<?php

namespace Illuminate\Database\Schema;

use Illuminate\Database\Concerns\ParsesSearchPath;

class PostgresBuilder extends Builder
{
    use ParsesSearchPath {
        parseSearchPath as baseParseSearchPath;
    }

    /**
     * Create a database in the schema.
     *
     * @param  string  $name
     * @return bool
     */
    public function createDatabase($name)
    {
        return $this->connection->statement(
            $this->grammar->compileCreateDatabase($name, $this->connection)
        );
    }

    /**
     * Drop a database from the schema if the database exists.
     *
     * @param  string  $name
     * @return bool
     */
    public function dropDatabaseIfExists($name)
    {
        return $this->connection->statement(
            $this->grammar->compileDropDatabaseIfExists($name)
        );
    }

    /**
     * Determine if the given table exists.
     *
     * @param  string  $table
     * @return bool
     */
    public function hasTable($table)
    {
        [$database, $schema, $table] = $this->parseSchemaAndTable($table);

        $table = $this->connection->getTablePrefix().$table;

        return count($this->connection->selectFromWriteConnection(
            $this->grammar->compileTableExists(), [$database, $schema, $table]
        )) > 0;
    }

    /**
     * Get all of the table names for the database.
     *
     * @deprecated Will be removed in a future Laravel version.
     *
     * @return array
     */
    public function getAllTables()
    {
        return $this->connection->select(
            $this->grammar->compileGetAllTables(
                $this->parseSearchPath(
                    $this->connection->getConfig('search_path') ?: $this->connection->getConfig('schema')
                )
            )
        );
    }

    /**
     * Get all of the view names for the database.
     *
     * @deprecated Will be removed in a future Laravel version.
     *
     * @return array
     */
    public function getAllViews()
    {
        return $this->connection->select(
            $this->grammar->compileGetAllViews(
                $this->parseSearchPath(
                    $this->connection->getConfig('search_path') ?: $this->connection->getConfig('schema')
                )
            )
        );
    }

    /**
     * Drop all tables from the database.
     *
     * @return void
     */
    public function dropAllTables()
    {
        $tables = [];

        $excludedTables = $this->grammar->escapeNames(
            $this->connection->getConfig('dont_drop') ?? ['spatial_ref_sys']
        );

        $schemas = $this->grammar->escapeNames($this->getSchemas());

        foreach ($this->getTables() as $table) {
            $qualifiedName = $table['schema'].'.'.$table['name'];

            if (empty(array_intersect($this->grammar->escapeNames([$table['name'], $qualifiedName]), $excludedTables))
                && in_array($this->grammar->escapeNames([$table['schema']])[0], $schemas)) {
                $tables[] = $qualifiedName;
            }
        }

        if (empty($tables)) {
            return;
        }

        $this->connection->statement(
            $this->grammar->compileDropAllTables($tables)
        );
    }

    /**
     * Drop all views from the database.
     *
     * @return void
     */
    public function dropAllViews()
    {
        $views = [];

        $schemas = $this->grammar->escapeNames($this->getSchemas());

        foreach ($this->getViews() as $view) {
            if (in_array($this->grammar->escapeNames([$view['schema']])[0], $schemas)) {
                $views[] = $view['schema'].'.'.$view['name'];
            }
        }

        if (empty($views)) {
            return;
        }

        $this->connection->statement(
            $this->grammar->compileDropAllViews($views)
        );
    }

    /**
     * Get all of the type names for the database.
     *
     * @return array
     */
    public function getAllTypes()
    {
        return $this->connection->select(
            $this->grammar->compileGetAllTypes()
        );
    }

    /**
     * Drop all types from the database.
     *
     * @return void
     */
    public function dropAllTypes()
    {
        $types = [];

        foreach ($this->getAllTypes() as $row) {
            $row = (array) $row;

            $types[] = reset($row);
        }

        if (empty($types)) {
            return;
        }

        $this->connection->statement(
            $this->grammar->compileDropAllTypes($types)
        );
    }

    /**
     * Get the columns for a given table.
     *
     * @param  string  $table
     * @return array
     */
    public function getColumns($table)
    {
        [$database, $schema, $table] = $this->parseSchemaAndTable($table);

        $table = $this->connection->getTablePrefix().$table;

        $results = $this->connection->selectFromWriteConnection(
            $this->grammar->compileColumns($database, $schema, $table)
        );

        return $this->connection->getPostProcessor()->processColumns($results);
    }

    /**
     * Get the schemas for the connection.
     *
     * @return array
     */
    protected function getSchemas()
    {
        return $this->parseSearchPath(
            $this->connection->getConfig('search_path') ?: $this->connection->getConfig('schema') ?: 'public'
        );
    }

    /**
     * Parse the database object reference and extract the database, schema, and table.
     *
     * @param  string  $reference
     * @return array
     */
    protected function parseSchemaAndTable($reference)
    {
        $parts = explode('.', $reference);

        $database = $this->connection->getConfig('database');

        // If the reference contains a database name, we will use that instead of the
        // default database name for the connection. This allows the database name
        // to be specified in the query instead of at the full connection level.
        if (count($parts) === 3) {
            $database = $parts[0];
            array_shift($parts);
        }

        // We will use the default schema unless the schema has been specified in the
        // query. If the schema has been specified in the query then we can use it
        // instead of a default schema configured in the connection search path.
        $schema = $this->getSchemas()[0];

        if (count($parts) === 2) {
            $schema = $parts[0];
            array_shift($parts);
        }

        return [$database, $schema, $parts[0]];
    }

    /**
     * Parse the "search_path" configuration value into an array.
     *
     * @param  string|array|null  $searchPath
     * @return array
     */
    protected function parseSearchPath($searchPath)
    {
        return array_map(function ($schema) {
            return $schema === '$user'
                ? $this->connection->getConfig('username')
                : $schema;
        }, $this->baseParseSearchPath($searchPath));
    }
}
