aboutsummaryrefslogtreecommitdiff
path: root/src/main.rs
blob: f34413a9d21e89d94bea8ac078f9690799075b0b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
#![feature(iterator_try_collect)]

use clap::Parser;
use priority_queue::PriorityQueue;
use std::cmp::Ordering;
use std::collections::HashMap;
use std::path::PathBuf;

use embedders::*;

mod embedders;

#[derive(Debug, Clone, Copy, clap::ValueEnum)]
enum Embedder {
    Brightness,
    Hue,
}

#[derive(Debug, Parser)]
struct Args {
    #[arg(short, long, default_value = "hue")]
    embedder: Embedder,

    images: Vec<PathBuf>,
}

//#[derive(Debug)]
//struct Config {
//    base_dir: xdg::BaseDirectories,
//}
//
//fn get_config() -> Result<Config, String> {
//    let dirs = xdg::BaseDirectories::with_prefix("embeddings-sort")
//        .map_err(|_| "oh no")?;
//
//    Ok(Config{base_dir: dirs})
//}

fn process_embedder<E>(mut e: E, args: Args) -> Result<Vec<PathBuf>, String>
    where E: EmbedderT
{
    // wrapper struct to
    // - reverse the ordering
    // - implement Ord, even though the type is backed by an f64
    #[repr(transparent)]
    #[derive(Debug, PartialEq)]
    struct DownOrd (f64);
    impl Eq for DownOrd {}
    impl PartialOrd for DownOrd {
        fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
            Some(self.cmp(other))
        }
    }
    impl Ord for DownOrd {
        fn cmp(&self, other: &Self) -> Ordering {
            self.0.partial_cmp(&other.0).unwrap().reverse()
        }
    }

    let num_ims = args.images.len();
    if num_ims == 0 {
        return Ok(Vec::new());
    }

    let embeds: Vec<_> = e
        .embed(&args.images)?
        .into_iter()
        .collect();

    let mut possible_edges =
        PriorityQueue::with_capacity((num_ims * num_ims - num_ims) / 2);
    let mut mst = HashMap::with_capacity(num_ims);

    // here, we start at 0.
    // we might get a better result in the end if we started with a vertex next
    // to the lowest-cost edge, but we don't know which one that is (though we
    // could compute that without changing our asymptotic complexity)
    mst.insert(0, Vec::new());
    for i in 1..num_ims {
        possible_edges.push((0, i), DownOrd(embeds[0].dist(&embeds[i])));
    }

    // prims algorithm or something like that
    while mst.len() < num_ims {
        // find the edge with the least cost that connects us to a new vertex
        let (new, old) = loop {
            let ((a, b), _) = possible_edges.pop().unwrap();
            if !mst.contains_key(&a) {
                break (a, b);
            }
            else if !mst.contains_key(&b) {
                break (b, a);
            }
        };
        mst.insert(new, Vec::new());

        // insert all the new edges we could take
        mst.entry(old).and_modify(|v|v.push(new));
        for i in 0..num_ims {
            // don't consider edges taking us to nodes we already visited
            if mst.contains_key(&i) {
                continue;
            }

            possible_edges.push((new, i), DownOrd(embeds[new].dist(&embeds[i])));
        }
    }

    // find TSP approximation via DFS through the MST
    fn dfs(cur: usize, t: &HashMap<usize, Vec<usize>>, into: &mut Vec<usize>) {
        into.push(cur);
        t.get(&cur).unwrap().iter().for_each(|c| dfs(*c, t, into));
    }
    let mut tsp_path = Vec::with_capacity(num_ims);
    dfs(0, &mst, &mut tsp_path);

    Ok(tsp_path.iter().map(|i| args.images[*i].clone()).collect())
}

fn main() -> Result<(), String> {
    //let cfg = get_config()?;
    let args = Args::parse();

    let tsp_path = match args.embedder {
        Embedder::Brightness => process_embedder(BrightnessEmbedder, args),
        Embedder::Hue => process_embedder(HueEmbedder, args),
    }?;

    for p in tsp_path {
        println!("{:?}", p);
    }

    Ok(())
}