<?php
namespace Psalm\Internal\Analyzer\Statements\Expression;

use PhpParser;
use Psalm\Internal\Analyzer\CommentAnalyzer;
use Psalm\Internal\Analyzer\FunctionLikeAnalyzer;
use Psalm\Internal\Analyzer\TraitAnalyzer;
use Psalm\Internal\Analyzer\Statements\ExpressionAnalyzer;
use Psalm\Internal\Analyzer\Statements\Expression\Fetch\PropertyFetchAnalyzer;
use Psalm\Internal\Analyzer\StatementsAnalyzer;
use Psalm\CodeLocation;
use Psalm\Context;
use Psalm\Exception\DocblockParseException;
use Psalm\Internal\FileManipulation\FileManipulationBuffer;
use Psalm\Issue\InvalidDocblock;
use Psalm\Issue\UnnecessaryVarAnnotation;
use Psalm\IssueBuffer;
use Psalm\Type;

class YieldAnalyzer
{
    /**
     * @param   StatementsAnalyzer           $statements_analyzer
     * @param   PhpParser\Node\Expr\Yield_  $stmt
     * @param   Context                     $context
     */
    public static function analyze(
        StatementsAnalyzer $statements_analyzer,
        PhpParser\Node\Expr\Yield_ $stmt,
        Context $context
    ) : bool {
        $doc_comment = $stmt->getDocComment();

        $var_comments = [];
        $var_comment_type = null;

        $codebase = $statements_analyzer->getCodebase();

        if ($doc_comment) {
            try {
                $var_comments = CommentAnalyzer::getTypeFromComment(
                    $doc_comment,
                    $statements_analyzer,
                    $statements_analyzer->getAliases()
                );
            } catch (DocblockParseException $e) {
                if (IssueBuffer::accepts(
                    new InvalidDocblock(
                        (string)$e->getMessage(),
                        new CodeLocation($statements_analyzer->getSource(), $stmt)
                    )
                )) {
                    // fall through
                }
            }

            foreach ($var_comments as $var_comment) {
                if (!$var_comment->type) {
                    continue;
                }

                $comment_type = \Psalm\Internal\Type\TypeExpander::expandUnion(
                    $codebase,
                    $var_comment->type,
                    $context->self,
                    $context->self ? new Type\Atomic\TNamedObject($context->self) : null,
                    $statements_analyzer->getParentFQCLN()
                );

                $type_location = null;

                if ($var_comment->type_start
                    && $var_comment->type_end
                    && $var_comment->line_number
                ) {
                    $type_location = new CodeLocation\DocblockTypeLocation(
                        $statements_analyzer,
                        $var_comment->type_start,
                        $var_comment->type_end,
                        $var_comment->line_number
                    );
                }

                if (!$var_comment->var_id) {
                    $var_comment_type = $comment_type;
                    continue;
                }

                if ($codebase->find_unused_variables
                    && $type_location
                    && isset($context->vars_in_scope[$var_comment->var_id])
                    && $context->vars_in_scope[$var_comment->var_id]->getId() === $comment_type->getId()
                ) {
                    $project_analyzer = $statements_analyzer->getProjectAnalyzer();

                    if ($codebase->alter_code
                        && isset($project_analyzer->getIssuesToFix()['UnnecessaryVarAnnotation'])
                    ) {
                        FileManipulationBuffer::addVarAnnotationToRemove($type_location);
                    } elseif (IssueBuffer::accepts(
                        new UnnecessaryVarAnnotation(
                            'The @var annotation for ' . $var_comment->var_id . ' is unnecessary',
                            $type_location
                        ),
                        [],
                        true
                    )) {
                        // fall through
                    }
                }

                $context->vars_in_scope[$var_comment->var_id] = $comment_type;
            }
        }

        if ($stmt->key) {
            $context->inside_call = true;
            if (ExpressionAnalyzer::analyze($statements_analyzer, $stmt->key, $context) === false) {
                return false;
            }
            $context->inside_call = false;
        }

        if ($stmt->value) {
            $context->inside_call = true;
            if (ExpressionAnalyzer::analyze($statements_analyzer, $stmt->value, $context) === false) {
                return false;
            }
            $context->inside_call = false;

            if ($var_comment_type) {
                $expression_type = clone $var_comment_type;
            } elseif ($stmt_var_type = $statements_analyzer->node_data->getType($stmt->value)) {
                $expression_type = clone $stmt_var_type;
            } else {
                $expression_type = Type::getMixed();
            }
        } else {
            $expression_type = Type::getEmpty();
        }

        $yield_type = null;

        foreach ($expression_type->getAtomicTypes() as $expression_atomic_type) {
            if ($expression_atomic_type instanceof Type\Atomic\TNamedObject) {
                $classlike_storage = $codebase->classlike_storage_provider->get($expression_atomic_type->value);

                if ($classlike_storage->yield) {
                    if ($expression_atomic_type instanceof Type\Atomic\TGenericObject) {
                        $yield_candidate_type = PropertyFetchAnalyzer::localizePropertyType(
                            $codebase,
                            clone $classlike_storage->yield,
                            $expression_atomic_type,
                            $classlike_storage,
                            $classlike_storage
                        );

                        if ($yield_type) {
                            $yield_type = Type::combineUnionTypes(
                                $yield_type,
                                $yield_candidate_type,
                                $codebase
                            );
                        } else {
                            $yield_type = $yield_candidate_type;
                        }
                    } else {
                        $yield_type = Type::getMixed();
                    }
                }
            }
        }

        if ($yield_type) {
            $expression_type->substitute($expression_type, $yield_type);
        }

        $statements_analyzer->node_data->setType($stmt, $expression_type);

        $source = $statements_analyzer->getSource();

        if ($source instanceof FunctionLikeAnalyzer
            && !($source->getSource() instanceof TraitAnalyzer)
        ) {
            $source->examineParamTypes($statements_analyzer, $context, $codebase, $stmt);

            $storage = $source->getFunctionLikeStorage($statements_analyzer);

            if ($storage->return_type && !$yield_type) {
                foreach ($storage->return_type->getAtomicTypes() as $atomic_return_type) {
                    if ($atomic_return_type instanceof Type\Atomic\TNamedObject
                        && $atomic_return_type->value === 'Generator'
                    ) {
                        if ($atomic_return_type instanceof Type\Atomic\TGenericObject) {
                            if (!$atomic_return_type->type_params[2]->isVoid()) {
                                $statements_analyzer->node_data->setType(
                                    $stmt,
                                    Type::combineUnionTypes(
                                        clone $atomic_return_type->type_params[2],
                                        $expression_type,
                                        $codebase
                                    )
                                );
                            }
                        } else {
                            $statements_analyzer->node_data->setType(
                                $stmt,
                                Type::combineUnionTypes(
                                    Type::getMixed(),
                                    $expression_type
                                )
                            );
                        }
                    }
                }
            }
        }

        return true;
    }
}