import { describe, it, expect } from 'vitest';
import {
  resolveDependencies,
  areDependenciesSatisfied,
  getBlockingDependencies,
  type DependencyResolutionResult,
} from '@automaker/dependency-resolver';
import type { Feature } from '@automaker/types';

// Helper to create test features
function createFeature(
  id: string,
  options: {
    status?: string;
    priority?: number;
    dependencies?: string[];
    category?: string;
    description?: string;
  } = {}
): Feature {
  return {
    id,
    category: options.category || 'test',
    description: options.description || `Feature ${id}`,
    status: options.status || 'backlog',
    priority: options.priority,
    dependencies: options.dependencies,
  };
}

describe('dependency-resolver.ts', () => {
  describe('resolveDependencies', () => {
    it('should handle empty feature list', () => {
      const result = resolveDependencies([]);

      expect(result.orderedFeatures).toEqual([]);
      expect(result.circularDependencies).toEqual([]);
      expect(result.missingDependencies.size).toBe(0);
      expect(result.blockedFeatures.size).toBe(0);
    });

    it('should handle features with no dependencies', () => {
      const features = [
        createFeature('f1', { priority: 1 }),
        createFeature('f2', { priority: 2 }),
        createFeature('f3', { priority: 3 }),
      ];

      const result = resolveDependencies(features);

      expect(result.orderedFeatures).toHaveLength(3);
      expect(result.orderedFeatures[0].id).toBe('f1'); // Highest priority first
      expect(result.orderedFeatures[1].id).toBe('f2');
      expect(result.orderedFeatures[2].id).toBe('f3');
      expect(result.circularDependencies).toEqual([]);
      expect(result.missingDependencies.size).toBe(0);
      expect(result.blockedFeatures.size).toBe(0);
    });

    it('should order features by dependencies (simple chain)', () => {
      const features = [
        createFeature('f3', { dependencies: ['f2'] }),
        createFeature('f1'),
        createFeature('f2', { dependencies: ['f1'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.orderedFeatures).toHaveLength(3);
      expect(result.orderedFeatures[0].id).toBe('f1');
      expect(result.orderedFeatures[1].id).toBe('f2');
      expect(result.orderedFeatures[2].id).toBe('f3');
      expect(result.circularDependencies).toEqual([]);
    });

    it('should respect priority within same dependency level', () => {
      const features = [
        createFeature('f1', { priority: 3, dependencies: ['base'] }),
        createFeature('f2', { priority: 1, dependencies: ['base'] }),
        createFeature('f3', { priority: 2, dependencies: ['base'] }),
        createFeature('base'),
      ];

      const result = resolveDependencies(features);

      expect(result.orderedFeatures[0].id).toBe('base');
      expect(result.orderedFeatures[1].id).toBe('f2'); // Priority 1
      expect(result.orderedFeatures[2].id).toBe('f3'); // Priority 2
      expect(result.orderedFeatures[3].id).toBe('f1'); // Priority 3
    });

    it('should use default priority of 2 when not specified', () => {
      const features = [
        createFeature('f1', { priority: 1 }),
        createFeature('f2'), // No priority = default 2
        createFeature('f3', { priority: 3 }),
      ];

      const result = resolveDependencies(features);

      expect(result.orderedFeatures[0].id).toBe('f1');
      expect(result.orderedFeatures[1].id).toBe('f2');
      expect(result.orderedFeatures[2].id).toBe('f3');
    });

    it('should detect missing dependencies', () => {
      const features = [
        createFeature('f1', { dependencies: ['missing1', 'missing2'] }),
        createFeature('f2', { dependencies: ['f1', 'missing3'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.missingDependencies.size).toBe(2);
      expect(result.missingDependencies.get('f1')).toEqual(['missing1', 'missing2']);
      expect(result.missingDependencies.get('f2')).toEqual(['missing3']);
      expect(result.orderedFeatures).toHaveLength(2);
    });

    it('should detect blocked features (incomplete dependencies)', () => {
      const features = [
        createFeature('f1', { status: 'in_progress' }),
        createFeature('f2', { status: 'backlog', dependencies: ['f1'] }),
        createFeature('f3', { status: 'completed' }),
        createFeature('f4', { status: 'backlog', dependencies: ['f3'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.blockedFeatures.size).toBe(1);
      expect(result.blockedFeatures.get('f2')).toEqual(['f1']);
      expect(result.blockedFeatures.has('f4')).toBe(false); // f3 is completed
    });

    it('should not block features whose dependencies are verified', () => {
      const features = [
        createFeature('f1', { status: 'verified' }),
        createFeature('f2', { status: 'backlog', dependencies: ['f1'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.blockedFeatures.size).toBe(0);
    });

    it('should detect circular dependencies (simple cycle)', () => {
      const features = [
        createFeature('f1', { dependencies: ['f2'] }),
        createFeature('f2', { dependencies: ['f1'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.circularDependencies).toHaveLength(1);
      expect(result.circularDependencies[0]).toContain('f1');
      expect(result.circularDependencies[0]).toContain('f2');
      expect(result.orderedFeatures).toHaveLength(2); // Features still included
    });

    it('should detect circular dependencies (multi-node cycle)', () => {
      const features = [
        createFeature('f1', { dependencies: ['f3'] }),
        createFeature('f2', { dependencies: ['f1'] }),
        createFeature('f3', { dependencies: ['f2'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.circularDependencies.length).toBeGreaterThan(0);
      expect(result.orderedFeatures).toHaveLength(3);
    });

    it('should handle mixed valid and circular dependencies', () => {
      const features = [
        createFeature('base'),
        createFeature('f1', { dependencies: ['base', 'f2'] }),
        createFeature('f2', { dependencies: ['f1'] }), // Circular with f1
        createFeature('f3', { dependencies: ['base'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.circularDependencies.length).toBeGreaterThan(0);
      expect(result.orderedFeatures[0].id).toBe('base');
      expect(result.orderedFeatures).toHaveLength(4);
    });

    it('should handle complex dependency graph', () => {
      const features = [
        createFeature('ui', { dependencies: ['api', 'auth'], priority: 1 }),
        createFeature('api', { dependencies: ['db'], priority: 2 }),
        createFeature('auth', { dependencies: ['db'], priority: 1 }),
        createFeature('db', { priority: 1 }),
        createFeature('tests', { dependencies: ['ui'], priority: 3 }),
      ];

      const result = resolveDependencies(features);

      const order = result.orderedFeatures.map((f) => f.id);

      expect(order[0]).toBe('db');
      expect(order.indexOf('db')).toBeLessThan(order.indexOf('api'));
      expect(order.indexOf('db')).toBeLessThan(order.indexOf('auth'));
      expect(order.indexOf('api')).toBeLessThan(order.indexOf('ui'));
      expect(order.indexOf('auth')).toBeLessThan(order.indexOf('ui'));
      expect(order.indexOf('ui')).toBeLessThan(order.indexOf('tests'));
      expect(result.circularDependencies).toEqual([]);
    });

    it('should handle features with empty dependencies array', () => {
      const features = [
        createFeature('f1', { dependencies: [] }),
        createFeature('f2', { dependencies: [] }),
      ];

      const result = resolveDependencies(features);

      expect(result.orderedFeatures).toHaveLength(2);
      expect(result.circularDependencies).toEqual([]);
      expect(result.blockedFeatures.size).toBe(0);
    });

    it('should track multiple blocking dependencies', () => {
      const features = [
        createFeature('f1', { status: 'in_progress' }),
        createFeature('f2', { status: 'backlog' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      const result = resolveDependencies(features);

      expect(result.blockedFeatures.get('f3')).toEqual(['f1', 'f2']);
    });

    it('should handle self-referencing dependency', () => {
      const features = [createFeature('f1', { dependencies: ['f1'] })];

      const result = resolveDependencies(features);

      expect(result.circularDependencies.length).toBeGreaterThan(0);
      expect(result.orderedFeatures).toHaveLength(1);
    });
  });

  describe('areDependenciesSatisfied', () => {
    it('should return true for feature with no dependencies', () => {
      const feature = createFeature('f1');
      const allFeatures = [feature];

      expect(areDependenciesSatisfied(feature, allFeatures)).toBe(true);
    });

    it('should return true for feature with empty dependencies array', () => {
      const feature = createFeature('f1', { dependencies: [] });
      const allFeatures = [feature];

      expect(areDependenciesSatisfied(feature, allFeatures)).toBe(true);
    });

    it('should return true when all dependencies are completed', () => {
      const allFeatures = [
        createFeature('f1', { status: 'completed' }),
        createFeature('f2', { status: 'completed' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(areDependenciesSatisfied(allFeatures[2], allFeatures)).toBe(true);
    });

    it('should return true when all dependencies are verified', () => {
      const allFeatures = [
        createFeature('f1', { status: 'verified' }),
        createFeature('f2', { status: 'verified' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(areDependenciesSatisfied(allFeatures[2], allFeatures)).toBe(true);
    });

    it('should return true when dependencies are mix of completed and verified', () => {
      const allFeatures = [
        createFeature('f1', { status: 'completed' }),
        createFeature('f2', { status: 'verified' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(areDependenciesSatisfied(allFeatures[2], allFeatures)).toBe(true);
    });

    it('should return false when any dependency is in_progress', () => {
      const allFeatures = [
        createFeature('f1', { status: 'completed' }),
        createFeature('f2', { status: 'in_progress' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(areDependenciesSatisfied(allFeatures[2], allFeatures)).toBe(false);
    });

    it('should return false when any dependency is in backlog', () => {
      const allFeatures = [
        createFeature('f1', { status: 'completed' }),
        createFeature('f2', { status: 'backlog' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(areDependenciesSatisfied(allFeatures[2], allFeatures)).toBe(false);
    });

    it('should return false when dependency is missing', () => {
      const allFeatures = [createFeature('f1', { status: 'backlog', dependencies: ['missing'] })];

      expect(areDependenciesSatisfied(allFeatures[0], allFeatures)).toBe(false);
    });

    it('should return false when multiple dependencies are incomplete', () => {
      const allFeatures = [
        createFeature('f1', { status: 'backlog' }),
        createFeature('f2', { status: 'in_progress' }),
        createFeature('f3', { status: 'waiting_approval' }),
        createFeature('f4', { status: 'backlog', dependencies: ['f1', 'f2', 'f3'] }),
      ];

      expect(areDependenciesSatisfied(allFeatures[3], allFeatures)).toBe(false);
    });
  });

  describe('getBlockingDependencies', () => {
    it('should return empty array for feature with no dependencies', () => {
      const feature = createFeature('f1');
      const allFeatures = [feature];

      expect(getBlockingDependencies(feature, allFeatures)).toEqual([]);
    });

    it('should return empty array for feature with empty dependencies array', () => {
      const feature = createFeature('f1', { dependencies: [] });
      const allFeatures = [feature];

      expect(getBlockingDependencies(feature, allFeatures)).toEqual([]);
    });

    it('should return empty array when all dependencies are completed', () => {
      const allFeatures = [
        createFeature('f1', { status: 'completed' }),
        createFeature('f2', { status: 'completed' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(getBlockingDependencies(allFeatures[2], allFeatures)).toEqual([]);
    });

    it('should return empty array when all dependencies are verified', () => {
      const allFeatures = [
        createFeature('f1', { status: 'verified' }),
        createFeature('f2', { status: 'verified' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(getBlockingDependencies(allFeatures[2], allFeatures)).toEqual([]);
    });

    it('should return blocking dependencies in backlog status', () => {
      const allFeatures = [
        createFeature('f1', { status: 'backlog' }),
        createFeature('f2', { status: 'completed' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(getBlockingDependencies(allFeatures[2], allFeatures)).toEqual(['f1']);
    });

    it('should return blocking dependencies in in_progress status', () => {
      const allFeatures = [
        createFeature('f1', { status: 'in_progress' }),
        createFeature('f2', { status: 'verified' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(getBlockingDependencies(allFeatures[2], allFeatures)).toEqual(['f1']);
    });

    it('should return blocking dependencies in waiting_approval status', () => {
      const allFeatures = [
        createFeature('f1', { status: 'waiting_approval' }),
        createFeature('f2', { status: 'completed' }),
        createFeature('f3', { status: 'backlog', dependencies: ['f1', 'f2'] }),
      ];

      expect(getBlockingDependencies(allFeatures[2], allFeatures)).toEqual(['f1']);
    });

    it('should return all blocking dependencies', () => {
      const allFeatures = [
        createFeature('f1', { status: 'backlog' }),
        createFeature('f2', { status: 'in_progress' }),
        createFeature('f3', { status: 'waiting_approval' }),
        createFeature('f4', { status: 'completed' }),
        createFeature('f5', { status: 'backlog', dependencies: ['f1', 'f2', 'f3', 'f4'] }),
      ];

      const blocking = getBlockingDependencies(allFeatures[4], allFeatures);
      expect(blocking).toHaveLength(3);
      expect(blocking).toContain('f1');
      expect(blocking).toContain('f2');
      expect(blocking).toContain('f3');
      expect(blocking).not.toContain('f4');
    });

    it('should handle missing dependencies', () => {
      const allFeatures = [createFeature('f1', { status: 'backlog', dependencies: ['missing'] })];

      // Missing dependencies won't be in the blocking list since they don't exist
      expect(getBlockingDependencies(allFeatures[0], allFeatures)).toEqual([]);
    });

    it('should handle mix of completed, verified, and incomplete dependencies', () => {
      const allFeatures = [
        createFeature('f1', { status: 'completed' }),
        createFeature('f2', { status: 'verified' }),
        createFeature('f3', { status: 'in_progress' }),
        createFeature('f4', { status: 'backlog' }),
        createFeature('f5', { status: 'backlog', dependencies: ['f1', 'f2', 'f3', 'f4'] }),
      ];

      const blocking = getBlockingDependencies(allFeatures[4], allFeatures);
      expect(blocking).toHaveLength(2);
      expect(blocking).toContain('f3');
      expect(blocking).toContain('f4');
    });
  });
});