package main

import (
	"bytes"
	"database/sql"
	"database/sql/driver"
	"encoding/gob"
	"encoding/json"
	"errors"
	"gopkg.in/yaml.v3"
	"html/template"
	"io"
	"log"
	"net/http"
	"os"
	"os/exec"
	"sync"
	"time"

	"github.com/gorilla/sessions"
	"github.com/gorilla/websocket"
	"github.com/wader/gormstore/v2"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"zestack.dev/misc"
	"zestack.dev/slim"
)

const (
	// Time allowed to write a message to the peer.
	writeWait = 10 * time.Second

	// Time allowed to read the next pong message from the peer.
	pongWait = 60 * time.Second

	// Send pings to peer with this period. Must be less than pongWait.
	pingPeriod = (pongWait * 9) / 10

	// Maximum message size allowed from peer.
	maxMessageSize = 512
)

var (
	newline = []byte{'\n'}
	space   = []byte{' '}

	upgrader  *websocket.Upgrader
	clients   *sync.Map
	broadcast chan []byte

	store sessions.Store
	db    *gorm.DB
)

type NullString sql.NullString

// Scan implements the [Scanner] interface.
func (ns *NullString) Scan(value any) error {
	ss := new(sql.NullString)
	err := ss.Scan(value)
	ns.String = ss.String
	ns.Valid = ss.Valid
	return err
}

// Value implements the [driver.Valuer] interface.
func (ns NullString) Value() (driver.Value, error) {
	if !ns.Valid {
		return nil, nil
	}
	return ns.String, nil
}

func (ns NullString) MarshalJSON() ([]byte, error) {
	if ns.Valid {
		return json.Marshal(ns.String)
	}
	return json.Marshal(nil)
}

func (ns *NullString) UnmarshalJSON(b []byte) error {
	if string(b) == "null" {
		ns.Valid = false
		return nil
	}
	err := json.Unmarshal(b, &ns.String)
	if err == nil {
		ns.Valid = true
	}
	return err
}

type NullTime sql.NullTime

func (nt *NullTime) Scan(value any) error {
	st := new(sql.NullTime)
	err := st.Scan(value)
	nt.Time = st.Time
	nt.Valid = st.Valid
	return err
}

func (nt NullTime) Value() (driver.Value, error) {
	if !nt.Valid {
		return nil, nil
	}
	return nt.Time, nil
}

func (nt NullTime) MarshalJSON() ([]byte, error) {
	if nt.Valid {
		return nt.Time.MarshalJSON()
	}
	return json.Marshal(nil)
}

func (nt *NullTime) UnmarshalJSON(b []byte) error {
	if string(b) == "null" {
		nt.Valid = false
		return nil
	}
	err := json.Unmarshal(b, &nt.Time)
	if err == nil {
		nt.Valid = true
	}
	return err
}

type NullUint struct {
	V     uint
	Valid bool
}

func (nu *NullUint) Scan(value any) error {
	sn := new(sql.Null[uint])
	err := sn.Scan(value)
	nu.V = sn.V
	nu.Valid = sn.Valid
	return err
}

func (nu NullUint) Value() (driver.Value, error) {
	if !nu.Valid {
		return nil, nil
	}
	// 注意：driver.Value 不支持 uint
	return int64(nu.V), nil
}

func (nu NullUint) MarshalJSON() ([]byte, error) {
	if nu.Valid {
		return json.Marshal(nu.V)
	}
	return json.Marshal(nil)
}

func (nu *NullUint) UnmarshalJSON(b []byte) error {
	if string(b) == "null" {
		nu.Valid = false
		return nil
	}
	err := json.Unmarshal(b, &nu.V)
	if err == nil {
		nu.Valid = true
	}
	return err
}

// User 用户
type User struct {
	ID          uint      `json:"id" gorm:"primaryKey"`
	Username    string    `json:"username" gorm:"unique"`
	RawPassword string    `json:"-" gorm:"-"` // 原始密码
	Password    string    `json:"password"`
	Disabled    bool      `json:"disabled" gorm:"default:false"`
	CreatedAt   time.Time `json:"createdAt"`
	UpdatedAt   time.Time `json:"updatedAt"`
}

func (u *User) BeforeCreate(_ *gorm.DB) error {
	if u.RawPassword != "" {
		hash, err := misc.PasswordHash(u.RawPassword)
		if err != nil {
			return err
		}
		u.Password = hash
		return nil
	}
	return errors.New("缺少密码")
}

// Project 项目
type Project struct {
	// 项目编号，推荐使用 ObjectId 算法生成，也可以使用 UUID/NanoID 等。
	ID string `json:"id" gorm:"primaryKey"`
	// 项目名称
	Name string `json:"name" gorm:"unique"`
	// 项目介绍
	Intro string `json:"intro"`
	// 项目网站
	Website string `json:"website"`
	// 项目的仓库地址，比如 GitHub、Gitee、Gitlab、Gitea 或自建的仓库，
	// 如果是私有仓库，应该携带授权信息（建议使用私有令牌而不是账号密码）。
	RepositoryURL string `json:"repositoryURL"`
	// 用于构建的仓库分支，若置空则使用主分支
	Branch string `json:"branch"`
	// 创建项目的用户编号
	CreatedBy uint `json:"createdBy"`
	// 创建项目时的时间
	CreatedAt time.Time `json:"createdAt"`
	// 上一次修改项目信息的用户编号
	UpdatedBy NullUint `json:"updatedBy"`
	// 上一次修改项目信息的时间
	UpdatedAt NullTime `json:"updatedAt" gorm:"autoUpdateTime:false"`
}

// BuildStatus 构建状态
type BuildStatus string

const (
	BuildRunning BuildStatus = "running" // 正在运行
	BuildSuccess BuildStatus = "success" // 构建成功
	BuildFailure BuildStatus = "failure" // 构建失败
	BuildAborted BuildStatus = "aborted" // 构建中断
)

// Build 项目构建
type Build struct {
	// 构建编号
	ID string `json:"id" gorm:"primaryKey"`
	// 构建项目
	ProjectID string `json:"projectId"`
	// 关联项目，如果项目删除也删除
	Project *Project `json:"project,omitempty" gorm:"foreignKey:ProjectID;references:ID;constraint:OnUpdate:CASCADE,OnDelete:CASCADE"`
	// 构建时，项目最后一次提交的 commit 标识
	CommitId string `json:"commitId"`
	// 构建时，项目最后一次提交的 commit 信息
	CommitText string `json:"commitText"`
	// 非构建步骤失败时的错误信息
	Error NullString `json:"startedError"`
	// 启动构建程序的用户的编号，如果是通过 webhook 修改，会被置空
	StartedBy NullUint `json:"startedBy"`
	// 启动构建项目时的时间
	StartedAt time.Time `json:"startedAt"`
	// 手动停止或自动完成该项目构建时的时间
	StoppedAt NullTime `json:"stoppedAt"`
	// 手动停止该项目构建的用户的编号，自动完成会将该值置空。
	StoppedBy NullUint `json:"stoppedBy"`
	// 当前所处状态
	Status BuildStatus `json:"status"`

	// 步骤日志
	Logs []BuildLog `json:"logs"`

	// 创建构建步骤的用户编号，如果是通过 webhook 修改，会被置空
	CreatedBy NullUint `json:"createdBy"`
	// 创建构建步骤时的时间
	CreatedAt time.Time `json:"createdAt"`
	// 上一次修改构建步骤信息的用户编号，如果是通过 webhook 修改，会被置空
	UpdatedBy NullUint `json:"updatedBy"`
	// 上一次修改构建步骤信息的时间
	UpdatedAt NullTime `json:"updatedAt" gorm:"autoUpdateTime:false"`
}

// BuildLog 构建步骤日志
type BuildLog struct {
	// 日志编号
	Id uint `json:"id" gorm:"primaryKey"`
	// 归属的构建编号
	BuildID string `json:"buildId"`
	// 关联项目，如果项目删除也删除
	Build *Build `json:"build,omitempty" gorm:"foreignKey:BuildID;references:ID;constraint:OnUpdate:CASCADE,OnDelete:CASCADE"`
	// 构建步骤名称
	Name string `json:"name"`
	// 该构建步骤使用的程序
	Uses string `json:"uses"`
	// 该构建步骤时传递给程序的参数
	With map[string]string `json:"with" gorm:"serializer:json"`
	// 程序的运行日志
	Logs []string `json:"logs" gorm:"serializer:json"`
	// 当前所处状态
	Status BuildStatus `json:"status"`
	// 开始该步骤时的时间
	StartedAt time.Time `json:"startedAt"`
	// 结束该步骤时的时间
	StoppedAt time.Time `json:"stoppedAt"`
}

type BuildConfig struct {
	Name  string       `json:"name" yaml:"name"`
	VCS   VCSConfig    `json:"vcs" yaml:"vcs"`
	Steps []StepConfig `json:"steps" yaml:"steps"`
}

type VCSConfig struct {
	Branch string `json:"branch" yaml:"branch"`
}

type StepConfig struct {
	Name string            `json:"name" yaml:"name"`
	Uses string            `json:"uses" yaml:"uses"`
	With map[string]string `json:"with" yaml:"with"`
}

func Fail(c slim.Context, msg string, code ...int) error {
	statusCode := http.StatusBadRequest
	if len(code) > 0 {
		statusCode = code[0]
	}
	return c.JSON(statusCode, slim.Map{
		"ok":  false,
		"msg": msg,
	})
}

func AuthSession(c slim.Context, next slim.HandlerFunc) error {
	sess, err := store.Get(c.Request(), "session-key")
	if err != nil {
		return err
	}
	user, ok := sess.Values["user"].(*User)
	if !ok {
		return Fail(c, "请登录", http.StatusUnauthorized)
	}
	c.Set("user", user)
	return next(c)
}

func handleLogin(c slim.Context) error {
	var req struct {
		Username string `json:"username" form:"username"`
		Password string `json:"password" form:"password"`
	}
	if err := c.Bind(&req); err != nil {
		return err
	}
	if req.Username == "" {
		return c.Redirect(301, "/login?error=用户名不能为空")
	}
	if req.Password == "" {
		return c.Redirect(301, "/login?error=登录密码不能为空")
	}
	var user User
	err := db.Model(&User{}).Where("username", req.Username).First(&user).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return c.Redirect(301, "/login?error=用户名或密码错误")
		}
		return err
	}
	if !misc.PasswordVerify(req.Password, user.Password) {
		return c.Redirect(301, "/login?error=用户名或密码错误")
	}
	sess, err := store.Get(c.Request(), "session-key")
	if err != nil {
		return err
	}
	sess.Values["user"] = &user
	err = sess.Save(c.Request(), c.Response())
	if err != nil {
		return err
	}
	return c.Redirect(http.StatusMovedPermanently, "/")
}

func handleLogout(c slim.Context) error {
	// Get a session. We're ignoring the error resulted from decoding an
	// existing session: Get() always returns a session, even if empty.
	session, _ := store.Get(c.Request(), "session-name")
	// Set some session values.
	session.Values["foo"] = nil
	// Save it before we write to the response/return from the handler.
	err := session.Save(c.Request(), c.Response())
	if err != nil {
		return err
	}
	return c.Redirect(http.StatusMovedPermanently, "/")
}

func handleEcho(c slim.Context) error {
	conn, err := upgrader.Upgrade(c.Response(), c.Request(), nil)
	if err != nil {
		return err
	}

	clients.Store(conn, struct{}{})
	defer clients.Delete(conn)

	// TODO 使用 pool 实现复用
	exit := make(chan error)
	defer close(exit)

	stop := func(err error) {
		select {
		case <-exit:
		default:
			exit <- err
		}
	}

	go func() {
		conn.SetReadLimit(maxMessageSize)
		conn.SetReadDeadline(time.Now().Add(pongWait))
		conn.SetPongHandler(func(string) error {
			conn.SetReadDeadline(time.Now().Add(pongWait))
			return nil
		})
		for {
			_, message, ex := conn.ReadMessage()
			if ex != nil {
				if websocket.IsUnexpectedCloseError(ex, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
					stop(ex)
				} else {
					stop(nil)
				}
				return
			}
			message = bytes.TrimSpace(bytes.Replace(message, newline, space, -1))
			broadcast <- message
		}
	}()

	go func() {
		ticker := time.NewTicker(pingPeriod)
		defer func() {
			ticker.Stop()
			conn.Close()
		}()

		for {
			for {
				select {
				case message, ok := <-broadcast:
					conn.SetWriteDeadline(time.Now().Add(writeWait))
					if !ok {
						// The hub closed the channel.
						conn.WriteMessage(websocket.CloseMessage, []byte{})
						stop(nil)
						return
					}

					w, err2 := conn.NextWriter(websocket.TextMessage)
					if err2 != nil {
						stop(err2)
						return
					}
					w.Write(message)

					// Add queued chat messages to the current websocket message.
					n := len(broadcast)
					for i := 0; i < n; i++ {
						w.Write(newline)
						w.Write(<-broadcast)
					}

					if err3 := w.Close(); err3 != nil {
						stop(err3)
						return
					}
				case <-ticker.C:
					conn.SetWriteDeadline(time.Now().Add(writeWait))
					if err4 := conn.WriteMessage(websocket.PingMessage, nil); err4 != nil {
						stop(err4)
						return
					}
				}
			}
		}
	}()

	return <-exit
}

func handleStart(c slim.Context) error {
	cmd := exec.Command("go")
	cmd.Stdout = c.Response()
	cmd.Stderr = c.Response()
	cmd.Start()
	cmd.Wait()
	return nil
}

func handleAbort(c slim.Context) error {
	return c.String(200, "ok")
}

func handleHome(c slim.Context) error {
	return c.Render(http.StatusOK, "index.gohtml", "ws://"+c.Request().Host+"/echo")
}

type Template struct {
	templates *template.Template
}

func (t *Template) Render(c slim.Context, w io.Writer, name string, data any) error {
	return t.templates.ExecuteTemplate(w, name, data)
}

func main() {
	var err error
	db, err = gorm.Open(sqlite.Open("devops.db"), &gorm.Config{})
	if err != nil {
		log.Fatalln(err)
	}
	err = db.AutoMigrate(
		&User{},
		&Project{},
		&Build{},
		&BuildLog{},
	)
	if err != nil {
		log.Fatalln(err)
	}
	err = db.Model(&User{}).FirstOrCreate(&User{
		ID:          1,
		Username:    "admin",
		RawPassword: "111111",
	}, User{ID: 1}).Error
	if err != nil {
		log.Fatalln(err)
	}

	upgrader = &websocket.Upgrader{}
	clients = new(sync.Map)
	broadcast = make(chan []byte)
	store = gormstore.New(db, []byte("secret"))

	gob.Register(&User{})

	s := slim.New()
	s.Debug = true
	s.Renderer = &Template{templates: template.Must(template.ParseGlob("views/*.gohtml"))}
	s.Use(slim.Logging())
	s.Use(slim.Recovery())
	s.Use(slim.Static("public"))

	s.File("/login", "login.html")
	s.POST("/login", handleLogin)
	s.GET("/logout", handleLogout)
	s.GET("/echo", handleEcho)
	s.GET("/", handleHome)
	s.Route("/p/", func(sub slim.RouteCollector) {
		sub.Use(AuthSession)
		sub.POST(":id/start", handleStart)
		sub.POST(":id/abort", handleAbort)
		sub.GET("*", handleStart)
	})

	s.GET("/~", func(c slim.Context) error {
		file, err := os.ReadFile("deploy.yml")
		if err != nil {
			return err
		}

		var config BuildConfig
		err = yaml.Unmarshal(file, &config)
		if err != nil {
			return err
		}

		return c.JSONPretty(200, config, "  ")
	})

	//http.HandleFunc("/echo", handleWebsocket)
	//http.HandleFunc("/restart", restart)
	//http.ListenAndServe(":5000", nil)
	log.Fatalln(s.Start(":5000"))
}