#!/usr/bin/env bash
# Frisk Common - Utilities

# Atomic write: write content to tmp file, validate, then mv
# Usage: atomic_write <target_path> <content_from_stdin>
atomic_write() {
    local target="$1"
    local tmp
    tmp=$(mktemp "${target}.XXXXXX.new")
    cat > "$tmp"
    if [[ -s "$tmp" ]]; then
        mv -f "$tmp" "$target"
        return 0
    else
        rm -f "$tmp"
        echo "atomic_write: refused to write empty file to $target" >&2
        return 1
    fi
}

# Validate JSON file
validate_json() {
    local f="$1"
    if jq empty "$f" 2>/dev/null; then
        return 0
    else
        echo "validate_json: $f is not valid JSON" >&2
        return 1
    fi
}

# Safe download: fetch URL, validate, atomic write
# Usage: safe_download <url> <target_path> [validate_cmd]
safe_download() {
    local url="$1"
    local target="$2"
    local validate_cmd="${3:-}"
    local tmp
    tmp=$(mktemp "${target}.XXXXXX.new")

    if ! curl -fsSL --max-time 120 --retry 3 --retry-delay 5 "$url" -o "$tmp"; then
        rm -f "$tmp"
        echo "safe_download: FAILED to fetch $url" >&2
        return 1
    fi

    if [[ -n "$validate_cmd" ]]; then
        case "$validate_cmd" in
            jq\ *)
                # Invoke jq validation directly
                if ! $validate_cmd "$tmp"; then
                    rm -f "$tmp"
                    echo "safe_download: validation failed for $url" >&2
                    return 1
                fi
                ;;
            *)
                # Unknown validation command — warn and skip
                echo "safe_download: unknown validation command '$validate_cmd', skipping validation" >&2
                ;;
        esac
    fi

    mv -f "$tmp" "$target"
    return 0
}

# Get script directory
script_dir() {
    local src="${BASH_SOURCE[0]}"
    while [[ -L "$src" ]]; do
        local dir
        dir="$(cd -P "$(dirname "$src")" && pwd)"
        src="$(readlink "$src")"
        [[ "$src" != /* ]] && src="$dir/$src"
    done
    cd -P "$(dirname "$src")" && pwd
}
# Validate CSV: check first line starts with alpha header (not HTML error)
# Usage: validate_csv <file> [header_pattern]
# Returns 0 if valid, 1 if invalid (e.g., HTML error page, empty file)
validate_csv() {
    local file="$1"
    local header_pattern="${2:-^[a-zA-Z]}"
    if ! head -1 "$file" | grep -qE "$header_pattern"; then
        return 1
    fi
    return 0
}