#
# Common.py - common database classes and functions
#
# Copyright (c) 2006-2007 The DITrack Project, www.ditrack.org.
#
# $Id: Common.py 2260 2007-10-23 11:11:01Z gli $
# $HeadURL: https://127.0.0.1/ditrack/src/tags/0.7/DITrack/DB/Common.py $
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#  * Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#  * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#

import copy
import os.path
import pprint
import re
import string
import errno
import sys

# DITrack modules
import DITrack.DB.Configuration
import DITrack.DB.Issue
import DITrack.DB.Exceptions
import DITrack.DB.LMA
import DITrack.DB.WC
from DITrack.Logging import DEBUG, get_caller
import DITrack.SVN
import DITrack.ThirdParty.Python.string
import DITrack.Util.Locking

# Root database directory property containing format version.
VERSION_PROP = "ditrack:format"

# Current database format version.
FORMAT_VERSION = "3"

# Local modifications area directory and file name
LOCAL_DT_DIR = ".ditrack"

# Lock file
LOCK_FILE = "LOCK"

def next_entity_name(names):
    """
    Generates next entity name, given the set of existing ones.

    The sequence is A, B .. Z, AA, AB, .. AZ, BA, BB, ... ZZ
    """

    if names:
        names = copy.copy(names)
        names.sort()
        prev = names[-1]
    else:
        return "A"

    assert(len(prev))

    res = ""
    carry = True
    for c in prev[::-1]:
        assert(c >= "A")
        assert(c <= "Z")

        was_carry = carry
        carry = False

        if was_carry:
            if c == "Z":
                res = "A" + res
                carry = True
            else:
                res = chr(ord(c) + 1) + res
        else:
            res = c + res

    if carry:
        res = "A" + res

    return res

#
# Classes
#

class Database:
    """
    Class representing complete database object.
    """

    def __init__(self, path, username, svn_path, mode="r", timeout=0):
        """
        XXX: rework this description, document the 'timeout' parameter.

        Opens a DITrack database at PATH. USERNAME is a username which is used
        to expand variables in filter definitions. SVN_PATH is a path to the
        Subversion command line client executable. MODE is the open mode,
        either "r" (for read-only operations) or "w" (for modifications).

        May raise the following exceptions:

        DITrack.DB.Exceptions.InvalidVersionError
            Invalid database format version.

        DITrack.DB.Exceptions.NotDatabaseError
            The directory pointed to by PATH doesn't look like a DITrack
            database.

        DITrack.DB.Exceptions.NotDirectoryError
            The PATH is not a directory.
        """

        self.lock = None
        assert (mode == "r") or (mode == "w"), mode

        # Check that it's a directory.
        if not os.path.isdir(path):
            raise DITrack.DB.Exceptions.NotDirectoryError

        # Get database version
        v = DITrack.SVN.propget(VERSION_PROP, path, svn_path)

        if not v or not len(v):
            raise DITrack.DB.Exceptions.NotDatabaseError

        # Check if this is supported version.
        if v != FORMAT_VERSION:
            raise DITrack.DB.Exceptions.InvalidVersionError

        # Creating local ditrack dir
        datadir = os.path.join(path, LOCAL_DT_DIR)
        if not os.path.exists(datadir):
            os.mkdir(datadir, 0755)

        # Lock database
        try:
            self.lock = DITrack.Util.Locking.lock(
                open(os.path.join(path, LOCAL_DT_DIR, LOCK_FILE), "w"),
                mode, timeout)
        except DITrack.Util.Locking.FileIsLockedError:
            raise DITrack.DB.Exceptions.DBIsLockedError

        # Read up the configuration.
        self.cfg = DITrack.DB.Configuration.Configuration(path, username)

        if mode != "r":
            if username not in self.cfg.users:
                raise DITrack.DB.Exceptions.InvalidUserError

        # Set up local modifications area.
        self.lma = DITrack.DB.LMA.LocalModsArea(path)

        # Working copy interface.
        self.wc = DITrack.DB.WC.WorkingCopy(path, svn_path)

    def __getitem__(self, key):
        """
        Return an issue by KEY (string id). Raises KeyError is the issue is
        neither in the WC, nor in the LMA.
        """

        # XXX: make sure the key is a string.

        DEBUG("Retrieving issue '%s' (called from %s)" % (key, get_caller()))

        try:
            issue = self.wc[key]
        except KeyError:
            issue = None

        local = None

        try:
            local = self.lma[key]
        except KeyError:
            if not issue:
                raise

        assert(issue or local)

        if issue:
            if local:
                issue.merge_local_comments(local)
                issue.update_info()
        else:
            issue = local

        return issue

    def commit_comment(self, issue_number, comment_name):
        """
        Commits comment COMMENT_NAME of issue ISSUE_NUMBER from the LMA. An
        assertion will fail if the ISSUE_NUMBER is not a firm one. Returns
        simple newly assigned comment number as a string.
        """

        DEBUG("Committing comment '%s' of issue '%s' (called from %s)" %
            (comment_name, issue_number, get_caller()))

        # XXX: use is_valid_*()
        assert issue_number.isdigit()

        lma_issue = self.lma[issue_number]
        comment = lma_issue[comment_name]

        number, changes = self.wc.new_comment(issue_number, comment)

        # XXX: if the commit has failed, we need to revert the changes back.
        self.wc.commit(changes, "i#%s: %s\n%s" %
            (issue_number, self.wc[issue_number].info["Title"],
            comment.logmsg))

        # Now, when the changes are committed, remove the comment from the LMA.
        self.lma.remove_comment(issue_number, comment_name)

        return number

    def commit_issue(self, name):
        """
        Commits issue NAME from LMA. Returns newly assigned issue number.
        """

        DEBUG("Committing issue '%s' (called from %s)" % (name, get_caller()))

        for x in name:
            assert(x in string.uppercase)

        issue = self.lma[name]
        number, changes = self.wc.new_issue(issue)

        # XXX: if the commit has failed, we need to revert the changes back.
        self.wc.commit(
            changes, 
            "i#%d added: %s\n" 
            "(assigned to %s, due in %s)" % (
                number, issue.info["Title"], issue.info["Owned-by"], 
                issue.info["Due-in"]
            )
        )

        # Now, when the changes are committed, remove the issue from the LMA.
        self.lma.remove_issue(name)

        return number

    def issue_by_id(self, id, err=True):
        """
        Fetches an issue by ID from the database, checking if 1) the identifier
        is valid; 2) the issue actually exists. If either of these checks
        fails, raises DITrack.DB.Exceptions.IssueIdSyntaxError or KeyError
        respectively. If ERR is true, prints out diagnostics before raising the
        exception.
        """

        if not self.is_valid_issue_id(id):
            if err:
                DITrack.Util.common.err("Invalid identifier: '%s'" % id)
            raise DITrack.DB.Exceptions.IssueIdSyntaxError, id

        try:
            issue = self[id]
        except KeyError:
            if err:
                DITrack.Util.common.err("No such entity: '%s'" % id)
            raise KeyError, id

        return issue

    def issues(self, from_wc=True, from_lma=True):
        """
        Return a list of tuples (ID, ISSUE) for issues present in the database.

        Issues from working copy and LMA are included as prescribed by FROM_WC
        and FROM_LMA parameters respectively. The list returned is sorted. All
        WC issues precede LMA issues.
        """

        DEBUG("from_wc=%s, from_lma=%s" % (from_wc, from_lma))

        res = {}
        if from_wc:
            for id, issue in self.wc.issues():
                res[id] = issue

        DEBUG("Firm issues: %s" % pprint.pformat(res))
        if from_lma:
            for id, issue in self.lma.issues():
                DEBUG("LMA issue entity: %s" % pprint.pformat(id))
                if self.is_valid_issue_name(id):
                    # It's a local issue, just store it.
                    res[id] = issue
                else:

                    # We are asked to return local issues only, don't bother
                    # merging comments to firm ones.
                    if not from_wc:
                        continue

                    # It's a local comment to a firm issue. We need to merge
                    # issue headers.
                    id = int(id)
                    assert id in res, pprint.pformat(id)

                    DEBUG("Merging local comments for issue '%s'" % id)
                    res[id].merge_local_comments(issue)
                    res[id].update_info()

        keys = res.keys()
        keys.sort()
        return [(k, res[k]) for k in keys]

    def is_valid_issue_number(self, id):

        issue_number_re = re.compile("^\\d+$")
        if issue_number_re.match(id):
            return int(id) != 0
        else:
            return False

    def is_valid_issue_name(self, id):
        """
        XXX: rename into valid_simple_name()
        XXX: move out of the class

        Checks if the ID passed is a syntactically valid simple entity name.

        'Simple' means 'not compound', e.g. "A" is simple, "A.B" is not.
        """

        issue_name_re = re.compile("^[A-Z]+$")
        return issue_name_re.match(id)

    def is_valid_issue_id(self, id):
        """
        Checks if the passed identifier ID is a syntactically correct
        identifier (i.e. a valid number or name).
        """

        return self.is_valid_issue_number(id) or self.is_valid_issue_name(id)

    def lma_issues(self, firm=True, local=True):
        """
        Returns a list of tuples (ID, ISSUE) for all issue entities present
        in the LMA. The FIRM and LOCAL parameters control which kind of issues
        to include into the resulting list (either FIRM or LOCAL should be
        True; or both). The returned list is sorted, firm issues always precede
        local ones.
        """

        assert (firm or local), "firm=%s, local=%s" % (firm, local)

        return self.lma.issues(firm=firm, local=local)

    def new_comment(self, issue_num, issue_before, issue_after, text, added_by,
        added_on):
        """
        Add a new comment reflecting the change in issue ISSUE_NUM from
        ISSUE_BEFORE to ISSUE_AFTER with specified TEXT to the LMA. Returns
        tuple (NAME, COMMENT). ADDED_BY and ADDED_ON are the comment's author
        and addition date respectively.

        If there is no difference and the TEXT passed is empty, raises
        DITrack.DB.Exceptions.NoDifferenceCondition.

        XXX: reflect attachments logic
        """

        delta = issue_before.diff(issue_after)
        attachment_delta = issue_before.diff_attachments(issue_after)

        if (not delta) and (not text) and (not attachment_delta):
            raise DITrack.DB.Exceptions.NoDifferenceCondition

        delta_map = {}
        for h, o, n in delta:
            delta_map[h] = (o, n)

        logmsg = []

        for (name, (old_value, new_value)) in delta_map.iteritems():
            if name == "Status":
                if new_value == "closed":
                    s = "closed"
                    if "Resolution" in delta_map:
                        s += " as %s" % delta_map["Resolution"][1]
                    logmsg.append(s)
                elif new_value == "open":
                    logmsg.append("reopened")

            elif name == "Owned-by":
                logmsg.append("reassigned to %s" % new_value)

            elif name == "Due-in":
                logmsg.append("moved to %s" % new_value)

            elif name == "Resolution":
                # Used in "Status" condition.
                continue  
            elif name == "Attachments":
                # Handled below (see attachment_delta).
                continue 

            else:
                if old_value is None:
                    old_value = ""
                if new_value is None:
                    new_value = ""
                logmsg.append("headers changed: '%s': '%s' -> '%s'" %
                        (name, old_value, new_value))



        if attachment_delta:
            for action in ("added", "removed"):
                if (action in attachment_delta) and attachment_delta[action]:
                    logmsg.append(
                        "attachment(s) %s: %s"
                        % (
                            action,
                            ", ".join(
                                map(
                                    lambda x: x.name,
                                    attachment_delta[action]
                                )
                            )
                        )
                    )

        logmsg_str = "".join ([" * %s\n" % k for k in logmsg])

        if len(text):
            logmsg_str += "\n%s\n" % text

        comment = DITrack.DB.Issue.Comment.create(text, added_on=added_on,
            added_by=added_by, delta=delta, logmsg=logmsg_str,
            attachment_delta=attachment_delta)

        name = self.lma.new_comment(issue_num, comment)

        return name, comment

    def new_issue(self, title, opened_by, opened_on, owned_by, category,
        version_reported, version_due, description):
        """
        Add a new issue to LMA of the database.

        Returns tuple (name, issue), where NAME is newly assigned name and
        ISSUE is newly created issue object.
        """

        if not owned_by:
            owned_by = self.cfg.category[category].default_owner

        issue = DITrack.DB.Issue.Issue.create(
            title=title,
            opened_by=opened_by,
            opened_on=opened_on,
            owned_by=owned_by,
            category=category,
            version_reported=version_reported,
            version_due=version_due,
            description=description
            )

        name = self.lma.new_issue(issue)

        return name, issue

    def remove_comment(self, issue_id, comment_name):
        """
        Removes local comment from the database (e.g. from the LMA).

        ValueError is raised if the ISSUE_ID is not a syntactically valid
        issue number of if COMMENT_NAME is not a syntactically valid name.

        The COMMENT_NAME parameter should refer to an existing LMA entity
        (e.g. a comment of an existing issue), otherwise KeyError is raised.
        """

        if not self.is_valid_issue_id(issue_id):
            raise ValueError

        if not self.is_valid_issue_name(comment_name):
            raise ValueError

        if not issue_id in self.lma:
            raise KeyError

        # XXX: check that KeyError will be raised if COMMENT_NAME is not
        # contained in the LMA issue
        self.lma.remove_comment(issue_id, comment_name)

    def update(self, maxage=None):
        """
        Update the working copy (sync from the repository).

        If MAXAGE is None, update the database. If the database was updated
        more than MAXAGE seconds back, update the database. Otherwise return
        taking no action.

        XXX: return values are described in WC.update()
        """
        return self.wc.update(maxage)

class Filter:
    def __init__(self, str, username=None):
        """
        Initialize the filter by parsing string expression STR. USERNAME is
        the user name to be set as the value for 'DT:USER' variable.
        """

        # Remember the way the filter was defined
        self._expression = str

        # Is it a predefined filter name?
        inplace_re = re.compile("[,=]")

        if not inplace_re.search(str):
            # This looks like a predefined filter name
            raise DITrack.DB.Exceptions.FilterIsPredefinedError(str)

        vars = dict(os.environ)
        if username is not None:
            vars["DT:USER"] = username

        # Split into subclauses.
        clauses = filter(lambda x: len(x), str.split(","))

        self.conditions = []
        condition_re = re.compile(
            "^(?P<param>[^!=]*)(?P<condition>!?=)(?P<value>.*)$"
        )

        for c in clauses:
            m = condition_re.match(c)
            if not m:
                raise DITrack.DB.Exceptions.FilterExpressionError(c)

            condition = m.groupdict()

            if len(condition) != 3:
                raise DITrack.DB.Exceptions.FilterExpressionError(c)

            # Perform substitutions.
            t = DITrack.ThirdParty.Python.string.Template(condition['value'])
            try:
                condition['value'] = t.substitute(vars)
            except KeyError, var:
               sys.stderr.write(
                   "Warning. Unknown variable in filters: %s\n" % var)
               condition['value'] = t.safe_substitute(vars)

            self.conditions.append(condition)


    def __str__(self):
        return self._expression

    def matches(self, issue):
        for c in self.conditions:
            assert len(c) == 3

            if c['param'] not in issue.info:
                return False

            if c['condition'] == "=":
                if issue.info[c['param']] != c['value']:
                    return False
            elif c['condition'] == "!=":
                if issue.info[c['param']] == c['value']:
                    return False
            else:
                raise DITrack.DB.Exceptions.NotImplemented, c['condition']

        return True