VERSION = "1.0.0"

local uutil = import("micro/util")
local utf8 = import("utf8")
local autoclose_pairs = {'""', "''", "``", "()", "{}", "[]"}
local conditional_autoclose_pairs = {"<>", "||"}
local auto_newline_pairs = {"()", "{}", "[]"}

function char_at(str, i)
    -- lua indexing is one off from go
    return uutil.RuneAt(str, i - 1)
end

function onRune(bp, r)
    for i = 1, #autoclose_pairs do
    	local pair_at_index = autoclose_pairs[i]
    
        if r == char_at(pair_at_index, 2) then
            local cur_line = bp.Buf:Line(bp.Cursor.Y)

            if char_at(cur_line, bp.Cursor.X + 1) == char_at(pair_at_index, 2) then
                bp:Backspace()
                bp:CursorRight()
                
                break
            end

            if bp.Cursor.X > 1 
               and (uutil.IsWordChar(char_at(cur_line, bp.Cursor.X - 1)) 
               or char_at(cur_line, bp.Cursor.X - 1) == char_at(pair_at_index, 1)) 
            then
                break
            end
        end
        
        if r == char_at(pair_at_index, 1) then
            local cur_line = bp.Buf:Line(bp.Cursor.Y)

            if bp.Cursor.X == uutil.CharacterCountInString(cur_line) 
               or not uutil.IsWordChar(char_at(cur_line, bp.Cursor.X + 1)) 
            then
                -- the '-' here is to derefence the pointer to bp.Cursor.Loc which is automatically made
                -- when converting go structs to lua
                -- It needs to be dereferenced because the function expects a non pointer struct
                bp.Buf:Insert(bp.Cursor.Loc * -1, char_at(pair_at_index, 2))
                bp:CursorLeft()
                
                break
            end
        end
    end
    
    return true
end

function preInsertNewline(bp)
    local cur_line = bp.Buf:Line(bp.Cursor.Y)
    local curRune = char_at(cur_line, bp.Cursor.X)
    local nextRune = char_at(cur_line, bp.Cursor.X + 1)
    local ws = uutil.GetLeadingWhitespace(cur_line)

    for i = 1, #auto_newline_pairs do
    	local autoNewLinePairsAtIndex = auto_newline_pairs[i]
    	
        if curRune == char_at(autoNewlinePairsAtIndex, 1) then
            if nextRune == char_at(autoNewlinePairsAtIndex, 2) then
                bp:InsertNewline()
                bp:InsertTab()
                bp.Buf:Insert(bp.Cursor.Loc * -1, "\n" .. ws)
                bp:StartOfLine()
                bp:CursorLeft()
                return false
            end
        end
    end

    return true
end

function preBackspace(bp)
    for i = 1, #autoclose_pairs do
    	local pair_at_index = autoclose_pairs[i]
        local cur_line = bp.Buf:Line(bp.Cursor.Y)
        
        if char_at(cur_line, bp.Cursor.X + 1) == char_at(pair_at_index, 2) 
           and char_at(cur_line, bp.Cursor.X) == char_at(pair_at_index, 1) 
        then
            bp:Delete()
        end
    end

    return true
end