feat(ui): add support for customizing input_header, preview_header and preview_footer

This PR adds support for customizing

* input_header
* preview_header
* preview_footer

all the items are of type MultiTemplate, this gives some flexibility
when showing the selected value, let's say on the preview header, if
it's long or you want only a section

---------

Co-authored-by: alexandre pasmantier <alex.pasmant@gmail.com>

Cargo.lock

@@ -545,6 +545,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "deranged"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c9e6a11ca8224451684bc0d7d5a7adbf8f2fd6887261a1cfc3c0432f9d4068e"
+dependencies = [
+ "powerfmt",
+ "serde",
+]
+
 [[package]]
 name = "devicons"
 version = "0.6.12"
@@ -591,6 +601,12 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "75b325c5dbd37f80359721ad39aca5a29fb04c89279657cffdda8736d0c0b9d2"
 
+[[package]]
+name = "dyn-clone"
+version = "1.0.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1c7a8fb8a9fbf66c1f703fe16184d10ca0ee9d23be5b4436400408ba54a95005"
+
 [[package]]
 name = "either"
 version = "1.15.0"
@@ -774,6 +790,12 @@ dependencies = [
  "crunchy",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
+
 [[package]]
 name = "hashbrown"
 version = "0.15.2"
@@ -797,6 +819,12 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fbd780fe5cc30f81464441920d82ac8740e2e46b29a6fad543ddd075229ce37e"
 
+[[package]]
+name = "hex"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
+
 [[package]]
 name = "http"
 version = "1.3.1"
@@ -860,6 +888,17 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b9e0384b61958566e926dc50660321d12159025e767c18e043daf26b70104c39"
 
+[[package]]
+name = "indexmap"
+version = "1.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd070e393353796e801d209ad339e89596eb4c8d430d18ede6a1cced8fafbd99"
+dependencies = [
+ "autocfg",
+ "hashbrown 0.12.3",
+ "serde",
+]
+
 [[package]]
 name = "indexmap"
 version = "2.9.0"
@@ -867,7 +906,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cea70ddb795996207ad57735b50c5982d8844f38ba9ee5f1aedcfb708a2aa11e"
 dependencies = [
  "equivalent",
- "hashbrown",
+ "hashbrown 0.15.2",
+ "serde",
 ]
 
 [[package]]
@@ -1019,7 +1059,7 @@ version = "0.12.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "234cf4f4a04dc1f57e24b96cc0cd600cf2af460d4161ac5ecdd0af8e1f3b2a38"
 dependencies = [
- "hashbrown",
+ "hashbrown 0.15.2",
 ]
 
 [[package]]
@@ -1117,6 +1157,12 @@ dependencies = [
  "unicode-segmentation",
 ]
 
+[[package]]
+name = "num-conv"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51d515d32fb182ee37cda2ccdcb92950d6a3c2893aa280e540671c2cd0f3b1d9"
+
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -1311,6 +1357,12 @@ dependencies = [
  "winreg",
 ]
 
+[[package]]
+name = "powerfmt"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.94"
@@ -1397,6 +1449,26 @@ dependencies = [
  "thiserror 2.0.12",
 ]
 
+[[package]]
+name = "ref-cast"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a0ae411dbe946a674d89546582cea4ba2bb8defac896622d6496f14c23ba5cf"
+dependencies = [
+ "ref-cast-impl",
+]
+
+[[package]]
+name = "ref-cast-impl"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1165225c21bff1f3bbce98f5a1f889949bc902d3575308cc7b0de30b4f6d27c7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "regex"
 version = "1.11.1"
@@ -1570,6 +1642,18 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "schemars"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4cd191f9397d57d581cddd31014772520aa448f65ef991055d7f61582c65165f"
+dependencies = [
+ "dyn-clone",
+ "ref-cast",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "scopeguard"
 version = "1.2.0"
@@ -1617,6 +1701,37 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_with"
+version = "3.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf65a400f8f66fb7b0552869ad70157166676db75ed8181f8104ea91cf9d0b42"
+dependencies = [
+ "base64",
+ "chrono",
+ "hex",
+ "indexmap 1.9.3",
+ "indexmap 2.9.0",
+ "schemars",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "serde_with_macros",
+ "time",
+]
+
+[[package]]
+name = "serde_with_macros"
+version = "3.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81679d9ed988d5e9a5e6531dc3f2c28efbd639cbd1dfb628df08edea6004da77"
+dependencies = [
+ "darling",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "serial2"
 version = "0.2.29"
@@ -1824,6 +1939,7 @@ dependencies = [
  "rustc-hash",
  "serde",
  "serde_json",
+ "serde_with",
  "signal-hook",
  "string_pipeline",
  "tempfile",
@@ -1900,6 +2016,37 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "time"
+version = "0.3.41"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a7619e19bc266e0f9c5e6686659d394bc57973859340060a69221e57dbc0c40"
+dependencies = [
+ "deranged",
+ "itoa",
+ "num-conv",
+ "powerfmt",
+ "serde",
+ "time-core",
+ "time-macros",
+]
+
+[[package]]
+name = "time-core"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c9e9a38711f559d9e3ce1cdb06dd7c5b8ea546bc90052da6d06bb76da74bb07c"
+
+[[package]]
+name = "time-macros"
+version = "0.2.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3526739392ec93fd8b359c8e98514cb3e8e021beb4e5f597b00a0221f8ed8a49"
+dependencies = [
+ "num-conv",
+ "time-core",
+]
+
 [[package]]
 name = "tinytemplate"
 version = "1.2.1"
@@ -1966,7 +2113,7 @@ version = "0.22.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "17b4795ff5edd201c7cd6dca065ae59972ce77d1b80fa0a84d94950ece7d1474"
 dependencies = [
- "indexmap",
+ "indexmap 2.9.0",
  "serde",
  "serde_spanned",
  "toml_datetime",

Cargo.toml

@@ -58,6 +58,7 @@ string_pipeline = "0.11.1"
 ureq = "3.0.11"
 serde_json = "1.0.140"
 colored = "3.0.0"
+serde_with = "3.13.0"
 
 
 # target specific dependencies

cable/unix/env.toml

@@ -12,3 +12,4 @@ command = "echo '{split:=:1..}'"
 [ui]
 layout = "portrait"
 preview_size = 20
+preview_header = "{split:=:0}"

television/channels/prototypes.rs

@@ -1,12 +1,14 @@
 use anyhow::Result;
 use std::fmt::{self, Display, Formatter};
+use std::hash::{Hash, Hasher};
 
 use crate::{
     config::KeyBindings,
     screen::layout::{InputPosition, Orientation},
 };
 use rustc_hash::FxHashMap;
-use serde::ser::SerializeSeq;
+use serde::{Deserialize, Serialize};
+use serde_with::{OneOrMany, serde_as};
 use string_pipeline::MultiTemplate;
 
 #[derive(Debug, Clone)]
@@ -53,13 +55,49 @@ impl Display for Template {
     }
 }
 
+impl PartialEq for Template {
+    fn eq(&self, other: &Self) -> bool {
+        self.raw() == other.raw()
+            && matches!(
+                (self, other),
+                (Template::StringPipeline(_), Template::StringPipeline(_))
+                    | (Template::Raw(_), Template::Raw(_))
+            )
+    }
+}
+
+impl Eq for Template {}
+
+impl Hash for Template {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.raw().hash(state);
+    }
+}
+
+impl Serialize for Template {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(self.raw())
+    }
+}
+
+impl<'de> Deserialize<'de> for Template {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let raw = String::deserialize(deserializer)?;
+        Template::parse(&raw).map_err(serde::de::Error::custom)
+    }
+}
+
+#[serde_as]
 #[derive(Debug, Clone, serde::Deserialize, serde::Serialize)]
 pub struct CommandSpec {
-    #[serde(
+    #[serde(rename = "command")]
-        rename = "command",
+    #[serde_as(as = "OneOrMany<_>")]
-        deserialize_with = "deserialize_commands",
-        serialize_with = "serialize_commands"
-    )]
     pub inner: Vec<Template>,
     #[serde(default)]
     pub interactive: bool,
@@ -67,13 +105,6 @@ pub struct CommandSpec {
     pub env: FxHashMap<String, String>,
 }
 
-#[derive(Debug, Clone, serde::Deserialize, serde::Serialize)]
-#[serde(untagged)]
-enum SerializedCommand {
-    Single(String),
-    Multiple(Vec<String>),
-}
-
 impl Display for CommandSpec {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         write!(
@@ -118,142 +149,6 @@ impl CommandSpec {
     }
 }
 
-fn serialize_command<S>(
-    command: &Template,
-    serializer: S,
-) -> Result<S::Ok, S::Error>
-where
-    S: serde::Serializer,
-{
-    serializer.serialize_str(command.raw())
-}
-
-#[allow(clippy::ref_option)]
-fn serialize_maybe_command<S>(
-    command: &Option<Template>,
-    serializer: S,
-) -> Result<S::Ok, S::Error>
-where
-    S: serde::Serializer,
-{
-    match command {
-        Some(cmd) => serialize_command(cmd, serializer),
-        None => serializer.serialize_none(),
-    }
-}
-
-#[allow(dead_code)]
-fn deserialize_command<'de, D>(deserializer: D) -> Result<Template, D::Error>
-where
-    D: serde::Deserializer<'de>,
-{
-    let raw: String = serde::Deserialize::deserialize(deserializer)?;
-    Template::parse(&raw).map_err(serde::de::Error::custom)
-}
-
-fn deserialize_maybe_command<'de, D>(
-    deserializer: D,
-) -> Result<Option<Template>, D::Error>
-where
-    D: serde::Deserializer<'de>,
-{
-    let raw: Option<String> = serde::Deserialize::deserialize(deserializer)?;
-    match raw {
-        Some(cmd) => Template::parse(&cmd)
-            .map(Some)
-            .map_err(serde::de::Error::custom),
-        None => Ok(None),
-    }
-}
-
-fn serialize_commands<S>(
-    commands: &[Template],
-    serializer: S,
-) -> Result<S::Ok, S::Error>
-where
-    S: serde::Serializer,
-{
-    if commands.len() == 1 {
-        let raw = commands[0].raw();
-        serializer.serialize_str(raw)
-    } else {
-        let raw: Vec<String> =
-            commands.iter().map(|c| c.raw().to_string()).collect();
-        let mut seq = serializer.serialize_seq(Some(raw.len()))?;
-        for item in raw {
-            seq.serialize_element(&item)?;
-        }
-        seq.end()
-    }
-}
-
-#[allow(clippy::ref_option, dead_code)]
-fn serialize_maybe_commands<S>(
-    commands: Option<&[Template]>,
-    serializer: S,
-) -> Result<S::Ok, S::Error>
-where
-    S: serde::Serializer,
-{
-    match commands {
-        Some(m) => serialize_commands(m, serializer),
-        None => serializer.serialize_none(),
-    }
-}
-
-fn deserialize_commands<'de, D>(
-    deserializer: D,
-) -> Result<Vec<Template>, D::Error>
-where
-    D: serde::Deserializer<'de>,
-{
-    let res = match serde::Deserialize::deserialize(deserializer)? {
-        SerializedCommand::Single(cmd) => {
-            Template::parse(&cmd).map(|m| vec![m])
-        }
-        SerializedCommand::Multiple(cmds) => cmds
-            .iter()
-            .map(|cmd| Template::parse(cmd))
-            .collect::<Result<Vec<_>, _>>(),
-    }
-    .map_err(serde::de::Error::custom);
-
-    if let Ok(ref cmds) = res {
-        if cmds.is_empty() {
-            return Err(serde::de::Error::custom(
-                "Command list cannot be empty",
-            ));
-        }
-    }
-
-    res
-}
-
-#[allow(dead_code)]
-fn deserialize_maybe_commands<'de, D>(
-    deserializer: D,
-) -> Result<Option<Vec<Template>>, D::Error>
-where
-    D: serde::Deserializer<'de>,
-{
-    let raw: Option<SerializedCommand> =
-        serde::Deserialize::deserialize(deserializer)?;
-    match raw {
-        Some(template) => {
-            let cmd = match template {
-                SerializedCommand::Single(cmd) => {
-                    Template::parse(&cmd).map(|m| vec![m])
-                }
-                SerializedCommand::Multiple(cmds) => {
-                    cmds.iter().map(|cmd| Template::parse(cmd)).collect()
-                }
-            };
-            cmd.map_err(serde::de::Error::custom).map(Some)
-        }
-        None => Ok(None),
-    }
-}
-
 #[derive(Debug, Clone, serde::Deserialize, serde::Serialize)]
 pub struct ChannelPrototype {
     pub metadata: Metadata,
@@ -342,17 +237,9 @@ pub struct Metadata {
 pub struct SourceSpec {
     #[serde(flatten)]
     pub command: CommandSpec,
-    #[serde(
+    #[serde(default)]
-        default,
-        deserialize_with = "deserialize_maybe_command",
-        serialize_with = "serialize_maybe_command"
-    )]
     pub display: Option<Template>,
-    #[serde(
+    #[serde(default)]
-        default,
-        deserialize_with = "deserialize_maybe_command",
-        serialize_with = "serialize_maybe_command"
-    )]
     pub output: Option<Template>,
 }
 
@@ -360,11 +247,7 @@ pub struct SourceSpec {
 pub struct PreviewSpec {
     #[serde(flatten)]
     pub command: CommandSpec,
-    #[serde(
+    #[serde(default)]
-        default,
-        deserialize_with = "deserialize_maybe_command",
-        serialize_with = "serialize_maybe_command"
-    )]
     pub offset: Option<Template>,
 }
 
@@ -397,12 +280,18 @@ pub struct UiSpec {
     #[serde(default)]
     pub show_preview_panel: Option<bool>,
     // `layout` is clearer for the user but collides with the overall `Layout` type.
-    #[serde(rename = "layout", default)]
+    #[serde(rename = "layout", alias = "orientation", default)]
     pub orientation: Option<Orientation>,
     #[serde(default)]
     pub input_bar_position: Option<InputPosition>,
     #[serde(default)]
     pub preview_size: Option<u16>,
+    #[serde(default)]
+    pub input_header: Option<Template>,
+    #[serde(default)]
+    pub preview_header: Option<Template>,
+    #[serde(default)]
+    pub preview_footer: Option<Template>,
 }
 
 pub const DEFAULT_PROTOTYPE_NAME: &str = "files";
@@ -432,6 +321,41 @@ mod tests {
         assert_eq!(command_spec.get_nth(3).raw(), "cmd1"); // wraps around
     }
 
+    #[test]
+    fn test_template_serialization() {
+        #[derive(Deserialize, Serialize, Debug, PartialEq)]
+        struct TestStruct {
+            template: Template,
+        }
+        let raw_1 = r#"template = "Hello, {}""#;
+        let raw_2 = r#"template = "Hello, World""#;
+        let raw_3 = r#"template = "docker images --format '{{.Repository}}:{{.Tag}} {{.ID}}'""#;
+
+        let test_1: TestStruct = from_str(raw_1).unwrap();
+        let test_2: TestStruct = from_str(raw_2).unwrap();
+        let test_3: TestStruct = from_str(raw_3).unwrap();
+
+        assert_eq!(
+            test_1.template,
+            Template::StringPipeline(
+                MultiTemplate::parse("Hello, {}").unwrap()
+            )
+        );
+        assert_eq!(
+            test_2.template,
+            Template::StringPipeline(
+                MultiTemplate::parse("Hello, World").unwrap()
+            )
+        );
+        assert_eq!(
+            test_3.template,
+            Template::Raw(
+                "docker images --format '{{.Repository}}:{{.Tag}} {{.ID}}'"
+                    .to_string()
+            )
+        );
+    }
+
     #[test]
     fn test_channel_prototype_deserialization() {
         let toml_data = r#"
@@ -445,13 +369,14 @@ mod tests {
         interactive = false
         env = {}
         display = "{split:/:-1}" # only show the last path segment ('/a/b/c' -> 'c')
-        ansi = false
         output = "{}"            # output the full path
+        unknown_field = "ignored" # should be ignored
 
         [preview]
         command = "bat -n --color=always {}"
         env = { "BAT_THEME" = "ansi" }
         interactive = false
+        offset = "3" # why not
 
         [ui]
         layout = "landscape"
@@ -459,6 +384,10 @@ mod tests {
         show_help_bar = false
         show_preview_panel = true
         input_bar_position = "bottom"
+        preview_size = 66
+        input_header = "Input: {}"
+        preview_header = "Preview: {}"
+        preview_footer = "Press 'q' to quit"
 
         [keybindings]
         quit = ["esc", "ctrl-c"]
@@ -478,19 +407,37 @@ mod tests {
             format!("{}", prototype.source.command.inner[0]),
             "fd -t f"
         );
+
         assert!(!prototype.source.command.interactive);
         assert_eq!(prototype.source.display.unwrap().raw(), "{split:/:-1}");
         assert_eq!(prototype.source.output.unwrap().raw(), "{}");
+
+        let preview = prototype.preview.as_ref().unwrap();
         assert_eq!(
-            format!("{}", prototype.preview.unwrap().command.inner[0]),
+            format!("{}", preview.command.inner[0]),
             "bat -n --color=always {}"
         );
+        assert!(!preview.command.interactive);
+        assert_eq!(
+            preview.command.env.get("BAT_THEME"),
+            Some(&"ansi".to_string())
+        );
+        assert_eq!(preview.offset.as_ref().unwrap().raw(), "3");
+
         let ui = prototype.ui.unwrap();
         assert_eq!(ui.orientation, Some(Orientation::Landscape));
         assert_eq!(ui.ui_scale, Some(100));
         assert!(!(ui.show_help_bar.unwrap()));
         assert!(ui.show_preview_panel.unwrap());
         assert_eq!(ui.input_bar_position, Some(InputPosition::Bottom));
+        assert_eq!(ui.preview_size, Some(66));
+        assert_eq!(ui.input_header.as_ref().unwrap().raw(), "Input: {}");
+        assert_eq!(ui.preview_header.as_ref().unwrap().raw(), "Preview: {}");
+        assert_eq!(
+            ui.preview_footer.as_ref().unwrap().raw(),
+            "Press 'q' to quit"
+        );
+
         let keybindings = prototype.keybindings.unwrap();
         assert_eq!(
             keybindings.0.get(&Action::Quit),
@@ -599,6 +546,7 @@ mod tests {
         [ui]
         layout = "landscape"
         ui_scale = 40
+        preview_footer = "Press 'q' to quit"
         "#;
 
         let prototype: ChannelPrototype = from_str(toml_data).unwrap();
@@ -623,5 +571,12 @@ mod tests {
         assert!(ui.show_help_bar.is_none());
         assert!(ui.show_preview_panel.is_none());
         assert!(ui.input_bar_position.is_none());
+        assert!(ui.preview_size.is_none());
+        assert!(ui.input_header.is_none());
+        assert!(ui.preview_header.is_none());
+        assert_eq!(
+            ui.preview_footer.as_ref().unwrap().raw(),
+            "Press 'q' to quit"
+        );
     }
 }

television/cli/args.rs

@@ -69,13 +69,35 @@ pub struct Cli {
     #[arg(short, long, value_name = "STRING", verbatim_doc_comment)]
     pub input: Option<String>,
 
-    /// Input fields header title
+    /// Input field header template.
     ///
-    /// This can be used to give the input field a custom title e.g. the current
+    /// The given value is parsed as a `MultiTemplate`. It is evaluated against
-    /// working directory.
+    /// the current channel name and the resulting text is shown as the input
-    /// The default value for the input header is the current channel.
+    /// field title. Defaults to the current channel name when omitted.
-    #[arg(long, value_name = "STRING", verbatim_doc_comment)]
+    #[arg(long = "input-header", value_name = "STRING", verbatim_doc_comment)]
-    pub custom_header: Option<String>,
+    pub input_header: Option<String>,
+
+    /// Preview header template
+    ///
+    /// The given value is parsed as a `MultiTemplate`. It is evaluated for every
+    /// entry and its result is displayed above the preview panel.
+    #[arg(
+        long = "preview-header",
+        value_name = "STRING",
+        verbatim_doc_comment
+    )]
+    pub preview_header: Option<String>,
+
+    /// Preview footer template
+    ///
+    /// The given value is parsed as a `MultiTemplate`. It is evaluated for every
+    /// entry and its result is displayed below the preview panel.
+    #[arg(
+        long = "preview-footer",
+        value_name = "STRING",
+        verbatim_doc_comment
+    )]
+    pub preview_footer: Option<String>,
 
     /// The working directory to start the application in.
     ///

television/cli/mod.rs

@@ -28,7 +28,9 @@ pub struct PostProcessedCli {
     pub tick_rate: Option<f64>,
     pub frame_rate: Option<f64>,
     pub input: Option<String>,
-    pub custom_header: Option<String>,
+    pub input_header: Option<String>,
+    pub preview_header: Option<String>,
+    pub preview_footer: Option<String>,
     pub command: Option<Command>,
     pub working_directory: Option<String>,
     pub autocomplete_prompt: Option<String>,
@@ -52,7 +54,9 @@ impl Default for PostProcessedCli {
             tick_rate: None,
             frame_rate: None,
             input: None,
-            custom_header: None,
+            input_header: None,
+            preview_header: None,
+            preview_footer: None,
             command: None,
             working_directory: None,
             autocomplete_prompt: None,
@@ -115,7 +119,9 @@ pub fn post_process(cli: Cli) -> PostProcessedCli {
         tick_rate: cli.tick_rate,
         frame_rate: cli.frame_rate,
         input: cli.input,
-        custom_header: cli.custom_header,
+        input_header: cli.input_header,
+        preview_header: cli.preview_header,
+        preview_footer: cli.preview_footer,
         command: cli.command,
         working_directory,
         autocomplete_prompt: cli.autocomplete_prompt,

television/config/mod.rs

@@ -242,6 +242,17 @@ impl Config {
         if let Some(preview_size) = &ui_spec.preview_size {
             self.ui.preview_size = *preview_size;
         }
+        if let Some(input_header) = &ui_spec.input_header {
+            self.ui.input_header = Some(input_header.clone());
+        }
+
+        if let Some(preview_header) = &ui_spec.preview_header {
+            self.ui.preview_header = Some(preview_header.clone());
+        }
+
+        if let Some(preview_footer) = &ui_spec.preview_footer {
+            self.ui.preview_footer = Some(preview_footer.clone());
+        }
     }
 }
 

television/config/ui.rs

@@ -1,3 +1,4 @@
+use crate::channels::prototypes::Template;
 use serde::{Deserialize, Serialize};
 
 use crate::screen::layout::{
@@ -23,9 +24,13 @@ pub struct UiConfig {
     pub orientation: Orientation,
     pub preview_title_position: Option<PreviewTitlePosition>,
     pub theme: String,
-    pub custom_header: Option<String>,
-
     pub preview_size: u16,
+    #[serde(default)]
+    pub input_header: Option<Template>,
+    #[serde(default)]
+    pub preview_header: Option<Template>,
+    #[serde(default)]
+    pub preview_footer: Option<Template>,
 }
 
 impl Default for UiConfig {
@@ -40,8 +45,10 @@ impl Default for UiConfig {
             orientation: Orientation::Landscape,
             preview_title_position: None,
             theme: String::from(DEFAULT_THEME),
-            custom_header: None,
             preview_size: DEFAULT_PREVIEW_SIZE,
+            input_header: None,
+            preview_header: None,
+            preview_footer: None,
         }
     }
 }

television/draw.rs

@@ -247,7 +247,7 @@ pub fn draw(ctx: &Ctx, f: &mut Frame<'_>, area: Rect) -> Result<Layout> {
         &ctx.tv_state.channel_state.current_channel_name,
         &ctx.tv_state.spinner,
         &ctx.colorscheme,
-        &ctx.config.ui.custom_header,
+        &ctx.config.ui.input_header,
         &ctx.config.ui.input_bar_position,
     )?;
 

television/main.rs

@@ -10,7 +10,7 @@ use television::cli::post_process;
 use television::gh::update_local_channels;
 use television::{
     cable::Cable, channels::prototypes::ChannelPrototype,
-    utils::clipboard::CLIPBOARD,
+    channels::prototypes::Template, utils::clipboard::CLIPBOARD,
 };
 use tracing::{debug, error, info};
 
@@ -81,8 +81,34 @@ async fn main() -> Result<()> {
         args.preview_size,
         config.application.tick_rate,
     );
-    let mut app =
+    let mut app = App::new(
-        App::new(channel_prototype, config, args.input, options, cable);
+        channel_prototype,
+        config,
+        args.input.clone(),
+        options,
+        cable,
+    );
+
+    // Apply CLI template overrides last (highest priority). This must run
+    // AFTER the channel-specific UI spec has been merged (inside
+    // `Television::new`) so that CLI flags win over both global and channel
+    // configuration.
+    if let Some(ref s) = args.input_header {
+        if let Ok(t) = Template::parse(s) {
+            app.television.config.ui.input_header = Some(t);
+        }
+    }
+    if let Some(ref s) = args.preview_header {
+        if let Ok(t) = Template::parse(s) {
+            app.television.config.ui.preview_header = Some(t);
+        }
+    }
+    if let Some(ref s) = args.preview_footer {
+        if let Ok(t) = Template::parse(s) {
+            app.television.config.ui.preview_footer = Some(t);
+        }
+    }
+
     stdout().flush()?;
     debug!("Running application...");
     let output = app.run(stdout().is_terminal(), false).await?;
@@ -128,9 +154,6 @@ fn apply_cli_overrides(args: &PostProcessedCli, config: &mut Config) {
         config.keybindings =
             merge_keybindings(config.keybindings.clone(), keybindings);
     }
-    if let Some(header) = &args.custom_header {
-        config.ui.custom_header = Some(header.to_string());
-    }
     config.ui.ui_scale = args.ui_scale;
 }
 

television/previewer/mod.rs

@@ -101,6 +101,7 @@ pub struct Preview {
     pub content: String,
     pub icon: Option<FileIcon>,
     pub total_lines: u16,
+    pub footer: String,
 }
 
 const DEFAULT_PREVIEW_TITLE: &str = "Select an entry to preview";
@@ -112,6 +113,7 @@ impl Default for Preview {
             content: String::new(),
             icon: None,
             total_lines: 1,
+            footer: String::new(),
         }
     }
 }
@@ -122,12 +124,14 @@ impl Preview {
         content: String,
         icon: Option<FileIcon>,
         total_lines: u16,
+        footer: String,
     ) -> Self {
         Self {
             title: title.to_string(),
             content,
             icon,
             total_lines,
+            footer,
         }
     }
 }
@@ -243,6 +247,7 @@ pub fn try_preview(
                 content.to_string(),
                 None,
                 u16::try_from(content.lines().count()).unwrap_or(u16::MAX),
+                String::new(),
             )
         } else {
             let (content, _) = replace_non_printable(
@@ -256,6 +261,7 @@ pub fn try_preview(
                 content.to_string(),
                 None,
                 u16::try_from(content.lines().count()).unwrap_or(u16::MAX),
+                String::new(),
             )
         }
     };

television/previewer/state.rs

@@ -51,7 +51,11 @@ impl PreviewState {
         scroll: u16,
         target_line: Option<u16>,
     ) {
-        if self.preview.title != preview.title || self.scroll != scroll {
+        if self.preview.title != preview.title
+            || self.preview.content != preview.content
+            || self.preview.footer != preview.footer
+            || self.scroll != scroll
+        {
             self.preview = preview;
             self.scroll = scroll;
             self.target_line = target_line;
@@ -91,6 +95,7 @@ impl PreviewState {
                 cropped_content,
                 self.preview.icon,
                 self.preview.total_lines,
+                self.preview.footer.clone(),
             ),
             num_skipped_lines,
             target_line,

television/screen/input.rs

@@ -1,3 +1,4 @@
+use crate::channels::prototypes::Template;
 use crate::utils::input::Input;
 use anyhow::Result;
 use ratatui::{
@@ -28,10 +29,13 @@ pub fn draw_input_box(
     channel_name: &str,
     spinner: &Spinner,
     colorscheme: &Colorscheme,
-    custom_header: &Option<String>,
+    input_header: &Option<Template>,
     input_bar_position: &InputPosition,
 ) -> Result<()> {
-    let header = custom_header.as_deref().unwrap_or(channel_name);
+    let header = input_header
+        .as_ref()
+        .and_then(|tpl| tpl.format(channel_name).ok())
+        .unwrap_or_else(|| channel_name.to_string());
     let input_block = Block::default()
         .borders(Borders::ALL)
         .border_type(BorderType::Rounded)
@@ -41,7 +45,7 @@ pub fn draw_input_box(
             InputPosition::Bottom => Position::Bottom,
         })
         .title(
-            Line::from(String::from(" ") + header + " ")
+            Line::from(format!(" {} ", header))
                 .style(Style::default().fg(colorscheme.mode.channel).bold())
                 .centered(),
         )

television/screen/preview.rs

@@ -29,6 +29,7 @@ pub fn draw_preview_content_block(
         colorscheme,
         preview_state.preview.icon,
         &preview_state.preview.title,
+        &preview_state.preview.footer,
         use_nerd_font_icons,
     )?;
     // render the preview content
@@ -138,6 +139,7 @@ fn draw_content_outer_block(
     colorscheme: &Colorscheme,
     icon: Option<FileIcon>,
     title: &str,
+    footer: &str,
     use_nerd_font_icons: bool,
 ) -> Result<Rect> {
     let mut preview_title_spans = vec![Span::from(" ")];
@@ -153,7 +155,7 @@ fn draw_content_outer_block(
             Style::default().fg(Color::from_str(icon.color)?),
         ));
     }
-    // preview title
+    // preview header
     preview_title_spans.push(Span::styled(
         shrink_with_ellipsis(
             &replace_non_printable(
@@ -167,13 +169,26 @@ fn draw_content_outer_block(
     ));
     preview_title_spans.push(Span::from(" "));
 
-    // build the preview block
+    let mut block = Block::default();
-    let preview_outer_block = Block::default()
+    block = block.title_top(
-        .title_top(
+        Line::from(preview_title_spans)
-            Line::from(preview_title_spans)
+            .alignment(Alignment::Center)
-                .alignment(Alignment::Center)
+            .style(Style::default().fg(colorscheme.preview.title_fg)),
-                .style(Style::default().fg(colorscheme.preview.title_fg)),
+    );
-        )
+
+    // preview footer
+    if !footer.is_empty() {
+        let footer_line = Line::from(vec![
+            Span::from(" "),
+            Span::from(footer),
+            Span::from(" "),
+        ])
+        .alignment(Alignment::Center)
+        .style(Style::default().fg(colorscheme.preview.title_fg));
+        block = block.title_bottom(footer_line);
+    }
+
+    let preview_outer_block = block
         .borders(Borders::ALL)
         .border_type(BorderType::Rounded)
         .border_style(Style::default().fg(colorscheme.general.border_fg))

television/television.rs

@@ -184,6 +184,21 @@ impl Television {
         // ui
         if let Some(ui_spec) = &channel_prototype.ui {
             config.apply_prototype_ui_spec(ui_spec);
+            if config.ui.input_header.is_none() {
+                if let Some(header_tpl) = &ui_spec.input_header {
+                    config.ui.input_header = Some(header_tpl.clone());
+                }
+            }
+            if config.ui.preview_header.is_none() {
+                if let Some(ph) = &ui_spec.preview_header {
+                    config.ui.preview_header = Some(ph.clone());
+                }
+            }
+            if config.ui.preview_footer.is_none() {
+                if let Some(pf) = &ui_spec.preview_footer {
+                    config.ui.preview_footer = Some(pf.clone());
+                }
+            }
         }
         config
     }
@@ -491,7 +506,21 @@ impl Television {
             }
             // available previews
             let entry = selected_entry.as_ref().unwrap();
-            if let Ok(preview) = receiver.try_recv() {
+            if let Ok(mut preview) = receiver.try_recv() {
+                if let Some(tpl) = &self.config.ui.preview_header {
+                    preview.title = tpl
+                        .format(&entry.raw)
+                        .unwrap_or_else(|_| entry.raw.clone());
+                } else {
+                    preview.title.clone_from(&entry.raw);
+                }
+
+                if let Some(ftpl) = &self.config.ui.preview_footer {
+                    preview.footer = ftpl
+                        .format(&entry.raw)
+                        .unwrap_or_else(|_| String::new());
+                }
+
                 let scroll = entry
                     .line_number
                     .unwrap_or(0)

tests/e2e.rs

@@ -211,6 +211,34 @@ fn tv_remote_control() {
     assert_exit_ok(&mut child, DEFAULT_TIMEOUT);
 }
 
+#[test]
+fn tv_custom_input_header_and_preview_size() {
+    let pty_system = native_pty_system();
+    // Create a new pty
+    let pair = pty_system.openpty(DEFAULT_PTY_SIZE).unwrap();
+
+    // Spawn a tv process in the pty
+    let mut cmd = tv_command("files");
+    cmd.args(["--input-header", "bagels"]);
+    let mut child = pair.slave.spawn_command(cmd).unwrap();
+    sleep(Duration::from_millis(200));
+
+    // Read the output from the pty
+    let mut buf = [0; 5096];
+    let mut reader = pair.master.try_clone_reader().unwrap();
+    let _ = reader.read(&mut buf).unwrap();
+    let output = String::from_utf8_lossy(&buf);
+
+    assert!(output.contains("bagels"));
+
+    // Send Ctrl-C to the process
+    let mut writer = pair.master.take_writer().unwrap();
+    writeln!(writer, "\x03").unwrap(); // Ctrl-C
+    sleep(Duration::from_millis(200));
+
+    assert_exit_ok(&mut child, DEFAULT_TIMEOUT);
+}
+
 macro_rules! test_channel {
     ($($name:ident: $channel_name:expr,)*) => {
     $(