import type { PostProcessor } from '@hey-api/shared';
import { resolveSource, valueToObject } from '@hey-api/shared';
import type { MaybeArray } from '@hey-api/types';

import { postProcessors } from './postprocess';
import type { Output, UserOutput } from './types';

export function getOutput(userConfig: { output: MaybeArray<string | UserOutput> }): Output {
  if (userConfig.output instanceof Array) {
    throw new Error(
      'Unexpected array of outputs in user configuration. This should have been expanded already.',
    );
  }

  const userOutput =
    typeof userConfig.output === 'string' ? { path: userConfig.output } : (userConfig.output ?? {});

  const output = valueToObject({
    defaultValue: {
      clean: true,
      entryFile: true,
      fileName: {
        case: 'preserve',
        name: '{{name}}',
        suffix: '_gen',
      },
      header: '# This file is auto-generated by @hey-api/openapi-python',
      path: '',
      postProcess: [],
      preferExportAll: false,
    },
    mappers: {
      object: (fields, defaultValue) => ({
        ...fields,
        fileName: valueToObject({
          defaultValue: {
            ...(defaultValue.fileName as Extract<
              typeof defaultValue.fileName,
              Record<string, unknown>
            >),
          },
          mappers: {
            function: (name) => ({ name }),
            string: (name) => ({ name }),
          },
          value: fields.fileName,
        }),
      }),
    },
    value: userOutput,
  }) as Output;
  if (output.importFileExtension && !output.importFileExtension.startsWith('.')) {
    output.importFileExtension = `.${output.importFileExtension}`;
  }
  output.postProcess = normalizePostProcess(userOutput.postProcess);
  output.source = resolveSource(output);
  return output;
}

function normalizePostProcess(input: UserOutput['postProcess']): ReadonlyArray<PostProcessor> {
  if (!input) return [];

  return input.map((item) => {
    if (typeof item === 'string') {
      const preset = postProcessors[item];
      if (!preset) {
        throw new Error(`Unknown post-processor preset: "${item}"`);
      }
      return preset;
    }
    return {
      name: item.name ?? item.command,
      ...item,
    };
  });
}