package main

import (
	"bytes"
	"crypto/sha256"
	"os"
	"os/exec"
	"strings"
	"testing"
)

func TestGreeterHelloPrintsLayeredConfig(t *testing.T) {
	got := runHello(t, nil)
	want := "name=hello-app posts_per_page=10 debug=false"
	if got != want {
		t.Fatalf("output = %q, want %q", got, want)
	}
}

func TestGreeterHelloSeesDevelopmentOverlay(t *testing.T) {
	got := runHello(t, map[string]string{"SUMMER_ENV": "development"})
	want := "name=hello-dev posts_per_page=10 debug=true"
	if got != want {
		t.Fatalf("output = %q, want %q", got, want)
	}
}

func TestGreeterHelloSeesEnvVarOverrideOfPluginDefault(t *testing.T) {
	got := runHello(t, map[string]string{
		"SUMMER_GOLEM15__HELLO__POSTS_PER_PAGE": "25",
	})
	want := "name=hello-app posts_per_page=25 debug=false"
	if got != want {
		t.Fatalf("output = %q, want %q", got, want)
	}
}

func runHello(t *testing.T, env map[string]string) string {
	t.Helper()
	for k, v := range env {
		t.Setenv(k, v)
	}
	var buf bytes.Buffer
	if err := run([]string{"greeter:hello"}, &buf); err != nil {
		t.Fatalf("greeter:hello: %v", err)
	}
	return strings.TrimSpace(buf.String())
}

func TestBuiltBinaryGreeterHello(t *testing.T) {
	first := runSummerBuild(t)
	h1 := generatedHash(t)
	second := runSummerBuild(t)
	h2 := generatedHash(t)
	if h1 != h2 {
		t.Fatalf("generated files changed on second build\nfirst:\n%s\nsecond:\n%s", first, second)
	}

	cmd := exec.Command("./bin/hello", "greeter:hello")
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("bin/hello greeter:hello: %v\n%s", err, out)
	}
	if got := strings.TrimSpace(string(out)); got != "name=hello-app posts_per_page=10 debug=false" {
		t.Fatalf("output = %q, want layered production config", got)
	}
}

func runSummerBuild(t *testing.T) string {
	t.Helper()
	cmd := exec.Command("go", "run", "../../cmd/summer", "build")
	cmd.Dir = "."
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("summer build: %v\n%s", err, out)
	}
	return string(out)
}

func generatedHash(t *testing.T) [32]byte {
	t.Helper()
	var buf bytes.Buffer
	for _, name := range []string{"main.go", "plugins.gen.go"} {
		body, err := os.ReadFile(name)
		if err != nil {
			t.Fatal(err)
		}
		buf.Write(body)
	}
	return sha256.Sum256(buf.Bytes())
}