package processor

import (
	"testing"
	"time"

	"github.com/stretchr/testify/assert"

	"apskel-pos-be/internal/constants"
	"apskel-pos-be/internal/entities"
)

func TestBudgetMetrics(t *testing.T) {
	october := &entities.GameBudget{
		Scope: constants.GameBudgetScopeGlobal, Amount: 100_000_000,
		PeriodStart: time.Date(2026, 10, 1, 0, 0, 0, 0, time.UTC), PeriodEnd: time.Date(2026, 10, 31, 0, 0, 0, 0, time.UTC),
	}
	today := time.Date(2026, 10, 21, 0, 0, 0, 0, time.UTC)

	// PRD §30: Rp100M, Rp60M realized, 10 days left, burning Rp5,5M a day → Rp115M.
	m := budgetMetrics(october, today, budgetMetricInputs{Realized: 60_000_000, RealizedWindow: 38_500_000, WindowDays: 7, RemainingDays: 10})
	assert.EqualValues(t, 40_000_000, m.Remaining)
	assert.EqualValues(t, 60, m.UtilizationPercent)
	assert.EqualValues(t, 5_500_000, m.DailyBurn)
	assert.EqualValues(t, 115_000_000, m.ForecastCost)
	assert.EqualValues(t, -15_000_000, m.ForecastRemaining)
	assert.EqualValues(t, 115, m.ForecastUtilizationPercent)
	assert.Equal(t, constants.GameBudgetCritical, m.Status, "the forecast passes the budget")
	assert.EqualValues(t, 70, *m.Thresholds.Warning, "the default when the budget sets none")
	assert.EqualValues(t, 90, *m.Thresholds.Critical)
	assert.Equal(t, "2026-10-21", m.AsOf)

	for name, tc := range map[string]struct {
		thresholds     string
		realized, burn int64
		want           string
	}{
		"quiet":                     {"", 10_000_000, 0, constants.GameBudgetHealthy},
		"forecast at warning":       {"", 30_000_000, 4_000_000, constants.GameBudgetWarning}, // 30 + 4 × 10 = 70%
		"realized at critical":      {"", 90_000_000, 0, constants.GameBudgetCritical},        // 90%
		"spent":                     {"", 100_000_000, 0, constants.GameBudgetExhausted},      // 100%
		"over":                      {"", 120_000_000, 0, constants.GameBudgetExhausted},      // 120%
		"own thresholds":            {`{"warning": 20, "critical": 50}`, 25_000_000, 0, constants.GameBudgetWarning},
		"own critical only":         {`{"critical": 30}`, 31_000_000, 0, constants.GameBudgetCritical},
		"own warning above default": {`{"warning": 80}`, 75_000_000, 0, constants.GameBudgetHealthy},
	} {
		b := *october
		b.Thresholds = entities.JSONDocument(tc.thresholds)
		m := budgetMetrics(&b, today, budgetMetricInputs{Realized: tc.realized, RealizedWindow: tc.burn * 7, WindowDays: 7, RemainingDays: 10})
		assert.Equal(t, tc.want, m.Status, name)
	}

	// Not started yet: nothing to average, the forecast is what is realized.
	m = budgetMetrics(october, time.Date(2026, 9, 20, 0, 0, 0, 0, time.UTC), budgetMetricInputs{})
	assert.Zero(t, m.ForecastCost)
	assert.Equal(t, constants.GameBudgetHealthy, m.Status)
	// A third of a rupiah per day is not lost: 10 over 3 days, 3 days left → 10 more.
	m = budgetMetrics(october, today, budgetMetricInputs{Realized: 10, RealizedWindow: 10, WindowDays: 3, RemainingDays: 3})
	assert.EqualValues(t, 20, m.ForecastCost)
	assert.EqualValues(t, 3, m.DailyBurn)
}