#!/bin/bash
# pr-close.sh - Close a pull request without merging on GitHub or Gitea
# Usage: pr-close.sh -n <pr_number> [-b <comment>]
# (-c/--comment is a backward-compatible alias for -b/--body; R1/R4 2026-08-28)

set -e

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/detect-platform.sh"

# Parse arguments
PR_NUMBER=""
COMMENT=""
BODY_FILE=""

# Usage-error contract (R4, 2026-08-28): usage errors print to STDERR and exit 2,
# distinct from provider, credential, and verification failures (exit 1), so a
# caller or stop gate can tell an invocation defect from a delivery blocker.
usage_error() {
    echo "Error: $*" >&2
    echo "Usage: pr-close.sh -n <pr_number> [-b <comment>] (see --help)" >&2
    exit 2
}

while [[ $# -gt 0 ]]; do
    case $1 in
        -n|--number)
            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
            PR_NUMBER="$2"
            shift 2
            ;;
        -b|--body|-c|--comment)
            # R1 (2026-08-28): --body is the canonical flag; -c/--comment stays
            # a backward-compatible alias.
            [[ $# -ge 2 && "$2" != - && "$2" != --* && ! "$2" =~ ^-[[:alnum:]] ]] || usage_error "option $1 requires a value (option-like values are rejected; bare - is reserved)"
            COMMENT="$2"
            shift 2
            ;;
        --body-file)
            # R3: body from file (or '-' = stdin); mutually exclusive with --body.
            [[ $# -ge 2 && "$2" != --* ]] || usage_error "option $1 requires a path (or - for stdin)"
            BODY_FILE="$2"
            shift 2
            ;;
        -h|--help)
            echo "Usage: pr-close.sh -n <pr_number> [-b <comment>]"
            echo ""
            echo "Options:"
            echo "  -n, --number   PR number (required)"
            echo "  -b, --body     Comment before closing (optional; canonical)"
            echo "  -c, --comment  Alias for --body"
            echo "  -h, --help     Show this help"
            echo ""
            echo "Exit codes: 0 success; 2 usage error (stderr); 1 provider/credential/verification failure."
            exit 0
            ;;
        *)
            usage_error "unknown option: $1"
            ;;
    esac
done

# R3 (2026-08-29): resolve --body-file into COMMENT (file or stdin '-');
# exclusive with an explicit --body/--comment value.
if [[ -n "$BODY_FILE" ]]; then
    [[ -z "$COMMENT" ]] || usage_error "--body-file and --body are mutually exclusive"
    if [[ "$BODY_FILE" == "-" ]]; then
        COMMENT=$(cat) || usage_error "could not read body from stdin"
    else
        [[ -r "$BODY_FILE" ]] || usage_error "body file not readable: $BODY_FILE"
        COMMENT=$(cat "$BODY_FILE") || usage_error "could not read body file: $BODY_FILE"
    fi
fi


if [[ -z "$PR_NUMBER" ]]; then
    usage_error "PR number is required (-n/--number)"
fi

detect_platform >/dev/null

if [[ "$PLATFORM" == "github" ]]; then
    # R4: normalize provider failures to exit 1 (gh's own usage errors exit 2
    # and would collide with the reserved usage-error status).
    if [[ -n "$COMMENT" ]]; then
        gh_rc=0
        gh pr comment "$PR_NUMBER" --body "$COMMENT" || gh_rc=$?
        if [[ "$gh_rc" -ne 0 ]]; then
            echo "Error: GitHub PR comment before close failed (gh exit $gh_rc)" >&2
            exit 1
        fi
    fi
    gh_rc=0
    gh pr close "$PR_NUMBER" || gh_rc=$?
    if [[ "$gh_rc" -ne 0 ]]; then
        echo "Error: GitHub PR close failed (gh exit $gh_rc)" >&2
        exit 1
    fi
    echo "Closed GitHub PR #$PR_NUMBER"
elif [[ "$PLATFORM" == "gitea" ]]; then
    if [[ -n "$COMMENT" ]]; then
        prov_rc=0
        tea pr comment "$PR_NUMBER" "$COMMENT" $(get_gitea_repo_args) || prov_rc=$?
        [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
    fi
    prov_rc=0
    tea pr close "$PR_NUMBER" $(get_gitea_repo_args) || prov_rc=$?
    [[ "$prov_rc" -eq 0 ]] || { echo "Error: provider command failed (exit ${prov_rc}; provider failure, not a usage error)" >&2; exit 1; }
    echo "Closed Gitea PR #$PR_NUMBER"
else
    echo "Error: Unknown platform"
    exit 1
fi