name: Migrate contributions to Gitea

on:
    issues:
        types: [opened, reopened]
    pull_request_target:
        types: [opened, reopened]

permissions:
    contents: read
    issues: write
    pull-requests: write

concurrency:
    group: migrate-${{ github.event_name }}-${{ github.event.issue.number || github.event.pull_request.number }}

env:
    GITEA_API_URL: https://git.lechner-systems.at/api/v1
    GITEA_REPOSITORY: FrauJulian/Discord-Audio-Stream
    GITEA_REPOSITORY_URL: https://git.lechner-systems.at/FrauJulian/Discord-Audio-Stream.git

jobs:
    migrate:
        runs-on: ubuntu-latest
        steps:
            - name: Migrate and close
              env:
                  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
                  GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
              run: |
                  set -euo pipefail

                  if [ "$GITHUB_EVENT_NAME" = "issues" ]; then
                      kind=issue
                      number="$(jq -r '.issue.number' "$GITHUB_EVENT_PATH")"
                      title="$(jq -r '.issue.title' "$GITHUB_EVENT_PATH")"
                      body="$(jq -r '.issue.body // ""' "$GITHUB_EVENT_PATH")"
                      author="$(jq -r '.issue.user.login' "$GITHUB_EVENT_PATH")"
                      source_url="$(jq -r '.issue.html_url' "$GITHUB_EVENT_PATH")"
                  else
                      kind=pull
                      number="$(jq -r '.pull_request.number' "$GITHUB_EVENT_PATH")"
                      title="$(jq -r '.pull_request.title' "$GITHUB_EVENT_PATH")"
                      body="$(jq -r '.pull_request.body // ""' "$GITHUB_EVENT_PATH")"
                      author="$(jq -r '.pull_request.user.login' "$GITHUB_EVENT_PATH")"
                      source_url="$(jq -r '.pull_request.html_url' "$GITHUB_EVENT_PATH")"
                  fi

                  github_api="${GITHUB_API_URL}/repos/${GITHUB_REPOSITORY}"
                  migrated_url="$(
                      curl --fail --silent --show-error \
                          --header "Authorization: Bearer ${GITHUB_TOKEN}" \
                          --header "Accept: application/vnd.github+json" \
                          "${github_api}/issues/${number}/comments?per_page=100" |
                          jq -r '[.[] | select(.user.login == "github-actions[bot]" and (.body | startswith("Migrated to Gitea: ")))] | first | .body // "" | sub("^Migrated to Gitea: "; "")'
                  )"

                  if [ -z "$migrated_url" ]; then
                      migrated_body="${body}

                  ---
                  Originally opened by @${author} on GitHub: ${source_url}"

                      if [ "$kind" = issue ]; then
                          jq -n \
                              --arg title "$title" \
                              --arg body "$migrated_body" \
                              '{title: $title, body: $body}' > gitea-request.json

                          curl --fail-with-body \
                              --request POST \
                              --header "Authorization: token ${GITEA_TOKEN}" \
                              --header "Content-Type: application/json" \
                              --data @gitea-request.json \
                              "${GITEA_API_URL}/repos/${GITEA_REPOSITORY}/issues" > gitea-response.json
                      else
                          branch="github-pr-${number}"
                          github_auth="$(printf 'x-access-token:%s' "$GITHUB_TOKEN" | base64 | tr -d '\r\n')"
                          gitea_user="${GITEA_REPOSITORY%%/*}"
                          gitea_auth="$(printf '%s:%s' "$gitea_user" "$GITEA_TOKEN" | base64 | tr -d '\r\n')"

                          git init --quiet migrated-pr
                          cd migrated-pr
                          git -c "http.extraHeader=Authorization: Basic ${github_auth}" fetch \
                              --quiet --depth=1 \
                              "https://github.com/${GITHUB_REPOSITORY}.git" \
                              "refs/pull/${number}/head"
                          git -c "http.extraHeader=Authorization: Basic ${gitea_auth}" push \
                              --quiet --force \
                              "$GITEA_REPOSITORY_URL" \
                              "FETCH_HEAD:refs/heads/${branch}"
                          cd ..

                          base="$(jq -r '.pull_request.base.ref' "$GITHUB_EVENT_PATH")"
                          jq -n \
                              --arg head "$branch" \
                              --arg base "$base" \
                              --arg title "$title" \
                              --arg body "$migrated_body" \
                              '{head: $head, base: $base, title: $title, body: $body}' > gitea-request.json

                          curl --fail-with-body \
                              --request POST \
                              --header "Authorization: token ${GITEA_TOKEN}" \
                              --header "Content-Type: application/json" \
                              --data @gitea-request.json \
                              "${GITEA_API_URL}/repos/${GITEA_REPOSITORY}/pulls" > gitea-response.json
                      fi

                      migrated_url="$(jq -r '.html_url' gitea-response.json)"
                      jq -n --arg body "Migrated to Gitea: ${migrated_url}" '{body: $body}' > github-comment.json
                      curl --fail-with-body \
                          --request POST \
                          --header "Authorization: Bearer ${GITHUB_TOKEN}" \
                          --header "Content-Type: application/json" \
                          --data @github-comment.json \
                          "${github_api}/issues/${number}/comments"
                  fi

                  if [ "$kind" = issue ]; then
                      printf '%s' '{"state":"closed","state_reason":"not_planned"}' > github-close.json
                      close_url="${github_api}/issues/${number}"
                  else
                      printf '%s' '{"state":"closed"}' > github-close.json
                      close_url="${github_api}/pulls/${number}"
                  fi

                  curl --fail-with-body \
                      --request PATCH \
                      --header "Authorization: Bearer ${GITHUB_TOKEN}" \
                      --header "Content-Type: application/json" \
                      --data @github-close.json \
                      "$close_url"