1 files changed, 56 insertions, 3 deletions

diff --git a/src/context.rs b/src/context.rs
index 55f3f97..925db0b 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -1,9 +1,13 @@
-use structopt::StructOpt;
-use serde::Deserialize;
 use std::collections::HashMap;
 use std::fs;
 use std::io;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
+
+use structopt::StructOpt;
+use serde::Deserialize;
+use tera::{Tera, Filter, Value};
+
+const TMPL_FILES: &'static [&'static str] = &["index.html"];
 
 #[derive(Debug, StructOpt)]
 #[structopt(name = "gallery")]
@@ -30,6 +34,7 @@ pub enum ConfigError {
     Reading(io::Error),
     Parsing(serde_yaml::Error),
     CompilePattern(glob::PatternError),
+    CompileTemplate(tera::Error),
 }
 
 #[derive(Deserialize, Debug)]
@@ -41,11 +46,17 @@ pub struct Config {
     pub imageglob_compiled: glob::Pattern,
 }
 
+struct ReltoFilter {
+    dir: PathBuf,
+}
+
 #[derive(Debug)]
 pub struct Context {
     pub options: Options,
     pub config: Config,
     pub imgdir: PathBuf,
+
+    pub tmpl: Tera,
 }
 
 impl Context {
@@ -61,10 +72,22 @@ impl Context {
             }
         }
 
+        // Compile templates
+        let mut tera = Tera::default();
+        let tmpl_dir = opts.load.join("templates");
+        TMPL_FILES.iter().map(|fname| -> Result<(), ConfigError> {
+            let path = tmpl_dir.join(fname);
+            tera.add_template_file(path, Some(fname))?;
+            Ok(())
+        }).collect::<Result<(), ConfigError>>()?;
+
+        tera.register_filter("relto_build", ReltoFilter::new(&opts.builddir));
+
         Ok(Context {
             options: opts,
             config: config,
             imgdir: imgdir,
+            tmpl: tera,
         })
     }
 
@@ -83,6 +106,30 @@ impl Context {
     }
 }
 
+impl ReltoFilter {
+    pub fn new(dir: &Path) -> Self {
+        ReltoFilter {
+            dir: dir.to_path_buf(),
+        }
+    }
+}
+
+impl Filter for ReltoFilter {
+    fn filter(&self, value: &Value, _: &HashMap<String, tera::Value>) -> tera::Result<Value> {
+        if let Value::String(path) = value {
+            let path = PathBuf::from(path);
+            match path.strip_prefix(&self.dir) {
+                Ok(relto) => Ok(Value::String(relto.to_string_lossy().to_string())),
+                Err(err) => Err(tera::Error::call_filter("relto", err)),
+            }
+        } else {
+            Err(tera::Error::msg("Input to relto filter must be string"))
+        }
+    }
+
+    fn is_safe(&self) -> bool { true }
+}
+
 impl Config {
     fn load_from_file(path: &PathBuf) -> Result<Config, ConfigError> {
         let content = fs::read_to_string(path)?;
@@ -122,3 +169,9 @@ impl From<glob::PatternError> for ConfigError {
         ConfigError::CompilePattern(error)
     }
 }
+
+impl From<tera::Error> for ConfigError {
+    fn from(error: tera::Error) -> Self {
+        ConfigError::CompileTemplate(error)
+    }
+}