Module:VolDiff

Documentation for this module may be created at Module:VolDiff/doc

local p = {}

-- Helper function to parse chapter number from the chapter link
local function getChapterNumber(chapterLink)
    local fullMatch = mw.ustring.match(chapterLink, "%[%[(.-)%]%]")
    if fullMatch then
        local splitMatch = mw.text.split(fullMatch, "|")
        return splitMatch[1]
    end
    return nil
end

-- Helper function to extract content under a specific section header
local function extractSection(content, header)
    local pattern = header .. "(.-)(===)"
    local sectionContent = mw.ustring.match(content, pattern)
    if not sectionContent then
        pattern = header .. "(.-)$"
        sectionContent = mw.ustring.match(content, pattern)
    end
    return sectionContent
end

-- Helper function to capture the entire template, including nested braces
local function captureTemplate(content, templateName)
    local templateStart, templateEnd = mw.ustring.find(content, "{{%s*" .. templateName .. "%s*[|\n]")
    if not templateStart then
        return nil, nil, nil
    end

    local finalTemplate = {}
    table.insert(finalTemplate, mw.ustring.sub(content, templateStart, templateEnd))
    local i = templateEnd + 1
    local braceCount = 2  -- Account for the initial "{{"

    while i <= mw.ustring.len(content) do
        local char = mw.ustring.sub(content, i, i)
        table.insert(finalTemplate, char)

        if char == '{' then
            braceCount = braceCount + 1
        elseif char == '}' then
            braceCount = braceCount - 1
            if braceCount == 0 then
                break
            end
        end

        i = i + 1
    end

    return table.concat(finalTemplate), templateStart, i
end

-- Helper function to capture the entire Desc parameter
local function captureDescParameter(diff)
    local descStart, descEnd = mw.ustring.find(diff, "Desc%s*=%s*")
    if not descStart then
        return nil
    end
    local finalDesc = {}
    local i = descEnd + 1
    local braceCount = 0

    while i <= mw.ustring.len(diff) - 2 do -- Subtract 2 from length to remove the }} from Diff
        local char = mw.ustring.sub(diff, i, i)
        table.insert(finalDesc, char)

        if char == '{' or char == '[' then
            braceCount = braceCount + 1
        elseif char == '}' or char == ']' then
            if braceCount > 0 then
                braceCount = braceCount - 1
            else
                break
            end
        elseif char == '|' and braceCount == 0 then
            break
        end

        i = i + 1
    end
    return mw.text.trim(table.concat(finalDesc))
end

-- Function to find all Diff positions
local function findDiffPositions(content)
    local positions = {}
    local startPos = 1

    while true do
        local diffStart, diffEnd = mw.ustring.find(content, "{{%s*Diff%s*[|\n]", startPos)
        if not diffStart then
            break
        end
        table.insert(positions, {diffStart, diffEnd})
        startPos = diffEnd + 1
    end

    return positions
end

-- Main function to process the VolDiffs template
function p.main(frame)
    local args = frame:getParent().args
    local currentTitle = mw.title.getCurrentTitle().text
    local sourcePage = args[1]
    local sectionType = args[2] or "magazine"
    local sectionHeader = sectionType == "reprint" and "===Reprint Differences===" or "===Magazine Differences==="
    local result = ""

    if not sourcePage then
        return "Error: No source page specified."
    end

    -- Fetch the content from the specified source page
    local content = mw.title.new(sourcePage):getContent()
    if not content then
        return "Error: Could not fetch content from the specified source page."
    end

    -- Extract the section content
    local sectionContent = extractSection(content, sectionHeader)
    if not sectionContent then
        return "Error: No section found with header " .. sectionHeader
    end

    -- Extract the entire VolDiffs content using brace counting
    local volDiffsContent, _, _ = captureTemplate(sectionContent, "VolDiffs")
    if not volDiffsContent then
        return "Error: No VolDiffs found in the specified section."
    end

    -- Extract VolDiffs parameters
    local part = mw.ustring.match(volDiffsContent, "Part%s*=%s*([^|]+)") or ""
    local title = mw.ustring.match(volDiffsContent, "Title%s*=%s*([^|]+)") or ""
    local label1 = mw.ustring.match(volDiffsContent, "Label1%s*=%s*([^|]*)") or ""
    local label2 = mw.ustring.match(volDiffsContent, "Label2%s*=%s*([^|]*)") or ""

    -- Start the VolDiffs template
    result = result .. string.format('{{VolDiffs|Part=%s|Title=%s', part, title)
    if label1 ~= "" then result = result .. string.format('|Label1=%s', label1) end
    if label2 ~= "" then result = result .. string.format('|Label2=%s', label2) end
    result = result .. '|\n'

    -- Find all Diff positions
    local diffPositions = findDiffPositions(volDiffsContent)

    -- Process each Diff entry
    local hasDiffs = false
    local diffEntries = {}

    for _, pos in ipairs(diffPositions) do
        local diffContent, _, _ = captureTemplate(volDiffsContent:sub(pos[1]), "Diff")

        if diffContent then
            local diffPart = mw.ustring.match(diffContent, "Part%s*=%s*([^|]+)")
            local diffChapter = mw.ustring.match(diffContent, "Chapter%s*=%s*(%[%[.-%]%])")
            local diffPage = mw.ustring.match(diffContent, "Page%s*=%s*([^|]+)")
            local diffImage1 = mw.ustring.match(diffContent, "Image1%s*=%s*([^|]+)")
            local diffImage2 = mw.ustring.match(diffContent, "Image2%s*=%s*([^|]+)")
            local diffDesc = captureDescParameter(diffContent)
            local diffLabel1 = mw.ustring.match(diffContent, "Label1%s*=%s*([^|]*)") or ""
            local diffLabel2 = mw.ustring.match(diffContent, "Label2%s*=%s*([^|]*)") or ""

            if diffPart and diffChapter and diffPage and diffImage1 and diffImage2 and diffDesc then
                local chapterNumber = getChapterNumber(diffChapter)

                -- Check if the current page title matches the chapter number
                if chapterNumber and mw.ustring.match(currentTitle, chapterNumber) then
                    hasDiffs = true
                    table.insert(diffEntries, string.format('{{Diff|Part=%s|Chapter=%s|Page=%s|Image1=%s|Image2=%s|Desc=%s',
                        diffPart, diffChapter, diffPage, diffImage1, diffImage2, mw.text.trim(diffDesc)))

                    -- Add optional labels if they are present
                    if diffLabel1 ~= "" then table.insert(diffEntries, string.format('|Label1=%s', diffLabel1)) end
                    if diffLabel2 ~= "" then table.insert(diffEntries, string.format('|Label2=%s', diffLabel2)) end

                    table.insert(diffEntries, '}}\n')
                end
            end
        end
    end

    -- Concatenate all diff entries at once
    result = result .. table.concat(diffEntries)

    -- End the VolDiffs template or provide a message if no diffs are found
    if hasDiffs then
        result = result .. '}}'
    else
        result = "No differences found for this chapter."
    end

    return frame:preprocess(result)
end

return p