package customer

import "testing"

func TestPickActiveCompanyID(t *testing.T) {
	assigned := []string{"company-a", "company-b"}

	tests := []struct {
		name        string
		assigned    []string
		token       string
		requested   string
		want        string
		wantErr     bool
		wantErrType error
	}{
		{
			name:      "uses requested company when assigned",
			assigned:  assigned,
			token:     "company-a",
			requested: "company-b",
			want:      "company-b",
		},
		{
			name:        "rejects requested company that is not assigned",
			assigned:    assigned,
			token:       "company-a",
			requested:   "company-c",
			wantErr:     true,
			wantErrType: errCompanyNotAssigned,
		},
		{
			name:     "keeps valid token company",
			assigned: assigned,
			token:    "company-b",
			want:     "company-b",
		},
		{
			name:     "falls back to first assignment when token company was removed",
			assigned: []string{"company-b"},
			token:    "company-a",
			want:     "company-b",
		},
		{
			name:     "returns empty when customer has no companies",
			assigned: nil,
			token:    "company-a",
			want:     "",
		},
		{
			name:     "uses first assignment when token is empty",
			assigned: assigned,
			want:     "company-a",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := pickActiveCompanyID(tt.assigned, tt.token, tt.requested)
			if tt.wantErr {
				if err == nil {
					t.Fatalf("expected error, got nil")
				}
				if tt.wantErrType != nil && err != tt.wantErrType {
					t.Fatalf("expected error %v, got %v", tt.wantErrType, err)
				}
				return
			}
			if err != nil {
				t.Fatalf("unexpected error: %v", err)
			}
			if got != tt.want {
				t.Fatalf("pickActiveCompanyID() = %q, want %q", got, tt.want)
			}
		})
	}
}