GenChangelogs.hs

#!/usr/bin/env cabal
{- cabal:
build-depends: base, process, text, github, time
-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}

import Control.Monad
import Data.List
import Data.Maybe
import qualified Data.Text as T
import Data.Time.Format.ISO8601
import Data.Time.LocalTime
import GitHub
import System.Process

main :: IO ()
main = do
  callCommand "git fetch --tags"
  tags <-
    filter (isPrefixOf "0.") . lines
      <$> readProcess "git" ["tag", "--list", "--sort=v:refname"] ""

  lastDateStr <- last . lines <$> readProcess "git" ["show", "-s", "--format=%cI", "-1", last tags] ""
  lastDate <- zonedTimeToUTC <$> iso8601ParseM lastDateStr

  prs <- github' $ pullRequestsForR "skykanin" "DraftGen" stateClosed FetchAll
  let prsAfterLastTag =
        either
          (error . show)
          (foldMap (\pr -> [pr | inRange pr]))
          prs
      inRange pr
        | Just mergedDate <- simplePullRequestMergedAt pr = mergedDate > lastDate
        | otherwise = False

  forM_ prsAfterLastTag $ \SimplePullRequest {..} ->
    putStrLn $
      T.unpack $
        "- "
          <> simplePullRequestTitle
          <> "\n([#"
          <> T.pack (show $ unIssueNumber simplePullRequestNumber)
          <> "]("
          <> getUrl simplePullRequestHtmlUrl
          <> "))"
          <> " by @"
          <> untagName (simpleUserLogin simplePullRequestUser)