package add

import (
	"errors"
	"fmt"
	"log"
	"os"
	"strings"
	"time"

	"github.com/charmbracelet/bubbles/help"
	"github.com/charmbracelet/bubbles/key"
	"github.com/charmbracelet/bubbles/textinput"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
	"github.com/spf13/cobra"

	"github.com/tgrosinger/ledger-tui/pkg/tui/currencyinput"
	"github.com/tgrosinger/ledger-tui/pkg/tui/dateinput"
	"github.com/tgrosinger/ledger-tui/pkg/tui/postingsinput"
	"github.com/tgrosinger/ledger-tui/pkg/tui/suggestions"
)

var AddCmd = &cobra.Command{
	Use:   "add",
	Short: "Add a new transaction to a ledger file",
	Args:  cobra.NoArgs,
	Run:   executeAddTUI,
}

func executeAddTUI(cmd *cobra.Command, args []string) {
	f, err := cmd.Flags().GetString("file")
	if err != nil {
		log.Fatalf("Missing ledger file path: %s", err.Error())
	}
	log.Println("Using ledger file in " + f)

	addTUI := AddTxTUI{
		focused:       date,
		furthestFocus: date,
		date:          dateinput.New(time.Now(), true),
		description:   textinput.New(),
		total:         currencyinput.New("$"),
		suggestionBox: suggestions.New(f),
		help:          help.New(),
		keymap: keymap{
			nextField: key.NewBinding(
				key.WithKeys("tab"),
				key.WithHelp("tab", "Next")),
			prevField: key.NewBinding(
				key.WithKeys("shift+tab"),
				key.WithHelp("shift+tab", "Previous")),
			quit: key.NewBinding(
				key.WithKeys("esc", "ctrl+c"),
				key.WithHelp("esc", "Quit")),
		},
	}

	addTUI.description.Placeholder = "Transaction Description"
	addTUI.description.Validate = descriptionValidator
	addTUI.description.Prompt = ""

	p := tea.NewProgram(addTUI, tea.WithAltScreen())
	if err := p.Start(); err != nil {
		fmt.Printf("Alas, there's been an error: %v", err)
		os.Exit(1)
	}
}

func descriptionValidator(s string) error {
	// The description must not have a line break
	if strings.Contains(s, "\n") {
		return errors.New("description must not contain a new line")
	}
	return nil
}

type focus int

const (
	none focus = iota
	date
	description
	total
	lines
)

type keymap struct {
	nextField key.Binding
	prevField key.Binding
	//increment key.Binding
	//decrement key.Binding
	quit key.Binding
}

type AddTxTUI struct {
	// Add New Tx Form
	focused       focus
	furthestFocus focus

	// Fields
	date        dateinput.Model
	description textinput.Model
	total       currencyinput.Model

	suggestionBox suggestions.Model

	keymap keymap
	help   help.Model

	// halfFrame is a style which can fit two side by side, separated by a
	// simple border. Will be resized when the window resizes.
	halfFrame lipgloss.Style
}

func (m AddTxTUI) Init() tea.Cmd {
	return tea.Batch(
		m.date.Init(),
		m.total.Init(),
		m.suggestionBox.Init(),
	)
}

func (m AddTxTUI) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	cmds := make([]tea.Cmd, 3)

	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.halfFrame = lipgloss.NewStyle().
			Width((msg.Width/2)-2).
			Height(msg.Height-4).
			Border(lipgloss.NormalBorder(), true)
	case dateinput.Msg:
		switch msg {
		case dateinput.NextInputMsg:
			if m.focused == date {
				log.Println("Focusing description")
				m.focused = description
			}
		case dateinput.PrevInputMsg:
			// No input field before date, so ignore
		}
	case postingsinput.Msg:
		switch msg {
		case postingsinput.NextInputMsg:
			if m.focused == lines {
				// TODO: Focus on save button
			}
		case postingsinput.PrevInputMsg:
			if m.focused == lines {
				m.focused = total
			}
		}
	case tea.KeyMsg:
		switch msg.Type {

		// These keys should exit the program.
		case tea.KeyCtrlC, tea.KeyEsc:
			return m, tea.Quit

		// Navigate between fields
		case tea.KeyTab:
			if m.focused == description {
				m.focused = total
			} else if m.focused == total {
				m.focused = lines
			}
		case tea.KeyShiftTab:
			if m.focused == description {
				m.focused = date
			} else if m.focused == total {
				m.focused = description
			}
		}
	}

	m.setFocus()

	var cmd tea.Cmd
	m.date, cmd = m.date.Update(msg)
	cmds = append(cmds, cmd)
	m.description, cmd = m.description.Update(msg)
	cmds = append(cmds, cmd)
	m.total, cmd = m.total.Update(msg)
	cmds = append(cmds, cmd)
	m.suggestionBox, cmd = m.suggestionBox.Update(msg)
	cmds = append(cmds, cmd)

	return m, tea.Batch(cmds...)
}

func (m *AddTxTUI) setFocus() {
	if m.focused != date && m.date.Focused() {
		m.date.Blur()
	}
	if m.focused != description && m.description.Focused() {
		m.description.Blur()
	}
	if m.focused != total && m.total.Focused() {
		m.total.Blur()
	}
	// TODO: Blur accounts

	switch m.focused {
	case date:
		m.date.Focus()
		if m.furthestFocus < date {
			m.furthestFocus = date
		}
	case description:
		m.description.Focus()
		if m.furthestFocus < description {
			m.furthestFocus = description
		}
	case total:
		m.total.Focus()
		if m.furthestFocus < total {
			m.furthestFocus = total
		}
	case lines:
		// TODO: Focus accounts
		if m.furthestFocus < lines {
			m.furthestFocus = lines
		}
	}
}

func (m AddTxTUI) helpView() string {
	return "\n" + m.help.ShortHelpView([]key.Binding{
		m.keymap.nextField,
		m.keymap.prevField,
		m.keymap.quit,
	})
}

func (m AddTxTUI) View() string {
	output := strings.Builder{}
	output.WriteString("Date: " + m.date.View())

	if m.furthestFocus >= description {
		output.WriteString("\nDesc: " + m.description.View())
	}

	if m.furthestFocus >= total {
		output.WriteString("\nTotal: " + m.total.View())

	}

	return lipgloss.JoinVertical(lipgloss.Left,
		lipgloss.JoinHorizontal(lipgloss.Top,
			m.halfFrame.Render(output.String()),
			m.halfFrame.Render(m.suggestionBox.View())),
		m.helpView(),
	)
}