restaurant-finder-app.R

library(mapgl)
library(shiny)
library(geojsonsf)

ui <- fluidPage(
  tags$head(
    tags$style(HTML(
      "
      body { margin: 0; padding: 0; }
      .container-fluid { padding: 0 !important; margin: 0 !important; }
      #map { height: 100vh !important; width: 100vw !important; }
      .restaurants-panel {
        background: white;
        padding: 20px;
        border-radius: 8px;
        box-shadow: 0 4px 20px rgba(0,0,0,0.3);
        max-height: 80vh;
        overflow-y: auto;
      }
      .restaurants-panel h4 {
        margin-top: 0;
        margin-bottom: 15px;
        font-size: 18px;
        color: #d32f2f;
      }
      .restaurants-panel table {
        width: 100%;
        border-collapse: collapse;
        font-size: 14px;
      }
      .restaurants-panel th {
        background: #d32f2f;
        color: white;
        padding: 12px;
        text-align: left;
        font-size: 14px;
        font-weight: 600;
        position: sticky;
        top: 0;
      }
      .restaurants-panel td {
        padding: 10px 12px;
        border-bottom: 1px solid #e0e0e0;
      }
      .restaurants-panel tr:hover {
        background: #f5f5f5;
      }
      .instruction-message {
        text-align: center;
        padding: 20px;
        color: #666;
        font-size: 14px;
      }
    "
    ))
  ),
  maplibreOutput("map", height = "100vh"),
  absolutePanel(
    top = 20,
    left = 20,
    width = 400,
    class = "restaurants-panel",
    uiOutput("restaurants_panel")
  )
)

server <- function(input, output, session) {
  # Store restaurants and buffer geojson
  restaurants <- reactiveVal(NULL)
  buffer_geojson <- reactiveVal(NULL)
  query_attempts <- reactiveVal(0)
  should_query <- reactiveVal(FALSE)

  output$map <- renderMaplibre({
    maplibre(
      style = openfreemap_style("dark"),
      zoom = 3
    ) |>
      set_projection("globe") |>
      add_pmtiles_source(
        id = "places-source",
        url = "https://overturemaps-tiles-us-west-2-beta.s3.amazonaws.com/2025-06-25/places.pmtiles"
      ) |>
      add_circle_layer(
        id = "places-layer",
        source = "places-source",
        source_layer = "place",
        circle_color = "cyan",
        circle_opacity = 0.5,
        circle_radius = 4,
        popup = concat(
          "<strong>",
          get_column("@name"),
          "</strong><br>",
          get_column("categories")
        )
      ) |>
      add_geolocate_control(
        position = "top-right",
        show_user_heading = TRUE
      )
  })

  # When user geolocates
  observeEvent(input$map_geolocate, {
    coords <- input$map_geolocate$coords
    lng <- coords$longitude
    lat <- coords$latitude

    # Fly to location
    maplibre_proxy("map") |>
      fly_to(center = c(lng, lat), zoom = 14)

    # Add buffer using turf_buffer
    maplibre_proxy("map") |>
      turf_buffer(
        coordinates = c(lng, lat),
        radius = 0.5,
        units = "miles",
        source_id = "user_buffer",
        input_id = "buffer_result"
      ) |>
      add_fill_layer(
        id = "buffer_fill",
        source = "user_buffer",
        fill_color = "red",
        fill_opacity = 0.2
      ) |>
      add_line_layer(
        id = "buffer_outline",
        source = "user_buffer",
        line_color = "red",
        line_width = 2
      ) |>
      add_circle_layer(
        id = "user_location",
        source = list(
          type = "geojson",
          data = list(
            type = "Point",
            coordinates = c(lng, lat)
          )
        ),
        circle_color = "blue",
        circle_radius = 8,
        circle_stroke_color = "white",
        circle_stroke_width = 2
      )
  })

  # When buffer result is ready, style map and query restaurants
  observeEvent(input$map_turf_buffer_result, {
    buffer_geom <- input$map_turf_buffer_result$result$geometry

    if (is.null(buffer_geom)) {
      return()
    }

    buffer_geojson(buffer_geom)

    # Apply styling to the map
    maplibre_proxy("map") |>
      set_paint_property(
        "places-layer",
        "circle-color",
        list(
          "case",
          list(
            "all",
            list("==", list("distance", buffer_geom), 0),
            list("in", "restaurant", list("get", "categories"))
          ),
          "#ff6600",
          "cyan"
        )
      ) |>
      set_paint_property(
        "places-layer",
        "circle-radius",
        list(
          "case",
          list(
            "all",
            list("==", list("distance", buffer_geom), 0),
            list("in", "restaurant", list("get", "categories"))
          ),
          8,
          4
        )
      ) |>
      set_paint_property(
        "places-layer",
        "circle-opacity",
        list(
          "case",
          list(
            "all",
            list("==", list("distance", buffer_geom), 0),
            list("in", "restaurant", list("get", "categories"))
          ),
          1,
          0.2
        )
      )

    # Use a simple delayed query approach
    buffer_geom_copy <- buffer_geom

    # Try at 3 seconds
    later::later(
      function() {
        print("Query attempt 1 (3s)")
        query_rendered_features(
          maplibre_proxy("map", session = session),
          layer_id = "places-layer",
          filter = list(
            "all",
            list("==", list("distance", buffer_geom_copy), 0),
            list("in", "restaurant", list("get", "categories"))
          ),
          callback = function(features) {
            if (!is.null(features) && nrow(features) > 0) {
              print(paste(
                "Success at 3s! Found",
                nrow(features),
                "restaurants"
              ))
              restaurants(features)
            } else {
              print("Attempt 1 - Features found: 0")
            }
          }
        )
      },
      3
    )

    # Try again at 5 seconds if first didn't work
    later::later(
      function() {
        if (!is.null(isolate(restaurants()))) {
          return()
        } # Already found
        print("Query attempt 2 (5s)")
        query_rendered_features(
          maplibre_proxy("map", session = session),
          layer_id = "places-layer",
          filter = list(
            "all",
            list("==", list("distance", buffer_geom_copy), 0),
            list("in", "restaurant", list("get", "categories"))
          ),
          callback = function(features) {
            if (!is.null(features) && nrow(features) > 0) {
              print(paste(
                "Success at 5s! Found",
                nrow(features),
                "restaurants"
              ))
              restaurants(features)
            } else {
              print("Attempt 2 - Features found: 0")
            }
          }
        )
      },
      5
    )

    # Final try at 7 seconds
    later::later(
      function() {
        if (!is.null(isolate(restaurants()))) {
          return()
        } # Already found
        print("Query attempt 3 (7s)")
        query_rendered_features(
          maplibre_proxy("map", session = session),
          layer_id = "places-layer",
          filter = list(
            "all",
            list("==", list("distance", buffer_geom_copy), 0),
            list("in", "restaurant", list("get", "categories"))
          ),
          callback = function(features) {
            if (!is.null(features) && nrow(features) > 0) {
              print(paste(
                "Success at 7s! Found",
                nrow(features),
                "restaurants"
              ))
              restaurants(features)
            } else {
              print("Attempt 3 - Features found: 0. Giving up.")
            }
          }
        )
      },
      7
    )
  })

  output$restaurants_panel <- renderUI({
    places <- restaurants()

    if (is.null(places)) {
      return(
        div(
          class = "instruction-message",
          h4(
            "Find Restaurants Near You",
            style = "color: #d32f2f; font-size: 18px;"
          ),
          p(
            "Click the geolocate button (top right) to find restaurants within 0.5 miles of your location."
          )
        )
      )
    }

    # Debug: show column names
    print(paste("Number of places found:", nrow(places)))
    print(paste("Column names:", paste(names(places), collapse = ", ")))

    if (nrow(places) == 0) {
      return(
        div(
          class = "instruction-message",
          h4("No Restaurants Found", style = "color: #d32f2f;"),
          p(
            "No restaurants found within 0.5 miles. Try moving to a different location."
          )
        )
      )
    }

    # Extract names - R converts @name to X.name
    names_list <- if ("X.name" %in% names(places)) {
      places[["X.name"]]
    } else if ("@name" %in% names(places)) {
      places[["@name"]]
    } else if ("name" %in% names(places)) {
      places[["name"]]
    } else {
      rep("Unknown", nrow(places))
    }

    div(
      h4(paste("Restaurants Found:", nrow(places))),
      tags$div(
        style = "max-height: 60vh; overflow-y: auto;",
        tags$ul(
          lapply(head(names_list, 50), function(name) {
            tags$li(if (is.na(name) || is.null(name)) "Unknown" else name)
          })
        )
      ),
      if (nrow(places) > 50) {
        p(
          paste("Showing first 50 of", nrow(places), "restaurants"),
          style = "font-size: 12px; color: #666; margin-top: 10px;"
        )
      }
    )
  })
}

shinyApp(ui, server)