import platform
import math
from typing import Any
import pyclipper
from ..model.elements import get_node_links, get_link_nodes, is_pipe
from ..model.pipes import get_pipe
from ..core.database import read, try_read, read_all
from .coordinates import node_has_coord, get_node_coord


def from_postgis_polygon(polygon: str) -> list[tuple[float, float]]:
    boundary = polygon.lower().removeprefix('polygon((').removesuffix('))').split(',')
    xys = []
    for pt in boundary:
        xy = pt.split(' ')
        xys.append((float(xy[0]), float(xy[1])))
    return xys


def to_postgis_polygon(boundary: list[tuple[float, float]]) -> str:
    polygon = ''
    for pt in boundary:
        polygon += f'{pt[0]} {pt[1]},'
    return str(f'polygon(({polygon[:-1]}))')


def to_postgis_linestring(boundary: list[tuple[float, float]]) -> str:
    line = ''
    for pt in boundary:
        line += f'{pt[0]} {pt[1]},'
    return str(f'linestring({line[:-1]})')


def get_nodes_in_boundary(name: str, boundary: list[tuple[float, float]]) -> list[str]:
    rows = read_all(
        name,
        "select node_id from gis.node_geometries "
        "where st_intersects(geom, st_geomfromtext(%s, 900914)) order by node_id",
        (to_postgis_polygon(boundary),),
    )
    return [str(row["node_id"]) for row in rows]


def _get_links_on_boundary(name: str, nodes: list[str]) -> list[str]:
    links: list[str] = []

    for node in nodes:
        node_links = get_node_links(name, node)
        for link in node_links:
            if link in links:
                continue

            link_nodes = get_link_nodes(name, link)
            if link_nodes[0] in nodes and link_nodes[1] not in nodes:
                links.append(link)
            elif link_nodes[0] not in nodes and link_nodes[1] in nodes:
                links.append(link)

    return links


def get_nodes_in_region(name: str, region_id: str) -> list[str]:
    stored = read_all(
        name,
        "select node_id from gis.region_nodes where region_id = %s order by node_id",
        (region_id,),
    )
    if stored:
        return [str(row["node_id"]) for row in stored]
    rows = read_all(
        name,
        "select n.node_id from gis.node_geometries n join gis.regions r "
        "on st_intersects(n.geom, r.boundary) where r.id = %s order by n.node_id",
        (region_id,),
    )
    return [str(row["node_id"]) for row in rows]


def get_links_on_region_boundary(name: str, region_id: str) -> list[str]:
    nodes = get_nodes_in_region(name, region_id)
    return _get_links_on_boundary(name, nodes)


def calculate_convex_hull(name: str, nodes: list[str]) -> list[tuple[float, float]]:
    row = read(
        name,
        "select st_astext(st_convexhull(st_collect(geom))) as boundary "
        "from gis.node_geometries where node_id = any(%s)",
        (nodes,),
    )
    return from_postgis_polygon(str(row["boundary"]))


def _verify_platform():
    _platform = platform.system()
    if _platform != "Windows":
        raise Exception(f'Platform {_platform} unsupported (not yet)')


def _normal(v: tuple[float, float]) -> tuple[float, float]:
    l = math.sqrt(v[0] * v[0] + v[1] * v[1])
    return (v[0] / l, v[1] / l)


def _angle(v: tuple[float, float]) -> float:
    if v[0] >= 0 and v[1] >= 0:
        return math.asin(v[1])
    elif v[0] <= 0 and v[1] >= 0:
        return math.pi - math.asin(v[1])
    elif v[0] <= 0 and v[1] <= 0:
        return math.asin(-v[1]) + math.pi
    elif v[0] >= 0 and v[1] <= 0:
        return math.pi * 2 - math.asin(-v[1])
    return 0


def _angle_of_node_link(node: str, link: str, nodes, links) -> float:
    n1 = node
    n2 = links[link]['node1'] if n1 == links[link]['node2'] else links[link]['node2']
    x1, y1 = nodes[n1]['x'], nodes[n1]['y']
    x2, y2 = nodes[n2]['x'], nodes[n2]['y']
    if y1 == y2:
        v = ((x2 - x1) / abs(x2 - x1), 0.0)
    else:
        v = _normal((x2 - x1, y2 - y1))
    return _angle(v)


class Topology:
    def __init__(self, db: str, nodes: list[str]) -> None:
        self._nodes: dict[str, Any] = {}
        self._max_x_node = ''
        self._node_list: list[str] = []
        for node in nodes:
            if not node_has_coord(db, node):
                continue
            if get_node_links(db, node) == 0:
                continue
            self._nodes[node] = get_node_coord(db, node) | { 'links': [] }
            self._node_list.append(node)
            if self._max_x_node == '' or self._nodes[node]['x'] > self._nodes[self._max_x_node]['x']:
                self._max_x_node = node

        self._links: dict[str, Any] = {}
        self._link_list: list[str] = []
        for node in self._nodes:
            for link in get_node_links(db, node):
                candidate = True
                link_nodes = get_link_nodes(db, link)
                for link_node in link_nodes:
                    if link_node not in self._nodes:
                        candidate = False
                        break
                if candidate:
                    length = get_pipe(db, link)['length'] if is_pipe(db, link) else 0.0
                    self._links[link] = { 'node1' : link_nodes[0], 'node2' : link_nodes[1], 'length' : length }
                    self._link_list.append(link)
                    if link not in self._nodes[link_nodes[0]]['links']:
                        self._nodes[link_nodes[0]]['links'].append(link)
                    if link not in self._nodes[link_nodes[1]]['links']:
                        self._nodes[link_nodes[1]]['links'].append(link)

    def nodes(self):
        return self._nodes
    
    def node_list(self):
        return self._node_list
    
    def max_x_node(self):
        return self._max_x_node

    def links(self):
        return self._links
    
    def link_list(self):
        return self._link_list


def _calculate_boundary(cursor: str, t_nodes: dict[str, Any], t_links: dict[str, Any]) -> tuple[list[str], dict[str, list[str]], list[tuple[float, float]]]:
    in_angle = 0

    vertices: list[str] = []
    path: dict[str, list[str]] = {}
    while True:
        # prevent duplicated node
        if len(vertices) > 0 and cursor == vertices[-1]:
            break
        
        # prevent duplicated path
        if len(vertices) >= 3 and vertices[0] == vertices[-1] and vertices[1] == cursor:
            break

        vertices.append(cursor)

        sorted_links = []
        overlapped_link = ''
        for link in t_nodes[cursor]['links']:
            angle = _angle_of_node_link(cursor, link, t_nodes, t_links)
            if angle == in_angle:
                overlapped_link = link
                continue
            sorted_links.append((angle, link))

        # work into a branch, return
        if len(sorted_links) == 0:
            path[overlapped_link] = []
            cursor = vertices[-2]
            in_angle = _angle_of_node_link(cursor, overlapped_link, t_nodes, t_links)
            continue

        sorted_links = sorted(sorted_links, key=lambda s:s[0])
        out_link = sorted_links[0][1]
        for angle, link in sorted_links:
            if angle > in_angle:
                out_link = link
                break

        path[out_link] = []
        cursor = t_links[out_link]['node1'] if cursor == t_links[out_link]['node2'] else t_links[out_link]['node2']
        in_angle = _angle_of_node_link(cursor, out_link, t_nodes, t_links)

    boundary: list[tuple[float, float]] = []
    for node in vertices:
        boundary.append((t_nodes[node]['x'], t_nodes[node]['y']))

    return (vertices, path, boundary)


def _collect_new_links(in_links: dict[str, list[str]], t_nodes: dict[str, Any], t_links: dict[str, Any], new_nodes: dict[str, Any], new_links: dict[str, Any]) -> tuple[dict[str, Any], dict[str, Any]]:
    for link, pts in in_links.items():
        node1 = t_links[link]['node1']
        node2 = t_links[link]['node2']
        x1, x2 = t_nodes[node1]['x'], t_nodes[node2]['x']
        y1, y2 = t_nodes[node1]['y'], t_nodes[node2]['y']

        if node1 not in new_nodes:
            new_nodes[node1] = { 'x': x1, 'y': y1, 'links': [] }
        if node2 not in new_nodes:
            new_nodes[node2] = { 'x': x2, 'y': y2, 'links': [] }

        x_delta = x2 - x1
        y_delta = y2 - y1
        use_x = abs(x_delta) > abs(y_delta)

        if len(pts) == 0:
            new_links[link] = t_links[link]
        else:
            sorted_nodes: list[tuple[float, str]] = []
            sorted_nodes.append((0.0, node1))
            sorted_nodes.append((1.0, node2))
            i = 0
            for pt in pts:
                x, y = new_nodes[pt]['x'], new_nodes[pt]['y']
                percent = ((x - x1) / x_delta) if use_x else ((y - y1) / y_delta)
                sorted_nodes.append((percent, pt))
                i += 1
            sorted_nodes = sorted(sorted_nodes, key=lambda s:s[0])

            for i in range(1, len(sorted_nodes)):
                l = sorted_nodes[i - 1][1]
                r = sorted_nodes[i][1]
                new_link = f'LINK_[{l}]_[{r}]'
                new_links[new_link] = { 'node1': l, 'node2': r }

    return (new_nodes, new_links)


def calculate_boundary(name: str, nodes: list[str], accurate = False) -> list[tuple[float, float]]:
    topology = Topology(name, nodes)
    t_nodes = topology.nodes()
    t_links = topology.links()
    _, _, boundary = _calculate_boundary(topology.max_x_node(), t_nodes, t_links)
    return boundary


'''
# CClipper2.dll
# int inflate_paths(double* path, size_t size, double delta, int jt, int et, double miter_limit, int precision, double arc_tolerance, double** out_path, size_t* out_size);
# int simplify_paths(double* path, size_t size, double epsilon, int is_closed_path, double** out_path, size_t* out_size);
# void free_paths(double** paths);
'''
def inflate_boundary(name: str, boundary: list[tuple[float, float]], delta: float = 0.5) -> list[tuple[float, float]]:
    if boundary[0] == boundary[-1]:
        del(boundary[-1])

    precision = 2
    scale = 10 ** precision
    path = [(round(x * scale), round(y * scale)) for x, y in boundary]

    offset = pyclipper.PyclipperOffset(miter_limit=2.0)
    offset.AddPath(path, pyclipper.JT_SQUARE, pyclipper.ET_CLOSEDPOLYGON)
    solutions = offset.Execute(round(delta * scale))
    if len(solutions) == 0:
        return []

    result: list[tuple[float, float]] = []
    for x, y in solutions[0]:
        result.append((x / scale, y / scale))
    result.append(result[0])
    return result


def inflate_region(name: str, region_id: str, delta: float = 0.5) -> list[tuple[float, float]]:
    r = try_read(name, "select id, st_astext(boundary) as boundary_geom from gis.regions where id = %s", (region_id,))
    if r == None:
        return []
    boundary = from_postgis_polygon(str(r['boundary_geom']))
    return inflate_boundary(name, boundary, delta)


if __name__ == '__main__':
    _verify_platform()