<?php

namespace App\Core\Database;

/**
 * NovaCore Database Blueprint
 * Schema builder for migrations
 */
class Blueprint
{
    private string $table;
    private array $columns = [];
    private array $indexes = [];
    private string $primaryKey = 'id';
    private array $timestamps = [];

    public function __construct(string $table)
    {
        $this->table = $table;
    }

    /**
     * Add primary key
     */
    public function id(string $column = 'id'): Column
    {
        $this->primaryKey = $column;
        $column = new Column('id', 'INT AUTO_INCREMENT PRIMARY KEY');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add string column
     */
    public function string(string $name, int $length = 255): Column
    {
        $column = new Column($name, "VARCHAR({$length})");
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add text column
     */
    public function text(string $name): Column
    {
        $column = new Column($name, 'TEXT');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add long text column
     */
    public function longText(string $name): Column
    {
        $column = new Column($name, 'LONGTEXT');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add integer column
     */
    public function integer(string $name, int $length = null): Column
    {
        $type = $length ? "INT({$length})" : 'INT';
        $column = new Column($name, $type);
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add big integer column
     */
    public function bigInteger(string $name): Column
    {
        $column = new Column($name, 'BIGINT');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add small integer column
     */
    public function smallInteger(string $name): Column
    {
        $column = new Column($name, 'SMALLINT');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add tiny integer column
     */
    public function tinyInteger(string $name): Column
    {
        $column = new Column($name, 'TINYINT');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add boolean column
     */
    public function boolean(string $name): Column
    {
        $column = new Column($name, 'BOOLEAN');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add decimal column
     */
    public function decimal(string $name, int $precision = 8, int $scale = 2): Column
    {
        $column = new Column($name, "DECIMAL({$precision}, {$scale})");
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add float column
     */
    public function float(string $name, int $precision = 8, int $scale = 2): Column
    {
        $column = new Column($name, "FLOAT({$precision}, {$scale})");
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add double column
     */
    public function double(string $name, int $precision = 8, int $scale = 2): Column
    {
        $column = new Column($name, "DOUBLE({$precision}, {$scale})");
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add date column
     */
    public function date(string $name): Column
    {
        $column = new Column($name, 'DATE');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add datetime column
     */
    public function datetime(string $name): Column
    {
        $column = new Column($name, 'DATETIME');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add timestamp column
     */
    public function timestamp(string $name): Column
    {
        $column = new Column($name, 'TIMESTAMP');
        $this->columns[] = $column;
        return $column;
    }

    /**
     * Add timestamps
     */
    public function timestamps(): void
    {
        $this->timestamp('created_at')->nullable();
        $this->timestamp('updated_at')->nullable();
    }

    /**
     * Add soft deletes
     */
    public function softDeletes(): void
    {
        $this->timestamp('deleted_at')->nullable();
    }

    /**
     * Add index
     */
    public function index(array $columns, string $name = null): void
    {
        if (!$name) {
            $name = $this->table . '_' . implode('_', $columns) . '_index';
        }

        $this->indexes[] = [
            'name' => $name,
            'columns' => $columns,
            'type' => 'INDEX'
        ];
    }

    /**
     * Add unique index
     */
    public function unique(array $columns, string $name = null): void
    {
        if (!$name) {
            $name = $this->table . '_' . implode('_', $columns) . '_unique';
        }

        $this->indexes[] = [
            'name' => $name,
            'columns' => $columns,
            'type' => 'UNIQUE'
        ];
    }

    /**
     * Add foreign key
     */
    public function foreign(string $column): ForeignKey
    {
        $foreignKey = new ForeignKey($column);
        $this->columns[] = $foreignKey;
        return $foreignKey;
    }

    /**
     * Generate SQL
     */
    public function toSql(): string
    {
        $sql = "CREATE TABLE `{$this->table}` (";

        $columnDefinitions = [];
        foreach ($this->columns as $column) {
            $columnDefinitions[] = $column->toSql();
        }

        $sql .= implode(', ', $columnDefinitions);
        $sql .= ")";

        return $sql;
    }
}

/**
 * Column definition
 */
class Column
{
    private string $name;
    private string $type;
    private bool $nullable = false;
    private $default = null;
    private bool $autoIncrement = false;
    private bool $primary = false;
    private bool $unique = false;

    public function __construct(string $name, string $type)
    {
        $this->name = $name;
        $this->type = $type;
    }

    /**
     * Set nullable
     */
    public function nullable(): self
    {
        $this->nullable = true;
        return $this;
    }

    /**
     * Set default value
     */
    public function default($value): self
    {
        $this->default = $value;
        return $this;
    }

    /**
     * Set auto increment
     */
    public function autoIncrement(): self
    {
        $this->autoIncrement = true;
        return $this;
    }

    /**
     * Set primary key
     */
    public function primary(): self
    {
        $this->primary = true;
        return $this;
    }

    /**
     * Set unique
     */
    public function unique(): self
    {
        $this->unique = true;
        return $this;
    }

    /**
     * Generate SQL
     */
    public function toSql(): string
    {
        $sql = "`{$this->name}` {$this->type}";

        if ($this->autoIncrement) {
            $sql .= " AUTO_INCREMENT";
        }

        if (!$this->nullable) {
            $sql .= " NOT NULL";
        }

        if ($this->default !== null) {
            $default = is_string($this->default) ? "'{$this->default}'" : $this->default;
            $sql .= " DEFAULT {$default}";
        }

        if ($this->unique) {
            $sql .= " UNIQUE";
        }

        if ($this->primary) {
            $sql .= " PRIMARY KEY";
        }

        return $sql;
    }
}

/**
 * Foreign key definition
 */
class ForeignKey
{
    private string $column;
    private string $references;
    private string $on;
    private string $onDelete = 'RESTRICT';
    private string $onUpdate = 'RESTRICT';

    public function __construct(string $column)
    {
        $this->column = $column;
    }

    /**
     * Set references
     */
    public function references(string $column): self
    {
        $this->references = $column;
        return $this;
    }

    /**
     * Set on table
     */
    public function on(string $table): self
    {
        $this->on = $table;
        return $this;
    }

    /**
     * Set on delete action
     */
    public function onDelete(string $action): self
    {
        $this->onDelete = $action;
        return $this;
    }

    /**
     * Set on update action
     */
    public function onUpdate(string $action): self
    {
        $this->onUpdate = $action;
        return $this;
    }

    /**
     * Generate SQL
     */
    public function toSql(): string
    {
        $sql = "`{$this->column}` INT";

        if ($this->references && $this->on) {
            $sql .= ", FOREIGN KEY (`{$this->column}`) REFERENCES `{$this->on}` (`{$this->references}`)";
            $sql .= " ON DELETE {$this->onDelete} ON UPDATE {$this->onUpdate}";
        }

        return $sql;
    }
}