<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Collection;

use App\Models\User;

return new class extends Migration
{
    /**
     * Run the migrations.
     */
    public function up(): void
    {
        // 1. Create new column discord_id
        Schema::table('users', function (Blueprint $table) {
            $table->unsignedBigInteger('discord_id')->nullable()->after('id');
        });

        // 2. Migrate Discord Users IDs
        DB::table('users')
            ->where('id', '>', 10000)
            ->update(['discord_id' => DB::raw('id')]);

        // 3. Temporary new auto increment column
        Schema::table('users', function (Blueprint $table) {
            $table->unsignedBigInteger('new_id')->first();
        });

        // 3.5 Manually count (cursed)
        $counter = 1;
        foreach(User::orderBy('id')->get() as $user) {
            $user->new_id = $counter;
            $user->save();
            $counter++;
        }

        // 4. Drop foreign keys
        $this->dropForeignKeys();

        // 5. Fix ID's in other tables
        $this->updateUserIDsInOtherTables();

        // 6. Remove old ID
        Schema::table('users', function (Blueprint $table) {
            $table->bigInteger('id')->unsigned()->change();
            $table->dropPrimary('id');
            $table->dropColumn('id');
        });

        // 7. Rename new_id to id
        Schema::table('users', function (Blueprint $table) {
            $table->renameColumn('new_id', 'id');
            $table->unsignedBigInteger('id')->autoIncrement()->primary()->change();
        });

        // 8. Recreate foreign key constraints
        $this->addForeignKeys();
    }

    /**
     * Drop Foreign Keys referencing the user id
     */
    private function dropForeignKeys(): void
    {
        Schema::table('markable_likes', function (Blueprint $table) {
            $table->dropForeign(['user_id']);
        });

        Schema::table('watched', function (Blueprint $table) {
            $table->dropForeign(['user_id']);
        });

        Schema::table('discord_access_tokens', function (Blueprint $table) {
            $table->dropForeign(['user_id']);
        });

        // Our Schema does include a foreign key, for whatever reason it doesn't exist in the first palce
        // Schema::table('user_downloads', function (Blueprint $table) {
        //     $table->dropForeign(['user_id']);
        // });
    }

    /**
     * Tables to fix the IDs:
     *  - comments ['commenter_id']
     *  - discord_access_tokens ['user_id']
     *  - markable_likes ['user_id']
     *  - notifications ['notifiable_id']
     *  - playlists ['user_id']
     *  - user_downloads ['user_id']
     *  - watched ['user_id']
     */
    private function updateUserIDsInOtherTables(): void
    {

        DB::table('users')->orderBy('id')->chunk(100, function (Collection $users) {
            foreach ($users as $user) {
                DB::table('comments')
                    ->where('commenter_id', $user->id)
                    ->update(['commenter_id' => $user->new_id]);

                DB::table('discord_access_tokens')
                    ->where('user_id', $user->id)
                    ->update(['user_id' => $user->new_id]);

                DB::table('markable_likes')
                    ->where('user_id', $user->id)
                    ->update(['user_id' => $user->new_id]);

                DB::table('notifications')
                    ->where('notifiable_id', $user->id)
                    ->update(['notifiable_id' => $user->new_id]);

                DB::table('playlists')
                    ->where('user_id', $user->id)
                    ->update(['user_id' => $user->new_id]);

                DB::table('user_downloads')
                    ->where('user_id', $user->id)
                    ->update(['user_id' => $user->new_id]);

                DB::table('watched')
                    ->where('user_id', $user->id)
                    ->update(['user_id' => $user->new_id]);
            }
        });
    }

    /**
     * Re-Add Foreign Keys to tables which we dropped previously
     */
    private function addForeignKeys(): void
    {
        Schema::table('markable_likes', function (Blueprint $table) {
            $table->unsignedBigInteger('user_id')->references('id')->on('users')->onDelete('cascade')->change();
        });

        Schema::table('watched', function (Blueprint $table) {
            $table->unsignedBigInteger('user_id')->references('id')->on('users')->onDelete('cascade')->change();
        });

        Schema::table('discord_access_tokens', function (Blueprint $table) {
            $table->unsignedBigInteger('user_id')->references('id')->on('users')->onDelete('cascade')->change();
        });

        Schema::table('user_downloads', function (Blueprint $table) {
            $table->unsignedBigInteger('user_id')->references('id')->on('users')->onDelete('cascade')->change();
        });
    }
};