package main

import (
	"flag"
	"fmt"
	"os"
	"strings"

	"latprobe/internal/probe"
)

const usageText = `latprobe — measure per-phase HTTP request latency

Usage:
  latprobe [flags] <url> [url ...]

Flags:
  -n, --count int   Number of requests per URL (default 1)
      --json        Output results as JSON instead of text
  -h, --help        Show this help

Examples:
  latprobe https://example.com
  latprobe -n 5 https://example.com https://www.google.com
  latprobe --json https://example.com | jq .
`

func main() {
	count := flag.Int("count", 1, "number of requests per URL")
	flag.IntVar(count, "n", 1, "number of requests per URL (shorthand)")
	jsonOut := flag.Bool("json", false, "output results as JSON")

	flag.Usage = func() { fmt.Fprint(os.Stderr, usageText) }
	flag.Parse()

	urls := flag.Args()
	if len(urls) == 0 {
		fmt.Fprint(os.Stderr, usageText)
		os.Exit(1)
	}

	// --json and -n are parsed but not yet functional (wired in Steps 3–4).
	_ = jsonOut
	_ = count

	failed := false
	for i, url := range urls {
		if i > 0 {
			fmt.Println()
		}
		r := probe.Measure(url)
		if r.Err != nil {
			fmt.Fprintf(os.Stderr, "error %s: %v\n", r.URL, r.Err)
			failed = true
			continue
		}
		printResult(r)
	}

	if failed {
		os.Exit(1)
	}
}

func printResult(r probe.Result) {
	fmt.Printf("%s  (%d)\n", r.URL, r.StatusCode)

	phases := []struct {
		label string
		p     probe.Phase
	}{
		{"DNS lookup    ", r.DNS},
		{"TCP connect   ", r.Connect},
		{"TLS handshake ", r.TLS},
		{"Server (TTFB) ", r.TTFB},
		{"Transfer      ", r.Transfer},
	}

	for _, ph := range phases {
		if ph.p.Present {
			fmt.Printf("  %s :  %8.2f ms\n", ph.label, msec(ph.p))
		}
	}

	fmt.Println("  " + strings.Repeat("─", 29))
	fmt.Printf("  %s :  %8.2f ms\n", "Total         ", msec(r.Total))
}

func msec(p probe.Phase) float64 {
	return float64(p.Duration.Microseconds()) / 1000
}