#!/bin/bash
# pr-create.sh - Create pull requests on Gitea or GitHub
# Usage: pr-create.sh -t "Title" [-b "Body"] [-B base] [-H head] [-l "labels"] [-m "milestone"] [--login <name>]
#
# Acting principal is resolved identity-first (#1280): an explicit --login
# wins; otherwise MOSAIC_GIT_IDENTITY / per-worktree git config
# mosaic.gitIdentity selects the principal when a per-slot token exists (and
# the wrapper then creates the PR through the REST API with that identity's
# token — tea is never invoked, so the tea login list cannot shadow the
# requested principal); the tea login list is the LAST resort. A requested
# identity with no per-slot token fails LOUD rather than writing under
# whichever account tea happens to hold.

set -e

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

# Default values
TITLE=""
BODY=""
BASE_BRANCH=""
HEAD_BRANCH=""
LABELS=""
MILESTONE=""
DRAFT=false
ISSUE=""

# get_remote_host, get_gitea_token, get_repo_info, and get_gitea_repo_args are provided by detect-platform.sh

# Acting-principal mode set in the Gitea branch below (from
# resolve_gitea_principal): "login" when --login was given, "identity" when a
# git identity bound, "default" otherwise. PRINCIPAL_MODE=login makes the API
# arm resolve the --login principal's token too, so an explicit --login keeps
# winning even on the tea-FAILURE fallback arm (otherwise the fallback would
# silently re-resolve to the environment identity or shared credential).
PRINCIPAL_MODE=""
PRINCIPAL_NAME=""

gitea_pr_create_api() {
    local host repo token url payload
    host=$(get_remote_host) || {
        echo "Error: could not determine remote host for API fallback" >&2
        return 1
    }
    repo=$(get_repo_info) || {
        echo "Error: could not determine repo owner/name for API fallback" >&2
        return 1
    }
    if [[ "$PRINCIPAL_MODE" == "login" ]]; then
        token=$(get_gitea_token_for_login "$PRINCIPAL_NAME" "$host") || {
            echo "Error: could not resolve a host-matched Gitea token for --login '$PRINCIPAL_NAME' on host '$host' (API path)" >&2
            return 1
        }
    else
        # Identity-first when MOSAIC_GIT_IDENTITY / git config mosaic.gitIdentity
        # is set (per-slot token, fail-loud on absence); shared default otherwise.
        token=$(get_gitea_token "$host") || {
            echo "Error: Gitea token not found for API fallback (set GITEA_TOKEN or configure ~/.git-credentials)" >&2
            return 1
        }
    fi

    if [[ -n "$LABELS" || -n "$MILESTONE" || "$DRAFT" == true ]]; then
        echo "Warning: API fallback applies title/body/head/base only; labels/milestone/draft require authenticated tea setup." >&2
    fi

    payload=$(TITLE="$TITLE" BODY="$BODY" HEAD_BRANCH="$HEAD_BRANCH" BASE_BRANCH="$BASE_BRANCH" python3 - <<'PY'
import json
import os

payload = {
    "title": os.environ["TITLE"],
    "head": os.environ["HEAD_BRANCH"],
    "base": os.environ["BASE_BRANCH"] or "main",
}
body = os.environ.get("BODY", "")
if body:
    payload["body"] = body
print(json.dumps(payload))
PY
)

    url="https://${host}/api/v1/repos/${repo}/pulls"
    curl -fsS -X POST \
      -H "User-Agent: curl/8" \
      -H "Authorization: token ${token}" \
      -H "Content-Type: application/json" \
      -d "$payload" \
      "$url"
}

usage() {
    cat <<EOF
Usage: $(basename "$0") [OPTIONS]

Create a pull request on the current repository (Gitea or GitHub).

Options:
    -t, --title TITLE       PR title (required, or use --issue)
    -b, --body BODY         PR description/body
    -B, --base BRANCH       Base branch to merge into (default: main/master)
    -H, --head BRANCH       Head branch with changes (default: current branch)
    -l, --labels LABELS     Comma-separated labels
    -m, --milestone NAME    Milestone name
        --login NAME        Act as this Gitea tea login (wins over MOSAIC_GIT_IDENTITY)
    -i, --issue NUMBER      Link to issue (auto-generates title if not provided)
    -d, --draft             Create as draft PR
    -h, --help              Show this help message

Examples:
    $(basename "$0") -t "Add login feature" -b "Implements user authentication"
    $(basename "$0") -t "Fix bug" -B main -H feature/fix-123
    $(basename "$0") -i 42 -b "Implements the feature described in #42"
    $(basename "$0") -t "WIP: New feature" --draft
EOF
    exit "${1:-1}"
}

# Parse arguments
while [[ $# -gt 0 ]]; do
    case $1 in
        -t|--title)
            TITLE="$2"
            shift 2
            ;;
        -b|--body)
            BODY="$2"
            shift 2
            ;;
        -B|--base)
            BASE_BRANCH="$2"
            shift 2
            ;;
        -H|--head)
            HEAD_BRANCH="$2"
            shift 2
            ;;
        -l|--labels)
            LABELS="$2"
            shift 2
            ;;
        -m|--milestone)
            MILESTONE="$2"
            shift 2
            ;;
        --login)
            LOGIN_OVERRIDE="$2"
            shift 2
            ;;
        -i|--issue)
            ISSUE="$2"
            shift 2
            ;;
        -d|--draft)
            DRAFT=true
            shift
            ;;
        -h|--help)
            usage 0
            ;;
        *)
            echo "Unknown option: $1" >&2
            usage
            ;;
    esac
done

# If no title but issue provided, generate title
if [[ -z "$TITLE" ]] && [[ -n "$ISSUE" ]]; then
    TITLE="Fixes #$ISSUE"
fi

if [[ -z "$TITLE" ]]; then
    echo "Error: Title is required (-t) or provide an issue (-i)" >&2
    usage
fi

# Default head branch to current branch
if [[ -z "$HEAD_BRANCH" ]]; then
    HEAD_BRANCH=$(git branch --show-current)
fi

# Add issue reference to body if provided
if [[ -n "$ISSUE" ]]; then
    if [[ -n "$BODY" ]]; then
        BODY="$BODY

Fixes #$ISSUE"
    else
        BODY="Fixes #$ISSUE"
    fi
fi

PLATFORM=$(detect_platform)

case "$PLATFORM" in
    github)
        CMD=(gh pr create --title "$TITLE")
        [[ -n "$BODY" ]] && CMD+=(--body "$BODY")
        [[ -n "$BASE_BRANCH" ]] && CMD+=(--base "$BASE_BRANCH")
        [[ -n "$HEAD_BRANCH" ]] && CMD+=(--head "$HEAD_BRANCH")
        [[ -n "$LABELS" ]] && CMD+=(--label "$LABELS")
        [[ -n "$MILESTONE" ]] && CMD+=(--milestone "$MILESTONE")
        [[ "$DRAFT" == true ]] && CMD+=(--draft)
        "${CMD[@]}"
        ;;
    gitea)
        # Resolve the acting principal identity-first (#1280). The tea login
        # list is the LAST resort: it knows nothing about which seat is calling,
        # and a login resolved from it first is what attributed PRs to the wrong
        # account even when MOSAIC_GIT_IDENTITY was set.
        principal_host=$(get_remote_host 2>/dev/null || true)
        if ! principal_resolved="$(resolve_gitea_principal "${LOGIN_OVERRIDE:-}" "$principal_host")"; then
            # resolve_gitea_principal already printed the fail-loud diagnostic.
            exit 1
        fi
        PRINCIPAL_MODE="$(printf '%s' "$principal_resolved" | cut -f1)"
        PRINCIPAL_NAME="$(printf '%s' "$principal_resolved" | cut -f2)"

        if [[ "$PRINCIPAL_MODE" == "identity" ]]; then
            # HAPPY PATH for a requested identity: the per-slot token IS the
            # credential, so create through the REST API directly and never
            # invoke tea — the identity arm must be REACHED, not sit behind a
            # tea failure (#1280). Fail-loud on a missing slot already happened
            # in resolve_gitea_principal.
            gitea_pr_create_api
            exit $?
        fi

        # tea pull create syntax. Always pass --repo because tea repo inference
        # is unreliable in Mosaic worktrees/profile shells. Use arrays instead
        # of eval so markdown backticks/body content are not shell-executed.
        REPO_SLUG=$(get_repo_slug)
        if [[ "$PRINCIPAL_MODE" == "login" ]]; then
            GITEA_LOGIN_NAME="$PRINCIPAL_NAME"
        else
            GITEA_LOGIN_NAME=$(get_gitea_login) || {
                echo "Warning: could not resolve Gitea login for tea; trying Gitea API fallback..." >&2
                gitea_pr_create_api
                exit $?
            }
        fi
        if ! get_gitea_authenticated_user "$GITEA_LOGIN_NAME" >/dev/null; then
            echo "Warning: Tea authenticated-user validation failed (possible stale user/login); trying Gitea API fallback..." >&2
            gitea_pr_create_api
            exit $?
        fi
        REPO_ARGS=(--repo "$REPO_SLUG" --login "$GITEA_LOGIN_NAME")
        CMD=(tea pr create "${REPO_ARGS[@]}" --title "$TITLE")
        [[ -n "$BODY" ]] && CMD+=(--description "$BODY")
        [[ -n "$BASE_BRANCH" ]] && CMD+=(--base "$BASE_BRANCH")
        [[ -n "$HEAD_BRANCH" ]] && CMD+=(--head "$HEAD_BRANCH")

        # Handle labels for tea
        if [[ -n "$LABELS" ]]; then
            # tea may use --labels flag
            CMD+=(--labels "$LABELS")
        fi

        # Handle milestone for tea
        if [[ -n "$MILESTONE" ]]; then
            MILESTONE_ID=$(tea milestones list "${REPO_ARGS[@]}" 2>/dev/null | grep -E "^\s*[0-9]+" | grep "$MILESTONE" | awk '{print $1}' | head -1)
            if [[ -n "$MILESTONE_ID" ]]; then
                CMD+=(--milestone "$MILESTONE_ID")
            else
                echo "Warning: Could not find milestone '$MILESTONE', creating without milestone" >&2
            fi
        fi

        # Note: tea may not support --draft flag in all versions
        if [[ "$DRAFT" == true ]]; then
            echo "Note: Draft PR may not be supported by your tea version" >&2
        fi

        if "${CMD[@]}"; then
            exit 0
        fi
        echo "Warning: tea pr create failed, trying Gitea API fallback..." >&2
        gitea_pr_create_api
        ;;
    *)
        echo "Error: Could not detect git platform" >&2
        exit 1
        ;;
esac