package main

import (
	"bytes"
	"strings"
	"testing"
)

const (
	svSE = "../../data/sv_SE"
	enUS = "../../data/en_US"
)

// runOut runs the CLI and returns exit code, stdout, stderr.
func runOut(args ...string) (int, string, string) {
	var out, errb bytes.Buffer
	code := run(args, &out, &errb)
	return code, out.String(), errb.String()
}

func TestRunOutputsValue(t *testing.T) {
	code, out, errb := runOut("-data-path", svSE, "person")
	if code != 0 {
		t.Fatalf("run = %d, stderr=%q", code, errb)
	}
	if strings.TrimSpace(out) == "" {
		t.Fatalf("empty output, stderr=%q", errb)
	}
	if !strings.HasSuffix(out, "\n") {
		t.Errorf("output should end with newline, got %q", out)
	}
}

func TestRunDotPath(t *testing.T) {
	// person.last descends to just a surname — never the full "First Last".
	code, full, _ := runOut("-seed", "7", "-data-path", svSE, "person")
	if code != 0 {
		t.Fatalf("person run = %d", code)
	}
	code, last, errb := runOut("-seed", "7", "-data-path", svSE, "person.last")
	if code != 0 {
		t.Fatalf("person.last run = %d, stderr=%q", code, errb)
	}
	if strings.TrimSpace(last) == "" {
		t.Fatal("empty person.last output")
	}
	if last == full {
		t.Errorf("person.last %q should differ from person %q", last, full)
	}
}

func TestRunSeedDeterministic(t *testing.T) {
	_, a, _ := runOut("-seed", "42", "-data-path", svSE, "address")
	_, b, _ := runOut("-seed", "42", "-data-path", svSE, "address")
	if a != b {
		t.Errorf("same seed diverged: %q != %q", a, b)
	}
}

func TestRunRepeat(t *testing.T) {
	// -repeat N prints N values, one per line by default.
	code, out, errb := runOut("-seed", "1", "-repeat", "3", "-data-path", svSE, "word")
	if code != 0 {
		t.Fatalf("run = %d, stderr=%q", code, errb)
	}
	lines := strings.Split(strings.TrimRight(out, "\n"), "\n")
	if len(lines) != 3 {
		t.Errorf("repeat=3 gave %d lines: %q", len(lines), out)
	}
}

func TestRunSeparator(t *testing.T) {
	// -separator joins the repeated values instead of newlines.
	code, out, errb := runOut("-repeat", "3", "-separator", ",", "-data-path", svSE, "word")
	if code != 0 {
		t.Fatalf("run = %d, stderr=%q", code, errb)
	}
	if n := strings.Count(out, "\n"); n != 1 {
		t.Errorf("want one trailing newline, got %d: %q", n, out)
	}
	if !strings.Contains(out, ",") {
		t.Errorf("values should be comma-joined: %q", out)
	}
}

func TestRunRepeatAdvancesRNG(t *testing.T) {
	// Each repeat is a fresh draw, not the same value N times.
	code, out, errb := runOut("-seed", "1", "-repeat", "5", "-data-path", svSE, "person")
	if code != 0 {
		t.Fatalf("run = %d, stderr=%q", code, errb)
	}
	uniq := map[string]bool{}
	for _, l := range strings.Split(strings.TrimRight(out, "\n"), "\n") {
		uniq[l] = true
	}
	if len(uniq) < 2 {
		t.Errorf("repeat should vary output, all identical: %q", out)
	}
}

func TestRunRepeatInvalid(t *testing.T) {
	// A non-positive repeat is misuse.
	for _, r := range []string{"0", "-1"} {
		code, _, errb := runOut("-repeat", r, "-data-path", svSE, "word")
		if code != 2 {
			t.Errorf("repeat=%s = %d, want 2", r, code)
		}
		if errb == "" {
			t.Errorf("repeat=%s: want an error message", r)
		}
	}
}

func TestRunUsageOnMissingArgs(t *testing.T) {
	// Need at least one -data-path and exactly one positional path; else misuse.
	for _, args := range [][]string{{}, {"-data-path", svSE}, {"person"}} {
		code, _, errb := runOut(args...)
		if code != 2 {
			t.Errorf("run(%v) = %d, want 2", args, code)
		}
		if !strings.Contains(errb, "Usage") {
			t.Errorf("run(%v) stderr = %q, want usage", args, errb)
		}
	}
}

func TestRunMultipleDataPaths(t *testing.T) {
	// -data-path repeats: dirs merge, last wins; the path stays positional.
	code, out, errb := runOut("-data-path", enUS, "-data-path", svSE, "person")
	if code != 0 {
		t.Fatalf("run(multi-dir) = %d, stderr=%q", code, errb)
	}
	if strings.TrimSpace(out) == "" {
		t.Fatal("empty output for multi-dir run")
	}
}

func TestRunUnknownCategoryFails(t *testing.T) {
	code, _, errb := runOut("-data-path", svSE, "nope")
	if code != 1 {
		t.Fatalf("run = %d, want 1", code)
	}
	if !strings.Contains(errb, "nope") {
		t.Errorf("stderr %q should name the unknown category", errb)
	}
}

func TestRunMissingDirFails(t *testing.T) {
	code, _, errb := runOut("-data-path", "../../data/nope", "person")
	if code != 1 {
		t.Fatalf("run = %d, want 1", code)
	}
	if errb == "" {
		t.Error("want an error message on stderr")
	}
}