/**
 * Preservation Property Tests
 * 
 * These tests verify CURRENT correct behavior on UNFIXED code.
 * They capture baseline behavior that must remain unchanged after fixes.
 * All tests should PASS on the current unfixed code.
 * 
 * Methodology: Observation-first — read source, verify existing patterns structurally.
 */

const fc = require('fast-check');
const fs = require('fs');
const path = require('path');

// ============================================================
// Helper: Read source files for structural verification
// ============================================================
const readSource = (relativePath) => {
  return fs.readFileSync(path.join(__dirname, '..', relativePath), 'utf-8');
};

// ============================================================
// 2a. Chat Preservation
// Validates: Requirements 3.7, 3.8, 3.9
// **Validates: Requirements 3.7, 3.8, 3.9**
// ============================================================
describe('2a. Chat preservation', () => {
  it('send_message handler saves message to Message collection', () => {
    const indexSource = readSource('index.js');
    // Verify Message.create is called in the send_message handler
    expect(indexSource).toContain('Message.create');
    // Verify it saves sender, receiver, order, text fields
    expect(indexSource).toContain('sender, receiver, order: orderDocId');
  });

  it('send_message handler upserts Notification for receiver', () => {
    const indexSource = readSource('index.js');
    // Verify Notification.findOneAndUpdate with upsert: true
    expect(indexSource).toContain('Notification.findOneAndUpdate');
    expect(indexSource).toContain('upsert: true');
  });

  it('send_message handler emits new_message to receiver room', () => {
    const indexSource = readSource('index.js');
    // Verify io.to(receiver).emit('new_message', ...)
    expect(indexSource).toContain("io.to(receiver).emit('new_message'");
  });

  it('send_message handler sends FCM if receiver not in chatRooms', () => {
    const indexSource = readSource('index.js');
    // Verify FCM push logic checks chatRooms
    expect(indexSource).toContain('receiverInRoom');
    expect(indexSource).toContain('sendChatPush');
    // Verify it checks if receiver is NOT in the chat room before sending
    expect(indexSource).toContain('if (!receiverInRoom)');
  });

  it('property: chat flow structure is complete for any valid message data', () => {
    fc.assert(
      fc.property(
        fc.record({
          sender: fc.hexaString({ minLength: 24, maxLength: 24 }),
          receiver: fc.hexaString({ minLength: 24, maxLength: 24 }),
          orderId: fc.hexaString({ minLength: 24, maxLength: 24 }),
          text: fc.string({ minLength: 1, maxLength: 200 }),
          senderName: fc.string({ minLength: 1, maxLength: 50 })
        }),
        (data) => {
          // Structural verification: the handler code contains the full flow
          const indexSource = readSource('index.js');
          
          // Step 1: Message persisted
          const hasMessageCreate = indexSource.includes('Message.create');
          // Step 2: Notification upserted
          const hasNotificationUpsert = indexSource.includes('Notification.findOneAndUpdate');
          // Step 3: new_message emitted
          const hasEmitNewMessage = indexSource.includes("emit('new_message'");
          // Step 4: FCM sent conditionally
          const hasFcmPush = indexSource.includes('sendChatPush');
          
          return hasMessageCreate && hasNotificationUpsert && hasEmitNewMessage && hasFcmPush;
        }
      ),
      { numRuns: 10 }
    );
  });
});

// ============================================================
// 2b. Location Preservation
// **Validates: Requirements 3.10**
// ============================================================
describe('2b. Location preservation', () => {
  it('update_location handler updates User.currentLocation', () => {
    const indexSource = readSource('index.js');
    expect(indexSource).toContain('User.findByIdAndUpdate(userId, { currentLocation:');
  });

  it('update_location handler broadcasts captain_location_updated to order clients', () => {
    const indexSource = readSource('index.js');
    expect(indexSource).toContain("emit('captain_location_updated'");
  });

  it('update_location handler broadcasts captain_location_update to admin', () => {
    const indexSource = readSource('index.js');
    // The admin broadcast uses io.emit (global) for the live map
    expect(indexSource).toContain("io.emit('captain_location_update'");
  });

  it('property: location update flow is complete for any valid coordinates', () => {
    fc.assert(
      fc.property(
        fc.record({
          userId: fc.hexaString({ minLength: 24, maxLength: 24 }),
          lat: fc.double({ min: -90, max: 90, noNaN: true }),
          lng: fc.double({ min: -180, max: 180, noNaN: true })
        }),
        (data) => {
          const indexSource = readSource('index.js');
          
          // Currently NO userId check exists — all updates go through
          // This is the behavior we observe on unfixed code
          const hasDbUpdate = indexSource.includes('User.findByIdAndUpdate(userId, { currentLocation:');
          const hasClientBroadcast = indexSource.includes("emit('captain_location_updated'");
          const hasAdminBroadcast = indexSource.includes("io.emit('captain_location_update'");
          
          return hasDbUpdate && hasClientBroadcast && hasAdminBroadcast;
        }
      ),
      { numRuns: 10 }
    );
  });
});

// ============================================================
// 2c. Order Lifecycle Preservation
// **Validates: Requirements 3.4, 3.5, 3.6**
// ============================================================
describe('2c. Order lifecycle preservation', () => {
  const validTransitions = [
    { from: 'pending', to: 'accepted', route: '/:id/accept' },
    { from: 'accepted', to: 'picked_up', route: '/:id/pickup' },
    { from: 'picked_up', to: 'delivered', route: '/:id/deliver' },
    { from: 'pending', to: 'cancelled', route: '/:id/cancel' }
  ];

  it('Order schema defines correct status enum', () => {
    const orderSource = readSource('models/Order.js');
    expect(orderSource).toContain("enum: ['pending', 'scheduled', 'accepted', 'picked_up', 'delivered', 'cancelled']");
  });

  it('accept route changes status from pending to accepted', () => {
    const ordersSource = readSource('routes/orders.js');
    // Verify the accept handler checks for pending status
    expect(ordersSource).toContain("if (order.status !== 'pending')");
    // Verify it sets status to accepted
    expect(ordersSource).toContain("order.status = 'accepted'");
  });

  it('pickup route changes status to picked_up', () => {
    const ordersSource = readSource('routes/orders.js');
    expect(ordersSource).toContain("order.status = 'picked_up'");
  });

  it('deliver route changes status to delivered', () => {
    const ordersSource = readSource('routes/orders.js');
    expect(ordersSource).toContain("order.status = 'delivered'");
  });

  it('cancel route changes status to cancelled from pending only', () => {
    const ordersSource = readSource('routes/orders.js');
    // Cancel checks that status is pending
    expect(ordersSource).toContain("if (order.status !== 'pending')");
    expect(ordersSource).toContain("order.status = 'cancelled'");
  });

  it('property: valid state transitions are all represented in routes', () => {
    fc.assert(
      fc.property(
        fc.constantFrom(...validTransitions),
        (transition) => {
          const ordersSource = readSource('routes/orders.js');
          // Each valid transition target status is set somewhere in the routes
          return ordersSource.includes(`order.status = '${transition.to}'`);
        }
      ),
      { numRuns: 10 }
    );
  });
});

// ============================================================
// 2d. Pricing Preservation
// **Validates: Requirements 3.11, 3.12, 3.13**
// ============================================================
describe('2d. Pricing preservation', () => {
  it('order creation calculates appFee and netRevenue from settings', () => {
    const ordersSource = readSource('routes/orders.js');
    // Verify pricing formula exists
    expect(ordersSource).toContain('const appFee = price * (profitPercent / 100)');
    expect(ordersSource).toContain('const netRevenue = price - appFee');
  });

  it('property: pricing formula is deterministic for any valid inputs', () => {
    fc.assert(
      fc.property(
        fc.double({ min: 0, max: 100, noNaN: true }),   // baseFare (used as price)
        fc.double({ min: 0, max: 50, noNaN: true }),    // costPerKm
        fc.double({ min: 0, max: 100, noNaN: true }),   // distance
        fc.double({ min: 0, max: 120, noNaN: true }),   // duration
        fc.double({ min: 0.01, max: 1, noNaN: true }),  // commissionRate
        (baseFare, costPerKm, distance, duration, commissionRate) => {
          // The pricing formula from the code:
          // totalFare = price (which is baseFare + costPerKm * distance + costPerMinute * duration)
          // But in the actual code, price comes pre-calculated from the client
          // The server calculates: appFee = price * commissionRate, netRevenue = price - appFee
          
          const costPerMinute = 2; // default from Settings schema
          const totalFare = baseFare + costPerKm * distance + costPerMinute * duration;
          const profitPercent = commissionRate * 100;
          const appFee = totalFare * (profitPercent / 100);
          const netRevenue = totalFare - appFee;
          
          // Verify mathematical identity: netRevenue = totalFare * (1 - commissionRate)
          const expectedNet = totalFare * (1 - commissionRate);
          
          // Allow floating point tolerance
          return Math.abs(netRevenue - expectedNet) < 0.0001;
        }
      ),
      { numRuns: 100 }
    );
  });

  it('property: appFee + netRevenue always equals totalFare', () => {
    fc.assert(
      fc.property(
        fc.double({ min: 1, max: 10000, noNaN: true }),  // price (totalFare)
        fc.double({ min: 0.01, max: 0.99, noNaN: true }), // commissionRate
        (price, commissionRate) => {
          const profitPercent = commissionRate * 100;
          const appFee = price * (profitPercent / 100);
          const netRevenue = price - appFee;
          
          // appFee + netRevenue should equal price
          return Math.abs((appFee + netRevenue) - price) < 0.0001;
        }
      ),
      { numRuns: 100 }
    );
  });
});

// ============================================================
// 2e. CORS Preservation
// **Validates: Requirements 3.14**
// ============================================================
describe('2e. CORS preservation', () => {
  const approvedOrigins = [
    'https://wassili.site',
    'https://localhost',
    'http://localhost',
    'capacitor://localhost'
  ];

  it('corsOptions includes all approved origins', () => {
    const indexSource = readSource('index.js');
    for (const origin of approvedOrigins) {
      expect(indexSource).toContain(`'${origin}'`);
    }
  });

  it('property: every approved origin is in the CORS allowed list', () => {
    fc.assert(
      fc.property(
        fc.constantFrom(...approvedOrigins),
        (origin) => {
          const indexSource = readSource('index.js');
          return indexSource.includes(`'${origin}'`);
        }
      ),
      { numRuns: 10 }
    );
  });

  it('CORS config includes credentials: true', () => {
    const indexSource = readSource('index.js');
    expect(indexSource).toContain('credentials: true');
  });
});

// ============================================================
// 2f. Settings Single-Document Preservation
// **Validates: Requirements 3.15**
// ============================================================
describe('2f. Settings single-document preservation', () => {
  it('getSettings returns newest document when one exists', () => {
    const settingsSource = readSource('models/Settings.js');
    // Verify it queries with sort by updatedAt descending
    expect(settingsSource).toContain("sort({ updatedAt: -1 })");
    // Verify it uses lean() for performance
    expect(settingsSource).toContain('.lean()');
  });

  it('getSettings creates a document if none exist', () => {
    const settingsSource = readSource('models/Settings.js');
    expect(settingsSource).toContain('if (count === 0)');
    expect(settingsSource).toContain('await this.create({})');
  });

  it('property: Settings schema has all required pricing fields with defaults', () => {
    fc.assert(
      fc.property(
        fc.constantFrom('baseFare', 'costPerKm', 'costPerMinute', 'commissionRate'),
        (field) => {
          const settingsSource = readSource('models/Settings.js');
          // Each pricing field exists in the schema
          return settingsSource.includes(`${field}:`);
        }
      ),
      { numRuns: 4 }
    );
  });

  it('Settings defaults match expected values', () => {
    const Settings = require('../models/Settings');
    const schema = Settings.schema.obj;
    
    expect(schema.baseFare.default).toBe(10);
    expect(schema.costPerKm.default).toBe(5);
    expect(schema.costPerMinute.default).toBe(2);
    expect(schema.commissionRate.default).toBe(0.15);
  });
});

// ============================================================
// 2g. JWT Valid Token Preservation
// **Validates: Requirements 3.16**
// ============================================================
describe('2g. JWT valid token preservation', () => {
  it('protect middleware verifies token with JWT_SECRET', () => {
    const authSource = readSource('middleware/authMiddleware.js');
    expect(authSource).toContain('jwt.verify(token, process.env.JWT_SECRET)');
  });

  it('protect middleware sets req.user from decoded token', () => {
    const authSource = readSource('middleware/authMiddleware.js');
    expect(authSource).toContain('req.user = await User.findById(decoded.userId)');
  });

  it('protect middleware checks Bearer token format', () => {
    const authSource = readSource('middleware/authMiddleware.js');
    expect(authSource).toContain("startsWith('Bearer')");
  });

  it('property: protect middleware structure handles any valid JWT format', () => {
    fc.assert(
      fc.property(
        fc.string({ minLength: 32, maxLength: 64 }),  // secret
        fc.hexaString({ minLength: 24, maxLength: 24 }), // userId
        (secret, userId) => {
          const authSource = readSource('middleware/authMiddleware.js');
          
          // Verify the middleware has the complete flow:
          // 1. Extract token from header
          const hasTokenExtraction = authSource.includes('authorization') && authSource.includes('Bearer');
          // 2. Verify with jwt
          const hasVerification = authSource.includes('jwt.verify');
          // 3. Set req.user
          const hasUserSet = authSource.includes('req.user');
          // 4. Call next()
          const hasNext = authSource.includes('next()');
          
          return hasTokenExtraction && hasVerification && hasUserSet && hasNext;
        }
      ),
      { numRuns: 10 }
    );
  });
});

// ============================================================
// 2h. Rate Limit Non-Auth Preservation
// **Validates: Requirements 3.17**
// ============================================================
describe('2h. Rate limit non-auth preservation', () => {
  it('global rate limiter is configured with 100 requests per 5 minutes', () => {
    const indexSource = readSource('index.js');
    // Verify windowMs: 5 * 60 * 1000
    expect(indexSource).toContain('windowMs: 5 * 60 * 1000');
    // Verify max: 100
    expect(indexSource).toContain('max: 100');
  });

  it('global rate limiter is applied to /api routes', () => {
    const indexSource = readSource('index.js');
    expect(indexSource).toContain("app.use('/api', globalLimiter, apiRoutes)");
  });

  it('property: rate limiter config values are within expected bounds', () => {
    fc.assert(
      fc.property(
        fc.integer({ min: 1, max: 200 }), // any request count
        (requestCount) => {
          const indexSource = readSource('index.js');
          // The global limiter allows 100 requests per 5 minutes
          const hasCorrectMax = indexSource.includes('max: 100');
          const hasCorrectWindow = indexSource.includes('windowMs: 5 * 60 * 1000');
          // Requests within limit (<=100) should pass through
          return hasCorrectMax && hasCorrectWindow;
        }
      ),
      { numRuns: 10 }
    );
  });
});

// ============================================================
// 2i. Multer Upload Preservation
// **Validates: Requirements 3.18**
// ============================================================
describe('2i. Multer upload preservation', () => {
  it('multer is configured with disk storage', () => {
    const uploadSource = readSource('routes/upload.js');
    expect(uploadSource).toContain('multer.diskStorage');
  });

  it('multer has file size limit of 5MB', () => {
    const uploadSource = readSource('routes/upload.js');
    expect(uploadSource).toContain('fileSize: 5 * 1024 * 1024');
  });

  it('multer file filter allows jpeg, png, webp', () => {
    const uploadSource = readSource('routes/upload.js');
    expect(uploadSource).toContain("'image/jpeg'");
    expect(uploadSource).toContain("'image/png'");
    expect(uploadSource).toContain("'image/webp'");
  });

  it('property: multer config supports all standard image types', () => {
    const allowedTypes = ['image/jpeg', 'image/png', 'image/webp'];
    
    fc.assert(
      fc.property(
        fc.constantFrom(...allowedTypes),
        (mimeType) => {
          const uploadSource = readSource('routes/upload.js');
          return uploadSource.includes(`'${mimeType}'`);
        }
      ),
      { numRuns: 3 }
    );
  });

  it('uploads are stored in categorized directories', () => {
    const uploadSource = readSource('routes/upload.js');
    expect(uploadSource).toContain("'profiles'");
    expect(uploadSource).toContain("'documents'");
    expect(uploadSource).toContain("'parcels'");
    expect(uploadSource).toContain("'places'");
  });
});

// ============================================================
// 2j. User with Email Uniqueness Preservation
// **Validates: Requirements 3.19**
// ============================================================
describe('2j. User with email uniqueness preservation', () => {
  it('User schema has email field with unique constraint', () => {
    const userSource = readSource('models/User.js');
    expect(userSource).toContain('email:');
    expect(userSource).toContain('unique: true');
  });

  it('property: email uniqueness is enforced in schema definition', () => {
    fc.assert(
      fc.property(
        fc.emailAddress(),
        (email) => {
          // Verify the schema structurally enforces uniqueness
          const User = require('../models/User');
          const emailPath = User.schema.path('email');
          // The schema has unique: true on email
          return emailPath.options.unique === true;
        }
      ),
      { numRuns: 10 }
    );
  });
});

// ============================================================
// 2k. Existing Approved Captain Preservation
// **Validates: Requirements 3.20**
// ============================================================
describe('2k. Existing approved captain preservation', () => {
  it('approvalStatus enum includes approved as valid value', () => {
    const userSource = readSource('models/User.js');
    expect(userSource).toContain("enum: ['pending', 'approved', 'rejected']");
  });

  it('property: approved is a valid enum value for approvalStatus', () => {
    fc.assert(
      fc.property(
        fc.constantFrom('pending', 'approved', 'rejected'),
        (status) => {
          const User = require('../models/User');
          const approvalPath = User.schema.path('approvalStatus');
          // All enum values are valid
          return approvalPath.enumValues.includes(status);
        }
      ),
      { numRuns: 3 }
    );
  });

  it('existing captains with approved status remain valid', () => {
    const User = require('../models/User');
    const approvalPath = User.schema.path('approvalStatus');
    // 'approved' is in the enum — existing captains won't be invalidated
    expect(approvalPath.enumValues).toContain('approved');
  });
});

// ============================================================
// 2l. Password Hashing Preservation
// **Validates: Requirements 3.21, 3.22**
// ============================================================
describe('2l. Password hashing preservation', () => {
  it('pre-save hook hashes password with bcrypt salt rounds 10', () => {
    const userSource = readSource('models/User.js');
    expect(userSource).toContain("UserSchema.pre('save'");
    expect(userSource).toContain('bcrypt.genSalt(10)');
    expect(userSource).toContain('bcrypt.hash(this.password, salt)');
  });

  it('matchPassword method uses bcrypt.compare', () => {
    const userSource = readSource('models/User.js');
    expect(userSource).toContain('matchPassword');
    expect(userSource).toContain('bcrypt.compare(enteredPassword, this.password)');
  });

  it('pre-save hook only hashes when password is modified', () => {
    const userSource = readSource('models/User.js');
    expect(userSource).toContain("if (!this.isModified('password')) return");
  });

  it('property: password hashing structure is consistent for any password input', () => {
    fc.assert(
      fc.property(
        fc.string({ minLength: 6, maxLength: 100 }),
        (password) => {
          const userSource = readSource('models/User.js');
          
          // Verify the complete hashing flow exists:
          // 1. Check if password modified
          const hasModifiedCheck = userSource.includes("isModified('password')");
          // 2. Generate salt with 10 rounds
          const hasSaltGen = userSource.includes('bcrypt.genSalt(10)');
          // 3. Hash the password
          const hasHash = userSource.includes('bcrypt.hash(this.password, salt)');
          // 4. matchPassword method exists
          const hasMatch = userSource.includes('matchPassword');
          
          return hasModifiedCheck && hasSaltGen && hasHash && hasMatch;
        }
      ),
      { numRuns: 10 }
    );
  });
});
