local SNIPPET_FORMAT = vim.lsp.protocol.InsertTextFormat.Snippet
local SNIPPET_KIND = vim.lsp.protocol.CompletionItemKind.Snippet

---@param raw lsp.CompletionItem
---@return string
local function label_stem(raw)
    return raw.label:match("[^(]+") or raw.label
end

---@param raw lsp.CompletionItem
---@return string
local function edit_text(raw)
    if raw.textEdit then
        return raw.textEdit.newText
    end

    return raw.insertText or raw.label
end

---@param raw lsp.CompletionItem
---@return string
local function get_word(raw)
    if raw.insertTextFormat == SNIPPET_FORMAT then
        return raw.filterText or label_stem(raw)
    end
    return edit_text(raw)
end

---@param raw lsp.CompletionItem
---@return string
local function get_abbr(raw)
    local abbr = label_stem(raw)
    if raw.kind == SNIPPET_KIND then
        abbr = abbr .. "~"
    end
    return abbr
end

---@param raw lsp.CompletionItem
---@return string?
local function get_detail(raw)
    return raw.detail or vim.tbl_get(raw, "labelDetails", "description")
end

---@param raw lsp.CompletionItem
---@return string?
local function get_doc(raw)
    local doc = raw.documentation
    if not doc then
        return nil
    end
    return doc.value or doc
end

---@param raw lsp.CompletionItem
---@return string?
local function get_snippet(raw)
    if raw.insertTextFormat == SNIPPET_FORMAT then
        return edit_text(raw)
    end
    return nil
end

---@class ow.lsp.completion.Item
---@field word string
---@field abbr string
---@field detail string?
---@field doc string?
---@field snippet string?
---@field client_id integer
---@field raw lsp.CompletionItem
local Item = {}
Item.__index = Item

---@param raw lsp.CompletionItem
---@param client_id integer
---@return ow.lsp.completion.Item
function Item.from_lsp(raw, client_id)
    return setmetatable({
        word = get_word(raw),
        abbr = get_abbr(raw),
        detail = get_detail(raw),
        doc = get_doc(raw),
        snippet = get_snippet(raw),
        client_id = client_id,
        raw = raw,
    }, Item)
end

---@param resolved lsp.CompletionItem
function Item:apply_resolved(resolved)
    self.raw = vim.tbl_deep_extend("force", self.raw, resolved)
    self.detail = get_detail(self.raw)
    self.doc = get_doc(self.raw)
    if self.snippet then
        self.snippet = edit_text(self.raw)
    end
end

---@param completed vim.v.completed_item
---@return ow.lsp.completion.Item?
function Item.from_user_data(completed)
    local t = vim.tbl_get(completed, "user_data", "ow", "item")
    if t then
        return setmetatable(t, Item)
    end
    return nil
end

return Item