ICT:FinalContent - ASSET - LUA

-- Module:DigitalAssetID
local p = {}

local cargo = mw.ext.cargo

-- Helper: zero-pad sequence number
local function pad(num)
    return string.format("%04d", tonumber(num))
end

-- Main function: compute identifier
function p.generate(frame)
    local args = frame.args
    local chapterPage = args.chapter_id
    local placePage = args.place_id
    local orgPage = args.organisation_id

    -- 1. Enforce exclusivity
    if (placePage ~= "" and orgPage ~= "") then
        return mw.text.jsonEncode({
            error = "Select either a Place OR an Organisation, not both."
        })
    end

    if (placePage == "" and orgPage == "") then
        return mw.text.jsonEncode({
            error = "You must select a Place OR an Organisation."
        })
    end

    -- 2. Fetch Chapter code
    local chapterRes = cargo.query(
        "ResearchChapters",
        "code",
        { where = string.format("_pageName='%s'", chapterPage) }
    )

    if not chapterRes[1] then
        return mw.text.jsonEncode({ error = "Invalid chapter selected." })
    end

    local chapterCode = chapterRes[1].code

    -- 3. Fetch context code (Place or Organisation)
    local contextCode = nil
    local contextTable = nil
    local contextPage = nil

    if placePage ~= "" then
        contextTable = "Places"
        contextPage = placePage
    else
        contextTable = "Organisations"
        contextPage = orgPage
    end

    local ctxRes = cargo.query(
        contextTable,
        "code",
        { where = string.format("_pageName='%s'", contextPage) }
    )

    if not ctxRes[1] then
        return mw.text.jsonEncode({ error = "Invalid context selected." })
    end

    contextCode = ctxRes[1].code

    -- 4. Determine next sequence number
    local existing = cargo.query(
        "DigitalAssets",
        "sequence_number",
        {
            where = string.format(
                "chapter_id='%s' AND (place_id='%s' OR organisation_id='%s')",
                chapterPage, placePage, orgPage
            ),
            orderBy = "sequence_number DESC",
            limit = 1
        }
    )

    local nextSeq = 1
    if existing[1] and existing[1].sequence_number then
        nextSeq = tonumber(existing[1].sequence_number) + 1
    end

    -- 5. Format identifier
    local identifier = string.format(
        "%s-%s-%s",
        chapterCode,
        contextCode,
        pad(nextSeq)
    )

    -- 6. Return result
    return mw.text.jsonEncode({
        identifier = identifier,
        sequence_number = nextSeq
    })
end

return p