package main

import (
	"fmt"
	"io"
	"strings"
	"text/tabwriter"
	"time"
)

// printTable writes a formatted table with tabwriter. The first row is treated
// as the header and separated from data rows by a rule of dashes.
func printTable(w io.Writer, rows [][]string) {
	if len(rows) == 0 {
		return
	}
	tw := tabwriter.NewWriter(w, 0, 0, 2, ' ', 0)
	for i, row := range rows {
		fmt.Fprintln(tw, strings.Join(row, "\t"))
		if i == 0 {
			// Print a divider matching the header width.
			dashes := make([]string, len(row))
			for j, h := range row {
				dashes[j] = strings.Repeat("-", len(h))
			}
			fmt.Fprintln(tw, strings.Join(dashes, "\t"))
		}
	}
	tw.Flush()
}

// fmtCount formats a count with a space as the thousands separator.
// e.g. 1234567 → "1 234 567"
func fmtCount(n int64) string {
	s := fmt.Sprintf("%d", n)
	if len(s) <= 3 {
		return s
	}
	var b strings.Builder
	start := len(s) % 3
	if start > 0 {
		b.WriteString(s[:start])
	}
	for i := start; i < len(s); i += 3 {
		if i > 0 {
			b.WriteByte(' ')
		}
		b.WriteString(s[i : i+3])
	}
	return b.String()
}

// fmtTime formats a unix timestamp as "2006-01-02 15:04" UTC.
func fmtTime(unix int64) string {
	return time.Unix(unix, 0).UTC().Format("2006-01-02 15:04")
}

// targetHeader returns the header line to print before each target's results.
// Returns empty string when there is only one target (clean single-target output).
func targetHeader(target, source string, nTargets int) string {
	if nTargets <= 1 {
		return ""
	}
	if source != "" && source != target {
		return fmt.Sprintf("=== %s (%s) ===", source, target)
	}
	return fmt.Sprintf("=== %s ===", target)
}