use std::sync::Arc;

use axum::extract::{Query, State};
use axum::http::StatusCode;
use axum::response::{IntoResponse, Json};
use axum::Extension;
use serde::Deserialize;
use tracing::{info, warn};

use crate::auth::OptionalUser;
use crate::consts::{DEFAULT_PROPERTIES_LIMIT, POSTCODE_SEARCH_OFFSET};
use crate::licensing::{check_license_point, resolve_share_code};
use crate::parsing::{parse_filters_with_poi, row_passes_filters, row_passes_poi_filters};
use crate::state::SharedState;
use crate::utils::normalize_postcode;

use super::properties::{HexagonPropertiesResponse, Property};
use super::travel_time::{load_travel_data, parse_optional_travel, row_passes_travel_filters};

#[derive(Deserialize)]
pub struct PostcodePropertiesParams {
    pub postcode: String,
    pub filters: Option<String>,
    /// Pipe-separated travel time entries: `mode:slug|mode:slug:min:max`.
    /// Optional min:max applies as a filter (exclude properties outside range).
    pub travel: Option<String>,
    pub limit: Option<usize>,
    pub offset: Option<usize>,
    /// Exact address to rank first when opening properties from address search.
    pub focus_address: Option<String>,
    /// Share-link code; grants bbox-scoped access for unlicensed users.
    pub share: Option<String>,
}

pub async fn get_postcode_properties(
    State(shared): State<Arc<SharedState>>,
    Extension(user): Extension<OptionalUser>,
    Query(params): Query<PostcodePropertiesParams>,
) -> Result<Json<HexagonPropertiesResponse>, axum::response::Response> {
    let state = shared.load_state();
    let normalized = normalize_postcode(&params.postcode);

    let pc_idx = match state.postcode_data.postcode_to_idx.get(&normalized) {
        Some(&idx) => idx,
        None => {
            warn!(postcode = %normalized, "Postcode not found");
            return Err((
                StatusCode::NOT_FOUND,
                format!("Postcode not found: {}", normalized),
            )
                .into_response());
        }
    };
    let (centroid_lat, centroid_lon) = state.postcode_data.centroids[pc_idx];

    let share_bounds = resolve_share_code(&state, params.share.as_deref()).await;
    check_license_point(
        &user.0,
        centroid_lat as f64,
        centroid_lon as f64,
        share_bounds,
    )?;

    let quant = state.data.quant_ref();
    let poi_quant = state.data.poi_metrics.quant_ref();
    let (parsed_filters, parsed_enum_filters, parsed_poi_filters) = parse_filters_with_poi(
        params.filters.as_deref(),
        &state.feature_name_to_index,
        &state.data.enum_values,
        &quant,
        &state.data.poi_metrics.name_to_index,
        &poi_quant,
    )
    .map_err(|err| (StatusCode::BAD_REQUEST, err).into_response())?;
    let num_filters = parsed_filters.len() + parsed_enum_filters.len() + parsed_poi_filters.len();
    let filters_str = params.filters;
    let has_poi_filters = !parsed_poi_filters.is_empty();
    let travel_entries = parse_optional_travel(params.travel.as_deref())
        .map_err(|err| (StatusCode::BAD_REQUEST, err).into_response())?;

    let postcode_str = normalized;
    let focus_address = params
        .focus_address
        .as_deref()
        .map(str::trim)
        .filter(|address| !address.is_empty())
        .map(str::to_ascii_lowercase);

    let result = tokio::task::spawn_blocking(move || {
        let t0 = std::time::Instant::now();
        let num_features = state.data.num_features;
        let feature_data = &state.data.feature_data;
        let feature_names = &state.data.feature_names;
        let feature_name_to_index = &state.feature_name_to_index;
        let enum_values = &state.data.enum_values;
        let travel_data = load_travel_data(&state.travel_time_store, &travel_entries)?;
        let has_travel = !travel_entries.is_empty();

        let offset_deg: f64 = POSTCODE_SEARCH_OFFSET;
        let min_lat = centroid_lat as f64 - offset_deg;
        let max_lat = centroid_lat as f64 + offset_deg;
        let min_lon = centroid_lon as f64 - offset_deg;
        let max_lon = centroid_lon as f64 + offset_deg;

        let mut matching_rows: Vec<usize> = Vec::new();
        state
            .grid
            .for_each_in_bounds(min_lat, min_lon, max_lat, max_lon, |row_idx| {
                let row = row_idx as usize;
                if state.data.postcode(row) == postcode_str
                    && row_passes_filters(
                        row,
                        &parsed_filters,
                        &parsed_enum_filters,
                        feature_data,
                        num_features,
                    )
                    && (!has_poi_filters
                        || row_passes_poi_filters(
                            row,
                            &parsed_poi_filters,
                            &state.data.poi_metrics,
                        ))
                {
                    if has_travel
                        && !row_passes_travel_filters(
                            state.data.postcode(row),
                            &travel_entries,
                            &travel_data,
                        )
                    {
                        return;
                    }
                    matching_rows.push(row);
                }
            });

        matching_rows.sort_unstable_by(|&left, &right| {
            let left_address = state.data.address(left).trim();
            let right_address = state.data.address(right).trim();
            let left_focused = focus_address
                .as_ref()
                .is_some_and(|address| left_address.eq_ignore_ascii_case(address));
            let right_focused = focus_address
                .as_ref()
                .is_some_and(|address| right_address.eq_ignore_ascii_case(address));

            right_focused
                .cmp(&left_focused)
                .then(left_address.is_empty().cmp(&right_address.is_empty()))
        });

        let total = matching_rows.len();
        let limit = params.limit.unwrap_or(DEFAULT_PROPERTIES_LIMIT);
        let page_offset = params.offset.unwrap_or(0);
        let truncated = total > page_offset + limit;

        let properties: Vec<Property> = matching_rows
            .iter()
            .skip(page_offset)
            .take(limit)
            .map(|&row| {
                super::properties::build_property(
                    row,
                    &state,
                    feature_names,
                    feature_name_to_index,
                    enum_values,
                )
            })
            .collect();

        let elapsed = t0.elapsed();
        info!(
            postcode = %postcode_str,
            total,
            returned = properties.len(),
            offset = page_offset,
            filters = num_filters,
            filters_raw = filters_str.as_deref().unwrap_or("-"),
            travel_entries = travel_entries.len(),
            ms = format_args!("{:.1}", elapsed.as_secs_f64() * 1000.0),
            "GET /api/postcode-properties"
        );

        Ok(HexagonPropertiesResponse {
            properties,
            total,
            limit,
            offset: page_offset,
            truncated,
        })
    })
    .await
    .map_err(|error| (StatusCode::INTERNAL_SERVER_ERROR, error.to_string()).into_response())?
    .map_err(|error: String| (StatusCode::INTERNAL_SERVER_ERROR, error).into_response())?;

    Ok(Json(result))
}