" lawrencium.vim - A Mercurial wrapper
" Maintainer:   Ludovic Chabant <http://ludovic.chabant.com>
" Version:      0.1

" Globals {{{

if !exists('g:lawrencium_debug')
    let g:lawrencium_debug = 0
endif

if (exists('g:loaded_lawrencium') || &cp) && !g:lawrencium_debug
    finish
endif
let g:loaded_lawrencium = 1

if !exists('g:lawrencium_hg_executable')
    let g:lawrencium_hg_executable = 'hg'
endif

if !exists('g:lawrencium_trace')
    let g:lawrencium_trace = 0
endif

if g:lawrencium_debug
    echom "Loaded Lawrencium."
endif

" }}}

" Utility {{{

" Strips the ending slash in a path.
function! s:stripslash(path)
    return fnamemodify(a:path, ':s?[/\\]$??')
endfunction

" Normalizes the slashes in a path.
function! s:normalizepath(path)
    if exists('+shellslash') && &shellslash
        return substitute(a:path, '\\', '/', '')
    elseif has('win32')
        return substitute(a:path, '/', '\\', '')
    else
        return a:path
    endif
endfunction

" Prints a message if debug tracing is enabled.
function! s:trace(message)
   if g:lawrencium_trace 
       let l:message = "lawrencium: " . a:message
       echom l:message
   endif
endfunction

" Throw a Lawrencium exception message.
function! s:throw(message)
    let v:errmsg = "lawrencium: " . a:message
    throw v:errmsg
endfunction

" Finds the repository root given a path inside that repository.
" Throw an error if not repository is found.
function! s:find_repo_root(path)
    let l:path = s:stripslash(a:path)
    let l:previous_path = ""
    while l:path != l:previous_path
        if isdirectory(l:path . '/.hg/store')
            return simplify(fnamemodify(l:path, ':p'))
        endif
        let l:previous_path = l:path
        let l:path = fnamemodify(l:path, ':h')
    endwhile
    call s:throw("No Mercurial repository found above: " . a:path)
endfunction

" }}}

" Mercurial Repository {{{

" Let's define a Mercurial repo 'class' using prototype-based object-oriented
" programming.
"
" The prototype dictionary.
let s:HgRepo = {}

" Constructor
function! s:HgRepo.New(path) abort
    let l:newRepo = copy(self)
    let l:newRepo.root_dir = s:find_repo_root(a:path)
    call s:trace("Built new Mercurial repository object at : " . l:newRepo.root_dir)
    return l:newRepo
endfunction

" Gets a full path given a repo-relative path
function! s:HgRepo.GetFullPath(path) abort
    let l:root_dir = self.root_dir
    if a:path =~# '^[/\\]'
        let l:root_dir = s:stripslash(l:root_dir)
    endif
    return l:root_dir . a:path
endfunction

" Gets a list of files matching a root-relative pattern.
" If a flag is passed and is TRUE, a slash will be appended to all
" directories.
function! s:HgRepo.Glob(pattern, ...) abort
    let l:root_dir = self.root_dir
    if (a:pattern =~# '^[/\\]')
        let l:root_dir = s:stripslash(l:root_dir)
    endif
    let l:matches = split(glob(l:root_dir . a:pattern), '\n')
    if a:0 && a:1
        for l:idx in range(len(l:matches))
            if !filereadable(l:matches[l:idx])
                let l:matches[l:idx] = l:matches[l:idx] . '/'
            endif
        endfor
    endif
    let l:strip_len = len(l:root_dir)
    call map(l:matches, 'v:val[l:strip_len : -1]')
    return l:matches
endfunction

" Runs a Mercurial command in the repo
function! s:HgRepo.RunCommand(command, ...) abort
    let l:hg_command = g:lawrencium_hg_executable . ' --repository ' . shellescape(s:stripslash(self.root_dir))
    let l:hg_command = l:hg_command . ' ' . a:command . ' ' . join(a:000, ' ')
    call s:trace("Running Mercurial command: " . l:hg_command)
    return system(l:hg_command)
endfunction

" Repo cache map
let s:buffer_repos = {}

" Get a cached repo
function! s:hg_repo(...) abort
    " Use the given path, or the mercurial directory of the current buffer.
    if a:0 == 0
        if exists('b:mercurial_dir')
            let l:path = b:mercurial_dir
        else
            let l:path = s:find_repo_root(expand('%:p'))
        endif
    else
        let l:path = a:1
    endif
    " Find a cache repo instance, or make a new one.
    if has_key(s:buffer_repos, l:path)
        return get(s:buffer_repos, l:path)
    else
        let l:repo = s:HgRepo.New(l:path)
        let s:buffer_repos[l:path] = l:repo
        return l:repo
    endif
endfunction

" Sets up the current buffer with Lawrencium commands if it contains a file from a Mercurial repo.
" If the file is not in a Mercurial repo, just exit silently.
function! s:setup_buffer_commands() abort
    call s:trace("Scanning buffer '" . bufname('%') . "' for Lawrencium setup...")
    let l:do_setup = 1
    if exists('b:mercurial_dir')
        if b:mercurial_dir =~# '/^\s*$/'
            unlet b:mercurial_dir
        else
            let l:do_setup = 0
        endif
    endif
    try
        let l:repo = s:hg_repo()
    catch /^lawrencium\:/
        return
    endtry
    let b:mercurial_dir = l:repo.root_dir
    if exists('b:mercurial_dir') && l:do_setup
        call s:trace("Setting Mercurial commands for buffer '" . bufname('%'))
        call s:trace("  with repo : " . expand(b:mercurial_dir))
        silent doautocmd User Lawrencium
    endif
endfunction

augroup lawrencium_detect
    autocmd!
    autocmd BufNewFile,BufReadPost *     call s:setup_buffer_commands()
    autocmd VimEnter               *     if expand('<amatch>')==''|call s:setup_buffer_commands()|endif
augroup end

" }}}

" Commands {{{

let s:main_commands = []

function! s:AddMainCommand(command) abort
    let s:main_commands += [a:command]
endfunction

function! s:DefineMainCommands()
    for l:command in s:main_commands
        execute 'command! -buffer ' . l:command
    endfor
endfunction

augroup lawrencium_main
    autocmd!
    autocmd User Lawrencium call s:DefineMainCommands()
augroup end

" }}}

" HgExecute {{{

function! s:HgExecute(...) abort
    let l:repo = s:hg_repo()
    echo call(l:repo.RunCommand, a:000, l:repo)
endfunction

call s:AddMainCommand("-nargs=* Hg :execute s:HgExecute(<f-args>)")

" }}}

" HgStatus {{{

function! s:HgStatus() abort
    echo s:hg_repo().RunCommand('status')
endfunction

call s:AddMainCommand("HgStatus :execute s:HgStatus()")

" }}}

" Hgcd, Hglcd {{{

function! s:ListRepoDirs(ArgLead, CmdLine, CursorPos) abort
    let l:matches = s:hg_repo().Glob(a:ArgLead . '*/')
    call map(l:matches, 's:normalizepath(v:val)')
    return l:matches
endfunction

call s:AddMainCommand("-bang -nargs=? -complete=customlist,s:ListRepoDirs Hgcd :cd<bang> `=s:hg_repo().GetFullPath(<q-args>)`")
call s:AddMainCommand("-bang -nargs=? -complete=customlist,s:ListRepoDirs Hglcd :lcd<bang> `=s:hg_repo().GetFullPath(<q-args>)`")

" }}}

" Hgedit {{{

function! s:ListRepoFiles(ArgLead, CmdLine, CursorPos) abort
    let l:matches = s:hg_repo().Glob(a:ArgLead . '*', 1)
    call map(l:matches, 's:normalizepath(v:val)')
    return l:matches
endfunction

call s:AddMainCommand("-bang -nargs=? -complete=customlist,s:ListRepoFiles Hgedit :edit<bang> `=s:hg_repo().GetFullPath(<q-args>)`")

" }}}

" Autoload Functions {{{

" Prints a summary of the current repo (if any) that's appropriate for
" displaying on the status line.
function! lawrencium#statusline(...)
    if !exists('b:mercurial_dir')
        return ''
    endif
    let l:summary = s:hg_repo().RunCommand('summary')
    let l:parent_rev = matchstr(l:summary, 'parent\: \d+\:[0-9a-f]+')
    let l:branch = matchstr(l:summary, 'branch\: [\d\w\-_\.]+')
    return l:branch . ', ' . l:parent_rev
endfunction

" Rescans the current buffer for setting up Mercurial commands.
" Passing '1' as the parameter enables debug traces temporarily.
function! lawrencium#rescan(...)
    if exists('b:mercurial_dir')
        unlet b:mercurial_dir
    endif
    if a:0 && a:1
        let l:trace_backup = g:lawrencium_trace
        let g:lawrencium_trace = 1
    endif
    call s:setup_buffer_commands()
    if a:0 && a:1
        let g:lawrencium_trace = l:trace_backup
    endif
endfunction

" Enables/disables the debug trace.
function! lawrencium#debugtrace(...)
    let g:lawrencium_trace = (a:0 == 0 || (a:0 && a:1))
    echom "Lawrencium debug trace is now " . (g:lawrencium_trace ? "enabled." : "disabled.")
endfunction

" }}}