package repocli

import (
	"bytes"
	"context"
	"fmt"
	"net/http"
	"strconv"
	"strings"
)

func (cli *Client) GetManifest(ctx context.Context, rawrepo, tag string) (bool, string, []byte, error) {
	var err error
	var exist bool
	var mime string
	var man []byte

	ref, err := NewRepository(rawrepo)
	if err != nil {
		return exist, mime, man, err
	}
	uri := ref.Manifest(tag)

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, uri, nil)
	if err != nil {
		return exist, mime, man, err
	}
	req.Header.Set("User-Agent", cli.userAgent)
	req.Header.Set("Accept", "*/*")
	resp, err := cli.httpClient.Do(req)
	if err != nil {
		return exist, mime, man, err
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusNotFound {
		return exist, mime, man, err
	}
	if resp.StatusCode != http.StatusOK {
		err := fmt.Errorf("Unxected response code %s", resp.Status)
		return exist, mime, man, err
	}
	contentLength := resp.Header.Get("Content-Length")
	manSize, err := strconv.ParseInt(contentLength, 10, 64)
	if err != nil {
		return exist, mime, man, err
	}
	mime = resp.Header.Get("Content-Type")
	if mime == "" {
		err := fmt.Errorf("Empty MIME type declaration")
		return exist, mime, man, err
	}
	buffer := bytes.NewBuffer(nil)
	recSize, err := Copy(ctx, buffer, resp.Body)
	if manSize != recSize {
		err := fmt.Errorf("Mismatch declared and actual body size, %d and %d", manSize, recSize)
		return exist, mime, man, err
	}
	man = buffer.Bytes()

	csum := resp.Header.Get("Docker-Content-Digest")
	if csum == "" {
		err := fmt.Errorf("Empty digest declaration")
		return exist, mime, man, err
	}
	csum = strings.ToLower(csum)
	switch DigestType(csum) {
	case SHA256:
		if csum != SHA256Digest(man) {
			err := fmt.Errorf("Mismatch digest and actual declaration")
			return exist, mime, man, err
		}
	case SHA512:
		if csum != SHA256Digest(man) {
			err := fmt.Errorf("Mismatch digest and actual declaration")
			return exist, mime, man, err
		}
	default:
		err := fmt.Errorf("Unknown digest type: %s", csum)
		return exist, mime, man, err
	}

	exist = true
	return exist, mime, man, err
}