package local

import (
	"crypto"
	"crypto/tls"
	"crypto/x509"
	"time"

	"github.com/go-gost/core/bypass"
	mdata "github.com/go-gost/core/metadata"
	mdutil "github.com/go-gost/x/metadata/util"
	"github.com/go-gost/x/registry"
)

type metadata struct {
	// readTimeout is the deadline for the initial protocol sniffing phase
	// (used by SnifferBuilder.ReadTimeout). After sniffing completes and
	// raw forwarding begins, this timeout no longer applies.
	// Default: 15s.
	readTimeout   time.Duration
	// idleTimeout is the idle read timeout applied to each direction of
	// the bidirectional pipe (xnet.Pipe). A value of 0 or negative disables
	// the timeout entirely, relying on TCP keepalives and context
	// cancellation to detect dead connections.
	// Default: 0 (disabled).
	idleTimeout   time.Duration
	httpKeepalive bool
	proxyProtocol int

	sniffing                    bool
	sniffingTimeout             time.Duration
	sniffingWebsocket           bool
	sniffingWebsocketSampleRate float64

	certificate *x509.Certificate
	privateKey  crypto.PrivateKey
	alpn        string
	mitmBypass  bypass.Bypass

	stateless  bool
	bufferSize int
}

func (h *forwardHandler) parseMetadata(md mdata.Metadata) (err error) {
	h.md.readTimeout = mdutil.GetDuration(md, "readTimeout")
	if h.md.readTimeout <= 0 {
		h.md.readTimeout = 15 * time.Second
	}

	h.md.idleTimeout = mdutil.GetDuration(md, "idleTimeout")
	if h.md.idleTimeout < 0 {
		h.md.idleTimeout = 0
	}

	h.md.httpKeepalive = mdutil.GetBool(md, "http.keepalive")
	h.md.proxyProtocol = mdutil.GetInt(md, "proxyProtocol")

	h.md.sniffing = mdutil.GetBool(md, "sniffing")
	h.md.sniffingTimeout = mdutil.GetDuration(md, "sniffing.timeout")
	h.md.sniffingWebsocket = mdutil.GetBool(md, "sniffing.websocket")
	h.md.sniffingWebsocketSampleRate = mdutil.GetFloat(md, "sniffing.websocket.sampleRate")

	certFile := mdutil.GetString(md, "mitm.certFile", "mitm.caCertFile")
	keyFile := mdutil.GetString(md, "mitm.keyFile", "mitm.caKeyFile")
	if certFile != "" && keyFile != "" {
		tlsCert, err := tls.LoadX509KeyPair(certFile, keyFile)
		if err != nil {
			return err
		}
		h.md.certificate = tlsCert.Leaf
		h.md.privateKey = tlsCert.PrivateKey
	}
	h.md.alpn = mdutil.GetString(md, "mitm.alpn")
	h.md.mitmBypass = registry.BypassRegistry().Get(mdutil.GetString(md, "mitm.bypass"))

	h.md.stateless = mdutil.GetBool(md, "stateless")
	h.md.bufferSize = mdutil.GetInt(md, "bufferSize", "readBufferSize", "udp.bufferSize")
	if h.md.bufferSize <= 0 {
		h.md.bufferSize = 4096
	}

	return
}
