import QtQuick 2.15
import QtQuick.Controls 2.15
import QtQuick.Layouts 1.15
import JsonEditor 1.0
import HuskarUI.Basic 1.0

ScrollView {
    width: 600
    height: 400


    property var projectConfigStr: null // 初始化为空对象
    property var saveFunction: function(config){}
    property var errorLine: null
    property var errorPosition : null

    // JSON 处理器
    JsonProcessor {
        id: jsonProcessor
    }

    // 将 UTF-8 字节偏移量转换为 UTF-16 代码单元索引
    function utf8OffsetToUtf16Index(text, utf8Offset) {
        var utf16Index = 0;
        var utf8BytesCount = 0;

        for (var i = 0; i < text.length; i++) {
            var charCode = text.charCodeAt(i);
            var charUtf8Length = 1;

            if (charCode <= 0x7F) {
                charUtf8Length = 1;
            } else if (charCode <= 0x7FF) {
                charUtf8Length = 2;
            } else if (charCode <= 0xFFFF) {
                charUtf8Length = 3;
            } else {
                charUtf8Length = 4;
            }

            if (utf8BytesCount + charUtf8Length > utf8Offset) {
                break;
            }

            utf8BytesCount += charUtf8Length;
            utf16Index++;
        }

        return utf16Index;
    }

    function getErrorLine(text, offset) {
        var tbuf = text.slice(0,offset);
        var lines = tbuf.split('\n')
        if(lines.length > 0)return lines.length
        return -1
    }

    Rectangle{
        id:header_area
        anchors.fill: parent
        anchors.bottomMargin: 40
        color:"transparent"
        radius:8
        border.color: HusTheme.isDark ? "#23272e" : "#f0f4f7"
        border.width: 2

        ScrollView {
            id: textScrollView
            anchors.fill: parent
            clip: true
            TextArea {
                id: jsonEditor
                font.family: "Consolas"
                font.pixelSize: 14
                wrapMode: TextArea.Wrap
                placeholderText: "请输入JSON内容..."
                selectByMouse: true
                selectionColor: "#0078d4"  // 选中区域颜色（Fluent 主题蓝）
                text:projectConfigStr

                JsonHighlighter {
                    document: jsonEditor.textDocument
                }
                onTextChanged: {
                    var result = jsonProcessor.validateJson(jsonEditor.text)
                    if (result.hasError) {
                        var utf16Index = utf8OffsetToUtf16Index(jsonEditor.text, result.errorOffset);
                        errorPosition = utf16Index
                        // 计算错误行号
                        errorLine = getErrorLine(jsonEditor.text, utf16Index)
                        errorLabel.text = "❌ JSON语法错误" + `第 ${errorLine} 行出错：${result.errorMessage}`
                        errorCanvas.requestPaint()
                    } else {
                        errorLine = -1
                        errorPosition = -1
                    }
                    errorLabel.visible = (errorLine !== -1)
                }
            }

            Canvas {
                id: errorCanvas
                anchors.fill: parent
                visible: errorPosition !== -1
                z: 1
                renderTarget: Canvas.Image

                onPaint: {
                    var ctx = getContext("2d")
                    ctx.clearRect(0, 0, width, height)

                    if (errorPosition === -1) return

                    // 获取错误位置在TextArea中的坐标
                    var rect = jsonEditor.positionToRectangle(errorPosition)
                    if (!rect || rect.width === 0) return

                    // 关键步骤：映射到ScrollView的contentItem（Flickable）
                    var flickablePos = jsonEditor.mapToItem(textScrollView.contentItem, rect.x, rect.y)

                    // 计算滚动偏移后的可视坐标（减去滚动量）
                    var canvasX = flickablePos.x - textScrollView.contentItem.contentX
                    var canvasY = flickablePos.y + textScrollView.contentItem.contentY

                    // 调整标记到文本下方
                    canvasY += rect.height

                    // 绘制红色三角形（向下箭头）
                    ctx.fillStyle = "#d13438"
                    ctx.beginPath()
                    ctx.moveTo(canvasX, canvasY) // 顶点
                    ctx.lineTo(canvasX - 8, canvasY + 10) // 左下
                    ctx.lineTo(canvasX + 8, canvasY + 10) // 右下
                    ctx.closePath()
                    ctx.fill()
                }

                // 滚动时实时更新
                Connections {
                    target: textScrollView.contentItem
                    function onContentYChanged(){
                        errorCanvas.requestPaint()
                    }
                    function onContentXChanged(){
                        errorCanvas.requestPaint()
                    }
                }
            }
        }
    }

    // 按钮区域（底部固定高度）
    RowLayout {
        anchors.top:header_area.bottom
        anchors.topMargin: 6
        anchors.horizontalCenter: parent.horizontalCenter
        spacing: 15
        // 错误提示
        Text {
            id: errorLabel
            Layout.alignment: Qt.AlignHCenter
            visible: false
            color: "#d13438"
            font.bold: true
        }

        HusButton {
            text: "格式化"
            onClicked: {
                jsonEditor.text = jsonProcessor.formatJson(jsonEditor.text)
            }
        }

        HusButton {
            text: "保存"
            onClicked: saveFunction(jsonEditor.text)
        }
    }
}