" internal state for whether it is enabled or not to avoid multiple subscriptions
let s:enabled = 0

let s:Markdown = vital#lsp#import('VS.Vim.Syntax.Markdown')
let s:MarkupContent = vital#lsp#import('VS.LSP.MarkupContent')
let s:FloatingWindow = vital#lsp#import('VS.Vim.Window.FloatingWindow')
let s:Window = vital#lsp#import('VS.Vim.Window')
let s:Buffer = vital#lsp#import('VS.Vim.Buffer')

function! lsp#internal#diagnostics#float#_enable() abort
    " don't even bother registering if the feature is disabled
    if !lsp#ui#vim#output#float_supported() | return | endif
    if !g:lsp_diagnostics_float_cursor | return | endif 

    if s:enabled | return | endif
    let s:enabled = 1

    let s:Dispose = lsp#callbag#pipe(
        \ lsp#callbag#merge(
        \   lsp#callbag#fromEvent(['CursorMoved', 'CursorHold']),
        \   lsp#callbag#pipe(
        \       lsp#callbag#fromEvent(['InsertEnter']),
        \       lsp#callbag#filter({_->!g:lsp_diagnostics_float_insert_mode_enabled}),
        \       lsp#callbag#tap({_->s:hide_float()}),
        \   )
        \ ),
        \ lsp#callbag#filter({_->g:lsp_diagnostics_float_cursor}),
        \ lsp#callbag#tap({_->s:hide_float()}),
        \ lsp#callbag#debounceTime(g:lsp_diagnostics_float_delay),
        \ lsp#callbag#map({_->{'bufnr': bufnr('%'), 'curpos': getcurpos()[0:2], 'changedtick': b:changedtick }}),
        \ lsp#callbag#distinctUntilChanged({a,b -> a['bufnr'] == b['bufnr'] && a['curpos'] == b['curpos'] && a['changedtick'] == b['changedtick']}),
        \ lsp#callbag#filter({_->mode() is# 'n'}),
        \ lsp#callbag#filter({_->getbufvar(bufnr('%'), '&buftype') !=# 'terminal' }),
        \ lsp#callbag#map({_->lsp#internal#diagnostics#under_cursor#get_diagnostic()}),
        \ lsp#callbag#subscribe({x->s:show_float(x)}),
        \ )
endfunction

function! lsp#internal#diagnostics#float#_disable() abort
    if !s:enabled | return | endif
    if exists('s:Dispose')
        call s:Dispose()
        unlet s:Dispose
    endif
    let s:enabled = 0
endfunction

function! s:show_float(diagnostic) abort
    let l:doc_win = s:get_doc_win()
    if !empty(a:diagnostic) && has_key(a:diagnostic, 'message')
        " Update contents. 
        call deletebufline(l:doc_win.get_bufnr(), 1, '$')
        call setbufline(l:doc_win.get_bufnr(), 1, lsp#utils#_split_by_eol(a:diagnostic['message']))

        " Compute size. 
        if g:lsp_float_max_width >= 1
            let l:maxwidth = g:lsp_float_max_width
        elseif g:lsp_float_max_width == 0
            let l:maxwidth = &columns
        else
            let l:maxwidth = float2nr(&columns * 0.4)
        endif
        let l:size = l:doc_win.get_size({
        \   'maxwidth': l:maxwidth,
        \   'maxheight': float2nr(&lines * 0.4),
        \ })

        " Compute position.
        let l:pos = s:compute_position(l:size)

        " Open window. 
        call l:doc_win.open({
        \   'row': l:pos[0],
        \   'col': l:pos[1],
        \   'width': l:size.width,
        \   'height': l:size.height,
        \   'border': v:true,
        \   'topline': 1,
        \ })
    else
        call s:hide_float()
    endif
endfunction

function! s:hide_float() abort
    let l:doc_win = s:get_doc_win()
    call l:doc_win.close()
endfunction

function! s:get_doc_win() abort
    if exists('s:doc_win')
        return s:doc_win
    endif

    let s:doc_win = s:FloatingWindow.new({
    \   'on_opened': { -> execute('doautocmd <nomodeline> User lsp_float_opened') },
    \   'on_closed': { -> execute('doautocmd <nomodeline> User lsp_float_closed') }
    \ })
    call s:doc_win.set_var('&wrap', 1)
    call s:doc_win.set_var('&conceallevel', 2)
    noautocmd silent let l:bufnr = s:Buffer.create()
    call s:doc_win.set_bufnr(l:bufnr)
    call setbufvar(s:doc_win.get_bufnr(), '&buftype', 'nofile')
    call setbufvar(s:doc_win.get_bufnr(), '&bufhidden', 'hide')
    call setbufvar(s:doc_win.get_bufnr(), '&buflisted', 0)
    call setbufvar(s:doc_win.get_bufnr(), '&swapfile', 0)
    return s:doc_win
endfunction

function! s:compute_position(size) abort
    let l:pos = screenpos(0, line('.'), col('.'))
    if l:pos.row == 0 && l:pos.col == 0
        let l:pos = {'curscol': screencol(), 'row': screenrow()}
    endif
    let l:pos = [l:pos.row + 1, l:pos.curscol + 1]
    if l:pos[0] + a:size.height > &lines
        let l:pos[0] = l:pos[0] - a:size.height - 3
    endif
    if l:pos[1] + a:size.width > &columns
        let l:pos[1] = l:pos[1] - a:size.width - 3
    endif
    return l:pos
endfunction