-- AscensionExporter - Talent URL Encoder
-- Encodes talents into URL format for https://exil.es/en/wow/talent-calc?build=...

AscensionExporter = _G.AscensionExporter or {}
_G.AscensionExporter = AscensionExporter
local AE = AscensionExporter

local BASE36_CHARS = "0123456789abcdefghijklmnopqrstuvwxyz"

local function encodeRank(rank)
    if rank < 10 then
        return tostring(rank)
    end
    -- For ranks >= 10, use base36 (a=10, b=11, etc)
    if rank <= 35 then
        return BASE36_CHARS:sub(rank + 1, rank + 1)
    end
    return "0"
end

local function toBase36(num)
    if num == 0 then return "0" end
    local result = ""
    while num > 0 do
        local remainder = num % 36
        result = BASE36_CHARS:sub(remainder + 1, remainder + 1) .. result
        num = math.floor(num / 36)
    end
    return result
end

-- Encode talents to URL format
-- Format: `${class}.${tree0}.${tree1}.${tree2}`
-- Each tree is encoded as "index_rank" pairs separated by underscores
-- Example: "0_3_b_5" means slot 0 has rank 3, slot 11 (b in base36) has rank 5
function AE.EncodeTalentsToURL(talentsData, className)
    if not talentsData or not className then
        return nil
    end

    -- Normalize class name to lowercase
    className = className:lower()

    -- Build a structure: 3 talent trees with slots
    -- Each WoW class has 3 talent trees
    local trees = {{}, {}, {}}

    -- Group talents by their tabIndex (1-based in Lua, but we want 0-based for array)
    for _, t in ipairs(talentsData.selected or {}) do
        local tabIndex = t.tabIndex or 1
        local talentIndex = (t.talentIndex or 1) - 1  -- Convert to 0-based index
        local rank = t.rank or 0

        if rank > 0 and tabIndex >= 1 and tabIndex <= 3 then
            table.insert(trees[tabIndex], {
                index = talentIndex,
                rank = rank
            })
        end
    end

    -- Sort each tree by index for consistent encoding
    for _, tree in ipairs(trees) do
        table.sort(tree, function(a, b) return a.index < b.index end)
    end

    -- Encode each tree
    local treeParts = {}
    for _, tree in ipairs(trees) do
        local pairs = {}
        for _, talent in ipairs(tree) do
            local idxStr = toBase36(talent.index)
            local rankStr = encodeRank(talent.rank)
            table.insert(pairs, idxStr .. rankStr)
        end
        table.insert(treeParts, table.concat(pairs, "_"))
    end

    -- Build final URL format: class.tree0.tree1.tree2
    return className .. "." .. table.concat(treeParts, ".")
end

-- Generate full talent calc URL
function AE.GenerateTalentCalcURL(talentsData, className)
    local build = AE.EncodeTalentsToURL(talentsData, className)
    if not build then
        return nil
    end
    return "https://exil.es/en/wow/talent-calc?build=" .. build
end

-- Mark module as loaded
AE._loadedTalentEncoder = true