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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
use std::{any::Any, sync::Arc};

use async_trait::async_trait;
use datafusion::logical_expr::{TableSource, TableType};
use datafusion::{
    arrow::datatypes::SchemaRef, catalog::SchemaProvider, datasource::TableProvider, error::Result,
};
use futures::future::join_all;

use crate::{
    sql::SQLFederationProvider, FederatedTableProviderAdaptor, FederatedTableSource,
    FederationProvider,
};

pub struct SQLSchemaProvider {
    // provider: Arc<SQLFederationProvider>,
    tables: Vec<Arc<SQLTableSource>>,
}

impl SQLSchemaProvider {
    pub async fn new(provider: Arc<SQLFederationProvider>) -> Result<Self> {
        let tables = Arc::clone(&provider).executor.table_names().await?;

        Self::new_with_tables(provider, tables).await
    }

    pub async fn new_with_tables(
        provider: Arc<SQLFederationProvider>,
        tables: Vec<String>,
    ) -> Result<Self> {
        let futures: Vec<_> = tables
            .into_iter()
            .map(|t| SQLTableSource::new(Arc::clone(&provider), t))
            .collect();
        let results: Result<Vec<_>> = join_all(futures).await.into_iter().collect();
        let sources = results?.into_iter().map(Arc::new).collect();
        Ok(Self::new_with_table_sources(sources))
    }

    pub fn new_with_table_sources(tables: Vec<Arc<SQLTableSource>>) -> Self {
        Self { tables }
    }
}

#[async_trait]
impl SchemaProvider for SQLSchemaProvider {
    fn as_any(&self) -> &dyn Any {
        self
    }

    fn table_names(&self) -> Vec<String> {
        self.tables.iter().map(|s| s.table_name.clone()).collect()
    }

    async fn table(&self, name: &str) -> Result<Option<Arc<dyn TableProvider>>> {
        if let Some(source) = self
            .tables
            .iter()
            .find(|s| s.table_name.eq_ignore_ascii_case(name))
        {
            let adaptor = FederatedTableProviderAdaptor::new(
                Arc::clone(source) as Arc<dyn FederatedTableSource>
            );
            return Ok(Some(Arc::new(adaptor)));
        }
        Ok(None)
    }

    fn table_exist(&self, name: &str) -> bool {
        self.tables
            .iter()
            .any(|s| s.table_name.eq_ignore_ascii_case(name))
    }
}

pub struct MultiSchemaProvider {
    children: Vec<Arc<dyn SchemaProvider>>,
}

impl MultiSchemaProvider {
    pub fn new(children: Vec<Arc<dyn SchemaProvider>>) -> Self {
        Self { children }
    }
}

#[async_trait]
impl SchemaProvider for MultiSchemaProvider {
    fn as_any(&self) -> &dyn Any {
        self
    }

    fn table_names(&self) -> Vec<String> {
        self.children.iter().flat_map(|p| p.table_names()).collect()
    }

    async fn table(&self, name: &str) -> Result<Option<Arc<dyn TableProvider>>> {
        for child in &self.children {
            if let Ok(Some(table)) = child.table(name).await {
                return Ok(Some(table));
            }
        }
        Ok(None)
    }

    fn table_exist(&self, name: &str) -> bool {
        self.children.iter().any(|p| p.table_exist(name))
    }
}

pub struct SQLTableSource {
    provider: Arc<SQLFederationProvider>,
    table_name: String,
    schema: SchemaRef,
}

impl SQLTableSource {
    // creates a SQLTableSource and infers the table schema
    pub async fn new(provider: Arc<SQLFederationProvider>, table_name: String) -> Result<Self> {
        let schema = Arc::clone(&provider)
            .executor
            .get_table_schema(table_name.as_str())
            .await?;
        Self::new_with_schema(provider, table_name, schema)
    }

    pub fn new_with_schema(
        provider: Arc<SQLFederationProvider>,
        table_name: String,
        schema: SchemaRef,
    ) -> Result<Self> {
        Ok(Self {
            provider,
            table_name,
            schema,
        })
    }

    pub fn table_name(&self) -> &str {
        self.table_name.as_str()
    }
}

impl FederatedTableSource for SQLTableSource {
    fn federation_provider(&self) -> Arc<dyn FederationProvider> {
        Arc::clone(&self.provider) as Arc<dyn FederationProvider>
    }
}

impl TableSource for SQLTableSource {
    fn as_any(&self) -> &dyn Any {
        self
    }
    fn schema(&self) -> SchemaRef {
        Arc::clone(&self.schema)
    }
    fn table_type(&self) -> TableType {
        TableType::Temporary
    }
}