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

// Mock infrastructure before any imports
vi.mock('../src/services/prisma', () => ({
    prisma: {
        organization: {
            findUnique: vi.fn(),
            update: vi.fn(),
        },
        usageEvent: {
            aggregate: vi.fn(),
            groupBy: vi.fn(),
            findMany: vi.fn(),
        },
    },
}));

import { prisma } from '../src/services/prisma';

// ─── Helpers ──────────────────────────────────────────────────────────────────

function makeOrgFixture(overrides: Record<string, unknown> = {}) {
    return {
        subscriptionPlan: 'STARTER',
        subscriptionStatus: 'ACTIVE',
        aiCreditsUsed: 120,
        aiCreditsLimit: 500,
        whatsappMessagesSent: 300,
        billingPeriodStart: new Date('2026-05-01'),
        ...overrides,
    };
}

function makeAggFixture(costUsd = 0.05, count = 120) {
    return {
        _sum: { costUsd, tokensIn: 80000, tokensOut: 20000 },
        _count: { id: count },
    };
}

// ─── Unit tests for billing summary logic ────────────────────────────────────

describe('Billing — summary computation', () => {
    beforeEach(() => vi.clearAllMocks());

    it('computes percentUsed correctly for STARTER plan', () => {
        const org = makeOrgFixture({ aiCreditsUsed: 425, aiCreditsLimit: 500 });
        const pct = org.aiCreditsLimit > 0
            ? Math.round((org.aiCreditsUsed / org.aiCreditsLimit) * 100)
            : 0;
        expect(pct).toBe(85);
    });

    it('caps percentUsed at 100 when over-limit', () => {
        const org = makeOrgFixture({ aiCreditsUsed: 600, aiCreditsLimit: 500 });
        const pct = Math.min(
            org.aiCreditsLimit > 0 ? Math.round((org.aiCreditsUsed / org.aiCreditsLimit) * 100) : 0,
            100
        );
        expect(pct).toBe(100);
    });

    it('converts costUsd to FCFA at 600x rate', () => {
        const costUsd = 0.05;
        const costFcfa = Math.round(costUsd * 600);
        expect(costFcfa).toBe(30);
    });

    it('plan label maps correctly', () => {
        const PLAN_LIMITS: Record<string, { label: string }> = {
            STARTER: { label: 'Démarrage' },
            GROWTH: { label: 'Croissance' },
            SCALE: { label: 'Scale' },
            ENTERPRISE: { label: 'Enterprise' },
        };
        expect(PLAN_LIMITS['GROWTH'].label).toBe('Croissance');
        expect(PLAN_LIMITS['ENTERPRISE'].label).toBe('Enterprise');
    });
});

// ─── Unit tests for billing history grouping ─────────────────────────────────

describe('Billing — history day grouping', () => {
    it('groups events by YYYY-MM-DD', () => {
        const events = [
            { type: 'AI_TEXT', costUsd: 0.01, createdAt: new Date('2026-05-10T10:00:00Z') },
            { type: 'AI_TEXT', costUsd: 0.02, createdAt: new Date('2026-05-10T15:00:00Z') },
            { type: 'WHATSAPP_SENT', costUsd: 0, createdAt: new Date('2026-05-11T08:00:00Z') },
        ] as any[];

        const byDay: Record<string, { aiCalls: number; whatsappMessages: number; costUsd: number }> = {};
        for (const e of events) {
            const day = e.createdAt.toISOString().substring(0, 10);
            if (!byDay[day]) byDay[day] = { aiCalls: 0, whatsappMessages: 0, costUsd: 0 };
            if (e.type === 'WHATSAPP_SENT') byDay[day].whatsappMessages++;
            else { byDay[day].aiCalls++; byDay[day].costUsd += e.costUsd; }
        }

        expect(byDay['2026-05-10'].aiCalls).toBe(2);
        expect(byDay['2026-05-10'].costUsd).toBeCloseTo(0.03);
        expect(byDay['2026-05-11'].whatsappMessages).toBe(1);
        expect(byDay['2026-05-11'].aiCalls).toBe(0);
    });

    it('caps history to max 90 days', () => {
        const days = Math.min(parseInt('200', 10), 90);
        expect(days).toBe(90);
    });
});

// ─── Unit tests for API key plan guard logic ──────────────────────────────────

describe('Billing — API key plan guard', () => {
    it('allows SCALE plan to set own API keys', () => {
        const allowedPlans = ['SCALE', 'ENTERPRISE'];
        expect(allowedPlans.includes('SCALE')).toBe(true);
        expect(allowedPlans.includes('ENTERPRISE')).toBe(true);
    });

    it('rejects STARTER plan from setting own API keys', () => {
        const allowedPlans = ['SCALE', 'ENTERPRISE'];
        expect(allowedPlans.includes('STARTER')).toBe(false);
        expect(allowedPlans.includes('GROWTH')).toBe(false);
    });
});

// ─── Unit tests for quota alert threshold ────────────────────────────────────

describe('Billing — quota alert threshold', () => {
    it('detects 85% threshold crossing', () => {
        const THRESHOLD = 85;
        const limit = 500;

        function crossesThreshold(creditsBefore: number, creditsAfter: number): boolean {
            const pctBefore = Math.floor((creditsBefore / limit) * 100);
            const pctAfter = Math.floor((creditsAfter / limit) * 100);
            return pctBefore < THRESHOLD && pctAfter >= THRESHOLD;
        }

        expect(crossesThreshold(424, 425)).toBe(true);  // 84% → 85%
        expect(crossesThreshold(425, 426)).toBe(false); // 85% → 85% (already crossed)
        expect(crossesThreshold(400, 410)).toBe(false); // 80% → 82% (not yet)
        expect(crossesThreshold(499, 500)).toBe(false); // 99% → 100% (already past)
    });

    it('does not alert when limit is 0', () => {
        const limit = 0;
        const pct = limit > 0 ? Math.floor((425 / limit) * 100) : 0;
        expect(pct).toBe(0); // Never alert when no limit
    });
});