package pkg

import (
	"context"
	"errors"
	"html/template"
	"net/http"
	"net/url"
	"strconv"
	"strings"
)

const (
	ContextCompanyKey = "numerus-company"
)

type Company struct {
	Id   int
	Slug string
}

func CompanyHandler(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		slug := r.URL.Path
		if idx := strings.IndexByte(slug, '/'); idx >= 0 {
			slug = slug[:idx]
		}

		conn := getConn(r)
		company := &Company{
			Slug: slug,
		}
		err := conn.QueryRow(r.Context(), "select company_id from company where slug = $1", slug).Scan(&company.Id)
		if err != nil {
			http.NotFound(w, r)
			return
		}
		ctx := context.WithValue(r.Context(), ContextCompanyKey, company)
		r = r.WithContext(ctx)

		// Same as StripPrefix
		p := strings.TrimPrefix(r.URL.Path, slug)
		rp := strings.TrimPrefix(r.URL.RawPath, slug)
		if len(p) < len(r.URL.Path) && (r.URL.RawPath == "" || len(rp) < len(r.URL.RawPath)) {
			r2 := new(http.Request)
			*r2 = *r
			r2.URL = new(url.URL)
			*r2.URL = *r.URL
			if p == "" {
				r2.URL.Path = "/"
			} else {
				r2.URL.Path = p
			}
			r2.URL.RawPath = rp
			next.ServeHTTP(w, r2)
		} else {
			http.NotFound(w, r)
		}
	})
}

func getCompany(r *http.Request) *Company {
	company := r.Context().Value(ContextCompanyKey)
	if company == nil {
		return nil
	}
	return company.(*Company)
}

type CurrencyOption struct {
	Code   string
	Symbol string
}

type CountryOption struct {
	Code string
	Name string
}

type Tax struct {
	Id   int
	Name string
	Rate int
}

type taxDetailsForm struct {
	*contactForm
	Currency *SelectField
}

func newTaxDetailsForm(ctx context.Context, conn *Conn, locale *Locale) *taxDetailsForm {
	return &taxDetailsForm{
		contactForm: newContactForm(ctx, conn, locale),
		Currency: &SelectField{
			Name:     "currency",
			Label:    pgettext("input", "Currency", locale),
			Options:  MustGetOptions(ctx, conn, "select currency_code, currency_symbol from currency order by currency_code"),
			Selected: "EUR",
		},
	}
}

func (form *taxDetailsForm) Parse(r *http.Request) error {
	if err := form.contactForm.Parse(r); err != nil {
		return err
	}
	form.Currency.FillValue(r)
	return nil
}

func (form *taxDetailsForm) Validate(ctx context.Context, conn *Conn) bool {
	validator := newFormValidator()
	validator.CheckValidSelectOption(form.Currency, gettext("Selected currency is not valid.", form.locale))
	return form.contactForm.Validate(ctx, conn) && validator.AllOK()
}

func (form *taxDetailsForm) mustFillFromDatabase(ctx context.Context, conn *Conn, company *Company) *taxDetailsForm {
	err := conn.QueryRow(ctx, "select business_name, substr(vatin::text, 3), trade_name, phone, email, web, address, city, province, postal_code, country_code, currency_code from company where company_id = $1", company.Id).Scan(form.BusinessName, form.VATIN, form.TradeName, form.Phone, form.Email, form.Web, form.Address, form.City, form.Province, form.PostalCode, form.Country, form.Currency)
	if err != nil {
		panic(err)
	}
	return form
}

type TaxDetailsPage struct {
	DetailsForm *taxDetailsForm
	NewTaxForm  *newTaxForm
	Taxes       []*Tax
}

func CompanyTaxDetailsHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		locale := getLocale(r)
		conn := getConn(r)
		page := &TaxDetailsPage{
			DetailsForm: newTaxDetailsForm(r.Context(), conn, locale),
			NewTaxForm:  newNewTaxForm(locale),
		}
		company := mustGetCompany(r)
		if r.Method == "POST" {
			if err := page.DetailsForm.Parse(r); err != nil {
				http.Error(w, err.Error(), http.StatusBadRequest)
				return
			}
			if err := verifyCsrfTokenValid(r); err != nil {
				http.Error(w, err.Error(), http.StatusForbidden)
				return
			}
			if ok := page.DetailsForm.Validate(r.Context(), conn); ok {
				form := page.DetailsForm
				conn.MustExec(r.Context(), "update company set business_name = $1, vatin = ($11 || $2)::vatin, trade_name = $3, phone = parse_packed_phone_number($4, $11), email = $5, web = $6, address = $7, city = $8, province = $9, postal_code = $10, country_code = $11, currency_code = $12 where company_id = $13", form.BusinessName, form.VATIN, form.TradeName, form.Phone, form.Email, form.Web, form.Address, form.City, form.Province, form.PostalCode, form.Country, form.Currency, company.Id)
				http.Redirect(w, r, "/company/"+company.Slug+"/tax-details", http.StatusSeeOther)
				return
			}
			w.WriteHeader(http.StatusUnprocessableEntity)
		} else {
			page.DetailsForm.mustFillFromDatabase(r.Context(), conn, company)
		}
		page.Taxes = mustGetTaxes(r.Context(), conn, company)
		mustRenderAppTemplate(w, r, "tax-details.gohtml", page)
	})
}

func mustGetCompany(r *http.Request) *Company {
	company := getCompany(r)
	if company == nil {
		panic(errors.New("company: required but not found"))
	}
	return company
}

func mustGetTaxes(ctx context.Context, conn *Conn, company *Company) []*Tax {
	rows, err := conn.Query(ctx, "select tax_id, name, (rate * 100)::integer from tax where company_id = $1 order by rate, name", company.Id)
	if err != nil {
		panic(err)
	}
	defer rows.Close()

	var taxes []*Tax
	for rows.Next() {
		tax := &Tax{}
		err = rows.Scan(&tax.Id, &tax.Name, &tax.Rate)
		if err != nil {
			panic(err)
		}
		taxes = append(taxes, tax)
	}
	if rows.Err() != nil {
		panic(rows.Err())
	}

	return taxes
}

type newTaxForm struct {
	locale *Locale
	Name   *InputField
	Rate   *InputField
}

func newNewTaxForm(locale *Locale) *newTaxForm {
	return &newTaxForm{
		locale: locale,
		Name: &InputField{
			Name:     "tax_name",
			Label:    pgettext("input", "Tax name", locale),
			Type:     "text",
			Required: true,
		},
		Rate: &InputField{
			Name:     "tax_rate",
			Label:    pgettext("input", "Rate (%)", locale),
			Type:     "number",
			Required: true,
			Attributes: []template.HTMLAttr{
				"min=-99",
				"max=99",
			},
		},
	}
}

func (form *newTaxForm) Parse(r *http.Request) error {
	if err := r.ParseForm(); err != nil {
		return err
	}
	form.Name.FillValue(r)
	form.Rate.FillValue(r)
	return nil
}

func (form *newTaxForm) Validate() bool {
	validator := newFormValidator()
	validator.CheckRequiredInput(form.Name, gettext("Tax name can not be empty.", form.locale))
	if validator.CheckRequiredInput(form.Rate, gettext("Tax rate can not be empty.", form.locale)) {
		validator.CheckValidInteger(form.Rate, -99, 99, gettext("Tax rate must be an integer between -99 and 99.", form.locale))
	}
	return validator.AllOK()
}

func CompanyTaxHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		param := r.URL.Path
		if idx := strings.LastIndexByte(param, '/'); idx >= 0 {
			param = param[idx+1:]
		}
		conn := getConn(r)
		company := mustGetCompany(r)
		if taxId, err := strconv.Atoi(param); err == nil {
			if err := verifyCsrfTokenValid(r); err != nil {
				http.Error(w, err.Error(), http.StatusForbidden)
				return
			}
			conn.MustExec(r.Context(), "delete from tax where tax_id = $1", taxId)
			http.Redirect(w, r, "/company/"+company.Slug+"/tax-details", http.StatusSeeOther)
		} else {
			locale := getLocale(r)
			form := newNewTaxForm(locale)
			if err := form.Parse(r); err != nil {
				http.Error(w, err.Error(), http.StatusBadRequest)
				return
			}
			if err := verifyCsrfTokenValid(r); err != nil {
				http.Error(w, err.Error(), http.StatusForbidden)
				return
			}
			if form.Validate() {
				conn.MustExec(r.Context(), "insert into tax (company_id, name, rate) values ($1, $2, $3 / 100::decimal)", company.Id, form.Name, form.Rate.Integer())
				http.Redirect(w, r, "/company/"+company.Slug+"/tax-details", http.StatusSeeOther)
			} else {
				w.WriteHeader(http.StatusUnprocessableEntity)
			}
			page := &TaxDetailsPage{
				DetailsForm: newTaxDetailsForm(r.Context(), conn, locale).mustFillFromDatabase(r.Context(), conn, company),
				NewTaxForm:  form,
				Taxes:       mustGetTaxes(r.Context(), conn, company),
			}
			mustRenderAppTemplate(w, r, "tax-details.gohtml", page)
		}
	})
}