package routes

import (
	"context"
	"filething/db"
	"filething/models"
	"fmt"
	"net/http"
	"os"
	"regexp"
	"runtime"
	"strconv"
	"time"

	"github.com/dustin/go-humanize"
	"github.com/gofiber/fiber/v3"
	"github.com/google/uuid"
	"golang.org/x/crypto/bcrypt"
)

func GetUsers(c fiber.Ctx) error {
	db := db.GetDB()

	count, err := db.NewSelect().Model((*models.User)(nil)).Count(context.Background())

	if err != nil {
		fmt.Println(err)
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "Invalid page number"})
	}

	// this should be a query param not a URL param
	pageStr := c.Query("page")
	if pageStr == "" {
		pageStr = "0"
	}

	page, err := strconv.Atoi(pageStr)
	if err != nil {
		page = 0
	}

	offset := page * 30
	limit := 30

	if offset > count {
		return c.Status(http.StatusBadRequest).JSON(fiber.Map{"message": "Invalid page number"})
	}

	var users []models.User
	err = db.NewSelect().
		Model(&users).
		Limit(limit).
		Offset(offset).
		Order("created_at ASC").
		Scan(context.Background())
	if err != nil {
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "Failed to retrieve users"})
	}

	if users == nil {
		return c.Status(http.StatusBadRequest).JSON(fiber.Map{"message": "Invalid page number"})
	}

	return c.Status(http.StatusOK).JSON(fiber.Map{"users": users, "total_users": count})
}

type UserEdit struct {
	Username string `json:"username"`
	Email    string `json:"email"`
	Password string `json:"password"`
	PlanID   int64  `json:"plan_id"`
	Admin    bool   `json:"is_admin"`
}

func EditUser(c fiber.Ctx) error {
	db := db.GetDB()
	id := c.Params("id")

	userEditData := new(UserEdit)
	if err := c.Bind().JSON(userEditData); err != nil {
		fmt.Println(err)
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	if !regexp.MustCompile(`^[a-z0-9._%+\-]+@[a-z0-9.\-]+\.[a-z]{2,4}$`).MatchString(userEditData.Email) {
		return c.Status(http.StatusBadRequest).JSON(fiber.Map{"message": "A valid email is required!"})
	}

	plan := models.Plan{
		ID: userEditData.PlanID,
	}
	planCount, err := db.NewSelect().Model(&plan).WherePK().Count(context.Background())
	if err != nil || planCount == 0 {
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "Invalid plan id!"})
	}

	userId, err := uuid.Parse(id)
	if err != nil {
		return c.Status(http.StatusBadRequest).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	var userData models.User
	userData.ID = userId

	err = db.NewSelect().Model(&userData).WherePK().Relation("Plan").Scan(context.Background())
	if err != nil {
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	if userEditData.Username != "" {
		userData.Username = userEditData.Username
	}

	if userEditData.Email != "" {
		userData.Email = userEditData.Email
	}

	if userEditData.Password != "" {
		hash, err := bcrypt.GenerateFromPassword([]byte(userEditData.Password), 12)
		if err != nil {
			return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "An unknown error occoured!"})
		}

		userData.PasswordHash = string(hash)
	}

	if userEditData.PlanID != 0 {
		userData.PlanID = userEditData.PlanID
	}

	userData.Admin = userEditData.Admin

	// update the user, but, if the password is empty, but dont use OmitZero because it will ignore is_admin if it's false
	_, err = db.NewUpdate().Model(&userData).WherePK().Exec(context.Background())
	if err != nil {
		fmt.Println(err)
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	return c.Status(http.StatusOK).JSON(fiber.Map{"message": "Successfully updated user"})
}

func GetPlans(c fiber.Ctx) error {
	db := db.GetDB()

	var plans []models.Plan
	err := db.NewSelect().Model(&plans).Scan(context.Background())
	if err != nil {
		fmt.Println(err)
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	return c.Status(http.StatusOK).JSON(plans)
}

func CreateUser(c fiber.Ctx) error {
	signupData := new(models.SignupData)

	if err := c.Bind().JSON(signupData); err != nil {
		fmt.Println(err)
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	if signupData.Username == "" || signupData.Password == "" || signupData.Email == "" {
		return c.Status(http.StatusBadRequest).JSON(fiber.Map{"message": "A password, username and email are required!"})
	}

	// if email is not valid
	if !regexp.MustCompile(`^[a-z0-9._%+\-]+@[a-z0-9.\-]+\.[a-z]{2,4}$`).MatchString(signupData.Email) {
		return c.Status(http.StatusBadRequest).JSON(fiber.Map{"message": "A valid email is required!"})
	}

	db := db.GetDB()

	hash, err := bcrypt.GenerateFromPassword([]byte(signupData.Password), 12)
	if err != nil {
		fmt.Println(err)
		return c.Status(http.StatusInternalServerError).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	user := &models.User{
		Username:     signupData.Username,
		Email:        signupData.Email,
		PasswordHash: string(hash),
		PlanID:       1, // basic 10GB plan
	}
	_, err = db.NewInsert().Model(user).Exec(context.Background())

	if err != nil {
		return c.Status(http.StatusConflict).JSON(fiber.Map{"message": "A user with that email or username already exists!"})
	}

	err = db.NewSelect().Model(user).WherePK().Relation("Plan").Scan(context.Background())
	if err != nil {
		fmt.Println(err)
		return c.Status(http.StatusNotFound).JSON(fiber.Map{"message": "An unknown error occoured!"})
	}

	err = os.Mkdir(fmt.Sprintf("%s/%s", os.Getenv("STORAGE_PATH"), user.ID), os.ModePerm)
	if err != nil {
		fmt.Println(err)
		return err
	}

	return c.Status(http.StatusOK).JSON(fiber.Map{"message": "Successfully created user"})
}

// Stolen from Gitea https://github.com/go-gitea/gitea
func SystemStatus(c fiber.Ctx) error {
	updateSystemStatus()
	return c.Status(http.StatusOK).JSON(fiber.Map{
		"uptime":                     sysStatus.StartTime,
		"num_goroutine":              sysStatus.NumGoroutine,
		"cur_mem_usage":              sysStatus.MemAllocated,
		"total_mem_usage":            sysStatus.MemTotal,
		"mem_obtained":               sysStatus.MemSys,
		"ptr_lookup_times":           sysStatus.Lookups,
		"mem_allocations":            sysStatus.MemMallocs,
		"mem_frees":                  sysStatus.MemFrees,
		"cur_heap_usage":             sysStatus.HeapAlloc,
		"heap_mem_obtained":          sysStatus.HeapSys,
		"heap_mem_idle":              sysStatus.HeapIdle,
		"heap_mem_inuse":             sysStatus.HeapInuse,
		"heap_mem_release":           sysStatus.HeapReleased,
		"heap_objects":               sysStatus.HeapObjects,
		"bootstrap_stack_usage":      sysStatus.StackInuse,
		"stack_mem_obtained":         sysStatus.StackSys,
		"mspan_structures_usage":     sysStatus.MSpanInuse,
		"mspan_structures_obtained":  sysStatus.MSpanSys,
		"mcache_structures_usage":    sysStatus.MSpanInuse,
		"mcache_structures_obtained": sysStatus.MCacheSys,
		"buck_hash_sys":              sysStatus.BuckHashSys,
		"gc_sys":                     sysStatus.GCSys,
		"other_sys":                  sysStatus.OtherSys,
		"next_gc":                    sysStatus.NextGC,
		"last_gc_time":               sysStatus.LastGCTime,
		"pause_total_ns":             sysStatus.PauseTotalNs,
		"pause_ns":                   sysStatus.PauseNs,
		"num_gc":                     sysStatus.NumGC,
	})
}

var AppStartTime time.Time
var sysStatus struct {
	StartTime    string
	NumGoroutine int

	// General statistics.
	MemAllocated string // bytes allocated and still in use
	MemTotal     string // bytes allocated (even if freed)
	MemSys       string // bytes obtained from system (sum of XxxSys below)
	Lookups      uint64 // number of pointer lookups
	MemMallocs   uint64 // number of mallocs
	MemFrees     uint64 // number of frees

	// Main allocation heap statistics.
	HeapAlloc    string // bytes allocated and still in use
	HeapSys      string // bytes obtained from system
	HeapIdle     string // bytes in idle spans
	HeapInuse    string // bytes in non-idle span
	HeapReleased string // bytes released to the OS
	HeapObjects  uint64 // total number of allocated objects

	// Low-level fixed-size structure allocator statistics.
	//	Inuse is bytes used now.
	//	Sys is bytes obtained from system.
	StackInuse  string // bootstrap stacks
	StackSys    string
	MSpanInuse  string // mspan structures
	MSpanSys    string
	MCacheInuse string // mcache structures
	MCacheSys   string
	BuckHashSys string // profiling bucket hash table
	GCSys       string // GC metadata
	OtherSys    string // other system allocations

	// Garbage collector statistics.
	NextGC       string // next run in HeapAlloc time (bytes)
	LastGCTime   string // last run time
	PauseTotalNs string
	PauseNs      string // circular buffer of recent GC pause times, most recent at [(NumGC+255)%256]
	NumGC        uint32
}

func updateSystemStatus() {
	sysStatus.StartTime = AppStartTime.Format(time.RFC3339)

	m := new(runtime.MemStats)
	runtime.ReadMemStats(m)
	sysStatus.NumGoroutine = runtime.NumGoroutine()

	sysStatus.MemAllocated = FileSize(int64(m.Alloc))
	sysStatus.MemTotal = FileSize(int64(m.TotalAlloc))
	sysStatus.MemSys = FileSize(int64(m.Sys))
	sysStatus.Lookups = m.Lookups
	sysStatus.MemMallocs = m.Mallocs
	sysStatus.MemFrees = m.Frees

	sysStatus.HeapAlloc = FileSize(int64(m.HeapAlloc))
	sysStatus.HeapSys = FileSize(int64(m.HeapSys))
	sysStatus.HeapIdle = FileSize(int64(m.HeapIdle))
	sysStatus.HeapInuse = FileSize(int64(m.HeapInuse))
	sysStatus.HeapReleased = FileSize(int64(m.HeapReleased))
	sysStatus.HeapObjects = m.HeapObjects

	sysStatus.StackInuse = FileSize(int64(m.StackInuse))
	sysStatus.StackSys = FileSize(int64(m.StackSys))
	sysStatus.MSpanInuse = FileSize(int64(m.MSpanInuse))
	sysStatus.MSpanSys = FileSize(int64(m.MSpanSys))
	sysStatus.MCacheInuse = FileSize(int64(m.MCacheInuse))
	sysStatus.MCacheSys = FileSize(int64(m.MCacheSys))
	sysStatus.BuckHashSys = FileSize(int64(m.BuckHashSys))
	sysStatus.GCSys = FileSize(int64(m.GCSys))
	sysStatus.OtherSys = FileSize(int64(m.OtherSys))

	sysStatus.NextGC = FileSize(int64(m.NextGC))
	sysStatus.LastGCTime = time.Unix(0, int64(m.LastGC)).Format(time.RFC3339)
	sysStatus.PauseTotalNs = fmt.Sprintf("%.1fs", float64(m.PauseTotalNs)/1000/1000/1000)
	sysStatus.PauseNs = fmt.Sprintf("%.3fs", float64(m.PauseNs[(m.NumGC+255)%256])/1000/1000/1000)
	sysStatus.NumGC = m.NumGC
}

func FileSize(s int64) string {
	return humanize.IBytes(uint64(s))
}