class Mapper

final class Mapper {
    
    /**
     * @psalm-return array<string,list<int>>
     */
    public function codeUnitsToSourceLines(CodeUnitCollection $codeUnits) : array {
        $result = [];
        foreach ($codeUnits as $codeUnit) {
            $sourceFileName = $codeUnit->sourceFileName();
            if (!isset($result[$sourceFileName])) {
                $result[$sourceFileName] = [];
            }
            $result[$sourceFileName] = array_merge($result[$sourceFileName], $codeUnit->sourceLines());
        }
        foreach (array_keys($result) as $sourceFileName) {
            $result[$sourceFileName] = array_values(array_unique($result[$sourceFileName]));
            sort($result[$sourceFileName]);
        }
        ksort($result);
        return $result;
    }
    
    /**
     * @throws InvalidCodeUnitException
     * @throws ReflectionException
     */
    public function stringToCodeUnits(string $unit) : CodeUnitCollection {
        if (str_contains($unit, '::')) {
            [
                $firstPart,
                $secondPart,
            ] = explode('::', $unit);
            if ($this->isUserDefinedFunction($secondPart)) {
                return CodeUnitCollection::fromList(CodeUnit::forFunction($secondPart));
            }
            if ($this->isUserDefinedMethod($firstPart, $secondPart)) {
                return CodeUnitCollection::fromList(CodeUnit::forClassMethod($firstPart, $secondPart));
            }
            if ($this->isUserDefinedInterface($firstPart)) {
                return CodeUnitCollection::fromList(CodeUnit::forInterfaceMethod($firstPart, $secondPart));
            }
            if ($this->isUserDefinedTrait($firstPart)) {
                return CodeUnitCollection::fromList(CodeUnit::forTraitMethod($firstPart, $secondPart));
            }
        }
        else {
            if ($this->isUserDefinedClass($unit)) {
                $units = [
                    CodeUnit::forClass($unit),
                ];
                foreach ($this->reflectorForClass($unit)
                    ->getTraits() as $trait) {
                    if (!$trait->isUserDefined()) {
                        // @codeCoverageIgnoreStart
                        continue;
                        // @codeCoverageIgnoreEnd
                    }
                    $units[] = CodeUnit::forTrait($trait->getName());
                }
                return CodeUnitCollection::fromList(...$units);
            }
            if ($this->isUserDefinedInterface($unit)) {
                return CodeUnitCollection::fromList(CodeUnit::forInterface($unit));
            }
            if ($this->isUserDefinedTrait($unit)) {
                return CodeUnitCollection::fromList(CodeUnit::forTrait($unit));
            }
            if ($this->isUserDefinedFunction($unit)) {
                return CodeUnitCollection::fromList(CodeUnit::forFunction($unit));
            }
        }
        throw new InvalidCodeUnitException(sprintf('"%s" is not a valid code unit', $unit));
    }
    
    /**
     * @psalm-param class-string $className
     *
     * @throws ReflectionException
     */
    private function reflectorForClass(string $className) : ReflectionClass {
        try {
            return new ReflectionClass($className);
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException($e->getMessage(), $e->getCode(), $e);
        }
        // @codeCoverageIgnoreEnd
    }
    
    /**
     * @throws ReflectionException
     */
    private function isUserDefinedFunction(string $functionName) : bool {
        if (!function_exists($functionName)) {
            return false;
        }
        try {
            return (new ReflectionFunction($functionName))->isUserDefined();
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException($e->getMessage(), $e->getCode(), $e);
        }
        // @codeCoverageIgnoreEnd
    }
    
    /**
     * @throws ReflectionException
     */
    private function isUserDefinedClass(string $className) : bool {
        if (!class_exists($className)) {
            return false;
        }
        try {
            return (new ReflectionClass($className))->isUserDefined();
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException($e->getMessage(), $e->getCode(), $e);
        }
        // @codeCoverageIgnoreEnd
    }
    
    /**
     * @throws ReflectionException
     */
    private function isUserDefinedInterface(string $interfaceName) : bool {
        if (!interface_exists($interfaceName)) {
            return false;
        }
        try {
            return (new ReflectionClass($interfaceName))->isUserDefined();
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException($e->getMessage(), $e->getCode(), $e);
        }
        // @codeCoverageIgnoreEnd
    }
    
    /**
     * @throws ReflectionException
     */
    private function isUserDefinedTrait(string $traitName) : bool {
        if (!trait_exists($traitName)) {
            return false;
        }
        try {
            return (new ReflectionClass($traitName))->isUserDefined();
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException($e->getMessage(), $e->getCode(), $e);
        }
        // @codeCoverageIgnoreEnd
    }
    
    /**
     * @throws ReflectionException
     */
    private function isUserDefinedMethod(string $className, string $methodName) : bool {
        if (!class_exists($className)) {
            // @codeCoverageIgnoreStart
            return false;
            // @codeCoverageIgnoreEnd
        }
        if (!method_exists($className, $methodName)) {
            // @codeCoverageIgnoreStart
            return false;
            // @codeCoverageIgnoreEnd
        }
        try {
            return (new ReflectionMethod($className, $methodName))->isUserDefined();
            // @codeCoverageIgnoreStart
        } catch (\ReflectionException $e) {
            throw new ReflectionException($e->getMessage(), $e->getCode(), $e);
        }
        // @codeCoverageIgnoreEnd
    }

}