<?php

namespace App\Models;

use App\Models\Concerns\HasUuid;
use App\Provisioning\Contracts\ProvisioningSubject;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\Relations\MorphMany;

class Host extends Model implements ProvisioningSubject
{
    /** @use HasFactory<\Database\Factories\HostFactory> */
    use HasFactory, HasUuid;

    protected $fillable = [
        'name', 'datacenter', 'cluster', 'public_ip', 'wg_ip', 'wg_pubkey',
        'ssh_host_key', 'api_token_ref', 'total_gb', 'total_ram_mb', 'cpu_cores',
        'cpu_weight', 'reserve_pct', 'pve_version', 'node', 'status', 'last_seen_at',
    ];

    protected $hidden = ['api_token_ref'];

    protected function casts(): array
    {
        return [
            'api_token_ref' => 'encrypted',
            'last_seen_at' => 'datetime',
            'total_gb' => 'integer',
            'total_ram_mb' => 'integer',
            'cpu_cores' => 'integer',
            'cpu_weight' => 'integer',
            'reserve_pct' => 'integer',
        ];
    }

    /** Placement runs (polymorphic subject). */
    public function runs(): MorphMany
    {
        return $this->morphMany(ProvisioningRun::class, 'subject');
    }

    /** Runner hook: a failed onboarding run moves the host to the error status. */
    public function onProvisioningFailed(): void
    {
        $this->update(['status' => 'error']);
    }

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

    /** Free committable storage: total minus reserve. */
    public function freeGb(): int
    {
        if ($this->total_gb === null) {
            return 0;
        }

        return (int) floor($this->total_gb * (100 - $this->reserve_pct) / 100);
    }

    /**
     * Host storage already committed, counted as the VM disk allocation
     * (disk_gb) since that is what is actually placed on the host — not the
     * (smaller) Nextcloud user quota. A failed instance still counts while its VM
     * exists (has a vmid); a failure before any VM was created releases it.
     */
    public function committedGb(): int
    {
        return (int) $this->instances()
            ->where(fn ($q) => $q->where('status', '!=', 'failed')->orWhereNotNull('vmid'))
            ->sum('disk_gb');
    }

    /** Storage still available for new instances. */
    public function availableGb(): int
    {
        return max(0, $this->freeGb() - $this->committedGb());
    }

    /** Used-storage percentage (committed vs committable free), 0–100. */
    public function usedPct(): int
    {
        $free = $this->freeGb();

        return $free > 0 ? min(100, (int) round($this->committedGb() / $free * 100)) : 0;
    }

    /**
     * Heartbeat health from last_seen_at: online (≤5 min), stale (≤30 min),
     * offline (older or never seen). Drives the health dot in the console.
     */
    public function healthState(): string
    {
        if ($this->last_seen_at === null) {
            return 'offline';
        }
        $minutes = $this->last_seen_at->diffInMinutes(now());

        return match (true) {
            $minutes <= 5 => 'online',
            $minutes <= 30 => 'stale',
            default => 'offline',
        };
    }

    /**
     * Placement (spec §1): first active host in the datacenter with enough free
     * committable storage. Cluster is ignored in v1.0.
     */
    public static function placeableIn(string $datacenter, int $quotaGb): ?self
    {
        return self::query()
            ->where('datacenter', $datacenter)
            ->where('status', 'active')
            ->orderBy('name')
            ->get()
            ->first(fn (self $host) => $host->availableGb() >= $quotaGb);
    }
}