package templates

import (
	"errors"
	"os"
	"path/filepath"
	"testing"

	"galaxy/mail/internal/domain/common"

	"github.com/stretchr/testify/require"
)

func TestNewCatalogBuildsImmutableRegistry(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "subject.tmpl"), "Your login code")
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "text.tmpl"), "Code: {{.code}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "fr-fr", "subject.tmpl"), "Tour {{.turn_number}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "fr-fr", "text.tmpl"), "Bonjour {{with .player}}{{.name}}{{end}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "fr-fr", "html.tmpl"), "<p>{{.player.name}}</p>")

	catalog, err := NewCatalog(rootDir)
	require.NoError(t, err)
	require.Equal(t, filepath.Clean(rootDir), catalog.RootDir())

	locale, err := common.ParseLocale("fr-FR")
	require.NoError(t, err)
	resolved, err := catalog.Lookup(common.TemplateID("game.turn_ready"), locale)
	require.NoError(t, err)
	require.False(t, resolved.LocaleFallbackUsed())
	require.Equal(t, common.Locale("fr-FR"), resolved.ResolvedLocale())
	require.Equal(t, []string{"player", "player.name", "turn_number"}, resolved.RequiredVariablePaths())

	subject, err := resolved.ExecuteSubject(map[string]any{
		"turn_number": 54,
		"player": map[string]any{
			"name": "Pilot",
		},
	})
	require.NoError(t, err)
	require.Equal(t, "Tour 54", subject)

	textBody, err := resolved.ExecuteText(map[string]any{
		"player": map[string]any{
			"name": "Pilot",
		},
	})
	require.NoError(t, err)
	require.Equal(t, "Bonjour Pilot", textBody)

	htmlBody, ok, err := resolved.ExecuteHTML(map[string]any{
		"player": map[string]any{
			"name": "Pilot",
		},
	})
	require.NoError(t, err)
	require.True(t, ok)
	require.Equal(t, "<p>Pilot</p>", htmlBody)
}

func TestCatalogLookupFallsBackToEnglish(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "subject.tmpl"), "Your login code")
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "text.tmpl"), "Code: {{.code}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "subject.tmpl"), "Turn {{.turn_number}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "text.tmpl"), "Hello {{.player.name}}")

	catalog, err := NewCatalog(rootDir)
	require.NoError(t, err)

	locale, err := common.ParseLocale("fr-FR")
	require.NoError(t, err)
	resolved, err := catalog.Lookup(common.TemplateID("game.turn_ready"), locale)
	require.NoError(t, err)
	require.True(t, resolved.LocaleFallbackUsed())
	require.Equal(t, common.Locale("en"), resolved.ResolvedLocale())
}

func TestCatalogLookupRejectsMissingEnglishFallback(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "subject.tmpl"), "Your login code")
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "text.tmpl"), "Code: {{.code}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "fr-FR", "subject.tmpl"), "Tour {{.turn_number}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "fr-FR", "text.tmpl"), "Bonjour {{.player.name}}")

	catalog, err := NewCatalog(rootDir)
	require.NoError(t, err)

	locale, err := common.ParseLocale("de-DE")
	require.NoError(t, err)
	_, err = catalog.Lookup(common.TemplateID("game.turn_ready"), locale)
	require.Error(t, err)
	require.True(t, errors.Is(err, ErrFallbackMissing))
}

func TestCatalogLookupRejectsUnknownTemplateFamily(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "subject.tmpl"), "Your login code")
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "text.tmpl"), "Code: {{.code}}")

	catalog, err := NewCatalog(rootDir)
	require.NoError(t, err)

	locale, err := common.ParseLocale("en")
	require.NoError(t, err)
	_, err = catalog.Lookup(common.TemplateID("game.turn_ready"), locale)
	require.Error(t, err)
	require.True(t, errors.Is(err, ErrTemplateNotFound))
}

func TestCatalogAllowsTemplateWithoutHTML(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "subject.tmpl"), "Your login code")
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "text.tmpl"), "Code: {{.code}}")

	catalog, err := NewCatalog(rootDir)
	require.NoError(t, err)

	locale, err := common.ParseLocale("en")
	require.NoError(t, err)
	resolved, err := catalog.Lookup(common.TemplateID("auth.login_code"), locale)
	require.NoError(t, err)

	htmlBody, ok, err := resolved.ExecuteHTML(map[string]any{"code": "123456"})
	require.NoError(t, err)
	require.False(t, ok)
	require.Empty(t, htmlBody)
}

func TestCatalogVersionIsDeterministic(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "subject.tmpl"), "Your login code")
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "text.tmpl"), "Code: {{.code}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "subject.tmpl"), "Turn {{.turn_number}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "text.tmpl"), "Hello {{.player.name}}")

	firstCatalog, err := NewCatalog(rootDir)
	require.NoError(t, err)
	secondCatalog, err := NewCatalog(rootDir)
	require.NoError(t, err)

	locale, err := common.ParseLocale("en")
	require.NoError(t, err)
	firstResolved, err := firstCatalog.Lookup(common.TemplateID("game.turn_ready"), locale)
	require.NoError(t, err)
	secondResolved, err := secondCatalog.Lookup(common.TemplateID("game.turn_ready"), locale)
	require.NoError(t, err)

	require.Equal(t, firstResolved.Template().Version, secondResolved.Template().Version)
}

func TestNewCatalogRejectsMissingDirectory(t *testing.T) {
	t.Parallel()

	_, err := NewCatalog(filepath.Join(t.TempDir(), "missing"))
	require.Error(t, err)
	require.Contains(t, err.Error(), "stat root dir")
}

func TestNewCatalogRejectsMissingRequiredStartupTemplate(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "subject.tmpl"), "Turn {{.turn_number}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "text.tmpl"), "Hello {{.player.name}}")

	_, err := NewCatalog(rootDir)
	require.Error(t, err)
	require.Contains(t, err.Error(), `required template "auth.login_code" locale "en" is missing`)
}

func TestNewCatalogRejectsBrokenTemplateParse(t *testing.T) {
	t.Parallel()

	rootDir := t.TempDir()
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "subject.tmpl"), "Your login code")
	writeTemplateFile(t, rootDir, filepath.Join("auth.login_code", "en", "text.tmpl"), "Code: {{.code}}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "subject.tmpl"), "{{if .turn_number}")
	writeTemplateFile(t, rootDir, filepath.Join("game.turn_ready", "en", "text.tmpl"), "Hello {{.player.name}}")

	_, err := NewCatalog(rootDir)
	require.Error(t, err)
	require.True(t, errors.Is(err, ErrTemplateParseFailed))
}

func writeTemplateFile(t *testing.T, rootDir string, relativePath string, contents string) {
	t.Helper()

	absolutePath := filepath.Join(rootDir, relativePath)
	require.NoError(t, os.MkdirAll(filepath.Dir(absolutePath), 0o755))
	require.NoError(t, os.WriteFile(absolutePath, []byte(contents), 0o644))
}