<?php
/**
 * @author Daniel J. Summers <daniel@bitbadger.solutions>
 * @license MIT
 */

declare(strict_types=1);

namespace BitBadger\PDODocument;

use Exception;

/**
 * Criteria for a field WHERE clause
 */
class Field
{
    /**
     * Constructor
     *
     * NOTE: Use static construction methods rather than using this directly; different properties are required
     *       depending on the operation being performed. This is only public so it can be tested.
     *
     * @param string $fieldName The name of the field
     * @param Op $op The operation by which the field will be compared
     * @param mixed $value The value of the field
     * @param string $paramName The name of the parameter to which this should be bound
     * @param string $qualifier A table qualifier for the `data` column
     */
    public function __construct(public string $fieldName = '', public Op $op = Op::Equal, public mixed $value = '',
                                public string $paramName = '', public string $qualifier = '') { }

    /**
     * Append the parameter name and value to the given associative array
     *
     * @param array<string, mixed> $existing The existing parameters
     * @return array<string, mixed> The given parameter array with this field's name and value(s) appended
     */
    public function appendParameter(array $existing): array
    {
        switch ($this->op) {
            case Op::Exists:
            case Op::NotExists:
                break;
            case Op::Between:
                $existing["{$this->paramName}min"] = $this->value[0];
                $existing["{$this->paramName}max"] = $this->value[1];
                break;
            case Op::In:
                for ($idx = 0; $idx < count($this->value); $idx++) {
                    $existing["{$this->paramName}_$idx"] = $this->value[$idx];
                }
                break;
            case Op::InArray:
                $mkString = Configuration::mode("Append parameters for InArray condition") === Mode::PgSQL;
                $values   = $this->value['values'];
                for ($idx = 0; $idx < count($values); $idx++) {
                    $existing["{$this->paramName}_$idx"] = $mkString ? "$values[$idx]" : $values[$idx];
                }
                break;
            default:
                $existing[$this->paramName] = $this->value;
        }
        return $existing;
    }

    /**
     * Derive the path for this field
     *
     * @param bool $asJSON Whether the field should be treated as JSON in the query (optional, default false)
     * @return string The path for this field
     * @throws Exception If the database mode has not been set
     */
    public function path(bool $asJSON = false): string
    {
        $extra = $asJSON ? '' : '>';
        if (str_contains($this->fieldName, '.')) {
            $mode = Configuration::mode('determine field path');
            if ($mode === Mode::PgSQL) {
                return "data#>$extra'{" . implode(',', explode('.', $this->fieldName)) . "}'";
            }
            if ($mode === Mode::SQLite) {
                $parts = explode('.', $this->fieldName);
                $last  = array_pop($parts);
                return "data->'" . implode("'->'", $parts) . "'->$extra'$last'";
            }
        }
        return "data->$extra'$this->fieldName'";
    }

    /**
     * Get the WHERE clause fragment for this parameter
     *
     * @return string The WHERE clause fragment for this parameter
     * @throws Exception|DocumentException If the database mode has not been set
     */
    public function toWhere(): string
    {
        $mode        = Configuration::mode('make field WHERE clause');
        $fieldName   = (empty($this->qualifier) ? '' : "$this->qualifier.") . $this->path($this->op === Op::InArray);
        $fieldPath   = match ($mode) {
            Mode::PgSQL => match (true) {
                $this->op === Op::Between,
                $this->op === Op::In      => is_numeric($this->value[0]) ? "($fieldName)::numeric" : $fieldName,
                is_numeric($this->value)  => "($fieldName)::numeric",
                default                   => $fieldName,
            },
            default => $fieldName,
        };
        $criteria = match ($this->op) {
            Op::Exists,
            Op::NotExists => '',
            Op::Between   => " {$this->paramName}min AND {$this->paramName}max",
            Op::In        => ' (' . $this->inParameterNames() . ')',
            Op::InArray   => $mode === Mode::PgSQL ? ' ARRAY[' . $this->inParameterNames() . ']' : '',
            default       => " $this->paramName",
        };
        return $mode === Mode::SQLite && $this->op === Op::InArray
            ? "EXISTS (SELECT 1 FROM json_each({$this->value['table']}.data, '\$.$this->fieldName') WHERE value IN ("
                    . $this->inParameterNames() . '))'
            : $fieldPath . ' ' . $this->op->toSQL() . $criteria;
    }

    /**
     * Create parameter names for an IN clause
     *
     * @return string A comma-delimited string of parameter names
     */
    private function inParameterNames(): string
    {
        $values = $this->op === Op::In ? $this->value : $this->value['values'];
        return implode(', ',
            array_map(fn($value, $key) => "{$this->paramName}_$key", $values, range(0, count($values) - 1)));
    }

    /**
     * Create an equals (=) field criterion
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for which equality will be checked
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function equal(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return new self($fieldName, Op::Equal, $value, $paramName);
    }

    /**
     * Create an equals (=) field criterion _(alias for `Field.equal`)_
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for which equality will be checked
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function EQ(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return self::equal($fieldName, $value, $paramName);
    }

    /**
     * Create a greater than (>) field criterion
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the greater than comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function greater(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return new self($fieldName, Op::Greater, $value, $paramName);
    }

    /**
     * Create a greater than (>) field criterion _(alias for `Field.greater`)_
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the greater than comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function GT(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return self::greater($fieldName, $value, $paramName);
    }

    /**
     * Create a greater than or equal to (>=) field criterion
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the greater than or equal to comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function greaterOrEqual(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return new self($fieldName, Op::GreaterOrEqual, $value, $paramName);
    }

    /**
     * Create a greater than or equal to (>=) field criterion _(alias for `Field.greaterOrEqual`)_
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the greater than or equal to comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function GE(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return self::greaterOrEqual($fieldName, $value, $paramName);
    }

    /**
     * Create a less than (<) field criterion
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the less than comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function less(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return new self($fieldName, Op::Less, $value, $paramName);
    }

    /**
     * Create a less than (<) field criterion _(alias for `Field.less`)_
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the less than comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function LT(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return self::less($fieldName, $value, $paramName);
    }

    /**
     * Create a less than or equal to (<=) field criterion
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the less than or equal to comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function lessOrEqual(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return new self($fieldName, Op::LessOrEqual, $value, $paramName);
    }

    /**
     * Create a less than or equal to (<=) field criterion _(alias for `Field.lessOrEqual`)_
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the less than or equal to comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function LE(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return self::lessOrEqual($fieldName, $value, $paramName);
    }

    /**
     * Create a not equals (<>) field criterion
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the not equals comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function notEqual(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return new self($fieldName, Op::NotEqual, $value, $paramName);
    }

    /**
     * Create a not equals (<>) field criterion _(alias for `Field.notEqual`)_
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $value The value for the not equals comparison
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function NE(string $fieldName, mixed $value, string $paramName = ''): self
    {
        return self::notEqual($fieldName, $value, $paramName);
    }

    /**
     * Create a BETWEEN field criterion
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $minValue The lower value for range
     * @param mixed $maxValue The upper value for the range
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function between(string $fieldName, mixed $minValue, mixed $maxValue, string $paramName = ''): self
    {
        return new self($fieldName, Op::Between, [$minValue, $maxValue], $paramName);
    }

    /**
     * Create a BETWEEN field criterion _(alias for `Field.between`)_
     *
     * @param string $fieldName The name of the field against which the value will be compared
     * @param mixed $minValue The lower value for range
     * @param mixed $maxValue The upper value for the range
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function BT(string $fieldName, mixed $minValue, mixed $maxValue, string $paramName = ''): self
    {
        return self::between($fieldName, $minValue, $maxValue, $paramName);
    }

    /**
     * Create an IN field criterion
     *
     * @param string $fieldName The name of the field against which the values will be compared
     * @param mixed[] $values The potential matching values for the field
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function in(string $fieldName, array $values, string $paramName = ''): self
    {
        return new self($fieldName, Op::In, $values, $paramName);
    }

    /**
     * Create an IN ARRAY field criterion
     *
     * @param string $fieldName The name of the field against which the values will be compared
     * @param string $tableName The table name where this field is located
     * @param mixed[] $values The potential matching values for the field
     * @param string $paramName The name of the parameter to which this should be bound (optional; generated if blank)
     * @return self The field with the requested criterion
     */
    public static function inArray(string $fieldName, string $tableName, array $values, string $paramName = ''): self
    {
        return new self($fieldName, Op::InArray, ['table' => $tableName, 'values' => $values], $paramName);
    }

    /**
     * Create an exists (IS NOT NULL) field criterion
     *
     * @param string $fieldName The name of the field for which existence will be checked
     * @return self The field with the requested criterion
     */
    public static function exists(string $fieldName): self
    {
        return new self($fieldName, Op::Exists, '', '');
    }

    /**
     * Create an exists (IS NOT NULL) field criterion _(alias for `Field.exists`)_
     *
     * @param string $fieldName The name of the field for which existence will be checked
     * @return self The field with the requested criterion
     */
    public static function EX(string $fieldName): self
    {
        return self::exists($fieldName);
    }

    /**
     * Create a not exists (IS NULL) field criterion
     *
     * @param string $fieldName The name of the field for which non-existence will be checked
     * @return self The field with the requested criterion
     */
    public static function notExists(string $fieldName): self
    {
        return new self($fieldName, Op::NotExists, '', '');
    }

    /**
     * Create a not exists (IS NULL) field criterion _(alias for `Field.notExists`)_
     *
     * @param string $fieldName The name of the field for which non-existence will be checked
     * @return self The field with the requested criterion
     */
    public static function NEX(string $fieldName): self
    {
        return self::notExists($fieldName);
    }

    /**
     * Create a named fields (used for creating fields for ORDER BY clauses)
     *
     * Prepend the field name with 'n:' to treat the field as a number; prepend the field name with 'i:' to perform
     * a case-insensitive ordering.
     *
     * @param string $name The name of the field, plus any direction for the ordering
     * @return self
     */
    public static function named(string $name): self
    {
        return new self($name, Op::Equal, '', '');
    }
}