From 6d9895a15275beddb05d02a74e016df9f517cd10 Mon Sep 17 00:00:00 2001
From: Valentin Brandl <vbrandl@riseup.net>
Date: Tue, 23 Oct 2018 15:07:50 +0200
Subject: [PATCH] Update intro-crypto u1

---
 school/intro-crypto/uebung/01/01.tex          |  2 +-
 school/intro-crypto/uebung/01/u01/src/main.rs | 86 ++++++++++++++++---
 2 files changed, 73 insertions(+), 15 deletions(-)

diff --git a/school/intro-crypto/uebung/01/01.tex b/school/intro-crypto/uebung/01/01.tex
index f88e5ce..a061e40 100644
--- a/school/intro-crypto/uebung/01/01.tex
+++ b/school/intro-crypto/uebung/01/01.tex
@@ -21,7 +21,7 @@
 \def \matrikel {108018274494}				%
 % \def \pname {Vorname2 Nachname2}				%
 % \def \pmatrikel {Matrikelnummer2}				%
-\def \gruppe {Gruppenkuerzel}					%
+\def \gruppe {Gruppe 193}					%
 \def \uebung {1}								%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
diff --git a/school/intro-crypto/uebung/01/u01/src/main.rs b/school/intro-crypto/uebung/01/u01/src/main.rs
index 93d3a5e..80e61df 100644
--- a/school/intro-crypto/uebung/01/u01/src/main.rs
+++ b/school/intro-crypto/uebung/01/u01/src/main.rs
@@ -4,10 +4,61 @@ use countmap::CountMap;
 use std::{
     collections::HashMap,
     fs::File,
-    io::{BufRead, BufReader},
+    io::{self, BufRead, BufReader},
     path::Path,
 };
 
+fn analyze_text<P: AsRef<Path>>(p: P) -> io::Result<CountMap<char, u32>> {
+    let mut map = CountMap::new();
+    let read = BufReader::new(File::open(p)?);
+    read.lines()
+        .filter(Result::is_ok)
+        .map(Result::unwrap)
+        .for_each(|l| {
+            l.chars().filter(|c| c.is_alphabetic()).for_each(|c| {
+                map.insert_or_increment(dumb_to_lowercase(c));
+            });
+        });
+    Ok(map)
+}
+
+fn create_mapping_table<I1, I2>(natural: I1, target: I2) -> HashMap<char, char>
+where
+    I1: IntoIterator<Item = (char, u32)>,
+    I2: IntoIterator<Item = (char, u32)>,
+{
+    let mut natural: Vec<_> = natural.into_iter().collect();
+    natural.sort_by(|(_, u1), (_, u2)| u2.cmp(u1));
+    let mut target: Vec<_> = target.into_iter().collect();
+    target.sort_by(|(_, u1), (_, u2)| u2.cmp(u1));
+    natural
+        .into_iter()
+        .zip(target.into_iter())
+        .map(|((c1, _), (c2, _))| (c1, c2))
+        .collect()
+}
+
+fn auto_decrypt<P1, P2>(natural: P1, target: P2) -> io::Result<String>
+where
+    P1: AsRef<Path>,
+    P2: AsRef<Path>,
+{
+    let natural_map = analyze_text(natural)?;
+    let target_map = analyze_text(&target)?;
+    let mapping = create_mapping_table(natural_map, target_map);
+    let read = BufReader::new(File::open(target)?);
+    let res: Vec<_> = read
+        .lines()
+        .filter(Result::is_ok)
+        .map(Result::unwrap)
+        .map(|l| {
+            l.chars()
+                .map(|c| mapping.get(&dumb_to_lowercase(c)).cloned().unwrap_or(c))
+                .collect::<String>()
+        }).collect();
+    Ok(res.as_slice().join("\n").to_owned())
+}
+
 fn count() {
     let args: Vec<_> = std::env::args().collect();
     let file = &args[1];
@@ -38,6 +89,10 @@ fn count() {
     println!("sum &\\text{{:}}& {}", sum);
 }
 
+fn dumb_to_lowercase(c: char) -> char {
+    c.to_lowercase().to_string().chars().nth(0).unwrap_or(c)
+}
+
 fn create_map<P: AsRef<Path>>(path: P) -> std::io::Result<HashMap<char, char>> {
     let read = BufReader::new(File::open(path)?);
     let mut map = HashMap::new();
@@ -55,18 +110,21 @@ fn create_map<P: AsRef<Path>>(path: P) -> std::io::Result<HashMap<char, char>> {
 }
 
 fn main() {
-    count();
     let args: Vec<_> = std::env::args().collect();
-    let target = &args[1];
-    let map = create_map(&args[2]).unwrap();
-    let read = BufReader::new(File::open(target).unwrap());
-    for line in read.lines() {
-        if let Ok(line) = line {
-            let s: String = line
-                .chars()
-                .map(|c| map.get(&c).cloned().unwrap_or(c))
-                .collect();
-            println!("{}", s);
-        }
-    }
+    let res = auto_decrypt(&args[1], &args[2]).unwrap();
+    println!("{}", res);
+    // count();
+    // let args: Vec<_> = std::env::args().collect();
+    // let target = &args[1];
+    // let map = create_map(&args[2]).unwrap();
+    // let read = BufReader::new(File::open(target).unwrap());
+    // for line in read.lines() {
+    //     if let Ok(line) = line {
+    //         let s: String = line
+    //             .chars()
+    //             .map(|c| map.get(&c).cloned().unwrap_or(c))
+    //             .collect();
+    //         println!("{}", s);
+    //     }
+    // }
 }