const std = @import("std");
const print = std.debug.print;

const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;

pub const FreqAmp = struct {
	
	freq: f16,
	r_amp: f16,
	
	pub fn create(allocator: Allocator, freq: f16, r_amp: f16) !*FreqAmp {
	
		const fa = try allocator.create(FreqAmp);
		fa.* = .{.freq = freq, .r_amp = r_amp};
		return fa;
		
	}
	
	pub fn prnt(self: *FreqAmp) void {
		print("<{d}::{d}>\n", .{self.freq, self.r_amp});
	}
	
};

pub const FreqAmpList = struct {
	
	allocator: Allocator,
	refcount: u64,
	lst: ArrayList(*FreqAmp),
	

	pub fn create(allocator: Allocator) !*FreqAmpList {
	
		const lst = ArrayList(*FreqAmp).init(allocator);
		const fal = try allocator.create(FreqAmpList);
		
		fal.* = .{
			.allocator = allocator,
			.refcount = 0,
			.lst = lst,	
		};
		
		return fal;
		
	}

	pub fn deinit(self: *FreqAmpList) void {
		
		for (self.lst.items) |freqamp| {
			self.allocator.destroy(freqamp);
		}
	
		self.lst.deinit();
	}

	pub fn prnt(self: *FreqAmpList) void {
		
		print("<Freqamp List (referenced {d} times)>\n", .{self.refcount});
		
		for (self.lst.items) |freqamp| {
			freqamp.prnt();
		}
	
		print("<Freqamp List End>\n", .{});
	}
	
};

pub const FreqAmpBuffer = struct {
	
	const buffer_ticks_default = 44100;
	
	allocator: Allocator,
	buffer_ticks: u32 = buffer_ticks_default,
	current_tick: u32,
	freqamps: [buffer_ticks_default]*FreqAmpList,
		
	pub fn init(allocator: Allocator) !FreqAmpBuffer {
		
		const current_tick = 0;
		
		var initial_list = try FreqAmpList.create(allocator);
		
		initial_list.refcount = buffer_ticks_default;
		initial_list.prnt();
		
		var freqamps: [buffer_ticks_default]*FreqAmpList = undefined;
		
		@memset(&freqamps, initial_list);
		
		return .{
			.allocator = allocator,
			.current_tick = current_tick,
			.freqamps = freqamps,
		};
	}
	
	pub fn deinit(self: *FreqAmpBuffer) void {
		_ = self;
	}

	pub fn increment_tick(self: *FreqAmpBuffer) void {

		const prev_index = self.index_by_tick(self.current_tick);
		
		self.current_tick += 1;
		const cur_index = self.index_by_tick(self.current_tick);
		
		self.freqamps[cur_index].refcount -= 1;
		self.freqamps[prev_index].refcount += 1;
		
		if (self.freqamps[cur_index].refcount == 0) {
			defer self.freqamps[cur_index].deinit();
		}
	
		self.freqamps[cur_index] = self.freqamps[prev_index];
				
	}

	pub fn index_by_tick(self: *FreqAmpBuffer, tick: u32) u32 {
		return tick % self.buffer_ticks;
	}

	pub fn current_index(self: *FreqAmpBuffer) u32 {
		return self.index_by_tick(self.current_tick);
	}

	pub fn current_list(self: *FreqAmpBuffer) *FreqAmpList {
		
		const cur_index = self.index_by_tick(self.current_tick);
		return self.freqamps[cur_index];
		
	}

	pub fn prnt(self: *FreqAmpBuffer) void {
		
		print("CURRENT STATE:\n", .{});
		
		const prev_index = self.index_by_tick(self.current_tick-%1);
		const cur_index = self.index_by_tick(self.current_tick);
		const next_index = self.index_by_tick(self.current_tick+%1);
		
		print("{d}: {*}\n", .{self.current_tick-%1, self.freqamps[prev_index]});
		self.freqamps[prev_index].prnt();
		print("{d}: {*}\n", .{self.current_tick, self.freqamps[cur_index]});
		self.freqamps[cur_index].prnt();
		print("{d}: {*}\n", .{self.current_tick+%1, self.freqamps[next_index]});
		self.freqamps[next_index].prnt();
		
	}

	pub fn reset(self: *FreqAmpBuffer) !void {
		
		const prev_index = self.index_by_tick(self.current_tick -% 1);
		const cur_index = self.index_by_tick(self.current_tick);
		
		if (self.freqamps[cur_index] == self.freqamps[prev_index]) {
			var clist = self.freqamps[cur_index];
					
			clist.refcount -= 1;
			
			if (clist.refcount == 0) {
				defer clist.deinit();
			}
		
			var new_list = try FreqAmpList.create(self.allocator);
			
			new_list.refcount += 1;
			self.freqamps[cur_index] = new_list;
		}
		
	}

	pub fn setfreq(self: *FreqAmpBuffer, freq: f16, r_amp: f16) !void {

		const cur_index = self.index_by_tick(self.current_tick);
		var clist = self.freqamps[cur_index];
				
		// If this freq already is set, sum the r_amps
		
		for (clist.lst.items) |freqamp| {	
				
			if (freqamp.freq == freq) {
				
				freqamp.r_amp = r_amp;
				return;
			}
		
		}
		
		// Otherwise, append new freqamp
		
		const fa = try FreqAmp.create(self.allocator, freq, r_amp);
		
		try clist.lst.append(fa);
		
	}

	pub fn addfreq(self: *FreqAmpBuffer, freq: f16, r_amp: f16) !void {

		const cur_index = self.index_by_tick(self.current_tick);
		var clist = self.freqamps[cur_index];
				
		// If this freq already is set, sum the r_amps
		
		for (clist.lst.items) |freqamp| {	
			
			if (freqamp.freq == freq) {
				
				freqamp.r_amp += r_amp;
								
				if (freqamp.r_amp > 1) {
					freqamp.r_amp = 1;
				}
			
				return;
			}
		
		}
		
		// Otherwise, append new freqamp
		
		const fa = try FreqAmp.create(self.allocator, freq, r_amp);
		
		try clist.lst.append(fa);
		
	}


};

pub fn nmain() !void {
	
	var gpa = std.heap.GeneralPurposeAllocator(.{}){};
	const allocator = gpa.allocator();
	
	var fab = try FreqAmpBuffer.init(allocator);
	defer fab.deinit();
	
	try fab.reset();
	
	try fab.setfreq(440.0, 0.84);
	try fab.setfreq(440, 0.854);
	try fab.setfreq(441.3, 0.8);
	
	try fab.reset();
	fab.prnt();
				
	fab.increment_tick();
	print("\nINCREMENT TICK\n\n", .{});
	
	fab.prnt();
	
}