const { expect } = require('chai');
const TestSetup = require('../setup');
const AccountScheduler = require('../../src/service/AccountScheduler');

describe('AccountScheduler Service', function() {
    let accountScheduler;
    let testDb;

    before(async function() {
        this.timeout(10000);
        
        // Setup test database and data
        await TestSetup.setupDatabase();
        await TestSetup.setupRedis();
        await TestSetup.createTestData();
        
        testDb = TestSetup.getTestDb();
        accountScheduler = new AccountScheduler();
    });

    after(async function() {
        await TestSetup.cleanup();
    });

    describe('Initialization', function() {
        it('should initialize with default configuration', function() {
            expect(accountScheduler).to.be.instanceOf(AccountScheduler);
            expect(accountScheduler.schedulingStrategy).to.equal('health_priority');
            expect(accountScheduler.isRunning).to.be.false;
        });

        it('should start and stop service correctly', async function() {
            await accountScheduler.start();
            expect(accountScheduler.isRunning).to.be.true;

            await accountScheduler.stop();
            expect(accountScheduler.isRunning).to.be.false;
        });
    });

    describe('Account Selection', function() {
        beforeEach(async function() {
            await accountScheduler.start();
        });

        afterEach(async function() {
            await accountScheduler.stop();
        });

        it('should select optimal account based on health priority', async function() {
            const taskRequirements = {
                tier: 'normal',
                messageCount: 5,
                urgency: 'medium'
            };

            const account = await accountScheduler.selectOptimalAccount(taskRequirements);
            
            expect(account).to.not.be.null;
            expect(account).to.have.property('accountId');
            expect(account).to.have.property('healthScore');
            expect(account.status).to.equal('active');
        });

        it('should exclude limited and banned accounts', async function() {
            const taskRequirements = {
                excludeStatuses: ['limited', 'banned'],
                messageCount: 3
            };

            const account = await accountScheduler.selectOptimalAccount(taskRequirements);
            
            if (account) {
                expect(['active', 'warning']).to.include(account.status);
            }
        });

        it('should respect account limits', async function() {
            const taskRequirements = {
                messageCount: 100, // Very high count
                checkLimits: true
            };

            const account = await accountScheduler.selectOptimalAccount(taskRequirements);
            
            if (account) {
                expect(account.todaySentCount + taskRequirements.messageCount).to.be.at.most(account.dailyLimit);
            }
        });
    });

    describe('Load Balancing', function() {
        beforeEach(async function() {
            await accountScheduler.start();
        });

        afterEach(async function() {
            await accountScheduler.stop();
        });

        it('should distribute tasks across multiple accounts', async function() {
            const selections = [];
            const taskRequirements = { messageCount: 1 };

            // Select accounts multiple times
            for (let i = 0; i < 5; i++) {
                const account = await accountScheduler.selectOptimalAccount(taskRequirements);
                if (account) {
                    selections.push(account.accountId);
                }
            }

            // Should have some variety in account selection
            const uniqueAccounts = new Set(selections);
            expect(uniqueAccounts.size).to.be.greaterThan(0);
        });

        it('should update account usage after task completion', async function() {
            const account = await accountScheduler.selectOptimalAccount({ messageCount: 5 });
            
            if (account) {
                const initialUsage = account.todaySentCount;
                
                await accountScheduler.updateAccountUsage(account.accountId, {
                    sentCount: 5,
                    success: true,
                    executionTime: 1500
                });

                // Verify usage was updated
                const updatedAccount = await accountScheduler.getAccountById(account.accountId);
                expect(updatedAccount.todaySentCount).to.equal(initialUsage + 5);
            }
        });
    });

    describe('Risk Assessment', function() {
        beforeEach(async function() {
            await accountScheduler.start();
        });

        afterEach(async function() {
            await accountScheduler.stop();
        });

        it('should calculate account risk score', async function() {
            const account = await accountScheduler.selectOptimalAccount({ messageCount: 1 });
            
            if (account) {
                const riskScore = accountScheduler.calculateAccountRisk(account);
                
                expect(riskScore).to.be.a('number');
                expect(riskScore).to.be.at.least(0);
                expect(riskScore).to.be.at.most(100);
            }
        });

        it('should prefer lower risk accounts', async function() {
            // Set strategy to risk-based
            accountScheduler.setSchedulingStrategy('risk_balanced');
            
            const account = await accountScheduler.selectOptimalAccount({ 
                messageCount: 1,
                riskTolerance: 'low'
            });
            
            if (account) {
                expect(account.riskScore).to.be.at.most(50); // Low to medium risk
            }
        });
    });

    describe('Error Handling', function() {
        it('should handle database connection errors gracefully', async function() {
            // Mock database error
            const originalQuery = testDb.query;
            testDb.query = () => Promise.reject(new Error('Database connection lost'));

            const account = await accountScheduler.selectOptimalAccount({ messageCount: 1 });
            expect(account).to.be.null;

            // Restore original query method
            testDb.query = originalQuery;
        });

        it('should handle empty account pool', async function() {
            // Clear all accounts
            await testDb.query('DELETE FROM accounts_pool');

            const account = await accountScheduler.selectOptimalAccount({ messageCount: 1 });
            expect(account).to.be.null;

            // Restore test data
            await TestSetup.createTestData();
        });
    });

    describe('Strategy Configuration', function() {
        beforeEach(async function() {
            await accountScheduler.start();
        });

        afterEach(async function() {
            await accountScheduler.stop();
        });

        it('should support different scheduling strategies', function() {
            const strategies = ['round_robin', 'health_priority', 'risk_balanced', 'random'];
            
            strategies.forEach(strategy => {
                accountScheduler.setSchedulingStrategy(strategy);
                expect(accountScheduler.schedulingStrategy).to.equal(strategy);
            });
        });

        it('should validate strategy parameters', function() {
            expect(() => {
                accountScheduler.setSchedulingStrategy('invalid_strategy');
            }).to.throw();
        });
    });

    describe('Performance Monitoring', function() {
        beforeEach(async function() {
            await accountScheduler.start();
        });

        afterEach(async function() {
            await accountScheduler.stop();
        });

        it('should track selection performance metrics', async function() {
            const startTime = Date.now();
            
            await accountScheduler.selectOptimalAccount({ messageCount: 1 });
            
            const endTime = Date.now();
            const duration = endTime - startTime;
            
            // Selection should be reasonably fast (under 100ms)
            expect(duration).to.be.at.most(100);
        });

        it('should provide service statistics', function() {
            const stats = accountScheduler.getServiceStats();
            
            expect(stats).to.have.property('isRunning');
            expect(stats).to.have.property('strategy');
            expect(stats).to.have.property('totalSelections');
            expect(stats.isRunning).to.be.true;
        });
    });
});