#!/usr/bin/env texlua
--------------------------------------------------------------------------------
--         FILE:  rst_helpers.lua
--        USAGE:  ./rst_helpers.lua 
--  DESCRIPTION:  Complement to the reStructuredText parser
--       AUTHOR:  Philipp Gesang (Phg), <megas.kapaneus@gmail.com>
--      VERSION:  1.0
--      CREATED:  07/09/10 01:03:08 CEST
--------------------------------------------------------------------------------
--

local utf = unicode.utf8
local P, R, S, V, match 
    = lpeg.P, lpeg.R, lpeg.S, lpeg.V, lpeg.match

local C, Carg, Cb, Cc, Cg, Cmt, Cp, Cs, Ct 
    = lpeg.C, lpeg.Carg, lpeg.Cb, lpeg.Cc, lpeg.Cg, lpeg.Cmt, lpeg.Cp, lpeg.Cs, lpeg.Ct

local helpers = {}
helpers.table = {}
helpers.cell  = {}

local patterns  = {}

do
    local p = patterns
    p.dash   = P"-"
    p.equals = P"="
    p.plus   = P"+"
    p.bar    = P"|"
    p.eol    = P"\n"
    p.last   = -P(1)

    p.celldelim   = p.bar + p.plus
    p.cellcontent = (1 - p.celldelim)
    p.cell        = p.celldelim * C((1 - p.celldelim)^1) * #p.celldelim
    p.cell_line   = p.plus * p.dash^1 * #p.plus
    p.dashesonly  = p.dash^1 * p.last

    p.cells = P{
        [1] = "cells",
        cells = p.celldelim 
              * (C(V"in_cell")
               * (V"matchwidth" * C(V"in_cell")) ^1),

        in_cell = p.cellcontent^1
                + (p.dash - p.cellcontent)^1,

        matchwidth = Cmt(C(p.celldelim) * Carg(1), function(s,i,del, layout)
                         --print("~~~~~~~~~~~~~~ NEXT MATCH ~~~~~~~~~~~~~~")
                         local pos = 1
                         local lw = layout.widths
                         for n=1, #lw do
                             pos = pos + lw[n] + 1
                             --print(">",pos,i-1,i-1==pos)
                             if (i - 1) == pos then return true end
                         end
                         return false
                     end),
    }

    p.sep_line = p.plus * (p.dash^1   * p.plus)^1 * p.last
    p.sep_head = p.plus * (p.equals^1 * p.plus)^1 * p.last

    p.sep_part = ((1 - p.cell_line)^0 * p.cell_line) - p.sep_line

    p.new_row = p.sep_line + p.sep_head + p.sep_part

    p.whitespace = S" \t\v\r\n"^1
    p.strip = p.whitespace^0 * C((1 - (p.whitespace * p.last))^1) * p.whitespace^0 * p.last
end

function helpers.cell.create(raw, n_row, n_col, parent, variant)
    local p = patterns
    local cell = {}
    cell.stripped = raw and p.strip:match(raw) or ""
    cell.content  = raw
    cell.width    = raw and utf.len(raw) or 0
    cell.bytes    = raw and #raw or 0
    cell.variant  = "normal" -- [normal|separator|y_continue|x_continue]
    cell.pos      = {}
    cell.pos.x    = n_col
    cell.pos.y    = n_row
    cell.span     = {}
    cell.span.x   = 1
    cell.span.y   = 1
    cell.parent   = parent
    return cell
end

function helpers.cell.get_x_span(content, layout, init)
    --print(#content,">"..content.."<")
    --print(layout.widths[init],">"..layout.slices[init].."<")
    local acc = 0
    local lw = layout.widths
    for n=init, #lw do
        acc = acc + lw[n] + 1
        --print(n, layout.slices[n], acc)
        if utf.len(content) + 1 == acc then 
            return n - init
        end
    end
    return false
end


-- Extending a cell by 1 cell horizontally.
function helpers.cell.add_x (cell)
    cell.span.x = cell.span.x + 1
end


local function set_layout (line)
    local p = patterns
    local layout = {}
    local slice = Ct((p.plus * C(p.dash^1) * #p.plus)^1)

    layout.widths = {}
    layout.slices = {}
    for n, elm in ipairs(slice:match(line)) do
        layout.widths[n] = #elm
        layout.slices[n] =  elm
    end
    return layout
end

--function helpers.table.create(raw)
    --local self = {}
    --self.rows = {}

    --local p = patterns

    --self.resolve_parent = function(row, col)
        --print(row, col)
        --local cell = self.rows[row][col]
        --local par_row, par_col
        --if cell.parent then
            --par_row, par_col = self.resolve_parent(cell.parent.y, cell.parent.x)
        --else
            --return par_row, par_col
        --end
    --end
    
    --self.__init = function()
        --local hc = helpers.cell
        --self.layout = set_layout(raw[1])
        --local rowcount = 0

        -- first get the correct horizontal spans
        --local next_is_new_row = true
        --for n, line in ipairs(raw) do
            -- caching the test results
            --local sepline = p.sep_line:match(line)
            --local sephead = p.sep_head:match(line)
            --local seppart = p.sep_part:match(line)
            --local newrow  = sepline or sephead or seppart

            --if newrow and n > 1 then
                --if sephead then
                    --self.has_head = true
                --end
                --rowcount = rowcount + 1
            --end

            --if not (sepline  or
                    --sephead) then
                --local row = {}
                --row.newrow = (newrow or next_is_new_row) and true or false
                --next_is_new_row = false
                --local sl = self.layout
                --local splitted = {p.cells:match(line, 1, sl)}
                --local pos_layout, pos_line = 1, 1
                --local last = nil
                --local ignore = {}
                --ignore.n, ignore.parent = 0, nil
                --while pos_layout <= #sl.slices do
                    --local splitpos = splitted[pos_line]
                    --local splitpos = splitted[pos_layout]
                    --local width_layout = sl.widths[pos_layout]
                    --local span = 1
                    --local this
                    --if ignore.n > 0 then
                        --ignore.n = ignore.n - 1
                        --this = hc.create(false, n, pos_layout, true)
                        --row[pos_layout] = this
                        --this.parent = ignore.parent
                    --else
                        --local width_cell   = utf.len(splitpos)
                        --if width_cell > width_layout then
                            --print(splitpos, width_cell, sl.slices[pos_layout], width_layout)
                            -- check the horizontal span
                            --span = span + hc.get_x_span(splitpos, sl, pos_layout)
                        --end
                        --pos_line = pos_line + span
                        --this = hc.create(splitpos, n, pos_layout, false)
                        --if p.dashesonly:match(splitpos) then
                            --this.variant = "separator"
                        --end
                        --this.span.x = span
                        --last = this
                        --row[pos_layout] = this
                        --ignore.n = span - 1
                        --ignore.parent = ignore.n > 0 and { y = rowcount, x = pos_layout } or nil
                    --end
                    --pos_layout = pos_layout + 1
                    --print(">",this.pos.y,this.pos.x,this.span.y,this.span.x)
                    --if this.span.y > 1 then
                        --print(">"..this.content.."<")
                    --end
                --end
                --self.rows[#self.rows+1] = row
                --print(#self.rows.."<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<")
                --for i,j in ipairs(row) do print(i,j.content) end
                --print(row.newrow)
            --else -- separator
                --next_is_new_row = true

            --end
            --print(string.format("[t-%2s,%2s]> %s", n, m, cell))
        --end
        --print("rc = "..rowcount, "nr = "..#self.rows)
        --self.rowcount = rowcount

        --if self.rowcount < #self.rows then -- some cells span vertically
            --local has_partsep = function(row)
                --for n, cell in ipairs(row) do
                    --if cell.variant == "separator" then
                        --return true
                    --end
                --end
                --return false
            --end

            --local dont_do_next = false
            --for nr,row in ipairs(self.rows) do
                --local ps = has_partsep(row)

                --row.ignore = ps and true or false
                --if ps then
                    --self.rows[nr+1].newrow = true
                --end
                --if (not row.newrow or ps) and not dont_do_next then
                    --print(">>>>>>>>>> NEXT <<<<<<<<<<<<")
                    --print(row.newrow and has_partsep(row))
                    -- continues last row either fully or partially
                    --for nc, cell in ipairs(row) do
                        --print(nr, nc, cell.content)
                        --if cell.content == false then
                            -- empty cell
                        --elseif cell.variant ~= "separator" then
                            --local par_row, par_col
                            --if cell.parent then
                                --par_row, par_col = self.resolve_parent(cell.parent.y, cell.parent.x)
                                --print("old parent: ", par_row, par_col)
                            --else -- no previous span, setting parent to preceding row
                                --par_row, par_col = nr -1, nc
                                --print("new parent: ", par_row, par_col)
                            --end

                            --print (nr, nc, cell.content, cell.parent, par_row, par_col)
                            --local parent = self.rows[par_row][par_col]
                            --parent.span.y   = parent.span.y + 1
                            --parent.content  = parent.content .. cell.content
                            --parent.stripped = parent.stripped .. " " .. cell.stripped

                            --if ps then
                                --local successor  = self.rows[nr+1][nc]
                                --successor.parent = { x = par_col, y = par_row }
                                --parent.span.y    = parent.span.y + 1
                                --parent.content   = parent.content .. successor.content
                                --parent.stripped  = parent.stripped .. " " .. successor.stripped
                                --dont_do_next = true
                            --else
                                --dont_do_next = false
                            --end
                            --print(cell.content, parent.content)
                            --add_y(cell)
                        --end
                    --end
                --elseif dont_do_next then
                    --row.ignore = true
                    --dont_do_next = false
                --end
            --end
        --end -- vertical span handler
    --end -- end __init

    --self.__init()
    --return self
--end
                

function helpers.table.create(raw)
    local self = {}
    self.rows = {}
    self.layout = set_layout(raw[1])

    local p = patterns

    self.resolve_parent = function(row, col, array)
        local array = array or self.rows
        local cell = array[row][col]
        local par_row, par_col = row, col
        if cell.parent then
            par_row, par_col = self.resolve_parent(cell.parent.y, cell.parent.x)
        end
        return par_row, par_col
    end

    self.__init = function()
        local hc = helpers.cell
        local rowcount = 0
        local selflayout = self.layout
        for nr, row in ipairs(raw) do
            self.rows[nr] = {}
            local this_row = self.rows[nr]
            this_row.sepline = p.sep_line:match(row)
            this_row.sephead = p.sep_head:match(row)
            this_row.seppart = p.sep_part:match(row)
            if this_row.sephead then
                self.has_head = true
            end

            --if not this_row.sepline and not this_row.sephead then
                --print("new row" , row)
                local splitted = { p.cells:match(row, 1, selflayout) }
                local pos_layout, pos_row = 1, 1
                local make_empty = {}
                make_empty.n, make_empty.parent = 0, nil

                while pos_layout <= #selflayout.widths do
                    local splitpos = splitted[pos_layout]
                    local layoutwidth = selflayout.widths[pos_layout]
                    local span = 1
                    local this

                    if make_empty.n > 0 then
                        --print(make_empty.n, make_empty.parent)
                        make_empty.n = make_empty.n - 1
                        this = hc.create("", nr, pos_layout, make_empty.parent)
                        this.parent  = make_empty.parent
                        p_row, p_col = self.resolve_parent(this.parent.y, this.parent.x)
                        --print(p_row, p_col)
                        local thisparent = self.rows[p_row][p_col]
                        --print(this.parent.y, this.parent.x,p_row,p_col)
                        --this.variant = "empty" --self.rows[p_row][p_col].variant
                        --if self.rows[p_row][p_col].variant == "separator" then
                        if this_row.sepline or this_row.sephead or
                           self.rows[p_row][p_col].variant == "separator" then
                            this.variant = "separator"
                        else
                            this.variant = "empty1"
                        end
                        --this.variant = self.rows[p_row][p_col].variant
                    else
                        local cellwidth = utf.len(splitpos)
                        if cellwidth > layoutwidth then
                            span = span + hc.get_x_span(splitpos, selflayout, pos_layout)
                        end
                        pos_row = pos_row + span
                        this = hc.create(splitpos, nr, pos_layout, nil)
                        --print("this parent: ",this.parent)
                        if p.dashesonly:match(splitpos) or
                           this_row.sepline or this_row.sephead then
                            this.variant = "separator"
                        end
                        this.span.x = span
                        make_empty.n = span - 1
                        make_empty.parent = span > 1 and { y = nr, x = pos_layout } or nil
                        --print(this.content, make_empty.parent.y, make_empty.parent.x)
                    end

                    this_row[pos_layout] = this
                    pos_layout = pos_layout + 1
                end -- while
            --end -- if
        end -- for loop over rows

        --for i, j in ipairs(self.rows) do
            --print(i, #j)
            --if #j > 0 and j[3].parent then
                --print(j[3].content, j[3].span.x, j[3].parent.y, j[3].parent.x, j[3].variant)
            --end
        --end
        local oldrows = self.rows
        --local newrows = {}
        local newrows = oldrows
        for nc, width in ipairs(selflayout.widths) do
            -- this is gonna be extremely slow but at least it's readable
            local newrow
            --print("next columnt <-----------------------------")
            local currentrow = 1
            for nr, row in ipairs(newrows) do
                --newrows[nr] = newrows[nr] or {}
                local cell = row[nc]
                io.write(string.format("nc: %s, nr:%2s | %9s | ", nc, nr,cell.variant))
                if  row.sepline or row.sephead
                    or p.dashesonly:match(cell.content)
                    or cell.variant == "separator" then -- separator; skipping and beginning new row
                    
                    --newrows[currentrow] = cell
                    newrows[nr][nc] = cell
                    currentrow = currentrow + 1
                    newrow = true
                    io.write(string.format("new >%24s< ", cell.stripped))
                    if cell.parent then io.write("parent |") else io.write("no par |") end
                else
                    io.write(string.format("old >%24s< ", cell.stripped))
                    if cell.parent then io.write("parent |") else io.write("no par |") end
                    if newrow then
                        --newrows[currentrow] = cell
                        newrows[nr][nc] = cell
                        currentrow = currentrow + 1
                    else -- continuing parent

                        local par_row, par_col
                        local parent
                        if cell.parent then
                            --io.write(string.format(" use %s,%2s | ", cell.parent.x, cell.parent.y))
                            par_row, par_col = self.resolve_parent(cell.parent.y, cell.parent.x, newrows)
                            io.write(string.format(" use %s,%2s | ", par_col, par_row))
                        else -- Using vertical predecessor.
                            par_row, par_col = self.resolve_parent(nr-1,nc, newrows)
                            io.write(string.format(" new %s,%2s | ", par_col, par_row))
                        end
                        parent = newrows[par_row][par_col]

                        if newrows[nr].seppart then
                            io.write("span++")
                            parent.span.y   = parent.span.y + 1
                        end

                        --print(#newrows, par_row)
                        --if cell.variant ~= "empty1" then
                            -- Cells of type empty1 already have their content
                            -- delegated onto their respective horizontal parent.
                            parent.content  = parent.content  .. cell.content
                            parent.stripped = parent.stripped .. " " .. cell.stripped
                            cell.variant = "empty2"
                        --end
                        cell.parent  = { x = par_col, y = par_row }
                        --this = hc.create("", nr, nc, { x = par_col, y = par_row }, "empty2")
                        --this.variant = "empty2"
                        --cell = hc.create("", nr, nc, { x = par_col, y = par_row }, "empty2")
                        --newrows[nr][nc] = this
                    end
                    newrow = false
                end
                io.write("\n")
                newrows[nr][nc] = cell
            end -- for loop over rows
        end -- for loop over columns
        --self.rows = oldrows
        self.rows = newrows
    end

    self.__init()


    self.__draw_debug = function()
        for nr, row in ipairs(self.rows) do
            for nc, cell in ipairs(row) do
                local field = cell.variant:sub(1,7)
                if cell.parent then
                    field = field .. string.format(" %s,%2s",cell.parent.x, cell.parent.y)
                end
                io.write(string.format("%12s | ", field))
                --io.write(string.format("%10s | ",(cell.parent and "true" or "false")))
            end
            io.write("\n")
        end
    end

    self.__draw_debug()
    return self

end

return helpers