#!/usr/bin/env python


__copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
__docformat__ = 'restructuredtext en'
__license__   = 'GPL v3'

import json
import os
import re
import sys
import traceback
from functools import partial

from qt.core import (
    QAbstractItemView,
    QApplication,
    QColor,
    QComboBox,
    QCursor,
    QDialog,
    QDialogButtonBox,
    QFont,
    QFontDatabase,
    QFontInfo,
    QFontMetrics,
    QIcon,
    QLineEdit,
    QPalette,
    QSize,
    QSyntaxHighlighter,
    Qt,
    QTableWidget,
    QTableWidgetItem,
    QTextCharFormat,
    QTextOption,
    QVBoxLayout,
    pyqtSignal,
)

from calibre import sanitize_file_name
from calibre.constants import config_dir
from calibre.ebooks.metadata.book.base import Metadata
from calibre.ebooks.metadata.book.formatter import SafeFormat
from calibre.gui2 import choose_files, choose_save_file, error_dialog, gprefs, pixmap_to_data, question_dialog
from calibre.gui2.dialogs.template_dialog_ui import Ui_TemplateDialog
from calibre.library.coloring import color_row_key, displayable_columns
from calibre.utils.config_base import tweaks
from calibre.utils.date import DEFAULT_DATE
from calibre.utils.formatter import PythonTemplateContext, StopException
from calibre.utils.formatter_functions import StoredObjectType, formatter_functions
from calibre.utils.icu import lower as icu_lower
from calibre.utils.icu import sort_key
from calibre.utils.localization import localize_user_manual_link, ngettext
from calibre.utils.resources import get_path as P


class ParenPosition:

    def __init__(self, block, pos, paren):
        self.block = block
        self.pos = pos
        self.paren = paren
        self.highlight = False

    def set_highlight(self, to_what):
        self.highlight = to_what


class TemplateHighlighter(QSyntaxHighlighter):
    # Code in this class is liberally borrowed from gui2.widgets.PythonHighlighter

    BN_FACTOR = 1000

    KEYWORDS_GPM = ['if', 'then', 'else', 'elif', 'fi', 'for', 'rof',
                    'separator', 'break', 'continue', 'return', 'in', 'inlist',
                    'def', 'fed', 'limit']

    KEYWORDS_PYTHON = ["and", "as", "assert", "break", "class", "continue", "def",
                       "del", "elif", "else", "except", "exec", "finally", "for", "from",
                       "global", "if", "import", "in", "is", "lambda", "not", "or",
                       "pass", "print", "raise", "return", "try", "while", "with",
                       "yield"]

    BUILTINS_PYTHON = ["abs", "all", "any", "basestring", "bool", "callable", "chr",
                       "classmethod", "cmp", "compile", "complex", "delattr", "dict",
                       "dir", "divmod", "enumerate", "eval", "execfile", "exit", "file",
                       "filter", "float", "frozenset", "getattr", "globals", "hasattr",
                       "hex", "id", "int", "isinstance", "issubclass", "iter", "len",
                       "list", "locals", "long", "map", "max", "min", "object", "oct",
                       "open", "ord", "pow", "property", "range", "reduce", "repr",
                       "reversed", "round", "set", "setattr", "slice", "sorted",
                       "staticmethod", "str", "sum", "super", "tuple", "type", "unichr",
                       "unicode", "vars", "xrange", "zip"]

    CONSTANTS_PYTHON = ["False", "True", "None", "NotImplemented", "Ellipsis"]

    def __init__(self, parent=None, builtin_functions=None):
        super().__init__(parent)
        self.initialize_formats()
        self.initialize_rules(builtin_functions, for_python=False)
        self.regenerate_paren_positions()
        self.highlighted_paren = False

    def initialize_rules(self, builtin_functions, for_python=False):
        self.for_python = for_python
        r = []

        def a(a, b):
            r.append((re.compile(a), b))

        if not for_python:
            a(r"\b[a-zA-Z]\w*\b(?!\(|\s+\()"
              r"|\$+#?[a-zA-Z]\w*",
              "identifier")
            a(r"^program:", "keymode")
            a("|".join([r"\b%s\b" % keyword for keyword in self.KEYWORDS_GPM]), "keyword")
            a("|".join([r"\b%s\b" % builtin for builtin in
                            (builtin_functions if builtin_functions else
                                                formatter_functions().get_builtins())]),
                "builtin")
            a(r"""(?<!:)'[^']*'|"[^"]*\"""", "string")
        else:
            a(r"^python:", "keymode")
            a("|".join([r"\b%s\b" % keyword for keyword in self.KEYWORDS_PYTHON]), "keyword")
            a("|".join([r"\b%s\b" % builtin for builtin in self.BUILTINS_PYTHON]), "builtin")
            a("|".join([r"\b%s\b" % constant for constant in self.CONSTANTS_PYTHON]), "constant")
            a(r"\bPyQt6\b|\bqt.core\b|\bQt?[A-Z][a-z]\w+\b", "pyqt")
            a(r"@\w+(\.\w+)?\b", "decorator")

            stringRe = r'''(["'])(?:(?!\1)[^\\]|\\.)*\1'''
            a(stringRe, "string")
            self.stringRe = re.compile(stringRe)
            self.checkTripleInStringRe = re.compile(r"""((?:"|'){3}).*?\1""")
            self.tripleSingleRe = re.compile(r"""'''(?!")""")
            self.tripleDoubleRe = re.compile(r'''"""(?!')''')
        a(
            r"\b[+-]?[0-9]+[lL]?\b"
            r"|\b[+-]?0[xX][0-9A-Fa-f]+[lL]?\b"
            r"|\b[+-]?[0-9]+(?:\.[0-9]+)?(?:[eE][+-]?[0-9]+)?\b",
            "number")

        a(r'\(', "lparen")
        a(r'\)', "rparen")
        self.Rules = tuple(r)

    def initialize_formats(self):
        font_name = gprefs.get('gpm_template_editor_font', None)
        size = gprefs['gpm_template_editor_font_size']
        if font_name is None:
            font = QFont()
            font.setFixedPitch(True)
            font.setPointSize(size)
            font_name = font.family()
        config = self.Config = {}
        config["fontfamily"] = font_name
        app_palette = QApplication.instance().palette()

        all_formats = (
            # name, color, bold, italic
            ("normal", None, False, False),
            ("keyword", app_palette.color(QPalette.ColorRole.Link).name(), True, False),
            ("builtin", app_palette.color(QPalette.ColorRole.Link).name(), False, False),
            ("constant", app_palette.color(QPalette.ColorRole.Link).name(), False, False),
            ("identifier", None, False, True),
            ("comment", "#007F00", False, True),
            ("string", "#808000", False, False),
            ("number", "#924900", False, False),
            ("decorator", "#FF8000", False, True),
            ("pyqt", None, False, False),
            ("lparen", None, True, True),
            ("rparen", None, True, True))

        for name, color, bold, italic in all_formats:
            config["%sfontcolor" % name] = color
            config["%sfontbold" % name] = bold
            config["%sfontitalic" % name] = italic
        base_format = QTextCharFormat()
        base_format.setFontFamilies([config["fontfamily"]])
        config["fontsize"] = size
        base_format.setFontPointSize(config["fontsize"])

        self.Formats = {}
        for name, color, bold, italic in all_formats:
            format_ = QTextCharFormat(base_format)
            color = config["%sfontcolor" % name]
            if color:
                format_.setForeground(QColor(color))
            if config["%sfontbold" % name]:
                format_.setFontWeight(QFont.Weight.Bold)
            format_.setFontItalic(config["%sfontitalic" % name])
            self.Formats[name] = format_

    def find_paren(self, bn, pos):
        dex = bn * self.BN_FACTOR + pos
        return self.paren_pos_map.get(dex, None)

    def replace_strings_with_dash(self, mo):
        found = mo.group(0)
        return '-' * len(found)

    def highlightBlock(self, text):
        NORMAL, TRIPLESINGLE, TRIPLEDOUBLE = range(3)

        bn = self.currentBlock().blockNumber()
        textLength = len(text)

        self.setFormat(0, textLength, self.Formats["normal"])

        if not text:
            pass
        elif text[0] == "#":
            self.setFormat(0, textLength, self.Formats["comment"])
            return

        for regex, format_ in self.Rules:
            for m in regex.finditer(text):
                i, length = m.start(), m.end() - m.start()
                if format_ in ['lparen', 'rparen']:
                    pp = self.find_paren(bn, i)
                    if pp and pp.highlight:
                        self.setFormat(i, length, self.Formats[format_])
                elif format_ == 'keymode':
                    if bn > 0 and i == 0:
                        continue
                    self.setFormat(i, length, self.Formats['keyword'])
                else:
                    self.setFormat(i, length, self.Formats[format_])

        # Deal with comments not at the beginning of the line.
        if self.for_python and '#' in text:
            # Remove any strings from the text before we check for '#'. This way
            # we avoid thinking a # inside a string starts a comment.
            t = re.sub(self.stringRe, self.replace_strings_with_dash, text)
            sharp_pos = t.find('#')
            if sharp_pos >= 0:  # Do we still have a #?
                self.setFormat(sharp_pos, len(text), self.Formats["comment"])

        self.setCurrentBlockState(NORMAL)

        if self.for_python and self.checkTripleInStringRe.search(text) is None:
            # This is fooled by triple quotes inside single quoted strings
            for m, state in (
                (self.tripleSingleRe.search(text), TRIPLESINGLE),
                (self.tripleDoubleRe.search(text), TRIPLEDOUBLE)
            ):
                i = -1 if m is None else m.start()
                if self.previousBlockState() == state:
                    if i == -1:
                        i = len(text)
                        self.setCurrentBlockState(state)
                    self.setFormat(0, i + 3, self.Formats["string"])
                elif i > -1:
                    self.setCurrentBlockState(state)
                    self.setFormat(i, len(text), self.Formats["string"])

        if self.generate_paren_positions:
            t = str(text)
            i = 0
            found_quote = False
            while i < len(t):
                c = t[i]
                if c == ':':
                    # Deal with the funky syntax of template program mode.
                    # This won't work if there are more than one template
                    # expression in the document.
                    if not found_quote and i+1 < len(t) and t[i+1] == "'":
                        i += 2
                elif c in ["'", '"']:
                    found_quote = True
                    i += 1
                    j = t[i:].find(c)
                    if j < 0:
                        i = len(t)
                    else:
                        i = i + j
                elif c in ('(', ')'):
                    pp = ParenPosition(bn, i, c)
                    self.paren_positions.append(pp)
                    self.paren_pos_map[bn*self.BN_FACTOR+i] = pp
                i += 1

    def rehighlight(self):
        QApplication.setOverrideCursor(QCursor(Qt.CursorShape.WaitCursor))
        super().rehighlight()
        QApplication.restoreOverrideCursor()

    def check_cursor_pos(self, chr_, block, pos_in_block):
        paren_pos = -1
        for i, pp in enumerate(self.paren_positions):
            pp.set_highlight(False)
            if pp.block == block and pp.pos == pos_in_block:
                paren_pos = i

        if chr_ not in ('(', ')'):
            if self.highlighted_paren:
                self.rehighlight()
                self.highlighted_paren = False
            return

        if paren_pos >= 0:
            stack = 0
            if chr_ == '(':
                list_ = self.paren_positions[paren_pos+1:]
            else:
                list_ = reversed(self.paren_positions[0:paren_pos])
            for pp in list_:
                if pp.paren == chr_:
                    stack += 1
                elif stack:
                    stack -= 1
                else:
                    pp.set_highlight(True)
                    self.paren_positions[paren_pos].set_highlight(True)
                    break
        self.highlighted_paren = True
        self.rehighlight()

    def regenerate_paren_positions(self):
        self.generate_paren_positions = True
        self.paren_positions = []
        self.paren_pos_map = {}
        self.rehighlight()
        self.generate_paren_positions = False


translate_table = str.maketrans({
    '\n': '\\n',
    '\r': '\\r',
    '\t': '\\t',
    '\\': '\\\\',
})


class TemplateDialog(QDialog, Ui_TemplateDialog):

    tester_closed = pyqtSignal(object, object)

    def setWindowTitle(self, title, dialog_number=None):
        if dialog_number is None:
            title = _('{title} (only one template dialog allowed)').format(title=title)
        else:
            title = _('{title} dialog number {number} (multiple template dialogs allowed)').format(
                    title=title, number=dialog_number)
        super().setWindowTitle(title)

    def __init__(self, parent, text, mi=None, fm=None, color_field=None,
                 icon_field_key=None, icon_rule_kind=None, doing_emblem=False,
                 text_is_placeholder=False, dialog_is_st_editor=False,
                 global_vars=None, all_functions=None, builtin_functions=None,
                 python_context_object=None, dialog_number=None):
        # If dialog_number isn't None then we want separate non-modal windows
        # that don't stay on top of the main dialog. This lets Alt-Tab work to
        # switch between them. dialog_number must be set only by the template
        # tester, not the rules dialogs etc that depend on modality.
        if dialog_number is None:
            QDialog.__init__(self, parent, flags=Qt.WindowType.Dialog)
        else:
            QDialog.__init__(self, None, flags=Qt.WindowType.Window)
            self.raise_and_focus()  # Not needed on windows but here just in case
        Ui_TemplateDialog.__init__(self)
        self.setupUi(self)
        self.setWindowIcon(self.windowIcon())

        self.dialog_number = dialog_number
        self.coloring = color_field is not None
        self.iconing = icon_field_key is not None
        self.embleming = doing_emblem
        self.dialog_is_st_editor = dialog_is_st_editor
        self.global_vars = global_vars or {}
        self.python_context_object = python_context_object or PythonTemplateContext()

        cols = []
        self.fm = fm
        if fm is not None:
            for key in sorted(displayable_columns(fm),
                              key=lambda k: sort_key(fm[k]['name'] if k != color_row_key else 0)):
                if key == color_row_key and not self.coloring:
                    continue
                from calibre.gui2.preferences.coloring import all_columns_string
                name = all_columns_string if key == color_row_key else fm[key]['name']
                if name:
                    cols.append((name, key))

        self.color_layout.setVisible(False)
        self.icon_layout.setVisible(False)

        if self.coloring:
            self.color_layout.setVisible(True)
            for n1, k1 in cols:
                self.colored_field.addItem(n1 +
                       (' (' + k1 + ')' if k1 != color_row_key else ''), k1)
            self.colored_field.setCurrentIndex(self.colored_field.findData(color_field))
        elif self.iconing or self.embleming:
            self.icon_layout.setVisible(True)
            self.icon_select_layout.setContentsMargins(0, 0, 0, 0)
            if self.embleming:
                self.icon_kind_label.setVisible(False)
                self.icon_kind.setVisible(False)
                self.icon_chooser_label.setVisible(False)
                self.icon_field.setVisible(False)

            for n1, k1 in cols:
                self.icon_field.addItem(f'{n1} ({k1})', k1)
            self.icon_file_names = []
            d = os.path.join(config_dir, 'cc_icons')
            if os.path.exists(d):
                for icon_file in os.listdir(d):
                    icon_file = icu_lower(icon_file)
                    if os.path.exists(os.path.join(d, icon_file)):
                        if icon_file.endswith('.png'):
                            self.icon_file_names.append(icon_file)
            self.icon_file_names.sort(key=sort_key)
            self.update_filename_box()

            if self.iconing:
                dex = 0
                from calibre.gui2.preferences.coloring import icon_rule_kinds
                for i,tup in enumerate(icon_rule_kinds):
                    txt,val = tup
                    self.icon_kind.addItem(txt, userData=(val))
                    if val == icon_rule_kind:
                        dex = i
                self.icon_kind.setCurrentIndex(dex)
                self.icon_field.setCurrentIndex(self.icon_field.findData(icon_field_key))

        self.setup_saved_template_editor(not dialog_is_st_editor, dialog_is_st_editor)

        self.all_functions = all_functions if all_functions else formatter_functions().get_functions()
        self.builtins = (builtin_functions if builtin_functions else
                         formatter_functions().get_builtins_and_aliases())

        # Set up the breakpoint bar
        s = gprefs.get('template_editor_break_on_print', False)
        self.go_button.setEnabled(s)
        self.remove_all_button.setEnabled(s)
        self.set_all_button.setEnabled(s)
        self.toggle_button.setEnabled(s)
        self.breakpoint_line_box.setEnabled(s)
        self.breakpoint_line_box_label.setEnabled(s)
        self.break_box.setChecked(s)
        self.break_box.stateChanged.connect(self.break_box_changed)
        self.go_button.clicked.connect(self.go_button_pressed)

        # Set up the display table
        self.table_column_widths = None
        try:
            self.table_column_widths = gprefs.get(self.geometry_string('template_editor_table_widths'), None)
        except:
            pass
        self.set_mi(mi, fm)

        self.last_text = ''
        self.highlighting_gpm = True
        self.highlighter = TemplateHighlighter(self.textbox.document(), builtin_functions=self.builtins)
        self.textbox.cursorPositionChanged.connect(self.text_cursor_changed)
        self.textbox.textChanged.connect(self.textbox_changed)
        self.set_editor_font()

        self.documentation.setReadOnly(True)
        self.source_code.setReadOnly(True)

        if text is not None:
            if text_is_placeholder:
                self.textbox.setPlaceholderText(text)
                self.textbox.clear()
                text = ''
            else:
                self.textbox.setPlainText(text)
        else:
            text = ''
        self.original_text = text

        self.buttonBox.button(QDialogButtonBox.StandardButton.Ok).setText(_('&OK'))
        self.buttonBox.button(QDialogButtonBox.StandardButton.Cancel).setText(_('&Cancel'))

        self.color_copy_button.clicked.connect(self.color_to_clipboard)
        self.filename_button.clicked.connect(self.filename_button_clicked)
        self.icon_copy_button.clicked.connect(self.icon_to_clipboard)

        try:
            with open(P('template-functions.json'), 'rb') as f:
                self.builtin_source_dict = json.load(f, encoding='utf-8')
        except:
            self.builtin_source_dict = {}

        func_names = sorted(self.all_functions)
        self.function.clear()
        self.function.addItem('')
        for f in func_names:
            self.function.addItem('{}  --  {}'.format(f,
                               self.function_type_string(f, longform=False)), f)
        self.function.setCurrentIndex(0)
        self.function.currentIndexChanged.connect(self.function_changed)
        self.rule = (None, '')

        tt = _('Template language tutorial')
        self.template_tutorial.setText(
            '<a href="{}">{}</a>'.format(
                localize_user_manual_link('https://manual.calibre-ebook.com/template_lang.html'), tt))
        tt = _('Template function reference')
        self.template_func_reference.setText(
            '<a href="{}">{}</a>'.format(
                localize_user_manual_link('https://manual.calibre-ebook.com/generated/en/template_ref.html'), tt))

        self.textbox.setFocus()
        self.set_up_font_boxes()
        self.toggle_button.clicked.connect(self.toggle_button_pressed)
        self.remove_all_button.clicked.connect(self.remove_all_button_pressed)
        self.set_all_button.clicked.connect(self.set_all_button_pressed)

        self.load_button.clicked.connect(self.load_template_from_file)
        self.save_button.clicked.connect(self.save_template)

        self.set_word_wrap(gprefs.get('gpm_template_editor_word_wrap_mode', True))
        self.textbox.setContextMenuPolicy(Qt.ContextMenuPolicy.CustomContextMenu)
        self.textbox.customContextMenuRequested.connect(self.show_context_menu)
        # Now geometry
        self.restore_geometry(gprefs, self.geometry_string('template_editor_dialog_geometry'))

    def geometry_string(self, txt):
        if self.dialog_number is None or self.dialog_number == 0:
            return txt
        return txt + '_' + str(self.dialog_number)

    def setup_saved_template_editor(self, show_buttonbox, show_doc_and_name):
        self.buttonBox.setVisible(show_buttonbox)
        self.new_doc_label.setVisible(show_doc_and_name)
        self.new_doc.setVisible(show_doc_and_name)
        self.template_name_label.setVisible(show_doc_and_name)
        self.template_name.setVisible(show_doc_and_name)

    def set_mi(self, mi, fm):
        '''
        This sets the metadata for the test result books table. It doesn't reset
        the contents of the field selectors for editing rules.
        '''
        self.fm = fm
        if mi:
            if not isinstance(mi, (tuple, list)):
                mi = (mi, )
        else:
            mi = Metadata(_('Title'), [_('Author')])
            mi.author_sort = _('Author Sort')
            mi.series = ngettext('Series', 'Series', 1)
            mi.series_index = 3
            mi.rating = 4.0
            mi.tags = [_('Tag 1'), _('Tag 2')]
            mi.languages = ['eng']
            mi.id = 1
            if self.fm is not None:
                mi.set_all_user_metadata(self.fm.custom_field_metadata())
            else:
                # No field metadata. Grab a copy from the current library so
                # that we can validate any custom column names. The values for
                # the columns will all be empty, which in some very unusual
                # cases might cause formatter errors. We can live with that.
                from calibre.gui2.ui import get_gui
                fm = get_gui().current_db.new_api.field_metadata
                mi.set_all_user_metadata(fm.custom_field_metadata())
            for col in mi.get_all_user_metadata(False):
                if fm[col]['datatype'] == 'datetime':
                    mi.set(col, DEFAULT_DATE)
                elif fm[col]['datatype'] in ('int', 'float', 'rating'):
                    mi.set(col, 2)
                elif fm[col]['datatype'] == 'bool':
                    mi.set(col, False)
                elif fm[col]['is_multiple']:
                    mi.set(col, [col])
                else:
                    mi.set(col, col, 1)
            mi = (mi, )
        self.mi = mi
        tv = self.template_value
        tv.setColumnCount(2)
        tv.setHorizontalHeaderLabels((_('Book title'), _('Template value')))
        tv.horizontalHeader().setStretchLastSection(True)
        tv.horizontalHeader().sectionResized.connect(self.table_column_resized)
        tv.setRowCount(len(mi))
        # Set the height of the table
        h = tv.rowHeight(0) * min(len(mi), 5)
        h += 2 * tv.frameWidth() + tv.horizontalHeader().height()
        tv.setMinimumHeight(h)
        tv.setMaximumHeight(h)
        # Set the size of the title column
        if self.table_column_widths:
            tv.setColumnWidth(0, self.table_column_widths[0])
        else:
            tv.setColumnWidth(0, tv.fontMetrics().averageCharWidth() * 10)
        tv.setSelectionBehavior(QAbstractItemView.SelectionBehavior.SelectRows)
        tv.setRowCount(len(mi))
        # Use our own widget to get rid of elision. setTextElideMode() doesn't work
        for r in range(0, len(mi)):
            w = QLineEdit(tv)
            w.setReadOnly(True)
            w.setText(mi[r].title)
            tv.setCellWidget(r, 0, w)
            w = QLineEdit(tv)
            w.setReadOnly(True)
            tv.setCellWidget(r, 1, w)
        self.set_waiting_message()

    def set_waiting_message(self):
        if self.break_box.isChecked():
            for i in range(len(self.mi)):
                self.template_value.cellWidget(i, 1).setText('')
            self.template_value.cellWidget(0, 1).setText(
                _("*** Breakpoints are enabled. Waiting for the 'Go' button to be pressed"))

    def show_context_menu(self, point):
        m = self.textbox.createStandardContextMenu()
        m.addSeparator()
        word_wrapping = gprefs['gpm_template_editor_word_wrap_mode']
        if word_wrapping:
            ca = m.addAction(_('Disable word wrap'))
            ca.setIcon(QIcon.ic('list_remove.png'))
        else:
            ca = m.addAction(_('Enable word wrap'))
            ca.setIcon(QIcon.ic('ok.png'))
        ca.triggered.connect(partial(self.set_word_wrap, not word_wrapping))
        m.addSeparator()
        ca = m.addAction(_('Add Python template definition text'))
        ca.triggered.connect(self.add_python_template_header_text)
        m.addSeparator()
        ca = m.addAction(_('Load template from the Template tester'))
        m.addSeparator()
        ca.triggered.connect(self.load_last_template_text)
        ca = m.addAction(_('Load template from file'))
        ca.setIcon(QIcon.ic('document_open.png'))
        ca.triggered.connect(self.load_template_from_file)
        ca = m.addAction(_('Save template to file'))
        ca.setIcon(QIcon.ic('save.png'))
        ca.triggered.connect(self.save_template)
        m.exec(self.textbox.mapToGlobal(point))

    def add_python_template_header_text(self):
        self.textbox.setPlainText('''python:
def evaluate(book, context):
\t# book is a calibre metadata object
\t# context is an instance of calibre.utils.formatter.PythonTemplateContext,
\t# which currently contains the following attributes:
\t# db: a calibre legacy database object.
\t# globals: the template global variable dictionary.
\t# arguments: is a list of arguments if the template is called by a GPM template, otherwise None.
\t# funcs: used to call Built-in/User functions and Stored GPM/Python templates.
\t# Example: context.funcs.list_re_group()

\t# your Python code goes here
\treturn 'a string'
''')

    def set_word_wrap(self, to_what):
        gprefs['gpm_template_editor_word_wrap_mode'] = to_what
        self.textbox.setWordWrapMode(QTextOption.WrapMode.WordWrap if to_what else QTextOption.WrapMode.NoWrap)

    def load_last_template_text(self):
        from calibre.customize.ui import find_plugin
        tt = find_plugin('Template Tester')
        if tt and tt.actual_plugin_:
            self.textbox.setPlainText(tt.actual_plugin_.last_template_text())
        else:
            # I don't think we can get here, but just in case ...
            self.textbox.setPlainText(_('No Template tester text is available'))

    def load_template_from_file(self):
        filename = choose_files(self, 'template_dialog_save_templates',
                _('Load template from file'),
                filters=[
                    (_('Template file'), ['txt'])
                    ], select_only_single_file=True)
        if filename:
            with open(filename[0]) as f:
                self.textbox.setPlainText(f.read())

    def save_template(self):
        filename = choose_save_file(self, 'template_dialog_save_templates',
                _('Save template to file'),
                filters=[
                    (_('Template file'), ['txt'])
                    ])
        if filename:
            with open(filename, 'w') as f:
                f.write(str(self.textbox.toPlainText()))

    def get_current_font(self):
        font_name = gprefs.get('gpm_template_editor_font', None)
        size = gprefs['gpm_template_editor_font_size']
        if font_name is None:
            font = QFont()
            font.setFixedPitch(True)
            font.setPointSize(size)
        else:
            font = QFont(font_name, pointSize=size)
        return font

    def set_editor_font(self):
        font = self.get_current_font()
        fm = QFontMetrics(font)
        chars = tweaks['template_editor_tab_stop_width']
        w = fm.averageCharWidth() * chars
        self.textbox.setTabStopDistance(w)
        self.source_code.setTabStopDistance(w)
        self.textbox.setFont(font)
        self.highlighter.initialize_formats()
        self.highlighter.rehighlight()

    def set_up_font_boxes(self):
        font = self.get_current_font()
        self.font_box.setWritingSystem(QFontDatabase.WritingSystem.Latin)
        self.font_box.setCurrentFont(font)
        self.font_box.setEditable(False)
        gprefs['gpm_template_editor_font'] = str(font.family())
        self.font_size_box.setValue(font.pointSize())
        self.font_box.currentFontChanged.connect(self.font_changed)
        self.font_size_box.valueChanged.connect(self.font_size_changed)

    def font_changed(self, font):
        fi = QFontInfo(font)
        gprefs['gpm_template_editor_font'] = str(fi.family())
        self.set_editor_font()

    def font_size_changed(self, toWhat):
        gprefs['gpm_template_editor_font_size'] = toWhat
        self.set_editor_font()

    def break_box_changed(self, new_state):
        gprefs['template_editor_break_on_print'] = new_state != 0
        self.go_button.setEnabled(new_state != 0)
        self.remove_all_button.setEnabled(new_state != 0)
        self.set_all_button.setEnabled(new_state != 0)
        self.toggle_button.setEnabled(new_state != 0)
        self.breakpoint_line_box.setEnabled(new_state != 0)
        self.breakpoint_line_box_label.setEnabled(new_state != 0)
        if new_state == 0:
            self.display_values(str(self.textbox.toPlainText()))
        else:
            self.set_waiting_message()

    def go_button_pressed(self):
        self.display_values(str(self.textbox.toPlainText()))

    def remove_all_button_pressed(self):
        self.textbox.set_clicked_line_numbers(set())

    def set_all_button_pressed(self):
        self.textbox.set_clicked_line_numbers({i for i in range(1, self.textbox.blockCount()+1)})

    def toggle_button_pressed(self):
        ln = self.breakpoint_line_box.value()
        if ln > self.textbox.blockCount():
            return
        cln = self.textbox.clicked_line_numbers
        if ln:
            if ln in self.textbox.clicked_line_numbers:
                cln.discard(ln)
            else:
                cln.add(ln)
            self.textbox.set_clicked_line_numbers(cln)

    def break_reporter(self, txt, val, locals_={}, line_number=0):
        l = self.template_value.selectionModel().selectedRows()
        mi_to_use = self.mi[0 if len(l) == 0 else l[0].row()]
        if self.break_box.isChecked():
            if line_number is None or line_number not in self.textbox.clicked_line_numbers:
                return
            self.break_reporter_dialog = BreakReporter(self, mi_to_use,
                                                       txt, val, locals_, line_number)
            if not self.break_reporter_dialog.exec():
                raise StopException()

    def filename_button_clicked(self):
        try:
            path = choose_files(self, 'choose_category_icon',
                        _('Select icon'), filters=[
                        ('Images', ['png', 'gif', 'jpg', 'jpeg'])],
                    all_files=False, select_only_single_file=True)
            if path:
                icon_path = path[0]
                icon_name = sanitize_file_name(
                             os.path.splitext(
                                   os.path.basename(icon_path))[0]+'.png')
                if icon_name not in self.icon_file_names:
                    self.icon_file_names.append(icon_name)
                    self.update_filename_box()
                    try:
                        p = QIcon(icon_path).pixmap(QSize(128, 128))
                        d = os.path.join(config_dir, 'cc_icons')
                        if not os.path.exists(os.path.join(d, icon_name)):
                            if not os.path.exists(d):
                                os.makedirs(d)
                            with open(os.path.join(d, icon_name), 'wb') as f:
                                f.write(pixmap_to_data(p, format='PNG'))
                    except:
                        traceback.print_exc()
                self.icon_files.setCurrentIndex(self.icon_files.findText(icon_name))
                self.icon_files.adjustSize()
        except:
            traceback.print_exc()
        return

    def update_filename_box(self):
        self.icon_files.clear()
        self.icon_file_names.sort(key=sort_key)
        self.icon_files.addItem('')
        self.icon_files.addItems(self.icon_file_names)
        for i,filename in enumerate(self.icon_file_names):
            icon = QIcon(os.path.join(config_dir, 'cc_icons', filename))
            self.icon_files.setItemIcon(i+1, icon)

    def color_to_clipboard(self):
        app = QApplication.instance()
        c = app.clipboard()
        c.setText(str(self.color_name.color))

    def icon_to_clipboard(self):
        app = QApplication.instance()
        c = app.clipboard()
        c.setText(str(self.icon_files.currentText()))

    @property
    def is_python(self):
        return self.textbox.toPlainText().startswith('python:')

    def textbox_changed(self):
        cur_text = str(self.textbox.toPlainText())
        if self.is_python:
            if self.highlighting_gpm is True:
                self.highlighter.initialize_rules(self.builtins, True)
                self.highlighting_gpm = False
                self.break_box.setEnabled(True)
        elif not self.highlighting_gpm:
            self.highlighter.initialize_rules(self.builtins, False)
            self.highlighting_gpm = True
            self.break_box.setEnabled(True)
        if self.last_text != cur_text:
            self.last_text = cur_text
            self.highlighter.regenerate_paren_positions()
            self.text_cursor_changed()
            if not self.break_box.isChecked():
                self.display_values(cur_text)
            else:
                self.set_waiting_message()

    def trace_lines(self, frame, event, arg):
        if event != 'line':
            return
        # Only respond to events in the "string" which is the template
        if frame.f_code.co_filename != '<string>':
            return
        # Check that there is a breakpoint at the line
        if frame.f_lineno not in self.textbox.clicked_line_numbers:
            return
        l = self.template_value.selectionModel().selectedRows()
        mi_to_use = self.mi[0 if len(l) == 0 else l[0].row()]
        self.break_reporter_dialog = PythonBreakReporter(self, mi_to_use, frame)
        if not self.break_reporter_dialog.exec():
            raise StopException()

    def trace_calls(self, frame, event, arg):
        if event != 'call':
            return
        # If this is the "string" file (the template), return the trace_lines function
        if frame.f_code.co_filename == '<string>':
            return self.trace_lines
        return None

    def display_values(self, txt):
        tv = self.template_value
        l = self.template_value.selectionModel().selectedRows()
        break_on_mi = 0 if len(l) == 0 else l[0].row()
        for r,mi in enumerate(self.mi):
            w = tv.cellWidget(r, 0)
            w.setText(mi.title)
            w.setCursorPosition(0)
            if self.break_box.isChecked() and r == break_on_mi and self.is_python:
                sys.settrace(self.trace_calls)
            else:
                sys.settrace(None)
            try:
                v = SafeFormat().safe_format(txt, mi, _('EXCEPTION:'),
                                 mi, global_vars=self.global_vars,
                                 template_functions=self.all_functions,
                                 break_reporter=self.break_reporter if r == break_on_mi else None,
                                 python_context_object=self.python_context_object)
                w = tv.cellWidget(r, 1)
                w.setText(v.translate(translate_table))
                w.setCursorPosition(0)
            finally:
                sys.settrace(None)

    def text_cursor_changed(self):
        cursor = self.textbox.textCursor()
        position = cursor.position()
        t = str(self.textbox.toPlainText())
        if position > 0 and position <= len(t):
            block_number = cursor.blockNumber()
            pos_in_block = cursor.positionInBlock() - 1
            self.highlighter.check_cursor_pos(t[position-1], block_number,
                                              pos_in_block)

    def function_type_string(self, name, longform=True):
        if self.all_functions[name].object_type is StoredObjectType.PythonFunction:
            if name in self.builtins:
                return (_('Built-in template function') if longform else
                            _('Built-in function'))
            return (_('User defined Python template function') if longform else
                            _('User function'))
        elif self.all_functions[name].object_type is StoredObjectType.StoredPythonTemplate:
            return (_('Stored user defined Python template') if longform else _('Stored template'))
        return (_('Stored user defined GPM template') if longform else _('Stored template'))

    def function_changed(self, toWhat):
        name = str(self.function.itemData(toWhat))
        self.source_code.clear()
        self.documentation.clear()
        self.func_type.clear()
        if name in self.all_functions:
            self.documentation.setPlainText(self.all_functions[name].doc)
            if name in self.builtins and name in self.builtin_source_dict:
                self.source_code.setPlainText(self.builtin_source_dict[name])
            else:
                self.source_code.setPlainText(self.all_functions[name].program_text)
            self.func_type.setText(self.function_type_string(name, longform=True))

    def table_column_resized(self, col, old, new):
        self.table_column_widths = []
        for c in range(0, self.template_value.columnCount()):
            self.table_column_widths.append(self.template_value.columnWidth(c))

    def save_geometry(self):
        gprefs[self.geometry_string('template_editor_table_widths')] = self.table_column_widths
        super().save_geometry(gprefs, self.geometry_string('template_editor_dialog_geometry'))

    def keyPressEvent(self, ev):
        if ev.key() == Qt.Key.Key_Escape:
            # Check about ESC to avoid killing the dialog by mistake
            if self.textbox.toPlainText() != self.original_text:
                r = question_dialog(self, _('Discard changes?'),
                      _('Do you really want to close this dialog, discarding any changes?'))
                if not r:
                    return
        QDialog.keyPressEvent(self, ev)

    def accept(self):
        txt = str(self.textbox.toPlainText()).rstrip()
        if (self.coloring or self.iconing or self.embleming) and not txt:
            error_dialog(self, _('No template provided'),
                _('The template box cannot be empty'), show=True)
            return
        if self.coloring:
            if self.colored_field.currentIndex() == -1:
                error_dialog(self, _('No column chosen'),
                    _('You must specify a column to be colored'), show=True)
                return
            self.rule = (str(self.colored_field.itemData(
                                self.colored_field.currentIndex()) or ''), txt)
        elif self.iconing:
            if self.icon_field.currentIndex() == -1:
                error_dialog(self, _('No column chosen'),
                    _('You must specify the column where the icons are applied'), show=True)
                return
            rt = str(self.icon_kind.itemData(self.icon_kind.currentIndex()) or '')
            self.rule = (rt,
                         str(self.icon_field.itemData(
                                self.icon_field.currentIndex()) or ''),
                         txt)
        elif self.embleming:
            self.rule = ('icon', 'title', txt)
        else:
            self.rule = ('', txt)
        self.save_geometry()
        QDialog.accept(self)
        if self.dialog_number is not None:
            self.tester_closed.emit(txt, self.dialog_number)

    def reject(self):
        self.save_geometry()
        QDialog.reject(self)
        if self.dialog_is_st_editor:
            parent = self.parent()
            while True:
                if hasattr(parent, 'reject'):
                    parent.reject()
                    break
                parent = parent.parent()
                if parent is None:
                    break
        if self.dialog_number is not None:
            self.tester_closed.emit(None, self.dialog_number)


class BreakReporterItem(QTableWidgetItem):

    def __init__(self, txt):
        super().__init__(txt.translate(translate_table) if txt else txt)
        self.setFlags(self.flags() & ~(Qt.ItemFlag.ItemIsEditable))


class BreakReporterBase(QDialog):

    def setup_ui(self, mi, line_number, locals_, leading_rows):
        self.mi = mi
        self.leading_rows = leading_rows
        self.setModal(True)
        l = QVBoxLayout(self)
        t = self.table = QTableWidget(self)
        t.setSelectionMode(QAbstractItemView.SelectionMode.SingleSelection)
        t.setColumnCount(2)
        t.setHorizontalHeaderLabels((_('Name'), _('Value')))
        t.setRowCount(leading_rows)
        l.addWidget(t)

        self.table_column_widths = None
        try:
            self.table_column_widths = \
                        gprefs.get('template_editor_break_table_widths', None)
            t.setColumnWidth(0, self.table_column_widths[0])
        except:
            t.setColumnWidth(0, t.fontMetrics().averageCharWidth() * 20)
        t.horizontalHeader().sectionResized.connect(self.table_column_resized)
        t.horizontalHeader().setStretchLastSection(True)

        bb = QDialogButtonBox()
        b = bb.addButton(_('&Continue'), QDialogButtonBox.ButtonRole.AcceptRole)
        b.setIcon(QIcon.ic('sync-right.png'))
        b.setToolTip(_('Continue running the template'))
        b.setDefault(True)
        l.addWidget(bb)
        b = bb.addButton(_('&Stop'), QDialogButtonBox.ButtonRole.RejectRole)
        b.setIcon(QIcon.ic('list_remove.png'))
        b.setToolTip(_('Stop running the template'))
        l.addWidget(bb)
        bb.accepted.connect(self.accept)
        bb.rejected.connect(self.reject)
        self.setLayout(l)
        self.setWindowTitle(_('Break: line {0}, book {1}').format(line_number, self.mi.title))

        self.mi_combo = QComboBox()
        t.setCellWidget(leading_rows-1, 0, self.mi_combo)
        self.mi_combo.addItems(self.get_field_keys())
        self.mi_combo.setToolTip('Choose a book metadata field to display')
        self.mi_combo.currentTextChanged.connect(self.get_field_value)
        self.mi_combo.setCurrentIndex(self.mi_combo.findText('title'))
        self.restore_geometry(gprefs, 'template_editor_break_geometry')
        self.setup_locals(locals_)

    def setup_locals(self, locals_):
        raise NotImplementedError

    def add_local_line(self, locals, row, key):
        itm = BreakReporterItem(key)
        itm.setToolTip(_('A variable in the template'))
        self.table.setItem(row, 0, itm)
        itm = BreakReporterItem(repr(locals[key]))
        itm.setToolTip(_('The value of the variable'))
        self.table.setItem(row, 1, itm)

    def get_field_value(self, field):
        val = self.displayable_field_value(self.mi, field)
        self.table.setItem(self.leading_rows-1, 1, BreakReporterItem(val))

    def displayable_field_value(self, mi, field):
        raise NotImplementedError

    def table_column_resized(self, col, old, new):
        self.table_column_widths = []
        for c in range(0, self.table.columnCount()):
            self.table_column_widths.append(self.table.columnWidth(c))

    def get_field_keys(self):
        from calibre.gui2.ui import get_gui
        keys = set(get_gui().current_db.new_api.field_metadata.displayable_field_keys())
        keys.discard('sort')
        keys.discard('timestamp')
        keys.add('title_sort')
        keys.add('date')
        return sorted(keys)

    def save_geometry(self):
        super().save_geometry(gprefs, 'template_editor_break_geometry')
        gprefs['template_editor_break_table_widths'] = self.table_column_widths

    def reject(self):
        self.save_geometry()
        QDialog.reject(self)

    def accept(self):
        self.save_geometry()
        QDialog.accept(self)


class BreakReporter(BreakReporterBase):

    def __init__(self, parent, mi, op_label, op_value, locals_, line_number):
        super().__init__(parent)
        self.setup_ui(mi, line_number, locals_, leading_rows=2)
        self.table.setItem(0, 0, BreakReporterItem(op_label))
        self.table.item(0,0).setToolTip(_('The name of the template language operation'))
        self.table.setItem(0, 1, BreakReporterItem(op_value))

    def setup_locals(self, locals):
        local_names = sorted(locals.keys())
        rows = len(local_names)
        self.table.setRowCount(rows+2)
        for i,k in enumerate(local_names, start=2):
            self.add_local_line(locals, i, k)

    def displayable_field_value(self, mi, field):
        return self.mi.format_field('timestamp' if field == 'date' else field)[1]


class PythonBreakReporter(BreakReporterBase):

    def __init__(self, parent, mi, frame):
        super().__init__(parent)
        self.frame = frame
        line_number = frame.f_lineno
        locals = frame.f_locals
        self.setup_ui(mi, line_number, locals, leading_rows=1)

    def setup_locals(self, locals):
        locals = self.frame.f_locals
        local_names = sorted(k for k in locals.keys() if k not in ('book', 'context'))
        rows = len(local_names)
        self.table.setRowCount(rows+1)

        for i,k in enumerate(local_names, start=1):
            if k in ('book', 'context'):
                continue
            self.add_local_line(locals, i, k)

    def displayable_field_value(self, mi, field):
        return repr(self.mi.get('timestamp' if field == 'date' else field))


class EmbeddedTemplateDialog(TemplateDialog):

    def __init__(self, parent):
        TemplateDialog.__init__(self, parent, _('A General Program Mode Template'), text_is_placeholder=True,
                                dialog_is_st_editor=True)
        self.setParent(parent)
        self.setWindowFlags(Qt.WindowType.Widget)


if __name__ == '__main__':
    from calibre.gui2 import Application
    app = Application([])
    from calibre.ebooks.metadata.book.base import field_metadata
    d = TemplateDialog(None, '{title}', fm=field_metadata)
    d.exec()
    del app
