#!/usr/bin/env bash
# claude-vllm — run Claude Code against the homelab LLM gateway instead of api.anthropic.com.
#
# The gateway (LiteLLM in front of vLLM) already speaks the Anthropic Messages
# API on /v1/messages, so no bridge or translation layer is needed — Claude Code
# talks to it directly once ANTHROPIC_BASE_URL points there. This script exists
# only to find the endpoint, credential and model you have already configured
# for another agent, instead of making you paste four exports every time.
#
# Discovery order (first hit wins, per field):
#   1. environment already set (ANTHROPIC_BASE_URL / ANTHROPIC_AUTH_TOKEN / ANTHROPIC_MODEL)
#   2. flags (--provider, --model)
#   3. ~/.pi/agent        settings.json + models.json + auth.json
#   4. ~/.prime/agent     settings.json + models.json + auth.json
#   5. ~/.config/opencode/opencode.jsonc   (provider.<name>.options.{baseURL,apiKey})
#
# Usage:
#   claude-vllm                      # default provider + model, then exec claude
#   claude-vllm --model deepseek-v4-max
#   claude-vllm --provider itaz --model deepseek-v4-fast -- -p "summarise this repo"
#   claude-vllm --list               # show discoverable providers/models and exit
#   claude-vllm --print-env          # print the exports and exit (don't run claude)
set -euo pipefail

PROVIDER=""
MODEL=""
LIST=0
PRINT_ENV=0
CLAUDE_ARGS=()

while [ $# -gt 0 ]; do
  case "$1" in
    --provider) PROVIDER="${2:?--provider needs a value}"; shift 2 ;;
    --model)    MODEL="${2:?--model needs a value}"; shift 2 ;;
    --list)     LIST=1; shift ;;
    --print-env) PRINT_ENV=1; shift ;;
    -h|--help)  sed -n '2,25p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
    --)         shift; CLAUDE_ARGS+=("$@"); break ;;
    *)          CLAUDE_ARGS+=("$1"); shift ;;
  esac
done

command -v jq >/dev/null || { echo "claude-vllm: jq is required" >&2; exit 1; }

PI_HOME="${PI_AGENT_HOME:-$HOME/.pi/agent}"
PRIME_HOME="${PRIME_AGENT_HOME:-$HOME/.prime/agent}"
OC_CONFIG="${XDG_CONFIG_HOME:-$HOME/.config}/opencode/opencode.jsonc"

# jq tolerates the // comments opencode.jsonc may contain only after we strip
# them; harmless for strict JSON.
read_json() { [ -f "$1" ] && sed 's://[^"]*$::' "$1" | jq -c . 2>/dev/null || echo '{}'; }

# ── discover ─────────────────────────────────────────────────────────────────
# Each agent home is tried in turn; the first one that yields a base URL wins,
# and the credential is taken from that same home so we never pair one gateway's
# URL with another's key.
discover_from_agent_home() {
  local home="$1" settings models auth provider base key model
  settings=$(read_json "$home/settings.json")
  models=$(read_json "$home/models.json")
  auth=$(read_json "$home/auth.json")

  provider="$PROVIDER"
  [ -n "$provider" ] || provider=$(jq -r '.defaultProvider // empty' <<<"$settings")
  [ -n "$provider" ] || return 1

  base=$(jq -r --arg p "$provider" '.providers[$p].baseUrl // empty' <<<"$models")
  [ -n "$base" ] || return 1
  # `apiKey` in models.json names an env var; the secret itself lives in auth.json.
  key=$(jq -r --arg p "$provider" '.[$p].key // empty' <<<"$auth")

  model="$MODEL"
  [ -n "$model" ] || model=$(jq -r '.defaultModel // empty' <<<"$settings")

  FOUND_PROVIDER="$provider"; FOUND_BASE="$base"; FOUND_KEY="$key"; FOUND_MODEL="$model"
  FOUND_MODELS=$(jq -r --arg p "$provider" '.providers[$p].models[]?.id' <<<"$models")
  FOUND_CONTEXT=$(jq -r --arg p "$provider" --arg m "$model" \
    '.providers[$p].models[]? | select(.id==$m) | .contextWindow // empty' <<<"$models")
  FOUND_SOURCE="$home"
  return 0
}

discover_from_opencode() {
  local cfg provider base key
  cfg=$(read_json "$OC_CONFIG")
  provider="$PROVIDER"
  if [ -z "$provider" ]; then
    provider=$(jq -r '(.model // "") | split("/")[0] // empty' <<<"$cfg")
  fi
  [ -n "$provider" ] || return 1
  base=$(jq -r --arg p "$provider" '.provider[$p].options.baseURL // empty' <<<"$cfg")
  [ -n "$base" ] || return 1
  key=$(jq -r --arg p "$provider" '.provider[$p].options.apiKey // empty' <<<"$cfg")

  FOUND_PROVIDER="$provider"; FOUND_BASE="$base"; FOUND_KEY="$key"
  FOUND_MODEL="${MODEL:-$(jq -r '(.model // "") | split("/")[1] // empty' <<<"$cfg")}"
  FOUND_MODELS=$(jq -r --arg p "$provider" '.provider[$p].models | keys[]?' <<<"$cfg")
  FOUND_CONTEXT=$(jq -r --arg p "$provider" --arg m "$FOUND_MODEL" \
    '.provider[$p].models[$m].limit.context // empty' <<<"$cfg")
  FOUND_SOURCE="$OC_CONFIG"
  return 0
}

FOUND_PROVIDER=""; FOUND_BASE=""; FOUND_KEY=""; FOUND_MODEL=""; FOUND_MODELS=""; FOUND_CONTEXT=""; FOUND_SOURCE=""
discover_from_agent_home "$PI_HOME" \
  || discover_from_agent_home "$PRIME_HOME" \
  || discover_from_opencode \
  || true

BASE="${ANTHROPIC_BASE_URL:-$FOUND_BASE}"
KEY="${ANTHROPIC_AUTH_TOKEN:-${ANTHROPIC_API_KEY:-$FOUND_KEY}}"
MODEL_ID="${MODEL:-${ANTHROPIC_MODEL:-$FOUND_MODEL}}"

if [ "$LIST" = 1 ]; then
  echo "provider: ${FOUND_PROVIDER:-<none found>}   (from ${FOUND_SOURCE:-nowhere})"
  echo "endpoint: ${BASE:-<none found>}"
  echo "credential: $([ -n "$KEY" ] && echo "found (${KEY:0:10}…)" || echo "<none found>")"
  echo "default model: ${MODEL_ID:-<none>}${FOUND_CONTEXT:+  (context ${FOUND_CONTEXT})}"
  echo "models:"
  [ -n "$FOUND_MODELS" ] && printf '  %s\n' $FOUND_MODELS || echo "  <none listed>"
  exit 0
fi

if [ -z "$BASE" ]; then
  echo "claude-vllm: no LLM endpoint found." >&2
  echo "  Looked in $PI_HOME, $PRIME_HOME and $OC_CONFIG." >&2
  echo "  Set ANTHROPIC_BASE_URL, or configure a provider in one of those." >&2
  exit 1
fi
if [ -z "$KEY" ]; then
  echo "claude-vllm: found $BASE but no credential for '${FOUND_PROVIDER}'." >&2
  echo "  Set ANTHROPIC_AUTH_TOKEN, or add the key to ${FOUND_SOURCE}/auth.json." >&2
  exit 1
fi

# Claude Code appends /v1/messages itself, so the stored provider baseUrl's
# trailing /v1 (an OpenAI-style base) has to come off or requests go to
# /v1/v1/messages.
BASE="${BASE%/}"; BASE="${BASE%/v1}"

export ANTHROPIC_BASE_URL="$BASE"
# ANTHROPIC_AUTH_TOKEN only. Setting ANTHROPIC_API_KEY as well makes Claude Code
# warn that "auth may not work as expected" — it wants exactly one. AUTH_TOKEN
# is the right one for a third-party gateway (sent as `Authorization: Bearer`),
# and an inherited ANTHROPIC_API_KEY would otherwise take precedence over it, so
# clear it for the child process.
export ANTHROPIC_AUTH_TOKEN="$KEY"
unset ANTHROPIC_API_KEY
[ -n "$MODEL_ID" ] && export ANTHROPIC_MODEL="$MODEL_ID"
# Without a substitute, the background/summarisation calls ask the gateway for a
# real Haiku it does not serve, and every one of them 404s.
export ANTHROPIC_SMALL_FAST_MODEL="${ANTHROPIC_SMALL_FAST_MODEL:-${CLAUDE_VLLM_FAST_MODEL:-$MODEL_ID}}"
export ANTHROPIC_DEFAULT_HAIKU_MODEL="${ANTHROPIC_DEFAULT_HAIKU_MODEL:-$ANTHROPIC_SMALL_FAST_MODEL}"
# Claude Code only knows the context window of models it ships a table for, and
# assumes 200k for anything else — so a 393k model would auto-compact at half
# its capacity. Tell it the real number when the provider config states one.
if [ -n "${FOUND_CONTEXT:-}" ] && [ -z "${CLAUDE_CODE_MAX_CONTEXT_TOKENS:-}" ]; then
  export CLAUDE_CODE_MAX_CONTEXT_TOKENS="$FOUND_CONTEXT"
fi
# Beta headers the gateway does not implement make it reject otherwise fine
# requests.
export CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS="${CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS:-1}"
# Stops Claude Code phoning home about a non-Anthropic endpoint.
export CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC="${CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC:-1}"

if [ "$PRINT_ENV" = 1 ]; then
  for v in ANTHROPIC_BASE_URL ANTHROPIC_MODEL ANTHROPIC_SMALL_FAST_MODEL \
           ANTHROPIC_DEFAULT_HAIKU_MODEL CLAUDE_CODE_MAX_CONTEXT_TOKENS \
           CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS \
           CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC; do
    [ -n "${!v:-}" ] || continue
    printf 'export %s=%q\n' "$v" "${!v}"
  done
  # Never printed: the credential. Use --list to confirm one was found.
  echo 'export ANTHROPIC_AUTH_TOKEN=<redacted>'
  echo 'unset ANTHROPIC_API_KEY'
  exit 0
fi

command -v claude >/dev/null || { echo "claude-vllm: claude is not on PATH" >&2; exit 1; }
echo "claude-vllm: ${FOUND_PROVIDER:-custom} · ${ANTHROPIC_MODEL:-<gateway default>} · $ANTHROPIC_BASE_URL" >&2
exec claude "${CLAUDE_ARGS[@]}"