#!/usr/bin/env bash
set -euo pipefail

# Массовая миграция репозиториев GitHub -> Gitea.
# Переносит всю git-историю через mirror push. Может переносить LFS (опционально).
#
# Пуш в Gitea: PUSH_WITH_SSH=true — нужен SSH-ключ на ЭТОЙ машине (добавлен в Gitea).
# На сервере без ключа — PUSH_WITH_SSH=false и GITEA_USERNAME + GITEA_TOKEN (HTTPS).
#
# Только выбранные репозитории (вместо полного списка с GitHub):
#   GITHUB_REPOS="owner/repo1,owner/repo2"
# и/или
#   GITHUB_REPOS_FILE=/path/to/list.txt   # по одному owner/repo на строку, # — комментарий

: "${GITHUB_TOKEN:?Set GITHUB_TOKEN}"
: "${GITHUB_OWNER:?Set GITHUB_OWNER (user or org on GitHub)}"
: "${GITHUB_OWNER_TYPE:?Set GITHUB_OWNER_TYPE=user|org}"

: "${GITEA_URL:?Set GITEA_URL, e.g. https://git.papatramp.ru}"
: "${GITEA_TOKEN:?Set GITEA_TOKEN (Gitea PAT)}"
: "${GITEA_OWNER:?Set GITEA_OWNER (target user/org in Gitea)}"
: "${GITEA_OWNER_TYPE:?Set GITEA_OWNER_TYPE=user|org}"

WORKDIR="${WORKDIR:-$PWD/migration-workdir}"
PUSH_WITH_SSH="${PUSH_WITH_SSH:-true}"     # true/false
GITEA_SSH_HOST="${GITEA_SSH_HOST:-git.papatramp.ru}"
GITEA_SSH_PORT="${GITEA_SSH_PORT:-2222}"
MIGRATE_LFS="${MIGRATE_LFS:-false}"        # true/false
# См. шапку: если задано — мигрируются только эти репозитории (полный вид owner/name).
GITHUB_REPOS="${GITHUB_REPOS:-}"
GITHUB_REPOS_FILE="${GITHUB_REPOS_FILE:-}"

mkdir -p "$WORKDIR"

need_cmd() { command -v "$1" >/dev/null 2>&1 || { echo "Missing command: $1"; exit 1; }; }
need_cmd curl
need_cmd jq
need_cmd git

if [[ "$MIGRATE_LFS" == "true" ]]; then
  need_cmd git-lfs
fi

gh_api() {
  local url="$1"
  curl -fsSL \
    -H "Authorization: Bearer $GITHUB_TOKEN" \
    -H "Accept: application/vnd.github+json" \
    "$url"
}

gitea_api() {
  local method="$1"
  local url="$2"
  local data="${3:-}"
  if [[ -n "$data" ]]; then
    curl -sS -o /tmp/gitea_resp.json -w "%{http_code}" \
      -X "$method" \
      -H "Authorization: token $GITEA_TOKEN" \
      -H "Content-Type: application/json" \
      -d "$data" \
      "$url"
  else
    curl -sS -o /tmp/gitea_resp.json -w "%{http_code}" \
      -X "$method" \
      -H "Authorization: token $GITEA_TOKEN" \
      "$url"
  fi
}

create_gitea_repo_if_needed() {
  local repo_name="$1"
  local private="$2"
  local payload endpoint code

  payload="$(jq -n --arg name "$repo_name" --argjson private "$private" \
    '{name:$name, private:$private, auto_init:false}')"

  if [[ "$GITEA_OWNER_TYPE" == "org" ]]; then
    endpoint="$GITEA_URL/api/v1/orgs/$GITEA_OWNER/repos"
  else
    endpoint="$GITEA_URL/api/v1/user/repos"
  fi

  code="$(gitea_api POST "$endpoint" "$payload")"
  if [[ "$code" == "201" ]]; then
    echo "  [OK] Created: $GITEA_OWNER/$repo_name"
  elif [[ "$code" == "409" ]]; then
    echo "  [SKIP] Exists: $GITEA_OWNER/$repo_name"
  else
    echo "  [ERR] Create repo failed: HTTP $code"
    cat /tmp/gitea_resp.json
    return 1
  fi
}

push_mirror() {
  local mirror_dir="$1"
  local repo_name="$2"
  local remote_url

  if [[ "$PUSH_WITH_SSH" == "true" ]]; then
    remote_url="ssh://git@${GITEA_SSH_HOST}:${GITEA_SSH_PORT}/${GITEA_OWNER}/${repo_name}.git"
  else
    : "${GITEA_USERNAME:?Set GITEA_USERNAME when PUSH_WITH_SSH=false}"
    remote_url="https://${GITEA_USERNAME}:${GITEA_TOKEN}@${GITEA_URL#https://}/${GITEA_OWNER}/${repo_name}.git"
  fi

  if git -C "$mirror_dir" remote | grep -q '^gitea$'; then
    git -C "$mirror_dir" remote set-url gitea "$remote_url"
  else
    git -C "$mirror_dir" remote add gitea "$remote_url"
  fi

  git -C "$mirror_dir" push --mirror gitea
}

migrate_repo() {
  local full_name="$1"
  local private="$2"
  local repo_name="${full_name##*/}"
  local mirror_dir="$WORKDIR/${repo_name}.git"

  echo "=== $full_name (private=$private) ==="
  rm -rf "$mirror_dir"

  # GitHub HTTPS + PAT: способ через Authorization header иногда ломается из‑за credential.helper /
  # старых версий Git. Способ oauth2:<token>@github.com поддерживается GitHub для PAT и fine-grained.
  # credential.helper= отключает подмешивание сохранённых логинов к github.com.
  GIT_TERMINAL_PROMPT=0 git -c credential.helper= clone --mirror \
    "https://oauth2:${GITHUB_TOKEN}@github.com/${full_name}.git" "$mirror_dir"

  create_gitea_repo_if_needed "$repo_name" "$private"
  push_mirror "$mirror_dir" "$repo_name"

  if [[ "$MIGRATE_LFS" == "true" ]]; then
    git -C "$mirror_dir" lfs fetch --all || true
    git -C "$mirror_dir" lfs push --all gitea || true
  fi

  echo "  [DONE] $full_name"
}

migrate_repo_from_github_api() {
  local full_name="$1"
  local repo_json private
  repo_json="$(gh_api "https://api.github.com/repos/${full_name}")"
  if ! echo "$repo_json" | jq -e '.full_name' >/dev/null 2>&1; then
    echo "[ERR] Репозиторий недоступен или не найден на GitHub: ${full_name}"
    echo "$repo_json" | jq -r '.message // .' 2>/dev/null || echo "$repo_json"
    exit 1
  fi
  private="$(echo "$repo_json" | jq -r '.private')"
  migrate_repo "$full_name" "$private"
}

migrate_selected_repos() {
  local names=() line part
  if [[ -n "$GITHUB_REPOS_FILE" ]]; then
    if [[ ! -f "$GITHUB_REPOS_FILE" ]]; then
      echo "[ERR] GITHUB_REPOS_FILE не найден: $GITHUB_REPOS_FILE"
      exit 1
    fi
    while IFS= read -r line || [[ -n "$line" ]]; do
      line="${line%%#*}"
      line="$(echo "$line" | xargs)"
      [[ -z "$line" ]] && continue
      names+=("$line")
    done <"$GITHUB_REPOS_FILE"
  fi
  if [[ -n "$GITHUB_REPOS" ]]; then
    local -a repo_parts
    IFS=',' read -ra repo_parts <<<"${GITHUB_REPOS}"
    for part in "${repo_parts[@]}"; do
      part="$(echo "$part" | xargs)"
      [[ -z "$part" ]] && continue
      names+=("$part")
    done
  fi

  if [[ "${#names[@]}" -eq 0 ]]; then
    echo "[ERR] Указаны GITHUB_REPOS / GITHUB_REPOS_FILE, но список имён пуст."
    exit 1
  fi

  echo "[INFO] Режим выборочной миграции, репозиториев: ${#names[@]}"

  local fn
  for fn in "${names[@]}"; do
    if [[ "$fn" != */* ]]; then
      echo "[ERR] Ожидается полное имя owner/repo, получено: $fn"
      exit 1
    fi
    migrate_repo_from_github_api "$fn"
  done

  echo "Выбранные репозитории обработаны."
}

main() {
  if [[ -n "$GITHUB_REPOS" || -n "$GITHUB_REPOS_FILE" ]]; then
    migrate_selected_repos
    return 0
  fi

  local page=1
  local per_page=100
  local url repos_json count

  while true; do
    if [[ "$GITHUB_OWNER_TYPE" == "org" ]]; then
      url="https://api.github.com/orgs/${GITHUB_OWNER}/repos?type=all&per_page=${per_page}&page=${page}"
    else
      url="https://api.github.com/users/${GITHUB_OWNER}/repos?type=owner&per_page=${per_page}&page=${page}"
    fi

    repos_json="$(gh_api "$url")"
    count="$(echo "$repos_json" | jq 'length')"
    [[ "$count" -eq 0 ]] && break

    while IFS=$'\t' read -r full_name private; do
      migrate_repo "$full_name" "$private"
    done < <(echo "$repos_json" | jq -r '.[] | [.full_name, .private] | @tsv')

    ((page++))
  done

  echo "All repositories migrated."
}

main