aboutsummaryrefslogtreecommitdiff
path: root/src/imap/mailbox_view.rs
blob: b0ad95abb120cb44d16004707100b1992fcd1347 (plain) (blame)
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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
use std::borrow::Borrow;
use std::num::NonZeroU32;
use std::sync::Arc;

use anyhow::{anyhow, bail, Error, Result};
use boitalettres::proto::res::body::Data as Body;
use chrono::{Offset, TimeZone, Utc};
use futures::stream::{FuturesOrdered, StreamExt};
use imap_codec::types::address::Address;
use imap_codec::types::body::{BasicFields, Body as FetchBody, BodyStructure, SpecificFields};
use imap_codec::types::core::{Atom, IString, NString, NonZeroBytes};
use imap_codec::types::datetime::MyDateTime;
use imap_codec::types::envelope::Envelope;
use imap_codec::types::fetch_attributes::{FetchAttribute, MacroOrFetchAttributes};
use imap_codec::types::flag::Flag;
use imap_codec::types::response::{Code, Data, MessageAttribute, Status};
use imap_codec::types::sequence::{self, SequenceSet};
use mail_parser::*;

use crate::mail::mailbox::Mailbox;
use crate::mail::uidindex::UidIndex;

const DEFAULT_FLAGS: [Flag; 5] = [
    Flag::Seen,
    Flag::Answered,
    Flag::Flagged,
    Flag::Deleted,
    Flag::Draft,
];

/// A MailboxView is responsible for giving the client the information
/// it needs about a mailbox, such as an initial summary of the mailbox's
/// content and continuous updates indicating when the content
/// of the mailbox has been changed.
/// To do this, it keeps a variable `known_state` that corresponds to
/// what the client knows, and produces IMAP messages to be sent to the
/// client that go along updates to `known_state`.
pub struct MailboxView {
    mailbox: Arc<Mailbox>,
    known_state: UidIndex,
}

impl MailboxView {
    /// Creates a new IMAP view into a mailbox.
    /// Generates the necessary IMAP messages so that the client
    /// has a satisfactory summary of the current mailbox's state.
    /// These are the messages that are sent in response to a SELECT command.
    pub async fn new(mailbox: Arc<Mailbox>) -> Result<(Self, Vec<Body>)> {
        // TODO THIS IS JUST A TEST REMOVE LATER
        mailbox.test().await?;

        let state = mailbox.current_uid_index().await;

        let new_view = Self {
            mailbox,
            known_state: state,
        };

        let mut data = Vec::<Body>::new();
        data.push(new_view.exists()?);
        data.push(new_view.recent()?);
        data.extend(new_view.flags()?.into_iter());
        data.push(new_view.uidvalidity()?);
        data.push(new_view.uidnext()?);
        if let Some(unseen) = new_view.unseen()? {
            data.push(unseen);
        }

        Ok((new_view, data))
    }

    /// Looks up state changes in the mailbox and produces a set of IMAP
    /// responses describing the changes.
    pub async fn sync_update(&mut self) -> Result<Vec<Body>> {
        self.mailbox.sync().await?;
        // TODO THIS IS JUST A TEST REMOVE LATER
        self.mailbox.test().await?;

        self.update().await
    }

    /// Produces a set of IMAP responses describing the change between
    /// what the client knows and what is actually in the mailbox.
    pub async fn update(&mut self) -> Result<Vec<Body>> {
        let new_view = MailboxView {
            mailbox: self.mailbox.clone(),
            known_state: self.mailbox.current_uid_index().await,
        };

        let mut data = Vec::<Body>::new();

        if new_view.known_state.uidvalidity != self.known_state.uidvalidity {
            // TODO: do we want to push less/more info than this?
            data.push(new_view.uidvalidity()?);
            data.push(new_view.exists()?);
            data.push(new_view.uidnext()?);
        } else {
            // Calculate diff between two mailbox states
            // See example in IMAP RFC in section on NOOP command:
            // we want to produce something like this:
            // C: a047 NOOP
            // S: * 22 EXPUNGE
            // S: * 23 EXISTS
            // S: * 14 FETCH (UID 1305 FLAGS (\Seen \Deleted))
            // S: a047 OK Noop completed
            // In other words:
            // - notify client of expunged mails
            // - if new mails arrived, notify client of number of existing mails
            // - if flags changed for existing mails, tell client

            // - notify client of expunged mails
            let mut n_expunge = 0;
            for (i, (_uid, uuid)) in self.known_state.idx_by_uid.iter().enumerate() {
                if !new_view.known_state.table.contains_key(uuid) {
                    data.push(Body::Data(Data::Expunge(
                        NonZeroU32::try_from((i + 1 - n_expunge) as u32).unwrap(),
                    )));
                    n_expunge += 1;
                }
            }

            // - if new mails arrived, notify client of number of existing mails
            if new_view.known_state.table.len() != self.known_state.table.len() - n_expunge {
                data.push(new_view.exists()?);
            }

            // - if flags changed for existing mails, tell client
            for (i, (_uid, uuid)) in new_view.known_state.idx_by_uid.iter().enumerate() {
                let old_mail = self.known_state.table.get(uuid);
                let new_mail = new_view.known_state.table.get(uuid);
                if old_mail.is_some() && old_mail != new_mail {
                    if let Some((uid, flags)) = new_mail {
                        data.push(Body::Data(Data::Fetch {
                            seq_or_uid: NonZeroU32::try_from((i + 1) as u32).unwrap(),
                            attributes: vec![
                                MessageAttribute::Uid((*uid).try_into().unwrap()),
                                MessageAttribute::Flags(
                                    flags.iter().filter_map(|f| string_to_flag(f)).collect(),
                                ),
                            ],
                        }));
                    }
                }
            }
        }

        *self = new_view;
        Ok(data)
    }

    /// Looks up state changes in the mailbox and produces a set of IMAP
    /// responses describing the new state.
    pub async fn fetch(
        &self,
        sequence_set: &SequenceSet,
        attributes: &MacroOrFetchAttributes,
        uid: &bool,
    ) -> Result<Vec<Body>> {
        if *uid {
            bail!("UID FETCH not implemented");
        }

        let mail_vec = self
            .known_state
            .idx_by_uid
            .iter()
            .map(|(uid, uuid)| (*uid, *uuid))
            .collect::<Vec<_>>();

        let mut mails = vec![];
        let iter_strat = sequence::Strategy::Naive {
            largest: NonZeroU32::try_from((self.known_state.idx_by_uid.len() + 1) as u32).unwrap(),
        };
        for i in sequence_set.iter(iter_strat) {
            if let Some(mail) = mail_vec.get(i.get() as usize - 1) {
                mails.push((i, *mail));
            } else {
                bail!("No such mail: {}", i);
            }
        }

        let mails_uuid = mails
            .iter()
            .map(|(_i, (_uid, uuid))| *uuid)
            .collect::<Vec<_>>();
        let mails_meta = self.mailbox.fetch_meta(&mails_uuid).await?;

        let fetch_attrs = match attributes {
            MacroOrFetchAttributes::Macro(m) => m.expand(),
            MacroOrFetchAttributes::FetchAttributes(a) => a.clone(),
        };
        let need_body = fetch_attrs.iter().any(|x| {
            matches!(
                x,
                FetchAttribute::Body
                    | FetchAttribute::BodyExt { .. }
                    | FetchAttribute::Rfc822
                    | FetchAttribute::Rfc822Text
                    | FetchAttribute::BodyStructure
            )
        });

        let mails = if need_body {
            let mut iter = mails
                .into_iter()
                .zip(mails_meta.into_iter())
                .map(|((i, (uid, uuid)), meta)| async move {
                    let body = self.mailbox.fetch_full(uuid, &meta.message_key).await?;
                    Ok::<_, anyhow::Error>((i, uid, uuid, meta, Some(body)))
                })
                .collect::<FuturesOrdered<_>>();
            let mut mails = vec![];
            while let Some(m) = iter.next().await {
                mails.push(m?);
            }
            mails
        } else {
            mails
                .into_iter()
                .zip(mails_meta.into_iter())
                .map(|((i, (uid, uuid)), meta)| (i, uid, uuid, meta, None))
                .collect::<Vec<_>>()
        };

        let mut ret = vec![];
        for (i, uid, uuid, meta, body) in mails {
            let mut attributes = vec![MessageAttribute::Uid(uid)];

            let (_uid2, flags) = self
                .known_state
                .table
                .get(&uuid)
                .ok_or_else(|| anyhow!("Mail not in uidindex table: {}", uuid))?;

            let parsed = match &body {
                Some(m) => {
                    mail_parser::Message::parse(m).ok_or_else(|| anyhow!("Invalid mail body"))?
                }
                None => mail_parser::Message::parse(&meta.headers)
                    .ok_or_else(|| anyhow!("Invalid mail headers"))?,
            };

            for attr in fetch_attrs.iter() {
                match attr {
                    FetchAttribute::Uid => (),
                    FetchAttribute::Flags => {
                        attributes.push(MessageAttribute::Flags(
                            flags.iter().filter_map(|f| string_to_flag(f)).collect(),
                        ));
                    }
                    FetchAttribute::Rfc822Size => {
                        attributes.push(MessageAttribute::Rfc822Size(meta.rfc822_size as u32))
                    }
                    FetchAttribute::Rfc822Header => attributes.push(
                        MessageAttribute::Rfc822Header(NString(Some(IString::Literal(
                            meta.headers
                                .clone()
                                .try_into()
                                .or(Err(Error::msg("IString conversion error")))?,
                        )))),
                    ),
                    FetchAttribute::Rfc822Text => {
                        let r = parsed
                            .raw_message.get(parsed.offset_body..parsed.offset_end)
                            .ok_or(Error::msg("Unable to extract email body, cursors out of bound. This is a bug."))?
                            .try_into()
                            .or(Err(Error::msg("IString conversion error")))?;

                        attributes.push(MessageAttribute::Rfc822Text(NString(Some(
                            IString::Literal(r),
                        ))))
                    }
                    FetchAttribute::Rfc822 => {
                        attributes.push(MessageAttribute::Rfc822(NString(Some(IString::Literal(
                            body.as_ref().unwrap().clone().try_into().unwrap(),
                        )))))
                    }
                    FetchAttribute::Envelope => {
                        attributes.push(MessageAttribute::Envelope(message_envelope(&parsed)))
                    }
                    FetchAttribute::Body => {
                        /*
                                                 * CAPTURE:
                        b fetch 29878:29879 (BODY)
                        * 29878 FETCH (BODY (("text" "plain" ("charset" "utf-8") NIL NIL "quoted-printable" 3264 82)("text" "html" ("charset" "utf-8") NIL NIL "quoted-printable" 31834 643) "alternative"))
                        * 29879 FETCH (BODY ("text" "html" ("charset" "us-ascii") NIL NIL "7bit" 4107 131))
                                                           ^^^^^^^^^^^^^^^^^^^^^^ ^^^ ^^^ ^^^^^^ ^^^^ ^^^
                                                           |                      |   |   |      |    | number of lines
                                                           |                      |   |   |      | size
                                                           |                      |   |   | content transfer encoding
                                                           |                      |   | description
                                                           |                      | id
                                                           | parameter list
                        b OK Fetch completed (0.001 + 0.000 secs).
                                                *
                                                */

                        /*match parsed.structure {
                            Part(part_id) => {
                                match parsed.parts.get(part_id)? {
                                    Text(
                                    let fb = FetchBody {
                                        parameter_list: vec![],
                                        id: NString(None),
                                        descritpion: NString(None),
                                        // Default value is 7bit"
                                        // https://datatracker.ietf.org/doc/html/rfc2045#section-6.1
                                        content_transfer_encoding: IString::try_from("7bit").unwrap(),
                                    };
                                }
                            }
                            List(part_list) => todo!(),
                            MultiPart((first, rest)) => todo!(),
                        }*/

                        // @TODO This is a stub
                        let is = IString::try_from("test").unwrap();
                        let b = BodyStructure::Single {
                            body: FetchBody {
                                basic: BasicFields {
                                    parameter_list: vec![],
                                    id: NString(Some(is.clone())),
                                    description: NString(Some(is.clone())),
                                    content_transfer_encoding: is.clone(),
                                    size: 1,
                                },
                                specific: SpecificFields::Text {
                                    // @FIXME I do not understand yet how this part works
                                    subtype: is,
                                    number_of_lines: 1,
                                },
                            },
                            // Always None for Body, can be populated for BodyStructure
                            extension: None,
                        };

                        attributes.push(MessageAttribute::Body(b));
                    }
                    FetchAttribute::BodyExt {
                        section,
                        partial,
                        peek,
                    } => {
                        // @TODO This is a stub
                        let is = IString::try_from("test").unwrap();

                        attributes.push(MessageAttribute::BodyExt {
                            section: None,
                            origin: None,
                            data: NString(Some(is)),
                        })
                    }
                    FetchAttribute::BodyStructure => {
                        // @TODO This is a stub
                        let is = IString::try_from("test").unwrap();
                        let b = BodyStructure::Single {
                            body: FetchBody {
                                basic: BasicFields {
                                    parameter_list: vec![],
                                    id: NString(Some(is.clone())),
                                    description: NString(Some(is.clone())),
                                    content_transfer_encoding: is.clone(),
                                    size: 1,
                                },
                                specific: SpecificFields::Text {
                                    // @FIXME I do not understand yet how this part works
                                    subtype: is,
                                    number_of_lines: 1,
                                },
                            },
                            // Always None for Body, can be populated for BodyStructure
                            extension: None,
                        };

                        attributes.push(MessageAttribute::BodyStructure(b));
                    }
                    FetchAttribute::InternalDate => {
                        attributes.push(MessageAttribute::InternalDate(MyDateTime(
                            Utc.fix()
                                .timestamp(i64::try_from(meta.internaldate / 1000)?, 0),
                        )));
                    }
                }
            }

            ret.push(Body::Data(Data::Fetch {
                seq_or_uid: i,
                attributes,
            }));
        }

        Ok(ret)
    }

    // ----

    /// Produce an OK [UIDVALIDITY _] message corresponding to `known_state`
    fn uidvalidity(&self) -> Result<Body> {
        let uid_validity = Status::ok(
            None,
            Some(Code::UidValidity(self.known_state.uidvalidity)),
            "UIDs valid",
        )
        .map_err(Error::msg)?;
        Ok(Body::Status(uid_validity))
    }

    /// Produce an OK [UIDNEXT _] message corresponding to `known_state`
    fn uidnext(&self) -> Result<Body> {
        let next_uid = Status::ok(
            None,
            Some(Code::UidNext(self.known_state.uidnext)),
            "Predict next UID",
        )
        .map_err(Error::msg)?;
        Ok(Body::Status(next_uid))
    }

    /// Produces an UNSEEN message (if relevant) corresponding to the
    /// first unseen message id in `known_state`
    fn unseen(&self) -> Result<Option<Body>> {
        let unseen = self
            .known_state
            .idx_by_flag
            .get(&"$unseen".to_string())
            .and_then(|os| os.get_min())
            .cloned();
        if let Some(unseen) = unseen {
            let status_unseen =
                Status::ok(None, Some(Code::Unseen(unseen.clone())), "First unseen UID")
                    .map_err(Error::msg)?;
            Ok(Some(Body::Status(status_unseen)))
        } else {
            Ok(None)
        }
    }

    /// Produce an EXISTS message corresponding to the number of mails
    /// in `known_state`
    fn exists(&self) -> Result<Body> {
        let exists = u32::try_from(self.known_state.idx_by_uid.len())?;
        Ok(Body::Data(Data::Exists(exists)))
    }

    /// Produce a RECENT message corresponding to the number of
    /// recent mails in `known_state`
    fn recent(&self) -> Result<Body> {
        let recent = self
            .known_state
            .idx_by_flag
            .get(&"\\Recent".to_string())
            .map(|os| os.len())
            .unwrap_or(0);
        let recent = u32::try_from(recent)?;
        Ok(Body::Data(Data::Recent(recent)))
    }

    /// Produce a FLAGS and a PERMANENTFLAGS message that indicates
    /// the flags that are in `known_state` + default flags
    fn flags(&self) -> Result<Vec<Body>> {
        let mut flags: Vec<Flag> = self
            .known_state
            .idx_by_flag
            .flags()
            .map(|f| string_to_flag(f))
            .flatten()
            .collect();
        for f in DEFAULT_FLAGS.iter() {
            if !flags.contains(f) {
                flags.push(f.clone());
            }
        }
        let mut ret = vec![Body::Data(Data::Flags(flags.clone()))];

        flags.push(Flag::Permanent);
        let permanent_flags =
            Status::ok(None, Some(Code::PermanentFlags(flags)), "Flags permitted")
                .map_err(Error::msg)?;
        ret.push(Body::Status(permanent_flags));

        Ok(ret)
    }
}

fn string_to_flag(f: &str) -> Option<Flag> {
    match f.chars().next() {
        Some('\\') => None,
        Some('$') if f == "$unseen" => None,
        Some(_) => match Atom::try_from(f.clone()) {
            Err(_) => {
                tracing::error!(flag=%f, "Unable to encode flag as IMAP atom");
                None
            }
            Ok(a) => Some(Flag::Keyword(a)),
        },
        None => None,
    }
}

fn message_envelope(msg: &mail_parser::Message<'_>) -> Envelope {
    Envelope {
        date: NString(
            msg.get_date()
                .map(|d| IString::try_from(d.to_iso8601()).unwrap()),
        ),
        subject: NString(
            msg.get_subject()
                .map(|d| IString::try_from(d.to_string()).unwrap()),
        ),
        from: convert_addresses(msg.get_from()),
        sender: convert_addresses(msg.get_sender()),
        reply_to: convert_addresses(msg.get_reply_to()),
        to: convert_addresses(msg.get_to()),
        cc: convert_addresses(msg.get_cc()),
        bcc: convert_addresses(msg.get_bcc()),
        in_reply_to: NString(None), // TODO
        message_id: NString(
            msg.get_message_id()
                .map(|d| IString::try_from(d.to_string()).unwrap()),
        ),
    }
}

fn convert_addresses(a: &mail_parser::HeaderValue<'_>) -> Vec<Address> {
    match a {
        mail_parser::HeaderValue::Address(a) => vec![convert_address(a)],
        mail_parser::HeaderValue::AddressList(a) => {
            let mut ret = vec![];
            for aa in a {
                ret.push(convert_address(aa));
            }
            ret
        }
        mail_parser::HeaderValue::Empty => vec![],
        mail_parser::HeaderValue::Collection(c) => {
            let mut ret = vec![];
            for cc in c.iter() {
                ret.extend(convert_addresses(cc).into_iter());
            }
            ret
        }
        _ => panic!("Invalid address header"),
    }
}

fn convert_address(a: &mail_parser::Addr<'_>) -> Address {
    let (user, host) = match &a.address {
        None => (None, None),
        Some(x) => match x.split_once('@') {
            Some((u, h)) => (Some(u.to_string()), Some(h.to_string())),
            None => (Some(x.to_string()), None),
        },
    };

    Address::new(
        NString(
            a.name
                .as_ref()
                .map(|x| IString::try_from(x.to_string()).unwrap()),
        ),
        NString(None),
        NString(user.map(|x| IString::try_from(x).unwrap())),
        NString(host.map(|x| IString::try_from(x).unwrap())),
    )
}

fn build_imap_email_struct<'a>(
    msg: &Message<'a>,
    node: &MessageStructure,
) -> Result<BodyStructure> {
    match node {
        MessageStructure::Part(id) => {
            let part = msg.parts.get(*id).ok_or(anyhow!(
                "Email part referenced in email structure is missing"
            ))?;
            match part {
                MessagePart::Text(bp) => Ok(BodyStructure::Single {
                    body: FetchBody {
                        basic: BasicFields {
                            parameter_list: vec![], //@TODO
                            id: match bp.headers_rfc.get(&RfcHeader::ContentId) {
                                Some(HeaderValue::Text(v)) => {
                                    NString(IString::try_from(v.clone().into_owned()).ok())
                                }
                                _ => NString(None),
                            },
                            description: NString(None), //@TODO
                            content_transfer_encoding: match bp
                                .headers_rfc
                                .get(&RfcHeader::ContentTransferEncoding)
                            {
                                Some(HeaderValue::Text(v)) => {
                                    IString::try_from(v.clone().into_owned())
                                        .unwrap_or(unchecked_istring("7bit"))
                                }
                                _ => unchecked_istring("7bit"),
                            },
                            size: u32::try_from(bp.len())?,
                        },
                        specific: SpecificFields::Text {
                            subtype: match bp.headers_rfc.get(&RfcHeader::ContentType) {
                                Some(HeaderValue::ContentType(ContentType {
                                    c_subtype: Some(st),
                                    ..
                                })) => IString::try_from(st.clone().into_owned())
                                    .unwrap_or(unchecked_istring("plain")),
                                _ => unchecked_istring("plain"),
                            },
                            number_of_lines: u32::try_from(bp.get_text_contents().lines().count())?,
                        },
                    },
                    extension: None,
                }),
                MessagePart::Multipart(_) => {
                    unreachable!("A multipart entry can not be found here.")
                }
                _ => todo!(),
            }
        }
        MessageStructure::List(l) => todo!(),
        /*BodyStructure::Multi {
            bodies: l.map(|inner_node| build_email_struct(msg, inner_node)),
            subtype: "",
            extension_data: None,
        },*/
        MessageStructure::MultiPart((id, l)) => {
            todo!()
            /*let part = msg.parts.get(id)?;
            let mp = match part {
                MessagePart::Multipart(mp) => mp,
                _ => unreachable!("Only a MessagePart part entry is allowed here.");
            }


            BodyStructure::Multi {
                bodies: l.map(|inner_node| build_email_struct(msg, inner_node)),
                subtype: "",
                extension_data: Some(MultipartExtensionData {
                    parameter_list: vec![],
                    disposition: None,
                    language: None,
                    location: None,
                    extension: vec![],
                })
            }
            */
        }
    }
}

/// s is set to static to ensure that only compile time values
/// checked by the developpers are passed.
fn unchecked_istring(s: &'static str) -> IString {
    IString::try_from(s).expect("this value is expected to be a valid imap-codec::IString")
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn rfc_to_imap() -> Result<()> {
        let txt = br#"From: Garage team <garagehq@deuxfleurs.fr>
Subject: Welcome to Aerogramme!!

This is just a test email, feel free to ignore.
"#;
        let message = Message::parse(txt).unwrap();

        let bs = build_imap_email_struct(&message, &message.structure)?;

        print!("{:?}", bs);

        Ok(())
    }
}