"""Click CLI commands for osm-pt-geojson."""
import json
import sys

import click

from osm_geojson.pt.core import (
    GeoJson,
    OsmError,
    build_route_coords,
    fetch_relation_full,
    make_geojson,
    nearest_coord_index,
    node_name,
    parse_elements,
)


def output_geojson(geojson: GeoJson, output_path: str | None) -> None:
    """Write GeoJSON to a file, or to stdout if output_path is None."""
    text = json.dumps(geojson, ensure_ascii=False, indent=2)
    if output_path:
        with open(output_path, "w", encoding="utf-8") as f:
            f.write(text)
        click.echo(f"Wrote {output_path}", err=True)
    else:
        click.echo(text)


@click.group()
def cli() -> None:
    """OSM public transport route → GeoJSON tool."""


@cli.command("list-stations")
@click.argument("relation_id", type=int)
def list_stations(relation_id: int) -> None:
    """List all stations in an OSM public transport route relation."""
    try:
        data = fetch_relation_full(relation_id)
        nodes, ways, stop_ids, way_ids, tags = parse_elements(data, relation_id)
    except OsmError as e:
        click.echo(f"Error: {e}", err=True)
        sys.exit(1)
    click.echo(f"Route: {tags.get('name', relation_id)}")
    click.echo(f"Stops ({len(stop_ids)}):")
    for i, sid in enumerate(stop_ids, 1):
        if sid in nodes:
            click.echo(f"  {i:2}. {node_name(nodes[sid])}")
        else:
            click.echo(f"  {i:2}. (node {sid} not in response)")


@cli.command("route-between")
@click.argument("relation_id", type=int)
@click.argument("from_station")
@click.argument("to_station")
@click.option("--output", "-o", type=click.Path(), default=None, help="Output file (default: stdout)")
@click.option("--no-stops", is_flag=True, default=False, help="Omit stop points from output.")
def route_between(
    relation_id: int,
    from_station: str,
    to_station: str,
    output: str | None,
    no_stops: bool,
) -> None:
    """Output GeoJSON for the route segment between two named stations."""
    try:
        data = fetch_relation_full(relation_id)
        nodes, ways, stop_ids, way_ids, tags = parse_elements(data, relation_id)
    except OsmError as e:
        click.echo(f"Error: {e}", err=True)
        sys.exit(1)

    route_coords = build_route_coords(way_ids, ways, nodes)

    def find_stop(name: str) -> int | None:
        """Return the node ID of the stop matching name (case-insensitive), or None."""
        for sid in stop_ids:
            if sid in nodes and node_name(nodes[sid]).lower() == name.lower():
                return sid
        return None

    sid_from = find_stop(from_station)
    sid_to = find_stop(to_station)

    errors = []
    if sid_from is None:
        errors.append(f"Station not found: {from_station!r}")
    if sid_to is None:
        errors.append(f"Station not found: {to_station!r}")
    if errors:
        for msg in errors:
            click.echo(f"Error: {msg}", err=True)
        click.echo("Available stations:", err=True)
        for sid in stop_ids:
            if sid in nodes:
                click.echo(f"  {node_name(nodes[sid])}", err=True)
        sys.exit(1)

    assert sid_from is not None and sid_to is not None
    idx_from = nearest_coord_index(nodes[sid_from]["lon"], nodes[sid_from]["lat"], route_coords)
    idx_to = nearest_coord_index(nodes[sid_to]["lon"], nodes[sid_to]["lat"], route_coords)

    geojson = make_geojson(
        route_coords, stop_ids, nodes, tags, idx_from=idx_from, idx_to=idx_to, no_stops=no_stops
    )
    output_geojson(geojson, output)


@cli.command("full-route")
@click.argument("relation_id", type=int)
@click.option("--output", "-o", type=click.Path(), default=None, help="Output file (default: stdout)")
@click.option("--no-stops", is_flag=True, default=False, help="Omit stop points from output.")
def full_route(relation_id: int, output: str | None, no_stops: bool) -> None:
    """Output GeoJSON for the entire route, end to end."""
    try:
        data = fetch_relation_full(relation_id)
        nodes, ways, stop_ids, way_ids, tags = parse_elements(data, relation_id)
    except OsmError as e:
        click.echo(f"Error: {e}", err=True)
        sys.exit(1)
    route_coords = build_route_coords(way_ids, ways, nodes)
    geojson = make_geojson(route_coords, stop_ids, nodes, tags, no_stops=no_stops)
    output_geojson(geojson, output)