//
// section-parse.go: scan standard input and do the following:
//
// 1. look for a section that begins with "test-text "STUFF/foo" and ends
//    with a blank line.
// 2. print the "bar.DIGITS" suffix for each line in the section
//
// Build:
//
//   go build section-parse.go
//
// Alternatively, you can run this script directly like this:
//
//   go run ./section-parse.go < input.txt
//
// Example:
//
//   > go run ./section-parse.go < input.txt
//   bar.1
//   bar.2
//   bar.3
//   bar.4
//
package main

import (
  "fmt"
  "io"
  "log"
  "os"
  "regexp"
  "strings"
)

// section header regex
var headerRe = regexp.MustCompile(`^test-text ".*/foo"$`)

// section footer regex
var footerRe = regexp.MustCompile(`^\s*$`)

// body line regex
var bodyRe = regexp.MustCompile(`^.*(bar\.\d+)$`)

// Is the given line a section header?
func isHeader(s string) bool {
  return headerRe.MatchString(s)
}

// Is the given line a section footer?
func isFooter(s string) bool {
  return footerRe.MatchString(s)
}

// Read slice of lines from standard input.
func getLines() []string {
  // read from standard input
  buf, err := io.ReadAll(os.Stdin)
  if err != nil {
    log.Fatal(err)
  }

  // split into lines, return result
  return strings.Split(string(buf), "\n")
}

func main() {
  inBody := false

  // walk lines
  for _, line := range(getLines()) {
    if (!inBody && isHeader(line)) || (inBody && isFooter(line)) {
      // toggle state
      inBody = !inBody
    } else if inBody {
      // match digits, check for error
      md := bodyRe.FindStringSubmatch(line)
      if len(md) < 2 {
        log.Fatalf("invalid body line: %s", line)
      }

      // print match to standard output
      fmt.Println(md[1])
    }
  }
}