#!/usr/bin/env bash
# Adversarial PR review runner.
#
# Fetches a PR's unified diff + metadata from Gitea, asks ONE model to review it
# adversarially, then upserts the result as a single labeled PR comment (so
# re-runs on new commits update the comment in place instead of stacking dupes).
#
# The ollama lane is AGENTIC: it runs the cmd/gadfly Go binary, which drives a
# tool-using agent (majordomo + Ollama Cloud) over the PR's checked-out repo so
# the model can read_file/grep/etc. to VERIFY findings instead of guessing from
# the diff alone. The antigravity lane stays a one-shot `agy` call (agy has its
# own file tools).
#
# Required env:
#   GITEA_API    e.g. https://gitea.stevedudenhoeffer.com/api/v1/repos/steve/mort
#   GITEA_TOKEN  token with repo write access (posts the comment)
#   PR           pull request index/number
#   PROVIDER     "ollama" | "antigravity"
#   MODEL        model id (e.g. qwen3-coder:480b-cloud, gemini-3-pro)
#
# Provider-specific env:
#   ollama:      OLLAMA_CLOUD_API_KEY, GADFLY_BIN (path to the built reviewer),
#                GADFLY_REPO_DIR (checked-out repo; default: this script's repo)
#   antigravity: `agy` on PATH with credentials already seeded (~/.gemini)
#
# Optional:
#   MAX_DIFF_CHARS  diff truncation cap for the prompt (default 60000)
#
# This script is advisory: it never fails the job for review content. It exits
# non-zero only on a usage/configuration error.
set -uo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
MAX_DIFF_CHARS="${MAX_DIFF_CHARS:-60000}"

: "${GITEA_API:?GITEA_API required}"
: "${GITEA_TOKEN:?GITEA_TOKEN required}"
: "${PR:?PR required}"
: "${PROVIDER:?PROVIDER required}"
: "${MODEL:?MODEL required}"

MARKER="<!-- gadfly-review:${PROVIDER}:${MODEL} -->"
say() { echo "[gadfly-review:${PROVIDER}:${MODEL}] $*" >&2; }

# jq is required for payload building / response parsing; install if missing.
if ! command -v jq >/dev/null 2>&1; then
  say "jq not found; attempting install"
  { apt-get update -qq && apt-get install -y -qq jq; } >/dev/null 2>&1 \
    || { sudo apt-get update -qq && sudo apt-get install -y -qq jq; } >/dev/null 2>&1 \
    || { say "could not install jq"; exit 1; }
fi

# curl timeouts: Gitea API calls are quick. Word-split on purpose so the flags
# expand as separate args. (The LLM call's own deadline lives in the reviewer
# binary / agy, not here.)
API_TIMEOUT="--connect-timeout 20 --max-time 30"

# --- fetch PR context -------------------------------------------------------
say "fetching PR #${PR} context"
DIFF="$(curl $API_TIMEOUT -fsS -H "Authorization: token ${GITEA_TOKEN}" "${GITEA_API}/pulls/${PR}.diff" || true)"
META="$(curl $API_TIMEOUT -fsS -H "Authorization: token ${GITEA_TOKEN}" "${GITEA_API}/pulls/${PR}" || echo '{}')"
TITLE="$(echo "$META" | jq -r '.title // ""')"
BODY="$(echo "$META" | jq -r '.body // ""')"

if [ -z "$DIFF" ]; then
  say "empty diff; nothing to review"
  exit 0
fi

# Keep the FULL diff for the agentic (ollama) reviewer — it can pull the whole
# thing via the get_diff tool and embeds a truncated copy in the prompt itself.
# The truncated copy below is only for the one-shot antigravity prompt.
FULL_DIFF="$DIFF"
TRUNC_NOTE=""
if [ "${#DIFF}" -gt "$MAX_DIFF_CHARS" ]; then
  DIFF="${DIFF:0:$MAX_DIFF_CHARS}"
  TRUNC_NOTE=$'\n\n[NOTE: diff truncated to '"${MAX_DIFF_CHARS}"' chars for length; review the rest manually.]'
fi

SYS="$(cat "${SCRIPT_DIR}/system-prompt.txt")"
USR="$(printf 'PR #%s: %s\n\nDescription:\n%s\n\nUnified diff to review:\n```diff\n%s\n```%s' \
  "$PR" "$TITLE" "$BODY" "$DIFF" "$TRUNC_NOTE")"

# --- call the model ---------------------------------------------------------
REVIEW=""
case "$PROVIDER" in
  ollama)
    # Agentic lane: hand off to the cmd/gadfly binary, which runs a tool-using
    # agent over the checked-out repo so it can verify findings instead of
    # guessing from the diff. The workflow builds the binary and exports
    # GADFLY_BIN + GADFLY_REPO_DIR; we fall back to sane defaults for a
    # local run.
    if [ -z "${OLLAMA_CLOUD_API_KEY:-}" ]; then
      REVIEW="⚠️ \`OLLAMA_CLOUD_API_KEY\` is not configured; this reviewer was skipped."
    else
      BIN="${GADFLY_BIN:-gadfly}"
      if ! command -v "$BIN" >/dev/null 2>&1 && [ ! -x "$BIN" ]; then
        REVIEW="⚠️ Agentic reviewer binary not found (\`GADFLY_BIN=${BIN}\`); the workflow build step may have failed."
      else
        REPO_DIR="${GADFLY_REPO_DIR:-$(cd "${SCRIPT_DIR}/../../.." && pwd)}"
        DIFF_FILE="$(mktemp)"
        ERR_FILE="${DIFF_FILE}.err"
        printf '%s' "$FULL_DIFF" > "$DIFF_FILE"
        REVIEW="$(
          OLLAMA_API_KEY="$OLLAMA_CLOUD_API_KEY" \
          GADFLY_MODEL="$MODEL" \
          GADFLY_REPO_DIR="$REPO_DIR" \
          GADFLY_DIFF_FILE="$DIFF_FILE" \
          GADFLY_SYSTEM_FILE="${SCRIPT_DIR}/system-prompt.txt" \
          GADFLY_TITLE="$TITLE" \
          GADFLY_BODY="$BODY" \
          GADFLY_MAX_DIFF_CHARS="$MAX_DIFF_CHARS" \
          "$BIN" 2>"$ERR_FILE"
        )"
        rc=$?
        if [ "$rc" -ne 0 ] || [ -z "$REVIEW" ]; then
          REVIEW="⚠️ Agentic reviewer for \`${MODEL}\` failed (exit ${rc}):
\`\`\`
$(tail -c 1500 "$ERR_FILE" 2>/dev/null)
\`\`\`"
        fi
        rm -f "$DIFF_FILE" "$ERR_FILE"
      fi
    fi
    ;;
  antigravity)
    if ! command -v agy >/dev/null 2>&1; then
      REVIEW="⚠️ Antigravity CLI (\`agy\`) not found on PATH."
    else
      FULL="$(printf '%s\n\n%s' "$SYS" "$USR")"
      if ! REVIEW="$(agy -p "$FULL" --model "$MODEL" 2>agy.err)"; then
        REVIEW="⚠️ Antigravity CLI failed:
\`\`\`
$(tail -c 1500 agy.err 2>/dev/null)
\`\`\`"
      fi
      [ -z "$REVIEW" ] && REVIEW="⚠️ Antigravity CLI returned no output (auth/quota?)."
    fi
    ;;
  *)
    say "unknown provider: ${PROVIDER}"; exit 1 ;;
esac

# --- assemble comment -------------------------------------------------------
COMMENT="$(printf '%s\n### 🔭 Adversarial review — `%s` (%s)\n\n%s\n\n<sub>Automated adversarial review. Advisory only — does not block merge.</sub>' \
  "$MARKER" "$MODEL" "$PROVIDER" "$REVIEW")"
POST_BODY="$(jq -n --arg b "$COMMENT" '{body:$b}')"

# --- upsert by marker -------------------------------------------------------
EXISTING_ID=""
page=1
while [ "$page" -le 10 ]; do
  CMTS="$(curl $API_TIMEOUT -fsS -H "Authorization: token ${GITEA_TOKEN}" \
    "${GITEA_API}/issues/${PR}/comments?limit=50&page=${page}" || echo '[]')"
  [ "$(echo "$CMTS" | jq 'length')" = "0" ] && break
  EXISTING_ID="$(echo "$CMTS" | jq -r --arg m "$MARKER" \
    '.[] | select(.body != null and (.body | startswith($m))) | .id' | head -n1)"
  [ -n "$EXISTING_ID" ] && break
  page=$((page+1))
done

if [ -n "$EXISTING_ID" ]; then
  say "updating existing comment ${EXISTING_ID}"
  curl $API_TIMEOUT -sS -X PATCH -H "Authorization: token ${GITEA_TOKEN}" -H "Content-Type: application/json" \
    "${GITEA_API}/issues/comments/${EXISTING_ID}" -d "$POST_BODY" >/dev/null
else
  say "creating new comment"
  curl $API_TIMEOUT -sS -X POST -H "Authorization: token ${GITEA_TOKEN}" -H "Content-Type: application/json" \
    "${GITEA_API}/issues/${PR}/comments" -d "$POST_BODY" >/dev/null
fi
say "done"