#!/usr/bin/python3
# -*- coding: utf-8 -*-

from __future__ import print_function
import sys
import re
import fnmatch
import argparse
from abc import abstractmethod
import os
from shutil import copyfile
import subprocess

import jwutils
from jwutils.log import *

_exts_h       = set([ '.h', '.H', '.hxx', '.HXX', '.hpp'])
_exts_cpp     = set([ '.cpp', '.CPP', '.c', '.C', '.cxx', '.CXX' ])
_exts_h_cpp   = _exts_h | _exts_cpp

def _regexify(l):
    return '|'.join(x.replace('.', '\.') + '$' for x in l)

def _scantree(path, maxdepth=sys.maxsize, depth=0):
    if depth == maxdepth:
        return path
    if depth > maxdepth:
        return []
    for entry in os.scandir(path):
        if entry.is_dir(follow_symlinks=False):
            yield from _scantree(entry.path, maxdepth, depth+1)
        else:
            yield entry

# ----------------------------------------------------------------------------------- Base class

class Cmd(jwutils.Cmd):

    def __init__(self, name, help):
        self.replacements = None
        super(Cmd, self).__init__(name, help=help)

    @staticmethod
    def _replace_pattern(line, src, target, context=None):
        return line.replace(src, target)

    @staticmethod
    def _indent_pattern(data, src, target, context=None):
        indent = 30
        pattern = '='
        right_align_match = 0
        skip_lhs_pattern = None
        require_lhs_pattern = None
        skip_short = None
        min_assignments = None
        left_pad_match = 1
        if context is not None:
            if 'indent' in context:
                indent = context['indent']
            if 'pattern' in context:
                pattern = context['pattern']
            if 'right-align-match' in context:
                right_align_match = context['right-align-match']
            if 'left-pad-match' in context:
                left_pad_match = context['left-pad-match']
            if 'skip-lhs-pattern' in context:
                skip_lhs_pattern = context['skip-lhs-pattern']
            if 'require-lhs-pattern' in context:
                require_lhs_pattern = context['require-lhs-pattern']
            if 'skip-short' in context:
                skip_short = context['skip-short']
            if 'min-assignments' in context:
                min_assignments = context['min-assignments']
        r = ''
        assignments=0
        lines = data.splitlines()
        if skip_short is not None and len(lines) < skip_short:
            return data
        for line in iter(lines):
            #slog(NOTICE, "indenting pattern", pattern, "of", line)
            parts = re.split(pattern, line)
            if (
                       len(parts) < 2
                    or (skip_lhs_pattern is not None and re.match(skip_lhs_pattern, parts[0]))
                    or (require_lhs_pattern is not None and not re.match(require_lhs_pattern, parts[0]))
                ):
                r += line + '\n'
                continue
            #slog(NOTICE, "split into", parts)
            if right_align_match > 0:
                parts[1] = parts[1].rjust(right_align_match)
            lhs = parts[0].rstrip().ljust(indent)
            if len(parts) > 2:
                p2_stripped = parts[2].strip()
                if len(p2_stripped) or len(parts) > 3:
                    parts[2] = ' ' + p2_stripped
                if left_pad_match > 0:
                    pad = ''
                    #slog(NOTICE, "working off {} >{}<".format(left_pad_match, lhs[-left_pad_match:]))
                    for c in lhs[-left_pad_match:]:
                        if c != ' ':
                            pad += ' '
                    for c in parts[1]:
                        if c != ' ':
                            break
                        if len(pad):
                            pad = pad[:-1]
                    #slog(NOTICE, "  pad for {}=>{}<".format(line, pad))
                    lhs += pad
            r += lhs + ''.join(parts[1:]) + '\n'
            assignments += 1
        if min_assignments is not None and assignments < min_assignments:
            return data
        return r

    @staticmethod
    def _cpp_indent_macros(data, src, target, context=None):

        def __ctx(context, key, default):
            if key in context:
                return context[key]
            return default

        def format_line(context, indent, directive, rhs):
            if indent < 0:
                indent = 0
            spaces = __ctx(context, 'spaces', 2)
            indent_macro = __ctx(context, 'indent-macro', 0)
            indent_def = __ctx(context, 'indent-definiton', 40)
            indent_comment = __ctx(context, 'indent-comment', 70)
            rhs = rhs.strip()
            directive = directive.strip()
            r = '#' + ' ' * indent * spaces + directive
            if len(rhs) == 0:
                return r + '\n'
            r += ' '
            if indent_macro > 1:
                r = r.ljust(indent_macro - 1)
            if not directive in [ 'define' ]:
                return (r + rhs).rstrip() + '\n'
            #slog(NOTICE, "dissecting", rhs)
            m = re.match("^\s*(\w+(\([^)]*\))*)(\s+(.*))*", rhs)
            if m is None:
                raise Exception("invalid rhs", rhs)
            macro = m.group(1)
            def_and_comment = m.group(4)
            #slog(NOTICE, "macro=>{}<, def+comment=>{}<".format(macro, def_and_comment))
            r += macro
            if def_and_comment is None:
                return r.rstrip() + '\n'
            r += ' '
            if indent_def > 1:
                r = r.ljust(indent_def - 1)
            parts = re.split("(//|/\*)", def_and_comment)
            if len(parts) <= 1:
                return r + def_and_comment + '\n'
            if len(parts) == 2:
                raise Exception("Failed to dissect definition + comment", def_and_comment)
            return (r + parts[0].strip()).ljust(indent_comment) + parts[1].strip() + ' ' + ''.join(parts[2:]).strip() + '\n'

        skip_outer = True
        if context is not None:
            if 'skip-outer' in context:
                skip_outer = context['skip-outer']
        r = ''
        lnum = 0
        level = -1 if context['skip-outer'] else 0
        lines = data.splitlines()
        for line in iter(lines):
            lnum += 1
            m = re.match("^\s*#\s*(\w+)(\W*)(.*)", line)
            if m is None:
                r += line + '\n'
                continue
            directive = m.group(1)
            rhs = (m.group(2) + m.group(3)).strip()
            #slog(NOTICE, "{}: directive=>{}<, rhs=>{}<".format(level, directive, rhs))
            if directive is None or rhs is None:
                raise Exception("Syntax error in line", lnum, ":", line)
            if directive in [ "if", "ifdef", "ifndef" ]:
                r += format_line(context, level, directive, rhs)
                level += 1
                continue
            if directive in [ "else" ]:
                r += format_line(context, level - 1, directive, rhs)
                continue
            if directive in [ "endif" ]:
                level -= 1
                r += format_line(context, level, directive, rhs)
                continue
            r += format_line(context, level, directive, rhs)
        return r

    @staticmethod
    def _cleanup_spaces(data, src, target, context=None):
        lines = data.splitlines()
        last = len(lines) - 1
        r = ''
        while last >= 0 and len(lines[last].strip()) == 0:
            last -= 1
        i = 0
        while i <= last:
            r += lines[i].rstrip() + '\n'
            i += 1
        return r

    @staticmethod
    def _replace_cpp_symbol(data, src, target, context=None):
        stopc  = "^a-zA-Z0-9_"
        stopa  = "(^|[" + stopc + "])"
        stope  = "([" + stopc + "]|$)"
        f = stopa + src + stope
        t = "\\1" + target + "\\2"
        done = False
        try:
            while True:
                #slog(WARNING, "replacing", f, "by", t)
                r = re.sub(f, t, data, flags=re.MULTILINE)
                if r == data:
                    break
                data = r
        except:
            slog(ERR, "failed to replace", f, "by", t, "in", data)
            return data
        #if r != data:
        #    slog(NOTICE, "  replaced ", f, "->", t)
        #    slog(NOTICE, "  resulted in ", data, "->", r)
        return r

    def _replace_in_file(self, path, replacements, func=None, backup='rep', context=None):
        if func is None:
            func = self._replace_pattern
        tmp_ext = backup
        if tmp_ext is None:
            tmp_ext = tmp
        tmp = path + '.' + tmp_ext
        changed = False
        with open(path) as infile, open(tmp, 'w') as outfile:
            data = infile.read()
            #slog(NOTICE, "-- opened", path)
            for src, target in replacements.items():
                #slog(NOTICE, "replacing", src, "to", target)
                odata = data
                #data = data.replace(src, target)
                data = func(data, src, target, context)
                if data != odata:
                    changed = True
            outfile.write(data)
        if not changed:
            os.unlink(tmp)
            return False

        if backup is None:
            os.rename(tmp, path)
        else:
            copyfile(tmp, path)
        return True

    def _replace_in_string(self, string, replacements, func=None):
        r = ""
        if func is None:
            func = self._replace_pattern
        for line in iter(string.splitlines()):
            for src, target in replacements.items():
                line = func(line, src, target)
                r = r + line
        return r

    def _add_namespace_to_header(self, data, ns_new):
        lines = data.splitlines()
        old = None
        ns_cur = []
        for line in iter(lines):
            match = re.sub('^ *namespace[ \t]*([^ ]+)[ \t]*{.*', '\\1', line)
            if match != line:
                #ns_cur = match(blah, bl
                raise Exception("Name space addition is not yet implemented")
            classname = re.sub('^ *#[ \t]*ifndef[\t ]+([^ ]+)($|[ \t/;])', '\\1', line)

    def _fix_include_guard(self, prefix, path):
        dir, name = os.path.split(path)
        if len(name) == 0:
            return False
        trunc, ext = os.path.splitext(name)
        if ext not in _exts_h:
            return False
        tok = re.sub('([A-Z])', '_\\1', name)
        tok = re.sub('[.-]', '_', tok)
        ig = prefix + '_' + tok
        ig = re.sub('__', '_', ig)
        ig = ig.upper()
        # find first old ig

        with open(path, 'r') as f:
            odata = f.read()
        lines = odata.splitlines()
        old = None
        cand = None
        for line in iter(lines):
            if old is None:
                if cand is None:
                    m = re.match('^\s*#\s*ifndef\s+(\w+)', line)
                    if m is not None:
                        cand = m.group(1)
                else:
                    m = re.match('^\s*#\s*define\s+(\w+).*', line)
                    if m is None:
                        cand = None
                        continue
                    cand = None
                    old = m.group(1)
                    break
        if old is None:
            # TODO: add anyway at beginning and end
            raise Exception('No multiple inclusion preventer found in', path, ', not implemented')
        ndata = ''
        level = 0
        found = -1
        num=0
        for line in iter(lines):
            num += 1
            if re.match('^\s*#\s*(ifdef|ifndef|if)\s+[a-zA-Z0-9_(]', line):
                level += 1
                if found >= 0 or re.match('^\s*#\s*ifndef\s+(\w+)', line) is None:
                    ndata += line + '\n'
                    continue
                found = level
                ndata += '#ifndef ' + ig + '\n'
                continue
            elif re.match('^\s*#\s*define\s+' + old + '($|\s+)', line):
                if found != level:
                    ndata += line + '\n'
                    continue
                ndata += '#define ' + ig + '\n'
                continue
            elif re.match('^\s*#\s*endif($|\s.*)', line):
                level -= 1
                if found != level + 1:
                    ndata += line + '\n'
                    continue
                ndata += '#endif // ' + ig + '\n'
                continue
            ndata += line + '\n'
        if odata != ndata:
            slog(NOTICE, "+ fix include guards in", path)
            tmp = path + '.ig'
            with open(tmp, 'w') as f:
                f.write(ndata)
            os.rename(tmp, path)

    def add_parser(self, parsers):
        p = super(Cmd, self).add_parser(parsers)
        p.add_argument('-r', "--root", help="Point in file system from which to start search", default='.')
        p.add_argument("--name", help="Globbing pattern to select input file names", default=None)
        p.add_argument("--name-regex", help="Regular expression to select input file names", default=None)
        p.add_argument("--maxdepth", help="Maximum directory search depth", default=sys.maxsize)
        p.add_argument("--replace-patterns-from", help="File with patterns to replace, side by side, divided by '->'", default=None)
        p.add_argument("--backup", help="Backup extension", default='rep')
        p.add_argument('-g', '--git', help="Use git mv for renaming files", action='store_true', default=False)
        return p

    def _init(self, args):
        if args.replace_patterns_from is not None:
            self.replacements = dict()
            with open(args.replace_patterns_from) as infile:
                for line in infile:
                    s = re.split('->', line)
                    self.replacements[s[0]] = s[1].rstrip('\n')
            #slog(NOTICE, "replacements =", self.replacements)

    # overriding
    async def run(self, args):
        self._init(args)
        files = []
        if args.name:
            regex = fnmatch.translate(args.name)
        else:
            regex = args.name_regex
        if regex is not None:
            for entry in _scantree(args.root, args.maxdepth):
                if re.search(regex, entry.name):
                    root = os.dirname(entry.path)
                    if not root:
                        root = '.'
                    files.append((root, entry.path))
            self.process(args, files)

    @abstractmethod
    def process(self, args, files):
        pass

# ----------------------------------------------------------------------------------- commands

class CmdReplacePatterns(Cmd):

    def __init__(self):
        super(CmdReplacePatterns, self).__init__("replace-patterns", "Replace patterns in files")

    def process(self, args, files):
        for dir, name in files:
            if self.replacements is not None:
                path = dir + '/' + name
                self._replace_in_file(path, self.replacements, func=self._replace_pattern)

class CmdCleanupSpaces(Cmd):

    def __init__(self):
        super(CmdCleanupSpaces, self).__init__("cleanup-spaces", "Remove trailing empty lines")

    def add_parser(self, parsers):
        p = super(CmdCleanupSpaces, self).add_parser(parsers)
        return p

    def process(self, args, files):
        slog(NOTICE, "Cleaning up unnecessary space in", len(files), "files:")
        context = dict()
        replacements = {"blah": "blub"} # just a dummy to use _replace_in_file, TODO: obviate the need
        for dir, name in files:
            path = dir + '/' + name
            if self._replace_in_file(path, replacements, func=self._cleanup_spaces, context=context):
                slog(NOTICE, "+ purged spaces  :", path)

class CmdMkIndentEquals(Cmd):

    def __init__(self):
        super(CmdMkIndentEquals, self).__init__("mk-indent", "Indent and beautify makefiles")

    def add_parser(self, parsers):
        p = super(CmdMkIndentEquals, self).add_parser(parsers)
        p.add_argument('-e', "--equal-pos", help="Columns number of equal sign", type=int, default=40)
        p.add_argument("--skip-short", help="Don't change makefiles with less lines of code", type=int, default=6)
        p.add_argument("--min-assignments", help="Don't change makefiles with less assignment statements", type=int, default=4)
        return p

    def process(self, args, files):
        slog(NOTICE, "Beautifying", len(files), "makefiles:")
        context = dict()
        right_align_match = 2
        left_pad_match = 1
        context["indent"] = args.equal_pos - right_align_match
        context["pattern"] = "([?+:]*=|::=)"
        context["right-align-match"] = right_align_match
        context["left-pad-match"] = left_pad_match
        context["skip-lhs-pattern"] = "[^A-Za-z0-9_#    ]"
        context["require-lhs-pattern"] = "^[ #]*[A-Za-z0-9_]"
        context["skip-short"] = args.skip_short
        context["min-assignments"] = args.min_assignments
        replacements = {"blah": "blub"} # just a dummy to use _replace_in_file, TODO: obviate the need
        for dir, name in files:
            path = dir + '/' + name
            if self._replace_in_file(path, replacements, func=self._cleanup_spaces):
                slog(NOTICE, "+ purged spaces  :", path)
            if self._replace_in_file(path, replacements, func=self._indent_pattern, context=context):
                slog(NOTICE, "+ aligned equals :", path)

class CmdCppFixIncludeGuard(Cmd):

    def __init__(self):
        super(CmdCppFixIncludeGuard, self).__init__("cpp-fix-include-guard", "Standardize include guard in header files")

    def add_parser(self, parsers):
        p = super(CmdCppFixIncludeGuard, self).add_parser(parsers)
        p.add_argument('-P', '--ig-prefix', help="Prefix to include guard", default='')
        p.set_defaults(name_regex=_regexify(_exts_h))
        return p

    def process(self, args, files):
        slog(NOTICE, "Fixing include guard in", len(files), "header files:")
        for dir, name in files:
            path = dir + '/' + name
            self._fix_include_guard(args.ig_prefix, path)

class CmdCppReplaceSymbols(Cmd):

    def __init__(self):
        super(CmdCppReplaceSymbols, self).__init__("cpp-replace-symbols", "Replace C++ symbols in files")

    def add_parser(self, parsers):
        p = super(CmdCppReplaceSymbols, self).add_parser(parsers)
        p.add_argument('-F', '--rename-files', help="Rename source files, too", action='store_true', default=False)
        p.add_argument('-P', '--ig-prefix', help="Prefix to include guard", default='')
        return p

    # overriding
    async def run(self, args):
        if args.name_regex is not None:
            return super(CmdCppReplaceSymbols, self).run(args)
        self._init(args)
        files = []
        exts = _exts_h_cpp | set([ '.sh', '.py' ])
        for root, dirs, names in os.walk(args.root):
            for name in names:
                trunc, ext = os.path.splitext(name)
                if ext in exts:
                    files.append((root, name))
        self.process(args, files)

    # overriding
    def _init(self, args):
        r = super(CmdCppReplaceSymbols, self)._init(args)
        self.file_truncs = set()
        if self.replacements is not None:
            for patt in self.replacements:
                self.file_truncs.add(patt.lower())
        return r

    def process(self, args, files):
        for dir, name in files:
            path = dir + '/' + name
            if self.replacements is not None:
                self._replace_in_file(path, self.replacements, func=self._replace_cpp_symbol)
        if args.rename_files:
            for dir, name in files:
                trunc, ext = os.path.splitext(name)
                if not ext in _exts_h_cpp:
                    continue
                if not trunc.lower() in self.file_truncs:
                    continue
                for patt, repl in self.replacements.items():
                    if patt == trunc:
                        path     = dir + '/' + name
                        new_path = dir + '/' + repl + ext
                        assert(new_path != path)
                        slog(NOTICE, "renaming", path, "->", new_path)
                        if args.git:
                            subprocess.call(['git', 'mv', path, new_path])
                        else:
                            os.rename(path, new_path)
                        self._fix_include_guard(args.ig_prefix, new_path)

class CmdCppIndentMacros(Cmd):

    def __init__(self):
        super(CmdCppIndentMacros, self).__init__("cpp-indent-macros", "Indent and beautify C/C++ preprocessor macros")

    def add_parser(self, parsers):
        p = super(CmdCppIndentMacros, self).add_parser(parsers)
        p.add_argument('-w', "--spaces", help="Number of spaces per indentation level", type=int, default=2)
        p.add_argument('-s', "--skip-outer", help="Skip the outmost macro (read multiple-inclusion guards)", action='store_true', default=True)
        p.add_argument('-S', "--skip-outer-name-regex", help="Regex for file names that --skip-outer should be applied to", default=_regexify(_exts_h))
        return p

    def process(self, args, files):
        slog(NOTICE, "Beautifying", len(files), "C++ files:")
        context = dict()
        context["spaces"] = args.spaces
        replacements = {"blah": "blub"} # just a dummy to use _replace_in_file, TODO: obviate the need
        for dir, name in files:
            path = dir + '/' + name
            if self._replace_in_file(path, replacements, func=self._cleanup_spaces):
                slog(NOTICE, "+ purged spaces  :", path)
            if args.skip_outer and re.search(args.skip_outer_name_regex, path):
                context["skip-outer"] = True
            else:
                context["skip-outer"] = False
            if self._replace_in_file(path, replacements, func=self._cpp_indent_macros, context=context):
                slog(NOTICE, "+ indented C++ macros :", path)

class CmdCppAddNamespace(Cmd):

    def __init__(self):
        super(CmdCppAddNamespace, self).__init__("cpp-add-namespace", "Enclose C++ classes in namespace")

    def add_parser(self, parsers):
        p = super(CmdCppAddNamespace, self).add_parser(parsers)
        p.add_argument('-n', '--namespace', help="Namespace", default=None)
        p.add_argument('-p', '--package', help="Package", default=None)
        return p

    # overriding
    async def run(self, args):
        if args.name_regex is not None:
            return super(CmdCppAddNamespace, self).run(args)
        self._init(args)
        files = []
        exts = _exts_h_cpp | set([ '.sh', '.py' ])
        for root, dirs, names in os.walk(args.root):
            for name in names:
                trunc, ext = os.path.splitext(name)
                if ext in exts:
                    files.append((root, name))
        self.process(args, files)

    # overriding
    def _init(self, args):
        r = super(CmdCppAddNamespace, self)._init(args)
        self.file_truncs = set()
        if self.replacements is not None:
            for patt in self.replacements:
                self.file_truncs.add(patt.lower())
        return r

    def process(self, args, files):
        if args.namespace:
            for dir, name in files:
                path = dir + '/' + name
                with open(path) as infile:
                    data = odata = infile.read()
                trunc, ext = os.path.splitext(name)
                if ext in _exts_h:
                    data = self._add_namespace_to_header(data, namespace)
                elif ext in _exts_cpp:
                    data = self._add_using_namespace(data, namespace)
                #elif: Not sure what this was meant to do
                #    continue
                if data == odata:
                    continue
                tmp = path + '.' + ('rep' if args.backup is None else args.backup)
                with open(tmp, 'w') as outfile:
                    outfile.write(data)

jwutils.run_sub_commands('Process text files')