package util

import (
    "os"
    "path/filepath"
    "strings"
    "time"
)

// HasExt reports whether path has one of the provided extensions (case-insensitive, with or without dot).
func HasExt(path string, exts []string) bool {
    if len(exts) == 0 {
        return true
    }
    ext := strings.ToLower(filepath.Ext(path))
    for _, e := range exts {
        e = strings.ToLower(e)
        if !strings.HasPrefix(e, ".") {
            e = "." + e
        }
        if ext == e {
            return true
        }
    }
    return false
}

// WaitForStable waits until the file size has not changed for stableFor duration.
func WaitForStable(path string, stableFor time.Duration, timeout time.Duration) error {
    start := time.Now()
    var lastSize int64 = -1
    var stableStart time.Time

    for {
        info, err := os.Stat(path)
        if err != nil {
            return err
        }
        size := info.Size()

        if size == lastSize {
            if stableStart.IsZero() {
                stableStart = time.Now()
            }
            if time.Since(stableStart) >= stableFor {
                return nil
            }
        } else {
            stableStart = time.Time{}
        }

        lastSize = size

        if time.Since(start) > timeout {
            return os.ErrDeadlineExceeded
        }

        time.Sleep(2 * time.Second)
    }
}