/**
 * Smartsheet REST API wrapper (no SDK).
 *
 * We use direct REST instead of the official `smartsheet` npm SDK
 * because:
 *   - The SDK has Node 22 compatibility issues (top-level `await` in
 *     a CommonJS module) and pulls in ~1.4MB of transitive deps
 *     (`request`, `request-promise`, `lodash`, etc.).
 *   - REST covers our 3 endpoints cleanly: get sheet metadata, add a
 *     row, search a sheet by column value.
 *   - Smartsheet's own docs recommend REST for simple integrations.
 *
 * Endpoints used (all docs at https://smartsheet.redoc.ly):
 *   - GET  /2.0/sheets/{sheetId}        — sheet metadata + columns
 *   - POST /2.0/sheets/{sheetId}/rows   — add a row
 *   - GET  /2.0/sheets/{sheetId}        — full sheet (used for find-by-column)
 *
 * Auth:
 *   - Bearer token via `Authorization: Bearer <token>` header.
 *   - 300 requests/minute per token. Our drain caps at 50 rows per
 *     cron run, well under the limit.
 *
 * Errors:
 *   - `SmartsheetApiError` is thrown for any non-2xx response. It
 *     carries `status` and `body` for the caller to log.
 */
import "server-only";

const BASE_URL = "https://api.smartsheet.com";

const DEFAULT_TIMEOUT_MS = Number.parseInt(
  process.env.SMARTSHEET_SYNC_TIMEOUT_MS ?? "8000",
  10,
);

export type SmartsheetColumn = {
  /** Numeric column ID, as a string (Smartsheet IDs overflow JS numbers). */
  id: string;
  /** Display name in the sheet header row. */
  title: string;
  /** Column type — TEXT_NUMBER, DATE, PICKLIST, etc. We treat all as text on write. */
  type: string;
  /** Column index in the sheet (0-based). */
  index: number;
};

export type SmartsheetSheetMeta = {
  id: string;
  name: string;
  columns: SmartsheetColumn[];
};

export type SmartsheetCell = {
  columnId: string;
  value: string | number | boolean | null;
};

export class SmartsheetApiError extends Error {
  readonly status: number;
  readonly body: string;
  readonly code: number | null;

  constructor(status: number, body: string, message?: string) {
    super(
      message ??
        `Smartsheet API error ${status}: ${body.slice(0, 200)}${
          body.length > 200 ? "…" : ""
        }`,
    );
    this.name = "SmartsheetApiError";
    this.status = status;
    this.body = body;
    // Smartsheet returns { errorCode, message, ... } on failure
    try {
      const parsed = JSON.parse(body) as { errorCode?: number };
      this.code = parsed.errorCode ?? null;
    } catch {
      this.code = null;
    }
  }
}

async function request<T>(
  method: "GET" | "POST",
  path: string,
  token: string,
  body?: unknown,
): Promise<T> {
  const url = `${BASE_URL}${path}`;
  const controller = new AbortController();
  const timer = setTimeout(() => controller.abort(), DEFAULT_TIMEOUT_MS);

  let res: Response;
  try {
    res = await fetch(url, {
      method,
      headers: {
        Authorization: `Bearer ${token}`,
        "Content-Type": "application/json",
        Accept: "application/json",
        "User-Agent": "RouteCommerce-WaterLog/1.0",
      },
      body: body ? JSON.stringify(body) : undefined,
      signal: controller.signal,
      // Disable Next.js fetch caching for API calls — we always want
      // fresh data from Smartsheet.
      cache: "no-store",
    });
  } catch (err) {
    if ((err as { name?: string }).name === "AbortError") {
      throw new SmartsheetApiError(
        408,
        `Smartsheet request timed out after ${DEFAULT_TIMEOUT_MS}ms`,
      );
    }
    throw new SmartsheetApiError(
      0,
      `Network error contacting Smartsheet: ${(err as Error).message ?? err}`,
    );
  } finally {
    clearTimeout(timer);
  }

  if (!res.ok) {
    const errBody = await res.text();
    throw new SmartsheetApiError(res.status, errBody);
  }

  // Some 204s return no body; guard.
  const text = await res.text();
  if (!text) return undefined as unknown as T;
  return JSON.parse(text) as T;
}

/**
 * Extract the numeric sheet ID from either:
 *   - A bare ID: "123456789012345"
 *   - A URL:    "https://app.smartsheet.com/sheets/abc123?..."
 *
 * Smartsheet has TWO kinds of sheet URLs:
 *   - `https://app.smartsheet.com/sheets/<numeric-id>` — the real ID.
 *     Works against the REST API.
 *   - `https://app.smartsheet.com/sheets/<share-slug>` — a 30+ char
 *     opaque slug for sharing with non-users. The REST API does NOT
 *     accept these; calling `/2.0/sheets/<slug>` returns a 2xx with
 *     an empty/malformed body, which used to crash our parser with
 *     "Cannot read properties of undefined (reading 'id')". We detect
 *     that case here and surface a clear, actionable error so the
 *     admin pastes the numeric ID instead.
 *
 * The numeric ID can be found in the sheet's URL once the user is
 * signed in to Smartsheet, or via File → Properties in the Smartsheet
 * UI.
 */
export function extractSheetId(input: string): string {
  const trimmed = input.trim();
  if (!trimmed) {
    throw new Error("Sheet ID or URL is required");
  }
  // Plain numeric ID — short-circuit.
  if (/^\d+$/.test(trimmed)) return trimmed;

  // URL form — pull the segment after "sheets", or fall back to the
  // last path segment.
  let candidate = trimmed;
  try {
    const url = new URL(trimmed);
    const segments = url.pathname.split("/").filter(Boolean);
    const sheetsIdx = segments.findIndex((s) => s === "sheets");
    if (sheetsIdx >= 0 && segments[sheetsIdx + 1]) {
      candidate = segments[sheetsIdx + 1];
    } else if (segments.length > 0) {
      candidate = segments[segments.length - 1] ?? trimmed;
    }
  } catch {
    // Not a URL — leave `candidate` as the original input.
  }

  // The Smartsheet REST API only accepts numeric IDs. Share-link slugs
  // look like "V4XgwvVJqFjcxQmQMrgwm77WjCP7hpjqqW82RRR1" (30+ chars,
  // base64-ish). Detect and reject them with a clear message BEFORE
  // hitting the API.
  if (!/^\d+$/.test(candidate)) {
    throw new Error(
      "That looks like a Smartsheet share-link slug, not a numeric sheet ID. " +
        "Open the sheet in Smartsheet (signed in) and copy the numeric ID from the URL — " +
        "or use File → Properties to find it. " +
        `Got: "${candidate.slice(0, 12)}${candidate.length > 12 ? "…" : ""}"`,
    );
  }
  return candidate;
}

/**
 * Fetch sheet metadata (columns, name) — used by the "Test Connection"
 * button to populate the column-mapping dropdowns.
 *
 * Calls `GET /2.0/sheets/{sheetId}?pageSize=1` — we only need the
 * header row (column definitions), not the row data, so a 1-row
 * response keeps the payload tiny.
 */
export async function getSheetMeta(
  sheetId: string,
  token: string,
): Promise<SmartsheetSheetMeta> {
  if (!sheetId) throw new Error("sheetId is required");
  if (!token) throw new Error("token is required");

  type ApiResponse = {
    // NOTE: GET /2.0/sheets/{id} returns a FLAT response (id, name,
    // columns at the top level), NOT wrapped in a `result` envelope.
    // This is different from POST endpoints (which use { result: [...] }).
    // See https://smartsheet.redoc.ly/#operation/getSheet
    id: number;
    name: string;
    columns: Array<{
      id: number;
      title: string;
      type: string;
      index: number;
    }>;
  };

  const data = await request<ApiResponse>(
    "GET",
    `/2.0/sheets/${encodeURIComponent(sheetId)}?pageSize=1`,
    token,
  );

  // Defensive: if Smartsheet returns a 2xx without `id`, something is
  // wrong (older API version, account-level issue, etc.). Without this
  // guard we'd crash with "Cannot read properties of undefined (reading
  // 'id')" deep in the column-mapping render. `extractSheetId` catches
  // share-link slugs up front; this guard is belt-and-suspenders for
  // anything else.
  if (!data || data.id == null) {
    throw new SmartsheetApiError(
      502,
      `Smartsheet returned an unexpected response for sheet ${sheetId} ` +
        `(missing id at top level). If you pasted a Smartsheet share-link ` +
        `URL, paste the numeric sheet ID instead — open the sheet in ` +
        `Smartsheet while signed in and copy the number from the address bar.`,
    );
  }

  return {
    id: String(data.id),
    name: data.name ?? "(unnamed sheet)",
    columns: (data.columns ?? []).map((c) => ({
      id: c.id != null ? String(c.id) : "",
      title: c.title ?? "",
      type: c.type ?? "TEXT_NUMBER",
      index: c.index ?? 0,
    })),
  };
}

/**
 * Add a row to a sheet. `cells` is mapped to Smartsheet's
 * `[{columnId, value, strict?}]` shape. Boolean values are coerced
 * to "TRUE"/"FALSE" (Smartsheet wants strings for PICKLIST columns).
 *
 * Returns the new row's `id` and `rowNumber`.
 */
export async function addRow(
  sheetId: string,
  token: string,
  cells: SmartsheetCell[],
): Promise<{ rowId: string; rowNumber: number }> {
  if (!sheetId) throw new Error("sheetId is required");
  if (!token) throw new Error("token is required");
  if (cells.length === 0) throw new Error("addRow: cells must not be empty");

  const toCellValue = (
    v: string | number | boolean | null,
  ): string | boolean | number => {
    if (v === null || v === undefined) return "";
    if (typeof v === "boolean") return v;
    return v;
  };

  // NOTE: POST /2.0/sheets/{id}/rows response shape varies:
  //   - One row in request  →  result: { id, rowNumber, ... }  (single object)
  //   - Multiple rows        →  result: [{ id, rowNumber, ... }, ...]  (array)
  // We always post exactly one row, but handle both defensively. Different
  // from the flat GET /2.0/sheets/{id} response.
  // See https://smartsheet.redoc.ly/#operation/addRows
  type ApiResponse = {
    result:
      | { id: number; rowNumber: number; [k: string]: unknown }
      | Array<{ id: number; rowNumber: number; [k: string]: unknown }>;
    resultCode?: number;
    message?: string;
  };

  const data = await request<ApiResponse>(
    "POST",
    `/2.0/sheets/${encodeURIComponent(sheetId)}/rows`,
    token,
    // Body MUST be a top-level array (or single Row object), NOT wrapped
    // in { rows: [...] }. When wrapped, Smartsheet returns HTTP 200 +
    // resultCode 0 + "SUCCESS" but silently drops every cell value —
    // creates empty rows. (Verified by direct probe: POSTing with
    // { rows: [...] } returns 200 with no values persisted; POSTing with
    // [...] returns 200 with values persisted.) This was the root cause
    // of "rows created but data not inserted" — see the Smartsheet docs
    // cURL example for POST /sheets/{id}/rows.
    [
      {
        cells: cells.map((c) => ({
          columnId: Number(c.columnId),
          value: toCellValue(c.value),
        })),
      },
    ],
  );

  const result = data?.result;
  const row = Array.isArray(result) ? result[0] : result;
  if (!row || row.id == null) {
    throw new SmartsheetApiError(
      502,
      `Smartsheet POST /sheets/${sheetId}/rows returned no row. ` +
        `Response: ${JSON.stringify(data).slice(0, 200)}`,
    );
  }
  return {
    rowId: String(row.id),
    rowNumber: row.rowNumber,
  };
}

/**
 * Find an existing row by a column value. Used for dedup — if a row
 * already exists for the given `entry_id`, skip the insert and
 * record the existing row ID in the queue.
 *
 * Implementation: scans the sheet's `columnId` column for `value`.
 * This is O(n) on sheet size; acceptable for typical water-log sheets
 * (< 10k rows/yr) but would need a search endpoint for huge sheets.
 * Smartsheet does not expose a server-side "find by column" endpoint.
 */
export async function findRowByColumn(
  sheetId: string,
  token: string,
  columnId: string,
  value: string,
): Promise<{ rowId: string; rowNumber: number } | null> {
  if (!sheetId || !token || !columnId) return null;
  // We use `pageSize=1` is useless for search; fetch the whole sheet.
  // For sheets up to ~10k rows this is fine. For larger, admin should
  // switch to a sheet-summary API or a backend search.
  type ApiResponse = {
    rows: Array<{
      id: number;
      rowNumber: number;
      cells: Array<{ columnId: number; value?: string | number | boolean | null }>;
    }>;
  };

  let allRows: ApiResponse["rows"] = [];
  let page = 1;
  const PAGE_SIZE = 500;
  // Bound the search to 5 pages (2,500 rows) to avoid runaway fetches.
  const MAX_PAGES = 5;

  while (page <= MAX_PAGES) {
    const data = await request<ApiResponse>(
      "GET",
      `/2.0/sheets/${encodeURIComponent(sheetId)}?pageSize=${PAGE_SIZE}&page=${page}`,
      token,
    );
    if (data.rows.length === 0) break;
    allRows = allRows.concat(data.rows);
    if (data.rows.length < PAGE_SIZE) break;
    page += 1;
  }

  for (const row of allRows) {
    const cell = row.cells.find((c) => String(c.columnId) === String(columnId));
    if (cell && String(cell.value ?? "") === String(value)) {
      return { rowId: String(row.id), rowNumber: row.rowNumber };
    }
  }
  return null;
}