Add option to export plain text room logs

src/export.rs

@@ -0,0 +1,72 @@
+//! Export logs from the vault to plain text files.
+
+use std::fs::File;
+use std::io::{BufWriter, Write};
+use std::path::Path;
+
+use unicode_width::UnicodeWidthStr;
+
+use crate::euph::api::Snowflake;
+use crate::store::{MsgStore, Tree};
+use crate::vault::{EuphMsg, Vault};
+
+const TIME_FORMAT: &str = "%F %T";
+const TIME_EMPTY: &str = "                   ";
+
+pub async fn export(vault: &Vault, room: String, file: &Path) -> anyhow::Result<()> {
+    let mut file = BufWriter::new(File::create(file)?);
+    let vault = vault.euph(room);
+
+    let mut tree_id = vault.first_tree().await;
+    while let Some(some_tree_id) = tree_id {
+        let tree = vault.tree(&some_tree_id).await;
+        write_tree(&mut file, &tree, some_tree_id, 0)?;
+        tree_id = vault.next_tree(&some_tree_id).await;
+    }
+
+    Ok(())
+}
+
+fn write_tree(
+    file: &mut BufWriter<File>,
+    tree: &Tree<EuphMsg>,
+    id: Snowflake,
+    indent: usize,
+) -> anyhow::Result<()> {
+    let indent_string = "| ".repeat(indent);
+
+    if let Some(msg) = tree.msg(&id) {
+        write_msg(file, &indent_string, msg)?;
+    } else {
+        write_placeholder(file, &indent_string)?;
+    }
+
+    if let Some(children) = tree.children(&id) {
+        for child in children {
+            write_tree(file, tree, *child, indent + 1)?;
+        }
+    }
+
+    Ok(())
+}
+
+fn write_msg(file: &mut BufWriter<File>, indent_string: &str, msg: &EuphMsg) -> anyhow::Result<()> {
+    let nick = &msg.nick;
+    let nick_empty = " ".repeat(nick.width());
+
+    for (i, line) in msg.content.lines().enumerate() {
+        if i == 0 {
+            let time = msg.time.0.format(TIME_FORMAT);
+            writeln!(file, "{time} {indent_string}[{nick}] {line}")?;
+        } else {
+            writeln!(file, "{TIME_EMPTY} {indent_string} {nick_empty}  {line}")?;
+        }
+    }
+
+    Ok(())
+}
+
+fn write_placeholder(file: &mut BufWriter<File>, indent_string: &str) -> anyhow::Result<()> {
+    writeln!(file, "{TIME_EMPTY} {indent_string}...")?;
+    Ok(())
+}