<?php
if (!defined('ABSPATH')) exit;

/**
 * Healthcheck session. Option-backed (single in-progress session per site).
 *
 * Per beads decision hc-5ix.4: option, not CPT. The plugin is installed per
 * engagement, so per-site history living in the DB would die on uninstall.
 * Reports are exported as Markdown instead — see report.php.
 */
final class WPH_Session {

    public const STATUS_NOT_STARTED = 'not_started';
    public const STATUS_DONE        = 'done';
    public const STATUS_SKIPPED     = 'skipped';
    public const STATUS_BLOCKED     = 'blocked';
    public const STATUS_NA          = 'n_a';

    public const VALID_STATUSES = [
        self::STATUS_NOT_STARTED,
        self::STATUS_DONE,
        self::STATUS_SKIPPED,
        self::STATUS_BLOCKED,
        self::STATUS_NA,
    ];

    private array $data;

    private function __construct(array $data) {
        $this->data = $data;
    }

    public static function current(): ?self {
        $raw = get_option(WPH_OPT_SESSION);
        if (!is_array($raw) || empty($raw['id'])) return null;
        return new self($raw);
    }

    public static function start(int $technician_id): self {
        $data = [
            'id'           => uniqid('wph_', true),
            'started_at'   => time(),
            'finished_at'  => null,
            'technician_id'=> $technician_id,
            'site_url'     => get_site_url(),
            'wp_version'   => get_bloginfo('version'),
            'php_version'  => PHP_VERSION,
            'steps'        => [], // keyed by step id → ['status' => ..., 'notes' => ..., 'updated_at' => ...]
        ];
        update_option(WPH_OPT_SESSION, $data, false);
        return new self($data);
    }

    public static function discard(): void {
        delete_option(WPH_OPT_SESSION);
    }

    public function id(): string                { return (string) $this->data['id']; }
    public function started_at(): int           { return (int) $this->data['started_at']; }
    public function finished_at(): ?int         { return isset($this->data['finished_at']) ? (int) $this->data['finished_at'] : null; }
    public function is_finished(): bool         { return $this->finished_at() !== null; }
    public function technician_id(): int        { return (int) $this->data['technician_id']; }
    public function site_url(): string          { return (string) ($this->data['site_url'] ?? get_site_url()); }
    public function wp_version(): string        { return (string) ($this->data['wp_version'] ?? ''); }
    public function php_version(): string       { return (string) ($this->data['php_version'] ?? ''); }
    public function data(): array               { return $this->data; }

    public function step_state(string $step_id): array {
        return $this->data['steps'][$step_id] ?? [
            'status'     => self::STATUS_NOT_STARTED,
            'notes'      => '',
            'updated_at' => null,
        ];
    }

    public function update_step(string $step_id, string $status, string $notes): void {
        if (!in_array($status, self::VALID_STATUSES, true)) {
            $status = self::STATUS_NOT_STARTED;
        }
        $this->data['steps'][$step_id] = [
            'status'     => $status,
            'notes'      => $notes,
            'updated_at' => time(),
        ];
        update_option(WPH_OPT_SESSION, $this->data, false);
    }

    public function finish(): void {
        $this->data['finished_at'] = time();
        update_option(WPH_OPT_SESSION, $this->data, false);
    }

    /** Store the result of running autocheck() on a step. */
    public function set_autocheck(string $step_id, array $findings): void {
        $this->data['autocheck'][$step_id] = [
            'checked_at' => time(),
            'findings'   => $findings,
        ];
        update_option(WPH_OPT_SESSION, $this->data, false);
    }

    /** Returns ['checked_at'=>int, 'findings'=>array] or null. */
    public function get_autocheck(string $step_id): ?array {
        return $this->data['autocheck'][$step_id] ?? null;
    }

    public function progress(): array {
        $steps = WPH_Steps::instance()->all();
        $total = count($steps);
        $done  = 0;
        foreach ($steps as $step) {
            $st = $this->step_state($step->id());
            if (in_array($st['status'], [self::STATUS_DONE, self::STATUS_SKIPPED, self::STATUS_NA], true)) {
                $done++;
            }
        }
        return ['done' => $done, 'total' => $total];
    }
}