#!/usr/bin/env bash
# Open a pull request against the Mimic Gitea repository using the credentials
# already stored in ~/.git-credentials (the same token used for `git push`).
#
# Usage:
#   scripts/open-pr.sh --title "feat: sprint N — short summary" \
#                      --body  path/to/body.md \
#                      [--base main] \
#                      [--head <current branch by default>]
#
# Or via the Makefile wrapper:
#   make open-pr TITLE="feat: sprint 4 — UI polish" BODY=tasks/pr-body-sprint-4.md
#
# Output: prints the PR URL on success, exits non-zero on failure.

set -euo pipefail

# --- Arg parsing ------------------------------------------------------------

TITLE=""
BODY_FILE=""
BASE="main"
HEAD=""

while [[ $# -gt 0 ]]; do
  case "$1" in
    --title)
      TITLE="${2:-}"
      shift 2
      ;;
    --body)
      BODY_FILE="${2:-}"
      shift 2
      ;;
    --base)
      BASE="${2:-}"
      shift 2
      ;;
    --head)
      HEAD="${2:-}"
      shift 2
      ;;
    --sprint)
      # purely informational; ignored — the title is what carries semantics
      shift 2
      ;;
    -h|--help)
      sed -n '2,15p' "$0"
      exit 0
      ;;
    *)
      echo "Unknown arg: $1" >&2
      exit 2
      ;;
  esac
done

[[ -n "$TITLE"     ]] || { echo "--title is required" >&2; exit 2; }
[[ -n "$BODY_FILE" ]] || { echo "--body is required"  >&2; exit 2; }
[[ -f "$BODY_FILE" ]] || { echo "body file not found: $BODY_FILE" >&2; exit 2; }

# --- Credentials ------------------------------------------------------------

CRED_FILE="${HOME}/.git-credentials"
[[ -f "$CRED_FILE" ]] || { echo "no ~/.git-credentials — git push must have run at least once" >&2; exit 3; }

# Detect Gitea host from origin remote
ORIGIN_URL=$(git remote get-url origin)
# Strip protocol, .git suffix → host/owner/repo
case "$ORIGIN_URL" in
  https://*)
    REST="${ORIGIN_URL#https://}"
    ;;
  *)
    echo "origin is not https (got: $ORIGIN_URL) — this script supports HTTPS Gitea only" >&2
    exit 3
    ;;
esac
REST="${REST%.git}"
HOST="${REST%%/*}"
PATHPART="${REST#*/}"          # owner/repo
OWNER="${PATHPART%%/*}"
REPO="${PATHPART#*/}"
REPO="${REPO%%/*}"             # belt + braces in case of trailing slash

# Match the credential line for this host
CRED_LINE=$(grep -E "^https://[^@]+@${HOST}\$" "$CRED_FILE" || true)
[[ -n "$CRED_LINE" ]] || { echo "no credential for host ${HOST} in ${CRED_FILE}" >&2; exit 3; }

USER_PART=$(echo "$CRED_LINE" | sed -E 's|^https://([^:]+):.*|\1|')
TOKEN=$(echo "$CRED_LINE" | sed -E 's|^https://[^:]+:([^@]+)@.*$|\1|')

[[ -n "$USER_PART" && -n "$TOKEN" ]] || { echo "could not parse user/token from credential" >&2; exit 3; }

# --- Branch -----------------------------------------------------------------

if [[ -z "$HEAD" ]]; then
  HEAD=$(git rev-parse --abbrev-ref HEAD)
fi
[[ "$HEAD" != "HEAD" ]] || { echo "detached HEAD — pass --head explicitly" >&2; exit 3; }

# --- Compose payload --------------------------------------------------------

API_URL="https://${HOST}/api/v1/repos/${OWNER}/${REPO}/pulls"

PAYLOAD=$(jq -n \
  --arg title "$TITLE" \
  --rawfile body "$BODY_FILE" \
  --arg head "$HEAD" \
  --arg base "$BASE" \
  '{title:$title, body:$body, head:$head, base:$base}')

# --- POST -------------------------------------------------------------------

RESPONSE_FILE=$(mktemp)
HTTP_CODE=$(curl -sS -u "${USER_PART}:${TOKEN}" \
  -H "Content-Type: application/json" \
  -X POST \
  -d "$PAYLOAD" \
  -o "$RESPONSE_FILE" \
  -w "%{http_code}" \
  "$API_URL")

if [[ "$HTTP_CODE" != "201" ]]; then
  echo "PR creation failed (HTTP $HTTP_CODE):" >&2
  jq -r '.message // empty' "$RESPONSE_FILE" >&2 2>/dev/null || cat "$RESPONSE_FILE" >&2
  rm -f "$RESPONSE_FILE"
  exit 4
fi

PR_URL=$(jq -r '.html_url' "$RESPONSE_FILE")
PR_NUMBER=$(jq -r '.number' "$RESPONSE_FILE")
rm -f "$RESPONSE_FILE"

echo "Opened PR #${PR_NUMBER}"
echo "$PR_URL"