// Now home to the parts of gen_router.go which aren't expected to change from generation to generation
package main

import (
	"log"
	"net/http"
	"os"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"time"

	c "git.tuxpa.in/a/gosora/common"
	co "git.tuxpa.in/a/gosora/common/counters"
)

// TODO: Stop spilling these into the package scope?
func init() {
    _ = time.Now()
    co.SetRouteMapEnum(routeMapEnum)
    co.SetReverseRouteMapEnum(reverseRouteMapEnum)
    co.SetAgentMapEnum(agentMapEnum)
    co.SetReverseAgentMapEnum(reverseAgentMapEnum)
    co.SetOSMapEnum(osMapEnum)
    co.SetReverseOSMapEnum(reverseOSMapEnum)

    g := func(n string) int {
        a, ok := agentMapEnum[n]
        if !ok {
            panic("name not found in agentMapEnum")
        }
        return a
    }
    c.Chrome = g("chrome")
    c.Firefox = g("firefox")
    c.SimpleBots = []int{
        g("semrush"),
        g("ahrefs"),
        g("python"),
        //g("go"),
        g("curl"),
    }
}

type WriterIntercept struct {
    http.ResponseWriter
}

func NewWriterIntercept(w http.ResponseWriter) *WriterIntercept {
    return &WriterIntercept{w}
}

var wiMaxAge = "max-age=" + strconv.Itoa(int(c.Day))

func (wi *WriterIntercept) WriteHeader(code int) {
    if code == 200 {
        h := wi.ResponseWriter.Header()
        h.Set("Cache-Control", wiMaxAge)
        h.Set("Vary", "Accept-Encoding")
    }
    wi.ResponseWriter.WriteHeader(code)
}

type GenRouter struct {
    UploadHandler func(http.ResponseWriter, *http.Request)
    extraRoutes   map[string]func(http.ResponseWriter, *http.Request, *c.User) c.RouteError

    reqLogger *log.Logger

    reqLog2 *RouterLog
    suspLog *RouterLog

    sync.RWMutex
}

type RouterLogLog struct {
    File *os.File
    Log  *log.Logger
}
type RouterLog struct {
    FileVal atomic.Value
    LogVal  atomic.Value

    sync.RWMutex
}

func (r *GenRouter) DailyTick() error {
    currentTime := time.Now()
    rotateLog := func(l *RouterLog, name string) error {
        l.Lock()
        defer l.Unlock()

        f := l.FileVal.Load().(*os.File)
        stat, e := f.Stat()
        if e != nil {
            return nil
        }
        if (stat.Size() < int64(c.Megabyte)) && (currentTime.Sub(c.StartTime).Hours() >= (24 * 7)) {
            return nil
        }
        if e = f.Close(); e != nil {
            return e
        }

        stimestr := strconv.FormatInt(currentTime.Unix(), 10)
        f, e = os.OpenFile(c.Config.LogDir+name+stimestr+".log", os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0755)
        if e != nil {
            return e
        }
        lval := log.New(f, "", log.LstdFlags)
        l.FileVal.Store(f)
        l.LogVal.Store(lval)
        return nil
    }

    if !c.Config.DisableSuspLog {
        err := rotateLog(r.suspLog, "reqs-susp-")
        if err != nil {
            return err
        }
    }
    return rotateLog(r.reqLog2, "reqs-")
}

type RouterConfig struct {
    Uploads     http.Handler
    DisableTick bool
}

func NewGenRouter(cfg *RouterConfig) (*GenRouter, error) {
    stimestr := strconv.FormatInt(c.StartTime.Unix(), 10)
    createLog := func(name, stimestr string) (*RouterLog, error) {
        f, err := os.OpenFile(c.Config.LogDir+name+"-"+stimestr+".log", os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0755)
        if err != nil {
            return nil, err
        }
        l := log.New(f, "", log.LstdFlags)
        var aVal atomic.Value
        var aVal2 atomic.Value
        aVal.Store(f)
        aVal2.Store(l)
        return &RouterLog{FileVal: aVal, LogVal: aVal2}, nil
    }
    reqLog, err := createLog("reqs", stimestr)
    if err != nil {
        return nil, err
    }
    var suspReqLog *RouterLog
    if !c.Config.DisableSuspLog {
        suspReqLog, err = createLog("reqs-susp", stimestr)
        if err != nil {
            return nil, err
        }
    }
    f3, err := os.OpenFile(c.Config.LogDir+"reqs-misc-"+stimestr+".log", os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0755)
    if err != nil {
        return nil, err
    }
    reqMiscLog := log.New(f3, "", log.LstdFlags)

    ro := &GenRouter{
        UploadHandler: func(w http.ResponseWriter, r *http.Request) {
            writ := NewWriterIntercept(w)
            http.StripPrefix("/uploads/", cfg.Uploads).ServeHTTP(writ, r)
        },
        extraRoutes: make(map[string]func(http.ResponseWriter, *http.Request, *c.User) c.RouteError),

        reqLogger: reqMiscLog,
        reqLog2:   reqLog,
        suspLog:   suspReqLog,
    }
    if !cfg.DisableTick {
        c.Tasks.Day.Add(ro.DailyTick)
    }
    return ro, nil
}

func (r *GenRouter) handleError(err c.RouteError, w http.ResponseWriter, req *http.Request, u *c.User) {
    if err.Handled() {
        return
    }
    if err.Type() == "system" {
        c.InternalErrorJSQ(err, w, req, err.JSON())
        return
    }
    c.LocalErrorJSQ(err.Error(), w, req, u, err.JSON())
}

func (r *GenRouter) Handle(_ string, _ http.Handler) {
}

func (r *GenRouter) HandleFunc(pattern string, h func(http.ResponseWriter, *http.Request, *c.User) c.RouteError) {
    r.Lock()
    defer r.Unlock()
    r.extraRoutes[pattern] = h
}

func (r *GenRouter) RemoveFunc(pattern string) error {
    r.Lock()
    defer r.Unlock()
    _, ok := r.extraRoutes[pattern]
    if !ok {
        return ErrNoRoute
    }
    delete(r.extraRoutes, pattern)
    return nil
}

func (r *GenRouter) dumpRequest(req *http.Request, pre string, log *RouterLog) {
    var sb strings.Builder
    r.ddumpRequest(req, pre, log, &sb)
}

// TODO: Some of these sanitisations may be redundant
var dumpReqLen = len("\nUA: \n Host: \nIP: \n") + 7
var dumpReqLen2 = len("\nHead : ") + 2

func (r *GenRouter) ddumpRequest(req *http.Request, pre string, l *RouterLog, sb *strings.Builder) {
    nfield := func(label, val string) {
        sb.WriteString(label)
        sb.WriteString(val)
    }
    field := func(label, val string) {
        nfield(label, c.SanitiseSingleLine(val))
    }
    ua := req.UserAgent()

    sb.Grow(dumpReqLen + len(pre) + len(ua) + len(req.Method) + len(req.Host) + (dumpReqLen2 * len(req.Header)))
    sb.WriteString(pre)
    sb.WriteString("\n")
    sb.WriteString(c.SanitiseSingleLine(req.Method))
    sb.WriteRune(' ')
    sb.WriteString(c.SanitiseSingleLine(req.URL.Path))
    field("\nUA: ", ua)

    for key, val := range req.Header {
        // Avoid logging this for security reasons
        if key == "Cookie" {
            continue
        }
        for _, vvalue := range val {
            sb.WriteString("\nHead ")
            sb.WriteString(c.SanitiseSingleLine(key))
            sb.WriteString(": ")
            sb.WriteString(c.SanitiseSingleLine(vvalue))
        }
    }
    field("\nHost: ", req.Host)
    if rawQuery := req.URL.RawQuery; rawQuery != "" {
        field("\nURL.RawQuery: ", rawQuery)
    }
    if ref := req.Referer(); ref != "" {
        field("\nRef: ", ref)
    }
    nfield("\nIP: ", req.RemoteAddr)
    sb.WriteString("\n")

    str := sb.String()
    l.RLock()
    l.LogVal.Load().(*log.Logger).Print(str)
    l.RUnlock()
}

func (r *GenRouter) DumpRequest(req *http.Request, pre string) {
    r.dumpRequest(req, pre, r.reqLog2)
}

func (r *GenRouter) unknownUA(req *http.Request) {
    if c.Dev.DebugMode {
        var presb strings.Builder
        presb.WriteString("Unknown UA: ")
        for _, ch := range req.UserAgent() {
            presb.WriteString(strconv.Itoa(int(ch)))
            presb.WriteRune(' ')
        }
        r.ddumpRequest(req, "", r.reqLog2, &presb)
    } else {
        r.reqLogger.Print("unknown ua: ", c.SanitiseSingleLine(req.UserAgent()))
    }
}

func (r *GenRouter) susp1(req *http.Request) bool {
    if !strings.Contains(req.URL.Path, ".") {
        return false
    }
    if strings.Contains(req.URL.Path, "..") /* || strings.Contains(req.URL.Path,"--")*/ {
        return true
    }
    lp := strings.ToLower(req.URL.Path)
    // TODO: Flag any requests which has a dot with anything but a number after that
    // TODO: Use HasSuffix to avoid over-scanning?
    return strings.Contains(lp, ".php") || strings.Contains(lp, ".asp") || strings.Contains(lp, ".cgi") || strings.Contains(lp, ".py") || strings.Contains(lp, ".sql") || strings.Contains(lp, ".act") //.action
}

func (r *GenRouter) suspScan(req *http.Request) {
    if c.Config.DisableSuspLog {
        if c.Dev.FullReqLog {
            r.DumpRequest(req, "")
        }
        return
    }

    // TODO: Cover more suspicious strings and at a lower layer than this
    var ch rune
    var susp bool
    for _, ch = range req.URL.Path { //char
        if ch != '&' && !(ch > 44 && ch < 58) && ch != '=' && ch != '?' && !(ch > 64 && ch < 91) && ch != '\\' && ch != '_' && !(ch > 96 && ch < 123) {
            susp = true
            break
        }
    }

    // Avoid logging the same request multiple times
    susp2 := r.susp1(req)
    if susp && susp2 {
        r.SuspiciousRequest(req, "Bad char '"+string(ch)+"' in path\nBad snippet in path")
    } else if susp {
        r.SuspiciousRequest(req, "Bad char '"+string(ch)+"' in path")
    } else if susp2 {
        r.SuspiciousRequest(req, "Bad snippet in path")
    } else if c.Dev.FullReqLog {
        r.DumpRequest(req, "")
    }
}

func isLocalHost(h string) bool {
    return h == "localhost" || h == "127.0.0.1" || h == "::1"
}

//var brPool = sync.Pool{}
var gzipPool = sync.Pool{}

//var uaBufPool = sync.Pool{}

func (r *GenRouter) responseWriter(w http.ResponseWriter) http.ResponseWriter {
    /*if bzw, ok := w.(c.BrResponseWriter); ok {
        w = bzw.ResponseWriter
        w.Header().Del("Content-Encoding")
    } else */if gzw, ok := w.(c.GzipResponseWriter); ok {
        w = gzw.ResponseWriter
        w.Header().Del("Content-Encoding")
    }
    return w
}