"""Core control stuff for Coverage."""

import os, socket

from coverage.annotate import AnnotateReporter
from coverage.backward import set, string_class     # pylint: disable-msg=W0622
from coverage.backward import sorted                # pylint: disable-msg=W0622
from coverage.codeunit import code_unit_factory, CodeUnit
from coverage.collector import Collector
from coverage.data import CoverageData
from coverage.files import FileLocator
from coverage.html import HtmlReporter
from coverage.misc import format_lines, CoverageException, NoSource
from coverage.summary import SummaryReporter
from coverage.xmlreport import XmlReporter

class coverage(object):
    """Programmatic access to Coverage.

    To use::
    
        from coverage import coverage
        
        cov = coverage()
        cov.start()
        #.. blah blah (run your code) blah blah ..
        cov.stop()
        cov.html_report(directory='covhtml')

    """

    def __init__(self, data_file=None, data_suffix=False, cover_pylib=False,
                auto_data=False, timid=False, branch=False):
        """Create a new coverage measurement context.
        
        `data_file` is the base name of the data file to use, defaulting to
        ".coverage".  `data_suffix` is appended to `data_file` to create the
        final file name.  If `data_suffix` is simply True, then a suffix is
        created with the machine and process identity included.
        
        `cover_pylib` is a boolean determining whether Python code installed
        with the Python interpreter is measured.  This includes the Python
        standard library and any packages installed with the interpreter.
        
        If `auto_data` is true, then any existing data file will be read when
        coverage measurement starts, and data will be saved automatically when
        measurement stops.
        
        If `timid` is true, then a slower and simpler trace function will be
        used.  This is important for some environments where manipulation of
        tracing functions breaks the faster trace function.
        
        TODO: `branch`.

        """
        from coverage import __version__
        
        self.cover_pylib = cover_pylib
        self.auto_data = auto_data
        
        self.exclude_re = ""
        self.exclude_list = []
        
        self.file_locator = FileLocator()
        
        # Timidity: for nose users, read an environment variable.  This is a
        # cheap hack, since the rest of the command line arguments aren't
        # recognized, but it solves some users' problems.
        timid = timid or ('--timid' in os.environ.get('COVERAGE_OPTIONS', ''))
        self.collector = Collector(
            self._should_trace, timid=timid, branch=branch
            )

        # Create the data file.
        if data_suffix:
            if not isinstance(data_suffix, string_class):
                # if data_suffix=True, use .machinename.pid
                data_suffix = ".%s.%s" % (socket.gethostname(), os.getpid())
        else:
            data_suffix = None

        self.data = CoverageData(
            basename=data_file, suffix=data_suffix,
            collector="coverage v%s" % __version__
            )

        # The default exclude pattern.
        self.exclude('# *pragma[: ]*[nN][oO] *[cC][oO][vV][eE][rR]')

        # The prefix for files considered "installed with the interpreter".
        if not self.cover_pylib:
            os_file = self.file_locator.canonical_filename(os.__file__)
            self.pylib_prefix = os.path.split(os_file)[0]

        here = self.file_locator.canonical_filename(__file__)
        self.cover_prefix = os.path.split(here)[0]

    def _should_trace(self, filename, frame):
        """Decide whether to trace execution in `filename`
        
        Returns a canonicalized filename if it should be traced, False if it
        should not.
        
        """
        if filename == '<string>':
            # There's no point in ever tracing string executions, we can't do
            # anything with the data later anyway.
            return False

        # Compiled Python files have two filenames: frame.f_code.co_filename is
        # the filename at the time the .pyc was compiled.  The second name
        # is __file__, which is where the .pyc was actually loaded from.  Since
        # .pyc files can be moved after compilation (for example, by being
        # installed), we look for __file__ in the frame and prefer it to the
        # co_filename value.
        dunder_file = frame.f_globals.get('__file__')
        if dunder_file:
            if not dunder_file.endswith(".py"):
                if dunder_file[-4:-1] == ".py":
                    dunder_file = dunder_file[:-1]
            filename = dunder_file

        canonical = self.file_locator.canonical_filename(filename)

        # If we aren't supposed to trace installed code, then check if this is
        # near the Python standard library and skip it if so.
        if not self.cover_pylib:
            if canonical.startswith(self.pylib_prefix):
                return False

        # We exclude the coverage code itself, since a little of it will be
        # measured otherwise.
        if canonical.startswith(self.cover_prefix):
            return False

        return canonical

    # To log what should_trace returns, change this to "if 1:"
    if 0:
        _real_should_trace = _should_trace
        def _should_trace(self, filename, frame):   # pylint: disable-msg=E0102
            """A logging decorator around the real _should_trace function."""
            ret = self._real_should_trace(filename, frame)
            print("should_trace: %r -> %r" % (filename, ret))
            return ret

    def use_cache(self, usecache):
        """Control the use of a data file (incorrectly called a cache).
        
        `usecache` is true or false, whether to read and write data on disk.
        
        """
        self.data.usefile(usecache)

    def load(self):
        """Load previously-collected coverage data from the data file."""
        self.collector.reset()
        self.data.read()
        
    def start(self):
        """Start measuring code coverage."""
        if self.auto_data:
            self.load()
            # Save coverage data when Python exits.
            import atexit
            atexit.register(self.save)
        self.collector.start()
        
    def stop(self):
        """Stop measuring code coverage."""
        self.collector.stop()
        self._harvest_data()

    def erase(self):
        """Erase previously-collected coverage data.
        
        This removes the in-memory data collected in this session as well as
        discarding the data file.
        
        """
        self.collector.reset()
        self.data.erase()

    def clear_exclude(self):
        """Clear the exclude list."""
        self.exclude_list = []
        self.exclude_re = ""

    def exclude(self, regex):
        """Exclude source lines from execution consideration.
        
        `regex` is a regular expression.  Lines matching this expression are
        not considered executable when reporting code coverage.  A list of
        regexes is maintained; this function adds a new regex to the list.
        Matching any of the regexes excludes a source line.
        
        """
        self.exclude_list.append(regex)
        self.exclude_re = "(" + ")|(".join(self.exclude_list) + ")"

    def get_exclude_list(self):
        """Return the list of excluded regex patterns."""
        return self.exclude_list

    def save(self):
        """Save the collected coverage data to the data file."""
        self._harvest_data()
        self.data.write()

    def combine(self):
        """Combine together a number of similarly-named coverage data files.
        
        All coverage data files whose name starts with `data_file` (from the
        coverage() constructor) will be read, and combined together into the
        current measurements.
        
        """
        self.data.combine_parallel_data()

    def _harvest_data(self):
        """Get the collected data and reset the collector."""
        self.data.add_line_data(self.collector.get_line_data())
        self.data.add_arc_data(self.collector.get_arc_data())
        self.collector.reset()

    # Backward compatibility with version 1.
    def analysis(self, morf):
        """Like `analysis2` but doesn't return excluded line numbers."""
        f, s, _, m, mf = self.analysis2(morf)
        return f, s, m, mf

    def analysis2(self, morf):
        """Analyze a module.
        
        `morf` is a module or a filename.  It will be analyzed to determine
        its coverage statistics.  The return value is a 5-tuple:
        
        * The filename for the module.
        * A list of line numbers of executable statements.
        * A list of line numbers of excluded statements.
        * A list of line numbers of statements not run (missing from execution).
        * A readable formatted string of the missing line numbers.

        The analysis uses the source file itself and the current measured
        coverage data.

        """
        analysis = self._analyze(morf)
        return (
            analysis.filename, analysis.statements, analysis.excluded,
            analysis.missing, analysis.missing_formatted()
            )

    def _analyze(self, it):
        """Analyze a single morf or code unit.
        
        Returns an `Analysis` object.

        """
        if not isinstance(it, CodeUnit):
            it = code_unit_factory(it, self.file_locator)[0]
        
        return Analysis(self, it)

    def report(self, morfs=None, show_missing=True, ignore_errors=False,
                file=None, omit_prefixes=None):     # pylint: disable-msg=W0622
        """Write a summary report to `file`.
        
        Each module in `morfs` is listed, with counts of statements, executed
        statements, missing statements, and a list of lines missed.
        
        """
        reporter = SummaryReporter(self, show_missing, ignore_errors)
        reporter.report(morfs, outfile=file, omit_prefixes=omit_prefixes)

    def annotate(self, morfs=None, directory=None, ignore_errors=False,
                    omit_prefixes=None):
        """Annotate a list of modules.
        
        Each module in `morfs` is annotated.  The source is written to a new
        file, named with a ",cover" suffix, with each line prefixed with a
        marker to indicate the coverage of the line.  Covered lines have ">",
        excluded lines have "-", and missing lines have "!".
        
        """
        reporter = AnnotateReporter(self, ignore_errors)
        reporter.report(
            morfs, directory=directory, omit_prefixes=omit_prefixes)

    def html_report(self, morfs=None, directory=None, ignore_errors=False,
                    omit_prefixes=None):
        """Generate an HTML report.
        
        """
        reporter = HtmlReporter(self, ignore_errors)
        reporter.report(
            morfs, directory=directory, omit_prefixes=omit_prefixes)

    def xml_report(self, morfs=None, outfile=None, ignore_errors=False,
                    omit_prefixes=None):
        """Generate an XML report of coverage results.
        
        The report is compatible with Cobertura reports.
        
        """
        if outfile:
            outfile = open(outfile, "w")
        reporter = XmlReporter(self, ignore_errors)
        reporter.report(morfs, omit_prefixes=omit_prefixes, outfile=outfile)

    def sysinfo(self):
        """Return a list of key,value pairs showing internal information."""
        
        import coverage as covmod
        import platform, re, sys

        info = [
            ('version', covmod.__version__),
            ('coverage', covmod.__file__),
            ('cover_prefix', self.cover_prefix),
            ('pylib_prefix', self.pylib_prefix),
            ('tracer', self.collector.tracer_name()),
            ('data_file', self.data.filename),
            ('python', sys.version.replace('\n', '')),
            ('platform', platform.platform()),
            ('cwd', os.getcwd()),
            ('path', sys.path),
            ('environment', [
                ("%s = %s" % (k, v)) for k, v in os.environ.items()
                    if re.search("^COV|^PY", k)
                ]),
            ]
        return info


class Analysis(object):
    """The results of analyzing a code unit."""
    
    def __init__(self, cov, code_unit):
        self.coverage = cov
        self.code_unit = code_unit
        
        from coverage.parser import CodeParser

        self.filename = self.code_unit.filename
        ext = os.path.splitext(self.filename)[1]
        source = None
        if ext == '.py':
            if not os.path.exists(self.filename):
                source = self.coverage.file_locator.get_zip_data(self.filename)
                if not source:
                    raise NoSource("No source for code: %r" % self.filename)

        self.parser = CodeParser(
            text=source, filename=self.filename,
            exclude=self.coverage.exclude_re
            )
        self.statements, self.excluded = self.parser.parse_source()

        # Identify missing statements.
        self.missing = []
        self.executed = self.coverage.data.executed_lines(self.filename)
        exec1 = self.parser.first_lines(self.executed)
        self.missing = sorted(set(self.statements) - set(exec1))

    def missing_formatted(self):
        """The missing line numbers, formatted nicely.
        
        Returns a string like "1-2, 5-11, 13-14".
        
        """
        return format_lines(self.statements, self.missing)

    def percent_covered(self):
        """Returns a single percentage value for coverage."""
        n_stm = len(self.statements)
        n_mis = len(self.missing)
        n_run = n_stm - n_mis
        if n_stm > 0:
            pc_cov = 100.0 * n_run / n_stm
        else:
            pc_cov = 100.0
        return pc_cov

    def has_arcs(self):
        """Were arcs measured in this result?"""
        return self.coverage.data.has_arcs()

    def arc_possibilities(self):
        """Returns a sorted list of the arcs in the code."""
        return self.parser.arcs()

    def arcs_executed(self):
        """Returns a sorted list of the arcs actually executed in the code."""
        executed = self.coverage.data.executed_arcs(self.filename)
        m2fl = self.parser.first_line
        executed = [(m2fl(l1), m2fl(l2)) for (l1,l2) in executed]
        return sorted(executed)

    def arcs_missing(self):
        """Returns a sorted list of the arcs in the code not executed."""
        possible = self.arc_possibilities()
        executed = self.arcs_executed()
        missing = [p for p in possible if p not in executed]
        return sorted(missing)

    def arcs_unpredicted(self):
        """Returns a sorted list of the executed arcs missing from the code."""
        possible = self.arc_possibilities()
        executed = self.arcs_executed()
        # Exclude arcs here which connect a line to itself.  They can occur
        # in executed data in some cases.  This is where they can cause
        # trouble, and here is where it's the least burden to remove them.
        unpredicted = [
            e for e in executed
                if e not in possible and e[0] != e[1]
            ]
        return sorted(unpredicted)

    def branch_lines(self):
        """Returns lines that have more than one exit."""
        exit_counts = {}
        for l1,l2 in self.arc_possibilities():
            if l1 not in exit_counts:
                exit_counts[l1] = 0
            exit_counts[l1] += 1
        
        return [l1 for l1,count in exit_counts.items() if count > 1]

    def missing_branch_arcs(self):
        """Return arcs that weren't executed from branch lines.
        
        Returns {l1:[l2a,l2b,...], ...}
        
        """
        missing = self.arcs_missing()
        branch_lines = set(self.branch_lines())
        mba = {}
        for l1, l2 in missing:
            if l1 in branch_lines:
                if l1 not in mba:
                    mba[l1] = []
                mba[l1].append(l2)
        return mba
