import {
  SdkClient,
  SdkContext,
  listOperationGroups,
  listOperationsInOperationGroup
} from "@azure-tools/typespec-client-generator-core";
import { ignoreDiagnostics, Model, Program, Type } from "@typespec/compiler";
import { getHttpOperation, HttpOperation } from "@typespec/http";
import {
  hasPagingOperations,
  extractPagedMetadataNested,
  parseNextLinkName,
  parseItemName
} from "../utils/operationUtil.js";


const pageableOperationsKey = Symbol("pageable");
export function getPageable(
  program: Program,
  entity: Type
): string | undefined {
  return program.stateMap(pageableOperationsKey).get(entity);
}

export function extractPageDetailFromCore(
  program: Program,
  client: SdkClient,
  dpgContext: SdkContext
) {
  if (!hasPagingOperations(program, client, dpgContext)) {
    return;
  }
  const nextLinks = new Set<string>();
  const itemNames = new Set<string>();
  // Add default values
  nextLinks.add("nextLink");
  itemNames.add("value");
  const clientOperations = listOperationsInOperationGroup(dpgContext, client);
  for (const clientOp of clientOperations) {
    const route = ignoreDiagnostics(getHttpOperation(program, clientOp));
    // ignore overload base operation
    if (route.overloads && route.overloads?.length > 0) {
      continue;
    }
    extractPageDetailFromCoreForRoute(route);
  }
  const operationGroups = listOperationGroups(dpgContext, client, true);
  for (const operationGroup of operationGroups) {
    const operations = listOperationsInOperationGroup(
      dpgContext,
      operationGroup
    );
    for (const op of operations) {
      const route = ignoreDiagnostics(getHttpOperation(program, op));
      // ignore overload base operation
      if (route.overloads && route.overloads?.length > 0) {
        continue;
      }
      extractPageDetailFromCoreForRoute(route);
    }
  }

  function extractPageDetailFromCoreForRoute(route: HttpOperation) {
    for (const response of route.responses) {
      const paged = extractPagedMetadataNested(program, response.type as Model);
      if (paged) {
        const nextLinkName = parseNextLinkName(paged);
        if (nextLinkName) {
          nextLinks.add(nextLinkName);
        }
        const itemName = parseItemName(paged);
        if (itemName) {
          itemNames.add(itemName);
        }
        // Once we find paged metadata, we don't need to processs any further.
        continue;
      }
    }
  }
  // If there are more than one options for nextLink and item names we need to generate a
  // more complex pagination helper.
  const isComplexPaging = nextLinks.size > 1 || itemNames.size > 1;
  return {
    hasPaging: true,
    pageDetails: {
      itemNames: [...itemNames],
      nextLinkNames: [...nextLinks],
      isComplexPaging
    }
  };
}