/*
 * Iptv-Proxy is a project to proxyfie an m3u file and to proxyfie an Xtream iptv service (client API).
 * Copyright (C) 2020  Pierre-Emmanuel Jacquier
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package server

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
)

func (c *Config) getM3U(ctx *gin.Context) {
	ctx.Header("Content-Disposition", fmt.Sprintf(`attachment; filename=%q`, c.M3UFileName))
	ctx.Header("Content-Type", "application/octet-stream")

	ctx.File(c.proxyfiedM3UPath)
}

func (c *Config) reverseProxy(ctx *gin.Context) {
	rpURL, err := url.Parse(c.track.URI)
	if err != nil {
		ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
		return
	}

	c.stream(ctx, rpURL)
}

func (c *Config) stream(ctx *gin.Context, oriURL *url.URL) {
	id := ctx.Param("id")
	if strings.HasSuffix(id, ".m3u8") {
		c.hlsStream(ctx, oriURL)
		return
	}

	client := &http.Client{}

	req, err := http.NewRequest("GET", oriURL.String(), nil)
	if err != nil {
		ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
		return
	}

	req.Header.Set("User-Agent", ctx.Request.UserAgent())

	resp, err := client.Do(req)
	if err != nil {
		ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
		return
	}
	defer resp.Body.Close()

	copyHTTPHeader(ctx, resp.Header)
	ctx.Status(resp.StatusCode)
	ctx.Stream(func(w io.Writer) bool {
		io.Copy(w, resp.Body) // nolint: errcheck
		return false
	})
}

func (c *Config) hlsStream(ctx *gin.Context, oriURL *url.URL) {
	client := &http.Client{
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			return http.ErrUseLastResponse
		},
	}

	req, err := http.NewRequest("GET", oriURL.String(), nil)
	if err != nil {
		ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
		return
	}

	req.Header.Set("User-Agent", ctx.Request.UserAgent())

	resp, err := client.Do(req)
	if err != nil {
		ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusFound {
		location, err := resp.Location()
		if err != nil {
			ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
			return
		}
		id := ctx.Param("id")
		if strings.Contains(location.String(), id) {
			hlsChannelsRedirectURLLock.Lock()
			hlsChannelsRedirectURL[id] = *location
			hlsChannelsRedirectURLLock.Unlock()

			hlsReq, err := http.NewRequest("GET", location.String(), nil)
			if err != nil {
				ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
				return
			}

			hlsReq.Header.Set("User-Agent", ctx.Request.UserAgent())

			hlsResp, err := client.Do(hlsReq)
			if err != nil {
				ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
				return
			}
			defer hlsResp.Body.Close()

			b, err := ioutil.ReadAll(hlsResp.Body)
			if err != nil {
				ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
				return
			}
			body := string(b)
			body = strings.ReplaceAll(body, "/"+c.XtreamUser.String()+"/"+c.XtreamPassword.String()+"/", "/"+c.User.String()+"/"+c.Password.String()+"/")
			ctx.Data(http.StatusOK, hlsResp.Header.Get("Content-Type"), []byte(body))
			return
		}
		ctx.AbortWithError(http.StatusInternalServerError, errors.New("Unable to HLS stream")) // nolint: errcheck
		return
	}

	ctx.Status(resp.StatusCode)
}

func copyHTTPHeader(ctx *gin.Context, header http.Header) {
	for k, v := range header {
		ctx.Header(k, strings.Join(v, ", "))
	}
}

// authRequest handle auth credentials
type authRequest struct {
	Username string `form:"username" binding:"required"`
	Password string `form:"password" binding:"required"`
}

func (c *Config) authenticate(ctx *gin.Context) {
	var authReq authRequest
	if err := ctx.Bind(&authReq); err != nil {
		ctx.AbortWithError(http.StatusBadRequest, err) // nolint: errcheck
		return
	}
	if c.ProxyConfig.User.String() != authReq.Username || c.ProxyConfig.Password.String() != authReq.Password {
		ctx.AbortWithStatus(http.StatusUnauthorized)
	}
}

func (c *Config) appAuthenticate(ctx *gin.Context) {
	contents, err := ioutil.ReadAll(ctx.Request.Body)
	if err != nil {
		ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
		return
	}

	q, err := url.ParseQuery(string(contents))
	if err != nil {
		ctx.AbortWithError(http.StatusInternalServerError, err) // nolint: errcheck
		return
	}
	if len(q["username"]) == 0 || len(q["password"]) == 0 {
		ctx.AbortWithError(http.StatusBadRequest, fmt.Errorf("bad body url query parameters")) // nolint: errcheck
		return
	}
	log.Printf("[iptv-proxy] %v | %s |App Auth\n", time.Now().Format("2006/01/02 - 15:04:05"), ctx.ClientIP())
	if c.ProxyConfig.User.String() != q["username"][0] || c.ProxyConfig.Password.String() != q["password"][0] {
		ctx.AbortWithStatus(http.StatusUnauthorized)
	}

	ctx.Request.Body = ioutil.NopCloser(bytes.NewReader(contents))
}