<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Support\Facades\DB;

class Income extends Model
{
    use HasFactory;

    // 收入類型常數
    const TYPE_MEMBERSHIP_FEE = 'membership_fee';   // 會費收入
    const TYPE_ENTRANCE_FEE = 'entrance_fee';       // 入會費收入
    const TYPE_DONATION = 'donation';               // 捐款收入
    const TYPE_ACTIVITY = 'activity';               // 活動收入
    const TYPE_GRANT = 'grant';                     // 補助收入
    const TYPE_INTEREST = 'interest';               // 利息收入
    const TYPE_OTHER = 'other';                     // 其他收入

    // 狀態常數
    const STATUS_PENDING = 'pending';               // 待確認
    const STATUS_CONFIRMED = 'confirmed';           // 已確認
    const STATUS_CANCELLED = 'cancelled';           // 已取消

    // 付款方式常數
    const PAYMENT_METHOD_CASH = 'cash';
    const PAYMENT_METHOD_BANK_TRANSFER = 'bank_transfer';
    const PAYMENT_METHOD_CHECK = 'check';

    protected $fillable = [
        'income_number',
        'title',
        'description',
        'income_date',
        'amount',
        'income_type',
        'chart_of_account_id',
        'payment_method',
        'bank_account',
        'payer_name',
        'receipt_number',
        'transaction_reference',
        'attachment_path',
        'member_id',
        'status',
        'recorded_by_cashier_id',
        'recorded_at',
        'confirmed_by_accountant_id',
        'confirmed_at',
        'cashier_ledger_entry_id',
        'notes',
    ];

    protected $casts = [
        'income_date' => 'date',
        'amount' => 'decimal:2',
        'recorded_at' => 'datetime',
        'confirmed_at' => 'datetime',
    ];

    /**
     * Boot 方法 - 自動產生收入編號
     */
    protected static function boot()
    {
        parent::boot();

        static::creating(function ($income) {
            if (empty($income->income_number)) {
                $income->income_number = self::generateIncomeNumber();
            }
            if (empty($income->recorded_at)) {
                $income->recorded_at = now();
            }
        });
    }

    /**
     * 產生收入編號 INC-2025-0001
     */
    public static function generateIncomeNumber(): string
    {
        $year = date('Y');
        $prefix = "INC-{$year}-";

        $lastIncome = self::where('income_number', 'like', "{$prefix}%")
            ->orderBy('income_number', 'desc')
            ->first();

        if ($lastIncome) {
            $lastNumber = (int) substr($lastIncome->income_number, -4);
            $newNumber = $lastNumber + 1;
        } else {
            $newNumber = 1;
        }

        return $prefix . str_pad($newNumber, 4, '0', STR_PAD_LEFT);
    }

    // ========== 關聯 ==========

    /**
     * 會計科目
     */
    public function chartOfAccount(): BelongsTo
    {
        return $this->belongsTo(ChartOfAccount::class);
    }

    /**
     * 關聯會員
     */
    public function member(): BelongsTo
    {
        return $this->belongsTo(Member::class);
    }

    /**
     * 記錄的出納人員
     */
    public function recordedByCashier(): BelongsTo
    {
        return $this->belongsTo(User::class, 'recorded_by_cashier_id');
    }

    /**
     * 確認的會計人員
     */
    public function confirmedByAccountant(): BelongsTo
    {
        return $this->belongsTo(User::class, 'confirmed_by_accountant_id');
    }

    /**
     * 關聯的出納日記帳
     */
    public function cashierLedgerEntry(): BelongsTo
    {
        return $this->belongsTo(CashierLedgerEntry::class);
    }

    /**
     * 會計分錄
     */
    public function accountingEntries(): HasMany
    {
        return $this->hasMany(AccountingEntry::class);
    }

    // ========== 狀態查詢 ==========

    /**
     * 是否待確認
     */
    public function isPending(): bool
    {
        return $this->status === self::STATUS_PENDING;
    }

    /**
     * 是否已確認
     */
    public function isConfirmed(): bool
    {
        return $this->status === self::STATUS_CONFIRMED;
    }

    /**
     * 是否已取消
     */
    public function isCancelled(): bool
    {
        return $this->status === self::STATUS_CANCELLED;
    }

    /**
     * 是否可以被會計確認
     */
    public function canBeConfirmed(): bool
    {
        return $this->status === self::STATUS_PENDING;
    }

    /**
     * 是否可以被取消
     */
    public function canBeCancelled(): bool
    {
        return $this->status === self::STATUS_PENDING;
    }

    // ========== 業務方法 ==========

    /**
     * 會計確認收入
     */
    public function confirmByAccountant(User $accountant): void
    {
        if (!$this->canBeConfirmed()) {
            throw new \Exception('此收入無法確認');
        }

        DB::transaction(function () use ($accountant) {
            // 1. 更新收入狀態
            $this->update([
                'status' => self::STATUS_CONFIRMED,
                'confirmed_by_accountant_id' => $accountant->id,
                'confirmed_at' => now(),
            ]);

            // 2. 產生出納日記帳記錄
            $ledgerEntry = $this->createCashierLedgerEntry();

            // 3. 產生會計分錄
            $this->generateAccountingEntries();
        });
    }

    /**
     * 取消收入
     */
    public function cancel(): void
    {
        if (!$this->canBeCancelled()) {
            throw new \Exception('此收入無法取消');
        }

        $this->update([
            'status' => self::STATUS_CANCELLED,
        ]);
    }

    /**
     * 建立出納日記帳記錄
     */
    protected function createCashierLedgerEntry(): CashierLedgerEntry
    {
        $bankAccount = $this->bank_account ?? 'Main Account';
        $balanceBefore = CashierLedgerEntry::getLatestBalance($bankAccount);

        $ledgerEntry = CashierLedgerEntry::create([
            'entry_date' => $this->income_date,
            'entry_type' => CashierLedgerEntry::ENTRY_TYPE_RECEIPT,
            'payment_method' => $this->payment_method,
            'bank_account' => $bankAccount,
            'amount' => $this->amount,
            'balance_before' => $balanceBefore,
            'balance_after' => $balanceBefore + $this->amount,
            'receipt_number' => $this->receipt_number,
            'transaction_reference' => $this->transaction_reference,
            'recorded_by_cashier_id' => $this->recorded_by_cashier_id,
            'recorded_at' => now(),
            'notes' => "收入確認：{$this->title} ({$this->income_number})",
        ]);

        $this->update(['cashier_ledger_entry_id' => $ledgerEntry->id]);

        return $ledgerEntry;
    }

    /**
     * 產生會計分錄
     */
    protected function generateAccountingEntries(): void
    {
        // 借方：資產帳戶（現金或銀行存款）
        $assetAccountId = $this->getAssetAccountId();

        AccountingEntry::create([
            'income_id' => $this->id,
            'chart_of_account_id' => $assetAccountId,
            'entry_type' => AccountingEntry::ENTRY_TYPE_DEBIT,
            'amount' => $this->amount,
            'entry_date' => $this->income_date,
            'description' => "收入：{$this->title} ({$this->income_number})",
        ]);

        // 貸方：收入科目
        AccountingEntry::create([
            'income_id' => $this->id,
            'chart_of_account_id' => $this->chart_of_account_id,
            'entry_type' => AccountingEntry::ENTRY_TYPE_CREDIT,
            'amount' => $this->amount,
            'entry_date' => $this->income_date,
            'description' => "收入：{$this->title} ({$this->income_number})",
        ]);
    }

    /**
     * 根據付款方式取得資產帳戶 ID
     */
    protected function getAssetAccountId(): int
    {
        $accountCode = match ($this->payment_method) {
            self::PAYMENT_METHOD_BANK_TRANSFER => '1201', // 銀行存款
            self::PAYMENT_METHOD_CHECK => '1201',         // 銀行存款
            default => '1101',                            // 現金
        };

        return ChartOfAccount::where('account_code', $accountCode)->value('id') ?? 1;
    }

    // ========== 文字取得 ==========

    /**
     * 取得收入類型文字
     */
    public function getIncomeTypeText(): string
    {
        return match ($this->income_type) {
            self::TYPE_MEMBERSHIP_FEE => '會費收入',
            self::TYPE_ENTRANCE_FEE => '入會費收入',
            self::TYPE_DONATION => '捐款收入',
            self::TYPE_ACTIVITY => '活動收入',
            self::TYPE_GRANT => '補助收入',
            self::TYPE_INTEREST => '利息收入',
            self::TYPE_OTHER => '其他收入',
            default => '未知',
        };
    }

    /**
     * 取得狀態文字
     */
    public function getStatusText(): string
    {
        return match ($this->status) {
            self::STATUS_PENDING => '待確認',
            self::STATUS_CONFIRMED => '已確認',
            self::STATUS_CANCELLED => '已取消',
            default => '未知',
        };
    }

    /**
     * 取得付款方式文字
     */
    public function getPaymentMethodText(): string
    {
        return match ($this->payment_method) {
            self::PAYMENT_METHOD_CASH => '現金',
            self::PAYMENT_METHOD_BANK_TRANSFER => '銀行轉帳',
            self::PAYMENT_METHOD_CHECK => '支票',
            default => '未知',
        };
    }

    /**
     * 取得狀態標籤屬性
     */
    public function getStatusLabelAttribute(): string
    {
        return $this->getStatusText();
    }

    // ========== 收入類型與科目對應 ==========

    /**
     * 取得收入類型對應的預設會計科目代碼
     */
    public static function getDefaultAccountCode(string $incomeType): string
    {
        return match ($incomeType) {
            self::TYPE_MEMBERSHIP_FEE => '4101',
            self::TYPE_ENTRANCE_FEE => '4102',
            self::TYPE_DONATION => '4201',
            self::TYPE_ACTIVITY => '4402',
            self::TYPE_GRANT => '4301',
            self::TYPE_INTEREST => '4401',
            self::TYPE_OTHER => '4901',
            default => '4901',
        };
    }

    /**
     * 取得收入類型對應的預設會計科目 ID
     */
    public static function getDefaultAccountId(string $incomeType): ?int
    {
        $accountCode = self::getDefaultAccountCode($incomeType);
        return ChartOfAccount::where('account_code', $accountCode)->value('id');
    }

    /**
     * 靜態方法：取得收入類型文字標籤
     */
    public static function getIncomeTypeLabel(string $incomeType): string
    {
        return match ($incomeType) {
            self::TYPE_MEMBERSHIP_FEE => '會費收入',
            self::TYPE_ENTRANCE_FEE => '入會費收入',
            self::TYPE_DONATION => '捐款收入',
            self::TYPE_ACTIVITY => '活動收入',
            self::TYPE_GRANT => '補助收入',
            self::TYPE_INTEREST => '利息收入',
            self::TYPE_OTHER => '其他收入',
            default => '未知',
        };
    }

    // ========== 查詢範圍 ==========

    /**
     * 篩選待確認的收入
     */
    public function scopePending($query)
    {
        return $query->where('status', self::STATUS_PENDING);
    }

    /**
     * 篩選已確認的收入
     */
    public function scopeConfirmed($query)
    {
        return $query->where('status', self::STATUS_CONFIRMED);
    }

    /**
     * 篩選特定收入類型
     */
    public function scopeOfType($query, string $type)
    {
        return $query->where('income_type', $type);
    }

    /**
     * 篩選特定會員
     */
    public function scopeForMember($query, int $memberId)
    {
        return $query->where('member_id', $memberId);
    }

    /**
     * 篩選日期範圍
     */
    public function scopeDateRange($query, $startDate, $endDate)
    {
        return $query->whereBetween('income_date', [$startDate, $endDate]);
    }
}