use anyhow::{bail, Result};
use std::io::Write;
use std::net::TcpStream;
use std::thread;

use crate::common::constants::*;
use crate::common::*;

/// These fragments are not a generic IMAP client
/// but specialized to our specific tests. They can't take
/// arbitrary values, only enum for which the code is known
/// to be correct. The idea is that the generated message is more
/// or less hardcoded by the developer, so its clear what's expected,
/// and not generated by a library. Also don't use vector of enum,
/// as it again introduce some kind of genericity we try so hard to avoid:
/// instead add a dedicated enum, for example "All" or anything relaevent that would
/// describe your list and then hardcode it in your fragment.
/// DON'T. TRY. TO. BE. GENERIC. HERE.

pub fn connect(imap: &mut TcpStream) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];

    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(&read[..4], &b"* OK"[..]);

    Ok(())
}

pub enum Account {
    Alice,
}

pub enum Extension {
    None,
    Unselect,
    Move,
    Condstore,
    LiteralPlus,
    Idle,
    UidPlus,
    ListStatus,
}

pub enum Enable {
    Utf8Accept,
    CondStore,
    All,
}

pub enum Mailbox {
    Inbox,
    Archive,
    Drafts,
}

pub enum Flag {
    Deleted,
    Important,
}

pub enum Email {
    Basic,
    Multipart,
}

pub enum Selection {
    FirstId,
    SecondId,
    All,
}

pub enum SelectMod {
    None,
    Condstore,
}

pub enum StoreAction {
    AddFlags,
    DelFlags,
    SetFlags,
    AddFlagsSilent,
    DelFlagsSilent,
    SetFlagsSilent,
}

pub enum StoreMod {
    None,
    UnchangedSince(u64),
}

pub enum FetchKind {
    Rfc822,
    Rfc822Size,
}

pub enum FetchMod {
    None,
    ChangedSince(u64),
}

pub enum SearchKind<'a> {
    Text(&'a str),
    ModSeq(u64),
}

pub enum StatusKind {
    UidNext,
    HighestModSeq,
}

pub enum MbxSelect {
    All,
}

pub enum ListReturn {
    None,
    StatusMessagesUnseen,
}

pub fn capability(imap: &mut TcpStream, ext: Extension) -> Result<()> {
    imap.write(&b"5 capability\r\n"[..])?;

    let maybe_ext = match ext {
        Extension::None => None,
        Extension::Unselect => Some("UNSELECT"),
        Extension::Move => Some("MOVE"),
        Extension::Condstore => Some("CONDSTORE"),
        Extension::LiteralPlus => Some("LITERAL+"),
        Extension::Idle => Some("IDLE"),
        Extension::UidPlus => Some("UIDPLUS"),
        Extension::ListStatus => Some("LIST-STATUS"),
    };

    let mut buffer: [u8; 6000] = [0; 6000];
    let read = read_lines(imap, &mut buffer, Some(&b"5 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    assert!(srv_msg.contains("IMAP4REV1"));
    if let Some(ext) = maybe_ext {
        assert!(srv_msg.contains(ext));
    }

    Ok(())
}

pub fn login(imap: &mut TcpStream, account: Account) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];

    assert!(matches!(account, Account::Alice));
    imap.write(&b"10 login alice hunter2\r\n"[..])?;

    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(&read[..5], &b"10 OK"[..]);

    Ok(())
}

pub fn login_with_literal(imap: &mut TcpStream, account: Account) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];

    assert!(matches!(account, Account::Alice));
    imap.write(&b"10 login {5+}\r\nalice {7+}\r\nhunter2\r\n"[..])?;
    let _read = read_lines(imap, &mut buffer, Some(&b"10 OK"[..]))?;
    Ok(())
}

pub fn create_mailbox(imap: &mut TcpStream, mbx: Mailbox) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];

    let mbx_str = match mbx {
        Mailbox::Inbox => "INBOX",
        Mailbox::Archive => "ArchiveCustom",
        Mailbox::Drafts => "DraftsCustom",
    };

    let cmd = format!("15 create {}\r\n", mbx_str);
    imap.write(cmd.as_bytes())?;
    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(&read[..12], &b"15 OK CREATE"[..]);

    Ok(())
}

pub fn list(imap: &mut TcpStream, select: MbxSelect, mod_return: ListReturn) -> Result<String> {
    let mut buffer: [u8; 6000] = [0; 6000];

    let select_str = match select {
        MbxSelect::All => "%",
    };

    let mod_return_str = match mod_return {
        ListReturn::None => "",
        ListReturn::StatusMessagesUnseen => " RETURN (STATUS (MESSAGES UNSEEN))",
    };

    imap.write(format!("19 LIST \"\" \"{}\"{}\r\n", select_str, mod_return_str).as_bytes())?;

    let read = read_lines(imap, &mut buffer, Some(&b"19 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    Ok(srv_msg.to_string())
}

pub fn select(imap: &mut TcpStream, mbx: Mailbox, modifier: SelectMod) -> Result<String> {
    let mut buffer: [u8; 6000] = [0; 6000];

    let mbx_str = match mbx {
        Mailbox::Inbox => "INBOX",
        Mailbox::Archive => "ArchiveCustom",
        Mailbox::Drafts => "DraftsCustom",
    };

    let mod_str = match modifier {
        SelectMod::Condstore => " (CONDSTORE)",
        SelectMod::None => "",
    };

    imap.write(format!("20 select {}{}\r\n", mbx_str, mod_str).as_bytes())?;

    let read = read_lines(imap, &mut buffer, Some(&b"20 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;

    Ok(srv_msg.to_string())
}

pub fn unselect(imap: &mut TcpStream) -> Result<()> {
    imap.write(&b"70 unselect\r\n"[..])?;
    let mut buffer: [u8; 1500] = [0; 1500];
    let _read = read_lines(imap, &mut buffer, Some(&b"70 OK"[..]))?;

    Ok(())
}

pub fn check(imap: &mut TcpStream) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];

    imap.write(&b"21 check\r\n"[..])?;
    let _read = read_lines(imap, &mut buffer, Some(&b"21 OK"[..]))?;

    Ok(())
}

pub fn status(imap: &mut TcpStream, mbx: Mailbox, sk: StatusKind) -> Result<String> {
    let mbx_str = match mbx {
        Mailbox::Inbox => "INBOX",
        Mailbox::Archive => "ArchiveCustom",
        Mailbox::Drafts => "DraftsCustom",
    };
    let sk_str = match sk {
        StatusKind::UidNext => "(UIDNEXT)",
        StatusKind::HighestModSeq => "(HIGHESTMODSEQ)",
    };
    imap.write(format!("25 STATUS {} {}\r\n", mbx_str, sk_str).as_bytes())?;
    let mut buffer: [u8; 6000] = [0; 6000];
    let read = read_lines(imap, &mut buffer, Some(&b"25 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;

    Ok(srv_msg.to_string())
}

pub fn lmtp_handshake(lmtp: &mut TcpStream) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];

    let _read = read_lines(lmtp, &mut buffer, None)?;
    assert_eq!(&buffer[..4], &b"220 "[..]);

    lmtp.write(&b"LHLO example.tld\r\n"[..])?;
    let _read = read_lines(lmtp, &mut buffer, Some(&b"250 "[..]))?;

    Ok(())
}

pub fn lmtp_deliver_email(lmtp: &mut TcpStream, email_type: Email) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];

    let email = match email_type {
        Email::Basic => EMAIL2,
        Email::Multipart => EMAIL1,
    };
    lmtp.write(&b"MAIL FROM:<bob@example.tld>\r\n"[..])?;
    let _read = read_lines(lmtp, &mut buffer, Some(&b"250 2.0.0"[..]))?;

    lmtp.write(&b"RCPT TO:<alice@example.tld>\r\n"[..])?;
    let _read = read_lines(lmtp, &mut buffer, Some(&b"250 2.1.5"[..]))?;

    lmtp.write(&b"DATA\r\n"[..])?;
    let _read = read_lines(lmtp, &mut buffer, Some(&b"354 "[..]))?;

    lmtp.write(email)?;
    lmtp.write(&b"\r\n.\r\n"[..])?;
    let _read = read_lines(lmtp, &mut buffer, Some(&b"250 2.0.0"[..]))?;

    Ok(())
}

pub fn noop_exists(imap: &mut TcpStream, must_exists: u32) -> Result<()> {
    let mut buffer: [u8; 6000] = [0; 6000];

    let mut max_retry = 20;
    loop {
        max_retry -= 1;
        imap.write(&b"30 NOOP\r\n"[..])?;
        let read = read_lines(imap, &mut buffer, Some(&b"30 OK"[..]))?;
        let srv_msg = std::str::from_utf8(read)?;

        for line in srv_msg.lines() {
            if line.contains("EXISTS") {
                let got = read_first_u32(line)?;
                if got == must_exists {
                    // Done
                    return Ok(());
                }
            }
        }

        if max_retry <= 0 {
            // Failed
            bail!("no more retry");
        }

        thread::sleep(SMALL_DELAY);
    }
}

pub fn fetch(
    imap: &mut TcpStream,
    selection: Selection,
    kind: FetchKind,
    modifier: FetchMod,
) -> Result<String> {
    let mut buffer: [u8; 65535] = [0; 65535];

    let sel_str = match selection {
        Selection::FirstId => "1",
        Selection::SecondId => "2",
        Selection::All => "1:*",
    };

    let kind_str = match kind {
        FetchKind::Rfc822 => "RFC822",
        FetchKind::Rfc822Size => "RFC822.SIZE",
    };

    let mod_str = match modifier {
        FetchMod::None => "".into(),
        FetchMod::ChangedSince(val) => format!(" (CHANGEDSINCE {})", val),
    };

    imap.write(format!("40 fetch {} {}{}\r\n", sel_str, kind_str, mod_str).as_bytes())?;

    let read = read_lines(imap, &mut buffer, Some(&b"40 OK FETCH"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;

    Ok(srv_msg.to_string())
}

pub fn copy(imap: &mut TcpStream, selection: Selection, to: Mailbox) -> Result<String> {
    let mut buffer: [u8; 65535] = [0; 65535];
    assert!(matches!(selection, Selection::FirstId));
    assert!(matches!(to, Mailbox::Archive));

    imap.write(&b"45 copy 1 ArchiveCustom\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(&read[..5], &b"45 OK"[..]);
    let srv_msg = std::str::from_utf8(read)?;

    Ok(srv_msg.to_string())
}

pub fn append(imap: &mut TcpStream, content: Email) -> Result<String> {
    let mut buffer: [u8; 6000] = [0; 6000];

    let ref_mail = match content {
        Email::Multipart => EMAIL1,
        Email::Basic => EMAIL2,
    };

    let append_cmd = format!("47 append inbox (\\Seen) {{{}}}\r\n", ref_mail.len());
    println!("append cmd: {}", append_cmd);
    imap.write(append_cmd.as_bytes())?;

    // wait for continuation
    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(read[0], b'+');

    // write our stuff
    imap.write(ref_mail)?;
    imap.write(&b"\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, Some(&b"47 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;

    Ok(srv_msg.to_string())
}

pub fn search(imap: &mut TcpStream, sk: SearchKind) -> Result<String> {
    let sk_str = match sk {
        SearchKind::Text(x) => format!("TEXT \"{}\"", x),
        SearchKind::ModSeq(x) => format!("MODSEQ {}", x),
    };
    imap.write(format!("55 SEARCH {}\r\n", sk_str).as_bytes())?;
    let mut buffer: [u8; 1500] = [0; 1500];
    let read = read_lines(imap, &mut buffer, Some(&b"55 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    Ok(srv_msg.to_string())
}

pub fn store(
    imap: &mut TcpStream,
    sel: Selection,
    flag: Flag,
    action: StoreAction,
    modifier: StoreMod,
) -> Result<String> {
    let mut buffer: [u8; 6000] = [0; 6000];

    let seq = match sel {
        Selection::FirstId => "1",
        Selection::SecondId => "2",
        Selection::All => "1:*",
    };

    let modif = match modifier {
        StoreMod::None => "".into(),
        StoreMod::UnchangedSince(val) => format!(" (UNCHANGEDSINCE {})", val),
    };

    let flags_str = match flag {
        Flag::Deleted => "(\\Deleted)",
        Flag::Important => "(\\Important)",
    };

    let action_str = match action {
        StoreAction::AddFlags => "+FLAGS",
        StoreAction::DelFlags => "-FLAGS",
        StoreAction::SetFlags => "FLAGS",
        StoreAction::AddFlagsSilent => "+FLAGS.SILENT",
        StoreAction::DelFlagsSilent => "-FLAGS.SILENT",
        StoreAction::SetFlagsSilent => "FLAGS.SILENT",
    };

    imap.write(format!("57 STORE {}{} {} {}\r\n", seq, modif, action_str, flags_str).as_bytes())?;
    let read = read_lines(imap, &mut buffer, Some(&b"57 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    Ok(srv_msg.to_string())
}

pub fn expunge(imap: &mut TcpStream) -> Result<()> {
    imap.write(&b"60 expunge\r\n"[..])?;
    let mut buffer: [u8; 1500] = [0; 1500];
    let _read = read_lines(imap, &mut buffer, Some(&b"60 OK EXPUNGE"[..]))?;

    Ok(())
}

pub fn uid_expunge(imap: &mut TcpStream, sel: Selection) -> Result<String> {
    use Selection::*;
    let mut buffer: [u8; 6000] = [0; 6000];
    let selstr = match sel {
        FirstId => "1",
        SecondId => "2",
        All => "1:*",
    };
    imap.write(format!("61 UID EXPUNGE {}\r\n", selstr).as_bytes())?;
    let read = read_lines(imap, &mut buffer, Some(&b"61 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    Ok(srv_msg.to_string())
}

pub fn rename_mailbox(imap: &mut TcpStream, from: Mailbox, to: Mailbox) -> Result<()> {
    assert!(matches!(from, Mailbox::Archive));
    assert!(matches!(to, Mailbox::Drafts));

    imap.write(&b"70 rename ArchiveCustom DraftsCustom\r\n"[..])?;
    let mut buffer: [u8; 1500] = [0; 1500];
    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(&read[..5], &b"70 OK"[..]);

    imap.write(&b"71 list \"\" *\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, Some(&b"71 OK LIST"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    assert!(!srv_msg.contains(" ArchiveCustom\r\n"));
    assert!(srv_msg.contains(" INBOX\r\n"));
    assert!(srv_msg.contains(" DraftsCustom\r\n"));

    Ok(())
}

pub fn delete_mailbox(imap: &mut TcpStream, mbx: Mailbox) -> Result<()> {
    let mbx_str = match mbx {
        Mailbox::Inbox => "INBOX",
        Mailbox::Archive => "ArchiveCustom",
        Mailbox::Drafts => "DraftsCustom",
    };
    let cmd = format!("80 delete {}\r\n", mbx_str);

    imap.write(cmd.as_bytes())?;
    let mut buffer: [u8; 1500] = [0; 1500];
    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(&read[..5], &b"80 OK"[..]);

    imap.write(&b"81 list \"\" *\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, Some(&b"81 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    assert!(srv_msg.contains(" INBOX\r\n"));
    assert!(!srv_msg.contains(format!(" {}\r\n", mbx_str).as_str()));

    Ok(())
}

pub fn close(imap: &mut TcpStream) -> Result<()> {
    imap.write(&b"60 close\r\n"[..])?;
    let mut buffer: [u8; 1500] = [0; 1500];
    let _read = read_lines(imap, &mut buffer, Some(&b"60 OK"[..]))?;

    Ok(())
}

pub fn r#move(imap: &mut TcpStream, selection: Selection, to: Mailbox) -> Result<String> {
    let mut buffer: [u8; 1500] = [0; 1500];
    assert!(matches!(to, Mailbox::Archive));
    assert!(matches!(selection, Selection::FirstId));

    imap.write(&b"35 move 1 ArchiveCustom\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, Some(&b"35 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    assert!(srv_msg.contains("* 1 EXPUNGE"));

    Ok(srv_msg.to_string())
}

pub fn enable(imap: &mut TcpStream, ask: Enable, done: Option<Enable>) -> Result<()> {
    let mut buffer: [u8; 6000] = [0; 6000];
    assert!(matches!(ask, Enable::Utf8Accept));

    imap.write(&b"36 enable UTF8=ACCEPT\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, Some(&b"36 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    match done {
        None => assert_eq!(srv_msg.lines().count(), 1),
        Some(Enable::Utf8Accept) => {
            assert_eq!(srv_msg.lines().count(), 2);
            assert!(srv_msg.contains("* ENABLED UTF8=ACCEPT"));
        }
        _ => unimplemented!(),
    }

    Ok(())
}

pub fn start_idle(imap: &mut TcpStream) -> Result<()> {
    let mut buffer: [u8; 1500] = [0; 1500];
    imap.write(&b"98 IDLE\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(read[0], b'+');
    Ok(())
}

pub fn stop_idle(imap: &mut TcpStream) -> Result<String> {
    let mut buffer: [u8; 16536] = [0; 16536];
    imap.write(&b"DONE\r\n"[..])?;
    let read = read_lines(imap, &mut buffer, Some(&b"98 OK"[..]))?;
    let srv_msg = std::str::from_utf8(read)?;
    Ok(srv_msg.to_string())
}

pub fn logout(imap: &mut TcpStream) -> Result<()> {
    imap.write(&b"99 logout\r\n"[..])?;
    let mut buffer: [u8; 1500] = [0; 1500];
    let read = read_lines(imap, &mut buffer, None)?;
    assert_eq!(&read[..5], &b"* BYE"[..]);
    Ok(())
}