package banking

import (
	"fmt"
	"strings"

	tea "github.com/charmbracelet/bubbletea"
)

const (
	transferStepRouting = iota
	transferStepDest
	transferStepBeneficiary
	transferStepBankName
	transferStepAmount
	transferStepMemo
	transferStepConfirm
	transferStepAuthCode
	transferStepComplete
)

var transferPrompts = []string{
	"  ROUTING NUMBER (ABA):  ",
	"  DESTINATION ACCOUNT:   ",
	"  BENEFICIARY NAME:      ",
	"  RECEIVING BANK NAME:   ",
	"  AMOUNT (USD):          ",
	"  MEMO / REFERENCE:      ",
	"",
	"  AUTHORIZATION CODE:    ",
}

type transferModel struct {
	step     int
	fields   [8]string // indexed by step
	transfer WireTransfer
	confirm  string // y/n input for confirm step
}

func newTransferModel() transferModel {
	return transferModel{}
}

func (m transferModel) Update(msg tea.Msg) (transferModel, tea.Cmd) {
	keyMsg, ok := msg.(tea.KeyMsg)
	if !ok {
		return m, nil
	}

	if m.step == transferStepComplete {
		return m, nil
	}

	if m.step == transferStepConfirm {
		switch keyMsg.Type {
		case tea.KeyEnter:
			switch strings.ToUpper(m.confirm) {
			case "Y", "YES":
				m.step = transferStepAuthCode
			case "N", "NO":
				m.confirm = "cancelled"
			}
			return m, nil
		case tea.KeyBackspace:
			if len(m.confirm) > 0 {
				m.confirm = m.confirm[:len(m.confirm)-1]
			}
		default:
			ch := keyMsg.String()
			if len(ch) == 1 && ch[0] >= 32 && ch[0] < 127 && len(m.confirm) < 3 {
				m.confirm += ch
			}
		}
		return m, nil
	}

	switch keyMsg.Type {
	case tea.KeyEnter:
		val := strings.TrimSpace(m.fields[m.step])
		if val == "" {
			return m, nil
		}
		if m.step == transferStepAuthCode {
			m.transfer.AuthCode = val
			m.step = transferStepComplete
			return m, nil
		}
		switch m.step {
		case transferStepRouting:
			m.transfer.RoutingNumber = val
		case transferStepDest:
			m.transfer.DestAccount = val
		case transferStepBeneficiary:
			m.transfer.Beneficiary = val
		case transferStepBankName:
			m.transfer.BankName = val
		case transferStepAmount:
			m.transfer.Amount = val
		case transferStepMemo:
			m.transfer.Memo = val
		}
		m.step++
		return m, nil
	case tea.KeyBackspace:
		if len(m.fields[m.step]) > 0 {
			m.fields[m.step] = m.fields[m.step][:len(m.fields[m.step])-1]
		}
	default:
		ch := keyMsg.String()
		if len(ch) == 1 && ch[0] >= 32 && ch[0] < 127 && len(m.fields[m.step]) < 40 {
			m.fields[m.step] += ch
		}
	}
	return m, nil
}

func (m transferModel) View() string {
	var b strings.Builder

	b.WriteString("\n")
	b.WriteString(centerText("WIRE TRANSFER"))
	b.WriteString("\n\n")
	b.WriteString(thinDivider())
	b.WriteString("\n\n")

	// Show completed fields.
	for i := 0; i < m.step && i < len(transferPrompts); i++ {
		if i == transferStepConfirm {
			continue
		}
		prompt := transferPrompts[i]
		if prompt == "" {
			continue
		}
		b.WriteString(baseStyle.Render(prompt))
		b.WriteString(baseStyle.Render(m.fields[i]))
		b.WriteString("\n")
	}

	// Current field.
	switch {
	case m.step == transferStepConfirm:
		b.WriteString("\n")
		b.WriteString(titleStyle.Render("  === TRANSFER SUMMARY ==="))
		b.WriteString("\n\n")
		b.WriteString(baseStyle.Render(fmt.Sprintf("  ROUTING:     %s", m.transfer.RoutingNumber)))
		b.WriteString("\n")
		b.WriteString(baseStyle.Render(fmt.Sprintf("  ACCOUNT:     %s", m.transfer.DestAccount)))
		b.WriteString("\n")
		b.WriteString(baseStyle.Render(fmt.Sprintf("  BENEFICIARY: %s", m.transfer.Beneficiary)))
		b.WriteString("\n")
		b.WriteString(baseStyle.Render(fmt.Sprintf("  BANK:        %s", m.transfer.BankName)))
		b.WriteString("\n")
		b.WriteString(baseStyle.Render(fmt.Sprintf("  AMOUNT:      $%s", m.transfer.Amount)))
		b.WriteString("\n")
		b.WriteString(baseStyle.Render(fmt.Sprintf("  MEMO:        %s", m.transfer.Memo)))
		b.WriteString("\n\n")
		b.WriteString(titleStyle.Render("  CONFIRM TRANSFER? (Y/N): "))
		b.WriteString(inputStyle.Render(m.confirm))
		b.WriteString(inputStyle.Render("_"))
		b.WriteString("\n")
	case m.step == transferStepComplete:
		b.WriteString("\n")
		b.WriteString(thinDivider())
		b.WriteString("\n\n")
		b.WriteString(titleStyle.Render("  TRANSFER QUEUED FOR PROCESSING"))
		b.WriteString("\n\n")
		b.WriteString(baseStyle.Render(fmt.Sprintf("  CONFIRMATION #: WR-%s-%s",
			m.transfer.RoutingNumber[:4], "847291")))
		b.WriteString("\n")
		b.WriteString(baseStyle.Render("  STATUS: PENDING FEDWIRE SETTLEMENT"))
		b.WriteString("\n")
		b.WriteString(baseStyle.Render("  ESTIMATED COMPLETION: NEXT BUSINESS DAY"))
		b.WriteString("\n\n")
		b.WriteString(dimStyle.Render("  PRESS ANY KEY TO RETURN TO MAIN MENU"))
		b.WriteString("\n")
	case m.step < len(transferPrompts):
		prompt := transferPrompts[m.step]
		b.WriteString(titleStyle.Render(prompt))
		b.WriteString(inputStyle.Render(m.fields[m.step]))
		b.WriteString(inputStyle.Render("_"))
		b.WriteString("\n")
	}

	if m.step < transferStepConfirm {
		b.WriteString("\n")
		b.WriteString(thinDivider())
		b.WriteString("\n\n")
		b.WriteString(dimStyle.Render(fmt.Sprintf("  STEP %d OF 6", m.step+1)))
		b.WriteString("\n")
	}

	return b.String()
}