vim9script

# Vim indent file
# Language: gdscript (Godot game engine)
# Maintainer: Maxim Kim <habamax@gmail.com>
# Based on python indent file.

if exists("b:did_indent")
    finish
endif
b:did_indent = 1

var undo_opts = "setl indentexpr< indentkeys< lisp< autoindent<"

if exists('b:undo_indent')
    b:undo_indent ..= "|" .. undo_opts
else
    b:undo_indent = undo_opts
endif

setlocal nolisp
setlocal autoindent
setlocal indentexpr=GDScriptIndent()
setlocal indentkeys+=<:>,=elif,=except


def GDScriptIndent(): number
    # If this line is explicitly joined: If the previous line was also joined,
    # line it up with that one, otherwise add two 'shiftwidth'
    if getline(v:lnum - 1) =~ '\\$'
        if v:lnum > 1 && getline(v:lnum - 2) =~ '\\$'
            return indent(v:lnum - 1)
        endif
        return indent(v:lnum - 1) + (shiftwidth() * 2)
    endif

    # If the start of the line is in a string don't change the indent.
    if has('syntax_items') && synIDattr(synID(v:lnum, 1, 1), "name") =~ "String$"
        return -1
    endif

    # Search backwards for the previous non-empty line.
    var plnum = prevnonblank(v:lnum - 1)

    if plnum == 0
        # This is the first non-empty line, use zero indent.
        return 0
    endif

    var plindent = indent(plnum)
    var plnumstart = plnum

    # Get the line and remove a trailing comment.
    # Use syntax highlighting attributes when possible.
    var pline = getline(plnum)
    var pline_len = strlen(pline)
    if has('syntax_items')
        # If the last character in the line is a comment, do a binary search for
        # the start of the comment.  synID() is slow, a linear search would take
        # too long on a long line.
        if synIDattr(synID(plnum, pline_len, 1), "name") =~ "\\(Comment\\|Todo\\)$"
            var min = 1
            var max = pline_len
            while min < max
                var col = (min + max) / 2
                if synIDattr(synID(plnum, col, 1), "name") =~ "\\(Comment\\|Todo\\)$"
                    max = col
                else
                    min = col + 1
                endif
            endwhile
            pline = strpart(pline, 0, min - 1)
        endif
    else
        var col = 0
        while col < pline_len
            if pline[col] == '#'
                pline = strpart(pline, 0, col)
                break
            endif
            col = col + 1
        endwhile
    endif


    # When "inside" parenthesis: If at the first line below the parenthesis add
    # one 'shiftwidth' ("inside" is simplified and not really checked)
    # my_var = (
    #     a
    #     + b
    #     + c
    # )
    if pline =~ '[({\[]\s*$'
        return indent(plnum) + shiftwidth()
    endif


    # If the previous line ended with a colon, indent this line
    if pline =~ ':\s*$'
        return plindent + shiftwidth()
    endif

    # If the previous line was a stop-execution statement...
    if getline(plnum) =~ '^\s*\(break\|continue\|raise\|return\|pass\)\>'
        # See if the user has already dedented
        if indent(v:lnum) > indent(plnum) - shiftwidth()
            # If not, recommend one dedent
            return indent(plnum) - shiftwidth()
        endif
        # Otherwise, trust the user
        return -1
    endif

    # If the current line begins with a keyword that lines up with "try"
    if getline(v:lnum) =~ '^\s*\(except\|finally\)\>'
        var lnum = v:lnum - 1
        while lnum >= 1
            if getline(lnum) =~ '^\s*\(try\|except\)\>'
                var ind = indent(lnum)
                if ind >= indent(v:lnum)
                    return -1   # indent is already less than this
                endif
                return ind      # line up with previous try or except
            endif
            lnum = lnum - 1
        endwhile
        return -1               # no matching "try"!
    endif


    # If the current line begins with a header keyword, dedent
    if getline(v:lnum) =~ '^\s*\(elif\|else\)\>'

        # Unless the previous line was a one-liner
        if getline(plnumstart) =~ '^\s*\(for\|if\|try\)\>'
            return plindent
        endif

        # Or the user has already dedented
        if indent(v:lnum) <= plindent - shiftwidth()
            return -1
        endif

        return plindent - shiftwidth()
    endif

    return -1
enddef