<?php

declare(strict_types=1);

namespace App\Controllers;

use App\Models\Customer;
use App\Repositories\CustomerAuditRepository;
use App\Repositories\CustomerRepository;
use App\Repositories\CustomerTypeRepository;
use App\Services\FileImportService;
use App\ViewModels\CustomerViewModel;
use Core\Controller;
use Core\Request;
use Core\Response;

class CustomerController extends Controller
{
    public function index(): Response
    {
        $request = Request::capture();
        $model = new CustomerViewModel();
        $model->saved   = $request->input('saved') === '1';
        $model->deleted = $request->input('deleted') === '1';

        return $this->view('customers.index', [
            'model'     => $model,
            'pageTitle' => $model->title,
        ]);
    }

    public function data(): Response
    {
        $rows = $this->repo()->allWithType();

        $data = array_map(static function (array $row): array {
            $attrValues = !empty($row['attribute_values'])
                ? (json_decode((string) $row['attribute_values'], true) ?? [])
                : [];
            $customerTypeAttributes = !empty($row['customer_type_attributes'])
                ? (json_decode((string) $row['customer_type_attributes'], true) ?? [])
                : [];

            $summary = implode(', ', array_map(
                static fn($k, $v) => "{$k}: {$v}",
                array_keys($attrValues),
                array_values($attrValues)
            ));

            return [
                'id'                       => (int)    $row['id'],
                'customer_type_id'         => (int)    $row['customer_type_id'],
                'customer_type_name'       => (string) $row['customer_type_name'],
                'customer_type_attributes' => $customerTypeAttributes,
                'attribute_values'         => $attrValues,
                'attributes_summary'       => $summary,
                'created_at'               => (string) $row['created_at'],
            ];
        }, $rows);

        return $this->json($data);
    }

    public function create(): Response
    {
        $model = new CustomerViewModel();
        $model->title         = 'New Customer';
        $model->customerTypes = $this->loadCustomerTypes();

        return $this->view('customers.create', [
            'model'     => $model,
            'pageTitle' => $model->title,
        ]);
    }

    public function store(): Response
    {
        $request = Request::capture();
        $model   = new CustomerViewModel();
        $model->title         = 'New Customer';
        $model->customerTypes = $this->loadCustomerTypes();

        [$form, $errors] = $this->validateForm($request, $model->customerTypes);

        if (!empty($errors)) {
            $model->form   = $form;
            $model->errors = $errors;

            return $this->view('customers.create', [
                'model'     => $model,
                'pageTitle' => $model->title,
            ]);
        }

        $encodedValues = json_encode($form['attribute_values'], JSON_THROW_ON_ERROR | JSON_UNESCAPED_UNICODE);
        $duplicate     = $this->repo()->findDuplicate((int) $form['customer_type_id'], $encodedValues);

        if ($duplicate !== null) {
            $model->form           = $form;
            $model->errors['_duplicate'] = [
                'A customer with these exact values already exists: <a href="/customers/' . (int) $duplicate['id'] . '/edit">Customer #' . (int) $duplicate['id'] . ' (' . htmlspecialchars((string) $duplicate['customer_type_name'], ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8') . ')</a>.',
            ];

            return $this->view('customers.create', [
                'model'     => $model,
                'pageTitle' => $model->title,
            ]);
        }

        $customer                  = new Customer();
        $customer->customerTypeId  = (int) $form['customer_type_id'];
        $customer->attributeValues = $form['attribute_values'];

        $this->repo()->create($customer);

        $inserted = $this->repo()->findLatestByType($customer->customerTypeId);
        if ($inserted !== null) {
            $this->auditRepo()->log((int) $inserted['id'], 'I', $this->toAuditFields($inserted), $this->currentUsername());
        }

        return $this->redirect('/customers?saved=1');
    }

    public function edit(string $id): Response
    {
        $row = $this->repo()->findWithType((int) $id);

        if ($row === null) {
            return $this->redirect('/customers');
        }

        $storedValues = !empty($row['attribute_values'])
            ? (json_decode((string) $row['attribute_values'], true) ?? [])
            : [];

        $model = new CustomerViewModel();
        $model->title         = 'Edit Customer';
        $model->customer      = $row;
        $model->saved         = Request::capture()->input('saved') === '1';
        $model->customerTypes = $this->loadCustomerTypes();
        $model->form          = [
            'customer_type_id' => (int) $row['customer_type_id'],
            'attribute_values' => $storedValues,
        ];

        return $this->view('customers.edit', [
            'model'     => $model,
            'pageTitle' => $model->title,
        ]);
    }

    public function update(string $id): Response
    {
        $before = $this->repo()->findWithType((int) $id);

        if ($before === null) {
            return $this->redirect('/customers');
        }

        $request = Request::capture();
        $model   = new CustomerViewModel();
        $model->title         = 'Edit Customer';
        $model->customer      = $before;
        $model->customerTypes = $this->loadCustomerTypes();

        [$form, $errors] = $this->validateForm($request, $model->customerTypes);

        if (!empty($errors)) {
            $model->form   = $form;
            $model->errors = $errors;

            return $this->view('customers.edit', [
                'model'     => $model,
                'pageTitle' => $model->title,
            ]);
        }

        $encodedValues = json_encode($form['attribute_values'], JSON_THROW_ON_ERROR | JSON_UNESCAPED_UNICODE);
        $duplicate     = $this->repo()->findDuplicate((int) $form['customer_type_id'], $encodedValues, (int) $id);

        if ($duplicate !== null) {
            $model->form           = $form;
            $model->errors['_duplicate'] = [
                'These values are identical to an existing customer: <a href="/customers/' . (int) $duplicate['id'] . '/edit">Customer #' . (int) $duplicate['id'] . ' (' . htmlspecialchars((string) $duplicate['customer_type_name'], ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8') . ')</a>.',
            ];

            return $this->view('customers.edit', [
                'model'     => $model,
                'pageTitle' => $model->title,
            ]);
        }

        $customer                  = new Customer();
        $customer->id              = (int) $id;
        $customer->customerTypeId  = (int) $form['customer_type_id'];
        $customer->attributeValues = $form['attribute_values'];

        $this->repo()->update($customer);

        $after = $this->repo()->findWithType((int) $id);
        $this->auditRepo()->log((int) $id, 'U', [
            'before' => $this->toAuditFields($before),
            'after'  => $this->toAuditFields($after ?? []),
        ], $this->currentUsername());

        return $this->redirect('/customers/' . $id . '/edit?saved=1');
    }

    public function destroy(string $id): Response
    {
        $row = $this->repo()->findWithType((int) $id);

        if ($row !== null) {
            $this->repo()->delete((int) $id);
            $this->auditRepo()->log((int) $row['id'], 'D', $this->toAuditFields($row), $this->currentUsername());
        }

        return $this->redirect('/customers?deleted=1');
    }

    // ── CSV Import ────────────────────────────────────────────────────────────

    public function importUpload(): Response
    {
        $request = Request::capture();
        if (!verify_csrf_token((string) $request->input('_token', ''))) {
            return Response::json(['error' => 'Session expired. Please refresh.'], 419);
        }

        $upload = $_FILES['csv_file'] ?? null;
        if ($upload === null || ($upload['error'] ?? UPLOAD_ERR_NO_FILE) === UPLOAD_ERR_NO_FILE) {
            return Response::json(['error' => 'No file was uploaded.'], 422);
        }

        try {
            $service  = $this->fileImport();
            $filename = $service->store($upload);
            $data     = $service->rows($filename, '0');

            return Response::json(['temp_name' => $filename, 'headers' => $data['headers']]);
        } catch (\Throwable $e) {
            return Response::json(['error' => $e->getMessage()], 422);
        }
    }

    public function importPreview(): Response
    {
        $request = Request::capture();
        if (!verify_csrf_token((string) $request->input('_token', ''))) {
            return Response::json(['error' => 'Session expired. Please refresh.'], 419);
        }

        $customerTypeId = (int) $request->input('customer_type_id', 0);
        if ($customerTypeId === 0) {
            return Response::json(['error' => 'Customer type is required.'], 422);
        }

        $tempName = basename((string) $request->input('temp_name', ''));
        if ($tempName === '') {
            return Response::json(['error' => 'No file uploaded.'], 422);
        }

        $mapping = (array) ($request->input('mapping') ?? []);

        try {
            $data  = $this->fileImport()->rows($tempName, '0');
            $rows  = [];
            $stats = ['total' => 0, 'ok' => 0, 'duplicate' => 0, 'empty' => 0];

            foreach ($data['rows'] as $i => $csvRow) {
                $stats['total']++;
                $attributeValues = $this->applyMapping($mapping, $csvRow);

                $hasValue = false;
                foreach ($attributeValues as $v) {
                    if ($v !== '') { $hasValue = true; break; }
                }

                if (!$hasValue) {
                    $stats['empty']++;
                    $rows[] = ['index' => $i + 1, 'status' => 'empty', 'values' => $attributeValues, 'message' => 'Row is empty'];
                    continue;
                }

                $encodedValues = json_encode($attributeValues, JSON_THROW_ON_ERROR | JSON_UNESCAPED_UNICODE);
                $duplicate     = $this->repo()->findDuplicate($customerTypeId, $encodedValues);

                if ($duplicate !== null) {
                    $stats['duplicate']++;
                    $rows[] = [
                        'index'   => $i + 1,
                        'status'  => 'duplicate',
                        'values'  => $attributeValues,
                        'message' => 'Duplicate of Customer #' . (int) $duplicate['id'],
                    ];
                } else {
                    $stats['ok']++;
                    $rows[] = ['index' => $i + 1, 'status' => 'ok', 'values' => $attributeValues, 'message' => null];
                }
            }

            return Response::json(['rows' => $rows, 'stats' => $stats]);
        } catch (\Throwable $e) {
            return Response::json(['error' => $e->getMessage()], 422);
        }
    }

    public function importApprove(): Response
    {
        $request = Request::capture();
        if (!verify_csrf_token((string) $request->input('_token', ''))) {
            return Response::json(['error' => 'Session expired. Please refresh.'], 419);
        }

        $customerTypeId = (int) $request->input('customer_type_id', 0);
        if ($customerTypeId === 0) {
            return Response::json(['error' => 'Customer type is required.'], 422);
        }

        $tempName = basename((string) $request->input('temp_name', ''));
        if ($tempName === '') {
            return Response::json(['error' => 'No file uploaded.'], 422);
        }

        $mapping = (array) ($request->input('mapping') ?? []);

        try {
            $service  = $this->fileImport();
            $data     = $service->rows($tempName, '0');
            $inserted = 0;
            $skipped  = 0;
            $errors   = [];

            foreach ($data['rows'] as $i => $csvRow) {
                $attributeValues = $this->applyMapping($mapping, $csvRow);

                $hasValue = false;
                foreach ($attributeValues as $v) {
                    if ($v !== '') { $hasValue = true; break; }
                }

                if (!$hasValue) {
                    $skipped++;
                    continue;
                }

                try {
                    $customer                  = new Customer();
                    $customer->customerTypeId  = $customerTypeId;
                    $customer->attributeValues = $attributeValues;
                    $this->repo()->create($customer);

                    $insertedRow = $this->repo()->findLatestByType($customerTypeId);
                    if ($insertedRow !== null) {
                        $this->auditRepo()->log(
                            (int) $insertedRow['id'],
                            'I',
                            $this->toAuditFields($insertedRow),
                            $this->currentUsername()
                        );
                    }

                    $inserted++;
                } catch (\Throwable $e) {
                    $errors[] = 'Row ' . ($i + 1) . ': ' . $e->getMessage();
                }
            }

            $service->delete($tempName);

            return Response::json(['inserted' => $inserted, 'skipped' => $skipped, 'errors' => $errors]);
        } catch (\Throwable $e) {
            return Response::json(['error' => $e->getMessage()], 422);
        }
    }

    // ── Helpers ───────────────────────────────────────────────────────────────

    private function loadCustomerTypes(): array
    {
        return array_map(static function (array $type): array {
            return [
                'id'         => (int)    $type['id'],
                'name'       => (string) $type['name'],
                'attributes' => json_decode((string) ($type['attributes'] ?? '[]'), true) ?? [],
            ];
        }, $this->ctRepo()->allOrderedByName());
    }

    private function attributesForType(int $typeId, array $types): array
    {
        foreach ($types as $type) {
            if ($type['id'] === $typeId) return $type['attributes'];
        }
        return [];
    }

    private function validateForm(Request $request, array $customerTypes): array
    {
        $customerTypeId  = (int) $request->input('customer_type_id', 0);
        $submittedValues = (array) ($request->input('attribute_values') ?? []);
        $errors          = [];

        if (!verify_csrf_token((string) $request->input('_token', ''))) {
            $errors['_token'][] = 'Your form session expired. Please refresh and try again.';
        }

        if ($customerTypeId === 0) {
            $errors['customer_type_id'][] = 'Please select a customer type.';
        }

        $typeAttributes  = $this->attributesForType($customerTypeId, $customerTypes);
        $attributeValues = [];
        foreach ($typeAttributes as $attr) {
            $attributeValues[$attr['name']] = trim((string) ($submittedValues[$attr['name']] ?? ''));
        }

        return [
            ['customer_type_id' => $customerTypeId, 'attribute_values' => $attributeValues],
            $errors,
        ];
    }

    private function toAuditFields(array $row): array
    {
        $attrValues = [];
        if (!empty($row['attribute_values'])) {
            $raw        = $row['attribute_values'];
            $attrValues = is_string($raw) ? (json_decode($raw, true) ?? []) : (array) $raw;
        }

        return [
            'customer_type_id'   => (int)    ($row['customer_type_id']   ?? 0),
            'customer_type_name' => (string) ($row['customer_type_name'] ?? ''),
            'attribute_values'   => $attrValues,
            'created_at'         => (string) ($row['created_at']         ?? ''),
            'updated_at'         => (string) ($row['updated_at']         ?? ''),
        ];
    }

    private function currentUsername(): string
    {
        return auth()->user()?->username ?? 'system';
    }

    private function applyMapping(array $mapping, array $csvRow): array
    {
        $attributeValues = [];
        foreach ($mapping as $attrName => $csvColumn) {
            $csvColumn = trim((string) $csvColumn);
            if ($csvColumn === '') continue;
            $attributeValues[trim((string) $attrName)] = trim((string) ($csvRow[$csvColumn] ?? ''));
        }
        return $attributeValues;
    }

    private function fileImport(): FileImportService
    {
        return new FileImportService();
    }

    private function repo(): CustomerRepository
    {
        return new CustomerRepository(database());
    }

    private function auditRepo(): CustomerAuditRepository
    {
        return new CustomerAuditRepository(database());
    }

    private function ctRepo(): CustomerTypeRepository
    {
        return new CustomerTypeRepository(database());
    }
}