package imgcache

import (
	"context"
	"time"
)

// DefaultEvictionInterval is how often the background evictor checks
// cache usage against the configured limit, in addition to the
// write-pressure wakeups triggered by stores.
const DefaultEvictionInterval = 5 * time.Minute

// UsageBytes returns the total number of bytes of cache content
// tracked in the database (source content blobs plus processed
// variants). It never scans the cache directories.
func (c *Cache) UsageBytes(_ context.Context) (int64, error) {
	// Red phase: implementation follows the failing tests.
	return 0, nil
}

// EvictToLimit evicts least-recently-used cache entries until total
// tracked usage is at or below the configured MaxBytes limit. It is a
// no-op when the cache is disabled (MaxBytes zero).
func (c *Cache) EvictToLimit(_ context.Context) error {
	// Red phase: implementation follows the failing tests.
	return nil
}

// StartEviction launches the background eviction goroutine, which
// reconciles the database accounting with the cache directories once
// at startup and then evicts to the configured limit on the given
// periodic interval and on write-pressure notifications.
func (c *Cache) StartEviction(_ time.Duration) {
	// Red phase: implementation follows the failing tests.
}

// StopEviction stops the background eviction goroutine and waits for
// it to exit. It is safe to call when eviction was never started.
func (c *Cache) StopEviction() {
	// Red phase: implementation follows the failing tests.
}