package main

import (
	"bytes"
	"encoding/json"
	"io/ioutil"
	"net/http"
	"time"

	"github.com/go-interpreter/wagon/wasm"
	"github.com/google/uuid"
	shell "github.com/ipfs/go-ipfs-api"
	"github.com/rogpeppe/go-internal/txtar"
	"tulpa.dev/within/wasmcloud/cmd/internal"
	"within.website/ln"
	"within.website/olin/namegen"
)

func createHandler(w http.ResponseWriter, r *http.Request, u *User) {
	if !u.CanCreateHandlers {
		http.Error(w, "you can't create handlers, contact support", http.StatusForbidden)
		return
	}

	ctx := r.Context()
	sh := shell.NewShell(*ipfsURL)
	data, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, 16*1024*1024))
	if err != nil {
		ln.Error(ctx, err)
		http.Error(w, "invalid data", http.StatusBadRequest)
		return
	}
	r.Body.Close()

	var hdlr internal.Handler
	err = json.Unmarshal(data, &hdlr)
	if err != nil {
		ln.Error(ctx, err)
		http.Error(w, "not json", http.StatusBadRequest)
		return
	}

	switch string(hdlr.ABI) {
	case string(internal.CWA), string(internal.Dagger):
	default:
		ln.Log(ctx, ln.Info("unknown ABI"), ln.F{"abi": hdlr.ABI})
		http.Error(w, "unknown ABI", http.StatusBadRequest)
		return
	}

	buf := bytes.NewBuffer(hdlr.WASM)
	_, err = wasm.DecodeModule(buf)
	if err != nil {
		ln.Error(ctx, err)
		http.Error(w, "not webassembly", http.StatusBadRequest)
	}

	cid, err := sh.Add(bytes.NewBuffer(hdlr.WASM))
	if err != nil {
		ln.Error(ctx, err)
		http.Error(w, "can't upload wasm to storage", http.StatusInternalServerError)
		return
	}

	n := namegen.Next()
	h := Handler{
		Name:   n,
		User:   *u,
		UserID: u.ID,
		Path:   cid,
	}

	if err := db.Save(&h).Error; err != nil {
		ln.Error(ctx, err)
		http.Error(w, "can't save record", http.StatusInternalServerError)
		return
	}

	json.NewEncoder(w).Encode(h)
}

func listHandlers(w http.ResponseWriter, r *http.Request, u *User) {
	ctx := r.Context()
	var hdlrs []Handler

	err := db.Where("user_id = ?", u.ID).Scan(&hdlrs).Error
	if err != nil {
		ln.Error(ctx, err)
		http.Error(w, "can't read handlers", http.StatusInternalServerError)
		return
	}

	json.NewEncoder(w).Encode(hdlrs)
}

func getLogs(w http.ResponseWriter, r *http.Request, u *User) {
	ctx := r.Context()
	q := r.URL.Query()
	name := q.Get("name")
	if name == "" {
		http.NotFound(w, r)
		return
	}

	var hdlr Handler
	err := db.Where("name = ? AND user_id = ?", name, u.ID).First(&hdlr).Error
	if err != nil {
		ln.Error(ctx, err)
		http.NotFound(w, r)
		return
	}

	var elogs []ExecutionLog
	err = db.Where("handler_id = ?", hdlr.ID).Find(&elogs).Error
	if err != nil {
		ln.Error(ctx, err)
		http.Error(w, "handler id not found", http.StatusInternalServerError)
		return
	}

	type resultLine struct {
		ExecID  string            `json:"exec_id"`
		Comment string            `json:"comment"`
		Logs    map[string]string `json:"logs"`
	}
	var result []resultLine

	for _, elog := range elogs {
		arc := txtar.Parse(elog.Data)
		logs := map[string]string{}

		for _, file := range arc.Files {
			logs[file.Name] = string(file.Data)
		}

		result = append(result, resultLine{
			ExecID:  elog.RunID,
			Comment: string(arc.Comment),
			Logs:    logs,
		})
	}

	json.NewEncoder(w).Encode(result)
}

func invokeHandler(w http.ResponseWriter, r *http.Request, u *User) {
	ctx := r.Context()
	q := r.URL.Query()
	name := q.Get("name")
	if name == "" {
		http.NotFound(w, r)
		return
	}

	var hdlr Handler
	err := db.Where("name = ?", name).First(&hdlr).Error
	if err != nil {
		ln.Error(ctx, err)
		http.NotFound(w, r)
		return
	}

	data, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, 1*1024*1024))
	if err != nil {
		ln.Error(ctx, err)
		http.NotFound(w, r)
	}

	execID := uuid.New().String()

	er := internal.ExecRequest{
		WASMCID: hdlr.Path,
		Name:    hdlr.Name,
		Data:    data,
		Env: map[string]string{
			"RUN_ID": execID,
		},
		UUID: execID,
	}

	encData, err := json.Marshal(er)
	if err != nil {
		ln.Error(ctx, err)
		http.NotFound(w, r)
	}

	go func() {
		msg, err := nc.Request(internal.TopicName, encData, 5*time.Minute)
		if err != nil {
			ln.Error(ctx, err)
			return
		}

		var resp internal.ExecResponse
		err = json.Unmarshal(msg.Data, &resp)
		if err != nil {
			ln.Error(ctx, err)
			return
		}

		data := txtar.Format(&resp.Logs)

		entry := ExecutionLog{
			HandlerID: hdlr.ID,
			RunID:     execID,
			Data:      data,
		}

		err = db.Save(&entry).Error
		if err != nil {
			ln.Error(ctx, err)
			return
		}
	}()
}