Imported from archieboo/schengen-counter (AGENTS.md). Install upstream with npx skills add archieboo/schengen-counter. Copyright stays with the author.

Schengen Counter

A single-file R Shiny app (app.R) for tracking compliance with the Schengen 90/180 rule — no more than 90 days in any rolling 180-day window.

Limited to 90 days within any rolling 180-day period. This is computed by looking back 180 days from any date of presence to ensure cumulative stay does not exceed 90 days. The 90/180-day rule requires that on any given day you are in the Schengen Area, you look back at the previous 180 days and count your total days of presence.

What it does

• Loads travel history from CSV upload or public Google Sheet (unauthenticated via googlesheets4)
• Supports multiple travellers; selector at top of main panel
• Anchor date controls the reference point for the 180-day window
• Detects overlapping trips (modal warning); days are deduplicated so never double-counted
• Add/remove trips, export CSV

Layout

Sidebar (width=3): Trip History → Import Data → Add Trip → Remove Trip

Main panel (width=9): Traveller selector + load status → Schengen Usage + Anchor Date → Trip emoji legend → Calendar heatmap

Calendar heatmap

• Always 16 months (4×4), square tiles via coord_equal()
• Weekday labels on every row: axes = "all_x" + scale_x_discrete(position = "top")
• Each trip gets a stable random emoji (seeded from trip names); ⛔ replaces emoji on overstay days
• Gradient fill on presence days: green → yellow → orange → red (red around 70 days used)
• Dotted grey border marks the 180-day window on non-presence days

Main panel background color

Data format

Dependencies for R shiny implimentation

shiny, dplyr, lubridate, ggplot2, purrr, googlesheets4, grid — plus ragg (install separately) for emoji rendering.

Run

Rscript -e "shiny::runApp(port = 3838)" app.R

Key implementation notes

• user_data() expands trips to daily rows then distinct(date) — prevents double-counting overlaps
• rolling_count computed rowwise per date — correct 90/180 implementation
• load_msg reactiveVal drives load status indicator and per-person background color
• Everything in app.R, no modules