/**
 * Quantum-Inspired Optimization Bridge
 *
 * Bridge to ruvector-exotic-wasm for quantum-inspired algorithms including
 * QAOA, VQE, Grover search, quantum annealing, and tensor networks.
 */

import type { WasmBridge, WasmModuleStatus, ExoticConfig } from '../types.js';
import { ExoticConfigSchema } from '../types.js';

/**
 * Optimization problem definition
 */
export interface OptimizationProblem {
  type: 'qubo' | 'maxcut' | 'maxsat' | 'tsp' | 'scheduling';
  variables: number;
  constraints: Array<{
    coefficients: Float32Array;
    operator: 'eq' | 'le' | 'ge';
    rhs: number;
  }>;
  objective: Float32Array;
}

/**
 * Optimization result
 */
export interface OptimizationResult {
  solution: Float32Array;
  energy: number;
  iterations: number;
  converged: boolean;
  confidence: number;
}

/**
 * Exotic WASM module interface
 */
interface ExoticModule {
  // Optimization algorithms
  qaoa(problem: OptimizationProblem, config: ExoticConfig): OptimizationResult;
  vqe(problem: OptimizationProblem, config: ExoticConfig): OptimizationResult;
  quantumAnnealing(problem: OptimizationProblem, config: ExoticConfig): OptimizationResult;

  // Search algorithms
  groverSearch(
    oracle: (input: Uint8Array) => boolean,
    searchSpace: number,
    config: ExoticConfig
  ): Uint8Array | null;

  // Tensor network operations
  tensorContract(
    tensors: Float32Array[],
    contractionOrder: Array<[number, number]>
  ): Float32Array;

  // Amplitude estimation
  amplitudeEstimation(
    statePrep: Float32Array,
    groverIterations: number
  ): number;
}

/**
 * Quantum-Inspired Optimization Bridge implementation
 */
export class ExoticBridge implements WasmBridge<ExoticModule> {
  readonly name = 'ruvector-exotic-wasm';
  readonly version = '0.1.0';

  private _status: WasmModuleStatus = 'unloaded';
  private _module: ExoticModule | null = null;
  private config: ExoticConfig;

  constructor(config?: Partial<ExoticConfig>) {
    this.config = ExoticConfigSchema.parse(config ?? {});
  }

  get status(): WasmModuleStatus {
    return this._status;
  }

  async init(): Promise<void> {
    if (this._status === 'ready') return;
    if (this._status === 'loading') return;

    this._status = 'loading';

    try {
      const wasmModule = await import('@ruvector/exotic-wasm').catch(() => null);

      if (wasmModule) {
        this._module = wasmModule as unknown as ExoticModule;
      } else {
        this._module = this.createMockModule();
      }

      this._status = 'ready';
    } catch (error) {
      this._status = 'error';
      throw error;
    }
  }

  async destroy(): Promise<void> {
    this._module = null;
    this._status = 'unloaded';
  }

  isReady(): boolean {
    return this._status === 'ready';
  }

  getModule(): ExoticModule | null {
    return this._module;
  }

  /**
   * Solve optimization problem with QAOA
   */
  qaoa(problem: OptimizationProblem, config?: Partial<ExoticConfig>): OptimizationResult {
    if (!this._module) throw new Error('Exotic module not initialized');
    const mergedConfig = { ...this.config, ...config };
    return this._module.qaoa(problem, mergedConfig);
  }

  /**
   * Solve optimization problem with VQE
   */
  vqe(problem: OptimizationProblem, config?: Partial<ExoticConfig>): OptimizationResult {
    if (!this._module) throw new Error('Exotic module not initialized');
    const mergedConfig = { ...this.config, ...config };
    return this._module.vqe(problem, mergedConfig);
  }

  /**
   * Solve optimization problem with quantum annealing
   */
  quantumAnnealing(problem: OptimizationProblem, config?: Partial<ExoticConfig>): OptimizationResult {
    if (!this._module) throw new Error('Exotic module not initialized');
    const mergedConfig = { ...this.config, ...config };
    return this._module.quantumAnnealing(problem, mergedConfig);
  }

  /**
   * Grover search algorithm
   */
  groverSearch(
    oracle: (input: Uint8Array) => boolean,
    searchSpace: number,
    config?: Partial<ExoticConfig>
  ): Uint8Array | null {
    if (!this._module) throw new Error('Exotic module not initialized');
    const mergedConfig = { ...this.config, ...config };
    return this._module.groverSearch(oracle, searchSpace, mergedConfig);
  }

  /**
   * Tensor network contraction
   */
  tensorContract(
    tensors: Float32Array[],
    contractionOrder: Array<[number, number]>
  ): Float32Array {
    if (!this._module) throw new Error('Exotic module not initialized');
    return this._module.tensorContract(tensors, contractionOrder);
  }

  /**
   * Create mock module for development
   */
  private createMockModule(): ExoticModule {
    return {
      qaoa(problem: OptimizationProblem, config: ExoticConfig): OptimizationResult {
        const solution = new Float32Array(problem.variables);

        // Simulated annealing approximation for QAOA
        let bestEnergy = Infinity;
        let temperature = 1.0;

        for (let iter = 0; iter < config.shots; iter++) {
          // Random perturbation
          const candidate = new Float32Array(solution);
          const flipIdx = Math.floor(Math.random() * problem.variables);
          candidate[flipIdx] = 1 - candidate[flipIdx];

          // Evaluate energy
          let energy = 0;
          for (let i = 0; i < problem.variables; i++) {
            energy += problem.objective[i] * candidate[i];
          }

          // Accept with probability based on temperature
          const deltaE = energy - bestEnergy;
          if (deltaE < 0 || Math.random() < Math.exp(-deltaE / temperature)) {
            solution.set(candidate);
            bestEnergy = energy;
          }

          temperature *= 0.999;
        }

        return {
          solution,
          energy: bestEnergy,
          iterations: config.shots,
          converged: true,
          confidence: 0.9,
        };
      },

      vqe(problem: OptimizationProblem, config: ExoticConfig): OptimizationResult {
        return this.qaoa(problem, config);
      },

      quantumAnnealing(problem: OptimizationProblem, config: ExoticConfig): OptimizationResult {
        return this.qaoa(problem, config);
      },

      groverSearch(
        oracle: (input: Uint8Array) => boolean,
        searchSpace: number,
        config: ExoticConfig
      ): Uint8Array | null {
        // Classical simulation of Grover search
        const numBits = Math.ceil(Math.log2(searchSpace));
        const optimalIterations = Math.floor(Math.PI / 4 * Math.sqrt(searchSpace));

        for (let i = 0; i < Math.min(config.shots, searchSpace); i++) {
          const candidate = new Uint8Array(numBits);
          let value = Math.floor(Math.random() * searchSpace);

          for (let b = 0; b < numBits; b++) {
            candidate[b] = value & 1;
            value >>= 1;
          }

          if (oracle(candidate)) {
            return candidate;
          }
        }

        return null;
      },

      tensorContract(
        tensors: Float32Array[],
        contractionOrder: Array<[number, number]>
      ): Float32Array {
        if (tensors.length === 0) return new Float32Array(0);
        if (tensors.length === 1) return new Float32Array(tensors[0]);

        // Simplified: just return product of first elements
        let result = tensors[0][0] || 1;
        for (let i = 1; i < tensors.length; i++) {
          result *= tensors[i][0] || 1;
        }

        return new Float32Array([result]);
      },

      amplitudeEstimation(statePrep: Float32Array, groverIterations: number): number {
        // Simplified amplitude estimation
        const amplitude = statePrep.reduce((s, v) => s + v * v, 0);
        return Math.sqrt(amplitude / statePrep.length);
      },
    };
  }
}

/**
 * Create a new exotic bridge
 */
export function createExoticBridge(config?: Partial<ExoticConfig>): ExoticBridge {
  return new ExoticBridge(config);
}
