<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\db\pgsql;

use yii\db\Expression;
use yii\db\TableSchema;
use yii\db\ColumnSchema;

/**
 * Schema is the class for retrieving metadata from a PostgreSQL database
 * (version 9.x and above).
 *
 * @author Gevik Babakhani <gevikb@gmail.com>
 * @since 2.0
 */
class Schema extends \yii\db\Schema
{
    /**
     * @var string the default schema used for the current session.
     */
    public $defaultSchema = 'public';
    /**
     * @var array mapping from physical column types (keys) to abstract
     * column types (values)
     * @see http://www.postgresql.org/docs/current/static/datatype.html#DATATYPE-TABLE
     */
    public $typeMap = [
        'bit' => self::TYPE_INTEGER,
        'bit varying' => self::TYPE_INTEGER,
        'varbit' => self::TYPE_INTEGER,

        'bool' => self::TYPE_BOOLEAN,
        'boolean' => self::TYPE_BOOLEAN,

        'box' => self::TYPE_STRING,
        'circle' => self::TYPE_STRING,
        'point' => self::TYPE_STRING,
        'line' => self::TYPE_STRING,
        'lseg' => self::TYPE_STRING,
        'polygon' => self::TYPE_STRING,
        'path' => self::TYPE_STRING,

        'character' => self::TYPE_STRING,
        'char' => self::TYPE_STRING,
        'character varying' => self::TYPE_STRING,
        'varchar' => self::TYPE_STRING,
        'text' => self::TYPE_TEXT,

        'bytea' => self::TYPE_BINARY,

        'cidr' => self::TYPE_STRING,
        'inet' => self::TYPE_STRING,
        'macaddr' => self::TYPE_STRING,

        'real' => self::TYPE_FLOAT,
        'float4' => self::TYPE_FLOAT,
        'double precision' => self::TYPE_DOUBLE,
        'float8' => self::TYPE_DOUBLE,
        'decimal' => self::TYPE_DECIMAL,
        'numeric' => self::TYPE_DECIMAL,

        'money' => self::TYPE_MONEY,

        'smallint' => self::TYPE_SMALLINT,
        'int2' => self::TYPE_SMALLINT,
        'int4' => self::TYPE_INTEGER,
        'int' => self::TYPE_INTEGER,
        'integer' => self::TYPE_INTEGER,
        'bigint' => self::TYPE_BIGINT,
        'int8' => self::TYPE_BIGINT,
        'oid' => self::TYPE_BIGINT, // should not be used. it's pg internal!

        'smallserial' => self::TYPE_SMALLINT,
        'serial2' => self::TYPE_SMALLINT,
        'serial4' => self::TYPE_INTEGER,
        'serial' => self::TYPE_INTEGER,
        'bigserial' => self::TYPE_BIGINT,
        'serial8' => self::TYPE_BIGINT,
        'pg_lsn' => self::TYPE_BIGINT,

        'date' => self::TYPE_DATE,
        'interval' => self::TYPE_STRING,
        'time without time zone' => self::TYPE_TIME,
        'time' => self::TYPE_TIME,
        'time with time zone' => self::TYPE_TIME,
        'timetz' => self::TYPE_TIME,
        'timestamp without time zone' => self::TYPE_TIMESTAMP,
        'timestamp' => self::TYPE_TIMESTAMP,
        'timestamp with time zone' => self::TYPE_TIMESTAMP,
        'timestamptz' => self::TYPE_TIMESTAMP,
        'abstime' => self::TYPE_TIMESTAMP,

        'tsquery' => self::TYPE_STRING,
        'tsvector' => self::TYPE_STRING,
        'txid_snapshot' => self::TYPE_STRING,

        'unknown' => self::TYPE_STRING,

        'uuid' => self::TYPE_STRING,
        'json' => self::TYPE_STRING,
        'jsonb' => self::TYPE_STRING,
        'xml' => self::TYPE_STRING
    ];


    /**
     * Creates a query builder for the PostgreSQL database.
     * @return QueryBuilder query builder instance
     */
    public function createQueryBuilder()
    {
        return new QueryBuilder($this->db);
    }

    /**
     * Resolves the table name and schema name (if any).
     * @param TableSchema $table the table metadata object
     * @param string $name the table name
     */
    protected function resolveTableNames($table, $name)
    {
        $parts = explode('.', str_replace('"', '', $name));

        if (isset($parts[1])) {
            $table->schemaName = $parts[0];
            $table->name = $parts[1];
        } else {
            $table->schemaName = $this->defaultSchema;
            $table->name = $name;
        }

        $table->fullName = $table->schemaName !== $this->defaultSchema ? $table->schemaName . '.' . $table->name : $table->name;
    }

    /**
     * Quotes a table name for use in a query.
     * A simple table name has no schema prefix.
     * @param string $name table name
     * @return string the properly quoted table name
     */
    public function quoteSimpleTableName($name)
    {
        return strpos($name, '"') !== false ? $name : '"' . $name . '"';
    }

    /**
     * Loads the metadata for the specified table.
     * @param string $name table name
     * @return TableSchema|null driver dependent table metadata. Null if the table does not exist.
     */
    public function loadTableSchema($name)
    {
        $table = new TableSchema();
        $this->resolveTableNames($table, $name);
        if ($this->findColumns($table)) {
            $this->findConstraints($table);

            return $table;
        } else {
            return null;
        }
    }

    /**
     * Returns all table names in the database.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * @return array all table names in the database. The names have NO schema name prefix.
     */
    protected function findTableNames($schema = '')
    {
        if ($schema === '') {
            $schema = $this->defaultSchema;
        }
        $sql = <<<EOD
SELECT table_name, table_schema FROM information_schema.tables
WHERE table_schema=:schema AND table_type='BASE TABLE'
EOD;
        $command = $this->db->createCommand($sql);
        $command->bindParam(':schema', $schema);
        $rows = $command->queryAll();
        $names = [];
        foreach ($rows as $row) {
            $names[] = $row['table_name'];
        }

        return $names;
    }

    /**
     * Collects the foreign key column details for the given table.
     * @param TableSchema $table the table metadata
     */
    protected function findConstraints($table)
    {

        $tableName = $this->quoteValue($table->name);
        $tableSchema = $this->quoteValue($table->schemaName);

        //We need to extract the constraints de hard way since:
        //http://www.postgresql.org/message-id/26677.1086673982@sss.pgh.pa.us

        $sql = <<<SQL
select
    (select string_agg(attname,',') attname from pg_attribute where attrelid=ct.conrelid and attnum = any(ct.conkey)) as columns,
    fc.relname as foreign_table_name,
    fns.nspname as foreign_table_schema,
    (select string_agg(attname,',') attname from pg_attribute where attrelid=ct.confrelid and attnum = any(ct.confkey)) as foreign_columns
from
    pg_constraint ct
    inner join pg_class c on c.oid=ct.conrelid
    inner join pg_namespace ns on c.relnamespace=ns.oid
    left join pg_class fc on fc.oid=ct.confrelid
    left join pg_namespace fns on fc.relnamespace=fns.oid

where
    ct.contype='f'
    and c.relname={$tableName}
    and ns.nspname={$tableSchema}
SQL;

        $constraints = $this->db->createCommand($sql)->queryAll();
        foreach ($constraints as $constraint) {
            $columns = explode(',', $constraint['columns']);
            $fcolumns = explode(',', $constraint['foreign_columns']);
            if ($constraint['foreign_table_schema'] !== $this->defaultSchema) {
                $foreignTable = $constraint['foreign_table_schema'] . '.' . $constraint['foreign_table_name'];
            } else {
                $foreignTable = $constraint['foreign_table_name'];
            }
            $citem = [$foreignTable];
            foreach ($columns as $idx => $column) {
                $citem[$column] = $fcolumns[$idx];
            }
            $table->foreignKeys[] = $citem;
        }
    }

    /**
     * Gets information about given table unique indexes.
     * @param TableSchema $table the table metadata
     * @return array with index names, columns and if it is an expression tree
     */
    protected function getUniqueIndexInformation($table)
    {
        $tableName = $this->quoteValue($table->name);
        $tableSchema = $this->quoteValue($table->schemaName);

        $sql = <<<SQL
SELECT
    i.relname as indexname,
    ARRAY(
        SELECT pg_get_indexdef(idx.indexrelid, k + 1, True)
        FROM generate_subscripts(idx.indkey, 1) AS k
        ORDER BY k
    ) AS indexcolumns,
    idx.indexprs IS NOT NULL AS indexprs
FROM pg_index idx
INNER JOIN pg_class i ON i.oid = idx.indexrelid
INNER JOIN pg_class c ON c.oid = idx.indrelid
INNER JOIN pg_namespace ns ON c.relnamespace = ns.oid
WHERE idx.indisprimary != True
AND idx.indisunique = True
AND c.relname = {$tableName}
AND ns.nspname = {$tableSchema}
;
SQL;

        return $this->db->createCommand($sql)->queryAll();
    }

    /**
     * Returns all unique indexes for the given table.
     * Each array element is of the following structure:
     *
     * ~~~
     * [
     *  'IndexName1' => ['col1' [, ...]],
     *  'IndexName2' => ['col2' [, ...]],
     * ]
     * ~~~
     *
     * @param TableSchema $table the table metadata
     * @return array all unique indexes for the given table.
     */
    public function findUniqueIndexes($table)
    {
        $indexes = $this->getUniqueIndexInformation($table);
        $uniqueIndexes = [];

        foreach ($indexes as $index) {
            $indexName = $index['indexname'];

            if ($index['indexprs']) {
                // Index is an expression like "lower(colname::text)"
                $indexColumns = preg_replace("/.*\(([^\:]+).*/mi", "$1", $index['indexcolumns']);
            } else {
                $indexColumns = array_map('trim', explode(',', str_replace(['{', '}', '"', '\\'], '', $index['indexcolumns'])));
            }

            $uniqueIndexes[$indexName] = $indexColumns;

        }

        return $uniqueIndexes;
    }

    /**
     * Collects the metadata of table columns.
     * @param TableSchema $table the table metadata
     * @return boolean whether the table exists in the database
     */
    protected function findColumns($table)
    {
        $tableName = $this->db->quoteValue($table->name);
        $schemaName = $this->db->quoteValue($table->schemaName);
        $sql = <<<SQL
SELECT
    d.nspname AS table_schema,
    c.relname AS table_name,
    a.attname AS column_name,
    t.typname AS data_type,
    a.attlen AS character_maximum_length,
    pg_catalog.col_description(c.oid, a.attnum) AS column_comment,
    a.atttypmod AS modifier,
    a.attnotnull = false AS is_nullable,
    CAST(pg_get_expr(ad.adbin, ad.adrelid) AS varchar) AS column_default,
    coalesce(pg_get_expr(ad.adbin, ad.adrelid) ~ 'nextval',false) AS is_autoinc,
    array_to_string((select array_agg(enumlabel) from pg_enum where enumtypid=a.atttypid)::varchar[],',') as enum_values,
    CASE atttypid
         WHEN 21 /*int2*/ THEN 16
         WHEN 23 /*int4*/ THEN 32
         WHEN 20 /*int8*/ THEN 64
         WHEN 1700 /*numeric*/ THEN
              CASE WHEN atttypmod = -1
               THEN null
               ELSE ((atttypmod - 4) >> 16) & 65535
               END
         WHEN 700 /*float4*/ THEN 24 /*FLT_MANT_DIG*/
         WHEN 701 /*float8*/ THEN 53 /*DBL_MANT_DIG*/
         ELSE null
      END   AS numeric_precision,
      CASE
        WHEN atttypid IN (21, 23, 20) THEN 0
        WHEN atttypid IN (1700) THEN
        CASE
            WHEN atttypmod = -1 THEN null
            ELSE (atttypmod - 4) & 65535
        END
           ELSE null
      END AS numeric_scale,
    CAST(
             information_schema._pg_char_max_length(information_schema._pg_truetypid(a, t), information_schema._pg_truetypmod(a, t))
             AS numeric
    ) AS size,
    a.attnum = any (ct.conkey) as is_pkey
FROM
    pg_class c
    LEFT JOIN pg_attribute a ON a.attrelid = c.oid
    LEFT JOIN pg_attrdef ad ON a.attrelid = ad.adrelid AND a.attnum = ad.adnum
    LEFT JOIN pg_type t ON a.atttypid = t.oid
    LEFT JOIN pg_namespace d ON d.oid = c.relnamespace
    LEFT join pg_constraint ct on ct.conrelid=c.oid and ct.contype='p'
WHERE
    a.attnum > 0 and t.typname != ''
    and c.relname = {$tableName}
    and d.nspname = {$schemaName}
ORDER BY
    a.attnum;
SQL;

        $columns = $this->db->createCommand($sql)->queryAll();
        if (empty($columns)) {
            return false;
        }
        foreach ($columns as $column) {
            $column = $this->loadColumnSchema($column);
            $table->columns[$column->name] = $column;
            if ($column->isPrimaryKey) {
                $table->primaryKey[] = $column->name;
                if ($table->sequenceName === null && preg_match("/nextval\\('\"?\\w+\"?\.?\"?\\w+\"?'(::regclass)?\\)/", $column->defaultValue) === 1) {
                    $table->sequenceName = preg_replace(['/nextval/', '/::/', '/regclass/', '/\'\)/', '/\(\'/'], '', $column->defaultValue);
                }
                $column->defaultValue = null;
            } elseif ($column->defaultValue) {
                if ($column->type === 'timestamp' && $column->defaultValue === 'now()') {
                    $column->defaultValue = new Expression($column->defaultValue);
                } elseif ($column->type === 'boolean') {
                        $column->defaultValue = ($column->defaultValue === 'true');
                } elseif (stripos($column->dbType, 'bit') === 0 || stripos($column->dbType, 'varbit') === 0) {
                    $column->defaultValue = bindec(trim($column->defaultValue, 'B\''));
                } elseif (preg_match("/^'(.*?)'::/", $column->defaultValue, $matches)) {
                    $column->defaultValue = $matches[1];
                } elseif (preg_match("/^(.*?)::/", $column->defaultValue, $matches)) {
                    $column->defaultValue = $column->phpTypecast($matches[1]);
                } else {
                    $column->defaultValue = $column->phpTypecast($column->defaultValue);
                }
            }
        }

        return true;
    }

    /**
     * Loads the column information into a [[ColumnSchema]] object.
     * @param array $info column information
     * @return ColumnSchema the column schema object
     */
    protected function loadColumnSchema($info)
    {
        $column = $this->createColumnSchema();
        $column->allowNull = $info['is_nullable'];
        $column->autoIncrement = $info['is_autoinc'];
        $column->comment = $info['column_comment'];
        $column->dbType = $info['data_type'];
        $column->defaultValue = $info['column_default'];
        $column->enumValues = ($info['enum_values'] !== null) ? explode(',', str_replace(["''"], ["'"], $info['enum_values'])) : null;
        $column->unsigned = false; // has no meaning in PG
        $column->isPrimaryKey = $info['is_pkey'];
        $column->name = $info['column_name'];
        $column->precision = $info['numeric_precision'];
        $column->scale = $info['numeric_scale'];
        $column->size = $info['size'] === null ? null : (int) $info['size'];
        if (isset($this->typeMap[$column->dbType])) {
            $column->type = $this->typeMap[$column->dbType];
        } else {
            $column->type = self::TYPE_STRING;
        }
        $column->phpType = $this->getColumnPhpType($column);

        return $column;
    }
}
