package nodes_test

import (
	"context"
	"database/sql"
	"testing"
	"time"

	"github.com/wangjia/pangolin/server/internal/config"
	"github.com/wangjia/pangolin/server/internal/nodes"
	"github.com/wangjia/pangolin/server/internal/store"
)

// --------------------------------------------------------------------------
// C1 · EntitlementForUser is the *other* consumer of migration 000025's
// users.max_devices_override — the per-connection backstop in
// internal/httpapi/nodes.go (DEVICE_LIMIT_EXCEEDED). Before this fix it never
// read the override, so an operator-granted override (e.g. 6) would pass the
// login gate (internal/devices.ResolvePlan reads it) but still get the
// account's *next VPN connection* rejected under the un-overridden plan cap.
//
// No container needed — modernc.org/sqlite is pure Go — so these run in
// normal CI alongside run_sqlite_test.sh's data-layer tests, mirroring
// internal/devices/device_limit_override_test.go.
// --------------------------------------------------------------------------

func openEntitlementTestDB(t *testing.T) *sql.DB {
	t.Helper()
	cfg := &config.Config{Driver: "sqlite", DSN: ":memory:"}
	db, err := store.Open(cfg)
	if err != nil {
		t.Fatalf("store.Open: %v", err)
	}
	t.Cleanup(func() { db.Close() })
	if err := store.MigrateUp(db, "sqlite"); err != nil {
		t.Fatalf("MigrateUp: %v", err)
	}
	return db
}

// insertEntitlementTestUser inserts an active user with an optional
// max_devices_override (NULL when override.Valid is false).
func insertEntitlementTestUser(t *testing.T, db *sql.DB, email string, override sql.NullInt64) int64 {
	t.Helper()
	var (
		res sql.Result
		err error
	)
	if override.Valid {
		res, err = db.Exec(
			`INSERT INTO users (uuid, email, pw_hash, dp_uuid, status, max_devices_override)
			 VALUES (?, ?, 'x', ?, 'active', ?)`,
			"uuid-"+email, email, "dp-"+email, override.Int64)
	} else {
		res, err = db.Exec(
			`INSERT INTO users (uuid, email, pw_hash, dp_uuid, status)
			 VALUES (?, ?, 'x', ?, 'active')`,
			"uuid-"+email, email, "dp-"+email)
	}
	if err != nil {
		t.Fatalf("insert user %s: %v", email, err)
	}
	id, err := res.LastInsertId()
	if err != nil {
		t.Fatalf("last insert id: %v", err)
	}
	return id
}

// giveEntitlementTestSubscription inserts an active subscription for userID
// on the given seeded plan code (free/pro/team, from migration 000007).
func giveEntitlementTestSubscription(t *testing.T, db *sql.DB, userID int64, planCode, source string, expiresAt time.Time) {
	t.Helper()
	var planID int64
	if err := db.QueryRow(`SELECT id FROM plans WHERE code=?`, planCode).Scan(&planID); err != nil {
		t.Fatalf("plan lookup %s: %v", planCode, err)
	}
	if _, err := db.Exec(
		`INSERT INTO subscriptions (user_id, plan_id, expires_at, source) VALUES (?, ?, ?, ?)`,
		userID, planID, expiresAt.UTC(), source); err != nil {
		t.Fatalf("give subscription: %v", err)
	}
}

// TestEntitlementForUser_FreeUserNoOverride: a free user with no override set
// gets the plan's hard-coded free default (1) — unchanged baseline behavior.
func TestEntitlementForUser_FreeUserNoOverride(t *testing.T) {
	db := openEntitlementTestDB(t)
	st := nodes.NewSQLNodeStore(db)
	userID := insertEntitlementTestUser(t, db, "free-none@example.com", sql.NullInt64{})

	ent, err := st.EntitlementForUser(context.Background(), userID)
	if err != nil {
		t.Fatalf("EntitlementForUser: %v", err)
	}
	if ent == nil {
		t.Fatal("ent = nil, want entitlement")
	}
	if ent.PlanCode != "free" {
		t.Errorf("PlanCode = %q, want free", ent.PlanCode)
	}
	if ent.MaxDevices != 1 {
		t.Errorf("MaxDevices = %d, want 1 (free plan default, no override)", ent.MaxDevices)
	}
}

// TestEntitlementForUser_FreeUserWithOverride: same free user, override=6 —
// the free-fallback branch (no active subscription row) must be overridden
// too, otherwise the connect backstop rejects the 2nd..6th device even
// though the login gate (devices.ResolvePlan) already allows them.
func TestEntitlementForUser_FreeUserWithOverride(t *testing.T) {
	db := openEntitlementTestDB(t)
	st := nodes.NewSQLNodeStore(db)
	userID := insertEntitlementTestUser(t, db, "free-override@example.com", sql.NullInt64{Int64: 6, Valid: true})

	ent, err := st.EntitlementForUser(context.Background(), userID)
	if err != nil {
		t.Fatalf("EntitlementForUser: %v", err)
	}
	if ent.PlanCode != "free" {
		t.Errorf("PlanCode = %q, want free (override must not change plan identity)", ent.PlanCode)
	}
	if ent.MaxDevices != 6 {
		t.Errorf("MaxDevices = %d, want 6 (override) — connect backstop must agree with login gate", ent.MaxDevices)
	}
}

// TestEntitlementForUser_ProSubscriptionOverrideWins: a pro-subscription user
// (plan default max_devices=3, migration 000019) with override=2 — the
// subscription branch must also be overridden, even though the override is
// *smaller* than the plan's own cap (operators can tighten a specific
// account too, per internal/devices/store.go:305-306's documented semantics).
func TestEntitlementForUser_ProSubscriptionOverrideWins(t *testing.T) {
	db := openEntitlementTestDB(t)
	st := nodes.NewSQLNodeStore(db)
	userID := insertEntitlementTestUser(t, db, "pro-override@example.com", sql.NullInt64{Int64: 2, Valid: true})
	giveEntitlementTestSubscription(t, db, userID, "pro", "trial", time.Now().UTC().Add(24*time.Hour))

	ent, err := st.EntitlementForUser(context.Background(), userID)
	if err != nil {
		t.Fatalf("EntitlementForUser: %v", err)
	}
	if ent.PlanCode != "pro" {
		t.Errorf("PlanCode = %q, want pro", ent.PlanCode)
	}
	if ent.MaxDevices != 2 {
		t.Errorf("MaxDevices = %d, want 2 (override wins over pro plan's own cap of 3)", ent.MaxDevices)
	}
}

// TestEntitlementForUser_NullOrZeroOverrideDoesNotApply: NULL and 0 both mean
// "no override" — the plan-derived cap must stand (free=1 here).
func TestEntitlementForUser_NullOrZeroOverrideDoesNotApply(t *testing.T) {
	db := openEntitlementTestDB(t)
	st := nodes.NewSQLNodeStore(db)

	nullUser := insertEntitlementTestUser(t, db, "null-override@example.com", sql.NullInt64{})
	zeroUser := insertEntitlementTestUser(t, db, "zero-override@example.com", sql.NullInt64{Int64: 0, Valid: true})

	for _, tc := range []struct {
		name   string
		userID int64
	}{
		{"NULL", nullUser},
		{"zero", zeroUser},
	} {
		t.Run(tc.name, func(t *testing.T) {
			ent, err := st.EntitlementForUser(context.Background(), tc.userID)
			if err != nil {
				t.Fatalf("EntitlementForUser: %v", err)
			}
			if ent.MaxDevices != 1 {
				t.Errorf("MaxDevices = %d, want 1 (no override should apply)", ent.MaxDevices)
			}
		})
	}
}