import ts from "typescript";
import {
  NEVER,
  QUESTION_TOKEN,
  addJSDocComment,
  oapiRef,
  tsModifiers,
  tsPropertyIndex,
} from "../lib/ts.js";
import { createRef } from "../lib/utils.js";
import {
  OperationObject,
  ParameterObject,
  PathItemObject,
  ReferenceObject,
  TransformNodeOptions,
} from "../types.js";
import transformOperationObject, {
  injectOperationObject,
} from "./operation-object.js";
import { transformParametersArray } from "./parameters-array.js";

export type Method =
  | "get"
  | "put"
  | "post"
  | "delete"
  | "options"
  | "head"
  | "patch"
  | "trace";

/**
 * Transform PathItem nodes (4.8.9)
 * @see https://spec.openapis.org/oas/v3.1.0#path-item-object
 */
export default function transformPathItemObject(
  pathItem: PathItemObject,
  options: TransformNodeOptions,
): ts.TypeNode {
  const type: ts.TypeElement[] = [];

  // parameters
  type.push(
    ...transformParametersArray(pathItem.parameters ?? [], {
      ...options,
      path: createRef([options.path!, "parameters"]),
    }),
  );

  // methods
  for (const method of [
    "get",
    "put",
    "post",
    "delete",
    "options",
    "head",
    "patch",
    "trace",
  ] as Method[]) {
    const operationObject = pathItem[method];
    if (
      !operationObject ||
      (options.ctx.excludeDeprecated &&
        ("$ref" in operationObject
          ? options.ctx.resolve<OperationObject>(operationObject.$ref)
          : operationObject
        )?.deprecated)
    ) {
      type.push(
        ts.factory.createPropertySignature(
          /* modifiers     */ tsModifiers({ readonly: options.ctx.immutable }),
          /* name          */ tsPropertyIndex(method),
          /* questionToken */ QUESTION_TOKEN,
          /* type          */ NEVER,
        ),
      );
      continue;
    }

    // fold top-level PathItem parameters into method-level, with the latter overriding the former
    const keyedParameters: Record<string, ParameterObject | ReferenceObject> =
      {};
    if (!("$ref" in operationObject)) {
      // important: OperationObject parameters come last, and will override any conflicts with PathItem parameters
      for (const parameter of [
        ...(pathItem.parameters ?? []),
        ...(operationObject.parameters ?? []),
      ]) {
        // note: the actual key doesn’t matter here, as long as it can match between PathItem and OperationObject
        keyedParameters["$ref" in parameter ? parameter.$ref : parameter.name] =
          parameter;
      }
    }

    let operationType: ts.TypeNode;
    if ("$ref" in operationObject) {
      operationType = oapiRef(operationObject.$ref);
    }
    // if operationId exists, move into an `operations` export and pass the reference in here
    else if (operationObject.operationId) {
      operationType = oapiRef(
        createRef(["operations", operationObject.operationId]),
      );
      injectOperationObject(
        operationObject.operationId,
        { ...operationObject, parameters: Object.values(keyedParameters) },
        { ...options, path: createRef([options.path!, method]) },
      );
    } else {
      operationType = ts.factory.createTypeLiteralNode(
        transformOperationObject(
          { ...operationObject, parameters: Object.values(keyedParameters) },
          { ...options, path: createRef([options.path!, method]) },
        ),
      );
    }
    const property = ts.factory.createPropertySignature(
      /* modifiers     */ tsModifiers({ readonly: options.ctx.immutable }),
      /* name          */ tsPropertyIndex(method),
      /* questionToken */ undefined,
      /* type          */ operationType,
    );
    addJSDocComment(operationObject, property);
    type.push(property);
  }

  return ts.factory.createTypeLiteralNode(type);
}