extends Node2D

@onready var ground_layer: TileMapLayer = $GroundLayer
@onready var path_layer: TileMapLayer = $PathLayer
@onready var data_layer: TileMapLayer = $DataLayer
@onready var navigation_graph: MPNavigationGraph = $NavigationGraph
#
@onready var player: CharacterBody2D = $Player

var last_dice_result: int = 0
#
var global_transform_size: Vector2 = Vector2(0, 0)
#
const DIRECTIONS: Dictionary   = {
                                     "up": Vector2(0, -1),
                                     "down": Vector2(0, 1),
                                     "left": Vector2(-1, 0),
                                     "right": Vector2(1, 0)
                                 }
var node_positions: Dictionary = {}


func _ready() -> void:
    global_transform_size = Vector2(16, 16) * data_layer.transform.get_scale()

    build_graph()

    # place the player at the first node
    var current_player_position: Vector2 = node_positions.keys()[0]
    player.global_position = local_to_world(current_player_position)

    # bring player to top
    player.z_index = 1

    roll_dice()

    player.finished_movement.connect(roll_dice)


func _physics_process(delta: float) -> void:
    if Input.is_action_just_pressed("draw_toggle_nodes") or Input.is_action_just_pressed("draw_toggle_edges"):
        navigation_graph.draw_nodes = !navigation_graph.draw_nodes
        navigation_graph.draw_edges = !navigation_graph.draw_edges
        navigation_graph.queue_redraw()

var dice_controls_min: int = 2
var dice_controls_max: int = 8


func roll_dice() -> void:
    last_dice_result = randi() % (dice_controls_max - dice_controls_min + 1) + dice_controls_min
    print("Dice result: ", last_dice_result)
    $ResultLabel.text = "Rolled a " + str(last_dice_result)

    # Find possible movement options
    var movement_options: Array[MPNavigationNode] = find_nodes_with_distance(world_to_local(player.global_position), last_dice_result)
    # visualize by spawning an indicator at each possible node, with a click event to move the player
    for node in movement_options:
        # res://scenes/mario-party/TileIndicator.tscn
        var indicator_scene: Node2D = preload("res://scenes/mario-party/TileIndicator.tscn").instantiate()
        indicator_scene.scale = Vector2(2, 2)
        var area_node: Area2D       = indicator_scene.get_node("area")
        area_node.set_data(node.position, "player_movement")
        area_node.indicator_clicked.connect(_on_indicator_clicked)
        indicator_scene.global_position = local_to_world(node.get_position())
        add_child(indicator_scene)


func _on_indicator_clicked(pos: Vector2, type: String) -> void:
    print("Indicator clicked: ", type, " ", pos)
    if type == "player_movement":
        player.move_to(pos)
        # delete all indicators
        for child in get_children():
            if child is Node2D:
                var area_node: Area2D = child.get_node("area")
                if area_node != null:
                    if area_node.get_type() == "player_movement":
                        child.queue_free()


func local_to_world(location: Vector2) -> Vector2:
    return location * global_transform_size + global_transform_size / 2


func world_to_local(location: Vector2) -> Vector2:
    return (location - global_transform_size / 2) / global_transform_size


func build_graph() -> void:
    print("Identifying nodes")
    # Step 1: Place nodes at positions where is_tile is true
    for position in data_layer.get_used_cells():
        var tile_data: TileData = data_layer.get_cell_tile_data(position)
        var is_tile: bool       = tile_data.get_custom_data("is_tile")
        if is_tile:
            var node: MPNavigationNode  = navigation_graph.add_node(position.x, position.y)
            node_positions[position] = node
            var indicator_scene: Node2D = preload("res://scenes/mario-party/TileIndicator.tscn").instantiate()
            var area_node: Area2D       = indicator_scene.get_node("area")
            area_node.set_display_type("node")
            indicator_scene.global_position = local_to_world(position)
            add_child(indicator_scene)

    # Step 2: Connect nodes using flood-fill based on walkable tiles
    print("Connecting nodes")
    for position in node_positions.keys():
        connect_node(position)


func connect_node(start_position: Vector2) -> void:
    var start_node          = node_positions.get(Vector2i(start_position))
    var visited: Dictionary = {}
    visited[start_position] = true
    # print("Connecting node at ", start_position)

    # For each direction, perform flood-fill
    for dir_name in DIRECTIONS.keys():
        var direction     = DIRECTIONS[dir_name]
        var next_position = start_position + direction

        # print("Checking direction ", dir_name, " from ", start_position, " to ", next_position)

        # Ensure the first tile respects the direction
        if not is_valid_direction(next_position, dir_name):
            continue
        # print("Flood-fill in direction ", dir_name, " from ", next_position)

        # Perform flood-fill from the valid tile
        var connected_nodes: Array = flood_fill(next_position, visited)

        # Add connections between the start node and found nodes
        for target_position in connected_nodes:
            if target_position != start_position:
                if node_positions.has(Vector2i(target_position)):
                    var target_node = node_positions.get(Vector2i(target_position))
                    navigation_graph.add_connection(start_node, target_node)
                    print(start_position, " --> ", target_position)


func flood_fill(start_position: Vector2, visited: Dictionary) -> Array:
    var stack: Array[Vector2]           = [start_position]
    var connected_nodes: Array[Vector2] = []

    while stack.size() > 0:
        var current_position = stack.pop_back()
        # print(" - Visiting ", current_position)

        # Skip if already visited
        if visited.has(current_position):
            continue

        visited[current_position] = true

        # Skip if not walkable
        var tile_data: TileData = data_layer.get_cell_tile_data(current_position)
        if tile_data == null:
            continue

        var is_walkable: bool = tile_data.get_custom_data("is_walkable")
        var is_tile: bool     = tile_data.get_custom_data("is_tile")
        if (not is_walkable) and (not is_tile):
            continue

        # If this position is a node, add it to the result
        if is_tile:
            # print(" - Found node tile at ", current_position)
            connected_nodes.append(current_position)

        # Add neighboring tiles to the stack if they respect the direction
        for dir_name in DIRECTIONS.keys():
            var direction         = DIRECTIONS[dir_name]
            var neighbor_position = current_position + direction

            if not visited.has(neighbor_position):
                if is_valid_direction(current_position, dir_name):
                    stack.append(neighbor_position)

    return connected_nodes


func is_valid_direction(position: Vector2, required_dir: String) -> bool:
    var tile_data: TileData = data_layer.get_cell_tile_data(position)
    if tile_data == null:
        return false

    var is_walkable: bool = tile_data.get_custom_data("is_walkable")
    var walk_dir: String  = tile_data.get_custom_data("walk_dir")
    if walk_dir == "":
        walk_dir = "any"

    # print(" L ", position, " ", is_walkable, " ", walk_dir, " ", required_dir)

    # Check if the tile is walkable and allows movement in the required direction
    return is_walkable and (walk_dir == required_dir or walk_dir == "any")


# the first function that evaluates the finished graph
# it is given a starting position and a distance in integers, which represent the amount of nodes to travel to reach the target node(s)
# it will find any nodes that are the given distance away from the starting node and return them in an array
# distance here is the amount of nodes to travel, not the actual distance in pixels
# must use the MPNavigationNode class and the navigation_graph.get_connections(node: MPNavigationNode) function
func find_nodes_with_distance(start_position: Vector2, distance: int) -> Array[MPNavigationNode]:
    var start_node = node_positions.get(Vector2i(start_position))
    if start_node == null:
        print("Error: No node found at starting position ", start_position)
        return []

    # Initialize BFS
    var queue: Array                          = [[start_node, 0]]  # Each element is [node, current_distance]
    var visited: Dictionary                   = {start_node: true}
    var result_nodes: Array[MPNavigationNode] = []

    while queue.size() > 0:
        var current                        = queue.pop_front()
        var current_node: MPNavigationNode = current[0]
        var current_distance: int          = current[1]

        # If the target distance is reached, add the node to the result
        if current_distance == distance:
            result_nodes.append(current_node)
            continue  # Do not explore further from this node

        # If the current distance exceeds the target, stop exploring
        if current_distance > distance:
            break

        # Explore neighbors of the current node
        var neighbors: Array[MPNavigationNode] = navigation_graph.get_connections(current_node)
        for neighbor in neighbors:
            if not visited.has(neighbor):
                visited[neighbor] = true
                queue.append([neighbor, current_distance + 1])

    return result_nodes