package fejkdata

import (
	"strings"
	"testing"
)

func tmpl(t *testing.T, f *Generator, input string) string {
	t.Helper()
	s, err := f.FakeTemplate(input)
	if err != nil {
		t.Fatalf("FakeTemplate(%q): %v", input, err)
	}
	return s
}

func shipped(t *testing.T, opts ...Option) *Generator {
	t.Helper()
	f, err := New(append([]Option{WithSeed(1)}, opts...)...)
	if err != nil {
		t.Fatal(err)
	}
	return f
}

func TestFakeTemplateFormatString(t *testing.T) {
	f := shipped(t)
	got := tmpl(t, f, "name: {/sv_SE.person.last}")
	if !strings.HasPrefix(got, "name: ") || strings.HasSuffix(got, " ") || strings.Contains(got, "{") {
		t.Fatalf("FakeTemplate = %q, want a rendered last name after the prefix", got)
	}
}

func TestFakeTemplateJSONObject(t *testing.T) {
	f := shipped(t)
	seen := map[string]bool{}
	for i := 0; i < 50; i++ {
		seen[tmpl(t, f, `{"format":"name: {x}","x":["bosse","lina"]}`)] = true
	}
	if !seen["name: bosse"] || !seen["name: lina"] || len(seen) != 2 {
		t.Fatalf("JSON template produced %v, want both names", seen)
	}
}

func TestFakeTemplateJSONArray(t *testing.T) {
	f := shipped(t)
	seen := map[string]bool{}
	for i := 0; i < 50; i++ {
		seen[tmpl(t, f, `["foo","bar","baz"]`)] = true
	}
	if len(seen) != 3 {
		t.Fatalf("JSON array choice produced %v, want three items", seen)
	}
}

func TestFakeTemplateCorrelatedReferences(t *testing.T) {
	dir := writeData(t, map[string]string{
		"person": `[{"format":"{first} {last}","first":"Ada","last":"Lovelace"},{"format":"{first} {last}","first":"Bo","last":"Ek"}]`,
	})
	f := newGenerator(t, dir, WithSeed(1))
	for i := 0; i < 100; i++ {
		got := tmpl(t, f, "{/person.first} {/person.last}")
		if got != "Ada Lovelace" && got != "Bo Ek" {
			t.Fatalf("correlated references = %q, want one person's first and last", got)
		}
	}
}

func TestFakeTemplateDeterministic(t *testing.T) {
	a, b := shipped(t), shipped(t)
	for i := 0; i < 20; i++ {
		in := "row: {/misc.uuid} {digits(3)}"
		if x, y := tmpl(t, a, in), tmpl(t, b, in); x != y {
			t.Fatalf("same seed diverged: %q != %q", x, y)
		}
	}
}

func TestFakeTemplateErrors(t *testing.T) {
	f := shipped(t)
	for _, c := range []struct {
		input string
		want  string
	}{
		{`{"x":"Q"}`, "missing string \"format\""},
		{`"{x}"`, `no field "x"`},
		{`"{digits(0)}"`, "must be positive"},
		{`name: {/no.such.path}`, "no entry"},
		{`name: {..nope}`, "no folder above"},
		{`{"format":"x"}`, "is a string"},
		{`{/misc.country} {/misc.country.alpha2}`, "renders a level"},
	} {
		_, err := f.FakeTemplate(c.input)
		if err == nil || !strings.Contains(err.Error(), c.want) {
			t.Errorf("FakeTemplate(%q) = %v, want an error containing %q", c.input, err, c.want)
		}
	}
}

func TestNewTemplateReusable(t *testing.T) {
	f := shipped(t)
	tmpl, err := f.NewTemplate(`{digits(2)}`)
	if err != nil {
		t.Fatalf("NewTemplate: %v", err)
	}
	seen := map[string]bool{}
	for i := 0; i < 50; i++ {
		seen[tmpl.Fake()] = true
	}
	if len(seen) < 2 {
		t.Fatalf("Template.Fake() repeated %v, want varied draws from one compile", seen)
	}
}

func TestFakeTemplateRepeatBound(t *testing.T) {
	f := shipped(t)
	_, err := f.FakeTemplate(`{"format":"{x}","repeat":200,"x":{"format":"{y}","repeat":200,"y":{"format":"z","repeat":200}}}`)
	if err == nil || !strings.Contains(err.Error(), "maximum") {
		t.Errorf("nested repeat over the cap = %v, want it rejected naming the maximum", err)
	}
}