package repository

import (
	"context"
	"fmt"
	"time"

	"github.com/geo-platform/tenant-api/internal/tenant/repository/generated"
)

type ImageStorageUsage struct {
	UsedBytes int64
	UpdatedAt time.Time
}

type QuotaReserveResult struct {
	UsedBytes  int64
	QuotaBytes int64
}

type ImageUsageRepository interface {
	EnsureRow(ctx context.Context, tenantID int64) error
	Get(ctx context.Context, tenantID int64) (*ImageStorageUsage, error)
	Release(ctx context.Context, tenantID, releaseBytes int64) error
	AtomicReserve(ctx context.Context, tenantID, sizeBytes int64) (*QuotaReserveResult, error)
}

type imageUsageRepository struct {
	q  generated.Querier
	db generated.DBTX
}

func NewImageUsageRepository(db generated.DBTX) ImageUsageRepository {
	return &imageUsageRepository{q: newQuerier(db), db: db}
}

func (r *imageUsageRepository) EnsureRow(ctx context.Context, tenantID int64) error {
	return r.q.EnsureImageStorageUsageRow(ctx, tenantID)
}

func (r *imageUsageRepository) Get(ctx context.Context, tenantID int64) (*ImageStorageUsage, error) {
	row, err := r.q.GetImageStorageUsage(ctx, tenantID)
	if err != nil {
		return nil, err
	}
	return &ImageStorageUsage{
		UsedBytes: row.UsedBytes,
		UpdatedAt: timeFromTimestamp(row.UpdatedAt),
	}, nil
}

func (r *imageUsageRepository) Release(ctx context.Context, tenantID, releaseBytes int64) error {
	return r.q.ReleaseImageStorageQuota(ctx, generated.ReleaseImageStorageQuotaParams{
		ReleaseBytes: releaseBytes,
		TenantID:     tenantID,
	})
}

func (r *imageUsageRepository) AtomicReserve(ctx context.Context, tenantID, sizeBytes int64) (*QuotaReserveResult, error) {
	row := r.db.QueryRow(ctx, `
WITH plan AS (
	SELECT COALESCE((p.quota_policy_json ->> 'image_storage_bytes')::BIGINT, 104857600) AS quota_bytes
	FROM tenant_plan_subscriptions s
	JOIN plans p ON p.id = s.plan_id
	WHERE s.tenant_id = $1
		AND s.status = 'active'
		AND s.deleted_at IS NULL
		AND s.end_at > NOW()
	LIMIT 1
)
UPDATE tenant_image_storage_usage u
SET used_bytes = u.used_bytes + $2,
	updated_at = NOW()
FROM plan
WHERE u.tenant_id = $1
	AND u.used_bytes + $2 <= plan.quota_bytes
RETURNING u.used_bytes, plan.quota_bytes
`, tenantID, sizeBytes)

	var result QuotaReserveResult
	if err := row.Scan(&result.UsedBytes, &result.QuotaBytes); err != nil {
		return nil, fmt.Errorf("reserve image storage quota: %w", err)
	}
	return &result, nil
}