package tui

import (
    "fmt"
    "strings"

    "charm.land/lipgloss/v2"
)

// AccessibilityHelper provides accessibility features like screen reader support.
type AccessibilityHelper struct {
    isDark      bool
    styles      AccessibilityStyles
    speakFunc   func(string) // Function to speak text (for screen readers)
    announceFunc func(string) // Function to announce changes
}

// AccessibilityStyles holds styling.
type AccessibilityStyles struct {
    Announce lipgloss.Style
}

// DefaultAccessibilityStyles returns default styles.
func DefaultAccessibilityStyles(isDark bool) AccessibilityStyles {
    return AccessibilityStyles{
        Announce: lipgloss.NewStyle().Foreground(lipgloss.Color("#88c0d0")),
    }
}

// NewAccessibilityHelper creates a new accessibility helper.
func NewAccessibilityHelper(isDark bool) *AccessibilityHelper {
    return &AccessibilityHelper{
        isDark:  isDark,
        styles:  DefaultAccessibilityStyles(isDark),
    }
}

// SetDark updates theme.
func (ah *AccessibilityHelper) SetDark(isDark bool) {
    ah.isDark = isDark
    ah.styles = DefaultAccessibilityStyles(isDark)
}

// SetSpeakFunc sets the function to speak text.
func (ah *AccessibilityHelper) SetSpeakFunc(f func(string)) {
    ah.speakFunc = f
}

// SetAnnounceFunc sets the function to announce changes.
func (ah *AccessibilityHelper) SetAnnounceFunc(f func(string)) {
    ah.announceFunc = f
}

// Announce announces a message to the user.
func (ah *AccessibilityHelper) Announce(format string, args ...string) {
    if ah.announceFunc != nil {
        msg := format
        if len(args) > 0 {
            msg = fmt.Sprintf(format, args)
        }
        ah.announceFunc(msg)
    }
}

// Speak speaks text directly.
func (ah *AccessibilityHelper) Speak(text string) {
    if ah.speakFunc != nil {
        ah.speakFunc(text)
    }
}

// DescribeEntry creates an accessibility description for a chat entry.
func (ah *AccessibilityHelper) DescribeEntry(entry ChatEntry, index int, toolCount int) string {
    var desc strings.Builder

    switch entry.Kind {
    case "user":
        desc.WriteString("User message")
    case "assistant":
        desc.WriteString("Assistant response")
        if entry.ThinkingContent != "" {
            desc.WriteString(", has thinking")
        }
    case "tool_group":
        desc.WriteString("Tool execution")
        if index >= 0 && index < toolCount {
            desc.WriteString(", tool result")
        }
    case "system":
        desc.WriteString("System message")
    case "error":
        desc.WriteString("Error")
    }

    // Add content preview
    if entry.Content != "" {
        preview := truncateStr(entry.Content, 50)
        desc.WriteString(": ")
        desc.WriteString(preview)
    }

    return desc.String()
}

// DescribeState creates an accessibility description of the current state.
func (ah *AccessibilityHelper) DescribeState(state State, model, mode string) string {
    var desc string

    switch state {
    case StateIdle:
        desc = "Ready"
    case StateWaiting:
        desc = "Waiting for response"
    case StateStreaming:
        desc = "Receiving response"
    }

    if model != "" {
        desc += ", model: " + model
    }
    if mode != "" {
        desc += ", mode: " + mode
    }

    return desc
}

// DescribeOverlay creates an accessibility description of the current overlay.
func (ah *AccessibilityHelper) DescribeOverlay(overlay OverlayKind) string {
    switch overlay {
    case OverlayNone:
        return ""
    case OverlayHelp:
        return "Help overlay open"
    case OverlayCompletion:
        return "Completion menu open"
    case OverlayModelPicker:
        return "Model picker open"
    case OverlayPlanForm:
        return "Plan form open"
    case OverlaySessionsPicker:
        return "Sessions picker open"
    default:
        return "Overlay open"
    }
}

// DescribeTools creates an accessibility description of tool status.
func (ah *AccessibilityHelper) DescribeTools(pending, total int) string {
    if pending == 0 && total == 0 {
        return "No tools running"
    }
    if pending > 0 {
        return fmt.Sprintf("%d tool running", pending)
    }
    return fmt.Sprintf("%d tools completed", total)
}

// truncate truncates a string to maxLength.
func truncateStr(s string, maxLength int) string {
    if len(s) <= maxLength {
        return s
    }
    return s[:maxLength-3] + "..."
}

// AccessibilityLabel returns an accessibility label for a view element.
func AccessibilityLabel(role, name string, props ...string) string {
    var b strings.Builder
    b.WriteString(role)
    b.WriteString(": ")
    b.WriteString(name)

    for _, p := range props {
        b.WriteString(", ")
        b.WriteString(p)
    }

    return b.String()
}

// FocusOrder represents the focus order for keyboard navigation.
type FocusOrder struct {
    Current int
    Items   []Focusable
}

// Focusable is an interface for focusable elements.
type Focusable interface {
    Focus() error
    Blur() error
    IsFocused() bool
}

// NewFocusOrder creates a new focus order.
func NewFocusOrder(items []Focusable) *FocusOrder {
    return &FocusOrder{
        Current: 0,
        Items:   items,
    }
}

// Next moves focus to the next item.
func (fo *FocusOrder) Next() {
    if len(fo.Items) == 0 {
        return
    }
    fo.Current = (fo.Current + 1) % len(fo.Items)
    fo.focusCurrent()
}

// Prev moves focus to the previous item.
func (fo *FocusOrder) Prev() {
    if len(fo.Items) == 0 {
        return
    }
    fo.Current--
    if fo.Current < 0 {
        fo.Current = len(fo.Items) - 1
    }
    fo.focusCurrent()
}

// Current returns the currently focused item.
func (fo *FocusOrder) CurrentItem() Focusable {
    if fo.Current >= 0 && fo.Current < len(fo.Items) {
        return fo.Items[fo.Current]
    }
    return nil
}

func (fo *FocusOrder) focusCurrent() {
    for i, item := range fo.Items {
        if i == fo.Current {
            item.Focus()
        } else {
            item.Blur()
        }
    }
}