package main

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"
	"syscall"
	"time"

	"golang.org/x/crypto/ssh"
)

type CommandState string

type CommandStatus struct {
	Command string       `json:"command"`
	State   CommandState `json:"state"`
}

type Status struct {
	Commit   *Commit         `json:"commit"`
	Commands []CommandStatus `json:"commands"`
}

type Server struct {
	l  sync.Locker
	hs *http.Server
	// TODO(gio): randomly generate string
	runId       int
	agentMode   bool
	port        int
	appId       string
	service     string
	id          string
	ready       bool
	cmd         *exec.Cmd
	repoAddr    string
	branch      string
	rootDir     string
	signer      ssh.Signer
	appDir      string
	runCommands []Command
	self        string
	managerAddr string
	logs        *Logger
	logM        io.Writer
	currDir     string
	status      *Status
	stop        bool
}

func NewServer(agentMode bool, port int, appId, service, id, repoAddr, branch, rootDir string, signer ssh.Signer, appDir string, runCommands []Command, self string, manager string) *Server {
	logger := NewLogger("0")
	logM := io.MultiWriter(os.Stdout, logger)
	return &Server{
		l:           &sync.Mutex{},
		hs:          nil,
		runId:       0,
		agentMode:   agentMode,
		port:        port,
		ready:       false,
		appId:       appId,
		service:     service,
		id:          id,
		repoAddr:    repoAddr,
		branch:      branch,
		rootDir:     rootDir,
		signer:      signer,
		appDir:      appDir,
		runCommands: runCommands,
		self:        self,
		managerAddr: manager,
		logs:        logger,
		logM:        logM,
		currDir:     "",
		status:      nil,
		stop:        false,
	}
}

func (s *Server) Start() error {
	http.HandleFunc("/update", s.handleUpdate)
	http.HandleFunc("/ready", s.handleReady)
	http.HandleFunc("/logs", s.handleLogs)
	http.HandleFunc("/quitquitquit", s.handleQuit)
	if s.managerAddr != "" && s.appId != "" {
		go s.pingManager()
	}
	if err := s.run(); err != nil {
		return err
	}
	hs := &http.Server{
		Addr: fmt.Sprintf(":%d", s.port),
	}
	s.hs = hs
	if err := s.hs.ListenAndServe(); err == nil || errors.Is(err, http.ErrServerClosed) {
		return nil
	} else {
		return err
	}
}

func (s *Server) Stop() {
	fmt.Println("Stopping")
	s.l.Lock()
	defer s.l.Unlock()
	s.stop = true
	if err := s.kill(); err != nil {
		fmt.Printf("Failed to stop last command: %s\n", err)
	} else {
		fmt.Println("Stopped last command")
	}
	if s.hs != nil {
		if err := s.hs.Shutdown(context.Background()); err != nil {
			fmt.Printf("Failed to stop web server: %s\n", err)
		} else {
			fmt.Println("Stopped web server")
		}
	}
}

func (s *Server) handleQuit(w http.ResponseWriter, r *http.Request) {
	go s.Stop()
}

func (s *Server) handleLogs(w http.ResponseWriter, r *http.Request) {
	if logs, err := s.logs.Contents(); err != nil {
		http.Error(w, "not ready", http.StatusInternalServerError)
	} else {
		fmt.Fprint(w, logs)
	}
}

func (s *Server) handleReady(w http.ResponseWriter, r *http.Request) {
	s.l.Lock()
	defer s.l.Unlock()
	if s.ready {
		fmt.Fprintln(w, "ok")
	} else {
		http.Error(w, "not ready", http.StatusInternalServerError)
	}
}

func (s *Server) log(tmpl string, args ...any) {
	contents := fmt.Sprintf(tmpl, args...)
	fmt.Fprintf(s.logs, "\033[38;5;212;136;141mdodo:\033[0;00m %s\n", contents)
}

func (s *Server) handleUpdate(w http.ResponseWriter, r *http.Request) {
	s.l.Lock()
	s.ready = false
	s.l.Unlock()
	s.log("Reloading service")
	if err := s.run(); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	s.l.Lock()
	s.ready = true
	s.l.Unlock()
}

type command struct {
	cmd string
	env []string
}

func (s *Server) run() error {
	newDir := s.appDir
	commands := []command{}
	if !s.agentMode {
		var err error
		newDir, err = os.MkdirTemp(s.appDir, "code-*")
		if err != nil {
			return err
		}
	}
	if s.repoAddr != "" {
		if _, err := os.Stat(filepath.Join(newDir, ".git")); err != nil && os.IsNotExist(err) {
			commit, err := CloneRepositoryBranch(s.repoAddr, s.branch, s.rootDir, s.signer, newDir)
			if err != nil {
				s.log("Failed to clone repository: %s", err)
				s.status = &Status{
					Commit: nil,
				}
				return err
			}
			s.log("Successfully cloned repository %s", commit.Hash)
			s.status = &Status{
				Commit:   commit,
				Commands: []CommandStatus{},
			}
		} else {
			s.status = &Status{
				Commands: []CommandStatus{},
			}
		}
	} else {
		s.status = &Status{
			Commit:   nil,
			Commands: []CommandStatus{},
		}
	}
	if s.status.Commit != nil {
		s.logs.commitHash = s.status.Commit.Hash
	} else {
		s.logs.commitHash = ""
	}
	if s.agentMode && s.repoAddr == "" {
		if _, err := os.Stat(filepath.Join(newDir, ".git")); err != nil && os.IsNotExist(err) {
			commands = append(commands, command{cmd: "git config --global user.name dodo"})
			s.status.Commands = append(s.status.Commands, CommandStatus{
				Command: commands[len(commands)-1].cmd,
				State:   "waiting",
			})
			commands = append(commands, command{cmd: "git config --global user.email dodo@dodo.cloud"})
			s.status.Commands = append(s.status.Commands, CommandStatus{
				Command: commands[len(commands)-1].cmd,
				State:   "waiting",
			})
			commands = append(commands, command{cmd: "git init ."})
			s.status.Commands = append(s.status.Commands, CommandStatus{
				Command: commands[len(commands)-1].cmd,
				State:   "waiting",
			})
			commands = append(commands, command{cmd: "echo \"TODO: Describe project\" > README.md"})
			s.status.Commands = append(s.status.Commands, CommandStatus{
				Command: commands[len(commands)-1].cmd,
				State:   "waiting",
			})
			commands = append(commands, command{cmd: "git add README.md"})
			s.status.Commands = append(s.status.Commands, CommandStatus{
				Command: commands[len(commands)-1].cmd,
				State:   "waiting",
			})
			commands = append(commands, command{cmd: "git commit -m \"init\""})
			s.status.Commands = append(s.status.Commands, CommandStatus{
				Command: commands[len(commands)-1].cmd,
				State:   "waiting",
			})
		}
	}
	for _, c := range s.runCommands {
		args := []string{c.Bin}
		args = append(args, c.Args...)
		cmd := strings.Join(args, " ")
		commands = append(commands, command{cmd, c.Env})
		s.status.Commands = append(s.status.Commands, CommandStatus{
			Command: cmd,
			State:   "waiting",
		})
	}
	for i, c := range commands {
		if i > 0 {
			s.status.Commands[i-1].State = "success"
		}
		cmd := &exec.Cmd{
			Dir:    filepath.Join(newDir, s.rootDir),
			Path:   "/bin/sh",
			Args:   []string{"/bin/sh", "-c", c.cmd},
			Env:    append(os.Environ(), c.env...),
			Stdout: s.logM,
			Stderr: s.logM,
		}
		cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
		s.log("Running: %s", c)
		s.status.Commands[i].State = "running"
		if i < len(commands)-1 {
			if err := cmd.Run(); err != nil {
				return err
			}
		} else {
			if s.cmd != nil {
				// TODO(gio): make this point configurable
				if err := s.kill(); err != nil {
					return err
				}
				if s.currDir != "" && !s.agentMode {
					if err := os.RemoveAll(s.currDir); err != nil {
						return err
					}
				}
			}
			if err := cmd.Start(); err != nil {
				return err
			}
			s.cmd = cmd
		}
	}
	s.currDir = newDir
	return nil
}

type pingReq struct {
	Id      string    `json:"id"`
	Service string    `json:"service"`
	Address string    `json:"address"`
	Status  *Status   `json:"status,omitempty"`
	Logs    []LogItem `json:"logs"`
}

type pingResp struct {
	Success          bool `json:"success"`
	LogItemsConsumed int  `json:"logItemsConsumed"`
}

func min(a, b int) int {
	if a < b {
		return a
	} else {
		return b
	}
}

func (s *Server) pingManager() {
	defer func() {
		go func() {
			s.l.Lock()
			defer s.l.Unlock()
			// TODO(gio): Wait until all logs are sent over to the manager.
			if !s.stop {
				time.Sleep(1 * time.Second)
				s.pingManager()
			}
		}()
	}()
	logItems := s.logs.Items()
	logItems = logItems[:min(100, len(logItems))]
	buf, err := json.Marshal(pingReq{
		Id:      s.id,
		Service: s.service,
		Address: fmt.Sprintf("http://%s:%d", s.self, s.port),
		Status:  s.status,
		Logs:    logItems,
	})
	if err != nil {
		return
	}
	registerWorkerAddr := fmt.Sprintf("%s/api/project/%s/workers", s.managerAddr, s.appId)
	resp, err := http.Post(registerWorkerAddr, "application/json", bytes.NewReader(buf))
	if err != nil {
		fmt.Println(err)
	} else {
		var r pingResp
		if err := json.NewDecoder(resp.Body).Decode(&r); err != nil {
			fmt.Printf("%s\n", err)
		} else if r.Success {
			s.logs.Trim(r.LogItemsConsumed)
		}
	}
}

func (s *Server) kill() error {
	if s.cmd == nil {
		return nil
	}

	err := syscall.Kill(-s.cmd.Process.Pid, syscall.SIGKILL)
	if err != nil {
		return err
	}
	// NOTE(gio): No need to check err as we just killed the process
	s.cmd.Wait()
	s.cmd = nil
	return nil
}