<?php
defined( 'ABSPATH' ) || exit;

/**
 * Actor Handoff Log — two-axis attribution (Board #23).
 *
 * Provides a clear, auditable boundary between AI-operated actor mode
 * and human-operated actor mode WITHOUT mutating Fluent's own comment
 * tables. Strictly additive: a small dedicated table records who
 * "pressed send" for a given actor-authored comment.
 *
 * The two axes:
 *   created_by    — the actor (Bridget, etc.). The displayed author. Unchanged.
 *   committed_by  — the user who pressed send (a human user, or an agent
 *                   service account user). Recorded here, queried via
 *                   SA_Orch_Actor_Handoff::get_committer().
 *
 * Operator-mode detection — the full provenance chain works once Board #16
 * (Token + Usage Visibility) ships its LLM token log. Until then, the
 * token-presence check returns 'unknown' and detect_mode reflects that
 * honestly:
 *
 *   committer recorded + token row found        → 'ai'
 *   committer recorded + token row NOT found    → 'human'
 *   committer recorded + token state unknown    → 'unknown'  (pre-#16; honest)
 *   committer NOT recorded                      → 'unknown'
 *
 * The token-presence check is implemented as a filter:
 *
 *   apply_filters( 'sa_orch_handoff_has_llm_token', null, $kind, $comment_id );
 *
 * Board #16 will register a callback that consults the token log. The
 * default return of null means "unknown" — never a false positive.
 *
 * Doctrine constraints honored:
 *   - Actors remain non-binding; this layer is observational, not enforcing
 *   - No impact to Board progression rules
 *   - No schema refactors — strictly additive (one new table)
 *   - No Asterion writes
 *   - No automation
 *   - No UI surface beyond what already exists
 */
class SA_Orch_Actor_Handoff {

    const KIND_FLUENT_BOARDS  = 'fluent_boards';
    const KIND_FLUENT_SUPPORT = 'fluent_support';

    const MODE_AI      = 'ai';
    const MODE_HUMAN   = 'human';
    const MODE_UNKNOWN = 'unknown';

    private static function table(): string {
        global $wpdb;
        return $wpdb->prefix . SA_ORCH_DB_PREFIX . 'actor_handoff';
    }

    /**
     * Record (or update) the committer for an actor-authored comment.
     * Idempotent on (kind, comment_id) — re-recording replaces the prior row.
     *
     * Returns true on success, false on invalid input or DB failure.
     */
    public static function record_committer( string $kind, int $comment_id, int $committed_by_user_id ): bool {
        if ( $comment_id <= 0 || $committed_by_user_id <= 0 ) {
            return false;
        }
        $kind = sanitize_key( $kind );
        if ( $kind === '' ) return false;

        global $wpdb;
        $tbl = self::table();
        // Replace prior row, if any. Keeps the table thin.
        $wpdb->delete( $tbl, [
            'comment_kind' => $kind,
            'comment_id'   => $comment_id,
        ] );
        $ok = $wpdb->insert( $tbl, [
            'comment_kind'         => $kind,
            'comment_id'           => $comment_id,
            'committed_by_user_id' => $committed_by_user_id,
            'recorded_at'          => current_time( 'mysql', true ),
        ] );
        return $ok !== false;
    }

    /**
     * Get the recorded committer for a comment, or null if none recorded.
     */
    public static function get_committer( string $kind, int $comment_id ): ?int {
        if ( $comment_id <= 0 ) return null;
        $kind = sanitize_key( $kind );
        if ( $kind === '' ) return null;

        global $wpdb;
        $row = $wpdb->get_var( $wpdb->prepare(
            "SELECT committed_by_user_id FROM " . self::table() . "
             WHERE comment_kind = %s AND comment_id = %d
             ORDER BY id DESC LIMIT 1",
            $kind,
            $comment_id
        ) );
        return $row !== null ? (int) $row : null;
    }

    /**
     * Detect operator mode for a comment. Returns one of the MODE_* constants.
     * Never lies about uncertainty — returns 'unknown' rather than guessing.
     */
    public static function detect_mode( string $kind, int $comment_id ): string {
        $committer = self::get_committer( $kind, $comment_id );
        if ( $committer === null ) {
            return self::MODE_UNKNOWN;
        }

        /**
         * Filter that signals whether an LLM token row exists for this commit.
         * Returns: true (token row found → AI mode),
         *          false (no token row → human mode),
         *          null (unknown — token log not yet integrated, default).
         *
         * Board #16 will register a callback that consults the token log.
         */
        $token_present = apply_filters(
            'sa_orch_handoff_has_llm_token',
            null,
            $kind,
            $comment_id
        );

        if ( $token_present === null )  return self::MODE_UNKNOWN;
        if ( $token_present === true )  return self::MODE_AI;
        return self::MODE_HUMAN;
    }
}