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

use mongodb_schema_describer::{CollectionId, IndexId, IndexType, MongoSchema};

#[derive(Debug)]
pub(crate) struct MongoDbMigration {
    pub(crate) previous: Box<MongoSchema>,
    pub(crate) next: Box<MongoSchema>,
    pub(crate) steps: Vec<MongoDbMigrationStep>,
}

impl MongoDbMigration {
    pub(crate) fn summary(&self) -> String {
        if self.steps.is_empty() {
            return "No difference detected.".to_owned();
        }

        let mut out = String::with_capacity(self.steps.len() * 10);

        for step in &self.steps {
            match step {
                MongoDbMigrationStep::CreateCollection(collection_id) => {
                    out.push_str("[+] Collection `");
                    out.push_str(self.next.walk_collection(*collection_id).name());
                    out.push_str("`\n");
                }
                MongoDbMigrationStep::CreateIndex(index_id) => {
                    let index = self.next.walk_index(*index_id);
                    out.push_str("[+] ");
                    match index.r#type() {
                        IndexType::Normal => out.push_str("Index `"),
                        IndexType::Unique => out.push_str("Unique index `"),
                        IndexType::Fulltext => out.push_str("Fulltext index `"),
                    }
                    out.push_str(index.name());
                    out.push_str("` on ({");

                    let fields = index.fields().map(ToString::to_string).collect::<Vec<_>>().join(",");

                    out.push_str(&fields);
                    out.push_str("})\n");
                }
                MongoDbMigrationStep::DropIndex(index_id) => {
                    let index = self.previous.walk_index(*index_id);
                    out.push_str("[-] ");
                    out.push_str(if index.is_unique() { "Unique index `" } else { "Index `" });
                    out.push_str(index.name());
                    out.push_str("`\n");
                }
            }
        }

        out
    }
}

/// The internal representation of a mongodb migration. The order of variants matters, it is used
/// for sorting and determines the order in which steps will be applied.
#[derive(Debug, PartialOrd, Ord, PartialEq, Eq)]
pub enum MongoDbMigrationStep {
    CreateCollection(CollectionId),
    DropIndex(IndexId),
    CreateIndex(IndexId),
}