# -*- coding: utf-8 -*-

# Copyright (c) 2016 - 2021 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing tool functions for the web browser.
"""

import os
import re
import mimetypes

from PyQt5.QtCore import (
    QFile, QByteArray, QUrl, QCoreApplication, QBuffer, QIODevice
)
from PyQt5.QtGui import QPixmap


WebBrowserDataDirectory = {
    "html": os.path.join(os.path.dirname(__file__), "..", "data", "html"),
    "icons": os.path.join(os.path.dirname(__file__), "..", "data", "icons"),
    "js": os.path.join(os.path.dirname(__file__), "..", "data", "javascript"),
}


def readAllFileContents(filename):
    """
    Function to read the string contents of the given file.
    
    @param filename name of the file
    @type str
    @return contents of the file
    @rtype str
    """
    return str(readAllFileByteContents(filename), encoding="utf-8")


def readAllFileByteContents(filename):
    """
    Function to read the bytes contents of the given file.
    
    @param filename name of the file
    @type str
    @return contents of the file
    @rtype str
    """
    dataFile = QFile(filename)
    if filename and dataFile.open(QFile.ReadOnly):
        contents = dataFile.readAll()
        dataFile.close()
        return contents
    
    return QByteArray()


def containsSpace(string):
    """
    Function to check, if a string contains whitespace characters.
    
    @param string string to be checked
    @type str
    @return flag indicating the presence of at least one whitespace character
    @rtype bool
    """
    for ch in string:
        if ch.isspace():
            return True
    
    return False


def ensureUniqueFilename(name, appendFormat="({0})"):
    """
    Module function to generate an unique file name based on a pattern.
    
    @param name desired file name (string)
    @param appendFormat format pattern to be used to make the unique name
        (string)
    @return unique file name
    """
    if not os.path.exists(name):
        return name
    
    tmpFileName = name
    i = 1
    while os.path.exists(tmpFileName):
        tmpFileName = name
        index = tmpFileName.rfind(".")
        
        appendString = appendFormat.format(i)
        if index == -1:
            tmpFileName += appendString
        else:
            tmpFileName = (
                tmpFileName[:index] + appendString + tmpFileName[index:]
            )
        i += 1
    
    return tmpFileName


def getFileNameFromUrl(url):
    """
    Module function to generate a file name based on the given URL.
    
    @param url URL (QUrl)
    @return file name (string)
    """
    fileName = url.toString(QUrl.RemoveFragment | QUrl.RemoveQuery |
                            QUrl.RemoveScheme | QUrl.RemovePort)
    if fileName.find("/") != -1:
        pos = fileName.rfind("/")
        fileName = fileName[pos:]
        fileName = fileName.replace("/", "")
    
    fileName = filterCharsFromFilename(fileName)
    
    if not fileName:
        fileName = filterCharsFromFilename(url.host().replace(".", "_"))
    
    return fileName


def filterCharsFromFilename(name):
    """
    Module function to filter illegal characters.
    
    @param name name to be sanitized (string)
    @return sanitized name (string)
    """
    return (
        name
        .replace("/", "_")
        .replace("\\", "")
        .replace(":", "")
        .replace("*", "")
        .replace("?", "")
        .replace('"', "")
        .replace("<", "")
        .replace(">", "")
        .replace("|", "")
    )


def pixmapFromByteArray(data):
    """
    Module function to convert a byte array to a pixmap.
    
    @param data data for the pixmap
    @type bytes or QByteArray
    @return extracted pixmap
    @rtype QPixmap
    """
    pixmap = QPixmap()
    barray = QByteArray.fromBase64(data)
    pixmap.loadFromData(barray)
    
    return pixmap


def pixmapToByteArray(pixmap):
    """
    Module function to convert a pixmap to a byte array containing the pixmap
    as a PNG encoded as base64.
    
    @param pixmap pixmap to be converted
    @type QPixmap
    @return byte array containing the pixmap
    @rtype QByteArray
    """
    byteArray = QByteArray()
    buffer = QBuffer(byteArray)
    buffer.open(QIODevice.WriteOnly)
    if pixmap.save(buffer, "PNG"):
        return buffer.buffer().toBase64()
    
    return QByteArray()


def pixmapToDataUrl(pixmap, mimetype="image/png"):
    """
    Module function to convert a pixmap to a data: URL.
    
    @param pixmap pixmap to be converted
    @type QPixmap
    @param mimetype MIME type to be used
    @type str
    @return data: URL
    @rtype QUrl
    """
    data = bytes(pixmapToByteArray(pixmap)).decode()
    if data:
        return QUrl("data:{0};base64,{1}".format(mimetype, data))
    else:
        return QUrl()


def pixmapFileToDataUrl(pixmapFile, asString=False):
    """
    Module function to load a pixmap file and convert the pixmap to a
    data: URL.
    
    Note: If the given pixmap file path is not absolute, it is assumed to
    denote a pixmap file in the icons data directory.
    
    @param pixmapFile file name of the pixmap file
    @type str
    @param asString flag indicating a string representation is requested
    @type bool
    @return data: URL
    @rtype QUrl or str
    """
    if not os.path.isabs(pixmapFile):
        pixmapFile = os.path.join(WebBrowserDataDirectory["icons"], pixmapFile)
    
    mime = mimetypes.guess_type(pixmapFile, strict=False)[0]
    if mime is None:
        # assume PNG file
        mime = "image/png"
    url = pixmapToDataUrl(QPixmap(pixmapFile), mimetype=mime)
    
    if asString:
        return url.toString()
    else:
        return url


def getWebEngineVersions():
    """
    Module function to extract the web engine version from the default user
    agent string.
    
    @return tuple containing the Chrome version and the QtWebEngine version
    @rtype tuple of str
    """
    from PyQt5.QtWebEngineWidgets import QWebEngineProfile
    
    useragent = QWebEngineProfile.defaultProfile().httpUserAgent()
    match = re.search(r"""Chrome/([\d.]+)""", useragent)
    if match:
        chromeVersion = match.group(1)
    else:
        chromeVersion = QCoreApplication.translate(
            "WebBrowserTools", "<unknown>")
    match = re.search(r"""QtWebEngine/([\d.]+)""", useragent)
    if match:
        webengineVersion = match.group(1)
    else:
        webengineVersion = QCoreApplication.translate(
            "WebBrowserTools", "<unknown>")
    return (chromeVersion, webengineVersion)


def getHtmlPage(pageFileName):
    """
    Module function to load a HTML page.
    
    Note: If the given HTML file path is not absolute, it is assumed to
    denote a HTML file in the html data directory.
    
    @param pageFileName file name of the HTML file
    @type str
    @return HTML page
    @rtype str
    """
    if not os.path.isabs(pageFileName):
        pageFileName = os.path.join(
            WebBrowserDataDirectory["html"], pageFileName)
    
    return readAllFileContents(pageFileName)


def getJavascript(jsFileName):
    """
    Module function to load a JavaScript source file.
    
    Note: If the given JavaScript source file path is not absolute, it is
    assumed to denote a JavaScript source file in the javascript data
    directory.
    
    @param jsFileName file name of the JavaScript source file
    @type str
    @return JavaScript source
    @rtype str
    """
    if not os.path.isabs(jsFileName):
        jsFileName = os.path.join(
            WebBrowserDataDirectory["js"], jsFileName)
    
    return readAllFileContents(jsFileName)
