package service

import (
    "fmt"
    "io"
    "net/http"
    "os"
    "strconv"
)

// ProgressWriter is a custom writer to track progress and execute a callback
type ProgressWriter struct {
    io.Writer
    Total     int64
    Progress  int64
    Callback  func(progress int64, total int64)
}

func (pw *ProgressWriter) Write(p []byte) (int, error) {
    n, err := pw.Writer.Write(p)
    if err != nil {
        return n, err
    }
    pw.Progress += int64(n)
    pw.Callback(pw.Progress, pw.Total)
    return n, nil
}

func DownloadFile(url string, filePath string, overwrite bool, callback func(progress int64, total int64)) error {
    // Check if the file exists
    if _, err := os.Stat(filePath); err == nil {
        if overwrite {
            // Overwrite the file if it exists
            if err := os.Remove(filePath); err != nil {
                return err
            }
        } else {
            return fmt.Errorf("file %s already exists", filePath)
        }
    }

    // Create the file
    out, err := os.Create(filePath)
    if err != nil {
        return err
    }
    defer out.Close()

    // Get the data
    resp, err := http.Get(url)
    if err != nil {
        return err
    }
    defer resp.Body.Close()


    // Check server response
    if resp.StatusCode != http.StatusOK {
        return fmt.Errorf("bad status: %s", resp.Status)
    }

    // Get the size
    size, err := strconv.Atoi(resp.Header.Get("Content-Length"))
    if err != nil {
        return err
    }

    // Create progress writer
    pw := &ProgressWriter{
        Writer:   out,
        Total:    int64(size),
        Callback: callback,
    }

    // Write the body to file with progress
    _, err = io.Copy(pw, resp.Body)
    if err != nil {
        return err
    }

    fmt.Println("\nDownload complete")
    return nil
}