From bd1e965f936c9fe652bd940c1f12e3327f06a222 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Sat, 10 Nov 2018 00:50:24 -0500
Subject: add sql subcommand for raw queries

this was more painful than i think it should have been
---
 src/cli.rs     | 26 +++++++++++++++++++-
 src/cmd/mod.rs |  1 +
 src/cmd/sql.rs | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/db.rs      | 26 ++++++++++++++++++++
 src/main.rs    |  1 +
 5 files changed, 130 insertions(+), 1 deletion(-)
 create mode 100644 src/cmd/sql.rs

diff --git a/src/cli.rs b/src/cli.rs
index 1976d93..c2cae24 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -3,7 +3,11 @@ const _DUMMY_DEPENDENCY: &'static str = include_str!("../Cargo.toml");
 pub enum Command {
     Sync {
         username: String,
-    }
+    },
+    SQL {
+        query: String,
+        tsv: bool,
+    },
 }
 
 pub fn get_options() -> failure::Fallible<Command> {
@@ -17,6 +21,20 @@ pub fn get_options() -> failure::Fallible<Command> {
                         .help("last.fm username to fetch tracks for")
                 )
         )
+        .subcommand(
+            clap::SubCommand::with_name("sql")
+                .about("Run a query against the local database")
+                .arg(
+                    clap::Arg::with_name("query")
+                        .required(true)
+                        .help("query to run")
+                )
+                .arg(
+                    clap::Arg::with_name("tsv")
+                        .long("tsv")
+                        .help("format output as tsv")
+                )
+        )
         .get_matches();
 
     let command = match matches.subcommand() {
@@ -25,6 +43,12 @@ pub fn get_options() -> failure::Fallible<Command> {
                 username: matches.value_of("username").unwrap().to_string(),
             }
         },
+        ("sql", Some(matches)) => {
+            Command::SQL {
+                query: matches.value_of("query").unwrap().to_string(),
+                tsv: matches.is_present("tsv"),
+            }
+        },
         (name, Some(_)) => bail!("unknown subcommand: {}", name),
         (_, None) => bail!("no subcommand given"),
     };
diff --git a/src/cmd/mod.rs b/src/cmd/mod.rs
index d086d5b..a25e955 100644
--- a/src/cmd/mod.rs
+++ b/src/cmd/mod.rs
@@ -1 +1,2 @@
+pub mod sql;
 pub mod sync;
diff --git a/src/cmd/sql.rs b/src/cmd/sql.rs
new file mode 100644
index 0000000..ae398b5
--- /dev/null
+++ b/src/cmd/sql.rs
@@ -0,0 +1,77 @@
+use db;
+use paths;
+
+pub fn run(query: &str, tsv: bool) -> failure::Fallible<()> {
+    let db = db::DB::new(&paths::db_path()?)?;
+
+    let rows_cell = std::cell::Cell::new(Some(vec![]));
+    let cols = db.query(query, |row| {
+        let display_row: Vec<String> = (0..row.column_count())
+            .map(|i| row.get_raw(i))
+            .map(|v| format_value(&v))
+            .collect();
+        let mut rows = rows_cell.replace(None).unwrap();
+        rows.push(display_row);
+        rows_cell.replace(Some(rows));
+    })?;
+
+    let rows = rows_cell.into_inner().unwrap();
+
+    if tsv {
+        print_tsv(&rows);
+    }
+    else {
+        print_table(&cols, &rows);
+    }
+
+    Ok(())
+}
+
+fn print_table(cols: &[String], rows: &[Vec<String>]) {
+    let widths = column_widths(&cols, &rows);
+
+    print_row(&widths, &cols);
+    let border: Vec<String> = widths.iter().map(|l| "-".repeat(*l)).collect();
+    println!("{}", &border.join("-+-"));
+
+    for row in rows {
+        print_row(&widths, &row);
+    }
+}
+
+fn print_tsv(rows: &[Vec<String>]) {
+    for row in rows {
+        println!("{}", row.join("\t"));
+    }
+}
+
+fn format_value(v: &rusqlite::types::ValueRef) -> String {
+    match v {
+        rusqlite::types::ValueRef::Null => "null".to_string(),
+        rusqlite::types::ValueRef::Integer(i) => format!("{}", i),
+        rusqlite::types::ValueRef::Real(f) => format!("{}", f),
+        rusqlite::types::ValueRef::Text(s) => format!("{}", s),
+        rusqlite::types::ValueRef::Blob(b) => format!("{:?}", b),
+    }
+}
+
+fn column_widths(cols: &[String], rows: &[Vec<String>]) -> Vec<usize> {
+    let mut max_widths: Vec<usize> = cols.iter().map(|s| s.len()).collect();
+    for row in rows {
+        for (i, col) in row.iter().enumerate() {
+            if col.len() > max_widths[i] {
+                max_widths[i] = col.len();
+            }
+        }
+    }
+    max_widths
+}
+
+fn print_row(widths: &[usize], row: &[String]) {
+    let fixed_width_row: Vec<String> = row
+        .iter()
+        .zip(widths.iter())
+        .map(|(s, width)| format!("{:width$}", s, width=width))
+        .collect();
+    println!("{}", &fixed_width_row.join(" | "));
+}
diff --git a/src/db.rs b/src/db.rs
index 056886e..97522d9 100644
--- a/src/db.rs
+++ b/src/db.rs
@@ -90,4 +90,30 @@ impl DB {
         }
         Ok(())
     }
+
+    pub fn query<F: Fn(&rusqlite::Row)>(
+        &self,
+        query: &str,
+        f: F
+    ) -> failure::Fallible<Vec<String>> {
+        let mut sth = self.conn.prepare(query)?;
+
+        let cols = sth.column_names()
+            .iter()
+            .map(|s| s.to_string())
+            .collect();
+
+        let rows = sth.query_and_then(
+            rusqlite::NO_PARAMS,
+            |row| { f(row); Ok(()) },
+        )?;
+        // this call to collect() forces it to actually consume the iterator
+        // (and therefore call the callbacks). what i really want here is for
+        // there to be a query_for_each or something like that, but the weird
+        // way lifetimes work for rows makes it difficult to emulate this any
+        // other way
+        let errs: failure::Fallible<Vec<()>> = rows.collect();
+
+        errs.map(|_| cols)
+    }
 }
diff --git a/src/main.rs b/src/main.rs
index 4638adf..b43f310 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,6 +22,7 @@ fn run() -> failure::Fallible<()> {
     let command = cli::get_options()?;
     match command {
         cli::Command::Sync { username } => cmd::sync::run(&username),
+        cli::Command::SQL { query, tsv } => cmd::sql::run(&query, tsv),
     }
 }
 
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