<?php

namespace App\Http\Controllers\Api;

use App\Models\FamilyGuardian;
use App\Models\Family;
use App\Models\FamilyStudent;
use App\Models\Student;
use App\Models\User;
use Illuminate\Support\Facades\DB;
use Symfony\Component\HttpFoundation\Response;

class FamilyController extends BaseApiController
{
    protected Family $family;
    protected FamilyStudent $familyStudent;
    protected FamilyGuardian $familyGuardian;
    protected Student $student;
    protected User $user;

    public function __construct()
    {
        parent::__construct();
        $this->family = model(Family::class);
        $this->familyStudent = model(FamilyStudent::class);
        $this->familyGuardian = model(FamilyGuardian::class);
        $this->student = model(Student::class);
        $this->user = model(User::class);
    }

    public function index()
    {
        $page = max(1, (int) ($this->request->getGet('page') ?? 1));
        $perPage = min(100, max(1, (int) ($this->request->getGet('per_page') ?? 20)));

        $result = $this->paginate($this->family->newQuery()->orderBy('id'), $page, $perPage);

        foreach ($result['data'] as &$family) {
            $family['students'] = $this->familyStudent
                ->where('family_id', $family['id'])
                ->findAll();
            $family['guardians'] = $this->familyGuardian
                ->where('family_id', $family['id'])
                ->findAll();
        }

        return $this->success($result, 'Families retrieved successfully');
    }

    public function show($id = null)
    {
        $family = $this->family->find($id);
        if (!$family) {
            return $this->respondError('Family not found', Response::HTTP_NOT_FOUND);
        }

        $family['students'] = $this->familyStudent->where('family_id', $id)->findAll();
        $family['guardians'] = $this->familyGuardian->where('family_id', $id)->findAll();

        return $this->success($family, 'Family retrieved successfully');
    }

    public function getByStudent($id = null)
    {
        $familyIds = $this->familyStudent->where('student_id', $id)->findColumn('family_id');
        if (empty($familyIds)) {
            return $this->success([], 'No families found for this student');
        }

        $families = $this->family->whereIn('id', $familyIds)->get();
        $payload = [];
        foreach ($families as $family) {
            $family->students = $this->familyStudent->where('family_id', $family->id)->findAll();
            $family->guardians = $this->familyGuardian->where('family_id', $family->id)->findAll();
            $payload[] = $family;
        }

        return $this->success($payload, 'Families retrieved successfully');
    }

    public function getGuardians($id = null)
    {
        $family = $this->family->find($id);
        if (!$family) {
            return $this->respondError('Family not found', Response::HTTP_NOT_FOUND);
        }

        $guardians = $this->familyGuardian->where('family_id', $id)->findAll();
        return $this->success($guardians, 'Guardians retrieved successfully');
    }

    /**
     * Get families for a student
     * GET /api/v1/families/by-student/{student_id}
     */
    public function familiesByStudent(int $studentId)
    {
        $rows = DB::table('family_students as fs')
            ->select('f.*', 'fs.is_primary_home')
            ->join('families as f', 'f.id', '=', 'fs.family_id')
            ->where('fs.student_id', $studentId)
            ->where('f.is_active', 1)
            ->orderByDesc('fs.is_primary_home')
            ->orderBy('f.household_name')
            ->get()
            ->map(fn($row) => (array) $row)
            ->toArray();

        return $this->success(['data' => $rows], 'Families retrieved successfully');
    }

    /**
     * Get guardians for a family
     * GET /api/v1/families/{family_id}/guardians
     */
    public function guardiansByFamily(int $familyId)
    {
        $rows = DB::table('family_guardians as fg')
            ->select(
                'u.id AS user_id', 'u.firstname', 'u.lastname', 'u.email',
                'fg.relation', 'fg.is_primary', 'fg.receive_emails', 'fg.receive_sms'
            )
            ->join('users as u', 'u.id', '=', 'fg.user_id')
            ->where('fg.family_id', $familyId)
            ->orderByDesc('fg.is_primary')
            ->orderBy('u.lastname')
            ->orderBy('u.firstname')
            ->get()
            ->map(fn($row) => (array) $row)
            ->toArray();

        return $this->success(['data' => $rows], 'Guardians retrieved successfully');
    }

    /**
     * Bootstrap families from existing students.parent_id
     * POST /api/v1/families/bootstrap
     */
    public function bootstrap()
    {
        // Guard: ensure required tables exist
        foreach (['families', 'family_students', 'family_guardians'] as $t) {
            if (!DB::getSchemaBuilder()->hasTable($t)) {
                return $this->respondError(
                    "Missing required table '{$t}'. Run migrations.",
                    Response::HTTP_INTERNAL_SERVER_ERROR
                );
            }
        }

        try {
            DB::beginTransaction();

            // Get all distinct primary parents from students.parent_id
            $primaryParents = DB::table('students')
                ->select('parent_id')
                ->whereNotNull('parent_id')
                ->distinct()
                ->get()
                ->map(fn($row) => (array) $row)
                ->toArray();

            $created = 0;
            $linkedStudents = 0;
            $linkedGuardians = 0;

            foreach ($primaryParents as $row) {
                $primaryUserId = (int) $row['parent_id'];
                if ($primaryUserId <= 0) continue;

                $familyId = $this->ensureFamilyForPrimaryParent($primaryUserId, $created);

                // Link all students of this primary parent
                $students = DB::table('students')
                    ->select('id')
                    ->where('parent_id', $primaryUserId)
                    ->get()
                    ->map(fn($row) => (array) $row)
                    ->toArray();

                foreach ($students as $s) {
                    $linkedStudents += $this->attachStudentToFamily((int) $s['id'], $familyId);
                }

                // Ensure primary parent is guardian on that family
                $linkedGuardians += $this->attachGuardianUser($familyId, $primaryUserId, 'primary', true, 1, 0);
            }

            DB::commit();

            return $this->success([
                'families_created' => $created,
                'students_linked' => $linkedStudents,
                'guardians_linked' => $linkedGuardians,
            ], 'Bootstrap completed successfully');
        } catch (\Throwable $e) {
            DB::rollBack();
            log_message('error', 'Family bootstrap error: ' . $e->getMessage());
            return $this->respondError('Failed to bootstrap families: ' . $e->getMessage(), Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * Attach second parent by user ID
     * POST /api/v1/families/attach-second-by-user
     */
    public function attachSecondByUser()
    {
        $data = $this->payloadData();
        $studentId = (int) ($data['student_id'] ?? 0);
        $userId = (int) ($data['user_id'] ?? 0);
        $relation = (string) ($data['relation'] ?? 'secondary');

        if (!$studentId || !$userId) {
            return $this->respondError('student_id and user_id required', Response::HTTP_BAD_REQUEST);
        }

        $familyId = $this->familyIdFromStudentPrimary($studentId);
        if (!$familyId) {
            return $this->respondError('No primary family found for this student', Response::HTTP_NOT_FOUND);
        }

        $rows = $this->attachGuardianUser($familyId, $userId, $relation, false, 1, 0);

        return $this->success([
            'attached' => $rows,
            'family_id' => $familyId,
        ], 'Guardian attached successfully');
    }

    /**
     * Attach second parent by email (creates user if needed)
     * POST /api/v1/families/attach-second-by-email
     */
    public function attachSecondByEmail()
    {
        $data = $this->payloadData();
        $studentId = (int) ($data['student_id'] ?? 0);
        $email = trim((string) ($data['email'] ?? ''));
        $first = trim((string) ($data['firstname'] ?? ''));
        $last = trim((string) ($data['lastname'] ?? ''));
        $relation = (string) ($data['relation'] ?? 'secondary');

        if (!$studentId || !$email) {
            return $this->respondError('student_id and email required', Response::HTTP_BAD_REQUEST);
        }

        $familyId = $this->familyIdFromStudentPrimary($studentId);
        if (!$familyId) {
            return $this->respondError('No primary family found for this student', Response::HTTP_NOT_FOUND);
        }

        $user = $this->user->where('email', $email)->first();
        if (!$user) {
            // Create a minimal/stub user
            $newUser = $this->user->create([
                'firstname' => $first ?: '',
                'lastname' => $last ?: '',
                'email' => $email,
                'status' => 'Active',
                'user_type' => 'secondary',
            ]);
            if (!$newUser || !isset($newUser['id'])) {
                return $this->respondError('Failed to create user', Response::HTTP_INTERNAL_SERVER_ERROR);
            }
            $userId = (int) $newUser['id'];
        } else {
            $userId = (int) $user['id'];
        }

        $rows = $this->attachGuardianUser($familyId, $userId, $relation, false, 1, 0);

        return $this->success([
            'attached' => $rows,
            'family_id' => $familyId,
            'user_id' => $userId,
        ], 'Guardian attached successfully');
    }

    /**
     * Set primary home flag for a student-family relationship
     * POST /api/v1/families/set-primary-home
     */
    public function setPrimaryHome()
    {
        $data = $this->payloadData();
        $familyId = (int) ($data['family_id'] ?? 0);
        $studentId = (int) ($data['student_id'] ?? 0);
        $flag = (int) ($data['is_primary_home'] ?? 0);

        if (!$familyId || !$studentId) {
            return $this->respondError('family_id and student_id required', Response::HTTP_BAD_REQUEST);
        }

        try {
            $this->familyStudent
                ->where(['family_id' => $familyId, 'student_id' => $studentId])
                ->update(['is_primary_home' => $flag ? 1 : 0]);

            return $this->success(null, 'Primary home flag updated successfully');
        } catch (\Throwable $e) {
            log_message('error', 'Set primary home error: ' . $e->getMessage());
            return $this->respondError('Failed to update primary home flag', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * Set guardian flags (receive_emails, is_primary, receive_sms, relation)
     * POST /api/v1/families/set-guardian-flags
     */
    public function setGuardianFlags()
    {
        $data = $this->payloadData();
        $familyId = (int) ($data['family_id'] ?? 0);
        $userId = (int) ($data['user_id'] ?? 0);

        if (!$familyId || !$userId) {
            return $this->respondError('family_id and user_id required', Response::HTTP_BAD_REQUEST);
        }

        $updateData = [];
        foreach (['receive_emails', 'is_primary', 'receive_sms', 'relation'] as $k) {
            if (isset($data[$k])) {
                $val = $data[$k];
                $updateData[$k] = in_array($k, ['receive_emails', 'is_primary', 'receive_sms'])
                    ? (int) $val
                    : (string) $val;
            }
        }

        if (empty($updateData)) {
            return $this->respondError('No flags provided', Response::HTTP_BAD_REQUEST);
        }

        try {
            $this->familyGuardian
                ->where(['family_id' => $familyId, 'user_id' => $userId])
                ->update($updateData);

            return $this->success(null, 'Guardian flags updated successfully');
        } catch (\Throwable $e) {
            log_message('error', 'Set guardian flags error: ' . $e->getMessage());
            return $this->respondError('Failed to update guardian flags', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * Unlink a guardian from a family
     * POST /api/v1/families/unlink-guardian
     */
    public function unlinkGuardian()
    {
        $data = $this->payloadData();
        $familyId = (int) ($data['family_id'] ?? 0);
        $userId = (int) ($data['user_id'] ?? 0);

        if (!$familyId || !$userId) {
            return $this->respondError('family_id and user_id required', Response::HTTP_BAD_REQUEST);
        }

        try {
            $this->familyGuardian
                ->where(['family_id' => $familyId, 'user_id' => $userId])
                ->delete();

            return $this->success(null, 'Guardian unlinked successfully');
        } catch (\Throwable $e) {
            log_message('error', 'Unlink guardian error: ' . $e->getMessage());
            return $this->respondError('Failed to unlink guardian', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * Unlink a student from a family
     * POST /api/v1/families/unlink-student
     */
    public function unlinkStudent()
    {
        $data = $this->payloadData();
        $familyId = (int) ($data['family_id'] ?? 0);
        $studentId = (int) ($data['student_id'] ?? 0);

        if (!$familyId || !$studentId) {
            return $this->respondError('family_id and student_id required', Response::HTTP_BAD_REQUEST);
        }

        try {
            $this->familyStudent
                ->where(['family_id' => $familyId, 'student_id' => $studentId])
                ->delete();

            return $this->success(null, 'Student unlinked successfully');
        } catch (\Throwable $e) {
            log_message('error', 'Unlink student error: ' . $e->getMessage());
            return $this->respondError('Failed to unlink student', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * Import second parents from legacy 'parents' table
     * POST /api/v1/families/import-second-parents
     */
    public function importSecondParentsFromLegacy()
    {
        $L = [
            'table' => 'parents',
            'firstparent_id' => 'firstparent_id',
            'second_user_id' => 'secondparent_id',
            'second_email' => 'secondparent_email',
            'second_firstname' => 'secondparent_firstname',
            'second_lastname' => 'secondparent_lastname',
        ];

        if (!DB::getSchemaBuilder()->hasTable($L['table'])) {
            return $this->respondError("Legacy table '{$L['table']}' not found", Response::HTTP_NOT_FOUND);
        }

        foreach (['families', 'family_students', 'family_guardians'] as $t) {
            if (!DB::getSchemaBuilder()->hasTable($t)) {
                return $this->respondError(
                    "Missing required table '{$t}'. Run migrations.",
                    Response::HTTP_INTERNAL_SERVER_ERROR
                );
            }
        }

        try {
            $rows = DB::table($L['table'])
                ->select(
                    DB::raw("{$L['firstparent_id']} AS first_id"),
                    DB::raw("{$L['second_user_id']} AS second_id"),
                    DB::raw("{$L['second_email']} AS email"),
                    DB::raw("{$L['second_firstname']} AS firstname"),
                    DB::raw("{$L['second_lastname']} AS lastname")
                )
                ->where(function ($query) use ($L) {
                    $query->where($L['second_user_id'], '!=', 0)
                        ->orWhere($L['second_email'], '!=', '');
                })
                ->get()
                ->map(fn($row) => (array) $row)
                ->toArray();

            $createdUsers = 0;
            $linked = 0;
            $skipped = 0;

            foreach ($rows as $r) {
                $firstId = (int) ($r['first_id'] ?? 0);
                $secondId = (int) ($r['second_id'] ?? 0);
                $email = trim((string) ($r['email'] ?? ''));

                if (!$firstId || (!$secondId && $email === '')) {
                    $skipped++;
                    continue;
                }

                // Ensure/find family by primary parent
                $code = 'FAM-' . $firstId;
                $fam = $this->family->where('family_code', $code)->first();
                if ($fam) {
                    $familyId = (int) $fam['id'];
                } else {
                    $tmp = 0; // counter sink
                    $familyId = $this->ensureFamilyForPrimaryParent($firstId, $tmp);
                }

                // Resolve/create user
                $userId = 0;
                if ($secondId > 0) {
                    $userId = $secondId;
                } else {
                    $user = $this->user->where('email', $email)->first();
                    if (!$user) {
                        $newUser = $this->user->create([
                            'firstname' => $r['firstname'] ?? '',
                            'lastname' => $r['lastname'] ?? '',
                            'email' => $email,
                            'status' => 'Active',
                            'user_type' => 'secondary',
                        ]);
                        if ($newUser && isset($newUser['id'])) {
                            $userId = (int) $newUser['id'];
                            $createdUsers++;
                        } else {
                            $userId = 0;
                        }
                    } else {
                        $userId = (int) $user['id'];
                    }
                }

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

                // Ensure all students for this primary parent are linked to this family
                $stuRows = DB::table('students')
                    ->select('id')
                    ->where('parent_id', $firstId)
                    ->get()
                    ->map(fn($row) => (array) $row)
                    ->toArray();

                foreach ($stuRows as $sr) {
                    $sid = (int) ($sr['id'] ?? 0);
                    if ($sid > 0) {
                        $this->attachStudentToFamily($sid, $familyId);
                    }
                }

                // Link as guardian (idempotent)
                $linked += $this->attachGuardianUser($familyId, $userId, 'guardian', false, 1, 0);
            }

            return $this->success([
                'created_users' => $createdUsers,
                'guardians_linked' => $linked,
                'skipped' => $skipped,
                'total_source' => count($rows),
            ], 'Legacy import completed successfully');
        } catch (\Throwable $e) {
            log_message('error', 'Import second parents error: ' . $e->getMessage());
            return $this->respondError('Failed to import second parents: ' . $e->getMessage(), Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /* =========================================================
     * Private helpers
     * =======================================================*/

    /**
     * Ensure there is exactly one family per primary parent (users.id)
     * Returns $familyId and increments $createdCounter by reference if newly created.
     */
    protected function ensureFamilyForPrimaryParent(int $primaryUserId, int &$createdCounter): int
    {
        $code = 'FAM-' . $primaryUserId;
        $row = $this->family->where('family_code', $code)->first();
        if ($row) {
            return (int) $row['id'];
        }

        $family = $this->family->create([
            'family_code' => $code,
            'household_name' => 'Family of User ' . $primaryUserId,
            'is_active' => 1,
        ]);

        if ($family && isset($family['id'])) {
            $createdCounter++;
            return (int) $family['id'];
        }

        // If create failed, try to find it again (race condition)
        $row = $this->family->where('family_code', $code)->first();
        if ($row) {
            return (int) $row['id'];
        }

        throw new \Exception('Failed to create family for primary parent ' . $primaryUserId);
    }

    /**
     * Attach a student to a family (idempotent; returns rows affected >0 if inserted)
     */
    protected function attachStudentToFamily(int $studentId, int $familyId): int
    {
        // Check if already exists
        $exists = $this->familyStudent
            ->where('family_id', $familyId)
            ->where('student_id', $studentId)
            ->first();

        if ($exists) {
            return 0;
        }

        // Insert
        $result = $this->familyStudent->create([
            'family_id' => $familyId,
            'student_id' => $studentId,
            'is_primary_home' => 1,
        ]);

        return ($result && isset($result['id'])) ? 1 : 0;
    }

    /**
     * Attach a guardian user to family (idempotent)
     */
    protected function attachGuardianUser(
        int $familyId,
        int $userId,
        string $relation = 'primary',
        bool $isPrimary = false,
        int $receiveEmails = 1,
        int $receiveSms = 0
    ): int {
        // Check if already exists
        $exists = $this->familyGuardian
            ->where('family_id', $familyId)
            ->where('user_id', $userId)
            ->first();

        if ($exists) {
            return 0;
        }

        // Insert
        $result = $this->familyGuardian->create([
            'family_id' => $familyId,
            'user_id' => $userId,
            'relation' => $relation,
            'is_primary' => $isPrimary ? 1 : 0,
            'receive_emails' => $receiveEmails,
            'receive_sms' => $receiveSms,
        ]);

        return ($result && isset($result['id'])) ? 1 : 0;
    }

    /**
     * Find the "primary" family for a student = family created from parent_id
     */
    protected function familyIdFromStudentPrimary(int $studentId): ?int
    {
        // Get primary parent id for the student
        $st = $this->student->select('parent_id')->find($studentId);
        if (!$st || empty($st['parent_id'])) {
            return null;
        }

        // The canonical family uses code FAM-{parent_id}
        $code = 'FAM-' . (int) $st['parent_id'];
        $row = $this->family->select('id')->where('family_code', $code)->first();
        if ($row) {
            return (int) $row['id'];
        }

        // If not found, fall back to any family linked already
        $row = DB::table('family_students')
            ->select('family_id')
            ->where('student_id', $studentId)
            ->orderByDesc('is_primary_home')
            ->first();

        return $row ? (int) $row->family_id : null;
    }
}