-- keep-citations.lua
-- Replace citations with a placeholder and eat any preceding space.
local PH = "[citation]"

-- Pandoc-native citations (if the reader produced Cite nodes)
function Cite(el) return pandoc.Str(PH) end

-- Raw LaTeX \cite-like macros (when not parsed as Cite)
function RawInline(el)
    if el.format and el.format:match("tex") and el.text:match("\\%a-*cite%*?") then
        return pandoc.Str(PH)
    end
end

-- Remove a single leading Space before our placeholder
local function squash_spaces(inlines)
    local out = {}
    local i = 1
    while i <= #inlines do
        local cur = inlines[i]
        local nxt = inlines[i + 1]
        if cur and cur.t == "Space" and nxt and nxt.t == "Str" and nxt.text ==
            PH then
            table.insert(out, nxt)
            i = i + 2
        else
            table.insert(out, cur)
            i = i + 1
        end
    end
    return out
end

function Para(el)
    el.content = squash_spaces(el.content)
    return el
end

function Plain(el)
    el.content = squash_spaces(el.content)
    return el
end