class CodeCoverage

final class CodeCoverage {
    
    /**
     * @psalm-param class-string $className
     * @psalm-param non-empty-string $methodName
     *
     * @psalm-return array<string,list<int>>|false
     *
     * @throws CodeCoverageException
     */
    public function linesToBeCovered(string $className, string $methodName) : array|false {
        if (!$this->shouldCodeCoverageBeCollectedFor($className, $methodName)) {
            return false;
        }
        $metadataForClass = Registry::parser()->forClass($className);
        $classShortcut = null;
        if ($metadataForClass->isCoversDefaultClass()
            ->isNotEmpty()) {
            if (count($metadataForClass->isCoversDefaultClass()) > 1) {
                throw new CodeCoverageException(sprintf('More than one @coversDefaultClass annotation for class or interface "%s"', $className));
            }
            $metadata = $metadataForClass->isCoversDefaultClass()
                ->asArray()[0];
            assert($metadata instanceof CoversDefaultClass);
            $classShortcut = $metadata->className();
        }
        $codeUnits = CodeUnitCollection::fromList();
        $mapper = new Mapper();
        foreach (Registry::parser()->forClassAndMethod($className, $methodName) as $metadata) {
            if (!$metadata->isCoversClass() && !$metadata->isCoversFunction() && !$metadata->isCovers()) {
                continue;
            }
            assert($metadata instanceof CoversClass || $metadata instanceof CoversFunction || $metadata instanceof Covers);
            if ($metadata->isCoversClass() || $metadata->isCoversFunction()) {
                $codeUnits = $codeUnits->mergeWith($this->mapToCodeUnits($metadata));
            }
            elseif ($metadata->isCovers()) {
                assert($metadata instanceof Covers);
                $target = $metadata->target();
                if (interface_exists($target)) {
                    throw new InvalidCoversTargetException(sprintf('Trying to @cover interface "%s".', $target));
                }
                if ($classShortcut !== null && str_starts_with($target, '::')) {
                    $target = $classShortcut . $target;
                }
                try {
                    $codeUnits = $codeUnits->mergeWith($mapper->stringToCodeUnits($target));
                } catch (InvalidCodeUnitException $e) {
                    throw new InvalidCoversTargetException(sprintf('"@covers %s" is invalid', $target), $e->getCode(), $e);
                }
            }
        }
        return $mapper->codeUnitsToSourceLines($codeUnits);
    }
    
    /**
     * @psalm-param class-string $className
     * @psalm-param non-empty-string $methodName
     *
     * @psalm-return array<string,list<int>>
     *
     * @throws CodeCoverageException
     */
    public function linesToBeUsed(string $className, string $methodName) : array {
        $metadataForClass = Registry::parser()->forClass($className);
        $classShortcut = null;
        if ($metadataForClass->isUsesDefaultClass()
            ->isNotEmpty()) {
            if (count($metadataForClass->isUsesDefaultClass()) > 1) {
                throw new CodeCoverageException(sprintf('More than one @usesDefaultClass annotation for class or interface "%s"', $className));
            }
            $metadata = $metadataForClass->isUsesDefaultClass()
                ->asArray()[0];
            assert($metadata instanceof UsesDefaultClass);
            $classShortcut = $metadata->className();
        }
        $codeUnits = CodeUnitCollection::fromList();
        $mapper = new Mapper();
        foreach (Registry::parser()->forClassAndMethod($className, $methodName) as $metadata) {
            if (!$metadata->isUsesClass() && !$metadata->isUsesFunction() && !$metadata->isUses()) {
                continue;
            }
            assert($metadata instanceof UsesClass || $metadata instanceof UsesFunction || $metadata instanceof Uses);
            if ($metadata->isUsesClass() || $metadata->isUsesFunction()) {
                $codeUnits = $codeUnits->mergeWith($this->mapToCodeUnits($metadata));
            }
            elseif ($metadata->isUses()) {
                assert($metadata instanceof Uses);
                $target = $metadata->target();
                if ($classShortcut !== null && str_starts_with($target, '::')) {
                    $target = $classShortcut . $target;
                }
                try {
                    $codeUnits = $codeUnits->mergeWith($mapper->stringToCodeUnits($target));
                } catch (InvalidCodeUnitException $e) {
                    throw new InvalidCoversTargetException(sprintf('"@uses %s" is invalid', $target), $e->getCode(), $e);
                }
            }
        }
        return $mapper->codeUnitsToSourceLines($codeUnits);
    }
    
    /**
     * @psalm-return array<string,list<int>>
     */
    public function linesToBeIgnored(TestSuite $testSuite) : array {
        $codeUnits = CodeUnitCollection::fromList();
        $mapper = new Mapper();
        foreach ($this->testCaseClassesIn($testSuite) as $testCaseClassName) {
            $codeUnits = $codeUnits->mergeWith($this->codeUnitsIgnoredBy($testCaseClassName));
        }
        return $mapper->codeUnitsToSourceLines($codeUnits);
    }
    
    /**
     * @psalm-param class-string $className
     * @psalm-param non-empty-string $methodName
     */
    public function shouldCodeCoverageBeCollectedFor(string $className, string $methodName) : bool {
        $metadataForClass = Registry::parser()->forClass($className);
        $metadataForMethod = Registry::parser()->forMethod($className, $methodName);
        if ($metadataForMethod->isCoversNothing()
            ->isNotEmpty()) {
            return false;
        }
        if ($metadataForMethod->isCovers()
            ->isNotEmpty() || $metadataForMethod->isCoversClass()
            ->isNotEmpty() || $metadataForMethod->isCoversFunction()
            ->isNotEmpty()) {
            return true;
        }
        if ($metadataForClass->isCoversNothing()
            ->isNotEmpty()) {
            return false;
        }
        return true;
    }
    
    /**
     * @psalm-return list<class-string>
     */
    private function testCaseClassesIn(TestSuite $testSuite) : array {
        $classNames = [];
        foreach (new RecursiveIteratorIterator($testSuite) as $test) {
            $classNames[] = $test::class;
        }
        return array_values(array_unique($classNames));
    }
    
    /**
     * @psalm-param class-string $className
     */
    private function codeUnitsIgnoredBy(string $className) : CodeUnitCollection {
        $codeUnits = CodeUnitCollection::fromList();
        $mapper = new Mapper();
        foreach (Registry::parser()->forClass($className) as $metadata) {
            if ($metadata instanceof IgnoreClassForCodeCoverage) {
                $codeUnits = $codeUnits->mergeWith($mapper->stringToCodeUnits($metadata->className()));
            }
            if ($metadata instanceof IgnoreMethodForCodeCoverage) {
                $codeUnits = $codeUnits->mergeWith($mapper->stringToCodeUnits($metadata->className() . '::' . $metadata->methodName()));
            }
            if ($metadata instanceof IgnoreFunctionForCodeCoverage) {
                $codeUnits = $codeUnits->mergeWith($mapper->stringToCodeUnits('::' . $metadata->functionName()));
            }
        }
        return $codeUnits;
    }
    
    /**
     * @throws InvalidCoversTargetException
     */
    private function mapToCodeUnits(CoversClass|CoversFunction|UsesClass|UsesFunction $metadata) : CodeUnitCollection {
        $mapper = new Mapper();
        try {
            return $mapper->stringToCodeUnits($metadata->asStringForCodeUnitMapper());
        } catch (CodeUnitException $e) {
            if ($metadata->isCoversClass() || $metadata->isUsesClass()) {
                if (interface_exists($metadata->className())) {
                    $type = 'Interface';
                }
                else {
                    $type = 'Class';
                }
            }
            else {
                $type = 'Function';
            }
            throw new InvalidCoversTargetException(sprintf('%s "%s" is not a valid target for code coverage', $type, $metadata->asStringForCodeUnitMapper()), $e->getCode(), $e);
        }
    }

}