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

// Copyright 2023 Greptime Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::fmt;

use common_error::ext::{BoxedError, PlainError};
use common_error::status_code::StatusCode;
use common_query::error::{self, InvalidFuncArgsSnafu, Result};
use common_query::prelude::{Signature, TypeSignature};
use datafusion::logical_expr::Volatility;
use datatypes::prelude::ConcreteDataType;
use datatypes::scalars::ScalarVectorBuilder;
use datatypes::value::Value;
use datatypes::vectors::{MutableVector, StringVectorBuilder, VectorRef};
use geohash::Coord;
use snafu::{ensure, ResultExt};

use crate::function::{Function, FunctionContext};

/// Function that return geohash string for a given geospatial coordinate.
#[derive(Clone, Debug, Default)]
pub struct GeohashFunction;

const NAME: &str = "geohash";

impl Function for GeohashFunction {
    fn name(&self) -> &str {
        NAME
    }

    fn return_type(&self, _input_types: &[ConcreteDataType]) -> Result<ConcreteDataType> {
        Ok(ConcreteDataType::string_datatype())
    }

    fn signature(&self) -> Signature {
        let mut signatures = Vec::new();
        for coord_type in &[
            ConcreteDataType::float32_datatype(),
            ConcreteDataType::float64_datatype(),
        ] {
            for resolution_type in &[
                ConcreteDataType::int8_datatype(),
                ConcreteDataType::int16_datatype(),
                ConcreteDataType::int32_datatype(),
                ConcreteDataType::int64_datatype(),
                ConcreteDataType::uint8_datatype(),
                ConcreteDataType::uint16_datatype(),
                ConcreteDataType::uint32_datatype(),
                ConcreteDataType::uint64_datatype(),
            ] {
                signatures.push(TypeSignature::Exact(vec![
                    // latitude
                    coord_type.clone(),
                    // longitude
                    coord_type.clone(),
                    // resolution
                    resolution_type.clone(),
                ]));
            }
        }
        Signature::one_of(signatures, Volatility::Stable)
    }

    fn eval(&self, _func_ctx: FunctionContext, columns: &[VectorRef]) -> Result<VectorRef> {
        ensure!(
            columns.len() == 3,
            InvalidFuncArgsSnafu {
                err_msg: format!(
                    "The length of the args is not correct, expect 3, provided : {}",
                    columns.len()
                ),
            }
        );

        let lat_vec = &columns[0];
        let lon_vec = &columns[1];
        let resolution_vec = &columns[2];

        let size = lat_vec.len();
        let mut results = StringVectorBuilder::with_capacity(size);

        for i in 0..size {
            let lat = lat_vec.get(i).as_f64_lossy();
            let lon = lon_vec.get(i).as_f64_lossy();
            let r = match resolution_vec.get(i) {
                Value::Int8(v) => v as usize,
                Value::Int16(v) => v as usize,
                Value::Int32(v) => v as usize,
                Value::Int64(v) => v as usize,
                Value::UInt8(v) => v as usize,
                Value::UInt16(v) => v as usize,
                Value::UInt32(v) => v as usize,
                Value::UInt64(v) => v as usize,
                _ => unreachable!(),
            };

            let result = match (lat, lon) {
                (Some(lat), Some(lon)) => {
                    let coord = Coord { x: lon, y: lat };
                    let encoded = geohash::encode(coord, r)
                        .map_err(|e| {
                            BoxedError::new(PlainError::new(
                                format!("Geohash error: {}", e),
                                StatusCode::EngineExecuteQuery,
                            ))
                        })
                        .context(error::ExecuteSnafu)?;
                    Some(encoded)
                }
                _ => None,
            };

            results.push(result.as_deref());
        }

        Ok(results.to_vector())
    }
}

impl fmt::Display for GeohashFunction {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", NAME)
    }
}