<?php

namespace App\Http\Controllers;

use App\Models\Role;
use App\Models\User;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Str;
use Illuminate\Validation\Rule;

class UserController extends Controller
{
    public function index(): JsonResponse
    {
        $users = User::query()
            ->with(['roles', 'rank'])
            ->orderBy('id')
            ->get()
            ->map(fn (User $user) => [
                'id' => $user->id,
                'name' => $user->name,
                'email' => $user->email,
                'avatar_url' => $this->resolveAvatarUrl($user),
                'location' => $user->location,
                'rank' => $user->rank ? [
                    'id' => $user->rank->id,
                    'name' => $user->rank->name,
                    'color' => $user->rank->color,
                ] : null,
                'group_color' => $this->resolveGroupColor($user),
                'roles' => $user->roles->pluck('name')->values(),
            ]);

        return response()->json($users);
    }

    public function me(Request $request): JsonResponse
    {
        $user = $request->user();

        if (!$user) {
            return response()->json(['message' => 'Unauthenticated.'], 401);
        }

        return response()->json([
            'id' => $user->id,
            'name' => $user->name,
            'email' => $user->email,
            'avatar_url' => $this->resolveAvatarUrl($user),
            'location' => $user->location,
            'rank' => $user->rank ? [
                'id' => $user->rank->id,
                'name' => $user->rank->name,
                'color' => $user->rank->color,
            ] : null,
            'group_color' => $this->resolveGroupColor($user),
            'roles' => $user->roles()->pluck('name')->values(),
        ]);
    }

    public function profile(User $user): JsonResponse
    {
        return response()->json([
            'id' => $user->id,
            'name' => $user->name,
            'avatar_url' => $this->resolveAvatarUrl($user),
            'location' => $user->location,
            'rank' => $user->rank ? [
                'id' => $user->rank->id,
                'name' => $user->rank->name,
                'color' => $user->rank->color,
            ] : null,
            'group_color' => $this->resolveGroupColor($user),
            'created_at' => $user->created_at?->toIso8601String(),
        ]);
    }

    public function updateMe(Request $request): JsonResponse
    {
        $user = $request->user();
        if (!$user) {
            return response()->json(['message' => 'Unauthenticated.'], 401);
        }

        $data = $request->validate([
            'location' => ['nullable', 'string', 'max:255'],
        ]);

        $location = isset($data['location']) ? trim($data['location']) : null;
        if ($location === '') {
            $location = null;
        }

        $user->forceFill([
            'location' => $location,
        ])->save();

        $user->loadMissing('rank');

        return response()->json([
            'id' => $user->id,
            'name' => $user->name,
            'email' => $user->email,
            'avatar_url' => $this->resolveAvatarUrl($user),
            'location' => $user->location,
            'rank' => $user->rank ? [
                'id' => $user->rank->id,
                'name' => $user->rank->name,
                'color' => $user->rank->color,
            ] : null,
            'group_color' => $this->resolveGroupColor($user),
            'roles' => $user->roles()->pluck('name')->values(),
        ]);
    }

    public function updateRank(Request $request, User $user): JsonResponse
    {
        $actor = $request->user();
        if (!$actor || !$actor->roles()->where('name', 'ROLE_ADMIN')->exists()) {
            return response()->json(['message' => 'Forbidden'], 403);
        }
        if ($this->isFounder($user) && !$this->isFounder($actor)) {
            return response()->json(['message' => 'Forbidden'], 403);
        }

        $data = $request->validate([
            'rank_id' => ['nullable', 'exists:ranks,id'],
        ]);

        $user->rank_id = $data['rank_id'] ?? null;
        $user->save();

        $user->loadMissing('rank');

        return response()->json([
            'id' => $user->id,
            'rank' => $user->rank ? [
                'id' => $user->rank->id,
                'name' => $user->rank->name,
                'color' => $user->rank->color,
            ] : null,
            'group_color' => $this->resolveGroupColor($user),
        ]);
    }

    public function update(Request $request, User $user): JsonResponse
    {
        $actor = $request->user();
        if (!$actor || !$actor->roles()->where('name', 'ROLE_ADMIN')->exists()) {
            return response()->json(['message' => 'Forbidden'], 403);
        }
        if ($this->isFounder($user) && !$this->isFounder($actor)) {
            return response()->json(['message' => 'Forbidden'], 403);
        }

        $data = $request->validate([
            'name' => ['required', 'string', 'max:255'],
            'email' => [
                'required',
                'string',
                'email',
                'max:255',
                Rule::unique('users', 'email')->ignore($user->id),
            ],
            'rank_id' => ['nullable', 'exists:ranks,id'],
            'roles' => ['nullable', 'array'],
            'roles.*' => ['string', 'exists:roles,name'],
        ]);

        if (array_key_exists('roles', $data) && !$this->isFounder($actor)) {
            $requested = collect($data['roles'] ?? [])
                ->map(fn ($name) => $this->normalizeRoleName($name));
            if ($requested->contains('ROLE_FOUNDER')) {
                return response()->json(['message' => 'Forbidden'], 403);
            }
        }

        $nameCanonical = Str::lower(trim($data['name']));
        $nameConflict = User::query()
            ->where('id', '!=', $user->id)
            ->where('name_canonical', $nameCanonical)
            ->exists();

        if ($nameConflict) {
            return response()->json(['message' => 'Name already exists.'], 422);
        }

        if ($data['email'] !== $user->email) {
            $user->email_verified_at = null;
        }

        $user->forceFill([
            'name' => $data['name'],
            'name_canonical' => $nameCanonical,
            'email' => $data['email'],
            'rank_id' => $data['rank_id'] ?? null,
        ])->save();

        if (array_key_exists('roles', $data)) {
            $roleNames = collect($data['roles'] ?? [])
                ->map(fn ($name) => $this->normalizeRoleName($name))
                ->unique()
                ->values()
                ->all();
            $roleIds = Role::query()
                ->whereIn('name', $roleNames)
                ->pluck('id')
                ->all();
            $user->roles()->sync($roleIds);
        }

        $user->loadMissing('rank');

        return response()->json([
            'id' => $user->id,
            'name' => $user->name,
            'email' => $user->email,
            'avatar_url' => $this->resolveAvatarUrl($user),
            'rank' => $user->rank ? [
                'id' => $user->rank->id,
                'name' => $user->rank->name,
                'color' => $user->rank->color,
            ] : null,
            'group_color' => $this->resolveGroupColor($user),
            'roles' => $user->roles()->pluck('name')->values(),
        ]);
    }

    private function resolveAvatarUrl(User $user): ?string
    {
        if (!$user->avatar_path) {
            return null;
        }

        return Storage::url($user->avatar_path);
    }

    private function resolveGroupColor(User $user): ?string
    {
        $user->loadMissing('roles');
        $roles = $user->roles;
        if (!$roles) {
            return null;
        }

        foreach ($roles->sortBy('name') as $role) {
            if (!empty($role->color)) {
                return $role->color;
            }
        }

        return null;
    }

    private function normalizeRoleName(string $value): string
    {
        $raw = strtoupper(trim($value));
        $raw = preg_replace('/\s+/', '_', $raw);
        $raw = preg_replace('/[^A-Z0-9_]/', '_', $raw);
        $raw = preg_replace('/_+/', '_', $raw);
        $raw = trim($raw, '_');
        if ($raw === '') {
            return 'ROLE_';
        }
        if (str_starts_with($raw, 'ROLE_')) {
            return $raw;
        }
        return "ROLE_{$raw}";
    }

    private function isFounder(User $user): bool
    {
        return $user->roles()->where('name', 'ROLE_FOUNDER')->exists();
    }
}