<?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 Carbon\Carbon;

class Subscription extends Model
{
    use HasFactory;

    const STATUS_PENDING = 'pending';
    const STATUS_TRIALING = 'trialing';
    const STATUS_ACTIVE = 'active';
    const STATUS_PAST_DUE = 'past_due';
    const STATUS_CANCELED = 'canceled';
    const STATUS_EXPIRED = 'expired';

    protected $fillable = [
        'user_id',
        'plan_id',
        'status',
        'trial_ends_at',
        'current_period_start',
        'current_period_end',
        'canceled_at',
        'ends_at',
        'cancel_reason',
        'paypal_subscription_id',
        'paypal_status',
        'paypal_data',
        'price_paid',
        'currency',
    ];

    protected $casts = [
        'trial_ends_at' => 'datetime',
        'current_period_start' => 'datetime',
        'current_period_end' => 'datetime',
        'canceled_at' => 'datetime',
        'ends_at' => 'datetime',
        'paypal_data' => 'array',
        'price_paid' => 'decimal:2',
    ];

    // ==================== RELATIONSHIPS ====================

    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }

    public function plan(): BelongsTo
    {
        return $this->belongsTo(Plan::class);
    }

    public function invoices(): HasMany
    {
        return $this->hasMany(Invoice::class);
    }

    // ==================== SCOPES ====================

    public function scopeActive($query)
    {
        return $query->whereIn('status', [self::STATUS_TRIALING, self::STATUS_ACTIVE]);
    }

    public function scopeTrialing($query)
    {
        return $query->where('status', self::STATUS_TRIALING);
    }

    public function scopeCanceled($query)
    {
        return $query->where('status', self::STATUS_CANCELED);
    }

    public function scopeExpired($query)
    {
        return $query->where('status', self::STATUS_EXPIRED);
    }

    public function scopeForUser($query, int $userId)
    {
        return $query->where('user_id', $userId);
    }

    // ==================== STATUS CHECKS ====================

    public function isActive(): bool
    {
        return in_array($this->status, [self::STATUS_TRIALING, self::STATUS_ACTIVE]);
    }

    public function isTrialing(): bool
    {
        return $this->status === self::STATUS_TRIALING;
    }

    public function isCanceled(): bool
    {
        return $this->status === self::STATUS_CANCELED;
    }

    public function isExpired(): bool
    {
        return $this->status === self::STATUS_EXPIRED;
    }

    public function isPastDue(): bool
    {
        return $this->status === self::STATUS_PAST_DUE;
    }

    public function onGracePeriod(): bool
    {
        return $this->canceled_at !== null 
            && $this->ends_at !== null 
            && $this->ends_at->isFuture();
    }

    public function hasTrialEnded(): bool
    {
        return $this->trial_ends_at !== null 
            && $this->trial_ends_at->isPast();
    }

    public function isOnTrial(): bool
    {
        return $this->status === self::STATUS_TRIALING
            && $this->trial_ends_at !== null 
            && $this->trial_ends_at->isFuture();
    }

    // ==================== ACCESSORS ====================

    public function getDaysUntilTrialEndsAttribute(): ?int
    {
        if (!$this->trial_ends_at) {
            return null;
        }

        if ($this->trial_ends_at->isPast()) {
            return 0;
        }

        return (int) now()->diffInDays($this->trial_ends_at);
    }

    public function getDaysUntilRenewalAttribute(): ?int
    {
        if (!$this->current_period_end) {
            return null;
        }

        if ($this->current_period_end->isPast()) {
            return 0;
        }

        return (int) now()->diffInDays($this->current_period_end);
    }

    public function getStatusLabelAttribute(): string
    {
        return match ($this->status) {
            self::STATUS_TRIALING => 'En prueba',
            self::STATUS_ACTIVE => 'Activa',
            self::STATUS_PAST_DUE => 'Pago pendiente',
            self::STATUS_CANCELED => 'Cancelada',
            self::STATUS_EXPIRED => 'Expirada',
            default => $this->status,
        };
    }

    public function getStatusColorAttribute(): string
    {
        return match ($this->status) {
            self::STATUS_TRIALING => 'info',
            self::STATUS_ACTIVE => 'success',
            self::STATUS_PAST_DUE => 'warning',
            self::STATUS_CANCELED => 'secondary',
            self::STATUS_EXPIRED => 'danger',
            default => 'secondary',
        };
    }

    // ==================== METHODS ====================

    /**
     * Start a trial for this subscription
     */
    public function startTrial(int $days): self
    {
        $this->status = self::STATUS_TRIALING;
        $this->trial_ends_at = now()->addDays($days);
        $this->current_period_start = now();
        $this->current_period_end = now()->addDays($days);
        $this->save();

        return $this;
    }

    /**
     * Activate the subscription (after trial or payment)
     */
    public function activate(?Carbon $periodEnd = null): self
    {
        $this->status = self::STATUS_ACTIVE;
        $this->trial_ends_at = null;
        $this->current_period_start = now();
        
        if ($periodEnd) {
            $this->current_period_end = $periodEnd;
        } elseif ($this->plan->billing_period === 'monthly') {
            $this->current_period_end = now()->addMonth();
        } elseif ($this->plan->billing_period === 'annual') {
            $this->current_period_end = now()->addYear();
        }
        
        $this->save();

        return $this;
    }

    /**
     * Cancel the subscription
     */
    public function cancel(?string $reason = null, bool $immediately = false): self
    {
        $this->canceled_at = now();
        $this->cancel_reason = $reason;
        
        if ($immediately) {
            $this->status = self::STATUS_CANCELED;
            $this->ends_at = now();
        } else {
            // Keep active until period ends (grace period)
            $this->ends_at = $this->current_period_end;
        }
        
        $this->save();

        return $this;
    }

    /**
     * Mark as expired
     */
    public function markAsExpired(): self
    {
        $this->status = self::STATUS_EXPIRED;
        $this->save();

        return $this;
    }

    /**
     * Renew the subscription for another period
     */
    public function renew(): self
    {
        $this->current_period_start = $this->current_period_end ?? now();
        
        if ($this->plan->billing_period === 'monthly') {
            $this->current_period_end = $this->current_period_start->copy()->addMonth();
        } elseif ($this->plan->billing_period === 'annual') {
            $this->current_period_end = $this->current_period_start->copy()->addYear();
        }
        
        $this->status = self::STATUS_ACTIVE;
        $this->canceled_at = null;
        $this->ends_at = null;
        $this->save();

        return $this;
    }

    /**
     * Swap to a different plan
     */
    public function swap(Plan $newPlan): self
    {
        $this->plan_id = $newPlan->id;
        $this->price_paid = $newPlan->price;
        $this->save();

        return $this;
    }

    /**
     * Create a subscription for a user
     */
    public static function createForUser(User $user, Plan $plan): self
    {
        $subscription = new self([
            'user_id' => $user->id,
            'plan_id' => $plan->id,
            'status' => self::STATUS_TRIALING,
            'price_paid' => $plan->price,
            'currency' => $plan->currency,
        ]);

        if ($plan->is_free) {
            $subscription->status = self::STATUS_ACTIVE;
            $subscription->current_period_start = now();
            $subscription->current_period_end = null; // Never expires
        } elseif ($plan->has_trial) {
            $subscription->trial_ends_at = now()->addDays($plan->trial_days);
            $subscription->current_period_start = now();
            $subscription->current_period_end = now()->addDays($plan->trial_days);
        }

        $subscription->save();

        return $subscription;
    }
}