From 1a6f13e271e2cbad51b64acf6cf5e3b732a05d9f Mon Sep 17 00:00:00 2001
From: Colin <colin@uninsane.org>
Date: Tue, 15 Jun 2021 00:15:04 -0700
Subject: [PATCH] Add an (untested) way to persist measurements to disk

---
 Cargo.toml    |  1 +
 src/meas.rs   |  9 ++++++
 src/render.rs | 77 ++++++++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 472d3ab..19671da 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,7 @@ edition = "2018"
 bincode = "1.3.1"
 common_macros = "0.1"
 crossterm = "0.18"
+csv = "1.1"
 decorum = "0.3"
 dyn-clone = "1.0"
 enum_dispatch = "0.3"
diff --git a/src/meas.rs b/src/meas.rs
index 815846b..498bbe9 100644
--- a/src/meas.rs
+++ b/src/meas.rs
@@ -15,6 +15,15 @@ pub trait AbstractMeasurement: Send + Sync + DynClone {
 }
 dyn_clone::clone_trait_object!(AbstractMeasurement);
 
+pub fn eval_multiple_kv(state: &dyn GenericSim, meas: &[Box<dyn AbstractMeasurement>]) -> BTreeMap<String, String> {
+    let mut r = BTreeMap::new();
+    for m in meas {
+        let mut other = m.key_value(state);
+        r.append(&mut other);
+    }
+    r
+}
+
 #[derive(Clone, Serialize, Deserialize)]
 pub struct Time;
 
diff --git a/src/render.rs b/src/render.rs
index 353c453..2786d82 100644
--- a/src/render.rs
+++ b/src/render.rs
@@ -1,7 +1,7 @@
 use crate::geom::{Index, Meters, Vec2, Vec3, Vec3u};
 use crate::real::ToFloat as _;
 use crate::sim::{GenericSim, Sample, StaticSim};
-use crate::meas::AbstractMeasurement;
+use crate::meas::{self, AbstractMeasurement};
 use crossterm::{cursor, QueueableCommand as _};
 use crossterm::style::{style, Color, PrintStyledContent};
 use font8x8::{BASIC_FONTS, GREEK_FONTS, UnicodeFonts as _};
@@ -12,9 +12,9 @@ use image::{RgbImage, Rgb};
 use imageproc::{pixelops, drawing};
 use rayon::prelude::*;
 use serde::{Serialize, Deserialize};
-use std::fs::File;
-use std::io::{BufReader, BufWriter, Write as _};
-use std::path::PathBuf;
+use std::fs::{File, OpenOptions};
+use std::io::{BufReader, BufWriter, Seek as _, SeekFrom, Write as _};
+use std::path::{Path, PathBuf};
 use std::sync::{Mutex, RwLock};
 use y4m;
 
@@ -718,3 +718,72 @@ impl<S: GenericSim + Serialize> Renderer<S> for SerializerRenderer {
         }
     }
 }
+
+enum CsvState {
+    Reading(csv::Reader<BufReader<File>>),
+    Writing(csv::Writer<BufWriter<File>>),
+}
+
+pub struct CsvRenderer {
+    state: Mutex<Option<CsvState>>,
+}
+
+impl CsvRenderer {
+    pub fn new<P: AsRef<Path>>(path: P) -> Self {
+        let f = OpenOptions::new().read(true).write(true).create(true).open(path).unwrap();
+        let reader = csv::Reader::from_reader(BufReader::new(f));
+        Self {
+            state: Mutex::new(Some(CsvState::Reading(reader))),
+        }
+    }
+}
+
+impl<S: GenericSim> Renderer<S> for CsvRenderer {
+    fn render_z_slice(&self, state: &S, z: u32, measurements: &[Box<dyn AbstractMeasurement>], config: RenderConfig) {
+        default_render_z_slice(self, state, z, measurements, config)
+    }
+    fn render(&self, state: &S, measurements: &[Box<dyn AbstractMeasurement>], _config: RenderConfig) {
+        let row = meas::eval_multiple_kv(state, measurements);
+        let step = state.step_no();
+        let mut lock = self.state.lock().unwrap();
+        let mut writer = match lock.take().unwrap() {
+            CsvState::Reading(mut reader) => {
+                let headers = reader.headers().unwrap();
+                let has_header = headers.get(0) == Some("step");
+                if has_header {
+                    // read until we get a row whose step is >= this one
+                    let mut seek_pos = None;
+                    for record in reader.records() {
+                        let record = record.unwrap();
+                        if let Some(step_str) = record.get(0) {
+                            if let Ok(step_num) = step_str.parse::<u64>() {
+                                if step_num >= step {
+                                    // truncate csv here
+                                    seek_pos = record.position().map(|p| p.byte());
+                                    break;
+                                }
+                            }
+                        }
+                    }
+                    let mut file = reader.into_inner().into_inner();
+                    if let Some(pos) = seek_pos {
+                        file.seek(SeekFrom::Start(pos)).unwrap();
+                        file.set_len(pos).unwrap();
+                    }
+                    csv::Writer::from_writer(BufWriter::new(file))
+                } else { // no header
+                    let mut file = reader.into_inner().into_inner();
+                    file.seek(SeekFrom::Start(0)).unwrap();
+                    file.set_len(0).unwrap();
+                    let mut writer = csv::Writer::from_writer(BufWriter::new(file));
+                    // write the header
+                    writer.write_record(row.keys()).unwrap();
+                    writer
+                }
+            },
+            CsvState::Writing(writer) => writer,
+        };
+        writer.write_record(row.values()).unwrap();
+        *lock = Some(CsvState::Writing(writer));
+    }
+}