiedPlatform) -> Result<T, String>,
    {
        // Pre-condition verification with phantom types
        self.verify_cpu_preconditions(operation_name)?;

        // Execute operation
        let result = operation(UnifiedPlatform::NativeCpu)
            .map_err(|e| UnifiedVerificationError::CpuError {
                operation: operation_name.to_string(),
                details: e,
            })?;

        // Post-condition verification
        self.verify_cpu_postconditions(operation_name, &result)?;

        Ok(result)
    }

    /// Execute with GPU verification (boundary and kernel-level checking)
    async fn execute_gpu_verified<F, T>(
        &self,
        operation_name: &str,
        operation: &F,
    ) -> Result<T, UnifiedVerificationError>
    where
        F: Fn(UnifiedPlatform) -> Result<T, String>,
    {
        // GPU boundary verification
        self.verify_gpu_kernel_preconditions(operation_name)?;

        // Execute on GPU
        let result = operation(self.active_platform)
            .map_err(|e| UnifiedVerificationError::GpuError {
                kernel: operation_name.to_string(),
                thread_id: 0,
                details: e,
            })?;

        // GPU boundary post-verification
        self.verify_gpu_kernel_postconditions(operation_name, &result)?;

        Ok(result)
    }

    /// Execute with WASM verification (boundary and JS interop safety)
    async fn execute_wasm_verified<F, T>(
        &self,
        operation_name: &str,
        operation: &F,
    ) -> Result<T, UnifiedVerificationError>
    where
        F: Fn(UnifiedPlatform) -> Result<T, String>,
    {
        // WASM boundary verification
        self.verify_wasm_boundary_preconditions(operation_name)?;

        // Execute in WASM
        let result = operation(self.active_platform)
            .map_err(|e| UnifiedVerificationError::WasmError {
                boundary: operation_name.to_string(),
                js_interop: self.wasm_context.as_ref().map(|c| c.js_interop).unwrap_or(false),
                details: e,
            })?;

        // WASM boundary post-verification
        self.verify_wasm_boundary_postconditions(operation_name, &result)?;

        Ok(result)
    }

    /// Cross-platform consistency verification
    async fn cross_platform_verify<F, T>(
        &self,
        operation_name: &str,
        operation: &F,
        primary_result: T,
    ) -> Result<T, UnifiedVerificationError>
    where
        F: Fn(UnifiedPlatform) -> Result<T, String>,
        T: Clone + PartialEq,
    {
        // Execute same operation on CPU for reference
        if !matches!(self.active_platform, UnifiedPlatform::NativeCpu) {
            let cpu_result = self.execute_cpu_verified(operation_name, operation).await?;

            // Compare results within precision tolerance
            if !self.results_match(&primary_result, &cpu_result) {
                return Err(UnifiedVerificationError::CrossPlatformInconsistency {
                    cpu_result: format!("{:?}", cpu_result),
                    accelerated_result: format!("{:?}", primary_result),
                });
            }
        }

        Ok(primary_result)
    }

    /// Consider switching platforms based on workload characteristics
    async fn consider_platform_switch(&mut self, operation_name: &str) -> Result<(), UnifiedVerificationError> {
        // Simple heuristic - in real implementation would be more sophisticated
        if operation_name.contains("batch") && self.operation_count > 100 {
            // Switch to GPU for large batch operations
            if !matches!(self.active_platform, UnifiedPlatform::Gpu { .. }) {
                for fallback in &self.config.fallback_platforms {
                    if matches!(fallback, UnifiedPlatform::Gpu { .. }) {
                        self.active_platform = *fallback;
                        self.platform_switches += 1;
                        break;
                    }
                }
            }
        }
        Ok(())
    }

    /// Check if operation should undergo cross-platform verification
    fn should_cross_check(&self, sample_rate: f64) -> bool {
        use std::collections::hash_map::DefaultHasher;
        use std::hash::{Hash, Hasher};

        let mut hasher = DefaultHasher::new();
        self.operation_count.hash(&mut hasher);
        let hash = hasher.finish();

        (hash as f64 / u64::MAX as f64) < sample_rate
    }

    /// Check if operation is critical and requires full verification
    fn is_critical_operation(&self, operation_name: &str) -> bool {
        operation_name.contains("inverse") ||
        operation_name.contains("division") ||
        operation_name.contains("normalize") ||
        operation_name.contains("exp")
    }

    /// Compare results considering precision requirements
    fn results_match<T: PartialEq>(&self, a: &T, b: &T) -> bool {
        // Simplified comparison - real implementation would handle numerical precision
        a == b
    }

    // Placeholder verification methods (would be implemented with actual verification logic)

    fn verify_cpu_preconditions(&self, _operation_name: &str) -> Result<(), UnifiedVerificationError> {
        Ok(())
    }

    fn verify_cpu_postconditions<T>(&self, _operation_name: &str, _result: &T) -> Result<(), UnifiedVerificationError> {
        Ok(())
    }

    fn verify_gpu_kernel_preconditions(&self, _operation_name: &str) -> Result<(), UnifiedVerificationError> {
        Ok(())
    }

    fn verify_gpu_kernel_postconditions<T>(&self, _operation_name: &str, _result: &T) -> Result<(), UnifiedVerificationError> {
        Ok(())
    }

    fn verify_wasm_boundary_preconditions(&self, _operation_name: &str) -> Result<(), UnifiedVerificationError> {
        Ok(())
    }

    fn verify_wasm_boundary_postconditions<T>(&self, _operation_name: &str, _result: &T) -> Result<(), UnifiedVerificationError> {
        Ok(())
    }

    /// Get comprehensive verification statistics
    pub fn get_unified_stats(&self) -> UnifiedVerificationStats {
        UnifiedVerificationStats {
            active_platform: self.active_platform,
            total_operations: self.operation_count,
            platform_switches: self.platform_switches,
            total_verification_time: self.total_verification_time,
            average_verification_overhead: if self.operation_count > 0 {
                self.total_verification_time.as_micros() as f64 / self.operation_count as f64
            } else {
                0.0
            },
            verification_budget_utilization: self.calculate_budget_utilization(),
        }
    }

    /// Calculate verification budget utilization percentage
    fn calculate_budget_utilization(&self) -> f64 {
        // Simplified calculation - real implementation would track compute time
        50.0 // Placeholder
    }
}

/// Comprehensive verification statistics across all platforms
#[derive(Debug)]
pub struct UnifiedVerificationStats {
    pub active_platform: UnifiedPlatform,
    pub total_operations: u64,
    pub platform_switches: u32,
    pub total_verification_time: Duration,
    pub average_verification_overhead: f64,
    pub verification_budget_utilization: f64,
}

/// Unified verified multivector that works across all platforms
pub struct UnifiedVerifiedMultivector<const P: usize, const Q: usize, const R: usize> {
    inner: Multivector<P, Q, R>,
    verification_platform: UnifiedPlatform,
    verification_level: String,
    cross_platform_verified: bool,
    _phantom: PhantomData<(P, Q, R)>,
}

impl<const P: usize, const Q: usize, const R: usize> UnifiedVerifiedMultivector<P, Q, R> {
    /// Create unified verified multivector with cross-platform validation
    pub async fn new_unified_verified(
        multivector: Multivector<P, Q, R>,
        framework: &UnifiedVerificationFramework<P, Q, R>,
    ) -> Result<Self, UnifiedVerificationError> {
        // Verify mathematical properties using unified framework
        let verification_result = framework.verified_operation(
            "multivector_creation",
            |_platform| Ok(multivector)
        ).await?;

        Ok(Self {
            inner: verification_result,
            verification_platform: framework.active_platform,
            verification_level: "unified".to_string(),
            cross_platform_verified: matches!(
                framework.config.consistency_level,
                ConsistencyLevel::Critical | ConsistencyLevel::Full
            ),
            _phantom: PhantomData,
        })
    }

    /// Perform verified geometric product across platforms
    pub async fn geometric_product_unified(
        &self,
        other: &Self,
        framework: &mut UnifiedVerificationFramework<P, Q, R>,
    ) -> Result<Self, UnifiedVerificationError> {
        let operation = |_platform| {
            Ok(self.inner.geometric_product(&other.inner))
        };

        let result = framework.verified_operation("geometric_product", operation).await?;

        Ok(Self {
            inner: result,
            verification_platform: framework.active_platform,
            verification_level: "unified".to_string(),
            cross_platform_verified: self.cross_platform_verified && other.cross_platform_verified,
            _phantom: PhantomData,
        })
    }

    /// Get underlying multivector (verified across platforms)
    pub fn inner(&self) -> &Multivector<P, Q, R> {
        &self.inner
    }

    /// Check if cross-platform verification was performed
    pub fn is_cross_platform_verified(&self) -> bool {
        self.cross_platform_verified
    }

    /// Get verification platform used
    pub fn verification_platform(&self) -> UnifiedPlatform {
        self.verification_platform
    }
}

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

    #[tokio::test]
    async fn test_unified_framework_creation() {
        let config = UnifiedVerificationConfig {
            primary_platform: UnifiedPlatform::NativeCpu,
            fallback_platforms: vec![],
            consistency_level: ConsistencyLevel::Statistical { sample_rate: 0.1 },
            verification_budget_percent: 10.0,
            enable_adaptive_switching: false,
            precision_requirements: PrecisionRequirements {
                relative_tolerance: 1e-12,
                absolute_tolerance: 1e-15,
                exact_arithmetic: false,
            },
        };

        let framework = UnifiedVerificationFramework::<3, 0, 0>::new(config).await;
        assert!(framework.is_ok());
    }

    #[tokio::test]
    async fn test_cross_platform_operation() {
        let config = UnifiedVerificationConfig {
            primary_platform: UnifiedPlatform::NativeCpu,
            fallback_platforms: vec![],
            consistency_level: ConsistencyLevel::Full,
            verification_budget_percent: 20.0,
            enable_adaptive_switching: true,
            precision_requirements: PrecisionRequirements {
                relative_tolerance: 1e-6,
                absolute_tolerance: 1e-9,
                exact_arithmetic: false,
            },
        };

        let mut framework = UnifiedVerificationFramework::<3, 0, 0>::new(config).await.unwrap();

        let result = framework.verified_operation("test_operation", |_platform| {
            Ok(42)
        }).await;

        assert!(result.is_ok());
        assert_eq!(result.unwrap(), 42);
    }

    #[tokio::test]
    async fn test_unified_verified_multivector() {
        let config = UnifiedVerificationConfig {
            primary_platform: UnifiedPlatform::NativeCpu,
            fallback_platforms: vec![],
            consistency_level: ConsistencyLevel::Critical,
            verification_budget_percent: 15.0,
            enable_adaptive_switching: false,
            precision_requirements: PrecisionRequirements {
                relative_tolerance: 1e-10,
                absolute_tolerance: 1e-12,
                exact_arithmetic: true,
            },
        };

        let framework = UnifiedVerificationFramework::<3, 0, 0>::new(config).await.unwrap();
        let mv = Multivector::<3, 0, 0>::basis_vector(0);

        let verified_mv = UnifiedVerifiedMultivector::new_unified_verified(mv, &framework).await;
        assert!(verified_mv.is_ok());

        let verified = verified_mv.unwrap();
        assert!(verified.is_cross_platform_verified());
        assert_eq!(verified.verification_platform(), UnifiedPlatform::NativeCpu);
    }

    #[test]
    fn test_platform_detection() {
        // Test would verify platform detection logic
        assert!(true); // Placeholder
    }
}