From 804bc1c12a79e1d54916816d991d4209c63419c4 Mon Sep 17 00:00:00 2001
From: Stefan Majewsky <majewsky@gmx.net>
Date: Sun, 17 Apr 2022 01:57:02 +0200
Subject: [PATCH] scan inputs

---
 main.go |  21 +++++++++
 scan.go | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 154 insertions(+)
 create mode 100644 scan.go

diff --git a/main.go b/main.go
index 86aaafb..75c8b40 100644
--- a/main.go
+++ b/main.go
@@ -6,5 +6,26 @@
 
 package main
 
+import (
+	"fmt"
+	"os"
+)
+
 func main() {
+	scanResult := Scan()
+	fmt.Printf("%#v", scanResult)
+}
+
+func must(err error) {
+	if err != nil {
+		fail(err.Error())
+	}
+}
+
+func fail(msg string, args ...interface{}) {
+	if len(args) > 0 {
+		msg = fmt.Sprintf(msg, args...)
+	}
+	fmt.Fprintln(os.Stderr, "ERROR: ", msg)
+	os.Exit(1)
 }
diff --git a/scan.go b/scan.go
new file mode 100644
index 0000000..40421ce
--- /dev/null
+++ b/scan.go
@@ -0,0 +1,133 @@
+/*******************************************************************************
+* Copyright 2022 Stefan Majewsky <majewsky@gmx.net>
+* SPDX-License-Identifier: GPL-3.0-only
+* Refer to the file "LICENSE" for details.
+*******************************************************************************/
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type ScanResult struct {
+	//episode date
+	Day   int
+	Month int
+	Year  int
+	//files discovered
+	AudioFormats []string
+	//parts extracted from the shownotes
+	Title       string
+	Description string
+	//parts extracted from the chaptermarks
+	ChapterMarks []ChapterMark
+}
+
+type ChapterMark struct {
+	StartTime string
+	Title     string
+	URL       string
+}
+
+func Scan() (result ScanResult) {
+	//determine episode date by finding shownotes file
+	names, err := filepath.Glob("shownotes-pentaradio-*.txt")
+	must(err)
+	if len(names) == 0 {
+		fail("no files found: shownotes-pentaradio-*.txt")
+	}
+	if len(names) > 1 {
+		fail("multiple files found: shownotes-pentaradio-*.txt")
+	}
+	match := regexp.MustCompile(`^shownotes-pentaradio-(\d{4})-(\d{2})-(\d{2})\.txt$`).FindStringSubmatch(names[0])
+	if match == nil {
+		fail("cannot extract date from file name: %s", names[0])
+	}
+
+	//validate episode date
+	result.Year, _ = strconv.Atoi(match[1])
+	if result.Year < 2000 || result.Year > 2999 {
+		fail("invalid year in filename: %s", names[0])
+	}
+	result.Month, _ = strconv.Atoi(match[2])
+	if result.Month < 1 || result.Month > 12 {
+		fail("invalid month in filename: %s", names[0])
+	}
+	result.Day, _ = strconv.Atoi(match[3])
+	if result.Day < 1 || result.Day > 31 {
+		fail("invalid day in filename: %s", names[0])
+	}
+
+	//parse input files
+	result.ParseShownotes(names[0])
+	chapterMarksPath := fmt.Sprintf("chapter-pentaradio-%04d-%02d-%02d.dat", result.Year, result.Month, result.Day)
+	result.ParseChapterMarks(chapterMarksPath)
+
+	//collect audio files
+	pattern := fmt.Sprintf("pentaradio-%04d-%02d-%02d.*", result.Year, result.Month, result.Day)
+	names, err = filepath.Glob(pattern)
+	must(err)
+	if len(names) == 0 {
+		fail("no files found: %s", pattern)
+	}
+	for _, name := range names {
+		result.AudioFormats = append(result.AudioFormats, strings.TrimPrefix(filepath.Ext(name), "."))
+	}
+
+	//TODO: parse chapter marks
+
+	return
+}
+
+var monthWords = []string{
+	"Null",
+	"Januar", "Februar", "März", "April",
+	"Mai", "Juni", "Juli", "August",
+	"September", "Oktober", "November", "Dezember",
+}
+
+func (scan *ScanResult) ParseShownotes(path string) {
+	buf, err := os.ReadFile(path)
+	must(err)
+
+	expectedTitle := fmt.Sprintf("Pentaradio vom %d. %s %d", scan.Day, monthWords[scan.Month], scan.Year)
+	shownotesRx := regexp.MustCompile(
+		fmt.Sprintf(`^# %s\n`, expectedTitle) + //header line
+			`# Titel: "(.*)"\n\n` + //episode title
+			`((?s:.*?))\n\n##\s`, //short description (everything up until the first <h2>)
+	)
+	match := shownotesRx.FindStringSubmatch(string(buf))
+	if match == nil {
+		fail("shownotes do not match expected format: /%s/", shownotesRx.String())
+	}
+
+	scan.Title = match[1]
+	scan.Description = match[2]
+}
+
+func (scan *ScanResult) ParseChapterMarks(path string) {
+	buf, err := os.ReadFile(path)
+	must(err)
+
+	lineRx := regexp.MustCompile(`^(\d\d:\d\d:\d\d.\d\d\d) (\S.*?\S)(?: <(https?://.*)>)?$`)
+	for _, line := range strings.Split(string(buf), "\n") {
+		if strings.TrimSpace(line) == "" {
+			continue
+		}
+		match := lineRx.FindStringSubmatch(line)
+		if match == nil {
+			fail("invalid format for chapter mark: %s", line)
+		}
+		scan.ChapterMarks = append(scan.ChapterMarks, ChapterMark{
+			StartTime: match[1],
+			Title:     match[2],
+			URL:       match[3],
+		})
+	}
+}