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

extern crate self as ft_derive;

#[proc_macro_attribute]
pub fn processor(
    _attr: proc_macro::TokenStream,
    item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    handle(item, "processor", "handler")
}

#[proc_macro_attribute]
pub fn wrapped_processor(
    _attr: proc_macro::TokenStream,
    item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    handle(item, "processor", "wrapped_processor")
}

#[proc_macro_attribute]
pub fn data(
    _attr: proc_macro::TokenStream,
    item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    handle(item, "data", "handler")
}

#[proc_macro_attribute]
pub fn form(
    _attr: proc_macro::TokenStream,
    item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    handle(item, "form", "handler")
}

#[proc_macro_attribute]
pub fn migration(
    _attr: proc_macro::TokenStream,
    item: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
    let syn::ItemFn {
        attrs,
        vis,
        sig,
        block,
    } = syn::parse_macro_input!(item as syn::ItemFn);

    let fn_name = &sig.ident;

    let expanded = quote::quote! {
        #[no_mangle]
        pub extern "C" fn migration__entrypoint() -> i32 { // return 0 for success
            let mut conn = match ft_sdk::default_connection() {
                Ok(c) => c,
                Err(e) => {
                    ft_sdk::println!("error when getting connection to apply migration: {e}");
                    return 1;
                }
            };

            match #fn_name(conn) {
                Ok(()) => 0,
                Err(e) => {
                    ft_sdk::println!("error when applying migration: {e}");
                    1
                }
            }
        }

        #(#attrs)*
        #vis #sig {
            #block
        }
    };

    // println!("{expanded}");
    proc_macro::TokenStream::from(expanded)
}

fn handle(item: proc_macro::TokenStream, kind: &str, handler: &str) -> proc_macro::TokenStream {
    let syn::ItemFn {
        attrs,
        vis,
        sig,
        block,
    } = syn::parse_macro_input!(item as syn::ItemFn);

    let fn_name = &sig.ident;
    let fn_name_entrypoint =
        syn::Ident::new(format!("{}__entrypoint", fn_name).as_str(), fn_name.span());
    let return_type: syn::Type =
        syn::parse_str(format!("ft_sdk::{kind}::Result").as_str()).unwrap();
    let handler: syn::Path =
        syn::parse_str(format!("ft_sdk::from_request::{handler}::handle").as_str()).unwrap();

    match sig.output {
        syn::ReturnType::Default => {
            return compiler_error(
                format!("The return type must be ft_sdk::{kind}::Result").as_str(),
            );
        }
        syn::ReturnType::Type(_, ref ty) => {
            if ty.as_ref() != &return_type {
                return compiler_error(
                    format!(
                        "The return type must be ft_sdk::{kind}::Result, not {}.",
                        proc_macro::TokenStream::from(quote::quote! { #ty })
                    )
                    .as_str(),
                );
            }
        }
    };

    let expanded = quote::quote! {
        #[no_mangle]
        pub extern "C" fn #fn_name_entrypoint() {
            #handler(#fn_name)
        }

        #(#attrs)*
        #vis #sig {
            #block
        }
    };

    // println!("{expanded}");
    proc_macro::TokenStream::from(expanded)
}

fn compiler_error(msg: &str) -> proc_macro::TokenStream {
    proc_macro::TokenStream::from(quote::quote! {
        compile_error!(#msg);
    })
}