1 files changed, 151 insertions, 0 deletions
diff --git a/src/env.rs b/src/env.rs
new file mode 100644
index 0000000..72a69d1
--- /dev/null
+++ b/src/env.rs
@@ -0,0 +1,151 @@
+use crate::prelude::*;
+
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
+pub enum Env {
+    V0(V0),
+}
+
+#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
+pub struct V0 {
+    pwd: std::path::PathBuf,
+    vars: std::collections::HashMap<std::ffi::OsString, std::ffi::OsString>,
+}
+
+const __NBSH_IDX: &str = "__NBSH_IDX";
+const __NBSH_LATEST_STATUS: &str = "__NBSH_LATEST_STATUS";
+const __NBSH_PREV_PWD: &str = "__NBSH_PREV_PWD";
+
+impl Env {
+    pub fn new() -> Result<Self> {
+        let pwd = std::env::current_dir()?;
+        Ok(Self::V0(V0 {
+            pwd: pwd.clone(),
+            vars: std::env::vars_os()
+                .chain(Self::defaults(pwd).into_iter())
+                .collect(),
+        }))
+    }
+
+    pub fn new_from_env() -> Result<Self> {
+        let pwd = std::env::current_dir()?;
+        Ok(Self::V0(V0 {
+            pwd: pwd.clone(),
+            vars: Self::defaults(pwd)
+                .into_iter()
+                .chain(std::env::vars_os())
+                .collect(),
+        }))
+    }
+
+    pub fn pwd(&self) -> &std::path::Path {
+        match self {
+            Self::V0(env) => &env.pwd,
+        }
+    }
+
+    pub fn var(&self, k: &str) -> Option<String> {
+        match self {
+            Self::V0(env) => self.special_var(k).or_else(|| {
+                env.vars
+                    .get(std::ffi::OsStr::new(k))
+                    .map(|v| v.to_str().unwrap().to_string())
+            }),
+        }
+    }
+
+    pub fn set_var<
+        K: Into<std::ffi::OsString>,
+        V: Into<std::ffi::OsString>,
+    >(
+        &mut self,
+        k: K,
+        v: V,
+    ) {
+        match self {
+            Self::V0(env) => {
+                env.vars.insert(k.into(), v.into());
+            }
+        }
+    }
+
+    pub fn idx(&self) -> usize {
+        self.var(__NBSH_IDX).unwrap().parse().unwrap()
+    }
+
+    pub fn set_idx(&mut self, idx: usize) {
+        self.set_var(__NBSH_IDX, format!("{}", idx));
+    }
+
+    pub fn latest_status(&self) -> std::process::ExitStatus {
+        std::process::ExitStatus::from_raw(
+            self.var(__NBSH_LATEST_STATUS).unwrap().parse().unwrap(),
+        )
+    }
+
+    pub fn set_status(&mut self, status: std::process::ExitStatus) {
+        self.set_var(
+            __NBSH_LATEST_STATUS,
+            format!(
+                "{}",
+                (status.code().unwrap_or(0) << 8)
+                    | status.signal().unwrap_or(0)
+            ),
+        );
+    }
+
+    pub fn prev_pwd(&self) -> std::path::PathBuf {
+        std::path::PathBuf::from(self.var(__NBSH_PREV_PWD).unwrap())
+    }
+
+    pub fn set_prev_pwd(&mut self, prev_pwd: std::path::PathBuf) {
+        self.set_var(__NBSH_PREV_PWD, prev_pwd);
+    }
+
+    pub fn apply(&self, cmd: &mut pty_process::Command) {
+        match self {
+            Self::V0(env) => {
+                cmd.current_dir(&env.pwd);
+                cmd.env_clear();
+                cmd.envs(env.vars.iter());
+            }
+        }
+    }
+
+    pub fn update(&mut self) -> Result<()> {
+        let idx = self.idx();
+        let status = self.latest_status();
+        let prev_pwd = self.prev_pwd();
+        *self = Self::new()?;
+        self.set_idx(idx);
+        self.set_status(status);
+        self.set_prev_pwd(prev_pwd);
+        Ok(())
+    }
+
+    fn special_var(&self, k: &str) -> Option<String> {
+        Some(match k {
+            "$" => crate::info::pid(),
+            "?" => {
+                let status = self.latest_status();
+                status
+                    .signal()
+                    .map_or_else(
+                        || status.code().unwrap(),
+                        |signal| signal + 128,
+                    )
+                    .to_string()
+            }
+            _ => return None,
+        })
+    }
+
+    fn defaults(
+        pwd: std::path::PathBuf,
+    ) -> [(std::ffi::OsString, std::ffi::OsString); 3] {
+        [
+            (__NBSH_IDX.into(), "0".into()),
+            (__NBSH_LATEST_STATUS.into(), "0".into()),
+            (__NBSH_PREV_PWD.into(), pwd.into()),
+        ]
+    }
+}