<?php

/**
 * League.Uri (https://uri.thephpleague.com)
 *
 * (c) Ignace Nyamagana Butera <nyamsprod@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

declare(strict_types=1);

namespace League\Uri\Components;

use BackedEnum;
use Countable;
use IteratorAggregate;
use League\Uri\Components\FragmentDirectives\DirectiveString;
use League\Uri\Contracts\Conditionable;
use League\Uri\Contracts\FragmentDirective;
use League\Uri\Contracts\FragmentInterface;
use League\Uri\Contracts\Transformable;
use League\Uri\Contracts\UriComponentInterface;
use League\Uri\Contracts\UriInterface;
use League\Uri\Encoder;
use League\Uri\Exceptions\OffsetOutOfBounds;
use League\Uri\Modifier;
use League\Uri\Uri;
use League\Uri\UriString;
use Psr\Http\Message\UriInterface as Psr7UriInterface;
use Stringable;
use Throwable;
use Traversable;
use Uri\Rfc3986\Uri as Rfc3986Uri;
use Uri\WhatWg\Url as WhatWgUrl;

use function array_count_values;
use function array_filter;
use function array_keys;
use function array_map;
use function array_slice;
use function array_values;
use function count;
use function explode;
use function implode;
use function in_array;
use function is_bool;
use function is_string;
use function sprintf;
use function str_replace;
use function strpos;
use function substr;

use const ARRAY_FILTER_USE_BOTH;

/**
 * @see https://wicg.github.io/scroll-to-text-fragment/
 *
 * @implements IteratorAggregate<int, FragmentDirective>
 */
final class FragmentDirectives implements FragmentInterface, IteratorAggregate, Countable, Conditionable, Transformable
{
    public const DELIMITER = ':~:';
    public const SEPARATOR = '&';

    /** @var list<FragmentDirective> */
    private readonly array $directives;

    public function __construct(FragmentDirective|BackedEnum|Stringable|string ...$directives)
    {
        $this->directives = array_values(array_map(self::filterDirective(...), $directives));
    }

    /**
     * Create a new instance from a Fragment.
     *
     * If no delimiter is found, an empty collection is returned
     */
    public static function fromFragment(BackedEnum|Stringable|string|null $fragment): self
    {
        if ($fragment instanceof UriComponentInterface) {
            $fragment = $fragment->value();
        }

        if ($fragment instanceof BackedEnum) {
            $fragment = $fragment->value;
        }

        if (null === $fragment) {
            return new self();
        }

        $fragment = (string) $fragment;
        $pos = strpos($fragment, self::DELIMITER);
        if (false === $pos) {
            return new self();
        }

        return self::new(substr($fragment, $pos + 3));
    }

    /**
     * Create a new instance from a string which only contains directives.
     */
    public static function new(BackedEnum|Stringable|string|null $value): self
    {
        if ($value instanceof BackedEnum) {
            $value = $value->value;
        }

        return null === $value
             ? new self()
             : new self(...explode(self::SEPARATOR, (string) $value));
    }

    private static function filterDirective(FragmentDirective|BackedEnum|Stringable|string $directive): FragmentDirective
    {
        return $directive instanceof FragmentDirective ? $directive : DirectiveString::resolve($directive);
    }

    public static function tryNew(BackedEnum|Stringable|string|null $value): ?self
    {
        try {
            return self::new($value);
        } catch (Throwable) {
            return null;
        }
    }

    /**
     *  Create a new instance from a URI string or object.
     */
    public static function fromUri(WhatWgUrl|Rfc3986Uri|BackedEnum|Stringable|string $uri): self
    {
        if ($uri instanceof Modifier) {
            $uri = $uri->unwrap();
        }

        return self::fromFragment(match (true) {
            $uri instanceof Psr7UriInterface => UriString::parse($uri)['fragment'],
            $uri instanceof Rfc3986Uri => $uri->getRawFragment(),
            $uri instanceof UriInterface, $uri instanceof WhatWgUrl => $uri->getFragment(),
            default => Uri::new($uri)->getFragment(),
        });
    }

    public function count(): int
    {
        return count($this->directives);
    }

    public function getIterator(): Traversable
    {
        yield from $this->directives;
    }

    public function __toString(): string
    {
        return $this->toString();
    }

    public function jsonSerialize(): string
    {
        return $this->toString();
    }

    public function value(): ?string
    {
        return [] === $this->directives
            ? null
            : self::DELIMITER.implode(
                self::SEPARATOR,
                array_map(fn (FragmentDirective $directive): string => $directive->toString(), $this->directives)
            );
    }

    public function toString(): string
    {
        return (string) $this->value();
    }

    public function getUriComponent(): string
    {
        $fragment = $this->value();

        return (null === $fragment ? '' : '#').$fragment;
    }

    public function decoded(): ?string
    {
        return [] === $this->directives
            ? null
            : str_replace('%20', ' ', (string) Encoder::decodeFragment($this->toString()));
    }

    /**
     * Returns the Directive at a specified offset or null if none is defined.
     *
     * Negative offsets are supported.
     */
    public function nth(int $offset): ?FragmentDirective
    {
        if ($offset < 0) {
            $offset += count($this->directives);
        }

        return $this->directives[$offset] ?? null;
    }

    /**
     * The first Directive defined on the fragment or null if none are defined.
     */
    public function first(): ?FragmentDirective
    {
        return $this->nth(0);
    }

    /**
     * The last Directive defined on the fragment or null if none are defined.
     */
    public function last(): ?FragmentDirective
    {
        return $this->nth(-1);
    }

    /**
     * Tells whether all the submitted keys are present in the collection.
     *
     * Negative offsets are supported.
     */
    public function has(int ...$offsets): bool
    {
        $nbDirectives = count($this->directives);
        foreach ($offsets as $offset) {
            if ($offset < 0) {
                $offset += $nbDirectives;
            }

            if (! isset($this->directives[$offset])) {
                return false;
            }
        }

        return [] !== $offsets;
    }

    public function isEmpty(): bool
    {
        return [] === $this->directives;
    }

    public function equals(mixed $value): bool
    {
        if (!$value instanceof BackedEnum && !$value instanceof Stringable && !is_string($value) && null !== $value) {
            return false;
        }

        if (!$value instanceof UriComponentInterface) {
            $value = self::tryNew($value);
            if (null === $value) {
                return false;
            }
        }

        return $value->getUriComponent() === $this->getUriComponent();
    }

    public function indexOf(FragmentDirective|BackedEnum|Stringable|string $directive): ?int
    {
        $directive = self::filterDirective($directive);
        foreach ($this->directives as $offset => $innerDirective) {
            if ($innerDirective->equals($directive)) {
                return $offset;
            }
        }

        return null;
    }

    public function contains(FragmentDirective|BackedEnum|Stringable|string $directive): bool
    {
        return null !== $this->indexOf($directive);
    }

    /**
     * Append one or more Directives to the fragment.
     */
    public function append(FragmentDirectives|FragmentDirective|BackedEnum|Stringable|string ...$directives): self
    {
        $items = self::implodeDirectives(...$directives);

        return [] === $items ? $this : new self(...$this->directives, ...$items);
    }

    /**
     * Prepend one or more Directives to the fragment.
     */
    public function prepend(FragmentDirectives|FragmentDirective|Stringable|string ...$directives): self
    {
        $items = self::implodeDirectives(...$directives);

        return [] === $items ? $this : new self(...$items, ...$this->directives);
    }

    /**
     * @return list<FragmentDirective|BackedEnum|Stringable|string>
     */
    private static function implodeDirectives(FragmentDirectives|FragmentDirective|BackedEnum|Stringable|string ...$directives): array
    {
        return array_merge(...array_map(fn ($d) => $d instanceof FragmentDirectives ? [...$d] : [$d], $directives));
    }

    /**
     * Removes one or more Directives by offset from the fragment.
     */
    public function remove(int ...$keys): self
    {
        if ([] === $keys) {
            return $this;
        }

        $nbDirectives = count($this->directives);
        $deletedKeys = [];
        foreach ($keys as $key) {
            $value = $key;
            if ($value < 0) {
                $value += $nbDirectives;
            }

            isset($this->directives[$value]) || throw new OffsetOutOfBounds(sprintf('The key `%s` is invalid.', $key));
            $deletedKeys[] = $value;
        }

        $deletedKeys = array_keys(array_count_values($deletedKeys));

        return $this->filter(fn (FragmentDirective $directive, int $offset): bool => !in_array($offset, $deletedKeys, true)); /* @phpstan-ignore-line */
    }

    /**
     * Slices the fragment to remove Directives portions.
     */
    public function slice(int $offset, ?int $length = null): self
    {
        $nbDirectives = count($this->directives);
        ($offset >= -$nbDirectives && $offset <= $nbDirectives) || throw new OffsetOutOfBounds(sprintf('No directive can be found at : `%s`.', $offset));
        $directives = array_slice($this->directives, $offset, $length);

        return $directives === $this->directives ? $this : new self(...$directives);
    }

    /**
     * Filter the Directives to return a new instance based on the callback.
     *
     * @param callable(FragmentDirective, int=): bool $callback
     */
    public function filter(callable $callback): self
    {
        $directives = array_filter($this->directives, $callback, ARRAY_FILTER_USE_BOTH);

        return $directives === $this->directives ? $this : new self(...$directives);
    }

    /**
     * Replace the Directive define at a specific offset.
     * Negative offsets are supported.
     *
     * If no Directive is found to the specified offset, an exception is thrown
     */
    public function replace(int $offset, FragmentDirective|BackedEnum|Stringable|string $directive): self
    {
        $currentDirective = $this->nth($offset);
        null !== $currentDirective || throw new OffsetOutOfBounds(sprintf('The key `%s` is invalid.', $offset));

        $directive = self::filterDirective($directive);
        if ($directive::class === $currentDirective::class && $currentDirective->equals($directive)) {
            return $this;
        }

        if ($offset < 0) {
            $offset += count($this->directives);
        }

        $directives = $this->directives;
        $directives[$offset] = $directive;

        return new self(...$directives);
    }

    public function when(callable|bool $condition, callable $onSuccess, ?callable $onFail = null): static
    {
        if (!is_bool($condition)) {
            $condition = $condition($this);
        }

        return match (true) {
            $condition => $onSuccess($this),
            null !== $onFail => $onFail($this),
            default => $this,
        } ?? $this;
    }

    public function transform(callable $callback): static
    {
        return $callback($this);
    }
}
