package server

import (
	"fmt"
	"log/slog"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"

	"github.com/yyc12345/coconut-leaf/backend/config"
	"github.com/yyc12345/coconut-leaf/backend/database"
	"github.com/yyc12345/coconut-leaf/backend/utils"
)

// ResponseBody is the JSON envelope returned by every API endpoint, mirroring
// the legacy ConstructResponseBody: {success, error, data}.
type ResponseBody struct {
	Success bool   `json:"success"`
	Error   string `json:"error"`
	Data    any    `json:"data"`
}

// Handler holds the shared dependencies injected into every Gin handler: the
// database, the application logger and the loaded config.
type Handler struct {
	DB     database.Database
	Logger *slog.Logger
	Cfg    *config.Config
}

// region: Utilities

// respond wraps a (data, error) pair into a ResponseBody. The HTTP status is
// always 200; failures are encoded in the body, mirroring the legacy API.
func respond(c *gin.Context, data any, err error) {
	if err != nil {
		c.JSON(http.StatusOK, ResponseBody{Success: false, Error: err.Error()})
		return
	}
	c.JSON(http.StatusOK, ResponseBody{Success: true, Data: data})
}

// respondInvalidParam replies with the legacy "Invalid parameter" body.
func respondInvalidParam(c *gin.Context) {
	c.JSON(http.StatusOK, ResponseBody{Success: false, Error: "Invalid parameter"})
}

// fetchForm flattens the POST form into a map and logs it at debug level,
// mirroring the legacy SmartDbCaller "User Form" log.
func fetchForm(c *gin.Context, logger *slog.Logger) map[string]string {
	_ = c.Request.ParseForm()
	form := make(map[string]string, len(c.Request.PostForm))
	for k, v := range c.Request.PostForm {
		if len(v) > 0 {
			form[k] = v[0]
		}
	}
	logger.Debug("User Form", "form", form)
	return form
}

// fetchClientInfo returns the client user agent and IP, mirroring the legacy
// FetchClientNetworkInfo. The real IP (X-Forwarded-For behind Nginx) comes from
// gin's c.ClientIP().
func fetchClientInfo(c *gin.Context) (ua, ip string) {
	ua = c.Request.UserAgent()
	ip = c.ClientIP()
	if ip == "" {
		ip = "0.0.0.0"
	}
	return ua, ip
}

// endregion

// Run sets up the Gin engine with all routes bound to the handler and starts
// listening on the configured web port.
func Run(handler *Handler) error {
	r := gin.Default()
	registerRoutes(r, handler)
	return r.Run(fmt.Sprintf(":%d", handler.Cfg.Web.Port))
}

func registerRoutes(r *gin.Engine, h *Handler) {
	// common
	r.POST("/common/salt", h.CommonSalt)
	r.POST("/common/login", h.CommonLogin)
	r.POST("/common/webLogin", h.CommonWebLogin)
	r.POST("/common/logout", h.CommonLogout)
	r.POST("/common/tokenValid", h.CommonTokenValid)

	// calendar
	r.POST("/calendar/getFull", h.CalendarGetFull)
	r.POST("/calendar/getList", h.CalendarGetList)
	r.POST("/calendar/getDetail", h.CalendarGetDetail)
	r.POST("/calendar/update", h.CalendarUpdate)
	r.POST("/calendar/add", h.CalendarAdd)
	r.POST("/calendar/delete", h.CalendarDelete)

	// collection
	r.POST("/collection/getFullOwn", h.CollectionGetFullOwn)
	r.POST("/collection/getListOwn", h.CollectionGetListOwn)
	r.POST("/collection/getDetailOwn", h.CollectionGetDetailOwn)
	r.POST("/collection/addOwn", h.CollectionAddOwn)
	r.POST("/collection/updateOwn", h.CollectionUpdateOwn)
	r.POST("/collection/deleteOwn", h.CollectionDeleteOwn)
	r.POST("/collection/getSharing", h.CollectionGetSharing)
	r.POST("/collection/deleteSharing", h.CollectionDeleteSharing)
	r.POST("/collection/addSharing", h.CollectionAddSharing)
	r.POST("/collection/getShared", h.CollectionGetShared)

	// todo
	r.POST("/todo/getFull", h.TodoGetFull)
	r.POST("/todo/getList", h.TodoGetList)
	r.POST("/todo/getDetail", h.TodoGetDetail)
	r.POST("/todo/add", h.TodoAdd)
	r.POST("/todo/update", h.TodoUpdate)
	r.POST("/todo/delete", h.TodoDelete)

	// admin
	r.POST("/admin/get", h.AdminGet)
	r.POST("/admin/add", h.AdminAdd)
	r.POST("/admin/update", h.AdminUpdate)
	r.POST("/admin/delete", h.AdminDelete)

	// profile
	r.POST("/profile/isAdmin", h.ProfileIsAdmin)
	r.POST("/profile/changePassword", h.ProfileChangePassword)
	r.POST("/profile/getToken", h.ProfileGetToken)
	r.POST("/profile/deleteToken", h.ProfileDeleteToken)
}

// region: API Route

// region: Common

func (h *Handler) CommonSalt(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	username, ok := form["username"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CommonSalt(c.Request.Context(), username)
	respond(c, data, err)
}

func (h *Handler) CommonLogin(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	username, okU := form["username"]
	password, okP := form["password"]
	if !okU || !okP {
		respondInvalidParam(c)
		return
	}
	clientUa, clientIp := fetchClientInfo(c)
	data, err := h.DB.CommonLogin(c.Request.Context(), username, password, clientUa, clientIp)
	respond(c, data, err)
}

func (h *Handler) CommonWebLogin(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	username, okU := form["username"]
	password, okP := form["password"]
	if !okU || !okP {
		respondInvalidParam(c)
		return
	}
	clientUa, clientIp := fetchClientInfo(c)
	data, err := h.DB.CommonWebLogin(c.Request.Context(), username, password, clientUa, clientIp)
	respond(c, data, err)
}

func (h *Handler) CommonLogout(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CommonLogout(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) CommonTokenValid(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CommonTokenValid(c.Request.Context(), token)
	respond(c, data, err)
}

// endregion

// region: Calendar

func (h *Handler) CalendarGetFull(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	sds, okS := form["startDateTime"]
	eds, okE := form["endDateTime"]
	if !okT || !okS || !okE {
		respondInvalidParam(c)
		return
	}
	startDateTime, err1 := strconv.ParseInt(sds, 10, 64)
	endDateTime, err2 := strconv.ParseInt(eds, 10, 64)
	if err1 != nil || err2 != nil {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CalendarGetFull(c.Request.Context(), token, startDateTime, endDateTime)
	respond(c, data, err)
}

func (h *Handler) CalendarGetList(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	sds, okS := form["startDateTime"]
	eds, okE := form["endDateTime"]
	if !okT || !okS || !okE {
		respondInvalidParam(c)
		return
	}
	startDateTime, err1 := strconv.ParseInt(sds, 10, 64)
	endDateTime, err2 := strconv.ParseInt(eds, 10, 64)
	if err1 != nil || err2 != nil {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CalendarGetList(c.Request.Context(), token, startDateTime, endDateTime)
	respond(c, data, err)
}

func (h *Handler) CalendarGetDetail(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	if !okT || !okU {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CalendarGetDetail(c.Request.Context(), token, uuid)
	respond(c, data, err)
}

func (h *Handler) CalendarUpdate(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okL {
		respondInvalidParam(c)
		return
	}

	var opts database.CalendarUpdateOptions
	provided := 0
	if v, ok := form["belongTo"]; ok {
		opts.BelongTo = &v
		provided++
	}
	if v, ok := form["title"]; ok {
		opts.Title = &v
		provided++
	}
	if v, ok := form["description"]; ok {
		opts.Description = &v
		provided++
	}
	if v, ok := form["eventDateTimeStart"]; ok {
		n, err := strconv.ParseInt(v, 10, 64)
		if err != nil {
			respondInvalidParam(c)
			return
		}
		opts.EventDateTimeStart = &n
		provided++
	}
	if v, ok := form["eventDateTimeEnd"]; ok {
		n, err := strconv.ParseInt(v, 10, 64)
		if err != nil {
			respondInvalidParam(c)
			return
		}
		opts.EventDateTimeEnd = &n
		provided++
	}
	if v, ok := form["loopRules"]; ok {
		opts.LoopRules = &v
		provided++
	}
	if v, ok := form["timezoneOffset"]; ok {
		n, err := strconv.ParseInt(v, 10, 64)
		if err != nil {
			respondInvalidParam(c)
			return
		}
		opts.TimezoneOffset = &n
		provided++
	}
	if provided == 0 {
		respondInvalidParam(c)
		return
	}

	data, err := h.DB.CalendarUpdate(c.Request.Context(), token, uuid, lastChange, opts)
	respond(c, data, err)
}

func (h *Handler) CalendarAdd(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	belongTo, okB := form["belongTo"]
	title, okTi := form["title"]
	description, okD := form["description"]
	loopRules, okL := form["loopRules"]
	edtsStr, okES := form["eventDateTimeStart"]
	edteStr, okEE := form["eventDateTimeEnd"]
	tzoStr, okTZ := form["timezoneOffset"]
	if !okT || !okB || !okTi || !okD || !okL || !okES || !okEE || !okTZ {
		respondInvalidParam(c)
		return
	}
	edts, err1 := strconv.ParseInt(edtsStr, 10, 64)
	edte, err2 := strconv.ParseInt(edteStr, 10, 64)
	tzo, err3 := strconv.ParseInt(tzoStr, 10, 64)
	if err1 != nil || err2 != nil || err3 != nil {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CalendarAdd(c.Request.Context(), token, belongTo, title, description, edts, edte, loopRules, tzo)
	respond(c, data, err)
}

func (h *Handler) CalendarDelete(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okL {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CalendarDelete(c.Request.Context(), token, uuid, lastChange)
	respond(c, data, err)
}

// endregion

// region: Collection

func (h *Handler) CollectionGetFullOwn(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionGetFullOwn(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) CollectionGetListOwn(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionGetListOwn(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) CollectionGetDetailOwn(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	if !okT || !okU {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionGetDetailOwn(c.Request.Context(), token, uuid)
	respond(c, data, err)
}

func (h *Handler) CollectionAddOwn(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	name, okN := form["name"]
	if !okT || !okN {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionAddOwn(c.Request.Context(), token, name)
	respond(c, data, err)
}

func (h *Handler) CollectionUpdateOwn(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	name, okN := form["name"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okN || !okL {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionUpdateOwn(c.Request.Context(), token, uuid, name, lastChange)
	respond(c, data, err)
}

func (h *Handler) CollectionDeleteOwn(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okL {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionDeleteOwn(c.Request.Context(), token, uuid, lastChange)
	respond(c, data, err)
}

func (h *Handler) CollectionGetSharing(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	if !okT || !okU {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionGetSharing(c.Request.Context(), token, uuid)
	respond(c, data, err)
}

func (h *Handler) CollectionDeleteSharing(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	target, okG := form["target"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okG || !okL {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionDeleteSharing(c.Request.Context(), token, uuid, target, lastChange)
	respond(c, data, err)
}

func (h *Handler) CollectionAddSharing(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	target, okG := form["target"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okG || !okL {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionAddSharing(c.Request.Context(), token, uuid, target, lastChange)
	respond(c, data, err)
}

func (h *Handler) CollectionGetShared(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.CollectionGetShared(c.Request.Context(), token)
	respond(c, data, err)
}

// endregion

// region: Todo

func (h *Handler) TodoGetFull(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.TodoGetFull(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) TodoGetList(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.TodoGetList(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) TodoGetDetail(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	if !okT || !okU {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.TodoGetDetail(c.Request.Context(), token, uuid)
	respond(c, data, err)
}

func (h *Handler) TodoAdd(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.TodoAdd(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) TodoUpdate(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	dataField, okD := form["data"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okD || !okL {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.TodoUpdate(c.Request.Context(), token, uuid, dataField, lastChange)
	respond(c, data, err)
}

func (h *Handler) TodoDelete(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	uuid, okU := form["uuid"]
	lastChange, okL := form["lastChange"]
	if !okT || !okU || !okL {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.TodoDelete(c.Request.Context(), token, uuid, lastChange)
	respond(c, data, err)
}

// endregion

// region: Admin

func (h *Handler) AdminGet(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.AdminGet(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) AdminAdd(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	username, okU := form["username"]
	if !okT || !okU {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.AdminAdd(c.Request.Context(), token, username)
	respond(c, data, err)
}

func (h *Handler) AdminUpdate(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	username, okU := form["username"]
	if !okT || !okU {
		respondInvalidParam(c)
		return
	}

	var opts database.AdminUpdateOptions
	provided := 0
	if v, ok := form["password"]; ok {
		opts.Password = &v
		provided++
	}
	if v, ok := form["isAdmin"]; ok {
		b := utils.Str2Bool(v)
		opts.IsAdmin = &b
		provided++
	}
	if provided == 0 {
		respondInvalidParam(c)
		return
	}

	data, err := h.DB.AdminUpdate(c.Request.Context(), token, username, opts)
	respond(c, data, err)
}

func (h *Handler) AdminDelete(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	username, okU := form["username"]
	if !okT || !okU {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.AdminDelete(c.Request.Context(), token, username)
	respond(c, data, err)
}

// endregion

// region: Profile

func (h *Handler) ProfileIsAdmin(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.ProfileIsAdmin(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) ProfileChangePassword(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	password, okP := form["password"]
	if !okT || !okP {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.ProfileChangePassword(c.Request.Context(), token, password)
	respond(c, data, err)
}

func (h *Handler) ProfileGetToken(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, ok := form["token"]
	if !ok {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.ProfileGetToken(c.Request.Context(), token)
	respond(c, data, err)
}

func (h *Handler) ProfileDeleteToken(c *gin.Context) {
	form := fetchForm(c, h.Logger)
	token, okT := form["token"]
	deleteToken, okD := form["deleteToken"]
	if !okT || !okD {
		respondInvalidParam(c)
		return
	}
	data, err := h.DB.ProfileDeleteToken(c.Request.Context(), token, deleteToken)
	respond(c, data, err)
}

// endregion

// endregion