#!/usr/bin/env bash
# Pre-commit hook: validate README.md YAML frontmatter for HuggingFace dataset card.
# Ensures required fields are present and non-empty.

set -euo pipefail

README="README.md"

if [ ! -f "$README" ]; then
    echo "Error: $README not found"
    exit 1
fi

# Extract YAML frontmatter (between opening and closing ---)
frontmatter=$(awk '/^---$/{n++; next} n==1{print} n==2{exit}' "$README")

if [ -z "$frontmatter" ]; then
    echo "Error: $README has no YAML frontmatter (must start with ---)"
    exit 1
fi

# Required fields per HuggingFace dataset card spec
required_fields=(
    "license"
    "task_categories"
    "size_categories"
)

errors=0
for field in "${required_fields[@]}"; do
    if ! echo "$frontmatter" | grep -q "^${field}:"; then
        echo "Error: $README missing required field '$field'"
        errors=$((errors + 1))
    else
        # Check the value isn't empty — either inline or as a YAML list on the next line
        inline_value=$(echo "$frontmatter" | grep "^${field}:" | sed "s/^${field}://" | sed 's/^[[:space:]]*//')
        if [ -z "$inline_value" ]; then
            # Value might be a multi-line list; check the next line starts with -
            if ! echo "$frontmatter" | grep -A1 "^${field}:" | tail -1 | grep -q '^- '; then
                echo "Error: $README field '$field' is empty"
                errors=$((errors + 1))
            fi
        fi
    fi
done

if [ "$errors" -gt 0 ]; then
    echo ""
    echo "See https://huggingface.co/docs/hub/datasets-cards#yaml-metadata"
    exit 1
fi