package oss

import (
	"context"
	"errors"
	"net/url"
	"strconv"
	"time"

	"git.yuntuo.hk/k2safe/go-omni/storage"
	sdk "github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
)

func (s *Store) PresignGetWithOptions(ctx context.Context, key string, ttl time.Duration, options storage.ReadOptions) (storage.ReadLink, error) {
	if err := storage.Check(ctx, key); err != nil {
		return storage.ReadLink{}, err
	}
	if ttl < time.Second || ttl > time.Hour {
		return storage.ReadLink{}, errors.New("storage/oss: TTL must be 1s..1h")
	}
	headers, err := options.ResponseHeaders()
	if err != nil {
		return storage.ReadLink{}, err
	}
	request := &sdk.GetObjectRequest{Bucket: sdk.Ptr(s.bucket), Key: sdk.Ptr(key), ResponseContentDisposition: sdk.Ptr(headers.Get("Content-Disposition")), ResponseCacheControl: sdk.Ptr(headers.Get("Cache-Control"))}
	if contentType := headers.Get("Content-Type"); contentType != "" {
		request.ResponseContentType = sdk.Ptr(contentType)
	}
	r, err := s.client.Presign(ctx, request, sdk.PresignExpires(ttl))
	if err != nil {
		return storage.ReadLink{}, err
	}
	if len(r.SignedHeaders) != 0 {
		return storage.ReadLink{}, errors.New("storage/oss: direct GET requires a signature without additional request headers")
	}
	u, err := url.Parse(r.URL)
	if err != nil {
		return storage.ReadLink{}, errors.New("storage/oss: invalid signed URL")
	}
	q := u.Query()
	var expires time.Time
	if q.Get("x-oss-signature") != "" {
		start, e := time.Parse("20060102T150405Z", q.Get("x-oss-date"))
		seconds, e2 := strconv.ParseInt(q.Get("x-oss-expires"), 10, 64)
		if e != nil || e2 != nil || seconds < 1 || seconds > 3600 {
			return storage.ReadLink{}, errors.New("storage/oss: invalid signed expiry")
		}
		expires = start.Add(time.Duration(seconds) * time.Second)
	} else {
		seconds, e := strconv.ParseInt(q.Get("Expires"), 10, 64)
		if e != nil || q.Get("Signature") == "" {
			return storage.ReadLink{}, errors.New("storage/oss: missing signed expiry")
		}
		expires = time.Unix(seconds, 0).UTC()
	}
	return storage.ReadLink{URL: r.URL, ExpiresAt: expires}, nil
}

var _ storage.ReadPresigner = (*Store)(nil)