// WRP ISMAP / ChromeDP routines
package main

import (
	"bytes"
	"context"
	"fmt"
	"image"
	"image/gif"
	"image/jpeg"
	"image/png"
	"io"
	"log"
	"math"
	"math/rand"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/chromedp/cdproto/css"
	"github.com/chromedp/cdproto/emulation"
	"github.com/chromedp/cdproto/input"
	"github.com/chromedp/cdproto/page"
	"github.com/chromedp/chromedp"
)

func chromedpStart() (context.CancelFunc, context.CancelFunc) {
	opts := append(chromedp.DefaultExecAllocatorOptions[:],
		chromedp.Flag("headless", *headless),
		chromedp.Flag("hide-scrollbars", false),
		chromedp.Flag("enable-automation", false),
		chromedp.Flag("disable-blink-features", "AutomationControlled"),
	)
	if *userAgent != "" {
		opts = append(opts, chromedp.UserAgent(*userAgent))
	}
	actx, acncl = chromedp.NewExecAllocator(context.Background(), opts...)
	ctx, cncl = chromedp.NewContext(actx)
	return cncl, acncl
}

// Determine what action to take
func (rq *wrpReq) action() chromedp.Action {
	// Mouse Click
	if rq.mouseX > 0 && rq.mouseY > 0 {
		log.Printf("%s Mouse Click %d,%d\n", rq.r.RemoteAddr, rq.mouseX, rq.mouseY)
		return chromedp.MouseClickXY(float64(rq.mouseX)/float64(rq.zoom), float64(rq.mouseY)/float64(rq.zoom))
	}
	// Buttons
	if len(rq.buttons) > 0 {
		log.Printf("%s Button %v\n", rq.r.RemoteAddr, rq.buttons)
		switch rq.buttons {
		case "Bk":
			return chromedp.NavigateBack()
		case "St":
			return chromedp.Stop()
		case "Re":
			return chromedp.Reload()
		case "Bs":
			return chromedp.KeyEvent("\b")
		case "Rt":
			return chromedp.KeyEvent("\r")
		case "<":
			return chromedp.KeyEvent("\u0302")
		case "^":
			return chromedp.KeyEvent("\u0304")
		case "v":
			return chromedp.KeyEvent("\u0301")
		case ">":
			return chromedp.KeyEvent("\u0303")
		case "Up":
			return chromedp.KeyEvent("\u0308")
		case "Dn":
			return chromedp.KeyEvent("\u0307")
		case "All": // Select all
			return chromedp.KeyEvent("a", chromedp.KeyModifiers(input.ModifierCtrl))
		}
	}
	// Keys
	if len(rq.keys) > 0 {
		log.Printf("%s Sending Keys: %#v\n", rq.r.RemoteAddr, rq.keys)
		return chromedp.KeyEvent(rq.keys)
	}
	// Navigate to URL
	log.Printf("%s Processing Navigate Request for %s\n", rq.r.RemoteAddr, rq.url)
	return chromedp.Navigate(rq.url)
}

// Navigate to the desired URL.
func (rq *wrpReq) navigate() {
	ctxErr(chromedp.Run(ctx, rq.action()), rq.w)
}

// Handle context errors
func ctxErr(err error, w io.Writer) {
	// TODO: callers should have retry logic, perhaps create another function
	// that takes ...chromedp.Action and retries with give up
	if err == nil {
		return
	}
	log.Printf("Context error: %s", err)
	fmt.Fprintf(w, "Context error: %s<BR>\n", err)
	if err.Error() != "context canceled" {
		return
	}
	ctx, cncl = chromedp.NewContext(actx)
	log.Printf("Created new context, try again")
	fmt.Fprintln(w, "Created new context, try again")
}

// https://github.com/chromedp/chromedp/issues/979
func chromedpCaptureScreenshot(res *[]byte, h int64) chromedp.Action {
	if res == nil {
		panic("res cannot be nil") // TODO: do not panic here, return error
	}
	if h == 0 {
		return chromedp.CaptureScreenshot(res)
	}

	return chromedp.ActionFunc(func(ctx context.Context) error {
		var err error
		*res, err = page.CaptureScreenshot().Do(ctx)
		return err
	})
}

// Capture Screenshot using CDP
func (rq *wrpReq) captureScreenshot() {
	var styles []*css.ComputedStyleProperty
	var r, g, b int
	var bgColorSet bool
	var h int64
	var pngCap []byte
	chromedp.Run(ctx,
		emulation.SetDeviceMetricsOverride(int64(float64(rq.width)/rq.zoom), 10, rq.zoom, false),
		chromedp.Location(&rq.url),
		chromedp.ComputedStyle("body", &styles, chromedp.ByQuery),
		chromedp.ActionFunc(func(ctx context.Context) error {
			_, _, _, _, _, s, err := page.GetLayoutMetrics().Do(ctx)
			if err == nil {
				h = int64(math.Ceil(s.Height))
			}
			return nil
		}),
	)
	log.Printf("%s Landed on: %s, Height: %v\n", rq.r.RemoteAddr, rq.url, h)
	for _, style := range styles {
		if style.Name != "background-color" {
			continue
		}
		fmt.Sscanf(style.Value, "rgb(%d,%d,%d)", &r, &g, &b)
		bgColorSet = true
		break
	}
	if !bgColorSet {
		r = 255
		g = 255
		b = 255
	}
	height := int64(float64(rq.height) / rq.zoom)
	if rq.height == 0 && h > 0 {
		height = h + 30
	}
	chromedp.Run(
		ctx, emulation.SetDeviceMetricsOverride(int64(float64(rq.width)/rq.zoom), height, rq.zoom, false),
		chromedp.Sleep(*delay), // TODO(tenox): find a better way to determine if page is rendered
	)
	// Capture screenshot...
	ctxErr(chromedp.Run(ctx, chromedpCaptureScreenshot(&pngCap, rq.height)), rq.w)
	seq := rand.Intn(9999)
	imgPath := fmt.Sprintf("/img/%04d.%s", seq, rq.imgType)
	mapPath := fmt.Sprintf("/map/%04d.map", seq)
	ismap[mapPath] = *rq
	var sSize string
	var iW, iH int
	switch rq.imgType {
	case "png":
		pngBuf := bytes.NewBuffer(pngCap)
		img[imgPath] = *pngBuf
		cfg, _, _ := image.DecodeConfig(pngBuf)
		sSize = fmt.Sprintf("%.0f KB", float32(len(pngBuf.Bytes()))/1024.0)
		iW = cfg.Width
		iH = cfg.Height
		log.Printf("%s Got PNG image: %s, Size: %s, Res: %dx%d\n", rq.r.RemoteAddr, imgPath, sSize, iW, iH)
	case "gif":
		i, err := png.Decode(bytes.NewReader(pngCap))
		if err != nil {
			log.Printf("%s Failed to decode PNG screenshot: %s\n", rq.r.RemoteAddr, err)
			fmt.Fprintf(rq.w, "<BR>Unable to decode page PNG screenshot:<BR>%s<BR>\n", err)
			return
		}
		st := time.Now()
		var gifBuf bytes.Buffer
		err = gif.Encode(&gifBuf, gifPalette(i, rq.imgOpt), &gif.Options{})
		if err != nil {
			log.Printf("%s Failed to encode GIF: %s\n", rq.r.RemoteAddr, err)
			fmt.Fprintf(rq.w, "<BR>Unable to encode GIF:<BR>%s<BR>\n", err)
			return
		}
		img[imgPath] = gifBuf
		sSize = fmt.Sprintf("%.0f KB", float32(len(gifBuf.Bytes()))/1024.0)
		iW = i.Bounds().Max.X
		iH = i.Bounds().Max.Y
		log.Printf("%s Encoded GIF image: %s, Size: %s, Colors: %d, Res: %dx%d, Time: %vms\n", rq.r.RemoteAddr, imgPath, sSize, rq.imgOpt, iW, iH, time.Since(st).Milliseconds())
	case "jpg":
		i, err := png.Decode(bytes.NewReader(pngCap))
		if err != nil {
			log.Printf("%s Failed to decode PNG screenshot: %s\n", rq.r.RemoteAddr, err)
			fmt.Fprintf(rq.w, "<BR>Unable to decode page PNG screenshot:<BR>%s<BR>\n", err)
			return
		}
		st := time.Now()
		var jpgBuf bytes.Buffer
		err = jpeg.Encode(&jpgBuf, i, &jpeg.Options{Quality: *jpgQual})
		if err != nil {
			log.Printf("%s Failed to encode JPG: %s\n", rq.r.RemoteAddr, err)
			fmt.Fprintf(rq.w, "<BR>Unable to encode JPG:<BR>%s<BR>\n", err)
			return
		}
		img[imgPath] = jpgBuf
		sSize = fmt.Sprintf("%.0f KB", float32(len(jpgBuf.Bytes()))/1024.0)
		iW = i.Bounds().Max.X
		iH = i.Bounds().Max.Y
		log.Printf("%s Encoded JPG image: %s, Size: %s, Quality: %d, Res: %dx%d, Time: %vms\n", rq.r.RemoteAddr, imgPath, sSize, *jpgQual, iW, iH, time.Since(st).Milliseconds())
	}
	rq.printUI(uiParams{
		bgColor:    fmt.Sprintf("#%02X%02X%02X", r, g, b),
		pageHeight: fmt.Sprintf("%d PX", h),
		imgSize:    sSize,
		imgURL:     imgPath,
		mapURL:     mapPath,
		imgWidth:   iW,
		imgHeight:  iH,
	})
	log.Printf("%s Done with capture for %s\n", rq.r.RemoteAddr, rq.url)
}

func mapServer(w http.ResponseWriter, r *http.Request) {
	log.Printf("%s ISMAP Request for %s [%+v]\n", r.RemoteAddr, r.URL.Path, r.URL.RawQuery)
	rq, ok := ismap[r.URL.Path]
	rq.r = r
	rq.w = w
	if !ok {
		fmt.Fprintf(w, "Unable to find map %s\n", r.URL.Path)
		log.Printf("Unable to find map %s\n", r.URL.Path)
		return
	}
	if !*noDel {
		defer delete(ismap, r.URL.Path)
	}
	n, err := fmt.Sscanf(r.URL.RawQuery, "%d,%d", &rq.mouseX, &rq.mouseY)
	if err != nil || n != 2 {
		fmt.Fprintf(w, "n=%d, err=%s\n", n, err)
		log.Printf("%s ISMAP n=%d, err=%s\n", r.RemoteAddr, n, err)
		return
	}
	log.Printf("%s WrpReq from ISMAP: %+v\n", r.RemoteAddr, rq)
	if len(rq.url) < 4 {
		rq.printUI(uiParams{bgColor: "#FFFFFF"})
		return
	}
	rq.navigate() // TODO: if error from navigate do not capture
	rq.captureScreenshot()
}

// TODO: merge this with html mode IMGZ
func imgServerMap(w http.ResponseWriter, r *http.Request) {
	log.Printf("%s IMG Request for %s\n", r.RemoteAddr, r.URL.Path)
	imgBuf, ok := img[r.URL.Path]
	if !ok || imgBuf.Bytes() == nil {
		fmt.Fprintf(w, "Unable to find image %s\n", r.URL.Path)
		log.Printf("%s Unable to find image %s\n", r.RemoteAddr, r.URL.Path)
		return
	}
	if !*noDel {
		defer delete(img, r.URL.Path)
	}
	switch {
	case strings.HasSuffix(r.URL.Path, ".gif"):
		w.Header().Set("Content-Type", "image/gif")
	case strings.HasSuffix(r.URL.Path, ".png"):
		w.Header().Set("Content-Type", "image/png")
	case strings.HasSuffix(r.URL.Path, ".jpg"):
		w.Header().Set("Content-Type", "image/jpeg")
	}
	w.Header().Set("Content-Length", strconv.Itoa(len(imgBuf.Bytes())))
	w.Header().Set("Cache-Control", "max-age=0")
	w.Header().Set("Expires", "-1")
	w.Header().Set("Pragma", "no-cache")
	w.Write(imgBuf.Bytes())
	w.(http.Flusher).Flush()
}