import type { Config } from "../config.js";

// Column titles in the "2026 Ticket Audit Logs" table. Change here if needed.
export const AUDIT_COL = {
  summary: "Summary", // primary value column, human-readable
  at: "At",
  code: "Ticket Code",
  people: "People",
  action: "Action",
  name: "Name", // the ticket holder's name
  operator: "Operator", // the gate staff member who performed the action
  remainingAfter: "Remaining After",
} as const;

export interface AuditEntry {
  code: string;
  people: number; // positive = checked in, negative = undo
  name: string;
  operator: string;
  remainingAfter: number;
  at: string; // ISO
  action: "check-in" | "undo" | "ice" | "ice-undo";
}

export interface AuditRow extends AuditEntry {
  id: number;
}

/**
 * Writes/reads check-in audit rows to a separate NocoDB table. Optional: if no
 * audit table is configured, log() is a no-op and recent() returns [].
 * Logging failures are swallowed (they must never block a gate check-in).
 */
export class AuditLogger {
  private readonly base: string;
  private readonly token: string;
  private readonly tableId: string | null;

  constructor(cfg: Pick<Config, "NOCODB_BASE_URL" | "NOCODB_API_TOKEN" | "NOCODB_AUDIT_TABLE_ID">) {
    this.base = cfg.NOCODB_BASE_URL.replace(/\/+$/, "");
    this.token = cfg.NOCODB_API_TOKEN;
    this.tableId = cfg.NOCODB_AUDIT_TABLE_ID ?? null;
  }

  get enabled(): boolean {
    return this.tableId !== null;
  }

  private get url(): string {
    return `${this.base}/api/v2/tables/${this.tableId}/records`;
  }

  async log(entry: AuditEntry): Promise<void> {
    if (!this.tableId) return;
    const sign = entry.people >= 0 ? "+" : "";
    const who = entry.operator ? ` by ${entry.operator}` : "";
    const summary = `${entry.code} ${sign}${entry.people} (${entry.action})${who}`;
    try {
      const res = await fetch(this.url, {
        method: "POST",
        headers: { "xc-token": this.token, "Content-Type": "application/json" },
        body: JSON.stringify({
          [AUDIT_COL.summary]: summary,
          [AUDIT_COL.at]: entry.at,
          [AUDIT_COL.code]: entry.code,
          [AUDIT_COL.people]: entry.people,
          [AUDIT_COL.action]: entry.action,
          [AUDIT_COL.name]: entry.name,
          [AUDIT_COL.operator]: entry.operator,
          [AUDIT_COL.remainingAfter]: entry.remainingAfter,
        }),
      });
      if (!res.ok) {
        const t = await res.text().catch(() => "");
        console.error(`audit log write failed: ${res.status} ${t}`);
      }
    } catch (e: any) {
      console.error(`audit log write error: ${e?.message ?? e}`);
    }
  }

  private mapRow(r: any): AuditRow {
    return {
      id: r.Id,
      code: r[AUDIT_COL.code] ?? "",
      people: Number(r[AUDIT_COL.people]) || 0,
      name: r[AUDIT_COL.name] ?? "",
      operator: r[AUDIT_COL.operator] ?? "",
      remainingAfter: Number(r[AUDIT_COL.remainingAfter]) || 0,
      at: r[AUDIT_COL.at] ?? r.CreatedAt ?? "",
      action: (r[AUDIT_COL.action] ?? "check-in") as AuditEntry["action"],
    };
  }

  /** Every audit row, paginated (for reporting/aggregation). */
  async all(): Promise<AuditRow[]> {
    if (!this.tableId) return [];
    const out: AuditRow[] = [];
    const pageSize = 1000;
    let offset = 0;
    for (;;) {
      const url = new URL(this.url);
      url.searchParams.set("limit", String(pageSize));
      url.searchParams.set("offset", String(offset));
      const res = await fetch(url.toString(), {
        headers: { "xc-token": this.token, "Content-Type": "application/json" },
      });
      if (!res.ok) break;
      const body: any = await res.json().catch(() => ({}));
      const list = body?.list ?? [];
      out.push(...list.map((r: any) => this.mapRow(r)));
      if (!list.length || body?.pageInfo?.isLastPage || list.length < pageSize) break;
      offset += pageSize;
      if (offset > 200000) break;
    }
    return out;
  }

  /** Recent entries, newest first, optionally filtered to one code. */
  async recent(opts: { code?: string; limit?: number } = {}): Promise<AuditRow[]> {
    if (!this.tableId) return [];
    const url = new URL(this.url);
    url.searchParams.set("limit", String(Math.min(opts.limit ?? 50, 200)));
    url.searchParams.set("sort", `-${AUDIT_COL.at}`);
    if (opts.code) {
      url.searchParams.set("where", `(${AUDIT_COL.code},eq,${opts.code.replace(/[(),]/g, " ")})`);
    }
    const res = await fetch(url.toString(), {
      headers: { "xc-token": this.token, "Content-Type": "application/json" },
    });
    if (!res.ok) return [];
    const body: any = await res.json().catch(() => ({}));
    return (body?.list ?? []).map((r: any) => ({
      id: r.Id,
      code: r[AUDIT_COL.code] ?? "",
      people: Number(r[AUDIT_COL.people]) || 0,
      name: r[AUDIT_COL.name] ?? "",
      operator: r[AUDIT_COL.operator] ?? "",
      remainingAfter: Number(r[AUDIT_COL.remainingAfter]) || 0,
      at: r[AUDIT_COL.at] ?? r.CreatedAt ?? "",
      action: (r[AUDIT_COL.action] ?? "check-in") as "check-in" | "undo" | "ice" | "ice-undo",
    }));
  }
}