colabbd/adapters/vim/collab.vim

if !has('vim9script') || v:version < 900
    finish
endif

vim9script

# collab.vim - collaborative editing adapter for collabd
# requires: bun, collabd daemon running

hlset([{
    name: 'PeerCursor',
    ctermbg: 'yellow',
    ctermfg: 'black',
    guibg: 'yellow',
    guifg: 'black'
}])

var bridge_job: job = null_job
var bridge_channel: channel = null_channel
var connected = false
var ready = false
var room = ""
var suppressing = false
var peer_match_ids: dict<number> = {}

# path to bridge script (adjust as needed)
const bridge_script = expand('<sfile>:p:h') .. '/bridge.ts'

def Send(msg: dict<any>): void
    if bridge_channel != null_channel
        ch_sendraw(bridge_channel, json_encode(msg) .. "\n")
    endif
enddef

def OnOutput(ch: channel, msg: string): void
    if msg->empty()
        return
    endif
    var data: dict<any>
    try
        data = json_decode(msg)
    catch
        return
    endtry

    if data.type == 'ready'
        ready = true
    elseif data.type == 'connected'
        connected = true
        echom $'[collab] connected to room: {data.room}'
    elseif data.type == 'disconnected'
        connected = false
        echom '[collab] disconnected'
    elseif data.type == 'content'
        ApplyRemoteContent(data.text)
    elseif data.type == 'peers'
        echom $'[collab] peers: {data.count}'
    elseif data.type == 'cursor'
        ShowPeerCursor(data.data)
    elseif data.type == 'error'
        echoerr '[collab] ' .. data.message
    endif
enddef

def ApplyRemoteContent(content: string): void
    if suppressing
        return
    endif
    suppressing = true
    var lines = content->split("\n", true)
    var view = winsaveview()
    silent! :%delete _
    setline(1, lines)
    winrestview(view)
    suppressing = false
enddef

def SendBuffer(): void
    if !connected || suppressing
        return
    endif
    var lines = getline(1, '$')
    var content = lines->join("\n")
    Send({type: 'content', text: content})
enddef

def SendCursor(): void
    if !connected
        return
    endif
    const pos = getpos('.')
    # pos is [bufnum, line, col, off] - line/col are 1-indexed
    Send({type: 'cursor', line: pos[1] - 1, col: pos[2] - 1})
enddef

def ShowPeerCursor(data: dict<any>): void
    const client_id = string(data.clientId)

    # Clear previous highlight for this peer
    if has_key(peer_match_ids, client_id)
        silent! matchdelete(peer_match_ids[client_id])
    endif

    # Highlight the cursor position (line, col are 0-indexed from bridge)
    const line_nr = data.line + 1
    const col_nr = data.col + 1

    # Create a 1-char highlight at cursor position
    const pattern = $'\%{line_nr}l\%{col_nr}c.'
    peer_match_ids[client_id] = matchadd('PeerCursor', pattern, 10)
enddef

def ClearPeerCursors(): void
    for id in values(peer_match_ids)
        silent! matchdelete(id)
    endfor
    peer_match_ids = {}
enddef

export def Connect(room_name: string): void
    if bridge_job != null_job
        Disconnect()
    endif

    room = room_name
    ready = false
    bridge_job = job_start(['bun', 'run', bridge_script], {
        mode: 'nl',
        out_cb: OnOutput,
        err_io: 'null'
    })
    bridge_channel = job_getchannel(bridge_job)

    # wait for bridge ready signal
    var timeout = 50
    while !ready && timeout > 0
        sleep 10m
        timeout -= 1
    endwhile

    if !ready
        echoerr '[collab] bridge failed to start'
        Disconnect()
        return
    endif

    Send({type: 'connect', room: room_name})

    # set up autocmds to send changes
    autocmd_add([
        {
            group: 'CollabVim',
            event: ['TextChanged', 'TextChangedI'],
            pattern: '*',
            cmd: 'SendBuffer()'
        },
        {
            group: 'CollabVim',
            event: ['CursorMoved', 'CursorMovedI'],
            bufnr: bufnr(),
            cmd: 'SendCursor()'
        }
    ])
enddef

export def Disconnect(): void
    if bridge_job != null_job
        Send({type: 'disconnect'})
        job_stop(bridge_job)
        bridge_job = null_job
        bridge_channel = null_channel
    endif
    ClearPeerCursors()
    connected = false
    ready = false
    room = ""
    autocmd_delete([{group: 'CollabVim'}])
    echom '[collab] disconnected'
enddef

export def Status(): void
    if connected
        echom $'[collab] connected to room: {room}'
    else
        echom '[collab] not connected'
    endif
enddef

# commands
command! -nargs=1 CollabJoin call Connect(<q-args>)
command! CollabLeave call Disconnect()
command! CollabStatus call Status()