package objects

import (
	"context"
	"errors"
	"fmt"
	"net/http"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/credentials"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/vaughan0/go-ini"
)

var s3CtxKey = &contextKey{"s3"}

type contextKey struct {
	name string
}

func Middleware(client *s3.Client) func(next http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			ctx := Context(r.Context(), client)
			r = r.WithContext(ctx)
			next.ServeHTTP(w, r)
		})
	}
}

func Context(ctx context.Context, client *s3.Client) context.Context {
	return context.WithValue(ctx, s3CtxKey, client)
}

func ForContext(ctx context.Context) *s3.Client {
	raw, ok := ctx.Value(s3CtxKey).(*s3.Client)
	if !ok {
		panic(fmt.Errorf("Invalid S3 context"))
	}
	return raw
}

var ErrDisabled = errors.New("object storage is not enabled for this server")

func NewClient(conf ini.File) (*s3.Client, error) {
	upstream, _ := conf.Get("objects", "s3-upstream")
	accessKey, _ := conf.Get("objects", "s3-access-key")
	secretKey, _ := conf.Get("objects", "s3-secret-key")
	if upstream == "" || accessKey == "" || secretKey == "" {
		return nil, ErrDisabled
	}
	region, ok := conf.Get("objects", "s3-region")
	if !ok {
		region = "default"
	}

	creds := credentials.NewStaticCredentialsProvider(accessKey, secretKey, "")
	return s3.NewFromConfig(aws.Config{
		Region:      region,
		Credentials: creds,
	}, func(opts *s3.Options) {
		opts.BaseEndpoint = aws.String(upstream)
	}), nil
}

func URL(conf ini.File) string {
	upstream, _ := conf.Get("objects", "s3-upstream")
	if upstream == "" {
		return ""
	}
	return "https://" + upstream
}

func Enabled(conf ini.File) bool {
	upstream, _ := conf.Get("objects", "s3-upstream")
	accessKey, _ := conf.Get("objects", "s3-access-key")
	secretKey, _ := conf.Get("objects", "s3-secret-key")
	return upstream != "" && accessKey != "" && secretKey != ""
}