Editing Module:AuthorsDisplay

-- Module:AuthorsDisplay
-- Purpose: Display all authors linked to a Wikibase item via P2 (Has author),
--          along with each author's country from P14 (Has Country)
-- Usage: {{#invoke:AuthorsDisplay|main}}

local p = {}

--- Main function: Fetches authors from the current page's sitelinked Wikibase item
-- and renders them in a wiki table with their countries.
--
-- @function p.main
-- @param frame The Lua frame object (contains template arguments)
-- @return string A wiki table showing authors and their countries, or error message
function p.main(frame)
    
    -- Fetch the Wikibase entity linked to the current MediaWiki page
    -- mw.wikibase.getEntity() with no parameter gets the sitelinked item
    local entity = mw.wikibase.getEntity()
    
    -- Validate: Check if entity exists and has P2 (author) claims
    if not entity or not entity.claims or not entity.claims.P2 then
        return "<i>No authors found.</i>"
    end
    
    -- Extract all P2 (Has author) statements from the entity
    local authors = entity.claims.P2
    
    -- Initialize the wiki table with headers
    local output = '{| class="wikitable" style="border-collapse: collapse;"\n'
    output = output .. '|-\n! Author !! Country\n'
    
    -- Loop through each author claim in P2
    for _, claim in ipairs(authors) do
        
        -- Verify this claim is a valid wikibase-item with an actual value
        -- (not a "somevalue" or "novalue" placeholder)
        if claim.mainsnak.datatype == "wikibase-item" and claim.mainsnak.snaktype == "value" then
            
            -- Extract the item ID of the author (e.g., "Q5")
            local authorId = claim.mainsnak.datavalue.value.id
            
            -- Fetch the full Wikibase entity for this author
            local authorEntity = mw.wikibase.getEntity(authorId)
            
            -- Process this author only if the entity was successfully retrieved
            if authorEntity then
                
                -- Get the author's label (human-readable name)
                -- Falls back to the item ID if no label exists
                local authorLabel = authorEntity:getLabel() or authorId
                
                -- Initialize country as "Unknown" (default value)
                local country = "Unknown"
                
                -- Try to retrieve P14 (country) from the author's statements
                if authorEntity.claims and authorEntity.claims.P14 then
                    
                    -- Get the first P14 claim (in case there are multiple)
                    local countryClaim = authorEntity.claims.P14[1]
                    
                    -- Extract the country value only if it's a string datatype
                    if countryClaim and countryClaim.mainsnak.datatype == "string" then
                        country = countryClaim.mainsnak.datavalue.value
                    end
                end
                
                -- Append a new table row with author label and country
                output = output .. '|-\n| ' .. authorLabel .. ' || ' .. country .. '\n'
            end
        end
    end
    
    -- Close the wiki table
    output = output .. '|}\n'
    
    -- Return the formatted wiki table as a string
    return output
end

-- Return the module table containing the main function
return p