package models

import (
	"strings"
	"time"
)

/*
Is a branch taking orders right now?

Two things have to be true: the branch exists as far as the platform is
concerned, and the shop has not closed itself for the day. They are different
questions with different owners — Nearle decommissions a branch, a shopkeeper
closes for an afternoon — and this is the only place they are answered
together.

── Reopening is worked out, not scheduled ──────────────────────────────────

A shop that said "back on Monday" is open on Monday because this function says
so, not because a job ran. Nothing has to fire, nothing can be missed, and a
server that was down over the weekend still gets it right. The alternative — a
nightly task flipping the flag — fails silently exactly once and leaves a shop
shut with nobody watching.

── Why the date means the day it REOPENS ───────────────────────────────────

"Closed until the 12th" reads, in English, as open on the 12th. So the date
names the first day back, and a shop closing for today alone sets tomorrow.
The console says "Reopens on" rather than "Closed until" so nobody has to
work that out.
*/
func StoreIsOpen(status string, isOpen bool, closedUntil string, now time.Time) bool {
	// Decommissioned beats everything. A branch Nearle has switched off does
	// not come back because a date passed.
	if !strings.EqualFold(strings.TrimSpace(status), "active") {
		return false
	}

	if isOpen {
		return true
	}

	// Closed, with a date to come back on.
	reopen, ok := parseStoreDate(closedUntil)
	if !ok {
		// Closed with no end in sight — a power cut nobody can put a date on.
		// Stays closed until a person says otherwise, which is the safe way
		// round: a shop wrongly shown open takes orders it cannot fill.
		return false
	}

	today := now.Truncate(24 * time.Hour)
	return !today.Before(reopen.Truncate(24 * time.Hour))
}

/*
Why a shopper cannot order, in words fit to show them.

Empty when the branch is open. Returned straight to the app, so it says what a
person needs to know and not what the database holds.
*/
func StoreClosedReason(status string, isOpen bool, closedUntil string, now time.Time) string {
	if StoreIsOpen(status, isOpen, closedUntil, now) {
		return ""
	}
	if !strings.EqualFold(strings.TrimSpace(status), "active") {
		return "This store is not currently available"
	}
	if reopen, ok := parseStoreDate(closedUntil); ok {
		return "This store is closed today and reopens on " + reopen.Format("2 Jan")
	}
	return "This store is closed today"
}

// Accepts a bare date or a timestamp, because the column is a DATE but GORM
// and the console have both been known to hand over a full RFC3339 string.
// Anything unreadable is "no date", never today.
func parseStoreDate(value string) (time.Time, bool) {
	trimmed := strings.TrimSpace(value)
	if trimmed == "" {
		return time.Time{}, false
	}
	if len(trimmed) >= 10 {
		if parsed, err := time.Parse("2006-01-02", trimmed[:10]); err == nil {
			return parsed, true
		}
	}
	return time.Time{}, false
}