local api = vim.api
local helper = require("signup.helper")

local M = {}

local SignatureHelp = {}
SignatureHelp.__index = SignatureHelp

function SignatureHelp.new()
	local instance = setmetatable({
		sig_win = nil,
		sig_buf = nil,
		doc_win = nil,
		doc_buf = nil,
		showing = false,
		ns = nil,
		markid = nil,
		timer = nil,
		current_signatures = nil,
		enabled = false,
		normal_mode_active = false,
		current_signature_idx = nil,
		config = nil,
	}, SignatureHelp)

	instance._default_config = {
		silent = false,
		number = true,
		icons = {
			parameter = "",
			method = "󰡱",
			documentation = "󱪙",
		},
		colors = {
			parameter = "#86e1fc",
			method = "#c099ff",
			documentation = "#4fd6be",
			default_value = "#a80888",
		},
		active_parameter_colors = {
			bg = "#86e1fc",
			fg = "#1a1a1a",
		},
		hi_parameter = "LspSignatureActiveParameter",
		win_opts = {
			border = "rounded",
			winblend = 10,
			zindex = 200,
			focusable = false,
			max_height = 10,
			max_width = 80,
			anchor_bias = "below", -- below|above|auto
			relative = "cursor",
			offset_y = 0,
			offset_x = 0,
		},

		trigger_chars = { "(", "," },
		auto_close = true,
		preview_parameters = true,
		debounce_time = 100,
		toggle_key = "<C-k>",
		render_style = {
			separator = true,
			compact = true,
			align_icons = true,
		},
	}

	return instance
end

-- local function signature_index_comment(index)
-- 	if #vim.bo.commentstring ~= 0 then
-- 		return vim.bo.commentstring:format(index)
-- 	else
-- 		return "(" .. index .. ")"
-- 	end
-- end

-- local function markdown_for_signature_list(signatures, config)
-- 	local lines, labels = {}, {}
-- 	local number = config.number and #signatures > 1
-- 	local max_method_len = 0
--
-- 	-- First pass to calculate alignment
-- 	if config.render_style.align_icons then
-- 		for _, signature in ipairs(signatures) do
-- 			max_method_len = math.max(max_method_len, #signature.label)
-- 		end
-- 	end
--
-- 	for index, signature in ipairs(signatures) do
-- 		if not config.render_style.compact then
-- 			table.insert(lines, "")
-- 		end
-- 		table.insert(labels, #lines + 1)
--
-- 		local suffix = number and (" " .. signature_index_comment(index)) or ""
-- 		local padding = config.render_style.align_icons and string.rep(" ", max_method_len - #signature.label) or " "
--
-- 		-- Method signature with syntax highlighting
-- 		table.insert(lines, string.format("```%s", vim.bo.filetype))
-- 		-- table.insert(lines, string.format("%s Method:", config.icons.method))
-- 		table.insert(lines, string.format("%s %s%s%s", config.icons.method, signature.label, padding, suffix))
-- 		table.insert(lines, "```")
--
-- 		-- -- Parameters section
-- 		-- if signature.parameters and #signature.parameters > 0 then
-- 		-- 	if config.render_style.separator then
-- 		-- 		table.insert(lines, string.rep("─", 40))
-- 		-- 	end
-- 		-- 	table.insert(lines, string.format("%s Parameters:", config.icons.parameter))
-- 		-- 	for _, param in ipairs(signature.parameters) do
-- 		-- 		local param_doc = param.documentation and string.format(" - %s", vim.inspect(param.documentation))
-- 		-- 		table.insert(lines, string.format("  • %s = %s", vim.inspect(param.label), param_doc))
-- 		-- 	end
-- 		-- end
--
-- 		-- Documentation section
-- 		if signature.documentation then
-- 			if config.render_style.separator then
-- 				table.insert(lines, string.rep("─", 40))
-- 			end
-- 			table.insert(lines, string.format("%s Documentation:", config.icons.documentation))
-- 			local doc_lines = vim.split(signature.documentation.value or signature.documentation, "\n")
-- 			for _, line in ipairs(doc_lines) do
-- 				table.insert(lines, "  " .. line)
-- 			end
-- 		end
--
-- 		if index ~= #signatures and config.render_style.separator then
-- 			table.insert(lines, string.rep("═", 40))
-- 		end
-- 	end
-- 	return lines, labels
-- end
--
-- function SignatureHelp:create_float_window(contents)
-- 	local max_width = math.min(self.config.max_width, vim.o.columns)
-- 	local max_height = math.min(self.config.max_height, #contents)
--
-- 	-- Calculate optimal position
-- 	local cursor = api.nvim_win_get_cursor(0)
-- 	local cursor_line = cursor[1]
-- 	local screen_line = vim.fn.screenpos(0, cursor_line, 1).row
--
-- 	local row_offset = self.config.floating_window_above_cur_line and -max_height - 1 or 1
-- 	if screen_line + row_offset < 1 then
-- 		row_offset = 2 -- Show below if not enough space above
-- 	end
--
-- 	local win_config = {
-- 		relative = "cursor",
-- 		row = row_offset - 1,
-- 		col = 0,
-- 		width = max_width,
-- 		height = max_height,
-- 		style = "minimal",
-- 		border = self.config.border,
-- 		zindex = 50, -- Ensure it's above most other floating windows
-- 	}
--
-- 	if self.win and api.nvim_win_is_valid(self.win) then
-- 		api.nvim_win_set_config(self.win, win_config)
-- 		api.nvim_win_set_buf(self.win, self.buf)
-- 	else
-- 		self.buf = api.nvim_create_buf(false, true)
-- 		self.win = api.nvim_open_win(self.buf, false, win_config)
-- 	end
--
-- 	vim.bo[self.buf].modifiable = true
-- 	api.nvim_buf_set_lines(self.buf, 0, -1, false, contents)
-- 	vim.bo[self.buf].modifiable = false
-- 	vim.wo[self.win][self.buf].foldenable = false
-- 	vim.wo[self.win][self.buf].wrap = true
-- 	vim.wo[self.win][self.buf].winblend = self.config.winblend
-- 	self.visible = true
-- end
--
function SignatureHelp:hide_sig_win()
	helper.close_float_window(self.sig_win, self.sig_buf)
	self.current_signatures = nil
	self.showing = false
end

function SignatureHelp:hide_doc_win()
	helper.close_float_window(self.doc_win, self.doc_buf)
end

function SignatureHelp:extract_default_value(param_info)
	-- Check if parameter has documentation that might contain default value
	if not param_info.documentation then
		return nil
	end

	local doc = type(param_info.documentation) == "string" and param_info.documentation
		or param_info.documentation.value

	-- Look for common default value patterns
	local patterns = {
		"default:%s*([^%s]+)",
		"defaults%s+to%s+([^%s]+)",
		"%(default:%s*([^%)]+)%)",
	}

	for _, pattern in ipairs(patterns) do
		local default = doc:match(pattern)
		if default then
			return default
		end
	end

	return nil
end

function SignatureHelp:set_active_parameter_highlights(param_str, lines)
	if not self.sig_buf or not api.nvim_buf_is_valid(self.sig_buf) then
		return
	end

	self.ns = api.nvim_create_namespace("lsp_signature_hi_parameter")
	local hi = self.config.hi_parameter

	local s, e, line_num
	for l, line in ipairs(lines) do
		local ss, ee, _ = string.find(line, param_str, 1, true)
		if ss ~= nil then
			line_num = l - 1
			s = ss
			e = ee
		end
	end

	if s and e and s > 0 then
		self.markid = api.nvim_buf_set_extmark(
			self.sig_buf,
			self.ns,
			line_num,
			s,
			{ id = self.markid, end_line = line_num, end_col = e, hl_group = hi, strict = false }
		)
	end
end

function SignatureHelp:display(result)
	if not result or not result.signatures or #result.signatures == 0 then
		self:hide_sig_win()
		return
	end

	local content = helper.convert_signature_help_to_lines(result, self.config.win_opts.max_width)
	if not self.showing then
		self.sig_buf, self.sig_win = helper.create_float_window(content, "lua", self.config.win_opts) -- TODO: programmatically set file type:
		local param_str = helper.get_parameter_label(result)
		self:set_active_parameter_highlights(param_str, content)
		self.showing = true
	end
	local param_str = helper.get_parameter_label(result)
	self:set_active_parameter_highlights(param_str, content)
end

function SignatureHelp:trigger()
	if not self.enabled then
		return
	end

	local params = vim.lsp.util.make_position_params()
	vim.lsp.buf_request(0, "textDocument/signatureHelp", params, function(err, result, _, _)
		if err then
			if not self.config.silent then
				vim.notify("Error in LSP Signature Help: " .. vim.inspect(err), vim.log.levels.ERROR)
			end
			self:hide_sig_win()
			return
		end

		if result and result.signatures and #result.signatures > 0 then
			self.current_signatures = result.signatures
			self:display(result)
		else
			self:hide_sig_win()
			-- Only notify if not silent and if there was actually no signature help
			if not self.config.silent and result then
				vim.notify("No signature help available", vim.log.levels.INFO)
			end
		end
	end)
end

function SignatureHelp:check_capability()
	local clients = vim.lsp.get_clients()
	for _, client in ipairs(clients) do
		if client.server_capabilities.signatureHelpProvider then
			self.enabled = true
			return
		end
	end
	self.enabled = false
end

function SignatureHelp:toggle_normal_mode()
	self.normal_mode_active = not self.normal_mode_active
	if self.normal_mode_active then
		self:trigger()
	else
		self:hide_sig_win()
	end
end

function SignatureHelp:setup_autocmds()
	local group = api.nvim_create_augroup("LspSignatureHelp", { clear = true })

	local function debounced_trigger()
		-- vim.defer_fn(function()
		-- 	self:trigger()
		-- end, 30)
		if self.timer then
			vim.fn.timer_stop(self.timer)
		end
		self.timer = vim.fn.timer_start(self.debounce_time, function()
			self:trigger()
		end)
	end

	api.nvim_create_autocmd({ "InsertEnter", "CursorMovedI" }, {
		group = group,
		callback = function()
			-- vim.notify("trigger")

			-- local cmp_visible = require("cmp").visible()
			-- if cmp_visible then
			-- self:hide()
			-- elseif vim.fn.pumvisible() == 0 then
			debounced_trigger()
			-- else
			-- self:hide()
			-- end
		end,
	})

	api.nvim_create_autocmd({ "CursorMoved" }, {
		group = group,
		callback = function()
			if self.normal_mode_active then
				debounced_trigger()
			end
		end,
	})

	api.nvim_create_autocmd({ "InsertLeave" }, {
		group = group,
		callback = function()
			self:hide_sig_win()
			self.normal_mode_active = false
		end,
	})

	api.nvim_create_autocmd("LspAttach", {
		group = group,
		callback = function()
			vim.defer_fn(function()
				self:check_capability()
			end, 100)
		end,
	})
end

-- Add navigation between multiple signatures
function SignatureHelp:next_signature()
	if not self.current_signatures then
		return
	end
	self.current_signature_idx = (self.current_signature_idx or 0) + 1
	if self.current_signature_idx > #self.current_signatures then
		self.current_signature_idx = 1
	end
	self:display({
		signatures = self.current_signatures,
		activeParameter = self.current_active_parameter,
		activeSignature = self.current_signature_idx - 1,
	})
end

function SignatureHelp:prev_signature()
	if not self.current_signatures then
		return
	end
	self.current_signature_idx = (self.current_signature_idx or 1) - 1
	if self.current_signature_idx < 1 then
		self.current_signature_idx = #self.current_signatures
	end
	self:display({
		signatures = self.current_signatures,
		activeParameter = self.current_active_parameter,
		activeSignature = self.current_signature_idx - 1,
	})
end

function SignatureHelp:setup_keymaps()
	-- Setup toggle keys using the actual config
	local toggle_key = self.config.toggle_key

	if toggle_key then
		vim.keymap.set("n", toggle_key, function()
			self:toggle_normal_mode()
		end, { noremap = true, silent = true, desc = "Toggle signature help in normal mode" })
	end
end

function M.setup(opts)
	-- Ensure setup is called only once
	if M._initialized then
		return M._instance
	end

	opts = opts or {}
	local signature_help = SignatureHelp.new()

	-- Deep merge user config with defaults
	signature_help.config = vim.tbl_deep_extend("force", signature_help._default_config, opts)

	-- Setup highlights with user config
	local function setup_highlights()
		local colors = signature_help.config.colors
		local highlights = {
			SignatureHelpBorder = { link = "FloatBorder" },
			SignatureHelpMethod = { fg = colors.method },
			SignatureHelpParameter = { fg = colors.parameter },
			SignatureHelpDocumentation = { fg = colors.documentation },
			SignatureHelpDefaultValue = { fg = colors.default_value, italic = true },
			LspSignatureActiveParameter = {
				fg = signature_help.config.active_parameter_colors.fg,
				bg = signature_help.config.active_parameter_colors.bg,
			},
		}

		for group, hl_opts in pairs(highlights) do
			vim.api.nvim_set_hl(0, group, hl_opts)
		end
	end

	-- Setup highlights and ensure they persist across colorscheme changes
	setup_highlights()
	vim.api.nvim_create_autocmd("ColorScheme", {
		group = vim.api.nvim_create_augroup("LspSignatureColors", { clear = true }),
		callback = setup_highlights,
	})

	-- Setup autocmds and keymaps
	signature_help:setup_autocmds()
	signature_help:setup_keymaps()

	-- Store instance for potential reuse
	M._initialized = true
	M._instance = signature_help

	return signature_help
end

-- Add version and metadata for lazy.nvim compatibility
M.version = "1.0.0"
M.dependencies = {
	"nvim-treesitter/nvim-treesitter",
}

-- Add API methods for external use

return M