package banking

import (
	"fmt"
	"strings"

	"github.com/charmbracelet/lipgloss"
)

const termWidth = 80

// Color palette — green-on-black retro terminal.
var (
	colorGreen  = lipgloss.Color("#00FF00")
	colorDim    = lipgloss.Color("#007700")
	colorBlack  = lipgloss.Color("#000000")
	colorBright = lipgloss.Color("#AAFFAA")
	colorRed    = lipgloss.Color("#FF3333")
)

// Reusable styles.
var (
	baseStyle = lipgloss.NewStyle().
			Foreground(colorGreen).
			Background(colorBlack)

	headerStyle = lipgloss.NewStyle().
			Foreground(colorBright).
			Background(colorBlack).
			Bold(true).
			Width(termWidth).
			Align(lipgloss.Center)

	titleStyle = lipgloss.NewStyle().
			Foreground(colorGreen).
			Background(colorBlack).
			Bold(true)

	dimStyle = lipgloss.NewStyle().
			Foreground(colorDim).
			Background(colorBlack)

	errorStyle = lipgloss.NewStyle().
			Foreground(colorRed).
			Background(colorBlack).
			Bold(true)

	inputStyle = lipgloss.NewStyle().
			Foreground(colorBright).
			Background(colorBlack)
)

// divider returns an 80-column === line.
func divider() string {
	return dimStyle.Render(strings.Repeat("=", termWidth))
}

// thinDivider returns an 80-column --- line.
func thinDivider() string {
	return dimStyle.Render(strings.Repeat("-", termWidth))
}

// centerText centers text within 80 columns.
func centerText(s string) string {
	return headerStyle.Render(s)
}

// padRight pads a string to the given width.
func padRight(s string, width int) string {
	if len(s) >= width {
		return s[:width]
	}
	return s + strings.Repeat(" ", width-len(s))
}

// formatCurrency formats cents as $X,XXX.XX
func formatCurrency(cents int64) string {
	negative := cents < 0
	if negative {
		cents = -cents
	}
	dollars := cents / 100
	remainder := cents % 100

	// Add thousands separators.
	ds := fmt.Sprintf("%d", dollars)
	if len(ds) > 3 {
		var parts []string
		for len(ds) > 3 {
			parts = append([]string{ds[len(ds)-3:]}, parts...)
			ds = ds[:len(ds)-3]
		}
		parts = append([]string{ds}, parts...)
		ds = strings.Join(parts, ",")
	}

	if negative {
		return fmt.Sprintf("-$%s.%02d", ds, remainder)
	}
	return fmt.Sprintf("$%s.%02d", ds, remainder)
}

// padLine pads a single line (which may contain ANSI codes) to termWidth
// using its visual width. Padding uses a black background so the terminal's
// default background doesn't bleed through.
func padLine(line string) string {
	w := lipgloss.Width(line)
	if w >= termWidth {
		return line
	}
	return line + baseStyle.Render(strings.Repeat(" ", termWidth-w))
}

// padLines pads every line in a multi-line string to termWidth so that
// shorter lines fully overwrite previous content in the terminal.
func padLines(s string) string {
	lines := strings.Split(s, "\n")
	for i, line := range lines {
		lines[i] = padLine(line)
	}
	return strings.Join(lines, "\n")
}

// screenFrame wraps content in the persistent header and footer.
// The height parameter is used to pad the output to fill the terminal,
// preventing leftover lines from previous renders bleeding through.
func screenFrame(bankName, terminalID, region, content string, height int) string {
	var b strings.Builder

	// Header (4 lines).
	b.WriteString(divider())
	b.WriteString("\n")
	b.WriteString(centerText(bankName + " FEDERAL RESERVE SYSTEM"))
	b.WriteString("\n")
	b.WriteString(centerText("SECURE BANKING TERMINAL"))
	b.WriteString("\n")
	b.WriteString(divider())
	b.WriteString("\n")

	// Content.
	b.WriteString(content)

	// Pad with blank lines between content and footer so the footer
	// stays at the bottom and the total output fills the terminal height.
	if height > 0 {
		const headerLines = 4
		const footerLines = 2
		// strings.Count gives newlines; add 1 for the line after the last \n.
		contentLines := strings.Count(content, "\n") + 1
		used := headerLines + contentLines + footerLines
		blankLine := baseStyle.Render(strings.Repeat(" ", termWidth))
		for i := used; i < height; i++ {
			b.WriteString(blankLine)
			b.WriteString("\n")
		}
	}

	// Footer (2 lines).
	b.WriteString("\n")
	b.WriteString(divider())
	b.WriteString("\n")
	footer := fmt.Sprintf(" TERMINAL: %s | REGION: %s | ENCRYPTED SESSION ACTIVE", terminalID, region)
	b.WriteString(dimStyle.Render(padRight(footer, termWidth)))

	// Pad every line to full terminal width so shorter lines overwrite
	// leftover content from previous renders.
	return padLines(b.String())
}