import { apiRequestBlob, apiRequestData } from "./http";
import type { ExpenseStandardCheck, PrecheckResponse, RiskFlag } from "./feeControl";
import { buildAttachmentFileUrl, type AttachmentGovernanceFields } from "../lib/attachmentGovernance";
import type { ProcessingProgress, ProcessingStage } from "../types/processingProgress";

export type ReimbursementStatus =
  | "draft"
  | "reviewing"
  | "approved"
  | "paid"
  | "rejected"
  | "cancelled";

export type ReimbursementItem = {
  id: string;
  expenseTypeId: string | null;
  expenseDate: string | null;
  amount: string;
  description: string | null;
  assetPriorApprovalBasis?: string | null;
  expenseType: {
    id: string;
    code: string;
    name: string;
    category: string;
    enabled: boolean;
    requiresInvoice?: boolean;
  } | null;
};

export type LinkedTravelRequestSummary = {
  id: string;
  requestNo: string | null;
  purpose: string | null;
  startDate: string | null;
  endDate: string | null;
  estimatedAmount: string;
};

export type ReimbursementListItem = {
  id: string;
  formNumber: string | null;
  status: ReimbursementStatus;
  reimbursementDate: string | null;
  totalAmount: string | null;
  description: string | null;
  payment: {
    paymentVoucherNo: string | null;
    paymentDate: string | null;
    paymentChannel: string | null;
    paidAt: string | null;
    paidBy: string | null;
  };
  owner: {
    id: string;
    employeeNo: string;
    name: string;
  } | null;
  submitter: {
    id: string;
    employeeNo: string;
    name: string;
  } | null;
  project: {
    id: string;
    projectNo: string;
    name: string;
  } | null;
  pendingWorkflow: {
    instanceId: string;
    stepId: string;
    allowedActions: Array<"approve" | "reject" | "return" | "transfer">;
    task: {
      id: string;
      stepName: string;
      assigneeId: string | null;
      assigneeRole: string | null;
    } | null;
  } | null;
  createdAt: string | null;
  updatedAt: string | null;
};

export type ReimbursementListResponse = {
  page: number;
  pageSize: number;
  total: number;
  scope: "own" | "all";
  items: ReimbursementListItem[];
};

export type ReimbursementBudgetHint = {
  budgetId: string;
  budgetCode: string;
  budgetName: string;
  controlMode: "warn" | "block";
  warningThresholdPercent: number;
  allocatedAmount: string;
  usedAmount: string;
  remainingAmount: string;
  currentAmount: string;
  nextUsedAmount: string;
  nextUsagePercent: number;
  exceedsThreshold: boolean;
  exceedsBudget: boolean;
};

export type ReimbursementWorkflowProgress = {
  currentStepIndex: number;
  totalSteps: number;
  steps: Array<{
    id: string;
    name: string;
    status: "completed" | "current" | "pending";
  }>;
};

export type ReimbursementProcessingStage = ProcessingStage;
export type ReimbursementProcessingProgress = ProcessingProgress;

export type ReimbursementApprovalHistoryItem = {
  id: string;
  stepName: string | null;
  action: string;
  actorName: string;
  comment: string | null;
  createdAt: string | null;
};

export type ReimbursementDetail = {
  deletedAt?: string | null;
  id: string;
  formNumber: string | null;
  submitterId: string;
  ownerId: string;
  departmentId: string;
  department: {
    id: string;
    name: string;
  } | null;
  status: ReimbursementStatus;
  createdAt: string | null;
  submittedAt: string | null;
  reimbursementDate: string | null;
  totalAmount: string | null;
  description: string | null;
  travelSummary: {
    isTravel: boolean;
    purpose: string | null;
    location: string | null;
    startDate: string | null;
    endDate: string | null;
  };
  payment: {
    paymentVoucherNo: string | null;
    paymentDate: string | null;
    paymentChannel: string | null;
    paidAt: string | null;
    paidBy: {
      id: string;
      employeeNo: string;
      name: string;
    } | null;
  };
  projectId: string | null;
  linkedTravelRequestId: string | null;
  linkedTravelRequest: LinkedTravelRequestSummary | null;
  project: {
    id: string;
    projectNo: string;
    name: string;
  } | null;
  owner: {
    id: string;
    employee_no: string;
    name: string;
  } | null;
  submitter: {
    id: string;
    employee_no: string;
    name: string;
  } | null;
  invoices: Array<{
    id: string;
    status: string;
    invoiceCode: string | null;
    invoiceNumber: string | null;
    invoiceDate: string | null;
    sellerName: string | null;
    buyerName: string | null;
    documentCategory: string | null;
    documentSubtype: string | null;
    totalAmount: string | null;
    originalName: string | null;
    mimeType: string | null;
    fileSize: number | null;
    linkedItemId: string | null;
    amountEvidenceStatus: "verified" | "manual_review" | "ocr_failed";
  }>;
  attachments: Array<{
    id: string;
    originalName: string;
    mimeType: string;
    fileSize: number;
    fileSha256: string;
  } & AttachmentGovernanceFields & {
    uploadedBy: {
      id: string;
      name: string;
      employeeNo: string;
    } | null;
    createdAt: string | null;
  }>;
  budgetHint: ReimbursementBudgetHint | null;
  pendingWorkflow: {
    instanceId: string;
    stepId: string;
    task: {
      id: string;
      step_name: string;
      assignee_id: string | null;
      assignee_role: string | null;
    } | null;
  } | null;
  workflowProgress: ReimbursementWorkflowProgress | null;
  processingProgress: ReimbursementProcessingProgress;
  approvalHistory: ReimbursementApprovalHistoryItem[];
  riskFlags: RiskFlag[];
  invoiceGuardEnabled?: boolean;
  invoiceAmountManualReviewRequired?: boolean;
  items: ReimbursementItem[];
};

export type ReimbursementListQuery = {
  page?: number;
  pageSize?: number;
  status?: ReimbursementStatus;
  scope?: "own" | "all";
};

export type ReimbursementStatsQuery = {
  dateFrom?: string;
  dateTo?: string;
  departmentId?: string;
};

export type ReimbursementStatsGranularity = "month" | "week";

export type ReimbursementStatsSummary = {
  totalCount: number;
  totalAmount: string;
  byStatus: Record<
    ReimbursementStatus,
    {
      count: number;
      totalAmount: string;
    }
  >;
  avgProcessingDays: number | null;
};

export type ReimbursementStatsTrendItem = {
  period: string | null;
  count: number;
  amount: string;
  paidCount: number;
  paidAmount: string;
};

export type ReimbursementTopExpenseTypeItem = {
  expenseTypeId: string;
  expenseTypeName: string;
  count: number;
  totalAmount: string;
};

export type ReimbursementApprovalBottleneckItem = {
  assigneeId: string | null;
  assigneeName: string;
  pendingCount: number;
  oldestPendingDays: number;
};

export type ReimbursementPayPayload = {
  paymentVoucherNo?: string;
  paymentDate?: string;
  paymentChannel?: "bank" | "alipay" | "wechat" | "cash" | "other";
  paymentNote?: string;
};

export type ReimbursementCreatePayload = {
  ownerEmployeeId?: string;
  reimbursementDate?: string;
  description?: string;
  templateId?: string;
  linkedTravelRequestId?: string;
  travelPurpose?: string;
  travelLocation?: string;
  travelStartDate?: string;
  travelEndDate?: string;
};

export type ReimbursementTravelSummaryPayload = {
  travelPurpose: string | null;
  travelLocation: string | null;
  travelStartDate: string | null;
  travelEndDate: string | null;
};

export type ReimbursementUpdatePayload = Partial<ReimbursementTravelSummaryPayload> & {
  reimbursementDate?: string;
  description?: string | null;
};

export type ReimbursementCreateResponse = {
  id: string;
  formNumber: string | null;
  submitterId: string;
  ownerId: string;
  reimbursementDate: string | null;
  status: ReimbursementStatus;
  description: string | null;
  projectId: string | null;
  project: {
    id: string;
    projectNo: string;
    name: string;
  } | null;
  totalAmount: string;
  linkedTravelRequestId: string | null;
  linkedTravelRequest: LinkedTravelRequestSummary | null;
  items: ReimbursementItem[];
};

export type LinkableTravelRequestSummary = {
  id: string;
  requestNo: string | null;
  purpose: string;
  startDate: string | null;
  endDate: string | null;
  estimatedAmount: string;
};

export type LinkableTravelRequestListResponse = {
  ownerEmployeeId: string;
  items: LinkableTravelRequestSummary[];
};

export type ReimbursementItemPayload = {
  expenseTypeId: string | null;
  expenseDate: string;
  amount: string;
  description?: string;
  assetPriorApprovalBasis?: string | null;
};

export type ReimbursementItemMutationResponse = {
  item: {
    id: string;
    expenseTypeId: string | null;
    expenseDate: string;
    amount: string;
    description: string | null;
    assetPriorApprovalBasis?: string | null;
  };
  totalAmount: string;
};

export type ReimbursementItemDeleteResponse = {
  outcome: "deleted";
  totalAmount: string;
};

export type ReimbursementDeleteResponse = {
  reimbursementId: string;
  outcome: "deleted";
  unboundInvoiceCount: number;
};

export type ReimbursementSubmitResponse = {
  reimbursementId: string;
  formNumber: string;
  workflowInstanceId: string;
  currentTaskId: string;
  status: "reviewing";
  budget: {
    budgetId: string;
    budgetCode: string;
    controlMode: "warn" | "block" | "manual_review";
    usagePercent: number;
    exceededThreshold: boolean;
    exceededBudget: boolean;
  } | null;
  precheckDecision: "pass" | "warn" | "manual_review";
  standardWarnings: ExpenseStandardCheck[];
  openedRiskFlagCount: number;
  invoiceAmountManualReviewRequired: boolean;
  manualReviewItemCount: number;
};

function toQueryString(query: Record<string, string | number | undefined>) {
  const params = new URLSearchParams();

  for (const [key, value] of Object.entries(query)) {
    if (value == null || value === "") {
      continue;
    }
    params.set(key, String(value));
  }

  const encoded = params.toString();
  return encoded ? `?${encoded}` : "";
}

export async function fetchReimbursements(query: ReimbursementListQuery = {}) {
  return apiRequestData<ReimbursementListResponse>(
    `/api/reimbursements${toQueryString(query as Record<string, string | number | undefined>)}`,
  );
}

export async function fetchReimbursementStatsSummary(query: ReimbursementStatsQuery = {}) {
  return apiRequestData<ReimbursementStatsSummary>(
    `/api/reimbursements/stats/summary${toQueryString(query as Record<string, string | number | undefined>)}`,
  );
}

export async function fetchReimbursementStatsTrend(
  query: ReimbursementStatsQuery & { granularity?: ReimbursementStatsGranularity } = {},
) {
  return apiRequestData<{ items: ReimbursementStatsTrendItem[] }>(
    `/api/reimbursements/stats/trend${toQueryString(query as Record<string, string | number | undefined>)}`,
  );
}

export async function fetchReimbursementTopExpenseTypes(
  query: ReimbursementStatsQuery & { limit?: number } = {},
) {
  return apiRequestData<{ items: ReimbursementTopExpenseTypeItem[] }>(
    `/api/reimbursements/stats/top-expense-types${toQueryString(query as Record<string, string | number | undefined>)}`,
  );
}

export async function fetchReimbursementApprovalBottleneck(query: ReimbursementStatsQuery = {}) {
  return apiRequestData<{ items: ReimbursementApprovalBottleneckItem[] }>(
    `/api/reimbursements/stats/approval-bottleneck${toQueryString(query as Record<string, string | number | undefined>)}`,
  );
}

export async function fetchReimbursementDetail(reimbursementId: string) {
  return apiRequestData<ReimbursementDetail>(`/api/reimbursements/${reimbursementId}`);
}

export async function createReimbursement(payload: ReimbursementCreatePayload = {}) {
  return apiRequestData<ReimbursementCreateResponse>(`/api/reimbursements`, {
    method: "POST",
    body: JSON.stringify(payload),
  });
}

export async function fetchLinkableTravelRequests(query: { ownerEmployeeId?: string } = {}) {
  return apiRequestData<LinkableTravelRequestListResponse>(
    `/api/reimbursements/linkable-travel-requests${toQueryString(query as Record<string, string | number | undefined>)}`,
  );
}

export async function precheckReimbursement(reimbursementId: string) {
  return apiRequestData<PrecheckResponse>(`/api/reimbursements/${reimbursementId}/precheck`, {
    method: "POST",
    body: JSON.stringify({}),
  });
}

export async function submitReimbursement(reimbursementId: string) {
  return apiRequestData<ReimbursementSubmitResponse>(`/api/reimbursements/${reimbursementId}/submit`, {
    method: "POST",
    body: JSON.stringify({}),
  });
}

export async function linkReimbursementInvoiceItem(
  reimbursementId: string,
  invoiceId: string,
  linkedItemId: string,
) {
  return apiRequestData<{
    reimbursementId: string;
    invoiceId: string;
    linkedItemId: string;
  }>(`/api/reimbursements/${reimbursementId}/invoices/${invoiceId}/item-link`, {
    method: "PATCH",
    body: JSON.stringify({ linkedItemId }),
  });
}

export async function withdrawReimbursement(reimbursementId: string, comment?: string) {
  return apiRequestData<Record<string, unknown>>(`/api/reimbursements/${reimbursementId}/withdraw`, {
    method: "POST",
    body: JSON.stringify({ comment }),
  });
}

export async function payReimbursement(reimbursementId: string, payload: ReimbursementPayPayload = {}) {
  return apiRequestData<Record<string, unknown>>(`/api/reimbursements/${reimbursementId}/pay`, {
    method: "POST",
    body: JSON.stringify(payload),
  });
}

export async function deleteReimbursement(reimbursementId: string) {
  return apiRequestData<ReimbursementDeleteResponse>(`/api/reimbursements/${reimbursementId}`, {
    method: "DELETE",
  });
}

export async function updateReimbursementTravelSummary(
  reimbursementId: string,
  payload: ReimbursementTravelSummaryPayload,
) {
  return updateReimbursement(reimbursementId, payload);
}

export async function updateReimbursement(
  reimbursementId: string,
  payload: ReimbursementUpdatePayload,
) {
  return apiRequestData<{
    id: string;
    status: ReimbursementStatus;
    reimbursementDate: string;
    description: string | null;
    totalAmount: string;
    travelSummary: Omit<ReimbursementDetail["travelSummary"], "isTravel">;
  }>(`/api/reimbursements/${reimbursementId}`, {
    method: "PATCH",
    body: JSON.stringify(payload),
  });
}

export async function createReimbursementItem(
  reimbursementId: string,
  payload: ReimbursementItemPayload,
) {
  return apiRequestData<ReimbursementItemMutationResponse>(
    `/api/reimbursements/${reimbursementId}/items`,
    {
      method: "POST",
      body: JSON.stringify(payload),
    },
  );
}

export async function updateReimbursementItem(
  reimbursementId: string,
  itemId: string,
  payload: Partial<ReimbursementItemPayload>,
) {
  return apiRequestData<ReimbursementItemMutationResponse>(
    `/api/reimbursements/${reimbursementId}/items/${itemId}`,
    {
      method: "PATCH",
      body: JSON.stringify(payload),
    },
  );
}

export async function deleteReimbursementItem(reimbursementId: string, itemId: string) {
  return apiRequestData<ReimbursementItemDeleteResponse>(
    `/api/reimbursements/${reimbursementId}/items/${itemId}`,
    {
      method: "DELETE",
    },
  );
}

export const MAX_REIMBURSEMENT_ATTACHMENT_FILES = 5;

export async function uploadReimbursementAttachments(reimbursementId: string, files: File[]) {
  const formData = new FormData();
  for (const file of files) {
    formData.append("files", file);
  }

  return apiRequestData<{ items: ReimbursementDetail["attachments"] }>(
    `/api/reimbursements/${reimbursementId}/attachments`,
    {
      method: "POST",
      body: formData,
    },
  );
}

export async function deleteReimbursementAttachment(reimbursementId: string, attachmentId: string, reason: string) {
  return apiRequestData<{ attachmentId: string; outcome: string }>(
    `/api/reimbursements/${reimbursementId}/attachments/${attachmentId}`,
    {
      method: "DELETE",
      body: JSON.stringify({ reason }),
    },
  );
}

export function reimbursementAttachmentFileUrl(reimbursementId: string, attachmentId: string) {
  return `/api/reimbursements/${reimbursementId}/attachments/${attachmentId}/file`;
}

export async function downloadReimbursementAttachment(reimbursementId: string, attachmentId: string, reason?: string) {
  return apiRequestBlob(buildAttachmentFileUrl(reimbursementAttachmentFileUrl(reimbursementId, attachmentId), reason));
}

export async function fetchReimbursementAttachmentPreviewUrl(
  reimbursementId: string,
  attachmentId: string,
  reason?: string,
) {
  return apiRequestData<{
    signedUrl: string;
    expiresAt: string;
    originalName: string;
    mimeType: string;
    fileSize: number;
  }>(`/api/reimbursements/${reimbursementId}/attachments/${attachmentId}/preview-url`, {
    method: "POST",
    body: JSON.stringify(reason ? { reason } : {}),
  });
}

export type ReimbursementMaterialPreviewBundle = {
  expiresAt: string;
  signedUrl: string;
  originalName: string;
  mimeType: "application/pdf";
  fileSize: number;
  pageCount: number;
};

export async function fetchReimbursementMaterialPreviewBundle(
  reimbursementId: string,
  reason?: string,
) {
  return apiRequestData<ReimbursementMaterialPreviewBundle>(
    `/api/reimbursements/${reimbursementId}/materials/preview-bundle`,
    {
      method: "POST",
      body: JSON.stringify(reason ? { reason } : {}),
    },
  );
}


export async function linkReimbursementProject(reimbursementId: string, projectId: string | null) {
  return apiRequestData<{ projectId: string | null; project: { id: string; projectNo: string; name: string } | null }>(`/api/reimbursements/${reimbursementId}/link-project`, {
    method: "POST",
    body: JSON.stringify({ projectId }),
  });
}