# Source code for pyqtgraph.parametertree.parameterTypes.file

    import os
    import re

    from ...Qt import QtCore, QtGui, QtWidgets
    from ..Parameter import Parameter
    from .str import StrParameterItem

    def _set_filepicker_kwargs(fileDlg, **kwargs):
      """Applies a dict of enum/flag kwarg opts to a file dialog"""
      NO_MATCH = object()

      for kk, vv in kwargs.items():
        # Convert string or list representations into true flags
        # 'fileMode' -> 'FileMode'
        formattedName = kk[0].upper() + kk[1:]
        # Edge case: "Options" has enum "Option"
        if formattedName == 'Options':
          enumCls = fileDlg.Option
        else:
          enumCls = getattr(fileDlg, formattedName, NO_MATCH)
        setFunc = getattr(fileDlg, f'set{formattedName}', NO_MATCH)
        if enumCls is NO_MATCH or setFunc is NO_MATCH:
          continue
        if enumCls is fileDlg.Option:
          builder = fileDlg.Option(0)
          # This is the only flag enum, all others can only take one value
          if isinstance(vv, str): vv = [vv]
          for flag in vv:
            curVal = getattr(enumCls, flag)
            builder |= curVal
          # Some Qt implementations turn into ints by this point
          outEnum = enumCls(builder)
        else:
          outEnum = getattr(enumCls, vv)
        setFunc(outEnum)

    def popupFilePicker(parent=None, windowTitle='', nameFilter='', directory=None, selectFile=None, relativeTo=None, **kwargs):
        """
        Thin wrapper around Qt file picker dialog. Used internally so all options are consistent
        among all requests for external file information

        ============== ========================================================
        **Arguments:**
        parent         Dialog parent
        windowTitle    Title of dialog window
        nameFilter     File filter as required by the Qt dialog
        directory      Where in the file system to open this dialog
        selectFile     File to preselect
        relativeTo     Parent directory that, if provided, will be removed from the prefix of all returned paths. So,
                       if '/my/text/file.txt' was selected, and `relativeTo='/my/text/'`, the return value would be
                       'file.txt'. This uses os.path.relpath under the hood, so expect that behavior.
        kwargs         Any enum value accepted by a QFileDialog and its value. Values can be a string or list of strings,
                       i.e. fileMode='AnyFile', options=['ShowDirsOnly', 'DontResolveSymlinks'], acceptMode='AcceptSave'
        ============== ========================================================

        """
        fileDlg = QtWidgets.QFileDialog(parent)
        _set_filepicker_kwargs(fileDlg, **kwargs)

        fileDlg.setModal(True)
        if directory is not None:
            fileDlg.setDirectory(directory)
        fileDlg.setNameFilter(nameFilter)
        if selectFile is not None:
            fileDlg.selectFile(selectFile)

        fileDlg.setWindowTitle(windowTitle)

        if fileDlg.exec():
            # Append filter type
            singleExtReg = r'(\.\w+)'
            # Extensions of type 'myfile.ext.is.multi.part' need to capture repeating pattern of singleExt
            suffMatch = re.search(rf'({singleExtReg}+)', fileDlg.selectedNameFilter())
            if suffMatch:
                # Strip leading '.' if it exists
                ext = suffMatch.group(1)
                if ext.startswith('.'):
                    ext = ext[1:]
                fileDlg.setDefaultSuffix(ext)
            fList = fileDlg.selectedFiles()
        else:
            fList = []
        if relativeTo is not None:
            fList = [os.path.relpath(file, relativeTo) for file in fList]
        # Make consistent to os flavor
        fList = [os.path.normpath(file) for file in fList]
        if fileDlg.fileMode() == fileDlg.FileMode.ExistingFiles:
            return fList
        elif len(fList) > 0:
            return fList[0]
        else:
            return None

    class FileParameterItem(StrParameterItem):
        def __init__(self, param, depth):
            self._value = None
            super().__init__(param, depth)

            button = QtWidgets.QPushButton('...')
            button.setFixedWidth(25)
            button.setContentsMargins(0, 0, 0, 0)
            button.clicked.connect(self._retrieveFileSelection_gui)
            self.layoutWidget.layout().insertWidget(2, button)
            self.displayLabel.resizeEvent = self._newResizeEvent
            # self.layoutWidget.layout().insertWidget(3, self.defaultBtn)

        def makeWidget(self):
            w = super().makeWidget()
            w.setValue = self.setValue
            w.value = self.value
            # Doesn't make much sense to have a 'changing' signal since filepaths should be complete before value
            # is emitted
            delattr(w, 'sigChanging')
            return w

        def _newResizeEvent(self, ev):
            ret = type(self.displayLabel).resizeEvent(self.displayLabel, ev)
            self.updateDisplayLabel()
            return ret

        def setValue(self, value):
            self._value = value
            self.widget.setText(str(value))

        def value(self):
            return self._value

        def _retrieveFileSelection_gui(self):
            curVal = self.param.value() if self.param.hasValue() else None
            if isinstance(curVal, list) and len(curVal):
                # All files should be from the same directory, in principle
                # Since no mechanism exists for preselecting multiple, the most sensible
                # thing is to select nothing in the preview dialog
                curVal = curVal[0]
                if os.path.isfile(curVal):
                    curVal = os.path.dirname(curVal)
            opts = self.param.opts.copy()
            useDir = curVal or opts.get('directory') or os.getcwd()
            startDir = os.path.abspath(useDir)
            if os.path.isfile(startDir):
                opts['selectFile'] = os.path.basename(startDir)
                startDir = os.path.dirname(startDir)
            if os.path.exists(startDir):
                opts['directory'] = startDir
            if opts.get('windowTitle') is None:
                opts['windowTitle'] = self.param.title()

            if fname := popupFilePicker(None, **opts):
                self.param.setValue(fname)

        def updateDefaultBtn(self):
            # Override since a readonly label should still allow reverting to default
            ## enable/disable default btn
            self.defaultBtn.setEnabled(
                not self.param.valueIsDefault() and self.param.opts['enabled'])

            # hide / show
            self.defaultBtn.setVisible(self.param.hasDefault())

        def updateDisplayLabel(self, value=None):
            lbl = self.displayLabel
            if value is None:
                value = self.param.value()
            value = str(value)
            font = lbl.font()
            metrics = QtGui.QFontMetricsF(font)
            value = metrics.elidedText(value, QtCore.Qt.TextElideMode.ElideLeft, lbl.width()-5)
            return super().updateDisplayLabel(value)

    class FileParameter(Parameter):
        """
        Interfaces with the myriad of file options available from a QFileDialog.

        Note that the output can either be a single file string or list of files, depending on whether
        `fileMode='ExistingFiles'` is specified.

        Note that in all cases, absolute file paths are returned unless `relativeTo` is specified as
        elaborated below.

        ============== ========================================================
        **Options:**
        parent         Dialog parent
        winTitle       Title of dialog window
        nameFilter     File filter as required by the Qt dialog
        directory      Where in the file system to open this dialog
        selectFile     File to preselect
        relativeTo     Parent directory that, if provided, will be removed from the prefix of all returned paths. So,
                       if '/my/text/file.txt' was selected, and `relativeTo='my/text/'`, the return value would be
                       'file.txt'. This uses os.path.relpath under the hood, so expect that behavior.
        kwargs         Any enum value accepted by a QFileDialog and its value. Values can be a string or list of strings,
                       i.e. fileMode='AnyFile', options=['ShowDirsOnly', 'DontResolveSymlinks']
        ============== ========================================================
        """
        itemClass = FileParameterItem

        def __init__(self, **opts):
            opts.setdefault('readonly', True)
            super().__init__(**opts)