rui/wasmBridge.go

//go:build wasm

package rui

import (
	"fmt"
	"strconv"
	"strings"
	"syscall/js"
)

type wasmBridge struct {
	answer     map[int]chan DataObject
	answerID   int
	canvas     js.Value
	closeEvent chan DataObject
}

func createWasmBridge(close chan DataObject) bridge {
	bridge := new(wasmBridge)
	bridge.answerID = 1
	bridge.answer = make(map[int]chan DataObject)
	bridge.closeEvent = close

	return bridge
}

func (bridge *wasmBridge) startUpdateScript(htmlID string) bool {
	return false
}

func (bridge *wasmBridge) finishUpdateScript(htmlID string) {
}

func (bridge *wasmBridge) printFuncToLog(funcName string, args ...any) {
	if ProtocolInDebugLog {
		text := funcName + "("
		for i, arg := range args {
			if i > 0 {
				text += fmt.Sprintf(", `%v`", arg)
			} else {
				text += fmt.Sprintf("`%v`", arg)
			}
		}
		DebugLog(text + ")")
	}
}

func (bridge *wasmBridge) callFunc(funcName string, args ...any) bool {
	bridge.printFuncToLog(funcName, args...)

	js.Global().Call(funcName, args...)
	return true
}

func (bridge *wasmBridge) updateInnerHTML(htmlID, html string) {
	if ProtocolInDebugLog {
		DebugLog(fmt.Sprintf("%s.innerHTML = '%s'", htmlID, html))
	}

	element := js.Global().Get("document").Call("getElementById", htmlID)
	if !element.IsUndefined() && !element.IsNull() {
		element.Set("innerHTML", html)
		js.Global().Call("scanElementsSize")
	}
}

func (bridge *wasmBridge) appendToInnerHTML(htmlID, html string) {
	if ProtocolInDebugLog {
		DebugLog(fmt.Sprintf("%s.innerHTML += '%s'", htmlID, html))
	}

	element := js.Global().Get("document").Call("getElementById", htmlID)
	if !element.IsUndefined() && !element.IsNull() {
		oldHtml := element.Get("innerHTML").String()
		element.Set("innerHTML", oldHtml+html)
		js.Global().Call("scanElementsSize")
	}
}

func (bridge *wasmBridge) updateCSSProperty(htmlID, property, value string) {
	if ProtocolInDebugLog {
		DebugLog(fmt.Sprintf("%s.style[%s] = '%s'", htmlID, property, value))
	}

	element := js.Global().Get("document").Call("getElementById", htmlID)
	if !element.IsUndefined() && !element.IsNull() {
		element.Get("style").Set(property, value)
		js.Global().Call("scanElementsSize")
	}
}

func (bridge *wasmBridge) updateProperty(htmlID, property string, value any) {
	bridge.callFunc("updateProperty", htmlID, property, value)
}

func (bridge *wasmBridge) removeProperty(htmlID, property string) {
	bridge.callFunc("removeProperty", htmlID, property)
}

func (bridge *wasmBridge) close() {
	bridge.closeEvent <- NewDataObject("close")
}

func (bridge *wasmBridge) writeMessage(script string) bool {
	if ProtocolInDebugLog {
		DebugLog("Run script:")
		DebugLog(script)
	}

	window := js.Global().Get("window")
	window.Call("execScript", script)

	return true
}

func (bridge *wasmBridge) prepareCSS(css string) string {
	css = strings.ReplaceAll(css, `\t`, "\t")
	css = strings.ReplaceAll(css, `\n`, "\n")
	css = strings.ReplaceAll(css, `\'`, "'")
	css = strings.ReplaceAll(css, `\"`, "\"")
	css = strings.ReplaceAll(css, `\\`, "\\")
	return css
}

func (bridge *wasmBridge) appendAnimationCSS(css string) {
	styles := js.Global().Get("document").Call("getElementById", "ruiAnimations")
	content := styles.Get("textContent").String()
	styles.Set("textContent", content+"\n"+bridge.prepareCSS(css))
}

func (bridge *wasmBridge) setAnimationCSS(css string) {
	styles := js.Global().Get("document").Call("getElementById", "ruiAnimations")
	styles.Set("textContent", bridge.prepareCSS(css))
}

func (bridge *wasmBridge) canvasStart(htmlID string) {
	if ProtocolInDebugLog {
		DebugLog("const ctx = document.getElementById('" + htmlID + "'elementId').getContext('2d');\nctx.save();")
	}

	bridge.canvas = js.Global().Call("getCanvasContext", htmlID)
	if !bridge.canvas.IsNull() {
		bridge.canvas.Call("save")
	}
}

func (bridge *wasmBridge) callCanvasFunc(funcName string, args ...any) {
	if !bridge.canvas.IsNull() {
		for i, arg := range args {
			if array, ok := arg.([]float64); ok {
				arr := make([]any, len(array))
				for k, x := range array {
					arr[k] = x
				}
				args[i] = js.ValueOf(arr)
			}
		}

		bridge.printFuncToLog("ctx."+funcName, args...)
		bridge.canvas.Call(funcName, args...)
	}
}

func (bridge *wasmBridge) callCanvasVarFunc(v any, funcName string, args ...any) {
	if jsVar, ok := v.(js.Value); ok && !jsVar.IsNull() {
		bridge.printFuncToLog(jsVar.String()+"."+funcName, args...)
		jsVar.Call(funcName, args...)
	}
}

func (bridge *wasmBridge) callCanvasImageFunc(url string, property string, funcName string, args ...any) {
	image := js.Global().Get("images").Call("get", url)
	if !image.IsUndefined() && !image.IsNull() && !bridge.canvas.IsNull() {
		args = append([]any{image}, args...)
		result := bridge.canvas.Call(funcName, args...)
		if property != "" {
			bridge.printFuncToLog("ctx."+property+" = ctx."+funcName, args...)
			bridge.canvas.Set(property, result)
		} else {
			bridge.printFuncToLog("ctx."+funcName, args...)
		}
	}
}

func (bridge *wasmBridge) createCanvasVar(funcName string, args ...any) any {
	if bridge.canvas.IsNull() {
		return bridge.canvas
	}

	result := bridge.canvas.Call(funcName, args...)
	bridge.printFuncToLog("var "+result.String()+" = ctx."+funcName, args...)
	return result
}

func (bridge *wasmBridge) updateCanvasProperty(property string, value any) {
	if !bridge.canvas.IsNull() {
		if ProtocolInDebugLog {
			DebugLog(fmt.Sprintf("ctx.%s = '%v'", property, value))
		}

		bridge.canvas.Set(property, value)
	}
}

func (bridge *wasmBridge) canvasFinish() {
	if !bridge.canvas.IsNull() {
		DebugLog("ctx.restore()")
		bridge.canvas.Call("restore")
	}
}

func (bridge *wasmBridge) canvasTextMetrics(htmlID, font, text string) TextMetrics {

	result := TextMetrics{}

	canvas := js.Global().Get("document").Call("getElementById", htmlID)
	if !canvas.IsUndefined() && !canvas.IsNull() {
		context := canvas.Call("getContext", "2d")
		if !context.IsUndefined() && !context.IsNull() {
			context.Call("save")
			context.Set("font", font)
			context.Set("textBaseline", "alphabetic")
			context.Set("textAlign", "start")

			metrics := context.Call("measureText", text)
			if !metrics.IsUndefined() && !metrics.IsNull() {
				metricsValue := func(name string) float64 {
					value := metrics.Get(name)
					if !value.IsUndefined() && !value.IsNull() && value.Type() == js.TypeNumber {
						return value.Float()
					}
					return 0
				}

				result.Width = metricsValue("width")
				result.Ascent = metricsValue("actualBoundingBoxAscent")
				result.Descent = metricsValue("actualBoundingBoxDescent")
				result.Left = metricsValue("actualBoundingBoxLeft")
				result.Right = metricsValue("actualBoundingBoxRight")
			}
			context.Call("restore")
		}
	}

	return result
}

func (bridge *wasmBridge) htmlPropertyValue(htmlID, name string) string {
	element := js.Global().Get("document").Call("getElementById", htmlID)
	if !element.IsUndefined() && !element.IsNull() {
		return element.Get(name).String()
	}

	return ""
}

func (bridge *wasmBridge) answerReceived(answer DataObject) {
	if text, ok := answer.PropertyValue("answerID"); ok {
		if id, err := strconv.Atoi(text); err == nil {
			if chanel, ok := bridge.answer[id]; ok {
				chanel <- answer
				delete(bridge.answer, id)
			} else {
				ErrorLog("Bad answerID = " + text + " (chan not found)")
			}
		} else {
			ErrorLog("Invalid answerID = " + text)
		}
	} else {
		ErrorLog("answerID not found")
	}
}

func (bridge *wasmBridge) remoteAddr() string {
	return "localhost"
}

func (bridge *wasmBridge) sendResponse() {
}