<?php

namespace LanguageServer\Protocol;

use PhpParser\Node;
use Exception;

/**
 * Represents information about programming constructs like variables, classes,
 * interfaces etc.
 */
class SymbolInformation
{
    /**
     * The name of this symbol.
     *
     * @var string
     */
    public $name;

    /**
     * The kind of this symbol.
     *
     * @var int
     */
    public $kind;

    /**
     * The location of this symbol.
     *
     * @var Location
     */
    public $location;

    /**
     * The name of the symbol containing this symbol.
     *
     * @var string|null
     */
    public $containerName;

    /**
     * Converts a Node to a SymbolInformation
     *
     * @param Node $node
     * @param string $fqn If given, $containerName will be extracted from it
     * @return self|null
     */
    public static function fromNode(Node $node, string $fqn = null)
    {
        $parent = $node->getAttribute('parentNode');
        $symbol = new self;

        if (
            $node instanceof Node\Expr\FuncCall
            && $node->name instanceof Node\Name
            && strtolower((string)$node->name) === 'define'
            && isset($node->args[0])
            && $node->args[0]->value instanceof Node\Scalar\String_
        ) {
            // constants with define() like
            // define('TEST_DEFINE_CONSTANT', false);
            $symbol->kind = SymbolKind::CONSTANT;
            $symbol->name = (string)$node->args[0]->value->value;
        } else if ($node instanceof Node\Stmt\Class_ || $node instanceof Node\Stmt\Trait_) {
            $symbol->kind = SymbolKind::CLASS_;
        } else if ($node instanceof Node\Stmt\Interface_) {
            $symbol->kind = SymbolKind::INTERFACE;
        } else if ($node instanceof Node\Name && $parent instanceof Node\Stmt\Namespace_) {
            $symbol->kind = SymbolKind::NAMESPACE;
        } else if ($node instanceof Node\Stmt\Function_) {
            $symbol->kind = SymbolKind::FUNCTION;
        } else if ($node instanceof Node\Stmt\ClassMethod && ($node->name === '__construct' || $node->name === '__destruct')) {
            $symbol->kind = SymbolKind::CONSTRUCTOR;
        } else if ($node instanceof Node\Stmt\ClassMethod) {
            $symbol->kind = SymbolKind::METHOD;
        } else if ($node instanceof Node\Stmt\PropertyProperty) {
            $symbol->kind = SymbolKind::PROPERTY;
        } else if ($node instanceof Node\Const_) {
            $symbol->kind = SymbolKind::CONSTANT;
        } else if (
            (
                ($node instanceof Node\Expr\Assign || $node instanceof Node\Expr\AssignOp)
                && $node->var instanceof Node\Expr\Variable
            )
            || $node instanceof Node\Expr\ClosureUse
            || $node instanceof Node\Param
        ) {
            $symbol->kind = SymbolKind::VARIABLE;
        } else {
            return null;
        }
        
        if (!isset($symbol->name)) {
            if ($node instanceof Node\Name) {
                $symbol->name = (string)$node;
            } else if ($node instanceof Node\Expr\Assign || $node instanceof Node\Expr\AssignOp) {
                $symbol->name = $node->var->name;
            } else if ($node instanceof Node\Expr\ClosureUse) {
                $symbol->name = $node->var;
            } else if (isset($node->name)) {
                $symbol->name = (string)$node->name;
            } else {
                return null;
            }
        }

        $symbol->location = Location::fromNode($node);
        if ($fqn !== null) {
            $parts = preg_split('/(::|->|\\\\)/', $fqn);
            array_pop($parts);
            $symbol->containerName = implode('\\', $parts);
        }
        return $symbol;
    }

    /**
     * @param string $name
     * @param int $kind
     * @param Location $location
     * @param string $containerName
     */
    public function __construct($name = null, $kind = null, $location = null, $containerName = null)
    {
        $this->name = $name;
        $this->kind = $kind;
        $this->location = $location;
        $this->containerName = $containerName;
    }
}