# Default Test Runner.
#
# The Test::Mini::Runner is responsible for finding and running the
# appropriate tests, setting up output logging, and returning an appropriate
# status code.  For those looking to write tests with this framework, the
# points of note are as follows:
#
# * Tests are run automatically at process exit.
# * All test cases (subclasses of {Test::Mini::TestCase}) that have been
#   loaded at that time will be considered.  This includes indirect
#   subclasses.
# * Within each test case, all methods defined with a name matching
#   <tt>/^test.+/</tt> will be run.
#   * Each test will run in its own test case instance.
#   * Tests will be run in random order.
#   * #setup will be called before each test is run.
#   * #teardown will be called after each test is run.
#   * Inherited tests are *not* run.
# * Tests may be run via +`prove`+, by loading (via +use+, +do+ or +require+)
#   the files into another script, or by simply executing a file containing a
#   test case in the Perl interpreter.
#   * If you want to use a non-TAP output logger, +`prove`+ is not an option.
# * Options may be passed in either as command line options, or as environment
#   variables.
#   * Environment variable names are prefixed with 'TEST_MINI_'.
#   * Valid options are:
#     * +verbose+ - Specifies the logger's verbosity.
#     * +filter+ - Only tests with names matching this pattern should be run.
#     * +logger+ - Specifies an alternate output logger class.
#     * +seed+ - Specifies a random number seed; used to specify repeatable
#       test orderings.
package Test::Mini::Runner;
use strict;
use warnings;

use Getopt::Long;
use Try::Tiny;
use MRO::Compat;
use Test::Mini::TestCase;
use List::Util qw/ shuffle /;

# Constructor.
# Arguments may be provided explicitly to the constructor or implicitly via
# either @ARGV (parsed by {Getopt::Long}) or environment variables
# ("TEST_MINI_$option").
#
# @param [Hash] %args Initial state for the new instance.
# @option %args verbose (0) Logger verbosity.
# @option %args filter [String] ('')  Test name filter.
# @option %args logger [Class] (Test::Mini::Logger::TAP) Logger class name.
# @option %args seed [Integer] (a random number +< 64_000_000+) Randomness seed.
sub new {
    my ($class, %args) = @_;

    my %argv = (
        verbose   => $ENV{TEST_MINI_VERBOSE} || 0,
        filter    => $ENV{TEST_MINI_FILTER}  || '',
        logger    => $ENV{TEST_MINI_LOGGER}  || 'Test::Mini::Logger::TAP',
        seed      => $ENV{TEST_MINI_SEED}    || int(rand(64_000_000)),
    );

    GetOptions(\%argv, qw/ verbose=s filter=s logger=s seed=i /);
    return bless { %argv, %args, exit_code => 0 }, $class;
}

# @group Attribute Accessors

# @return Logger verbosity.
sub verbose {
    my $self = shift;
    return $self->{verbose};
}

# @return Test name filter.
sub filter {
    my $self = shift;
    return $self->{filter};
}

# @return Logger instance.
sub logger {
    my $self = shift;
    return $self->{logger};
}

# @return Randomness seed.
sub seed {
    my $self = shift;
    return $self->{seed};
}

# @return Exit code, representing the status of the test run.
sub exit_code {
    my $self = shift;
    return $self->{exit_code};
}

# @group Test Run Hooks

# Begins the test run.
# Loads and instantiates the test output logger, then dispatches to
# {#run_test_suite} (passing the {#filter} and {#seed}, as appropriate).
#
# @return The result of the {#run_test_suite} call.
sub run {
    my ($self) = @_;
    my $logger = $self->logger;
    try {
        eval "require $logger;" or die $@;
    }
    catch {
        eval "require Test::Mini::Logger::$logger;" or die $@;
    };

    $logger = $logger->new(verbose => $self->verbose);
    $self->{logger} = $logger;

    return $self->run_test_suite(filter => $self->filter, seed => $self->seed);
}

# Runs the test suite.
# Finds subclasses of {Test::Mini::TestCase}, and dispatches to
# {#run_test_case} with the name of each test case and a list test methods to
# be run.
#
# @param [Hash] %args
# @option %args [String] filter Test name filter.
# @option %args [String] seed Randomness seed.
# @return The value of {#exit_code}.
sub run_test_suite {
    my ($self, %args) = @_;
    $self->logger->begin_test_suite(%args);

    srand($args{seed});
    my @testcases = @{ mro::get_isarev('Test::Mini::TestCase') };

    # Since mro::get_isarev is guaranteed to never shrink, we should "double
    # check" our testcases, to make sure that they actually are *still*
    # subclasses of Test::Mini::TestCase.
    # @see http://search.cpan.org/dist/perl-5.12.2/ext/mro/mro.pm#mro::get_isarev($classname)
    @testcases = grep { $_->isa('Test::Mini::TestCase') } @testcases;

    $self->{exit_code} = 255 unless @testcases;

    for my $tc (shuffle @testcases) {
        no strict 'refs';
        my @tests = grep { /^test.+/ && defined &{"$tc\::$_"}} keys %{"$tc\::"};
        $self->run_test_case($tc, grep { $_ =~ qr/$args{filter}/ } @tests);
    }

    $self->logger->finish_test_suite($self->exit_code);
    return $self->exit_code;
}

# Runs tests in a test case.
#
# @param [Class] $tc The test case to run.
# @param [Array<String>] @tests A list of tests to be run.
sub run_test_case {
    my ($self, $tc, @tests) = @_;
    $self->logger->begin_test_case($tc, @tests);

    $self->{exit_code} = 127 unless @{[
        (@tests, grep { $_->isa($tc) } @{ mro::get_isarev($tc) })
    ]};

    $self->run_test($tc, $_) for shuffle @tests;

    $self->logger->finish_test_case($tc, @tests);
    return scalar @tests;
}

# Runs a specific test.
#
# @param [Class] $tc The test case owning the test method.
# @param [String] $test The name of the test method to be run.
# @return [Integer] The number of assertions called by the test.
sub run_test {
    my ($self, $tc, $test) = @_;
    $self->logger->begin_test($tc, $test);

    my $instance = $tc->new(name => $test);
    my $assertions = $instance->run($self);

    $self->logger->finish_test($tc, $test, $assertions);
    return $assertions;
}

# @group Callbacks

# Callback for passing tests.
#
# @param [Class] $tc The test case owning the test method.
# @param [String] $test The name of the passing test.
sub pass {
    my ($self, $tc, $test) = @_;
    $self->logger->pass($tc, $test);
}

# Callback for skipped tests.
#
# @param [Class] $tc The test case owning the test method.
# @param [String] $test The name of the skipped test.
# @param [Test::Mini::Exception::Skip] $e The exception object.
sub skip {
    my ($self, $tc, $test, $e) = @_;
    $self->logger->skip($tc, $test, $e);
}

# Callback for failing tests.
#
# @param [Class] $tc The test case owning the test method.
# @param [String] $test The name of the failed test.
# @param [Test::Mini::Exception::Assert] $e The exception object.
sub fail {
    my ($self, $tc, $test, $e) = @_;
    $self->{exit_code} = 1 unless $self->{exit_code};
    $self->logger->fail($tc, $test, $e);
}

# Callback for dying tests.
#
# @param [Class] $tc The test case owning the test method.
# @param [String] $test The name of the test with an error.
# @param [Test::Mini::Exception] $e The exception object.
sub error {
    my ($self, $tc, $test, $e) = @_;
    $self->{exit_code} = 1 unless $self->{exit_code};
    $self->logger->error($tc, $test, $e);
}

1;