package main

import (
	"bytes"
	"database/sql"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"strconv"
	"strings"

	"git.tilde.town/tildetown/town/codes"
	"git.tilde.town/tildetown/town/sshkey"
	"github.com/charmbracelet/lipgloss"
	_ "github.com/mattn/go-sqlite3"
	"github.com/mattn/go-tty"
)

// TODO consider local-only help command for renaming, email mgmt, deleting account

// TODO put colorscheme, prompting stuff into own packages for use in the other commands. would be good to get off of survey.

func connectDB() (*sql.DB, error) {
	db, err := sql.Open("sqlite3", "/town/var/codes/codes.db?mode=rw")
	if err != nil {
		return nil, err
	}

	return db, nil
}

type colorScheme struct {
	Header   func(string) string
	Subtitle func(string) string
	Prompt   func(string) string
	Email    func(string) string
	Option   func(string) string
	Error    func(string) string
}

func newColorScheme() colorScheme {
	s2r := func(s lipgloss.Style) func(string) string {
		return s.Render
	}
	c := func(s string) lipgloss.Color {
		return lipgloss.Color(s)
	}
	s := lipgloss.NewStyle
	return colorScheme{
		Header:   s2r(s().Bold(true).Foreground(c("#E0B0FF"))),
		Subtitle: s2r(s().Italic(true).Foreground(c("gray"))),
		Email:    s2r(s().Bold(true).Underline(true)),
		Prompt:   s2r(s().Bold(true).Foreground(c("#00752d"))),
		Option:   s2r(s().Bold(true).Foreground(c("#38747a"))),
		Error:    s2r(s().Bold(true).Foreground(c("#f43124"))),
	}
}

type Prompter struct {
	cs  colorScheme
	tty *tty.TTY
}

func NewPrompter(tty *tty.TTY, cs colorScheme) *Prompter {
	return &Prompter{
		cs:  cs,
		tty: tty,
	}
}

func (p *Prompter) String(prompt string) (string, error) {
	fmt.Println("")
	fmt.Println(p.cs.Prompt(prompt))
	fmt.Println(p.cs.Subtitle("(type your answer below and press enter to submit)"))
	s, err := p.tty.ReadString()
	if err != nil {
		return "", fmt.Errorf("couldn't collect input: %w", err)
	}

	return s, nil
}

func (p *Prompter) Select(prompt string, opts []string) (int, error) {
	fmt.Println()
	fmt.Println(p.cs.Prompt(prompt))
	fmt.Println(p.cs.Subtitle("(pick an option using the corresponding number)"))

	chosen := -1
	for chosen < 0 {
		fmt.Println()
		for ix, o := range opts {
			fmt.Printf("%s: %s\n", p.cs.Option(fmt.Sprintf("%d", ix+1)), o)
		}
		r, err := p.tty.ReadRune()
		if err != nil {
			return -1, fmt.Errorf("could not collect answer for '%s': %w", prompt, err)
		}
		c, err := strconv.Atoi(string(r))
		if err != nil {
			fmt.Println()
			fmt.Printf("I could not understand '%s'. Try again, please.\n", string(r))
			continue
		}
		if c > len(opts) || c == 0 {
			fmt.Println()
			fmt.Printf("%s is not an option. Try again, please.\n", string(r))
			continue
		}
		chosen = c - 1
	}

	fmt.Println("")

	return chosen, nil
}

func _main(cs colorScheme) error {
	db, err := connectDB()
	if err != nil {
		return fmt.Errorf("could not connect to database. please let root@tilde.town know about this.")
	}

	fmt.Println(cs.Header("Hi, you have reached the tilde town help desk."))
	fmt.Println()
	fmt.Println("Please check out the options below.")
	fmt.Printf("If none of them apply to your case, you can email %s. \n", cs.Email("root@tilde.town"))
	tty, err := tty.Open()
	if err != nil {
		return fmt.Errorf("could not open tty: %w", err)
	}
	defer tty.Close()

	p := NewPrompter(tty, cs)

	options := []string{
		"I need to request that a new SSH key be added to my account.",
		"I have a code from my e-mail to redeem for a new SSH key",
		"I just want out of here",
	}
	c, err := p.Select("What do you need help with?", options)

	defer func() {
		fmt.Println()
		fmt.Println(cs.Header("bye~"))
	}()

	switch c {
	case 0:
		return collectEmail(db, cs, p)
	case 1:
		return redeemCode(db, cs, p)
	case 2:
		return nil
	}

	return nil
}

func emailToUsername(email string) (string, error) {
	cmd := exec.Command("sudo", "/town/bin/emailtouser", email)
	stderrBuff := bytes.NewBuffer([]byte{})
	stdoutBuff := bytes.NewBuffer([]byte{})
	cmd.Stderr = stderrBuff
	cmd.Stdout = stdoutBuff
	if err := cmd.Run(); err != nil {
		return "", fmt.Errorf("emailtouser failed with '%s': %w", stderrBuff.String(), err)
	}

	return stdoutBuff.String(), nil
}

func collectEmail(db *sql.DB, cs colorScheme, p *Prompter) error {
	fmt.Println(cs.Header("We can send a authorization code to an email associated with your town account."))
	email, err := p.String("email to send reset code to?")
	if err != nil {
		return err
	}

	fmt.Println()
	fmt.Println(cs.Header("thanks!"))
	fmt.Println()
	fmt.Printf("If %s is associated with a town account we'll email an authorization code.\n", cs.Email(email))

	mustHave := []string{"@", "."}
	found := 0
	for _, s := range mustHave {
		if strings.Contains(email, s) {
			found++
		}
	}
	if found != len(mustHave) {
		// TODO log
		return nil
	}

	if _, err = emailToUsername(email); err != nil {
		// TODO log
		return nil
	}

	code := codes.NewCode(email)

	ac := &AuthCode{
		Code:  code,
		Email: email,
	}

	if err = ac.Insert(db); err != nil {
		// TODO log
		return err
	}

	if err = sendAuthCodeEmail(*ac); err != nil {
		// TODO log
		return err
	}

	return nil
}

func redeemCode(db *sql.DB, cs colorScheme, p *Prompter) error {
	fmt.Println(cs.Header("redeem an auth code and add a new public key"))
	fmt.Println()
	c, err := p.String("paste your auth code and hit enter to submit:")
	if err != nil {
		// TODO log
		fmt.Println(cs.Error("sorry, I couldn't read that."))
		return nil
	}

	parts, err := codes.Decode(c)
	if err != nil {
		// TODO log
		fmt.Println(cs.Error("sorry, that doesn't look like an auth code..."))
		return nil
	}

	code := &AuthCode{
		Code:  parts[0],
		Email: parts[1],
	}

	err = code.Hydrate(db)
	if err != nil {
		// TODO log
		return errors.New("the database is sad")
	}

	if code.Used {
		fmt.Println(cs.Error("That code has already been redeemed. You'll have to request a new one."))
		return nil
	}

	username, err := emailToUsername(code.Email)
	if err != nil {
		fmt.Println(cs.Error("That code doesn't seem to match an account."))
		// TODO log
		return nil
	}

	key, err := p.String("paste your new public key and hit enter to submit:")
	if err != nil {
		// TODO log
		fmt.Println(cs.Error("sorry, I couldn't read that."))
		return nil
	}

	valid, err := sshkey.ValidKey(key)
	if err != nil {
		return fmt.Errorf("failed to validate key: %w", err)
	}

	if !valid {
		errMsg := fmt.Sprintf("that key is invalid: %s", err.Error())
		fmt.Println(cs.Error(errMsg))
		return nil
	}

	cmd := exec.Command("sudo", "--user", username, "/town/bin/appendkeyfile", username)
	cmd.Stdin = bytes.NewBufferString(key)
	stdoutBuff := bytes.NewBuffer([]byte{})
	cmd.Stdout = stdoutBuff
	if err = cmd.Run(); err != nil {
		// TODO log error
		//return fmt.Errorf("appendkeyfile failed with '%s': %w", string(stdoutBuff.Bytes()), err)
		return errors.New("adding to keys file failed")
	}

	err = code.MarkUsed(db)
	if err != nil {
		// TODO log err
		return errors.New("database was sad")
	}

	return nil
}

// TODO db plan:

// add new db, codes (modeled after invites)
// add new helper, emailtouser, that can access town.db and report on what user matches a given email
// drop table from town.db
// update sshapps.md

func main() {
	cs := newColorScheme()
	err := _main(cs)
	if err != nil {
		fmt.Println(
			cs.Error(fmt.Sprintf("sorry, something went wrong: %s", err.Error())))
		fmt.Println("Please let an admin know by emailing a copy of this error to root@tilde.town")
		os.Exit(1)
	}
}

type AuthCode struct {
	ID      int64
	Code    string
	Email   string
	Used    bool
	Created time.Time
}

func (c *AuthCode) Insert(db *sql.DB) error {
	stmt, err := db.Prepare(`
	INSERT INTO auth_codes (code, email)
	VALUES ?, ?`)
	if err != nil {
		return err
	}

	defer stmt.Close()

	result, err := stmt.Exec(c.Code, c.Email)
	if err != nil {
		return err
	}

	liid, err := result.LastInsertId()
	if err != nil {
		return err
	}

	c.ID = liid

	return nil
}

func (c *AuthCode) Hydrate(db *sql.DB) error {
	stmt, err := db.Prepare(`
	SELECT id, used, created
	FROM auth_codes
	WHERE code = ? AND email = ?`)
	if err != nil {
		return err
	}
	defer stmt.Close()

	return stmt.QueryRow(c.Code).Scan(&c.ID, &c.Used, &c.Created)
}

func (c *AuthCode) MarkUsed(db *sql.DB) error {
	if c.ID == 0 {
		return errors.New("not hydrated")
	}

	stmt, err := db.Prepare(`
		UPDATE auth_codes SET used = 1 WHERE id = ?`)
	if err != nil {
		return err
	}
	defer stmt.Close()

	result, err := stmt.Exec(c.ID)
	if err != nil {
		return err
	}

	var rowsAffected int64

	if rowsAffected, err = result.RowsAffected(); err != nil {
		return err
	}

	if rowsAffected == 0 {
		return errors.New("no rows affected")
	}

	return nil
}