package imgcache

import (
	"context"
	"database/sql"
	"math"
	"testing"
	"time"

	"sneak.berlin/go/pixa/internal/database"
)

func setupStatsTestDB(t *testing.T) *sql.DB {
	t.Helper()
	db, err := sql.Open("sqlite", ":memory:")
	if err != nil {
		t.Fatal(err)
	}
	if err := database.ApplyMigrations(db); err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { db.Close() })
	return db
}

func TestStats_HitRateIsRatio(t *testing.T) {
	db := setupStatsTestDB(t)
	dir := t.TempDir()

	cache, err := NewCache(db, CacheConfig{
		StateDir:    dir,
		CacheTTL:    time.Hour,
		NegativeTTL: 5 * time.Minute,
	})
	if err != nil {
		t.Fatal(err)
	}

	ctx := context.Background()

	// Set some hit/miss counts and a transform_count
	_, err = db.ExecContext(ctx, `
		UPDATE cache_stats SET hit_count = 75, miss_count = 25, transform_count = 9999 WHERE id = 1
	`)
	if err != nil {
		t.Fatal(err)
	}

	stats, err := cache.Stats(ctx)
	if err != nil {
		t.Fatal(err)
	}

	if stats.HitCount != 75 {
		t.Errorf("HitCount = %d, want 75", stats.HitCount)
	}
	if stats.MissCount != 25 {
		t.Errorf("MissCount = %d, want 25", stats.MissCount)
	}

	// HitRate should be 0.75, NOT 9999 (transform_count)
	expectedRate := 0.75
	if math.Abs(stats.HitRate-expectedRate) > 0.001 {
		t.Errorf("HitRate = %f, want %f (was it scanning transform_count?)", stats.HitRate, expectedRate)
	}
}

func TestStats_ZeroCounts(t *testing.T) {
	db := setupStatsTestDB(t)
	dir := t.TempDir()

	cache, err := NewCache(db, CacheConfig{
		StateDir:    dir,
		CacheTTL:    time.Hour,
		NegativeTTL: 5 * time.Minute,
	})
	if err != nil {
		t.Fatal(err)
	}

	stats, err := cache.Stats(context.Background())
	if err != nil {
		t.Fatal(err)
	}

	// With zero hits and misses, HitRate should be 0, not some garbage value
	if stats.HitRate != 0.0 {
		t.Errorf("HitRate = %f, want 0.0 for zero counts", stats.HitRate)
	}
}