#!/usr/bin/env python3

"""Analyze the test outcomes from a full CI run.

This script can also run on outcomes from a partial run, but the results are
less likely to be useful.
"""

import argparse
import re
import sys
import traceback

import check_test_cases

class Results:
    """Process analysis results."""

    def __init__(self):
        self.error_count = 0
        self.warning_count = 0

    @staticmethod
    def log(fmt, *args, **kwargs):
        sys.stderr.write((fmt + '\n').format(*args, **kwargs))

    def error(self, fmt, *args, **kwargs):
        self.log('Error: ' + fmt, *args, **kwargs)
        self.error_count += 1

    def warning(self, fmt, *args, **kwargs):
        self.log('Warning: ' + fmt, *args, **kwargs)
        self.warning_count += 1

class TestCaseOutcomes:
    """The outcomes of one test case across many configurations."""
    # pylint: disable=too-few-public-methods

    def __init__(self):
        # Collect a list of witnesses of the test case succeeding or failing.
        # Currently we don't do anything with witnesses except count them.
        # The format of a witness is determined by the read_outcome_file
        # function; it's the platform and configuration joined by ';'.
        self.successes = []
        self.failures = []

    def hits(self):
        """Return the number of times a test case has been run.

        This includes passes and failures, but not skips.
        """
        return len(self.successes) + len(self.failures)

class TestDescriptions(check_test_cases.TestDescriptionExplorer):
    """Collect the available test cases."""

    def __init__(self):
        super().__init__()
        self.descriptions = set()

    def process_test_case(self, _per_file_state,
                          file_name, _line_number, description):
        """Record an available test case."""
        base_name = re.sub(r'\.[^.]*$', '', re.sub(r'.*/', '', file_name))
        key = ';'.join([base_name, description.decode('utf-8')])
        self.descriptions.add(key)

def collect_available_test_cases():
    """Collect the available test cases."""
    explorer = TestDescriptions()
    explorer.walk_all()
    return sorted(explorer.descriptions)

def analyze_coverage(results, outcomes):
    """Check that all available test cases are executed at least once."""
    available = collect_available_test_cases()
    for key in available:
        hits = outcomes[key].hits() if key in outcomes else 0
        if hits == 0:
            # Make this a warning, not an error, as long as we haven't
            # fixed this branch to have full coverage of test cases.
            results.warning('Test case not executed: {}', key)

def analyze_outcomes(outcomes):
    """Run all analyses on the given outcome collection."""
    results = Results()
    analyze_coverage(results, outcomes)
    return results

def read_outcome_file(outcome_file):
    """Parse an outcome file and return an outcome collection.

An outcome collection is a dictionary mapping keys to TestCaseOutcomes objects.
The keys are the test suite name and the test case description, separated
by a semicolon.
"""
    outcomes = {}
    with open(outcome_file, 'r', encoding='utf-8') as input_file:
        for line in input_file:
            (platform, config, suite, case, result, _cause) = line.split(';')
            key = ';'.join([suite, case])
            setup = ';'.join([platform, config])
            if key not in outcomes:
                outcomes[key] = TestCaseOutcomes()
            if result == 'PASS':
                outcomes[key].successes.append(setup)
            elif result == 'FAIL':
                outcomes[key].failures.append(setup)
    return outcomes

def analyze_outcome_file(outcome_file):
    """Analyze the given outcome file."""
    outcomes = read_outcome_file(outcome_file)
    return analyze_outcomes(outcomes)

def main():
    try:
        parser = argparse.ArgumentParser(description=__doc__)
        parser.add_argument('outcomes', metavar='OUTCOMES.CSV',
                            help='Outcome file to analyze')
        options = parser.parse_args()
        results = analyze_outcome_file(options.outcomes)
        if results.error_count > 0:
            sys.exit(1)
    except Exception: # pylint: disable=broad-except
        # Print the backtrace and exit explicitly with our chosen status.
        traceback.print_exc()
        sys.exit(120)

if __name__ == '__main__':
    main()
