Implement a `changelog-generator` tool and example

3 files changed, 732 insertions, 0 deletions

diff --git a/examples/changelog/src/changelog.rs b/examples/changelog/src/changelog.rs
new file mode 100644
index 00000000..39cbb42c
--- /dev/null
+++ b/examples/changelog/src/changelog.rs
@@ -0,0 +1,354 @@
+use serde::Deserialize;
+use tokio::fs;
+use tokio::process;
+
+use std::env;
+use std::fmt;
+use std::io;
+use std::sync::Arc;
+
+#[derive(Debug, Clone)]
+pub struct Changelog {
+    ids: Vec<u64>,
+    added: Vec<String>,
+    changed: Vec<String>,
+    fixed: Vec<String>,
+    removed: Vec<String>,
+    authors: Vec<String>,
+}
+
+impl Changelog {
+    pub fn new() -> Self {
+        Self {
+            ids: Vec::new(),
+            added: Vec::new(),
+            changed: Vec::new(),
+            fixed: Vec::new(),
+            removed: Vec::new(),
+            authors: Vec::new(),
+        }
+    }
+
+    pub async fn list() -> Result<(Self, Vec<Candidate>), Error> {
+        let mut changelog = Self::new();
+
+        {
+            let markdown = fs::read_to_string("CHANGELOG.md").await?;
+
+            if let Some(unreleased) = markdown.split("\n## ").nth(1) {
+                let sections = unreleased.split("\n\n");
+
+                for section in sections {
+                    if section.starts_with("Many thanks to...") {
+                        for author in section.lines().skip(1) {
+                            let author = author.trim_start_matches("- @");
+
+                            if author.is_empty() {
+                                continue;
+                            }
+
+                            changelog.authors.push(author.to_owned());
+                        }
+
+                        continue;
+                    }
+
+                    let Some((_, rest)) = section.split_once("### ") else {
+                        continue;
+                    };
+
+                    let Some((name, rest)) = rest.split_once("\n") else {
+                        continue;
+                    };
+
+                    let category = match name {
+                        "Added" => Category::Added,
+                        "Fixed" => Category::Fixed,
+                        "Changed" => Category::Changed,
+                        "Removed" => Category::Removed,
+                        _ => continue,
+                    };
+
+                    for entry in rest.lines() {
+                        let Some((_, id)) = entry.split_once('#') else {
+                            continue;
+                        };
+
+                        let Some((id, _)) = id.split_once(']') else {
+                            continue;
+                        };
+
+                        let Ok(id): Result<u64, _> = id.parse() else {
+                            continue;
+                        };
+
+                        changelog.ids.push(id);
+
+                        let target = match category {
+                            Category::Added => &mut changelog.added,
+                            Category::Changed => &mut changelog.added,
+                            Category::Fixed => &mut changelog.fixed,
+                            Category::Removed => &mut changelog.removed,
+                        };
+
+                        target.push(entry.to_owned());
+                    }
+                }
+            }
+        }
+
+        let mut candidates = Candidate::list().await?;
+
+        for reviewed_entry in changelog.entries() {
+            candidates.retain(|candidate| candidate.id != reviewed_entry);
+        }
+
+        Ok((changelog, candidates))
+    }
+
+    pub fn len(&self) -> usize {
+        self.ids.len()
+    }
+
+    pub fn entries(&self) -> impl Iterator<Item = u64> + '_ {
+        self.ids.iter().copied()
+    }
+
+    pub fn push(&mut self, entry: Entry) {
+        self.ids.push(entry.id);
+
+        let item = format!(
+            "- {title}. [#{id}](https://github.com/iced-rs/iced/pull/{id})",
+            title = entry.title,
+            id = entry.id
+        );
+
+        let target = match entry.category {
+            Category::Added => &mut self.added,
+            Category::Changed => &mut self.added,
+            Category::Fixed => &mut self.fixed,
+            Category::Removed => &mut self.removed,
+        };
+
+        target.push(item);
+
+        if !self.authors.contains(&entry.author) {
+            self.authors.push(entry.author);
+            self.authors.sort_by_key(|author| author.to_lowercase());
+        }
+    }
+}
+
+impl fmt::Display for Changelog {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fn section(category: Category, entries: &[String]) -> String {
+            if entries.is_empty() {
+                return String::new();
+            }
+
+            format!("### {category}\n{list}\n", list = entries.join("\n"))
+        }
+
+        fn thank_you<'a>(authors: impl IntoIterator<Item = &'a str>) -> String {
+            let mut list = String::new();
+
+            for author in authors {
+                list.push_str(&format!("- @{author}\n"));
+            }
+
+            format!("Many thanks to...\n{list}")
+        }
+
+        let changelog = [
+            section(Category::Added, &self.added),
+            section(Category::Changed, &self.changed),
+            section(Category::Fixed, &self.fixed),
+            section(Category::Removed, &self.removed),
+            thank_you(self.authors.iter().map(String::as_str)),
+        ]
+        .into_iter()
+        .filter(|section| !section.is_empty())
+        .collect::<Vec<String>>()
+        .join("\n");
+
+        f.write_str(&changelog)
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Entry {
+    pub id: u64,
+    pub title: String,
+    pub category: Category,
+    pub author: String,
+}
+
+impl Entry {
+    pub fn new(
+        title: &str,
+        category: Category,
+        pull_request: &PullRequest,
+    ) -> Option<Self> {
+        let title = title.strip_suffix(".").unwrap_or(title);
+
+        if title.is_empty() {
+            return None;
+        };
+
+        Some(Self {
+            id: pull_request.id,
+            title: title.to_owned(),
+            category,
+            author: pull_request.author.clone(),
+        })
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Category {
+    Added,
+    Changed,
+    Fixed,
+    Removed,
+}
+
+impl Category {
+    pub const ALL: &'static [Self] =
+        &[Self::Added, Self::Changed, Self::Fixed, Self::Removed];
+
+    pub fn guess(label: &str) -> Option<Self> {
+        Some(match label {
+            "feature" | "addition" => Self::Added,
+            "change" => Self::Changed,
+            "bug" | "fix" => Self::Fixed,
+            _ => None?,
+        })
+    }
+}
+
+impl fmt::Display for Category {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(match self {
+            Category::Added => "Added",
+            Category::Changed => "Changed",
+            Category::Fixed => "Fixed",
+            Category::Removed => "Removed",
+        })
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Candidate {
+    pub id: u64,
+}
+
+#[derive(Debug, Clone)]
+pub struct PullRequest {
+    pub id: u64,
+    pub title: String,
+    pub description: String,
+    pub labels: Vec<String>,
+    pub author: String,
+}
+
+impl Candidate {
+    pub async fn list() -> Result<Vec<Candidate>, Error> {
+        let output = process::Command::new("git")
+            .args([
+                "log",
+                "--oneline",
+                "--grep",
+                "#[0-9]*",
+                "origin/latest..HEAD",
+            ])
+            .output()
+            .await?;
+
+        let log = String::from_utf8_lossy(&output.stdout);
+
+        Ok(log
+            .lines()
+            .filter(|title| !title.is_empty())
+            .filter_map(|title| {
+                let (_, pull_request) = title.split_once("#")?;
+                let (pull_request, _) = pull_request.split_once([')', ' '])?;
+
+                Some(Candidate {
+                    id: pull_request.parse().ok()?,
+                })
+            })
+            .collect())
+    }
+
+    pub async fn fetch(self) -> Result<PullRequest, Error> {
+        let request = reqwest::Client::new()
+            .request(
+                reqwest::Method::GET,
+                format!(
+                    "https://api.github.com/repos/iced-rs/iced/pulls/{}",
+                    self.id
+                ),
+            )
+            .header("User-Agent", "iced changelog generator")
+            .header(
+                "Authorization",
+                format!(
+                    "Bearer {}",
+                    env::var("GITHUB_TOKEN")
+                        .map_err(|_| Error::GitHubTokenNotFound)?
+                ),
+            );
+
+        #[derive(Deserialize)]
+        struct Schema {
+            title: String,
+            body: String,
+            user: User,
+            labels: Vec<Label>,
+        }
+
+        #[derive(Deserialize)]
+        struct User {
+            login: String,
+        }
+
+        #[derive(Deserialize)]
+        struct Label {
+            name: String,
+        }
+
+        let schema: Schema = request.send().await?.json().await?;
+
+        Ok(PullRequest {
+            id: self.id,
+            title: schema.title,
+            description: schema.body,
+            labels: schema.labels.into_iter().map(|label| label.name).collect(),
+            author: schema.user.login,
+        })
+    }
+}
+
+#[derive(Debug, Clone, thiserror::Error)]
+pub enum Error {
+    #[error("io operation failed: {0}")]
+    IOFailed(Arc<io::Error>),
+
+    #[error("http request failed: {0}")]
+    RequestFailed(Arc<reqwest::Error>),
+
+    #[error("no GITHUB_TOKEN variable was set")]
+    GitHubTokenNotFound,
+}
+
+impl From<io::Error> for Error {
+    fn from(error: io::Error) -> Self {
+        Error::IOFailed(Arc::new(error))
+    }
+}
+
+impl From<reqwest::Error> for Error {
+    fn from(error: reqwest::Error) -> Self {
+        Error::RequestFailed(Arc::new(error))
+    }
+}
diff --git a/examples/changelog/src/icon.rs b/examples/changelog/src/icon.rs
new file mode 100644
index 00000000..dd82e5b9
--- /dev/null
+++ b/examples/changelog/src/icon.rs
@@ -0,0 +1,10 @@
+use iced::widget::{text, Text};
+use iced::Font;
+
+pub const FONT_BYTES: &[u8] = include_bytes!("../fonts/changelog-icons.ttf");
+
+const FONT: Font = Font::with_name("changelog-icons");
+
+pub fn copy() -> Text<'static> {
+    text('\u{e800}').font(FONT)
+}
diff --git a/examples/changelog/src/main.rs b/examples/changelog/src/main.rs
new file mode 100644
index 00000000..73da0f2c
--- /dev/null
+++ b/examples/changelog/src/main.rs
@@ -0,0 +1,368 @@
+mod changelog;
+mod icon;
+
+use crate::changelog::Changelog;
+
+use iced::clipboard;
+use iced::font;
+use iced::widget::{
+    button, center, column, container, markdown, pick_list, progress_bar,
+    rich_text, row, scrollable, span, stack, text, text_input,
+};
+use iced::{Element, Fill, FillPortion, Font, Task, Theme};
+
+pub fn main() -> iced::Result {
+    iced::application("Changelog Generator", Generator::update, Generator::view)
+        .font(icon::FONT_BYTES)
+        .theme(Generator::theme)
+        .run_with(Generator::new)
+}
+
+enum Generator {
+    Loading,
+    Empty,
+    Reviewing {
+        changelog: Changelog,
+        pending: Vec<changelog::Candidate>,
+        state: State,
+        preview: Vec<markdown::Item>,
+    },
+}
+
+enum State {
+    Loading(changelog::Candidate),
+    Loaded {
+        pull_request: changelog::PullRequest,
+        description: Vec<markdown::Item>,
+        title: String,
+        category: changelog::Category,
+    },
+}
+
+#[derive(Debug, Clone)]
+enum Message {
+    ChangelogListed(
+        Result<(Changelog, Vec<changelog::Candidate>), changelog::Error>,
+    ),
+    PullRequestFetched(Result<changelog::PullRequest, changelog::Error>),
+    UrlClicked(markdown::Url),
+    TitleChanged(String),
+    CategorySelected(changelog::Category),
+    Next,
+    OpenPullRequest(u64),
+    CopyPreview,
+}
+
+impl Generator {
+    fn new() -> (Self, Task<Message>) {
+        (
+            Self::Loading,
+            Task::perform(Changelog::list(), Message::ChangelogListed),
+        )
+    }
+
+    fn update(&mut self, message: Message) -> Task<Message> {
+        match message {
+            Message::ChangelogListed(Ok((changelog, mut pending))) => {
+                if let Some(candidate) = pending.pop() {
+                    let preview =
+                        markdown::parse(&changelog.to_string()).collect();
+
+                    *self = Self::Reviewing {
+                        changelog,
+                        pending,
+                        state: State::Loading(candidate.clone()),
+                        preview,
+                    };
+
+                    Task::perform(
+                        candidate.fetch(),
+                        Message::PullRequestFetched,
+                    )
+                } else {
+                    *self = Self::Empty;
+
+                    Task::none()
+                }
+            }
+            Message::PullRequestFetched(Ok(pull_request)) => {
+                let Self::Reviewing { state, .. } = self else {
+                    return Task::none();
+                };
+
+                let description =
+                    markdown::parse(&pull_request.description).collect();
+
+                *state = State::Loaded {
+                    title: pull_request.title.clone(),
+                    category: pull_request
+                        .labels
+                        .iter()
+                        .map(String::as_str)
+                        .filter_map(changelog::Category::guess)
+                        .next()
+                        .unwrap_or(changelog::Category::Added),
+                    pull_request,
+                    description,
+                };
+
+                Task::none()
+            }
+            Message::ChangelogListed(Err(error))
+            | Message::PullRequestFetched(Err(error)) => {
+                log::error!("{error}");
+
+                Task::none()
+            }
+            Message::UrlClicked(url) => {
+                let _ = webbrowser::open(url.as_str());
+
+                Task::none()
+            }
+            Message::TitleChanged(new_title) => {
+                let Self::Reviewing { state, .. } = self else {
+                    return Task::none();
+                };
+
+                let State::Loaded { title, .. } = state else {
+                    return Task::none();
+                };
+
+                *title = new_title;
+
+                Task::none()
+            }
+            Message::CategorySelected(new_category) => {
+                let Self::Reviewing { state, .. } = self else {
+                    return Task::none();
+                };
+
+                let State::Loaded { category, .. } = state else {
+                    return Task::none();
+                };
+
+                *category = new_category;
+
+                Task::none()
+            }
+            Message::Next => {
+                let Self::Reviewing {
+                    changelog,
+                    pending,
+                    state,
+                    preview,
+                    ..
+                } = self
+                else {
+                    return Task::none();
+                };
+
+                let State::Loaded {
+                    title,
+                    category,
+                    pull_request,
+                    ..
+                } = state
+                else {
+                    return Task::none();
+                };
+
+                if let Some(entry) =
+                    changelog::Entry::new(title, *category, pull_request)
+                {
+                    changelog.push(entry);
+
+                    *preview =
+                        markdown::parse(&changelog.to_string()).collect();
+
+                    if let Some(candidate) = pending.pop() {
+                        *state = State::Loading(candidate.clone());
+
+                        Task::perform(
+                            candidate.fetch(),
+                            Message::PullRequestFetched,
+                        )
+                    } else {
+                        // TODO: We are done!
+                        Task::none()
+                    }
+                } else {
+                    Task::none()
+                }
+            }
+            Message::OpenPullRequest(id) => {
+                let _ = webbrowser::open(&format!(
+                    "https://github.com/iced-rs/iced/pull/{id}"
+                ));
+
+                Task::none()
+            }
+            Message::CopyPreview => {
+                let Self::Reviewing { changelog, .. } = self else {
+                    return Task::none();
+                };
+
+                clipboard::write(changelog.to_string())
+            }
+        }
+    }
+
+    fn view(&self) -> Element<Message> {
+        match self {
+            Self::Loading => center("Loading...").into(),
+            Self::Empty => center("No changes found!").into(),
+            Self::Reviewing {
+                changelog,
+                pending,
+                state,
+                preview,
+            } => {
+                let progress = {
+                    let total = pending.len() + changelog.len();
+
+                    let bar = progress_bar(
+                        0.0..=1.0,
+                        changelog.len() as f32 / total as f32,
+                    )
+                    .style(progress_bar::secondary);
+
+                    let label = text!(
+                        "{amount_reviewed} / {total}",
+                        amount_reviewed = changelog.len()
+                    )
+                    .font(Font::MONOSPACE)
+                    .size(12);
+
+                    stack![bar, center(label)]
+                };
+
+                let form: Element<_> = match state {
+                    State::Loading(candidate) => {
+                        text!("Loading #{}...", candidate.id).into()
+                    }
+                    State::Loaded {
+                        pull_request,
+                        description,
+                        title,
+                        category,
+                    } => {
+                        let details = {
+                            let title = rich_text![
+                                span(&pull_request.title).size(24).link(
+                                    Message::OpenPullRequest(pull_request.id)
+                                ),
+                                span(format!(" by {}", pull_request.author))
+                                    .font(Font {
+                                        style: font::Style::Italic,
+                                        ..Font::default()
+                                    }),
+                            ]
+                            .font(Font::MONOSPACE);
+
+                            let description = markdown::view(
+                                description,
+                                markdown::Settings::default(),
+                                markdown::Style::from_palette(
+                                    self.theme().palette(),
+                                ),
+                            )
+                            .map(Message::UrlClicked);
+
+                            let labels =
+                                row(pull_request.labels.iter().map(|label| {
+                                    container(
+                                        text(label)
+                                            .size(10)
+                                            .font(Font::MONOSPACE),
+                                    )
+                                    .padding(5)
+                                    .style(container::rounded_box)
+                                    .into()
+                                }))
+                                .spacing(10)
+                                .wrap();
+
+                            column![
+                                title,
+                                labels,
+                                scrollable(description)
+                                    .spacing(10)
+                                    .width(Fill)
+                                    .height(Fill)
+                            ]
+                            .spacing(10)
+                        };
+
+                        let title = text_input(
+                            "Type a changelog entry title...",
+                            title,
+                        )
+                        .on_input(Message::TitleChanged);
+
+                        let category = pick_list(
+                            changelog::Category::ALL,
+                            Some(category),
+                            Message::CategorySelected,
+                        );
+
+                        let next = button("Next →")
+                            .on_press(Message::Next)
+                            .style(button::success);
+
+                        column![
+                            details,
+                            row![title, category, next].spacing(10)
+                        ]
+                        .spacing(10)
+                        .into()
+                    }
+                };
+
+                let preview: Element<_> = if preview.is_empty() {
+                    center(
+                        container(
+                            text("The changelog is empty... so far!").size(12),
+                        )
+                        .padding(10)
+                        .style(container::rounded_box),
+                    )
+                    .into()
+                } else {
+                    let content = container(
+                        scrollable(
+                            markdown::view(
+                                preview,
+                                markdown::Settings::with_text_size(12),
+                                markdown::Style::from_palette(
+                                    self.theme().palette(),
+                                ),
+                            )
+                            .map(Message::UrlClicked),
+                        )
+                        .spacing(10),
+                    )
+                    .width(Fill)
+                    .padding(10)
+                    .style(container::rounded_box);
+
+                    let copy = button(icon::copy().size(12))
+                        .on_press(Message::CopyPreview)
+                        .style(button::text);
+
+                    center(stack![content, container(copy).align_right(Fill)])
+                        .into()
+                };
+
+                let review = column![container(form).height(Fill), progress]
+                    .spacing(10)
+                    .width(FillPortion(2));
+
+                row![review, preview].spacing(10).padding(10).into()
+            }
+        }
+    }
+
+    fn theme(&self) -> Theme {
+        Theme::TokyoNightStorm
+    }
+}