local RefreshTask = require("lsp.codelens.refresh_task")
local Row = require("lsp.codelens.row")
local util = require("util")

local REFRESH_DEBOUNCE_MS = 200

---@class ow.lsp.codelens.Session
---@field buf integer
---@field enabled boolean
---@field attached boolean
---@field rows table<integer, ow.lsp.codelens.Row>
---@field current? ow.lsp.codelens.RefreshTask
local Session = {}
Session.__index = Session

---@param session ow.lsp.codelens.Session
local function do_refresh(session)
    if not session.enabled then
        return
    end
    session:abort()
    local task = RefreshTask.new(session)
    session.current = task
    task:run()
end

local refresher = util.keyed_debounce(do_refresh, REFRESH_DEBOUNCE_MS)

---@param buf integer
---@return ow.lsp.codelens.Session
function Session.new(buf)
    return setmetatable({
        buf = buf,
        enabled = false,
        attached = false,
        rows = {},
    }, Session)
end

function Session:abort()
    refresher:cancel(self)
    if self.current then
        self.current:abort()
        self.current = nil
    end
end

function Session:refresh()
    refresher(self)
end

function Session:render()
    if not vim.api.nvim_buf_is_valid(self.buf) then
        return
    end
    if not self.enabled then
        Row.clear_all(self.buf)
        return
    end

    for _, row in pairs(self.rows) do
        row:render(self.buf)
    end

    Row.prune(self.buf, self.rows)
end

function Session:attach()
    if self.attached then
        return
    end
    self.attached = true
    vim.api.nvim_buf_attach(self.buf, false, {
        on_lines = function()
            if not self.enabled then
                self.attached = false
                return true
            end
            self:refresh()
        end,
        on_reload = function()
            if self.enabled then
                self:refresh()
            end
        end,
        on_detach = function()
            self.attached = false
        end,
    })
end

---@param value boolean
function Session:enable(value)
    self.enabled = value
    if value then
        self:attach()
        self:refresh()
    else
        self:abort()
        self.rows = {}
        self:render()
    end
end

function Session:toggle()
    self:enable(not self.enabled)
end

return Session