//go:build wasm
//:build wasm

package httpproxy

import (
	"git.smesh.lol/smesh/web/common/jsbridge/callback"
	"unsafe"
)

// === Consumer-side ===

//:wasmimport bridge httpproxy_request
func wasmRequest(reqID int32, urlPtr *byte, urlLen int32, urlCap int32, priority int32)

//:wasmimport bridge httpproxy_request_cancel
func wasmRequestCancel(reqID int32)

type fetchHandler struct {
	onOK   func(string, string)
	onFail func(int32, string)
}

var pendingFetches = map[int32]fetchHandler{}

func Request(reqID int32, url string, priority int32,
	onOK func(blobURL, contentType string),
	onFail func(status int32, errMsg string)) {
	pendingFetches[reqID] = fetchHandler{onOK: onOK, onFail: onFail}
	wasmRequest(reqID, unsafe.StringData(url), int32(len(url)), int32(len(url)), priority)
}

func RequestCancel(reqID int32) {
	delete(pendingFetches, reqID)
	wasmRequestCancel(reqID)
}

// __httpproxy_result_ok is the wasm export the supervisor calls when a
// fetch succeeds. blobURL and contentType are the result strings.
//
//:wasmexport __httpproxy_result_ok
func httpproxyResultOK(reqID int32, blobPtr *byte, blobLen int32, ctPtr *byte, ctLen int32) {
	h, ok := pendingFetches[reqID]
	if !ok {
		return
	}
	delete(pendingFetches, reqID)
	blobURL := ""
	if blobLen > 0 {
		blobURL = unsafe.String(blobPtr, blobLen)
	}
	contentType := ""
	if ctLen > 0 {
		contentType = unsafe.String(ctPtr, ctLen)
	}
	h.onOK(blobURL, contentType)
}

// __httpproxy_result_fail is the wasm export the supervisor calls when a
// fetch fails. status is the upstream HTTP status (0 if no response).
//
//:wasmexport __httpproxy_result_fail
func httpproxyResultFail(reqID int32, status int32, errPtr *byte, errLen int32) {
	h, ok := pendingFetches[reqID]
	if !ok {
		return
	}
	delete(pendingFetches, reqID)
	errMsg := ""
	if errLen > 0 {
		errMsg = unsafe.String(errPtr, errLen)
	}
	h.onFail(status, errMsg)
}

// === Worker-internal ===

//:wasmimport bridge httpproxy_on_message
func wasmOnMessage(cbID int32)

//:wasmimport bridge httpproxy_post
func wasmPost(ptr *byte, length int32, cap int32)

//:wasmimport bridge httpproxy_fetch
func wasmFetch(reqID int32, urlPtr *byte, urlLen int32, urlCap int32)

//:wasmimport bridge httpproxy_cancel
func wasmCancel(reqID int32)

//:wasmimport bridge httpproxy_revoke_blob
func wasmRevokeBlob(ptr *byte, length int32, cap int32)

func OnMessage(fn func(msg string)) {
	wasmOnMessage(callback.RegisterS(fn))
}

func Post(msg string) {
	wasmPost(unsafe.StringData(msg), int32(len(msg)), int32(len(msg)))
}

func Fetch(reqID int32, url string) {
	wasmFetch(reqID, unsafe.StringData(url), int32(len(url)), int32(len(url)))
}

func Cancel(reqID int32) {
	wasmCancel(reqID)
}

func RevokeBlob(url string) {
	wasmRevokeBlob(unsafe.StringData(url), int32(len(url)), int32(len(url)))
}