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

#![doc = include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/README.md"))]

use http_req::request;
use std::future::Future;

use notion::models::Page;
pub use notion_wasi as notion;

const API_PREFIX: &str = "https://flows.purejs.icu";

extern "C" {
    // Flag if current running is for listening(1) or message receving(0)
    fn is_listening() -> i32;

    // Return the user id of the flows platform
    fn get_flows_user(p: *mut u8) -> i32;

    // Return the flow id
    fn get_flow_id(p: *mut u8) -> i32;

    fn get_event_body_length() -> i32;
    fn get_event_body(p: *mut u8) -> i32;
    fn set_error_log(p: *const u8, len: i32);
}

unsafe fn _get_flows_user() -> String {
    let mut flows_user = Vec::<u8>::with_capacity(100);
    let c = get_flows_user(flows_user.as_mut_ptr());
    flows_user.set_len(c as usize);
    String::from_utf8(flows_user).unwrap()
}

unsafe fn _get_flow_id() -> String {
    let mut flow_id = Vec::<u8>::with_capacity(100);
    let c = get_flow_id(flow_id.as_mut_ptr());
    if c == 0 {
        panic!("Failed to get flow id");
    }
    flow_id.set_len(c as usize);
    String::from_utf8(flow_id).unwrap()
}

/// Revoke previous registered listener of current flow.
///
/// Most of the time you do not need to call this function. As inside
/// the [listen_to_event()] it will revoke previous registered
/// listener, so the only circumstance you need this function is when
/// you want to change the listener from GitHub to others.
pub fn revoke_listeners<S: AsRef<str>>(database: S) {
    unsafe {
        let flows_user = _get_flows_user();
        let flow_id = _get_flow_id();

        let mut writer = Vec::new();
        let res = request::get(
            format!(
                "{}/{}/{}/revoke?database={}",
                API_PREFIX,
                flows_user,
                flow_id,
                database.as_ref(),
            ),
            &mut writer,
        )
        .unwrap();

        match res.status_code().is_success() {
            true => (),
            false => {
                set_error_log(writer.as_ptr(), writer.len() as i32);
            }
        }
    }
}

#[allow(rustdoc::bare_urls)]
/// Create a listener for *https://github.com/`owner`/`repo`*.
///
/// If you have not install
/// [Flows.network platform](https://test.flows.network)'s app to your GitHub,
/// you will receive an error in the flow's building log or running log.
///
/// Before creating the listener, this function will revoke previous
/// registered listener of current flow so you don't need to do it manually.
///
/// `callback` is a callback function which will be called when new `Event` is received.
pub async fn listen_to_event<S, F, Fut>(database: S, callback: F)
where
    S: AsRef<str>,
    F: FnOnce(Page) -> Fut,
    Fut: Future<Output = ()>,
{
    unsafe {
        match is_listening() {
            // Calling register
            1 => {
                let flows_user = _get_flows_user();
                let flow_id = _get_flow_id();

                let mut writer = Vec::new();
                let res = request::get(
                    format!(
                        "{}/{}/{}/listen?database={}",
                        API_PREFIX,
                        flows_user,
                        flow_id,
                        database.as_ref(),
                    ),
                    &mut writer,
                )
                .unwrap();

                match res.status_code().is_success() {
                    true => {
                        if let Ok(event) = serde_json::from_slice(&writer) {
                            callback(event).await;
                        }
                    }
                    false => {
                        set_error_log(writer.as_ptr(), writer.len() as i32);
                    }
                }
            }
            _ => {
                if let Some(event) = event_from_subcription() {
                    callback(event).await;
                }
            }
        }
    }
}

fn event_from_subcription() -> Option<Page> {
    unsafe {
        let l = get_event_body_length();
        let mut event_body = Vec::<u8>::with_capacity(l as usize);
        let c = get_event_body(event_body.as_mut_ptr());
        assert!(c == l);
        event_body.set_len(c as usize);
        match serde_json::from_slice(&event_body) {
            Ok(e) => Some(e),
            Err(_) => None,
        }
    }
}