local config = require("inbox.config")
local indexers = require("inbox.indexers")
local renderers = require("inbox.renderers")
local utils = require("inbox.utils")
local view = require("inbox.view")

local M = {
	buffers = {},
}

function M.select()
	local mode = vim.api.nvim_get_mode().mode
	local is_visual = mode:match("^[vV]")

	local entries = {}
	if is_visual then
		-- This is the best way to get the visual selection at the moment
		-- https://github.com/neovim/neovim/pull/13896
		local _, start_lnum, _, _ = unpack(vim.fn.getpos("v"))
		local _, end_lnum, _, _, _ = unpack(vim.fn.getcurpos())
		if start_lnum > end_lnum then
			start_lnum, end_lnum = end_lnum, start_lnum
		end
		for i = start_lnum, end_lnum do
			local entry = M.get_entry_on_line(0, i)
			if entry then
				table.insert(entries, entry)
			end
		end
	else
		local entry = M.get_id_on_cursor()
		if entry then
			table.insert(entries, entry)
		end
	end
end

function M.open(maildir)
	if maildir == nil then
		maildir = config.default_maildir
	end

	if M.buffers[maildir] == nil or vim.api.nvim_buf_is_valid(M.buffers[maildir]) then
		M.buffers[maildir] = view.initialize_inbox(maildir)
	end

	vim.api.nvim_set_current_buf(M.buffers[maildir])
end

function M.open_entry(id, content_type)
	if id == nil then
		id = M.get_cursor_id()
		if id == nil then
			return nil
		end
	end

	if M.buffers[id] == nil or vim.api.nvim_buf_is_valid(M.buffers[id]) then
		local maildir = utils.parse_scheme(0)
		if maildir == nil then
			return
		end

		local bufnr = view.initialize_entry(maildir, id, content_type)
		M.buffers[id] = bufnr
	end

	vim.api.nvim_set_current_buf(M.buffers[id])
end

function M.select_part()
	local entry = M.get_cursor_entry()

	if entry == nil then
		return nil
	end

	vim.ui.select(entry.parts, {
		prompt = "Part",
		format_item = function(item)
			return item["content-type"]
		end,
	}, function(part)
		M.open_entry(entry.id, part)
	end)
end

function M.toggle_headers(bufnr)
	if bufnr == nil or bufnr == 0 then
		bufnr = vim.api.nvim_get_current_buf()
	end

	if vim.b[bufnr].show_all_headers then
		vim.b[bufnr].show_all_headers = false
	else
		vim.b[bufnr].show_all_headers = true
	end

	view.render_headers(bufnr)
end

---@return inbox.Entry? entry
function M.get_cursor_entry()
	local id = M.get_cursor_id()
	if id == nil then
		vim.notify(("Failed to get entry with id: %s"):format(id), vim.log.levels.ERROR)
		return nil
	end

	return M.indexer.get_entry(id)
end

---@return string? id
function M.get_cursor_id()
	local lnum = vim.api.nvim_win_get_cursor(0)[1]
	local id = vim.b[0].inbox_ids[lnum]

	if id == nil then
		vim.notify("Failed to get entry under cursor", vim.log.levels.ERROR)
		return nil
	end

	return id
end

---@param opts inbox.Config
function M.setup(opts)
	config.setup(opts)
	indexers.setup(config)
	renderers.setup(config)

	for sign, value in pairs(config.flags) do
		local name = utils.sign_name(sign)
		vim.fn.sign_define(name, value)
	end

	M.augroup = vim.api.nvim_create_augroup("Inbox", { clear = true })
end

return M