<?php

namespace App\Services\PembiayaanOnline;

use App\Cawangan;
use App\ModalOnline;
use App\RequestModalOnline;
use Carbon\Carbon;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;

class ModalOnlineService
{
    /**
     * @return array{ok:bool,status:int,payload:mixed,mysql?:string}
     */
    public function resolveMysql($kodcaw)
    {
        $cawangan = Cawangan::on('mysql7')->where('kodcaw', '=', $kodcaw)->first();

        if (!$cawangan) {
            return [
                'ok' => false,
                'status' => 404,
                'payload' => ['message' => 'Cawangan tidak dijumpai'],
            ];
        }

        return [
            'ok' => true,
            'status' => 200,
            'payload' => null,
            'mysql' => $cawangan['mysql'],
        ];
    }

    protected function todayDate()
    {
        return Carbon::now()->toDateString();
    }

    protected function findPending($kodcaw)
    {
        return RequestModalOnline::on('mysql7')
            ->where('kodcaw', $kodcaw)
            ->where('status', 'PENDING')
            ->first();
    }

    protected function pendingPayload($pending)
    {
        return $pending ? $pending->toArray() : null;
    }

    protected function missingSnapshot($kodcaw, $tarikh, $pending = null)
    {
        return [
            'tarikh' => $tarikh,
            'kodcaw' => $kodcaw,
            'had' => 0.00,
            'digunakan' => 0.00,
            'baki' => 0.00,
            'tambah' => 0.00,
            'kurang' => 0.00,
            'ditutup' => 0,
            'missing' => true,
            'pending_request' => $this->pendingPayload($pending),
        ];
    }

    protected function recalcBaki($modal)
    {
        $modal->baki = round(
            (float) $modal->had + (float) $modal->tambah - (float) $modal->kurang - (float) $modal->digunakan,
            2
        );
    }

    /**
     * Get today's modal_online row. Does not create — PC must request had from Operasi.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function get($kodcaw)
    {
        $resolved = $this->resolveMysql($kodcaw);
        if (!$resolved['ok']) {
            return $resolved;
        }

        $mysql = $resolved['mysql'];
        $tarikh = $this->todayDate();
        $pending = $this->findPending($kodcaw);

        $modal = ModalOnline::on($mysql)
            ->where('kodcaw', $kodcaw)
            ->where('tarikh', $tarikh)
            ->first();

        if (!$modal) {
            return [
                'ok' => true,
                'status' => 200,
                'payload' => $this->missingSnapshot($kodcaw, $tarikh, $pending),
            ];
        }

        $payload = $modal->toArray();
        $payload['missing'] = false;
        $payload['pending_request'] = $this->pendingPayload($pending);

        return [
            'ok' => true,
            'status' => 200,
            'payload' => $payload,
        ];
    }

    /**
     * @deprecated Use get(). Kept so existing callers do not auto-seed RM100k.
     */
    public function getOrCreate($kodcaw)
    {
        return $this->get($kodcaw);
    }

    /**
     * Reserve amount inside an existing branch DB connection (caller may wrap in transaction).
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function reserveAmountOnConnection($mysql, $kodcaw, $amaun, $tarikh = null)
    {
        $amaun = round((float) $amaun, 2);
        if ($amaun <= 0) {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'Amaun tidak sah'],
            ];
        }

        $tarikh = $tarikh ?: Carbon::now()->toDateString();

        $modal = ModalOnline::on($mysql)
            ->where('kodcaw', $kodcaw)
            ->where('tarikh', $tarikh)
            ->lockForUpdate()
            ->first();

        if (!$modal) {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => [
                    'message' => 'Modal online belum diwujudkan. Sila mohon had daripada Operasi terlebih dahulu.',
                    'missing' => true,
                ],
            ];
        }

        if ((int) ($modal->ditutup ?? 0) === 1) {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => [
                    'message' => 'Modal online hari ini sudah ditutup (EOD)',
                    'modal_online' => $modal,
                ],
            ];
        }

        if ((float) $modal->baki < $amaun) {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => [
                    'message' => 'Baki modal online tidak mencukupi',
                    'baki' => (float) $modal->baki,
                    'amaun' => $amaun,
                ],
            ];
        }

        $modal->digunakan = round((float) $modal->digunakan + $amaun, 2);
        $modal->baki = round(
            (float) $modal->had + (float) $modal->tambah - (float) $modal->kurang - (float) $modal->digunakan,
            2
        );
        $modal->save();

        return [
            'ok' => true,
            'status' => 200,
            'payload' => $modal,
        ];
    }

    /**
     * Reserve amount from today's online float (transactional).
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function reserve($kodcaw, $amaun)
    {
        $resolved = $this->resolveMysql($kodcaw);
        if (!$resolved['ok']) {
            return $resolved;
        }

        $mysql = $resolved['mysql'];
        $amaun = round((float) $amaun, 2);

        if ($amaun <= 0) {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'Amaun tidak sah'],
            ];
        }

        try {
            return DB::connection($mysql)->transaction(function () use ($mysql, $kodcaw, $amaun) {
                return $this->reserveAmountOnConnection($mysql, $kodcaw, $amaun);
            });
        } catch (\Throwable $e) {
            Log::error('ModalOnline reserve failed: ' . $e->getMessage());
            return [
                'ok' => false,
                'status' => 500,
                'payload' => ['message' => 'Gagal reserve modal online'],
            ];
        }
    }

    /**
     * Had is no longer auto-seeded. Returns how many branches already have a row today.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function initiate($zone = 'all')
    {
        $current = $this->todayDate();

        if ($zone == 'all') {
            $cawanganAll = Cawangan::on('mysql7')->get();
        } else {
            $cawanganAll = Cawangan::on('mysql7')->where('zone', $zone)->get();
        }

        $existing = 0;
        $missing = 0;

        foreach ($cawanganAll as $cawangan) {
            try {
                $exists = ModalOnline::on($cawangan['mysql'])
                    ->where('kodcaw', $cawangan['kodcaw'])
                    ->where('tarikh', $current)
                    ->exists();

                if ($exists) {
                    $existing++;
                } else {
                    $missing++;
                }
            } catch (\Throwable $e) {
                Log::warning('initiate modal_online skip ' . $cawangan['kodcaw'] . ': ' . $e->getMessage());
            }
        }

        return [
            'ok' => true,
            'status' => 200,
            'payload' => [
                'tarikh' => $current,
                'created' => 0,
                'existing' => $existing,
                'missing' => $missing,
                'message' => 'Modal online tidak di-initiate automatik. PC perlu mohon had daripada Operasi.',
            ],
        ];
    }

    /**
     * PC request opening had (or extra top-up) from Operasi.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function requestTopUp($kodcaw, $amaun, $dimohonOleh, $nota = null)
    {
        $resolved = $this->resolveMysql($kodcaw);
        if (!$resolved['ok']) {
            return $resolved;
        }
        $mysql = $resolved['mysql'];

        $amaun = round((float) $amaun, 2);
        $dimohonOleh = trim((string) $dimohonOleh);

        if ($amaun <= 0) {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'Amaun tidak sah'],
            ];
        }
        if ($dimohonOleh === '') {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'dimohon_oleh diperlukan'],
            ];
        }

        $tarikh = $this->todayDate();
        $pending = $this->findPending($kodcaw);

        if ($pending) {
            return [
                'ok' => false,
                'status' => 409,
                'payload' => [
                    'message' => 'Masih ada permohonan modal online PENDING untuk cawangan ini',
                    'request' => $pending,
                ],
            ];
        }

        $modal = ModalOnline::on($mysql)
            ->where('kodcaw', $kodcaw)
            ->where('tarikh', $tarikh)
            ->first();

        if ($modal && (int) ($modal->ditutup ?? 0) === 1) {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => [
                    'message' => 'Modal online hari ini sudah ditutup (EOD). Tidak boleh mohon.',
                    'modal_online' => $modal,
                ],
            ];
        }

        $jenis = $modal ? 'TOPUP' : 'HAD';

        $request = RequestModalOnline::on('mysql7')->create([
            'kodcaw' => $kodcaw,
            'tarikh' => $tarikh,
            'amaun' => $amaun,
            'dimohon_oleh' => $dimohonOleh,
            'status' => 'PENDING',
            'nota' => $nota,
        ]);

        return [
            'ok' => true,
            'status' => 201,
            'payload' => [
                'request' => $request,
                'jenis' => $jenis,
                'modal_online' => $modal ?: $this->missingSnapshot($kodcaw, $tarikh, $request),
            ],
        ];
    }

    /**
     * List top-up requests.
     * For PC: pass kodcaw. For Operasi: omit kodcaw (all branches).
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function listTopUpRequests($kodcaw = null, $status = null, $tarikh = null)
    {
        $query = RequestModalOnline::on('mysql7')->newQuery();

        if ($kodcaw) {
            $query->where('kodcaw', $kodcaw);
        }
        if ($status) {
            $query->where('status', $status);
        }
        if ($tarikh) {
            $query->where('tarikh', $tarikh);
        }

        $rows = $query->orderBy('id', 'desc')->get();

        $cawMap = [];
        if (!$kodcaw) {
            foreach (Cawangan::on('mysql7')->get() as $caw) {
                $cawMap[$caw->kodcaw] = $caw->nama_cawangan;
            }
        }

        $data = [];
        foreach ($rows as $row) {
            $item = $row->toArray();
            if (!$kodcaw) {
                $item['cawangan_nama'] = $cawMap[$row->kodcaw] ?? null;
            }
            $data[] = $item;
        }

        return [
            'ok' => true,
            'status' => 200,
            'payload' => [
                'bilangan' => count($data),
                'data' => $data,
            ],
        ];
    }

    /**
     * Operasi approve: first request of the day sets had; later requests add tambah.
     * Optional $amaunOverride lets operasi lulus a different amount than dimohon.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function approveTopUp($requestId, $diluluskanOleh, $nota = null, $expectedKodcaw = null, $amaunOverride = null)
    {
        $diluluskanOleh = trim((string) $diluluskanOleh);
        if ($diluluskanOleh === '') {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'diluluskan_oleh diperlukan'],
            ];
        }

        $req = RequestModalOnline::on('mysql7')->where('id', $requestId)->first();
        if (!$req) {
            return [
                'ok' => false,
                'status' => 404,
                'payload' => ['message' => 'Permohonan tidak dijumpai'],
            ];
        }

        if ($expectedKodcaw && $req->kodcaw !== $expectedKodcaw) {
            return [
                'ok' => false,
                'status' => 404,
                'payload' => ['message' => 'Permohonan tidak dijumpai'],
            ];
        }

        if ($req->status !== 'PENDING') {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => [
                    'message' => 'Hanya permohonan PENDING boleh diluluskan',
                    'status' => $req->status,
                ],
            ];
        }

        $kodcaw = $req->kodcaw;
        $resolved = $this->resolveMysql($kodcaw);
        if (!$resolved['ok']) {
            return $resolved;
        }
        $mysql = $resolved['mysql'];
        $amaunDimohon = round((float) $req->amaun, 2);
        $amaun = $amaunDimohon;
        if ($amaunOverride !== null && $amaunOverride !== '') {
            $amaun = round((float) $amaunOverride, 2);
            if ($amaun <= 0) {
                return [
                    'ok' => false,
                    'status' => 422,
                    'payload' => ['message' => 'Amaun diluluskan tidak sah'],
                ];
            }
        }
        $tarikh = $this->todayDate();

        try {
            $applied = DB::connection($mysql)->transaction(function () use ($mysql, $kodcaw, $tarikh, $amaun) {
                $modal = ModalOnline::on($mysql)
                    ->where('kodcaw', $kodcaw)
                    ->where('tarikh', $tarikh)
                    ->lockForUpdate()
                    ->first();

                $jenis = 'TOPUP';

                if (!$modal) {
                    $modal = ModalOnline::on($mysql)->create([
                        'tarikh' => $tarikh,
                        'kodcaw' => $kodcaw,
                        'had' => $amaun,
                        'digunakan' => 0.00,
                        'baki' => $amaun,
                        'tambah' => 0.00,
                        'kurang' => 0.00,
                        'ditutup' => 0,
                    ]);
                    $modal = ModalOnline::on($mysql)
                        ->where('id', $modal->id)
                        ->lockForUpdate()
                        ->first();
                    $jenis = 'HAD';
                } else {
                    if ((int) ($modal->ditutup ?? 0) === 1) {
                        throw new \RuntimeException('MODAL_ONLINE_CLOSED');
                    }

                    $modal->tambah = round((float) $modal->tambah + $amaun, 2);
                    $this->recalcBaki($modal);
                    $modal->save();
                }

                return ['modal' => $modal, 'jenis' => $jenis];
            });

            $modal = $applied['modal'];
            $jenis = $applied['jenis'];

            $req->status = 'APPROVED';
            $req->diluluskan_oleh = $diluluskanOleh;
            $req->amaun = $amaun;

            $notes = [];
            if (abs($amaun - $amaunDimohon) >= 0.01) {
                $notes[] = 'Amaun dimohon RM ' . number_format($amaunDimohon, 2)
                    . ', diluluskan RM ' . number_format($amaun, 2);
            }
            if ($nota !== null && trim((string) $nota) !== '') {
                $notes[] = trim((string) $nota);
            }
            if ($notes) {
                $existing = trim((string) $req->nota);
                $req->nota = $existing === ''
                    ? implode(' | ', $notes)
                    : $existing . ' | ' . implode(' | ', $notes);
            }
            $req->save();

            return [
                'ok' => true,
                'status' => 200,
                'payload' => [
                    'request' => $req->fresh(),
                    'jenis' => $jenis,
                    'modal_online' => $modal,
                ],
            ];
        } catch (\Throwable $e) {
            if ($e->getMessage() === 'MODAL_ONLINE_CLOSED') {
                return [
                    'ok' => false,
                    'status' => 422,
                    'payload' => ['message' => 'Modal online hari ini sudah ditutup (EOD). Tidak boleh lulus permohonan.'],
                ];
            }
            Log::error('approveTopUp failed: ' . $e->getMessage());
            return [
                'ok' => false,
                'status' => 500,
                'payload' => ['message' => 'Gagal lulus permohonan modal online'],
            ];
        }
    }

    /**
     * Operasi reject top-up request.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function rejectTopUp($requestId, $diluluskanOleh, $nota = null, $expectedKodcaw = null)
    {
        $diluluskanOleh = trim((string) $diluluskanOleh);
        if ($diluluskanOleh === '') {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'diluluskan_oleh diperlukan'],
            ];
        }

        $req = RequestModalOnline::on('mysql7')->where('id', $requestId)->first();
        if (!$req) {
            return [
                'ok' => false,
                'status' => 404,
                'payload' => ['message' => 'Permohonan tidak dijumpai'],
            ];
        }

        if ($expectedKodcaw && $req->kodcaw !== $expectedKodcaw) {
            return [
                'ok' => false,
                'status' => 404,
                'payload' => ['message' => 'Permohonan tidak dijumpai'],
            ];
        }

        if ($req->status !== 'PENDING') {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => [
                    'message' => 'Hanya permohonan PENDING boleh ditolak',
                    'status' => $req->status,
                ],
            ];
        }

        $req->status = 'REJECTED';
        $req->diluluskan_oleh = $diluluskanOleh;
        if ($nota !== null && trim((string) $nota) !== '') {
            $req->nota = trim(
                trim((string) $req->nota) === ''
                    ? (string) $nota
                    : $req->nota . ' | ' . $nota
            );
        }
        $req->save();

        return [
            'ok' => true,
            'status' => 200,
            'payload' => ['request' => $req],
        ];
    }

    /**
     * EOD close for one branch: return unused baki via kurang, mark ditutup.
     * Also auto-rejects PENDING top-up requests for the branch.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function close($kodcaw, $ditutupOleh)
    {
        $resolved = $this->resolveMysql($kodcaw);
        if (!$resolved['ok']) {
            return $resolved;
        }
        $mysql = $resolved['mysql'];

        $ditutupOleh = trim((string) $ditutupOleh);
        if ($ditutupOleh === '') {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'ditutup_oleh diperlukan'],
            ];
        }

        $tarikh = Carbon::now()->toDateString();
        $now = Carbon::now();

        try {
            $result = DB::connection($mysql)->transaction(function () use ($mysql, $kodcaw, $tarikh, $ditutupOleh, $now) {
                $modal = ModalOnline::on($mysql)
                    ->where('kodcaw', $kodcaw)
                    ->where('tarikh', $tarikh)
                    ->lockForUpdate()
                    ->first();

                if (!$modal) {
                    return [
                        'ok' => false,
                        'status' => 404,
                        'payload' => [
                            'message' => 'Tiada modal online hari ini untuk ditutup. Teller belum mohon / PC belum lulus had.',
                            'missing' => true,
                        ],
                    ];
                }

                if ((int) ($modal->ditutup ?? 0) === 1) {
                    return [
                        'ok' => false,
                        'status' => 409,
                        'payload' => [
                            'message' => 'Modal online sudah ditutup untuk hari ini',
                            'modal_online' => $modal,
                        ],
                    ];
                }

                $unused = round((float) $modal->baki, 2);
                $modal->kurang = round((float) $modal->kurang + $unused, 2);
                $modal->baki = round(
                    (float) $modal->had + (float) $modal->tambah - (float) $modal->kurang - (float) $modal->digunakan,
                    2
                );
                $modal->ditutup = 1;
                $modal->ditutup_oleh = $ditutupOleh;
                $modal->ditutup_at = $now;
                $modal->save();

                return [
                    'ok' => true,
                    'status' => 200,
                    'payload' => [
                        'modal_online' => $modal,
                        'dikembalikan' => $unused,
                    ],
                ];
            });

            if (!$result['ok']) {
                return $result;
            }

            $pendingRejected = RequestModalOnline::on('mysql7')
                ->where('kodcaw', $kodcaw)
                ->where('status', 'PENDING')
                ->get();

            foreach ($pendingRejected as $req) {
                $req->status = 'REJECTED';
                $req->diluluskan_oleh = $ditutupOleh;
                $tag = 'Auto reject: EOD close';
                $req->nota = trim((string) $req->nota) === ''
                    ? $tag
                    : trim($req->nota) . ' | ' . $tag;
                $req->save();
            }

            $result['payload']['pending_topup_ditolak'] = $pendingRejected->count();
            return $result;
        } catch (\Throwable $e) {
            Log::error('modal online close failed: ' . $e->getMessage());
            return [
                'ok' => false,
                'status' => 500,
                'payload' => ['message' => 'Gagal tutup modal online'],
            ];
        }
    }

    /**
     * Operasi: list today's modal_online across branches.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function listToday($zone = 'all', $tarikh = null)
    {
        $tarikh = $tarikh ?: Carbon::now()->toDateString();

        if ($zone == 'all') {
            $cawanganAll = Cawangan::on('mysql7')->get();
        } else {
            $cawanganAll = Cawangan::on('mysql7')->where('zone', $zone)->get();
        }

        $rows = [];
        foreach ($cawanganAll as $cawangan) {
            try {
                $modal = ModalOnline::on($cawangan['mysql'])
                    ->where('kodcaw', $cawangan['kodcaw'])
                    ->where('tarikh', $tarikh)
                    ->first();

                $row = $modal ? $modal->toArray() : [
                    'tarikh' => $tarikh,
                    'kodcaw' => $cawangan['kodcaw'],
                    'had' => 0,
                    'digunakan' => 0,
                    'baki' => 0,
                    'tambah' => 0,
                    'kurang' => 0,
                    'ditutup' => 0,
                    'missing' => true,
                ];
                $row['cawangan_nama'] = $cawangan->nama_cawangan;
                $row['missing'] = empty($modal);
                $rows[] = $row;
            } catch (\Throwable $e) {
                Log::warning('listToday modal_online skip ' . $cawangan['kodcaw'] . ': ' . $e->getMessage());
            }
        }

        usort($rows, function ($a, $b) {
            return strcmp((string) ($a['kodcaw'] ?? ''), (string) ($b['kodcaw'] ?? ''));
        });

        $open = 0;
        $closed = 0;
        $missing = 0;
        foreach ($rows as $row) {
            if (!empty($row['missing'])) {
                $missing++;
            } elseif ((int) ($row['ditutup'] ?? 0) === 1) {
                $closed++;
            } else {
                $open++;
            }
        }

        return [
            'ok' => true,
            'status' => 200,
            'payload' => [
                'tarikh' => $tarikh,
                'bilangan' => count($rows),
                'open' => $open,
                'closed' => $closed,
                'missing' => $missing,
                'data' => $rows,
            ],
        ];
    }

    /**
     * Operasi bulk EOD close for open branches today.
     *
     * @return array{ok:bool,status:int,payload:mixed}
     */
    public function closeAll($ditutupOleh, $zone = 'all')
    {
        $ditutupOleh = trim((string) $ditutupOleh);
        if ($ditutupOleh === '') {
            return [
                'ok' => false,
                'status' => 422,
                'payload' => ['message' => 'ditutup_oleh diperlukan'],
            ];
        }

        $list = $this->listToday($zone);
        $closed = 0;
        $skipped = 0;
        $failed = [];

        foreach ($list['payload']['data'] as $row) {
            if (!empty($row['missing']) || (int) ($row['ditutup'] ?? 0) === 1) {
                $skipped++;
                continue;
            }
            $res = $this->close($row['kodcaw'], $ditutupOleh);
            if ($res['ok']) {
                $closed++;
            } else {
                $failed[] = [
                    'kodcaw' => $row['kodcaw'],
                    'message' => $res['payload']['message'] ?? 'gagal',
                ];
            }
        }

        return [
            'ok' => true,
            'status' => 200,
            'payload' => [
                'closed' => $closed,
                'skipped' => $skipped,
                'failed' => $failed,
            ],
        ];
    }
}