package main

import (
	"bytes"
	"net/http"
	"strconv"
	"time"

	"brainminder.speedtech.it/internal/password"
	"brainminder.speedtech.it/internal/request"
	"brainminder.speedtech.it/internal/response"
	"brainminder.speedtech.it/internal/token"
	"brainminder.speedtech.it/internal/validator"
	"brainminder.speedtech.it/models"

	"github.com/alexedwards/flow"
)

func (app *application) home(w http.ResponseWriter, r *http.Request) {
	session, _ := app.sessionStore.Get(r, "session")
	current_notebook_id := session.Values["current_notebook_id"]
	params := r.URL.Query()

	if r.Method == http.MethodPost {
		err := r.ParseForm()
		if err != nil {
			app.serverError(w, r, err)
			return
		}
		current_notebook_id = r.PostForm.Get("current_notebook_id")
		session.Values["current_notebook_id"] = current_notebook_id
		session.Save(r, w)
	}

	var fullBuf = new(bytes.Buffer)

	data := app.newTemplateData(r)
	itemModel := models.NewItemModel(app.db)

	var notebook_id int64 = -1
	if current_notebook_id != nil {
		notebook_id, _ = strconv.ParseInt(current_notebook_id.(string), 10, 64)
	}

	criteria := map[string]any{
		"On_dashboard": 1,
		"notebook_id":  notebook_id,
	}

	offset_str := r.URL.Query().Get("offset")
	if len(offset_str) == 0 {
		offset_str = "0"
	}
	offset, _ := strconv.ParseInt(offset_str, 10, 64)

	items, _, _ := itemModel.Find(criteria, offset)
	data["items"] = items
	data["offset"] = offset

	if r.Header.Get("HX-Request") == "true" {
		out := params.Get("out")

		if out == "items" {
			err := response.HXFragment(fullBuf, []string{"pages/home_items.tmpl"}, "home:items", data)
			if err != nil {
				app.serverError(w, r, err)
			}
		} else {
			err := response.HXFragment(fullBuf, []string{"pages/home.tmpl", "pages/home_items.tmpl"}, "page:content", data)
			if err != nil {
				app.serverError(w, r, err)
			}

			err = response.HXFragmentOOB(fullBuf, []string{"pages/home_title.tmpl"}, "page:title", data, "page-title")
			if err != nil {
				app.serverError(w, r, err)
			}
		}
		fullBuf.WriteTo(w)
	} else {
		err := response.Page(w, http.StatusOK, data, []string{"pages/home.tmpl", "pages/home_items.tmpl", "pages/home_title.tmpl"})
		if err != nil {
			app.serverError(w, r, err)
		}
	}
}

func (app *application) signup(w http.ResponseWriter, r *http.Request) {
	var form struct {
		Email     string              `form:"Email"`
		Password  string              `form:"Password"`
		Validator validator.Validator `form:"-"`
	}

	switch r.Method {
	case http.MethodGet:
		data := app.newTemplateData(r)
		data["Form"] = form

		err := response.Page(w, http.StatusOK, data, []string{"pages/signup.tmpl"})
		if err != nil {
			app.serverError(w, r, err)
		}

	case http.MethodPost:
		err := request.DecodePostForm(r, &form)
		if err != nil {
			app.badRequest(w, err)
			return
		}

		_, found, err := app.db.GetUserByEmail(form.Email)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		form.Validator.CheckField(form.Email != "", "Email", "Email is required")
		form.Validator.CheckField(validator.Matches(form.Email, validator.RgxEmail), "Email", "Must be a valid email address")
		form.Validator.CheckField(!found, "Email", "Email is already in use")

		form.Validator.CheckField(form.Password != "", "Password", "Password is required")
		form.Validator.CheckField(len(form.Password) >= 8, "Password", "Password is too short")
		form.Validator.CheckField(len(form.Password) <= 72, "Password", "Password is too long")
		form.Validator.CheckField(validator.NotIn(form.Password, password.CommonPasswords...), "Password", "Password is too common")

		if form.Validator.HasErrors() {
			data := app.newTemplateData(r)
			data["Form"] = form

			err := response.Page(w, http.StatusUnprocessableEntity, data, []string{"pages/signup.tmpl"}, "full")
			if err != nil {
				app.serverError(w, r, err)
			}
			return
		}

		hashedPassword, err := password.Hash(form.Password)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		id, err := app.db.InsertUser(form.Email, hashedPassword)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		session, err := app.sessionStore.Get(r, "session")
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		session.Values["userID"] = id

		err = session.Save(r, w)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		http.Redirect(w, r, "/", http.StatusSeeOther)
	}
}

func (app *application) login(w http.ResponseWriter, r *http.Request) {
	var form struct {
		Email     string              `form:"Email"`
		Password  string              `form:"Password"`
		Validator validator.Validator `form:"-"`
	}

	switch r.Method {
	case http.MethodGet:
		data := app.newTemplateData(r)
		data["Form"] = form

		err := response.Page(w, http.StatusOK, data, []string{"pages/login.tmpl"}, "full")
		if err != nil {
			app.serverError(w, r, err)
		}

	case http.MethodPost:
		err := request.DecodePostForm(r, &form)
		if err != nil {
			app.badRequest(w, err)
			return
		}

		user, found, err := app.db.GetUserByEmail(form.Email)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		form.Validator.CheckField(form.Email != "", "Email", "Email is required")
		form.Validator.CheckField(found, "Email", "Email address could not be found")

		if found {
			passwordMatches, err := password.Matches(form.Password, user.HashedPassword)
			if err != nil {
				app.serverError(w, r, err)
				return
			}

			form.Validator.CheckField(form.Password != "", "Password", "Password is required")
			form.Validator.CheckField(passwordMatches, "Password", "Password is incorrect")
		}

		if form.Validator.HasErrors() {
			data := app.newTemplateData(r)
			data["Form"] = form

			err := response.Page(w, http.StatusUnprocessableEntity, data, []string{"pages/login.tmpl"}, "full")
			if err != nil {
				app.serverError(w, r, err)
			}
			return
		}

		session, err := app.sessionStore.Get(r, "session")
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		session.Values["userID"] = user.ID

		redirectPath, ok := session.Values["redirectPathAfterLogin"].(string)
		if ok {
			delete(session.Values, "redirectPathAfterLogin")
		} else {
			redirectPath = "/"
		}

		err = session.Save(r, w)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		http.Redirect(w, r, redirectPath, http.StatusSeeOther)
	}
}

func (app *application) logout(w http.ResponseWriter, r *http.Request) {
	session, err := app.sessionStore.Get(r, "session")
	if err != nil {
		app.serverError(w, r, err)
		return
	}

	delete(session.Values, "userID")

	err = session.Save(r, w)
	if err != nil {
		app.serverError(w, r, err)
		return
	}

	http.Redirect(w, r, "/login", http.StatusSeeOther)
}

func (app *application) forgottenPassword(w http.ResponseWriter, r *http.Request) {
	var form struct {
		Email     string              `form:"Email"`
		Validator validator.Validator `form:"-"`
	}

	switch r.Method {
	case http.MethodGet:
		data := app.newTemplateData(r)
		data["Form"] = form

		err := response.Page(w, http.StatusOK, data, []string{"pages/forgotten-password.tmpl"}, "full")
		if err != nil {
			app.serverError(w, r, err)
		}

	case http.MethodPost:
		err := request.DecodePostForm(r, &form)
		if err != nil {
			app.badRequest(w, err)
			return
		}

		user, found, err := app.db.GetUserByEmail(form.Email)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		form.Validator.CheckField(form.Email != "", "Email", "Email is required")
		form.Validator.CheckField(validator.Matches(form.Email, validator.RgxEmail), "Email", "Must be a valid email address")
		form.Validator.CheckField(found, "Email", "No matching email found")

		if form.Validator.HasErrors() {
			data := app.newTemplateData(r)
			data["Form"] = form

			err := response.Page(w, http.StatusUnprocessableEntity, data, []string{"pages/forgotten-password.tmpl"}, "full")
			if err != nil {
				app.serverError(w, r, err)
			}
			return
		}

		plaintextToken, err := token.New()
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		hashedToken := token.Hash(plaintextToken)

		err = app.db.InsertPasswordReset(hashedToken, user.ID, 24*time.Hour)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		data := app.newEmailData()
		data["PlaintextToken"] = plaintextToken

		err = app.mailer.Send(user.Email, data, "forgotten-password.tmpl")
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		http.Redirect(w, r, "/forgotten-password-confirmation", http.StatusSeeOther)
	}
}

func (app *application) forgottenPasswordConfirmation(w http.ResponseWriter, r *http.Request) {
	data := app.newTemplateData(r)

	err := response.Page(w, http.StatusOK, data, []string{"pages/forgotten-password-confirmation.tmpl"}, "full")
	if err != nil {
		app.serverError(w, r, err)
	}
}

func (app *application) passwordReset(w http.ResponseWriter, r *http.Request) {
	plaintextToken := flow.Param(r.Context(), "plaintextToken")

	hashedToken := token.Hash(plaintextToken)

	passwordReset, found, err := app.db.GetPasswordReset(hashedToken)
	if err != nil {
		app.serverError(w, r, err)
		return
	}

	if !found {
		data := app.newTemplateData(r)
		data["InvalidLink"] = true

		err := response.Page(w, http.StatusUnprocessableEntity, data, []string{"pages/password-reset.tmpl"}, "full")
		if err != nil {
			app.serverError(w, r, err)
		}
		return
	}

	var form struct {
		NewPassword string              `form:"NewPassword"`
		Validator   validator.Validator `form:"-"`
	}

	switch r.Method {
	case http.MethodGet:
		data := app.newTemplateData(r)
		data["Form"] = form
		data["PlaintextToken"] = plaintextToken

		err := response.Page(w, http.StatusOK, data, []string{"pages/password-reset.tmpl"})
		if err != nil {
			app.serverError(w, r, err)
		}

	case http.MethodPost:
		err := request.DecodePostForm(r, &form)
		if err != nil {
			app.badRequest(w, err)
			return
		}

		form.Validator.CheckField(form.NewPassword != "", "NewPassword", "New password is required")
		form.Validator.CheckField(len(form.NewPassword) >= 8, "NewPassword", "New password is too short")
		form.Validator.CheckField(len(form.NewPassword) <= 72, "NewPassword", "New password is too long")
		form.Validator.CheckField(validator.NotIn(form.NewPassword, password.CommonPasswords...), "NewPassword", "New password is too common")

		if form.Validator.HasErrors() {
			data := app.newTemplateData(r)
			data["Form"] = form
			data["PlaintextToken"] = plaintextToken

			err := response.Page(w, http.StatusUnprocessableEntity, data, []string{"pages/password-reset.tmpl"}, "full")
			if err != nil {
				app.serverError(w, r, err)
			}
			return
		}

		hashedPassword, err := password.Hash(form.NewPassword)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		err = app.db.UpdateUserHashedPassword(passwordReset.UserID, hashedPassword)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		err = app.db.DeletePasswordResets(passwordReset.UserID)
		if err != nil {
			app.serverError(w, r, err)
			return
		}

		http.Redirect(w, r, "/password-reset-confirmation", http.StatusSeeOther)
	}
}

func (app *application) passwordResetConfirmation(w http.ResponseWriter, r *http.Request) {
	data := app.newTemplateData(r)

	err := response.Page(w, http.StatusOK, data, []string{"pages/password-reset-confirmation.tmpl"}, "full")
	if err != nil {
		app.serverError(w, r, err)
	}
}