// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// +build ignore

package main

import (
	"fmt"
	"html/template"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"sync"
)

const (
	url         = "https://hajimehoshi.github.io/ebiten/"
	licenseYear = 2013
)

var (
	examplesDir = filepath.Join("public", "examples")
	copyright   = fmt.Sprintf("© %d Hajime Hoshi", licenseYear)

	stableVersion = ""
	rcVersion     = ""
	devVersion    = ""
)

func majorMinor(ver string) string {
	t := strings.Split(ver, ".")
	return t[0] + "." + t[1]
}

func init() {
	b, err := exec.Command("git", "tag").Output()
	if err != nil {
		panic(err)
	}
	vers := strings.Split(strings.TrimSpace(string(b)), "\n")
	// TODO: Sort by a semantic version lib
	sort.Strings(vers)

	devVers := []string{}
	rcVers := []string{}
	stableVers := []string{}
	for _, ver := range vers {
		if strings.Index(ver, "-rc") != -1 {
			rcVers = append(rcVers, ver)
			continue
		}
		if strings.Index(ver, "-") != -1 {
			devVers = append(devVers, ver)
			continue
		}
		stableVers = append(stableVers, ver)
	}

	stableVersion = stableVers[len(stableVers)-1]
	rcVersion = rcVers[len(rcVers)-1]
	if majorMinor(rcVersion[:strings.Index(rcVersion, "-")]) == majorMinor(stableVersion) {
		rcVersion = ""
	}
	devVersion = devVers[len(devVers)-1]
}

func comment(text string) template.HTML {
	// http://www.w3.org/TR/html-markup/syntax.html#comments
	// The text part of comments has the following restrictions:
	// * must not start with a ">" character
	// * must not start with the string "->"
	// * must not contain the string "--"
	// * must not end with a "-" character

	for strings.HasPrefix(text, ">") {
		text = text[1:]
	}
	for strings.HasPrefix(text, "->") {
		text = text[2:]
	}
	text = strings.Replace(text, "--", "", -1)
	for strings.HasSuffix(text, "-") {
		text = text[:len(text)-1]
	}
	return template.HTML("<!--\n" + text + "\n-->")
}

func safeHTML(text string) template.HTML {
	return template.HTML(text)
}

type example struct {
	Name         string
	ThumbWidth   int
	ThumbHeight  int
	ScreenWidth  int
	ScreenHeight int
}

func (e *example) Width() int {
	if e.ScreenWidth == 0 {
		return e.ThumbWidth * 2
	}
	return e.ScreenWidth
}

func (e *example) Height() int {
	if e.ScreenHeight == 0 {
		return e.ThumbHeight * 2
	}
	return e.ScreenHeight
}

var (
	gamesExamples = []example{
		{Name: "2048", ThumbWidth: 210, ThumbHeight: 300},
		{Name: "blocks", ThumbWidth: 256, ThumbHeight: 240},
		{Name: "flappy", ThumbWidth: 320, ThumbHeight: 240},
	}
	graphicsExamples = []example{
		{Name: "airship", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "alphablending", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "animation", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "blur", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "drag", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "filter", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "flood", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "font", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "highdpi", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "hsv", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "hue", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "infinitescroll", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "life", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "mandelbrot", ThumbWidth: 320, ThumbHeight: 320, ScreenWidth: 640, ScreenHeight: 640},
		{Name: "masking", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "mosaic", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "noise", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "paint", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "perspective", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "polygons", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "raycasting", ThumbWidth: 240, ThumbHeight: 240},
		{Name: "rotate", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "sprites", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "tiles", ThumbWidth: 240, ThumbHeight: 240},
	}
	inputExamples = []example{
		{Name: "gamepad", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "keyboard", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "typewriter", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "wheel", ThumbWidth: 320, ThumbHeight: 240},
	}
	audioExamples = []example{
		{Name: "audio", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "piano", ThumbWidth: 320, ThumbHeight: 240},
		{Name: "sinewave", ThumbWidth: 320, ThumbHeight: 240},
	}
)

func clear() error {
	if err := filepath.Walk("public", func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if m, _ := regexp.MatchString("~$", path); m {
			return nil
		}
		// Remove auto-generated html files.
		m, err := regexp.MatchString(".html$", path)
		if err != nil {
			return err
		}
		if m {
			return os.Remove(path)
		}
		return nil
	}); err != nil {
		return err
	}
	return nil
}

func outputMain() error {
	f, err := os.Create("public/index.html")
	if err != nil {
		return err
	}
	defer f.Close()

	funcs := template.FuncMap{
		"comment":  comment,
		"safeHTML": safeHTML,
	}
	const templatePath = "index.tmpl.html"
	name := filepath.Base(templatePath)
	t, err := template.New(name).Funcs(funcs).ParseFiles(templatePath)
	if err != nil {
		return err
	}

	data := map[string]interface{}{
		"URL":              url,
		"Copyright":        copyright,
		"StableVersion":    stableVersion,
		"RCVersion":        rcVersion,
		"DevVersion":       devVersion,
		"GraphicsExamples": graphicsExamples,
		"InputExamples":    inputExamples,
		"AudioExamples":    audioExamples,
		"GamesExamples":    gamesExamples,
	}
	return t.Funcs(funcs).Execute(f, data)
}

func createExamplesDir() error {
	if err := os.RemoveAll(examplesDir); err != nil {
		return err
	}
	if err := os.MkdirAll(examplesDir, 0755); err != nil {
		return err
	}
	return nil
}

func outputExample(e *example) error {
	f, err := os.Create(filepath.Join(examplesDir, e.Name+".html"))
	if err != nil {
		return err
	}
	defer f.Close()

	funcs := template.FuncMap{
		"comment":  comment,
		"safeHTML": safeHTML,
	}
	const templatePath = "example.tmpl.html"
	name := filepath.Base(templatePath)
	t, err := template.New(name).Funcs(funcs).ParseFiles(templatePath)
	if err != nil {
		return err
	}

	data := map[string]interface{}{
		"URL":       url,
		"Copyright": copyright,
		"Example":   e,
	}
	return t.Funcs(funcs).Execute(f, data)
}

func main() {
	if err := clear(); err != nil {
		log.Fatal(err)
	}
	if err := outputMain(); err != nil {
		log.Fatal(err)
	}
	if err := createExamplesDir(); err != nil {
		log.Fatal(err)
	}

	examples := []example{}
	examples = append(examples, graphicsExamples...)
	examples = append(examples, inputExamples...)
	examples = append(examples, audioExamples...)
	examples = append(examples, gamesExamples...)

	wg := sync.WaitGroup{}
	for _, e := range examples {
		e := e
		wg.Add(1)
		go func() {
			defer wg.Done()
			if err := outputExample(&e); err != nil {
				log.Fatal(err)
			}
		}()
	}
	wg.Wait()
}