/**
 * Unit tests for LayerStats.compute()
 * Validates: Requirements 19.1, 19.2, 19.4, 19.5
 */

import { describe, it, expect } from 'vitest';

// Extract the pure compute logic for testing (mirrors LayerStats.compute)
function computeLayerStats(parsedModel) {
  const nodes = (parsedModel && parsedModel.graph && parsedModel.graph.nodes) ? parsedModel.graph.nodes : [];
  const edges = (parsedModel && parsedModel.graph && parsedModel.graph.edges) ? parsedModel.graph.edges : [];
  const initializers = (parsedModel && parsedModel.initializers) ? parsedModel.initializers : [];

  const totalNodes = nodes.length;
  const totalEdges = edges.length;
  const totalInitializers = initializers.length;

  const countMap = {};
  nodes.forEach((node) => {
    const op = node.opType || 'Unknown';
    countMap[op] = (countMap[op] || 0) + 1;
  });

  const opTypeCounts = Object.entries(countMap)
    .map(([opType, count]) => ({
      opType,
      count,
      percentage: totalNodes > 0 ? parseFloat(((count / totalNodes) * 100).toFixed(1)) : 0,
    }))
    .sort((a, b) => b.count - a.count);

  return { opTypeCounts, totalNodes, totalEdges, totalInitializers };
}

describe('LayerStats.compute', () => {
  it('should count operator types correctly', () => {
    const model = {
      graph: {
        nodes: [
          { id: '1', opType: 'Conv' },
          { id: '2', opType: 'ReLU' },
          { id: '3', opType: 'Conv' },
          { id: '4', opType: 'Conv' },
          { id: '5', opType: 'ReLU' },
        ],
        edges: [{ source: '1', target: '2' }],
      },
      initializers: [{ name: 'w1' }, { name: 'w2' }],
    };

    const stats = computeLayerStats(model);

    expect(stats.totalNodes).toBe(5);
    expect(stats.totalEdges).toBe(1);
    expect(stats.totalInitializers).toBe(2);
    expect(stats.opTypeCounts).toHaveLength(2);
    // Sorted descending by count
    expect(stats.opTypeCounts[0]).toEqual({ opType: 'Conv', count: 3, percentage: 60 });
    expect(stats.opTypeCounts[1]).toEqual({ opType: 'ReLU', count: 2, percentage: 40 });
  });

  it('should return sum of counts equal to totalNodes', () => {
    const model = {
      graph: {
        nodes: [
          { id: '1', opType: 'Conv' },
          { id: '2', opType: 'BatchNorm' },
          { id: '3', opType: 'Conv' },
          { id: '4', opType: 'Add' },
        ],
        edges: [],
      },
      initializers: [],
    };

    const stats = computeLayerStats(model);
    const sumCounts = stats.opTypeCounts.reduce((s, e) => s + e.count, 0);
    expect(sumCounts).toBe(stats.totalNodes);
  });

  it('should handle empty model gracefully', () => {
    const stats = computeLayerStats({ graph: { nodes: [], edges: [] }, initializers: [] });
    expect(stats.totalNodes).toBe(0);
    expect(stats.totalEdges).toBe(0);
    expect(stats.totalInitializers).toBe(0);
    expect(stats.opTypeCounts).toHaveLength(0);
  });

  it('should handle null/undefined model', () => {
    const stats = computeLayerStats(null);
    expect(stats.totalNodes).toBe(0);
    expect(stats.opTypeCounts).toHaveLength(0);
  });

  it('should label nodes without opType as Unknown', () => {
    const model = {
      graph: { nodes: [{ id: '1' }, { id: '2', opType: '' }], edges: [] },
      initializers: [],
    };
    const stats = computeLayerStats(model);
    expect(stats.opTypeCounts).toHaveLength(1);
    expect(stats.opTypeCounts[0].opType).toBe('Unknown');
    expect(stats.opTypeCounts[0].count).toBe(2);
  });

  it('should sort by count descending', () => {
    const model = {
      graph: {
        nodes: [
          { id: '1', opType: 'A' },
          { id: '2', opType: 'B' },
          { id: '3', opType: 'B' },
          { id: '4', opType: 'C' },
          { id: '5', opType: 'C' },
          { id: '6', opType: 'C' },
        ],
        edges: [],
      },
      initializers: [],
    };
    const stats = computeLayerStats(model);
    expect(stats.opTypeCounts[0].opType).toBe('C');
    expect(stats.opTypeCounts[1].opType).toBe('B');
    expect(stats.opTypeCounts[2].opType).toBe('A');
  });

  it('should compute percentages that sum close to 100', () => {
    const model = {
      graph: {
        nodes: [
          { id: '1', opType: 'Conv' },
          { id: '2', opType: 'Conv' },
          { id: '3', opType: 'ReLU' },
        ],
        edges: [],
      },
      initializers: [],
    };
    const stats = computeLayerStats(model);
    const sumPct = stats.opTypeCounts.reduce((s, e) => s + e.percentage, 0);
    // Allow small rounding tolerance
    expect(Math.abs(sumPct - 100)).toBeLessThan(1);
  });
});