#!/usr/bin/env bash
# setup-pi.sh — Install pi and configure models/settings like the reference machine.
#
# Usage:
#   curl -fsSL <url> | bash          # or
#   bash setup-pi.sh
#   bash setup-pi.sh --force         # overwrite existing config files
#   PI_INSTALL_METHOD=npm bash setup-pi.sh
#
# After install, edit API keys in:
#   ~/.pi/agent/models.json

set -euo pipefail

PI_HOME="${PI_HOME:-$HOME/.pi}"
AGENT_DIR="$PI_HOME/agent"
FORCE=0
INSTALL_METHOD="${PI_INSTALL_METHOD:-auto}" # auto | bun | npm
PI_PACKAGE="@earendil-works/pi-coding-agent"

# ── args ──────────────────────────────────────────────────────────────────────
for arg in "$@"; do
  case "$arg" in
    --force|-f) FORCE=1 ;;
    --bun)      INSTALL_METHOD=bun ;;
    --npm)      INSTALL_METHOD=npm ;;
    --help|-h)
      sed -n '2,14p' "$0"
      exit 0
      ;;
    *)
      echo "Unknown option: $arg" >&2
      exit 1
      ;;
  esac
done

# ── helpers ────────────────────────────────────────────────────────────────────
info()  { printf '\033[1;34m==>\033[0m %s\n' "$*"; }
ok()    { printf '\033[1;32m✓\033[0m  %s\n' "$*"; }
warn()  { printf '\033[1;33m!\033[0m  %s\n' "$*"; }
die()   { printf '\033[1;31m✗\033[0m  %s\n' "$*" >&2; exit 1; }

write_file() {
  # write_file <path> <heredoc via stdin>
  local path="$1"
  if [[ -f "$path" && $FORCE -eq 0 ]]; then
    warn "skip existing: $path  (use --force to overwrite)"
    return 0
  fi
  mkdir -p "$(dirname "$path")"
  cat > "$path"
  ok "wrote $path"
}

have() { command -v "$1" >/dev/null 2>&1; }

# ── 1. prerequisites ──────────────────────────────────────────────────────────
info "Checking prerequisites"

if ! have curl && ! have wget; then
  die "Need curl or wget"
fi

# Node is required for pi runtime even when installed via bun
if ! have node; then
  die "Node.js is required. Install Node 20+ then re-run."
fi

NODE_MAJOR="$(node -p 'process.versions.node.split(".")[0]')"
if (( NODE_MAJOR < 20 )); then
  warn "Node $NODE_MAJOR detected; pi recommends Node 20+"
fi
ok "node $(node -v)"

# ── 2. install pi ─────────────────────────────────────────────────────────────
info "Installing $PI_PACKAGE"

resolve_method() {
  case "$INSTALL_METHOD" in
    bun|npm) echo "$INSTALL_METHOD" ;;
    auto)
      if have bun; then echo bun
      elif have npm; then echo npm
      else die "Need bun or npm to install pi"
      fi
      ;;
    *) die "Invalid PI_INSTALL_METHOD=$INSTALL_METHOD (use auto|bun|npm)" ;;
  esac
}

METHOD="$(resolve_method)"
case "$METHOD" in
  bun)
    ok "using bun $(bun -v 2>/dev/null || true)"
    bun install -g "$PI_PACKAGE"
    # Ensure bun bin is on PATH for this session
    export BUN_INSTALL="${BUN_INSTALL:-$HOME/.bun}"
    export PATH="$BUN_INSTALL/bin:$PATH"
    ;;
  npm)
    ok "using npm $(npm -v 2>/dev/null || true)"
    npm install -g --ignore-scripts "$PI_PACKAGE"
    ;;
esac

if ! have pi; then
  die "pi binary not found on PATH after install. Add bun/npm global bin to PATH and re-run."
fi
ok "pi $(pi --version 2>/dev/null || echo installed) via $METHOD"

# ── 3. directory layout ───────────────────────────────────────────────────────
info "Creating $AGENT_DIR"
mkdir -p "$AGENT_DIR"/{sessions,extensions,skills,bin,npm,ayu/checkpoints}
ok "dirs ready"

# ── 4. settings.json ──────────────────────────────────────────────────────────
info "Writing settings.json"
write_file "$AGENT_DIR/settings.json" <<'EOF'
{
  "defaultProvider": "llm-gw",
  "defaultModel": "code",
  "packages": [],
  "images": {
    "blockImages": true
  },
  "terminal": {
    "showTerminalProgress": true
  },
  "steeringMode": "one-at-a-time",
  "theme": "dark",
  "hideThinkingBlock": true,
  "collapseChangelog": true,
  "defaultProjectTrust": "always",
  "warnings": {
    "anthropicExtraUsage": true
  },
  "defaultThinkingLevel": "high",
  "enableInstallTelemetry": false,
  "compaction": {
    "enabled": true,
    "reserveTokens": 25600,
    "keepRecentTokens": 20000
  },
  "retry": {
    "enabled": true,
    "maxRetries": 3,
    "baseDelayMs": 2000,
    "provider": {
      "timeoutMs": 300000,
      "maxRetries": 2,
      "maxRetryDelayMs": 60000
    }
  },
  "lsp": {
    "hookMode": "disabled"
  },
  "httpIdleTimeoutMs": 120000,
  "treeFilterMode": "default"
}
EOF

# ── 5. models.json (template keys) ────────────────────────────────────────────
info "Writing models.json (API key placeholders)"
write_file "$AGENT_DIR/models.json" <<'EOF'
{
  "providers": {
    "llm-gw": {
      "baseUrl": "https://llm-gw.luulam.dev/v1",
      "apiKey": "YOUR_LLM_GW_API_KEY",
      "api": "openai-completions",
      "models": [
        {
          "id": "code",
          "name": "code",
          "reasoning": false,
          "input": ["text"],
          "contextWindow": 256000,
          "maxTokens": 128000,
          "cost": { "input": 0, "output": 0, "cacheRead": 0, "cacheWrite": 0 }
        }
      ]
    },
    "mbbank": {
      "baseUrl": "https://api-sandbox.mbbank.com.vn/llm-gateway-dev/v1",
      "apiKey": "YOUR_MBBANK_API_KEY",
      "api": "openai-completions",
      "models": [
        {
          "id": "glm-text",
          "name": "glm-text",
          "reasoning": false,
          "input": ["text"],
          "contextWindow": 256000,
          "maxTokens": 128000,
          "cost": { "input": 0, "output": 0, "cacheRead": 0, "cacheWrite": 0 }
        }
      ]
    }
  }
}
EOF

# ── 6. APPEND_SYSTEM.md ───────────────────────────────────────────────────────
info "Writing APPEND_SYSTEM.md"
write_file "$AGENT_DIR/APPEND_SYSTEM.md" <<'EOF'
# Default Coding Guidelines

Apply these guidelines by default for all coding, reviewing, debugging, and refactoring tasks.

## Karpathy Guidelines

Behavioral guidelines to reduce common LLM coding mistakes. These guidelines bias toward caution over speed. For trivial tasks, use judgment.

### 1. Think Before Coding

Don't assume. Don't hide confusion. Surface tradeoffs.

Before implementing:
- State your assumptions explicitly. If uncertain, ask.
- If multiple interpretations exist, present them; don't pick silently.
- If a simpler approach exists, say so. Push back when warranted.
- If something is unclear, stop. Name what's confusing. Ask.

### 2. Simplicity First

Minimum code that solves the problem. Nothing speculative.

- No features beyond what was asked.
- No abstractions for single-use code.
- No "flexibility" or "configurability" that wasn't requested.
- No error handling for impossible scenarios.
- If you write 200 lines and it could be 50, rewrite it.

Ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify.

### 3. Surgical Changes

Touch only what you must. Clean up only your own mess.

When editing existing code:
- Don't "improve" adjacent code, comments, or formatting.
- Don't refactor things that aren't broken.
- Match existing style, even if you'd do it differently.
- If you notice unrelated dead code, mention it; don't delete it.

When your changes create orphans:
- Remove imports, variables, or functions that your changes made unused.
- Don't remove pre-existing dead code unless asked.

The test: every changed line should trace directly to the user's request.

### 4. Goal-Driven Execution

Define success criteria. Loop until verified.

Transform tasks into verifiable goals:
- "Add validation" → "Write tests for invalid inputs, then make them pass."
- "Fix the bug" → "Write a test that reproduces it, then make it pass."
- "Refactor X" → "Ensure tests pass before and after."

For multi-step tasks, state a brief plan:

```text
1. [Step] → verify: [check]
2. [Step] → verify: [check]
3. [Step] → verify: [check]
```

Strong success criteria let you loop independently. Weak criteria like "make it work" require clarification.
EOF

# ── 7. minimal auth + trust stubs ─────────────────────────────────────────────
# auth.json empty object is fine; keys live in models.json for custom providers
if [[ ! -f "$AGENT_DIR/auth.json" || $FORCE -eq 1 ]]; then
  echo '{}' > "$AGENT_DIR/auth.json"
  ok "wrote $AGENT_DIR/auth.json"
else
  warn "skip existing: $AGENT_DIR/auth.json"
fi

if [[ ! -f "$AGENT_DIR/trust.json" || $FORCE -eq 1 ]]; then
  # Trust the pi home dir by default; add project paths later via pi UI
  cat > "$AGENT_DIR/trust.json" <<EOF
{
  "$PI_HOME": true
}
EOF
  ok "wrote $AGENT_DIR/trust.json"
else
  warn "skip existing: $AGENT_DIR/trust.json"
fi

# ── 8. PATH hint for bun installs ─────────────────────────────────────────────
ensure_path_hint() {
  if [[ "$METHOD" != "bun" ]]; then
    return 0
  fi

  local rc=""
  if [[ -n "${ZSH_VERSION:-}" ]] || [[ -f "$HOME/.zshrc" && ! -f "$HOME/.bashrc" ]]; then
    rc="$HOME/.zshrc"
  elif [[ -f "$HOME/.bashrc" ]]; then
    rc="$HOME/.bashrc"
  elif [[ -f "$HOME/.profile" ]]; then
    rc="$HOME/.profile"
  fi

  local marker='# >>> pi / bun >>>'
  if [[ -z "$rc" ]]; then
    warn "Could not detect shell rc. Ensure \$HOME/.bun/bin is on PATH."
    return 0
  fi

  if grep -qF "$marker" "$rc" 2>/dev/null; then
    ok "PATH already configured in $rc"
    return 0
  fi

  # Append without command-substitution (avoids ')' inside case breaking $())
  {
    echo ""
    echo "# >>> pi / bun >>>"
    echo 'export BUN_INSTALL="${BUN_INSTALL:-$HOME/.bun}"'
    echo 'if [[ ":$PATH:" != *":$BUN_INSTALL/bin:"* ]]; then'
    echo '  export PATH="$BUN_INSTALL/bin:$PATH"'
    echo 'fi'
    echo "# <<< pi / bun <<<"
  } >> "$rc"
  ok "appended bun PATH to $rc"
}
ensure_path_hint

# ── done ──────────────────────────────────────────────────────────────────────
cat <<EOF

────────────────────────────────────────────────────────
  Pi core setup complete
────────────────────────────────────────────────────────
  Binary : $(command -v pi)
  Version: $(pi --version 2>/dev/null || echo unknown)
  Config : $AGENT_DIR

  Next steps:
    1. Edit API keys:
         $EDITOR "$AGENT_DIR/models.json"
       Replace:
         YOUR_LLM_GW_API_KEY
         YOUR_MBBANK_API_KEY

    2. Verify models:
         pi --list-models

    3. Start:
         pi
         # or pin model:
         pi --provider llm-gw --model code

  Re-run with --force to overwrite settings/models/APPEND_SYSTEM.
  Optional later:
    pi install npm:context-mode
    pi install npm:pi-mcp-adapter
    # ...other packages from the full machine profile
────────────────────────────────────────────────────────
EOF