<?php

namespace App\Controllers\Administrator;

use App\Controllers\BaseController;
use App\Models\FinancialAidEstimateModel;
use App\Models\FinancialAidRequestModel;
use App\Models\InvoiceModel;
use App\Models\StudentModel;
use App\Models\UserModel;
use InvalidArgumentException;
use Throwable;

class FinancialAidController extends BaseController
{
    public function index()
    {
        $schoolYear = $this->request->getGet('school_year');
        $model = new FinancialAidRequestModel();
        $builder = $model->orderBy('created_at', 'DESC');
        if (is_string($schoolYear) && trim($schoolYear) !== '') {
            $builder->where('school_year', trim($schoolYear));
        }

        $requests = $builder->findAll();
        $parentIds = array_values(array_unique(array_filter(array_map('intval', array_column($requests, 'parent_id')))));
        $parents = [];
        if ($parentIds !== []) {
            foreach ((new UserModel())->select('id, firstname, lastname, email')->whereIn('id', $parentIds)->findAll() as $parent) {
                $parents[(int) $parent['id']] = $parent;
            }
        }

        return view('administrator/financial_aid_queue', [
            'requests' => $requests,
            'parents' => $parents,
            'schoolYear' => is_string($schoolYear) ? trim($schoolYear) : '',
        ]);
    }

    public function show(int $id)
    {
        $request = (new FinancialAidRequestModel())->find($id);
        if ($request === null) {
            return redirect()->to('/administrator/financial-aid')->with('error', 'Financial aid request was not found.');
        }

        $parent = (new UserModel())->find((int) $request['parent_id']);
        $studentIds = json_decode((string) ($request['student_ids_json'] ?? '[]'), true);
        $studentIds = is_array($studentIds) ? array_map('intval', $studentIds) : [];
        $students = $studentIds !== []
            ? (new StudentModel())->whereIn('id', $studentIds)->findAll()
            : [];

        $schoolYear = (string) ($request['school_year'] ?? '');
        $invoiceBalance = $this->invoiceBalanceForParent((int) ($request['parent_id'] ?? 0), $schoolYear);
        $householdSize = max(1, (int) ($request['household_size'] ?? 1));
        $householdIncome = (float) ($request['household_income'] ?? 0);
        $requestedAmount = (float) ($request['requested_amount'] ?? 0);
        $estimateModel = new FinancialAidEstimateModel();
        $estimatedAid = $estimateModel->estimatedAid($invoiceBalance, $householdSize, $householdIncome);
        $finalRebate = $estimateModel->finalRebate($invoiceBalance, $householdSize, $householdIncome, $requestedAmount);

        return view('administrator/financial_aid_review', [
            'requestRow' => $request,
            'parent' => $parent,
            'students' => $students,
            'schoolYear' => $schoolYear,
            'invoiceBalance' => $invoiceBalance,
            'estimatedAid' => $estimatedAid,
            'finalRebate' => $finalRebate,
        ]);
    }

    public function estimate(int $id)
    {
        $request = (new FinancialAidRequestModel())->find($id);
        if ($request === null) {
            return $this->response->setStatusCode(404)->setJSON(['error' => 'Financial aid request was not found.']);
        }

        $householdIncomeRaw = trim((string) $this->request->getPost('household_income'));
        $householdSizeRaw = (int) $this->request->getPost('household_size');
        $schoolYear = (string) ($request['school_year'] ?? '');
        $invoiceBalance = $this->invoiceBalanceForParent((int) ($request['parent_id'] ?? 0), $schoolYear);

        if ($householdIncomeRaw === '' || ! is_numeric($householdIncomeRaw) || (float) $householdIncomeRaw < 0) {
            return $this->response->setStatusCode(422)->setJSON(['error' => 'Enter a valid household income.']);
        }
        if ($householdSizeRaw < 1) {
            return $this->response->setStatusCode(422)->setJSON(['error' => 'Household size must be at least 1.']);
        }

        try {
            $estimateModel = new FinancialAidEstimateModel();
            $householdIncome = round((float) $householdIncomeRaw, 2);
            $estimatedAid = $estimateModel->estimatedAid($invoiceBalance, $householdSizeRaw, $householdIncome);
            $finalRebate = $estimateModel->finalRebate(
                $invoiceBalance,
                $householdSizeRaw,
                $householdIncome,
                (float) ($request['requested_amount'] ?? 0)
            );

            return $this->response->setJSON([
                'invoice_balance' => $invoiceBalance,
                'estimated_aid' => $estimatedAid,
                'final_rebate' => $finalRebate,
                'csrf_token' => csrf_token(),
                'csrf_hash' => csrf_hash(),
            ]);
        } catch (InvalidArgumentException $e) {
            return $this->response->setStatusCode(422)->setJSON(['error' => $e->getMessage()]);
        }
    }

    public function approve(int $id)
    {
        try {
            $model = new FinancialAidRequestModel();
            $request = $model->find($id);
            if ($request === null) {
                return redirect()->to('/administrator/financial-aid')->with('error', 'Financial aid request was not found.');
            }
            if (! in_array((string) ($request['status'] ?? ''), ['submitted', 'under_review'], true)) {
                return redirect()->back()->with('error', 'Only open requests can be approved.');
            }

            $amount = $this->approvalAmount($request);
            $note = trim((string) $this->request->getPost('admin_note'));
            service('financialAid')->applyApprovedAmount($request, $amount, (int) session()->get('user_id'), $note);

            return redirect()->to('/administrator/financial-aid')->with('success', 'Financial aid was approved and applied to the invoice.');
        } catch (Throwable $e) {
            return redirect()->back()->withInput()->with('error', $e->getMessage());
        }
    }

    public function deny(int $id)
    {
        $model = new FinancialAidRequestModel();
        $request = $model->find($id);
        if ($request === null) {
            return redirect()->to('/administrator/financial-aid')->with('error', 'Financial aid request was not found.');
        }
        if (! in_array((string) ($request['status'] ?? ''), ['submitted', 'under_review'], true)) {
            return redirect()->back()->with('error', 'Only open requests can be denied.');
        }

        $note = trim((string) $this->request->getPost('admin_note'));
        if ($note === '') {
            return redirect()->back()->with('error', 'A denial note is required.');
        }

        $model->update($id, [
            'status' => 'denied',
            'admin_note' => $note,
            'reviewed_by' => (int) session()->get('user_id'),
            'reviewed_at' => date('Y-m-d H:i:s'),
        ]);

        return redirect()->to('/administrator/financial-aid')->with('success', 'Financial aid request was denied.');
    }

    private function approvalAmount(array $request): float
    {
        $postedAmount = trim((string) $this->request->getPost('admin_amount'));
        if ($postedAmount !== '') {
            return (float) $postedAmount;
        }

        return (float) ($request['requested_amount'] ?? 0);
    }

    private function invoiceBalanceForParent(int $parentId, string $schoolYear): float
    {
        if ($parentId <= 0 || $schoolYear === '') {
            return 0.0;
        }

        $invoice = (new InvoiceModel())
            ->where('parent_id', $parentId)
            ->where('school_year', $schoolYear)
            ->orderBy('id', 'DESC')
            ->first();

        if ($invoice === null) {
            return 0.0;
        }

        return round((float) ($invoice['balance'] ?? 0), 2);
    }
}