import { DateTime } from 'luxon';
import type { RenovateConfig } from '../../../config/types.ts';
import { instrument } from '../../../instrumentation/index.ts';
import { logger } from '../../../logger/index.ts';
import { platform } from '../../../modules/platform/index.ts';
import { scm } from '../../../modules/platform/scm.ts';
import { ExternalHostError } from '../../../types/errors/external-host-error.ts';
import { coerceArray } from '../../../util/array.ts';
import { getCache } from '../../../util/cache/repository/index.ts';
import { getInheritedOrGlobal } from '../../../util/common.ts';
import type { BranchConfig } from '../../types.ts';

export async function getPrHourlyCount(
  config: RenovateConfig,
): Promise<number> {
  return await instrument('getPrHourlyCount', async () => {
    try {
      const prList = await platform.getPrList();
      const currentHourStart = DateTime.utc().startOf('hour');
      logger.debug(
        `Calculating PRs created so far in this hour currentHourStart=${String(currentHourStart)}`,
      );
      const soFarThisHour = prList.filter(
        (pr) =>
          pr.sourceBranch !== getInheritedOrGlobal('onboardingBranch') &&
          pr.sourceBranch.startsWith(config.branchPrefix!) &&
          DateTime.fromISO(pr.createdAt!).toUTC() > currentHourStart,
      );
      logger.debug(
        `${soFarThisHour.length} PRs have been created so far in this hour.`,
      );
      return soFarThisHour.length;
    } catch (err) {
      // istanbul ignore if
      if (err instanceof ExternalHostError) {
        throw err;
      }
      logger.error({ err }, 'Error checking PRs created per hour');
      return 0;
    }
  });
}

export async function getConcurrentPrsCount(
  config: RenovateConfig,
  branches: BranchConfig[],
): Promise<number> {
  return await instrument('getConcurrentPrsCount', async () => {
    let openPrCount = 0;
    for (const { branchName } of branches) {
      try {
        const pr = await platform.getBranchPr(branchName, config.baseBranch);
        if (
          pr &&
          pr.sourceBranch !== getInheritedOrGlobal('onboardingBranch') &&
          pr.state === 'open'
        ) {
          openPrCount++;
        }
      } catch (err) {
        // istanbul ignore if
        if (err instanceof ExternalHostError) {
          throw err;
        } else {
          // no-op
        }
      }
    }

    logger.debug(`${openPrCount} PRs are currently open`);
    return openPrCount;
  });
}

export async function getCommitsHourlyCount(
  branches: BranchConfig[],
): Promise<number> {
  return await instrument('getCommitsHourlyCount', async () => {
    try {
      const currentHourStart = DateTime.utc().startOf('hour');
      logger.debug(
        `Calculating commits so far in this hour currentHourStart=${String(currentHourStart)}, for ${branches.length} branches`,
      );

      const cache = getCache();
      const cachedBranches = coerceArray(cache.branches);

      // if we don't have all of our branches in our cache (for instance, if we're not using the Repository Cache, or this is the first run against a repo), we need to fall back to the SCM
      const needsScmFallback = branches.some(
        (branch) =>
          !cachedBranches.find((b) => b.branchName === branch.branchName)
            ?.commitTimestamp,
      );
      const fallbackUpdateDates = needsScmFallback
        ? await scm.getAllBranchUpdateDates()
        : {};

      let soFarThisHour = 0;
      for (const branch of branches) {
        // First try to get from cache
        const branchCache = cachedBranches.find(
          (b) => b.branchName === branch.branchName,
        );

        if (branchCache?.commitTimestamp) {
          const commitTime = DateTime.fromISO(
            branchCache.commitTimestamp,
          ).toUTC();
          if (commitTime > currentHourStart) {
            soFarThisHour++;
          }
        } else {
          // Fallback to SCM if not in cache
          const updateDate = fallbackUpdateDates[branch.branchName];
          if (updateDate && updateDate > currentHourStart) {
            soFarThisHour++;
          }
        }
      }
      logger.debug(`${soFarThisHour} commits so far in this hour.`);
      return soFarThisHour;
    } catch (err) {
      logger.error({ err }, 'Error checking commits per hour');
      return 0;
    }
  });
}

export async function getConcurrentBranchesCount(
  branches: BranchConfig[],
): Promise<number> {
  return await instrument('getConcurrentBranchesCount', async () => {
    let existingBranchCount = 0;
    for (const branch of branches) {
      if (await scm.branchExists(branch.branchName)) {
        existingBranchCount++;
      }
    }

    logger.debug(`${existingBranchCount} already existing branches found.`);
    return existingBranchCount;
  });
}