--[[
╔════════════════════════════════════════════════════════════════════════════╗
║ Module:P703 - Organism Display with Inline Citations                       ║
║                                                                            ║
║ Author: AdrianoRutz                                                        ║
║ License: CC0 / Public Domain                                               ║
║                                                                            ║
║ Description:                                                               ║
║   Displays organisms (P703 "found in taxon") with formatted citations      ║
║   extracted directly from Wikidata references. Zero external dependencies. ║
║                                                                            ║
║ Usage:                                                                     ║
║   {{#invoke:P703|main|qid=Q2079986|numval=5|sources=true}}                 ║
║                                                                            ║
║ Parameters:                                                                ║
║   - qid: Wikidata entity ID (defaults to current page)                     ║
║   - numval: Maximum organisms to display (default: 5)                      ║
║   - sources: Show inline citations (default: true)                         ║
╚════════════════════════════════════════════════════════════════════════════╝
--]]
local p = {}

--[[────────────────────────────────────────────────────────────────────────────
  SECTION 1: CONFIGURATION & INTERNATIONALIZATION
────────────────────────────────────────────────────────────────────────────]]
-- Localization strings - edit these for language-specific deployments
local i18n = {
    no_organism = "kein Organismus bekannt",
    including = "darunter",
    wd_label = "d", -- Label for Wikidata link
    separator = ", ", -- List separator
    organism = "Organismus", -- Singular form
    organisms = "Organismen" -- Plural form
}

-- Entity cache prevents redundant API calls for the same Wikidata item
local entityCache = {}

--[[────────────────────────────────────────────────────────────────────────────
  SECTION 2: CITATION ENGINE
  
  Extracts and formats bibliographic data from Wikidata references.
  Supports: authors, title, journal, volume, issue, pages, DOI, PMID, dates
────────────────────────────────────────────────────────────────────────────]]
--- Safely extracts a property value from a Wikidata entity
-- @param entity table The Wikidata entity object
-- @param prop string The property ID (e.g., "P1476")
-- @return string|nil The property value or nil if not found
local function getPropertyValue(entity, prop)
    local claims = entity.claims and entity.claims[prop]
    if not claims or not claims[1].mainsnak.datavalue then
        return nil
    end

    local datavalue = claims[1].mainsnak.datavalue.value

    -- Handle different datavalue types
    if type(datavalue) == "table" then
        return datavalue.text or datavalue.id or datavalue.time
    end

    return datavalue
end

--- Extracts and formats author list from Wikidata
-- @param entity table The source entity containing author claims
-- @param maxAuthors number Maximum authors to list before "et al."
-- @return string|nil Formatted author string or nil
local function getAuthors(entity, maxAuthors)
    maxAuthors = maxAuthors or 3

    local authorClaims = entity.claims and (entity.claims.P50 or entity.claims.P2093)
    if not authorClaims then
        return nil
    end

    local authors = {}
    for i, snak in ipairs(authorClaims) do
        if i > maxAuthors then
            table.insert(authors, "et al.")
            break
        end

        if snak.mainsnak.datavalue then
            local authorValue = snak.mainsnak.datavalue.value
            local authorId = (type(authorValue) == "table") and authorValue.id or authorValue
            table.insert(authors, mw.wikibase.getLabel(authorId) or authorId)
        end
    end

    return #authors > 0 and table.concat(authors, ", ") or nil
end

--- Generates formatted citation from Wikidata reference
-- @param frame table MediaWiki frame object (for extensionTag)
-- @param claim table The Wikidata claim containing references
-- @return string Formatted MediaWiki reference(s) or empty string
local function getCleanRef(frame, claim)
    if not claim.references then
        return ""
    end

    local refs = {}

    for _, ref in ipairs(claim.references) do
        local cite = {}
        local sourceQid = nil

        -- Extract source (P248 = "stated in")
        if ref.snaks and ref.snaks.P248 then
            sourceQid = ref.snaks.P248[1].datavalue.value.id
        end

        if sourceQid then
            -- Use cached entity if available to reduce API calls
            local srcEntity = entityCache[sourceQid] or mw.wikibase.getEntity(sourceQid)

            if srcEntity then
                entityCache[sourceQid] = srcEntity

                -- Extract bibliographic metadata
                cite.title = getPropertyValue(srcEntity, "P1476") or mw.wikibase.getLabel(sourceQid)
                cite.journal = mw.wikibase.getLabel(getPropertyValue(srcEntity, "P1433"))
                cite.vol = getPropertyValue(srcEntity, "P478")
                cite.issue = getPropertyValue(srcEntity, "P433")
                cite.pages = getPropertyValue(srcEntity, "P304")
                cite.doi = getPropertyValue(srcEntity, "P356")
                cite.pmid = getPropertyValue(srcEntity, "P698")
                cite.authors = getAuthors(srcEntity, 3)

                -- Extract publication year from date
                local rawDate = getPropertyValue(srcEntity, "P577")
                if type(rawDate) == "string" then
                    cite.date = rawDate:match("+?(%d%d%d%d)")
                end
            end
        elseif ref.snaks and ref.snaks.P854 then
            -- Fallback to URL reference (P854 = "reference URL")
            cite.url = ref.snaks.P854[1].datavalue.value
        end

        -- Assemble citation in bibliographic format
        local parts = {}

        -- Authors
        if cite.authors and cite.authors ~= "" then
            table.insert(parts, cite.authors .. ".")
        end

        -- Title (with optional URL)
        if cite.title then
            local titleStr = cite.url and ("[" .. cite.url .. ' "' .. cite.title .. '"]') or ('"' .. cite.title .. '"')
            table.insert(parts, titleStr .. ".")
        elseif cite.url then
            table.insert(parts, "[" .. cite.url .. " Wikidata Source].")
        end

        -- Journal information
        if cite.journal then
            local journalStr = "''" .. cite.journal .. "''"

            if cite.vol then
                journalStr = journalStr .. " '''" .. cite.vol .. "'''"
            end
            if cite.issue then
                journalStr = journalStr .. " (" .. cite.issue .. ")"
            end
            if cite.pages then
                journalStr = journalStr .. ": pp. " .. cite.pages
            end

            table.insert(parts, journalStr .. ".")
        end

        -- Publication date
        if cite.date then
            table.insert(parts, "(" .. cite.date .. ").")
        end

        -- Identifiers
        if cite.doi then
            table.insert(parts, "[[doi:" .. cite.doi .. "|doi:" .. cite.doi .. "]].")
        end
        if cite.pmid then
            table.insert(parts, "[[pmid:" .. cite.pmid .. "|pmid:" .. cite.pmid .. "]].")
        end

        -- Create MediaWiki reference tag
        if #parts > 0 then
           table.insert(refs, frame:extensionTag("ref", table.concat(parts, " ")))
        end
    end
    
    -- Using a span with vertical-align: super ensures it matches the ref marker height exactly
    return table.concat(refs, '<span style="vertical-align: 0.9em; font-size: 0.7em;">,</span>')
end

--[[────────────────────────────────────────────────────────────────────────────
  SECTION 3: DYNAMIC INTERWIKI LINKING
  
  Creates smart links that:
  1. Link to local wiki article if it exists
  2. Link to another language wiki with lang code if no local article
  3. Link to Wikidata as fallback
────────────────────────────────────────────────────────────────────────────]]
--- Generates optimal interwiki link for a Wikidata item
-- @param itemId string The Wikidata Q-identifier
-- @return string Formatted wikilink with fallback to interwiki or Wikidata
local function getDynamicLink(itemId)
    local label = mw.wikibase.getLabel(itemId) or itemId
    local entity = mw.wikibase.getEntity(itemId)
    local sitelinks = (entity and entity.sitelinks) or {}

    -- Priority 1: Local wiki article
    local currentWiki = mw.language.getContentLanguage():getCode() .. "wiki"
    if sitelinks[currentWiki] then
        return "[[" .. sitelinks[currentWiki].title .. "|" .. label .. "]]"
    end

    -- Priority 2: First available interwiki link (excluding Wikidata/Commons)
    for wiki, data in pairs(sitelinks) do
        if wiki:match("wiki$") and wiki ~= "wikidatawiki" and wiki ~= "commonswiki" then
            local langCode = wiki:gsub("wiki$", ""):gsub("_", "-")
            return label .. " <small>([[:" .. langCode .. ":" .. data.title .. "|" .. langCode .. "]])</small>"
        end
    end

    -- Priority 3: Wikidata fallback
    return label .. " <small>([[:d:" .. itemId .. "|" .. i18n.wd_label .. "]])</small>"
end

--[[────────────────────────────────────────────────────────────────────────────
  SECTION 4: MAIN ENTRY POINT
────────────────────────────────────────────────────────────────────────────]]
--- Main function to display organism list with citations
-- @param frame table MediaWiki frame object containing arguments
-- @return string Formatted organism list with references
function p.main(frame)
    -- Handle both direct invoke and template parameter passing
    local args = frame.args
    if not args.qid or args.qid == "" then
        args = frame:getParent().args
    end

    -- Extract parameters with defaults
    local qid = (args.qid and args.qid ~= "") and args.qid or mw.wikibase.getEntityIdForCurrentPage()
    local numval = tonumber(args.numval) or 5
    local showSources = (args.sources ~= "false" and args.sources ~= "no")

    -- Validate entity and P703 claims exist
    local entity = mw.wikibase.getEntity(qid)
    if not entity or not entity.claims or not entity.claims.P703 then
        return i18n.no_organism
    end

    -- Process claims
    local claims = entity.claims.P703
    local count = #claims
    local results = {}

    for i = 1, math.min(count, numval) do
        local claim = claims[i]
        if claim.mainsnak and claim.mainsnak.datavalue then
            local id = claim.mainsnak.datavalue.value.id
            local link = getDynamicLink(id)
            local ref = showSources and getCleanRef(frame, claim) or ""
            table.insert(results, link .. ref)
        end
    end

    -- Format output with proper pluralization
    local lang = mw.getContentLanguage()
    local label = lang:plural(count, i18n.organism, i18n.organisms)
    local listStr = table.concat(results, i18n.separator)

    if count > numval then
        return count .. " " .. label .. ", " .. i18n.including .. ": " .. listStr
    else
        return count .. " " .. label .. ": " .. listStr
    end
end

--[[────────────────────────────────────────────────────────────────────────────
  SECTION 5: METATABLE FOR DIRECT INVOCATION
  
  Allows calling the module as {{#invoke:P703|...}} or simply {{P703|...}}
────────────────────────────────────────────────────────────────────────────]]
setmetatable(
    p,
    {
        __call = function(t, frame)
            return p.main(frame)
        end
    }
)

return p