From 5ce1094931cf0f1464523c80a2bc89ac7798ec4b Mon Sep 17 00:00:00 2001
From: Alexandre Bury <alexandre.bury@gmail.com>
Date: Wed, 27 Jul 2016 23:51:54 -0700
Subject: [PATCH] Better progress bar example

Shows multiple progress bars updated together.
---
 Cargo.toml           |   3 +
 examples/progress.rs | 135 +++++++++++++++++++++++++++++++++----------
 2 files changed, 107 insertions(+), 31 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index a390b0a..6412de8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,5 +16,8 @@ toml = "0.1"
 unicode-segmentation = "0.1.2"
 unicode-width = "0.1.3"
 
+[dev-dependencies]
+rand = "0.3"
+
 [lib]
 name = "cursive"
diff --git a/examples/progress.rs b/examples/progress.rs
index 7b4cdc2..efa4787 100644
--- a/examples/progress.rs
+++ b/examples/progress.rs
@@ -1,49 +1,122 @@
 extern crate cursive;
+extern crate rand;
+
+use rand::Rng;
 
 use cursive::prelude::*;
+use cursive::view::{Counter, Ticker};
 
 use std::thread;
+use std::cmp::min;
 use std::time::Duration;
 
 fn main() {
     let mut siv = Cursive::new();
 
+    // We'll start slowly with a simple start button...
     siv.add_layer(Dialog::empty()
         .title("Progress bar example")
         .padding((0, 0, 1, 1))
-        .content(Button::new("Start", |s| {
-            // Number of ticks
-            let n_max = 1000;
-
-            // This is the callback channel
-            let cb = s.cb_sink().clone();
-
-            s.pop_layer();
-            s.add_layer(Panel::new(FullView::full_width(
-                ProgressBar::new()
-                    .range(0, n_max)
-                    .with_task(move |ticker| {
-                        // This closure will be called in a separate thread.
-                        for _ in 0..n_max {
-                            thread::sleep(Duration::from_millis(5));
-                            // The ticker method increases the progress value
-                            ticker(1);
-                        }
-
-                        // When we're done, send a callback through the channel
-                        cb.send(Box::new(move |s| {
-                            s.pop_layer();
-                            s.add_layer(Dialog::empty()
-                                        .title("Work done!")
-                                        .content(TextView::new("Phew!"))
-                                        .button("Finally!", |s| s.quit()));
-                        }))
-                        .unwrap();
-                    })
-            )));
-        })));
+        .content(Button::new("Start", phase_1)));
 
+    // Auto-refresh is currently required for animated views
     siv.set_fps(30);
 
     siv.run();
 }
+
+// Function to simulate a long process.
+fn fake_load(n_max: usize, ticker: Ticker) {
+    for _ in 0..n_max {
+        thread::sleep(Duration::from_millis(5));
+        // The ticker method increases the progress value
+        ticker(1);
+    }
+}
+
+fn phase_1(s: &mut Cursive) {
+    // Phase 1 is easy: a simple pre-loading.
+
+    // Number of ticks
+    let n_max = 500;
+
+    // This is the callback channel
+    let cb = s.cb_sink().clone();
+
+    s.pop_layer();
+    s.add_layer(Panel::new(FullView::full_width(ProgressBar::new()
+        .range(0, n_max)
+        .with_task(move |ticker| {
+            // This closure will be called in a separate thread.
+            fake_load(n_max, ticker);
+
+            // When we're done, send a callback through the channel
+            cb.send(Box::new(coffee_break)).unwrap();
+        }))));
+}
+
+fn coffee_break(s: &mut Cursive) {
+    // A little break before things get serious.
+    s.pop_layer();
+    s.add_layer(Dialog::empty()
+        .title("Preparation complete")
+        .content(TextView::new("Now, the real deal!"))
+        .button("Again??", phase_2));
+}
+
+fn phase_2(s: &mut Cursive) {
+    // Now, we'll run N tasks
+    // (It could be downloading a file, extracting an archive,
+    // reticulating sprites, ...)
+    let n_bars = 10;
+    // Each task will have its own shiny counter
+    let counters: Vec<_> = (0..n_bars).map(|_| Counter::new(0)).collect();
+    // To make things more interesting, we'll give a random speed to each bar
+    let speeds: Vec<_> =
+        (0..n_bars).map(|_| rand::thread_rng().gen_range(50, 150)).collect();
+
+    let n_max = 100000;
+    let cb = s.cb_sink().clone();
+
+    // Let's prepare the progress bars...
+    let mut linear = LinearLayout::vertical();
+    for c in &counters {
+        linear.add_child(ProgressBar::new()
+            .max(n_max)
+            .with_value(c.clone()));
+    }
+
+    s.pop_layer();
+    s.add_layer(Dialog::new(FullView::full_width(linear))
+        .title("Just a moment..."));
+
+    // And we start the worker thread.
+    thread::spawn(move || {
+        loop {
+            thread::sleep(Duration::from_millis(5));
+            let mut done = true;
+            for (c, s) in counters.iter().zip(&speeds) {
+                let ticks = min(n_max - c.get(), *s);
+                c.tick(ticks);
+                if c.get() < n_max {
+                    done = false;
+                }
+            }
+            if done {
+                break;
+            }
+        }
+
+        cb.send(Box::new(final_step)).unwrap();
+    });
+}
+
+fn final_step(s: &mut Cursive) {
+    // A little break before things get serious.
+    s.pop_layer();
+    s.add_layer(Dialog::empty()
+        .title("Report")
+        .content(TextView::new("Time travel was a success!\n\
+                               We went forward a few seconds!!"))
+        .button("That's it?", |s| s.quit()));
+}