initial commit

13 files changed, 1175 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..05dc674
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,20 @@
+[package]
+name = "kondou"
+version = "0.1.0"
+authors = ["Daniel <kingdread@gmx.de>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+image = "0.22"
+imageproc = "0.19"
+rusttype = "0.7"
+reqwest = "0.9"
+serde = "1.0"
+serde_json = "1.0"
+clap = "2.33"
+xdg = "2.2.0"
+quick-error = "1.2.0"
+itertools = "0.8.0"
+md5 = "0.7"
diff --git a/src/LiberationMono.ttf b/src/LiberationMono.ttf
new file mode 100644
index 0000000..1a39bc7
--- /dev/null
+++ b/src/LiberationMono.ttf
diff --git a/src/api/mod.rs b/src/api/mod.rs
new file mode 100644
index 0000000..6e1b457
--- /dev/null
+++ b/src/api/mod.rs
@@ -0,0 +1,205 @@
+//! This module is responsible for accessing the Guild Wars 2 API.
+//!
+//! It contains `Deserialize`able definitions for the required API responses, as well as a wrapper
+//! around the HTTP library. Note that only the required fields are modelled here, which means this
+//! does not provide a full-featured mapping for all API types.
+pub mod professions;
+pub mod skills;
+pub mod specializations;
+pub mod traits;
+
+pub use self::{
+    professions::Profession, skills::Skill, specializations::Specialization, traits::Trait,
+};
+
+use image::DynamicImage;
+use itertools::Itertools;
+use reqwest::{Client, Url};
+use serde::{de::DeserializeOwned, Serialize};
+use std::path::Path;
+
+use super::cache::{Cache, CacheError};
+
+/// The base URL of the official Guild Wars 2 API.
+const BASE_URL: &str = "https://api.guildwars2.com/v2/";
+
+quick_error! {
+    #[derive(Debug)]
+    pub enum ApiError {
+        SerializationError(err: serde_json::Error) {
+            cause(err)
+            from()
+        }
+        CacheError(err: CacheError) {
+            cause(err)
+            from()
+        }
+        HttpError(err: reqwest::Error) {
+            cause(err)
+            from()
+        }
+        ImageError(err: image::ImageError) {
+            cause(err)
+            from()
+        }
+    }
+}
+
+/// Trait for API objects that have an ID.
+///
+/// This is used by [`Api`](struct.Api.html) to properly retrieve and cache objects.
+trait HasId {
+    type Id: ToString + Eq + Clone;
+    fn get_id(&self) -> Self::Id;
+}
+
+/// The main API access struct.
+///
+/// This takes care of caching given the provided cache implementation, as well as keeping a HTTP
+/// connection pool around to re-use.
+pub struct Api {
+    cache: Box<dyn Cache>,
+    base_url: Url,
+    client: Client,
+}
+
+/// API access for the GW2 api.
+impl Api {
+    /// Create a new API instance with the given cache underlying.
+    pub fn new<C: 'static + Cache>(cache: C) -> Api {
+        Api {
+            cache: Box::new(cache),
+            base_url: Url::parse(BASE_URL).unwrap(),
+            client: Client::new(),
+        }
+    }
+
+    /// Combines the given endpoint with the `base_url` of this API.
+    fn make_url(&self, endpoint: &str) -> Url {
+        self.base_url.join(endpoint).expect("Invalid API endpoint")
+    }
+
+    /// Get and deserialize a cached value.
+    fn get_cached<T, P>(&mut self, name: P) -> Result<Option<T>, ApiError>
+    where
+        T: DeserializeOwned,
+        P: AsRef<Path>,
+    {
+        match self.cache.get(name.as_ref())? {
+            Some(data) => Ok(serde_json::from_slice(&data)?),
+            None => Ok(None),
+        }
+    }
+
+    /// Serialize and store a value in the cache.
+    fn save_cached<T, P>(&mut self, name: P, value: &T) -> Result<(), ApiError>
+    where
+        T: Serialize,
+        P: AsRef<Path>,
+    {
+        self.cache
+            .store(name.as_ref(), &serde_json::to_vec(value)?)?;
+        Ok(())
+    }
+
+    /// Retrieves a list of elements by their ID.
+    ///
+    /// This function first checks the cache if elements can be found there, and otherwise hits the
+    /// API.
+    fn get_multiple_cached<R>(
+        &mut self,
+        endpoint: &str,
+        cache_prefix: &str,
+        ids: &[R::Id],
+    ) -> Result<Vec<R>, ApiError>
+    where
+        R: HasId + DeserializeOwned + Serialize,
+    {
+        let mut result: Vec<R> = Vec::new();
+        let mut api_ids: Vec<R::Id> = Vec::new();
+
+        for id in ids {
+            let cache_path = format!("{}{}", cache_prefix, id.to_string());
+            match self.get_cached(cache_path)? {
+                Some(cached) => result.push(cached),
+                None => api_ids.push(id.clone()),
+            }
+        }
+
+        if api_ids.is_empty() {
+            return Ok(result);
+        }
+
+        let url = self.make_url(endpoint);
+        let api_arg = api_ids.iter().map(ToString::to_string).join(",");
+        let resp: Vec<R> = self
+            .client
+            .get(url)
+            .query(&[("ids", api_arg)])
+            .send()?
+            .json()?;
+        for result in &resp {
+            let cache_path = format!("{}{}", cache_prefix, result.get_id().to_string());
+            self.save_cached(cache_path, result)?;
+        }
+        result.extend(resp.into_iter());
+
+        Ok(result)
+    }
+
+    /// Retrieve a list of all professions using the professions endpoint.
+    pub fn get_profession_ids(&mut self) -> Result<Vec<String>, ApiError> {
+        if let Some(cached) = self.get_cached("profession_ids")? {
+            return Ok(cached);
+        }
+        let url = self.make_url("professions");
+        let resp = self.client.get(url).send()?.json()?;
+        self.save_cached("profession_ids", &resp)?;
+        Ok(resp)
+    }
+
+    /// Retrieve detailed information about the given professions.
+    ///
+    /// Professions that are found in the cache are taken from there. Therefore, the order of the
+    /// return vector is not guaranteed to be the same as the input order.
+    pub fn get_professions(&mut self, ids: &[String]) -> Result<Vec<Profession>, ApiError> {
+        self.get_multiple_cached("professions", "professions/", ids)
+    }
+
+    /// Retrieve detailed information about the given skills.
+    ///
+    /// Skills that are found in the cache are taken from there.
+    pub fn get_skills(&mut self, ids: &[u32]) -> Result<Vec<Skill>, ApiError> {
+        self.get_multiple_cached("skills", "skills/", ids)
+    }
+
+    /// Retrieve detailed information about the given specializations.
+    ///
+    /// Specializations that are found in the cache are taken from there.
+    pub fn get_specializations(&mut self, ids: &[u32]) -> Result<Vec<Specialization>, ApiError> {
+        self.get_multiple_cached("specializations", "specializations/", ids)
+    }
+
+    /// Retrieve detailed information about the given traits.
+    ///
+    /// Traits that are found in the cache are taken from there.
+    pub fn get_traits(&mut self, ids: &[u32]) -> Result<Vec<Trait>, ApiError> {
+        self.get_multiple_cached("traits", "traits/", ids)
+    }
+
+    /// Loads the image from the given URL.
+    ///
+    /// This automatically caches and also decodes the resulting data.
+    pub fn get_image(&mut self, url: &str) -> Result<DynamicImage, ApiError> {
+        let hashed_url = format!("images/{:x}", md5::compute(url.as_bytes()));
+        if let Some(data) = self.cache.get(Path::new(&hashed_url))? {
+            return Ok(image::load_from_memory(&data)?);
+        }
+
+        let mut img = Vec::new();
+        self.client.get(url).send()?.copy_to(&mut img)?;
+
+        self.cache.store(Path::new(&hashed_url), &img)?;
+        Ok(image::load_from_memory(&img)?)
+    }
+}
diff --git a/src/api/professions.rs b/src/api/professions.rs
new file mode 100644
index 0000000..2716a1a
--- /dev/null
+++ b/src/api/professions.rs
@@ -0,0 +1,36 @@
+//! Struct definitions for the professions API endpoint.
+//!
+//! * [Example](https://api.guildwars2.com/v2/professions/Engineer)
+//! * [Wiki](https://wiki.guildwars2.com/wiki/API:2/professions)
+
+use super::HasId;
+use serde::{Deserialize, Serialize};
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+pub struct Profession {
+    /// The profession id.
+    pub id: String,
+    /// The name of the profession.
+    pub name: String,
+    /// List of specialization ids.
+    pub specializations: Vec<u32>,
+    /// List of skills.
+    pub skills: Vec<Skill>,
+}
+
+impl HasId for Profession {
+    type Id = String;
+    fn get_id(&self) -> String {
+        self.id.clone()
+    }
+}
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+pub struct Skill {
+    /// The id of the skill.
+    pub id: u32,
+    /// The skill bar slot that this skill can be used in.
+    pub slot: String,
+    #[serde(rename = "type")]
+    pub typ: String,
+}
diff --git a/src/api/skills.rs b/src/api/skills.rs
new file mode 100644
index 0000000..9c692e1
--- /dev/null
+++ b/src/api/skills.rs
@@ -0,0 +1,24 @@
+//! Struct definitions for the skills API endpoint.
+//!
+//! * [Example](https://api.guildwars2.com/v2/skills/14375)
+//! * [Wiki](https://wiki.guildwars2.com/wiki/API:2/skills)
+
+use super::HasId;
+use serde::{Deserialize, Serialize};
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+pub struct Skill {
+    /// The skill id.
+    pub id: u32,
+    /// The skill name.
+    pub name: String,
+    /// A URL to an icon of the skill.
+    pub icon: String,
+}
+
+impl HasId for Skill {
+    type Id = u32;
+    fn get_id(&self) -> u32 {
+        self.id
+    }
+}
diff --git a/src/api/specializations.rs b/src/api/specializations.rs
new file mode 100644
index 0000000..97fc289
--- /dev/null
+++ b/src/api/specializations.rs
@@ -0,0 +1,34 @@
+//! Struct definitions for the specializations API endpoint.
+//!
+//! * [Example](https://api.guildwars2.com/v2/specializations/1)
+//! * [Wiki](https://wiki.guildwars2.com/wiki/API:2/specializations)
+
+use super::HasId;
+use serde::{Deserialize, Serialize};
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+pub struct Specialization {
+    /// The specialization's ID.
+    pub id: u32,
+    /// The name of the specialization.
+    pub name: String,
+    /// The profession that this specialization belongs to.
+    pub profession: String,
+    /// `true` if this specialization is an elite specialization, `false` otherwise.
+    pub elite: bool,
+    /// A URL to an icon of the specialization.
+    pub icon: String,
+    /// An URL to the background image of the specialization.
+    pub background: String,
+    /// Contains a list of IDs specifying the minor traits in the specialization.
+    pub minor_traits: Vec<u32>,
+    /// Contains a list of IDs specifying the major traits in the specialization.
+    pub major_traits: Vec<u32>,
+}
+
+impl HasId for Specialization {
+    type Id = u32;
+    fn get_id(&self) -> u32 {
+        self.id
+    }
+}
diff --git a/src/api/traits.rs b/src/api/traits.rs
new file mode 100644
index 0000000..194d061
--- /dev/null
+++ b/src/api/traits.rs
@@ -0,0 +1,40 @@
+//! Struct definitions for the traits API endpoint.
+//!
+//! * [Example](https://api.guildwars2.com/v2/traits/214)
+//! * [Wiki](https://wiki.guildwars2.com/wiki/API:2/traits)
+
+use super::HasId;
+use serde::{Deserialize, Serialize};
+
+#[derive(Deserialize, Serialize, Debug, Clone)]
+pub struct Trait {
+    /// The trait id.
+    pub id: u32,
+    /// The trait name.
+    pub name: String,
+    /// The trait's icon URL.
+    pub icon: String,
+    /// The trait description.
+    pub description: String,
+    /// The id of the specialization this trait belongs to.
+    pub specialization: u32,
+    /// The trait's tier, as a value from 1-3.
+    ///
+    /// Elite specializations also contain a tier 0 minor trait, describing which weapon the elite
+    /// specialization gains access to.
+    pub tier: u32,
+    pub slot: Slot,
+}
+
+impl HasId for Trait {
+    type Id = u32;
+    fn get_id(&self) -> u32 {
+        self.id
+    }
+}
+
+#[derive(Deserialize, Serialize, Debug, PartialEq, Eq, Hash, Copy, Clone)]
+pub enum Slot {
+    Major,
+    Minor,
+}
diff --git a/src/bt.rs b/src/bt.rs
new file mode 100644
index 0000000..3485448
--- /dev/null
+++ b/src/bt.rs
@@ -0,0 +1,160 @@
+use super::api::{Skill, Specialization};
+use std::{fmt, str::FromStr};
+
+/// The profession of the template.
+///
+/// Can be cast to an `u8` to get the right ID for building chat links.
+#[repr(u8)]
+#[derive(Debug, PartialEq, Eq, Hash, Copy, Clone)]
+pub enum Profession {
+    Guardian = 1,
+    Warrior = 2,
+    Engineer = 3,
+    Ranger = 4,
+    Thief = 5,
+    Elementalist = 6,
+    Mesmer = 7,
+    Necromancer = 8,
+    Revenant = 9,
+}
+
+impl fmt::Display for Profession {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self, f)
+    }
+}
+
+impl FromStr for Profession {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "Guardian" => Ok(Profession::Guardian),
+            "Warrior" => Ok(Profession::Warrior),
+            "Engineer" => Ok(Profession::Engineer),
+            "Ranger" => Ok(Profession::Ranger),
+            "Thief" => Ok(Profession::Thief),
+            "Elementalist" => Ok(Profession::Elementalist),
+            "Mesmer" => Ok(Profession::Mesmer),
+            "Necromancer" => Ok(Profession::Necromancer),
+            "Revenant" => Ok(Profession::Revenant),
+            _ => Err(()),
+        }
+    }
+}
+
+/// Represents the selected trait.
+#[repr(u8)]
+#[derive(Debug, PartialEq, Eq, Hash, Copy, Clone)]
+pub enum TraitChoice {
+    None = 0,
+    Top = 1,
+    Middle = 2,
+    Bottom = 3,
+}
+
+impl FromStr for TraitChoice {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let lower = s.to_lowercase();
+        match &lower as &str {
+            "" | "none" => Ok(TraitChoice::None),
+            "top" => Ok(TraitChoice::Top),
+            "mid" | "middle" => Ok(TraitChoice::Middle),
+            "bot" | "bottom" => Ok(TraitChoice::Bottom),
+            _ => Err(()),
+        }
+    }
+}
+
+/// Represents a traitline.
+///
+/// A traitline consists of the chosen specialization including 3 possible trait choices.
+pub type Traitline = (Specialization, [TraitChoice; 3]);
+
+pub const SKILL_COUNT: usize = 5;
+pub const TRAITLINE_COUNT: usize = 3;
+
+/// Represents a build template.
+///
+/// This struct is made with the same limitations as the game imposes. That is, even though the
+/// renderer can support more than three traitlines, this template will only allow you to take
+/// three.
+#[derive(Debug)]
+pub struct BuildTemplate {
+    /// Profession of this build.
+    profession: Profession,
+    /// The skills of the build.
+    ///
+    /// Each slot can either contain a slot or be empty. A maximum of 5 skills are allowed (heal, 3
+    /// utilities and elite).
+    skills: [Option<Skill>; SKILL_COUNT],
+    /// The traitlines of the build.
+    traitlines: [Option<Traitline>; TRAITLINE_COUNT],
+}
+
+impl BuildTemplate {
+    /// Returns a template without any skills or traitlines.
+    pub fn empty(profession: Profession) -> BuildTemplate {
+        BuildTemplate {
+            profession,
+            skills: [None, None, None, None, None],
+            traitlines: [None, None, None],
+        }
+    }
+
+    /// Creates a template with the given skills and traitlines.
+    ///
+    /// If there are more than 5 skills or 3 traitlines given, the function will return `None`.
+    pub fn new(
+        profession: Profession,
+        skills: &[Skill],
+        traitlines: &[Traitline],
+    ) -> Option<BuildTemplate> {
+        if skills.len() > SKILL_COUNT {
+            return None;
+        }
+        if traitlines.len() > TRAITLINE_COUNT {
+            return None;
+        }
+        let mut skill_array = [None, None, None, None, None];
+        for (i, skill) in skills.iter().enumerate() {
+            skill_array[i] = Some(skill.clone());
+        }
+        let mut trait_array = [None, None, None];
+        for (i, traitline) in traitlines.iter().enumerate() {
+            trait_array[i] = Some(traitline.clone());
+        }
+        Some(BuildTemplate {
+            profession,
+            skills: skill_array,
+            traitlines: trait_array,
+        })
+    }
+
+    /// Returns the profession of this build.
+    pub fn profession(&self) -> Profession {
+        self.profession
+    }
+
+    /// Returns the skills of this build.
+    pub fn skills(&self) -> &[Option<Skill>] {
+        &self.skills
+    }
+
+    /// Returns the number of actually equipped skills.
+    pub fn skill_count(&self) -> u32 {
+        self.skills.iter().filter(|x| x.is_some()).count() as u32
+    }
+
+    /// Returns the traitlines of this build.
+    pub fn traitlines(&self) -> &[Option<Traitline>] {
+        &self.traitlines
+    }
+
+    /// Returns the number of actually equipped specializations.
+    pub fn traitline_count(&self) -> u32 {
+        self.traitlines.iter().filter(|x| x.is_some()).count() as u32
+    }
+}
diff --git a/src/cache.rs b/src/cache.rs
new file mode 100644
index 0000000..f64b45a
--- /dev/null
+++ b/src/cache.rs
@@ -0,0 +1,78 @@
+//! Caching support to prevent hitting the API a lot.
+use std::fs::File;
+use std::io::prelude::*;
+use std::path::Path;
+
+use xdg::BaseDirectories;
+
+use super::APP_NAME;
+
+quick_error! {
+    #[derive(Debug)]
+    pub enum CacheError {
+        Io(err: std::io::Error) {
+            cause(err)
+            from()
+        }
+    }
+}
+
+/// A generic cache.
+pub trait Cache {
+    fn store(&mut self, path: &Path, data: &[u8]) -> Result<(), CacheError>;
+    fn get(&mut self, path: &Path) -> Result<Option<Vec<u8>>, CacheError>;
+}
+
+/// A cache that stores files in the XDG specified cache location.
+pub struct FileCache {
+    dirs: BaseDirectories,
+}
+
+impl FileCache {
+    /// Create a new file backed cache.
+    pub fn new() -> Self {
+        let dirs = BaseDirectories::with_prefix(APP_NAME).unwrap();
+        FileCache { dirs }
+    }
+}
+
+impl Cache for FileCache {
+    fn store(&mut self, path: &Path, data: &[u8]) -> Result<(), CacheError> {
+        let cache_path = self.dirs.place_cache_file(path).unwrap();
+        let mut f = File::create(cache_path)?;
+        f.write_all(data)?;
+        Ok(())
+    }
+
+    fn get(&mut self, path: &Path) -> Result<Option<Vec<u8>>, CacheError> {
+        let cache_path = self.dirs.find_cache_file(path);
+        match cache_path {
+            Some(p) => {
+                let mut f = File::open(p)?;
+                let mut buffer = Vec::new();
+                f.read_to_end(&mut buffer)?;
+                Ok(Some(buffer))
+            }
+            None => Ok(None),
+        }
+    }
+}
+
+/// A cache that does nothing.
+struct NoopCache;
+
+impl NoopCache {
+    pub fn new() -> Self {
+        NoopCache
+    }
+}
+
+impl Cache for NoopCache {
+    fn store(&mut self, _path: &Path, _data: &[u8]) -> Result<(), CacheError> {
+        Ok(())
+    }
+
+    fn get(&mut self, _path: &Path) -> Result<Option<Vec<u8>>, CacheError> {
+        Ok(None)
+    }
+}
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..9ffa1eb
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,252 @@
+extern crate clap;
+extern crate image;
+extern crate imageproc;
+extern crate itertools;
+extern crate md5;
+extern crate reqwest;
+extern crate rusttype;
+extern crate xdg;
+#[macro_use]
+extern crate quick_error;
+
+use std::error::Error as StdError;
+use std::fmt;
+
+mod api;
+mod bt;
+mod cache;
+mod render;
+
+use clap::{App, Arg, ArgMatches};
+
+use api::{Api, Profession, Skill};
+use bt::{BuildTemplate, TraitChoice, Traitline};
+
+const APP_NAME: &str = "kondou";
+
+#[derive(Debug, Clone)]
+enum Error {
+    ProfessionNotFound(String),
+    SkillIdNotFound(u32),
+    SkillNotFound(String),
+    SpecializationNotFound(String),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Error::ProfessionNotFound(ref name) => {
+                write!(f, "the profession '{}' could not be found", name)
+            }
+            Error::SkillIdNotFound(id) => write!(f, "the skill with the ID '{}' was not found", id),
+            Error::SkillNotFound(ref name) => {
+                write!(f, "the skill with the name '{}' was not found", name)
+            }
+            Error::SpecializationNotFound(ref name) => write!(
+                f,
+                "the specialization with the name '{}' was not found",
+                name
+            ),
+        }
+    }
+}
+
+impl StdError for Error {}
+
+type MainResult<T> = Result<T, Box<dyn StdError>>;
+
+fn find_profession(api: &mut Api, name: &str) -> MainResult<Profession> {
+    let profession_ids = api.get_profession_ids()?;
+    let lower_name = name.to_lowercase();
+    let profession_id = profession_ids
+        .iter()
+        .find(|id| id.to_lowercase() == lower_name)
+        .ok_or_else(|| Error::ProfessionNotFound(name.to_owned()))?
+        .clone();
+
+    Ok(api.get_professions(&[profession_id])?.remove(0))
+}
+
+fn resolve_skill(api: &mut Api, profession: &Profession, text: &str) -> MainResult<Skill> {
+    // Try it as an ID first
+    let numeric = text.parse::<u32>();
+    if let Ok(num_id) = numeric {
+        let exists = profession.skills.iter().any(|s| s.id == num_id);
+        if exists {
+            return Ok(api.get_skills(&[num_id])?.remove(0));
+        } else {
+            return Err(Error::SkillIdNotFound(num_id).into());
+        }
+    }
+
+    // Check all names of the profession skills
+    let all_ids = profession.skills.iter().map(|s| s.id).collect::<Vec<_>>();
+    let all_skills = api.get_skills(&all_ids)?;
+    let lower_text = text.to_lowercase();
+    all_skills
+        .into_iter()
+        .find(|s| s.name.to_lowercase().contains(&lower_text))
+        .ok_or_else(|| Error::SkillNotFound(text.to_owned()).into())
+}
+
+fn resolve_traitline(api: &mut Api, profession: &Profession, text: &str) -> MainResult<Traitline> {
+    let parts = text.split(':').collect::<Vec<_>>();
+    assert_eq!(
+        parts.len(),
+        4,
+        "invalid text format passed to resolve_traitline"
+    );
+
+    let name = parts[0];
+    let lower_name = name.to_lowercase();
+    let spec = api
+        .get_specializations(&profession.specializations)?
+        .into_iter()
+        .find(|s| s.name.to_lowercase() == lower_name)
+        .ok_or_else(|| Error::SpecializationNotFound(name.to_owned()))?;
+
+    let mut choices = [TraitChoice::None; 3];
+    for (i, text_choice) in parts.iter().skip(1).enumerate() {
+        let choice = text_choice
+            .parse()
+            .expect("Argument validation failed us, there is an invalid value here");
+        choices[i] = choice;
+    }
+    Ok((spec, choices))
+}
+
+fn run_searching(api: &mut Api, matches: &ArgMatches) -> MainResult<BuildTemplate> {
+    let requested_profession = matches
+        .value_of("profession")
+        .expect("clap handles missing argument");
+
+    let profession = find_profession(api, requested_profession)?;
+
+    let skills = matches
+        .values_of("skill")
+        .map(Iterator::collect::<Vec<_>>)
+        .unwrap_or_default()
+        .into_iter()
+        .map(|s| resolve_skill(api, &profession, s))
+        .collect::<Result<Vec<_>, _>>()?;
+
+    let traitlines = matches
+        .values_of("traitline")
+        .map(Iterator::collect::<Vec<_>>)
+        .unwrap_or_default()
+        .into_iter()
+        .map(|t| resolve_traitline(api, &profession, t))
+        .collect::<Result<Vec<_>, _>>()?;
+
+    assert!(skills.len() <= bt::SKILL_COUNT, "got too many skills");
+    assert!(
+        traitlines.len() <= bt::TRAITLINE_COUNT,
+        "got too many traitlines"
+    );
+
+    let build = BuildTemplate::new(
+        profession
+            .name
+            .parse()
+            .expect("Profession object has unparseable name"),
+        &skills,
+        &traitlines,
+    )
+    .expect("BuildTemplate could not be constructed");
+
+    Ok(build)
+}
+
+fn validate_traitline_format(input: String) -> Result<(), String> {
+    let parts = input.split(':').collect::<Vec<_>>();
+    if parts.len() != 4 {
+        return Err("traitline format is line:trait_1:trait_2:trait_3".to_owned());
+    }
+
+    for part in parts.iter().skip(1) {
+        let parsed = part.parse::<TraitChoice>();
+        if parsed.is_err() {
+            return Err(format!(
+                "{} is not a valid trait. Use top, middle or bottom.",
+                part
+            ));
+        }
+    }
+
+    Ok(())
+}
+
+fn run() -> MainResult<()> {
+    let matches = App::new(APP_NAME)
+        .version("0.1")
+        .author("Daniel <kingdread@gmx.de>")
+        .about("Renders GW2 skills and traits.")
+        .arg(
+            Arg::with_name("profession")
+                .help("Selects which profession to use.")
+                .required_unless("chatlink"),
+        )
+        .arg(
+            Arg::with_name("skill")
+                .help("Selects a skill based on either the name or the ID.")
+                .takes_value(true)
+                .number_of_values(1)
+                .long("skill")
+                .short("s")
+                .multiple(true)
+                .max_values(bt::SKILL_COUNT as u64),
+        )
+        .arg(
+            Arg::with_name("traitline")
+                .help("Selects a traitline.")
+                .takes_value(true)
+                .number_of_values(1)
+                .long("traitline")
+                .short("t")
+                .multiple(true)
+                .validator(validate_traitline_format)
+                .max_values(bt::TRAITLINE_COUNT as u64),
+        )
+        .arg(
+            Arg::with_name("chatlink")
+                .help("Specifies a chat link to parse.")
+                .short("c")
+                .long("chatlink")
+                .takes_value(true)
+                .conflicts_with_all(&["profession", "skill"]),
+        )
+        .arg(
+            Arg::with_name("outfile")
+                .help("Specifies the output filename")
+                .short("o")
+                .long("outfile")
+                .default_value("buildtemplate.png")
+                .takes_value(true),
+        )
+        .get_matches();
+
+    let mut api = Api::new(cache::FileCache::new());
+    let build = match matches.is_present("chatlink") {
+        false => run_searching(&mut api, &matches)?,
+        true => unimplemented!(),
+    };
+
+    let mut renderer = render::Renderer::new(&mut api, Default::default());
+    let img = renderer.render_buildtemplate(&build).unwrap();
+    let filename = matches.value_of("outfile").unwrap();
+    img.save(filename)?;
+
+    Ok(())
+}
+
+fn main() {
+    let result = run();
+    if let Err(e) = result {
+        eprintln!("[Error] {}", e);
+        let mut source = e.source();
+        while let Some(s) = source {
+            eprintln!("  caused by {}", s);
+            source = s.source();
+        }
+    }
+}
diff --git a/src/minor_trait_mask.png b/src/minor_trait_mask.png
new file mode 100644
index 0000000..4fed74d
--- /dev/null
+++ b/src/minor_trait_mask.png
diff --git a/src/render.rs b/src/render.rs
new file mode 100644
index 0000000..77a847f
--- /dev/null
+++ b/src/render.rs
@@ -0,0 +1,325 @@
+use super::api::{Api, ApiError, Skill, Specialization, Trait};
+use super::bt::{BuildTemplate, TraitChoice, Traitline};
+use image::{imageops, DynamicImage, GenericImage, GenericImageView, ImageBuffer, Rgba, RgbaImage};
+use imageproc::drawing::{self, Point};
+use rusttype::{Font, Scale, SharedBytes};
+
+quick_error! {
+    #[derive(Debug)]
+    pub enum RenderError {
+        ApiError(err: ApiError) {
+            cause(err)
+            from()
+        }
+        ImageError(err: image::ImageError) {
+            cause(err)
+            from()
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct RenderOptions {
+    skill_size: u32,
+    traitline_height: u32,
+    traitline_width: u32,
+    traitline_brightness: i32,
+    traitline_x_offset: u32,
+    trait_size: u32,
+    line_color: Rgba<u8>,
+    line_height: u32,
+    font: Font<'static>,
+    text_color: Rgba<u8>,
+    text_size: u32,
+    background_color: Rgba<u8>,
+    render_specialization_names: bool,
+    skill_offset: u32,
+}
+
+impl Default for RenderOptions {
+    fn default() -> Self {
+        RenderOptions {
+            skill_size: 100,
+            traitline_height: 160,
+            traitline_width: 550,
+            traitline_brightness: 100,
+            traitline_x_offset: 0,
+            trait_size: 30,
+            line_color: Rgba([0, 0, 0, 255]),
+            line_height: 4,
+            font: Font::from_bytes(SharedBytes::ByRef(include_bytes!("LiberationMono.ttf")))
+                .expect("Invalid font data for default font"),
+            text_color: Rgba([0, 0, 0, 255]),
+            text_size: 20,
+            background_color: Rgba([0, 0, 0, 0]),
+            render_specialization_names: true,
+            skill_offset: 30,
+        }
+    }
+}
+
+const BG_CROP_HEIGHT: u32 = 160;
+const BG_CROP_WIDTH: u32 = 550;
+
+pub struct Renderer<'r> {
+    api: &'r mut Api,
+    options: RenderOptions,
+    minor_mask: DynamicImage,
+}
+
+impl<'r> Renderer<'r> {
+    /// Create a new renderer using the given API.
+    pub fn new(api: &mut Api, options: RenderOptions) -> Renderer<'_> {
+        let minor_mask = image::load_from_memory(include_bytes!("minor_trait_mask.png"))
+            .expect("Mask image could not be loaded")
+            .resize(
+                options.trait_size,
+                options.trait_size,
+                imageops::FilterType::CatmullRom,
+            );
+        Renderer {
+            api,
+            options,
+            minor_mask,
+        }
+    }
+
+    pub fn render_skills(&mut self, skills: &[Option<Skill>]) -> Result<RgbaImage, RenderError> {
+        let mut buffer = ImageBuffer::new(
+            skills.len() as u32 * self.options.skill_size,
+            self.options.skill_size,
+        );
+        for (i, skill) in skills.iter().enumerate() {
+            if let Some(skill) = skill {
+                let img = self.api.get_image(&skill.icon)?.resize(
+                    self.options.skill_size,
+                    self.options.skill_size,
+                    imageops::FilterType::CatmullRom,
+                );
+                buffer.copy_from(&img, i as u32 * self.options.skill_size, 0);
+            }
+        }
+        Ok(buffer)
+    }
+
+    fn render_minor_trait(
+        &mut self,
+        buffer: &mut RgbaImage,
+        minor: &Trait,
+    ) -> Result<(), RenderError> {
+        let minor_img = self.api.get_image(&minor.icon)?.resize(
+            self.options.trait_size,
+            self.options.trait_size,
+            imageops::FilterType::CatmullRom,
+        );
+        let minor_img = imageproc::map::map_pixels(&minor_img, |x, y, p| {
+            let alpha = self.minor_mask.get_pixel(x, y)[3];
+            Rgba([p[0], p[1], p[2], alpha])
+        });
+        let y_pos = (buffer.height() - minor_img.height()) / 2;
+        let x_slice = (buffer.width() - self.options.traitline_x_offset) / 6;
+        let x_pos = 2 * (minor.tier - 1) * x_slice
+            + (x_slice - minor_img.width()) / 2
+            + self.options.traitline_x_offset;
+        imageops::overlay(buffer, &minor_img, x_pos, y_pos);
+        Ok(())
+    }
+
+    fn render_major_trait(
+        &mut self,
+        buffer: &mut RgbaImage,
+        major: &Trait,
+        vertical_pos: u8,
+        chosen: bool,
+    ) -> Result<(), RenderError> {
+        let major_img = self.api.get_image(&major.icon)?.resize(
+            self.options.trait_size,
+            self.options.trait_size,
+            imageops::FilterType::CatmullRom,
+        );
+        let major_img = if !chosen {
+            major_img.grayscale()
+        } else {
+            major_img
+        };
+        let y_slice = buffer.height() / 3;
+        let y_pos = vertical_pos as u32 * y_slice + (y_slice - major_img.height()) / 2;
+        let x_slice = (buffer.width() - self.options.traitline_x_offset) / 6;
+        let x_pos = 2 * (major.tier - 1) * x_slice
+            + x_slice
+            + (x_slice - major_img.width()) / 2
+            + self.options.traitline_x_offset;
+        imageops::overlay(buffer, &major_img, x_pos, y_pos);
+        Ok(())
+    }
+
+    fn render_line(
+        &mut self,
+        buffer: &mut RgbaImage,
+        tier: u8,
+        choice: TraitChoice,
+    ) -> Result<(), RenderError> {
+        if choice == TraitChoice::None {
+            return Ok(());
+        }
+
+        let x_slice = (buffer.width() - self.options.traitline_x_offset) / 6;
+        let start_x = 2 * tier as u32 * x_slice
+            + (x_slice + self.options.trait_size) / 2
+            + self.options.traitline_x_offset;
+        let end_x = start_x + x_slice - self.options.trait_size;
+        let start_y = (buffer.height() - self.options.line_height) / 2;
+        let y_slice = buffer.height() / 3;
+        let end_y = y_slice * (choice as u32 - 1) + (y_slice - self.options.line_height) / 2;
+
+        drawing::draw_convex_polygon_mut(
+            buffer,
+            &[
+                Point::new(start_x as i32, start_y as i32),
+                Point::new(
+                    start_x as i32,
+                    start_y as i32 + self.options.line_height as i32,
+                ),
+                Point::new(end_x as i32, end_y as i32 + self.options.line_height as i32),
+                Point::new(end_x as i32, end_y as i32),
+            ],
+            self.options.line_color,
+        );
+        if tier == 2 {
+            return Ok(());
+        }
+
+        drawing::draw_convex_polygon_mut(
+            buffer,
+            &[
+                Point::new(
+                    2 * x_slice as i32 + start_x as i32 - self.options.trait_size as i32,
+                    start_y as i32,
+                ),
+                Point::new(
+                    2 * x_slice as i32 + start_x as i32 - self.options.trait_size as i32,
+                    start_y as i32 + self.options.line_height as i32,
+                ),
+                Point::new(
+                    self.options.trait_size as i32 + end_x as i32,
+                    end_y as i32 + self.options.line_height as i32,
+                ),
+                Point::new(self.options.trait_size as i32 + end_x as i32, end_y as i32),
+            ],
+            self.options.line_color,
+        );
+
+        Ok(())
+    }
+
+    pub fn render_traitline(&mut self, traitline: &Traitline) -> Result<RgbaImage, RenderError> {
+        let (spec, choices) = traitline;
+        let mut background = self.api.get_image(&spec.background)?;
+        let mut buffer = background
+            .crop(
+                0,
+                background.height() - BG_CROP_HEIGHT,
+                BG_CROP_WIDTH,
+                BG_CROP_HEIGHT,
+            )
+            .brighten(self.options.traitline_brightness)
+            .resize(
+                self.options.traitline_width,
+                self.options.traitline_height,
+                imageops::FilterType::CatmullRom,
+            )
+            .to_rgba();
+
+        let minor_traits = self.api.get_traits(&spec.minor_traits)?;
+        for minor in &minor_traits {
+            self.render_minor_trait(&mut buffer, &minor)?;
+        }
+
+        let major_traits = self.api.get_traits(&spec.major_traits)?;
+        for (i, major) in major_traits.iter().enumerate() {
+            let choice = choices[major.tier as usize - 1];
+            let vert_pos = (i % 3) as u8;
+            let chosen = choice as u8 == vert_pos + 1;
+            self.render_major_trait(&mut buffer, &major, vert_pos, chosen)?;
+        }
+
+        for (tier, choice) in choices.iter().enumerate() {
+            self.render_line(&mut buffer, tier as u8, *choice)?;
+        }
+        Ok(buffer)
+    }
+
+    pub fn render_specialization_name(
+        &mut self,
+        specialization: &Specialization,
+    ) -> Result<RgbaImage, RenderError> {
+        let scale = self.options.text_size;
+        let mut buffer = ImageBuffer::new(self.options.traitline_width, scale);
+        drawing::draw_text_mut(
+            &mut buffer,
+            self.options.text_color,
+            0,
+            0,
+            Scale {
+                x: scale as f32,
+                y: scale as f32,
+            },
+            &self.options.font,
+            &specialization.name,
+        );
+        Ok(buffer)
+    }
+
+    pub fn render_buildtemplate(
+        &mut self,
+        build: &BuildTemplate,
+    ) -> Result<RgbaImage, RenderError> {
+        let images = self.construct_parts(build)?;
+        self.merge_parts(&images)
+    }
+
+    fn construct_parts(&mut self, build: &BuildTemplate) -> Result<Vec<RgbaImage>, RenderError> {
+        let mut images: Vec<RgbaImage> = Vec::new();
+
+        for traitline in build.traitlines().iter().filter(|x| x.is_some()) {
+            let traitline = traitline.as_ref().unwrap();
+            if self.options.render_specialization_names {
+                let header = self.render_specialization_name(&traitline.0)?;
+                images.push(header);
+            }
+            let inner = self.render_traitline(&traitline)?;
+            images.push(inner);
+        }
+
+        let needs_space = build.skill_count() > 0 && build.traitline_count() > 0;
+        if needs_space {
+            let separator = ImageBuffer::from_pixel(
+                self.options.traitline_width,
+                self.options.skill_offset,
+                self.options.background_color,
+            );
+            images.push(separator);
+        }
+
+        if build.skill_count() > 0 {
+            let skills = self.render_skills(build.skills())?;
+            images.push(skills);
+        }
+
+        Ok(images)
+    }
+
+    fn merge_parts(&mut self, images: &[RgbaImage]) -> Result<RgbaImage, RenderError> {
+        let width = images.iter().map(RgbaImage::width).max().unwrap();
+        let height = images.iter().map(RgbaImage::height).sum();
+        let mut buffer = ImageBuffer::from_pixel(width, height, self.options.background_color);
+        let mut pos_y = 0;
+
+        for image in images {
+            imageops::overlay(&mut buffer, image, 0, pos_y);
+            pos_y += image.height();
+        }
+
+        Ok(buffer)
+    }
+}