//go:build !js

package main

import (
	"context"
	goio "io"
	"path/filepath"
	"strings"
	"testing"
	"time"

	core "dappco.re/go/core"
	coreio "dappco.re/go/core/io"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestRun_WritesBundle_Good(t *testing.T) {
	input := core.NewReader(`{"H":"nav-bar","C":"main-content"}`)
	output := core.NewBuilder()

	err := run(input, output, false)
	require.NoError(t, err)

	js := output.String()
	assert.Contains(t, js, "NavBar")
	assert.Contains(t, js, "MainContent")
	assert.Contains(t, js, "customElements.define")
	assert.Equal(t, 2, countSubstr(js, "extends HTMLElement"))
}

func TestRun_InvalidJSON_Bad(t *testing.T) {
	input := core.NewReader(`not json`)
	output := core.NewBuilder()

	err := run(input, output, false)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "invalid JSON")
}

func TestRun_InvalidTag_Bad(t *testing.T) {
	input := core.NewReader(`{"H":"notag"}`)
	output := core.NewBuilder()

	err := run(input, output, false)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "hyphen")
}

func TestRun_InvalidTagCharacters_Bad(t *testing.T) {
	input := core.NewReader(`{"H":"Nav-Bar","C":"nav bar"}`)
	output := core.NewBuilder()

	err := run(input, output, false)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "lowercase hyphenated name")
}

func TestRun_EmptySlots_Good(t *testing.T) {
	input := core.NewReader(`{}`)
	output := core.NewBuilder()

	err := run(input, output, false)
	require.NoError(t, err)
	assert.Empty(t, output.String())
}

func TestRun_WritesTypeScriptDefinitions_Good(t *testing.T) {
	input := core.NewReader(`{"H":"nav-bar","C":"main-content"}`)
	output := core.NewBuilder()

	err := run(input, output, true)
	require.NoError(t, err)

	dts := output.String()
	assert.Contains(t, dts, "declare global")
	assert.Contains(t, dts, `"nav-bar": NavBar;`)
	assert.Contains(t, dts, `"main-content": MainContent;`)
	assert.Contains(t, dts, "export declare class NavBar extends HTMLElement")
	assert.Contains(t, dts, "export declare class MainContent extends HTMLElement")
}

func TestRunDaemon_WritesUpdatedBundle_Good(t *testing.T) {
	dir := t.TempDir()
	inputPath := filepath.Join(dir, "slots.json")
	outputPath := filepath.Join(dir, "bundle.js")

	require.NoError(t, writeTextFile(inputPath, `{"H":"nav-bar","C":"main-content"}`))

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	done := make(chan error, 1)
	go func() {
		done <- runDaemon(ctx, inputPath, outputPath, false, 5*time.Millisecond)
	}()

	require.Eventually(t, func() bool {
		got, err := readTextFile(outputPath)
		if err != nil {
			return false
		}
		return strings.Contains(got, "NavBar") && strings.Contains(got, "MainContent")
	}, time.Second, 10*time.Millisecond)

	cancel()
	require.NoError(t, <-done)
}

func TestRunDaemon_MissingPaths_Bad(t *testing.T) {
	err := runDaemon(context.Background(), "", "", false, time.Millisecond)
	require.Error(t, err)
	assert.Contains(t, err.Error(), "watch mode requires -input")
}

func countSubstr(s, substr string) int {
	if substr == "" {
		return len(s) + 1
	}

	count := 0
	for i := 0; i <= len(s)-len(substr); {
		j := indexSubstr(s[i:], substr)
		if j < 0 {
			return count
		}
		count++
		i += j + len(substr)
	}

	return count
}

func indexSubstr(s, substr string) int {
	if substr == "" {
		return 0
	}
	if len(substr) > len(s) {
		return -1
	}

	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return i
		}
	}

	return -1
}

func writeTextFile(path, content string) error {
	f, err := coreio.Local.Create(path)
	if err != nil {
		return err
	}
	defer func() {
		_ = f.Close()
	}()

	_, err = goio.WriteString(f, content)
	return err
}

func readTextFile(path string) (string, error) {
	f, err := coreio.Local.Open(path)
	if err != nil {
		return "", err
	}
	defer func() {
		_ = f.Close()
	}()

	data, err := goio.ReadAll(f)
	if err != nil {
		return "", err
	}
	return string(data), nil
}