#!/usr/bin/env bash
set -euo pipefail

usage() {
  cat <<EOF
Usage: validate.sh <skill-dir>

Validate a skill directory against the agentskills.io specification.

Arguments:
  skill-dir  Path to the skill directory containing SKILL.md.

Exit codes:
  0  All checks passed
  1  One or more checks failed
EOF
}

if [[ "${1:-}" == "--help" || "${1:-}" == "-h" ]]; then
  usage
  exit 0
fi

if [[ $# -lt 1 ]]; then
  echo "Error: skill-dir is required." >&2
  echo "" >&2
  usage >&2
  exit 1
fi

python3 -u - "$1" <<'PYTHON'
import sys
import os
import re

skill_dir = os.path.abspath(sys.argv[1])
skill_md = os.path.join(skill_dir, "SKILL.md")

if not os.path.isfile(skill_md):
    print(f"Error: '{skill_md}' not found.", file=sys.stderr)
    sys.exit(1)

with open(skill_md) as f:
    content = f.read()

failed = False

def ok(msg):
    print(f"PASS  {msg}")

def fail(msg):
    global failed
    print(f"FAIL  {msg}")
    failed = True

# --- Parse frontmatter ---
fm_match = re.match(r'^---\n(.*?)\n---', content, re.DOTALL)
if not fm_match:
    fail("No valid YAML frontmatter block found (expected ---...---)")
    sys.exit(1)

fm = fm_match.group(1)
body_start = fm_match.end()

# Extract name
name_m = re.search(r'^name:\s*(\S+)', fm, re.MULTILINE)
name = name_m.group(1).strip('"\'') if name_m else ""

# Extract description — inline or block scalar (> or |)
desc = ""
desc_m = re.search(r'^description:\s*([>|])\n((?:[ \t]+.+\n?)+)', fm, re.MULTILINE)
if desc_m:
    raw = desc_m.group(2)
    desc = re.sub(r'\s+', ' ', raw).strip()
else:
    desc_inline = re.search(r'^description:\s*(.+)', fm, re.MULTILINE)
    if desc_inline:
        desc = desc_inline.group(1).strip()

dir_name = os.path.basename(skill_dir)

# --- Checks ---

# name present
if name:
    ok(f"name present: '{name}'")
else:
    fail("name field is missing or empty")

# name matches directory
if name and dir_name:
    if name == dir_name:
        ok(f"name '{name}' matches directory '{dir_name}'")
    else:
        fail(f"name '{name}' does not match directory '{dir_name}'")

# name length
if name:
    if len(name) <= 64:
        ok(f"name length {len(name)} chars (limit: 64)")
    else:
        fail(f"name '{name}' is {len(name)} chars — exceeds 64-character limit")

# name format
if name:
    if re.match(r'^[a-z0-9]+(-[a-z0-9]+)*$', name):
        ok(f"name format valid (kebab-case)")
    else:
        fail(f"name '{name}' is invalid — use lowercase letters, numbers, and hyphens only; no leading, trailing, or consecutive hyphens")

# description present
if desc:
    ok(f"description present")
else:
    fail("description field is missing or empty")

# description length
if desc:
    dlen = len(desc)
    if dlen <= 1024:
        ok(f"description length {dlen} chars (limit: 1024)")
    else:
        fail(f"description length {dlen} chars — exceeds 1024-character limit")

# Unfilled placeholder detection — matches FILL IN: followed by actual content,
# but not backtick-quoted references like `FILL IN:` used in instructions.
PLACEHOLDER_RE = re.compile(r'(?<!`)FILL IN:[^`\n]')

# description contains unfilled placeholder
if desc and PLACEHOLDER_RE.search(desc):
    fail("description still contains 'FILL IN:' placeholder — replace before shipping")
else:
    if desc:
        ok("description has no unfilled placeholders")

# SKILL.md size ceilings (agentskills.io skill-authoring.md: 500 lines,
# ~5,000 tokens). Both constants are DUPLICATED from the repo-root pre-commit
# hook scripts/skill-size-check.sh — a plugin skill's scripts cannot read files
# outside the plugin directory once the plugin is cache-installed, so there is
# no single source to share. Keep the two in sync by hand: if they drift, this
# audit will report a skill ready to ship that the commit hook then rejects.
MAX_LINES = 500
MAX_WORDS = 2900  # word-count proxy for the ~5,000-token ceiling

line_count = len(content.splitlines())
if line_count <= MAX_LINES:
    ok(f"SKILL.md line count {line_count} (limit: {MAX_LINES})")
else:
    fail(f"SKILL.md line count {line_count} — exceeds {MAX_LINES}-line limit")

# str.split() with no argument splits on runs of whitespace, matching the
# `wc -w` the hook uses, and counts the whole file including frontmatter.
word_count = len(content.split())
if word_count <= MAX_WORDS:
    ok(f"SKILL.md word count {word_count} (limit: {MAX_WORDS}, proxy for ~5,000 tokens)")
else:
    fail(f"SKILL.md word count {word_count} — exceeds {MAX_WORDS}-word limit (proxy for ~5,000 tokens)")

# Body unfilled placeholders
body = content[body_start:]
fill_matches = PLACEHOLDER_RE.findall(body)
if fill_matches:
    fail(f"SKILL.md body contains {len(fill_matches)} unfilled 'FILL IN:' placeholder(s)")
else:
    ok("SKILL.md body has no unfilled placeholders")

# Scripts checks
scripts_dir = os.path.join(skill_dir, "scripts")
if os.path.isdir(scripts_dir):
    scripts = [f for f in os.listdir(scripts_dir)
               if os.path.isfile(os.path.join(scripts_dir, f)) and not f.endswith('.md')]
    for fname in scripts:
        fpath = os.path.join(scripts_dir, fname)
        with open(fpath) as f:
            sc = f.read()
        # Interactive prompt heuristic
        if re.search(r'^\s*(read\s|input\()', sc, re.MULTILINE):
            fail(f"scripts/{fname}: may use interactive input (read/input detected)")
        else:
            ok(f"scripts/{fname}: no interactive prompts detected")
        # Executable bit
        if os.access(fpath, os.X_OK):
            ok(f"scripts/{fname}: is executable")
        else:
            fail(f"scripts/{fname}: not executable — run: chmod +x {fpath}")

# Summary
print()
if not failed:
    print("All checks passed.")
    sys.exit(0)
else:
    print("One or more checks failed.")
    sys.exit(1)
PYTHON