export type AgentReplacementTaskModeType =
  | "detail_replacement"
  | "sku_replacement";

export type AgentReplacementTaskStatus =
  | "pending"
  | "running"
  | "succeeded"
  | "failed";

export interface AgentReplacementTaskSnapshot {
  id: string;
  modeType: AgentReplacementTaskModeType;
  referenceId: string;
  messageId?: string | null;
  status: AgentReplacementTaskStatus;
  error: string | null;
  result: unknown;
  createdAt: string;
  startedAt: string | null;
  completedAt: string | null;
  queueStatus?: {
    queuePosition?: number | null;
    sameModelPendingCount?: number | null;
    sameModelRunningCount?: number | null;
    concurrencyLimit?: number | null;
    estimatedWaitMs?: number | null;
  } | null;
}

export type AgentReplacementCardStatus =
  | "waiting"
  | "queued"
  | "generating"
  | "completed"
  | "passthrough"
  | "fallback"
  | "failed"
  | "missing";

function toTimestamp(value: string | null | undefined) {
  const timestamp = Date.parse(String(value || ""));
  return Number.isFinite(timestamp) ? timestamp : 0;
}

export function buildLatestAgentReplacementTaskMap(params: {
  tasks: AgentReplacementTaskSnapshot[];
  modeType: AgentReplacementTaskModeType;
}) {
  const result = new Map<string, AgentReplacementTaskSnapshot>();
  const orderedTasks = [...params.tasks].sort(
    (left, right) => toTimestamp(right.createdAt) - toTimestamp(left.createdAt)
  );

  for (const task of orderedTasks) {
    if (
      task.modeType !== params.modeType ||
      !task.referenceId ||
      result.has(task.referenceId)
    ) {
      continue;
    }
    result.set(task.referenceId, task);
  }

  return result;
}

export function isAgentReplacementTaskInPendingRun(params: {
  task: AgentReplacementTaskSnapshot | null | undefined;
  pendingStartedAt?: number | null;
  requestMessageId?: string | null;
  clockSkewAllowanceMs?: number;
}) {
  if (!params.task) {
    return false;
  }
  const taskMessageId = String(params.task.messageId || "").trim();
  const requestMessageId = String(params.requestMessageId || "").trim();
  if (taskMessageId && requestMessageId) {
    return taskMessageId === requestMessageId;
  }
  if (!Number.isFinite(Number(params.pendingStartedAt))) {
    return true;
  }

  const taskCreatedAt = toTimestamp(params.task.createdAt);
  const pendingStartedAt = Number(params.pendingStartedAt);
  const clockSkewAllowanceMs = Math.max(0, params.clockSkewAllowanceMs ?? 15_000);
  return taskCreatedAt >= pendingStartedAt - clockSkewAllowanceMs;
}

export function getAgentReplacementTaskResultImageUrl(result: unknown) {
  if (!result || typeof result !== "object" || Array.isArray(result)) {
    return null;
  }

  const images = (result as { images?: unknown }).images;
  if (!Array.isArray(images)) {
    return null;
  }

  for (const image of images) {
    if (!image || typeof image !== "object" || Array.isArray(image)) {
      continue;
    }
    const record = image as Record<string, unknown>;
    const originalUrl = String(record.originalUrl || "").trim();
    if (/^https?:\/\//i.test(originalUrl)) {
      return originalUrl;
    }
    const thumbnailUrl = String(record.thumbnailUrl || "").trim();
    if (/^https?:\/\//i.test(thumbnailUrl)) {
      return thumbnailUrl;
    }
  }

  return null;
}

export function resolveAgentReplacementCardStatus(params: {
  resultUrl: string | null;
  persistedResultStatus?: "completed" | "passthrough" | "fallback" | null;
  taskStatus?: AgentReplacementTaskStatus | null;
  isRequestedInPendingRun: boolean;
  isGenerating: boolean;
  index: number;
  generatedCount: number;
  activeRunIndex?: number | null;
}): AgentReplacementCardStatus {
  if (params.taskStatus === "pending") {
    return "queued";
  }
  if (params.taskStatus === "running") {
    return "generating";
  }

  if (params.resultUrl) {
    if (
      params.persistedResultStatus === "passthrough" ||
      params.persistedResultStatus === "fallback"
    ) {
      return params.persistedResultStatus;
    }
    if (params.taskStatus === "failed") {
      return "failed";
    }
    return "completed";
  }

  if (params.taskStatus === "failed") {
    return "failed";
  }
  if (params.taskStatus === "succeeded") {
    return "missing";
  }

  if (params.isRequestedInPendingRun) {
    return "queued";
  }

  if (
    typeof params.activeRunIndex === "number" &&
    params.activeRunIndex >= 0 &&
    params.generatedCount <= params.activeRunIndex
  ) {
    if (params.isGenerating) {
      return params.generatedCount === params.activeRunIndex ? "generating" : "queued";
    }
    if (params.generatedCount > 0) {
      return "missing";
    }
  }

  if (params.isGenerating) {
    return params.index === params.generatedCount ? "generating" : "queued";
  }
  if (params.generatedCount > 0 && params.index >= params.generatedCount) {
    return "missing";
  }
  return "waiting";
}