#!/usr/bin/env python
"""Copyright Joel Schaerer 2008-2010
This file is part of autojump

autojump is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

autojump is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with autojump.  If not, see <http://www.gnu.org/licenses/>.

Autojump is a small tool that maintains a database of your most
used directories, and finds the best match to help you jump to
frequently used places."""

from __future__ import division, print_function

try: # fix to get optimised pickle in python < 3
    import cPickle as pickle
except ImportError:
    import pickle

import getopt
from sys import argv, stderr, version_info, exit
from tempfile import NamedTemporaryFile
from operator import itemgetter
import os
MAX_KEYWEIGHT = 1000
MAX_STORED_PATHS = 600
COMPLETION_SEPARATOR = '__'
CONFIG_DIR = os.environ.get("AUTOJUMP_DATA_DIR", os.path.expanduser("~"))

def uniqadd(collection, key):
    """Adds a key to a list only if it is not already present"""
    if key not in collection:
        collection.append(key)

def dicadd(dic, key, increment=1):
    """Increment a value in a dic, set it to 0
    if is is not already present"""
    dic[key] = dic.get(key, 0.)+increment

def save(path_dict, dic_file):
    """Save the database in an atomic way, and preserve
       a backup file."""
    # If the dic_file exists, check that it belongs to us
    # Otherwise, fail quietly
    if (not os.path.exists(dic_file)) or os.getuid() == os.stat(dic_file)[4]:
        temp = NamedTemporaryFile(dir=CONFIG_DIR, delete=False)
        pickle.dump(path_dict, temp, 2)
        temp.flush()
        os.fsync(temp)
        temp.close()
        #cf. http://thunk.org/tytso/blog/2009/03/15/dont-fear-the-fsync/
        os.rename(temp.name, dic_file) 
        try: #backup file
            import time 
            if (not os.path.exists(dic_file+".bak") or
                    time.time()-os.path.getmtime(dic_file+".bak")>86400):
                import shutil
                shutil.copy(dic_file, dic_file+".bak")
        except OSError as ex:
            print("Error while creating backup autojump file. (%s)" %
                    ex, file=stderr)

def forget(path_dict, dic_file):
    """Gradually forget about directories. Only call
    from the actual jump since it can take time"""
    keyweight = sum(path_dict.values()) 
    if keyweight > MAX_KEYWEIGHT: 
        for k in path_dict.keys():
            path_dict[k] *= 0.9 * MAX_KEYWEIGHT / keyweight
        save(path_dict, dic_file)

def clean_dict(sorted_dirs, path_dict):
    """Limits the sized of the path_dict to MAX_STORED_PATHS. 
    Returns True if keys were deleted"""
    if len(sorted_dirs) > MAX_STORED_PATHS:
        #remove 25 more than needed, to avoid doing it every time
        for path, dummy in sorted_dirs[MAX_STORED_PATHS-25:]:
            del path_dict[path]
        return True
    else: return False

def match(path, pattern, ignore_case=False, only_end=False):
    """Check whether a path matches a particular pattern"""
    try:
        if os.path.realpath(os.curdir) == path :
            return False
    #Sometimes the current path doesn't exist anymore.
    #In that case, jump if possible.
    except OSError:
        pass
    if only_end:
        match_string = "/".join(path.split('/')[-1-pattern.count('/'):])
    else:
        match_string = path
    if ignore_case:
        does_match = (match_string.lower().find(pattern.lower()) != -1)
    else:
        does_match = (match_string.find(pattern) != -1)
    #return True if there is a match and the path exists 
    #(useful in the case of external drives, for example)
    return does_match and os.path.exists(path) 

def find_matches(dirs, patterns, result_list, ignore_case, max_matches):
    """Find max_matches paths that match the pattern, 
    and add them to the result_list"""
    for path, count in dirs:
        if len(result_list) >= max_matches :
            break
        #For the last pattern, only match the end of the pattern
        if all(match(path, p, ignore_case,
            only_end=(n == len(patterns)-1)) for n, p in enumerate(patterns)):
            uniqadd(result_list, path)

def open_dic(dic_file, error_recovery=False):
    """Try hard to open the database file, recovering
       from backup if needed. """
    try:
        aj_file = open(dic_file, 'rb')
        if version_info[0] > 2:
            #encoding is only specified for python2.x compatibility
            path_dict = pickle.load(aj_file, encoding="utf-8")
        else:
            path_dict = pickle.load(aj_file)
        aj_file.close()
        return path_dict
    except (IOError, EOFError, pickle.UnpicklingError):
        if not error_recovery and os.path.exists(dic_file+".bak"):
            print('Problem with autojump database,\
                    trying to recover from backup...', file=stderr)
            import shutil
            shutil.copy(dic_file+".bak", dic_file)
            return open_dic(dic_file, True)
        else: return {} #if everything fails, return an empty file

def get_dic_file():
    if CONFIG_DIR == os.path.expanduser("~"):
        dic_file = CONFIG_DIR+"/.autojump_py"
    else:
        dic_file = CONFIG_DIR+"/autojump_py"
    return dic_file

def shell_utility():
    """Run this when autojump is called as a shell utility"""
    try:
        optlist, args = getopt.getopt(argv[1:], 'a',
                ['stat', 'import', 'completion', 'bash']) 
    except getopt.GetoptError as ex:
        print("Unknown command line argument: %s" % ex)
        exit(1)

    dic_file = get_dic_file()
    path_dict = open_dic(dic_file)
    if ('-a', '') in optlist:
        # The home dir can be reached quickly by "cd"
        # and may interfere with other directories
        if(args[-1] != os.path.expanduser("~")): 
            dicadd(path_dict, args[-1])
            save(path_dict, dic_file)
    elif ('--stat', '') in optlist:
        paths = list(path_dict.items())
        paths.sort(key=itemgetter(1))
        for path, count in paths[-100:]:
            print("%.1f:\t%s" % (count, path))
        print("Total key weight: %d. Number of stored paths: %d" %
                (sum(path_dict.values()), len(paths)))
    else:
        import re
        completion = False
        #userchoice is i if the pattern is __pattern__i, otherwise -1
        userchoice = -1 
        results = []
        if ('--completion', '') in optlist:
            completion = True
        else:
            forget(path_dict, dic_file) #gradually forget about old directories
        if not args: patterns = [""]
        else: patterns = args

        # If the last pattern contains a full path, jump there
        # The regexp is because we need to support stuff like
        # "j wo jo__3__/home/joel/workspace/joel" for zsh
        last_pattern_path = re.sub("(.*)"+COMPLETION_SEPARATOR, "", patterns[-1])
        if (len(last_pattern_path)>0 and
              last_pattern_path[0] == "/" and
              os.path.exists(last_pattern_path)):
            if not completion: print(last_pattern_path)
        else:
            #check for ongoing completion, and act accordingly
            endmatch = re.search(COMPLETION_SEPARATOR+"([0-9]+)", patterns[-1])
            if endmatch:  #user has selected a completion
                userchoice = int(endmatch.group(1))
                patterns[-1] = re.sub(COMPLETION_SEPARATOR+"[0-9]+.*",
                        "", patterns[-1])
            else: #user hasn't selected a completion, display the same choices again
                endmatch = re.match("(.*)"+COMPLETION_SEPARATOR, patterns[-1])
                if endmatch: patterns[-1] = endmatch.group(1)

            dirs = list(path_dict.items())
            dirs.sort(key=itemgetter(1), reverse=True)
            if completion or userchoice != -1:
                max_matches = 9
            else:
                max_matches = 1
            find_matches(dirs, patterns, results, False, max_matches)
            # If not found, try ignoring case.
            # On completion always show all results
            if completion or not results: 
                find_matches(dirs, patterns, results,
                        ignore_case=True, max_matches=max_matches) 
            # Keep the database to a reasonable size
            if not completion and clean_dict(dirs, path_dict):
                save(path_dict, dic_file)

            if completion and ('--bash', '') in optlist: quotes = '"'
            else: quotes = ""

            if userchoice != -1:
                if len(results) > userchoice-1 : 
                    print(quotes+results[userchoice-1]+quotes)
            elif len(results) > 1 and completion:
                print("\n".join(("%s%s%d%s%s" % (patterns[-1],
                    COMPLETION_SEPARATOR, n+1, COMPLETION_SEPARATOR, r)
                    for n, r in enumerate(results[:8]))))
            elif results: print(quotes+results[0]+quotes)
            else:
                return False
            return True


if __name__ == "__main__":
    success=shell_utility()
    if not success: exit(1)