package form

import (
	"fmt"

	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
	"github.com/sjzar/chatlog/internal/ui/style"
)

const (
	// DialogPadding dialog inner padding.
	DialogPadding = 3

	// DialogHelpHeight dialog help text height.
	DialogHelpHeight = 1

	// DialogMinWidth dialog min width.
	DialogMinWidth = 40

	// FormHeightOffset form height offset for border.
	FormHeightOffset = 3

	// 额外的宽度补偿，类似于 submenu 的 cmdWidthOffset
	formWidthOffset = 10
)

// Form is a modal form component with a title, form fields, and help text.
type Form struct {
	*tview.Box
	title         string
	layout        *tview.Flex
	form          *tview.Form
	helpText      *tview.TextView
	width         int
	height        int
	cancelHandler func()
	fields        []formField // 存储字段信息以便重新计算宽度
}

// formField 存储表单字段的信息
type formField struct {
	label      string
	value      string
	fieldWidth int
}

// NewForm creates a new form with the given title.
func NewForm(title string) *Form {
	f := &Form{
		Box:    tview.NewBox(),
		title:  title,
		layout: tview.NewFlex().SetDirection(tview.FlexRow),
		form:   tview.NewForm(),
		fields: make([]formField, 0),
	}

	// 设置表单样式
	f.form.SetBorderPadding(1, 1, 1, 1)
	f.form.SetBackgroundColor(style.DialogBgColor)
	f.form.SetFieldBackgroundColor(style.BgColor)
	f.form.SetFieldTextColor(style.FgColor)
	f.form.SetButtonBackgroundColor(style.ButtonBgColor)
	f.form.SetButtonTextColor(style.FgColor)
	f.form.SetLabelColor(style.DialogFgColor)
	f.form.SetButtonsAlign(tview.AlignCenter)

	// 创建帮助文本
	f.helpText = tview.NewTextView()
	f.helpText.SetDynamicColors(true)
	f.helpText.SetTextAlign(tview.AlignCenter)
	f.helpText.SetTextColor(style.DialogFgColor)
	f.helpText.SetBackgroundColor(style.DialogBgColor)
	fmt.Fprintf(f.helpText,
		"[%s::b]Tab[%s::b]: 导航  [%s::b]Enter[%s::b]: 选择  [%s::b]ESC[%s::b]: 返回",
		style.GetColorHex(style.MenuBgColor), style.GetColorHex(style.PageHeaderFgColor),
		style.GetColorHex(style.MenuBgColor), style.GetColorHex(style.PageHeaderFgColor),
		style.GetColorHex(style.MenuBgColor), style.GetColorHex(style.PageHeaderFgColor),
	)

	// 创建布局
	formLayout := tview.NewFlex().SetDirection(tview.FlexColumn)
	formLayout.AddItem(EmptyBoxSpace(style.DialogBgColor), 1, 0, false)
	formLayout.AddItem(f.form, 0, 1, true)
	formLayout.AddItem(EmptyBoxSpace(style.DialogBgColor), 1, 0, false)

	// 设置主布局
	f.layout.SetTitle(fmt.Sprintf("[::b]%s", f.title))
	f.layout.SetTitleColor(style.DialogFgColor)
	f.layout.SetTitleAlign(tview.AlignCenter)
	f.layout.SetBorder(true)
	f.layout.SetBorderColor(style.DialogBorderColor)
	f.layout.SetBackgroundColor(style.DialogBgColor)

	// 添加表单区域
	f.layout.AddItem(formLayout, 0, 1, true)

	// 添加帮助文本区域
	f.layout.AddItem(f.helpText, DialogHelpHeight, 0, false)

	return f
}

// AddInputField adds an input field to the form.
func (f *Form) AddInputField(label, value string, fieldWidth int, accept func(textToCheck string, lastChar rune) bool, changed func(text string)) *Form {
	// 存储字段信息
	f.fields = append(f.fields, formField{
		label:      label,
		value:      value,
		fieldWidth: fieldWidth,
	})

	// 添加输入字段到表单
	f.form.AddInputField(label, value, fieldWidth, accept, changed)

	// 更新表单尺寸
	f.recalculateSize()

	return f
}

// AddButton adds a button to the form.
func (f *Form) AddButton(label string, selected func()) *Form {
	f.form.AddButton(label, selected)
	// 更新表单尺寸
	f.recalculateSize()
	return f
}

// AddCheckbox adds a checkbox to the form.
func (f *Form) AddCheckbox(label string, checked bool, changed func(checked bool)) *Form {
	f.form.AddCheckbox(label, checked, changed)
	// 更新表单尺寸
	f.recalculateSize()
	return f
}

// SetCancelFunc sets the function to be called when the form is cancelled.
func (f *Form) SetCancelFunc(handler func()) *Form {
	f.cancelHandler = handler
	return f
}

// recalculateSize 重新计算表单尺寸
func (f *Form) recalculateSize() {
	// 计算表单项数量
	itemCount := f.form.GetFormItemCount()

	// 计算高度 - 每个表单项占2行，按钮区域至少占2行，再加上边框和帮助文本
	f.height = (itemCount * 2) + 2 + FormHeightOffset + DialogHelpHeight

	// 计算宽度 - 类似于 submenu 的实现
	maxLabelWidth := 0
	maxValueWidth := 0

	// 遍历所有字段，找出最长的标签和值
	for _, field := range f.fields {
		if len(field.label) > maxLabelWidth {
			maxLabelWidth = len(field.label)
		}

		// 对于值，使用字段宽度和实际值长度中的较大者
		valueWidth := field.fieldWidth
		if len(field.value) > valueWidth {
			valueWidth = len(field.value)
		}

		if valueWidth > maxValueWidth {
			maxValueWidth = valueWidth
		}
	}

	// 计算总宽度，类似于 submenu 的计算方式
	f.width = maxLabelWidth + maxValueWidth + formWidthOffset

	// 确保宽度不小于最小值
	if f.width < DialogMinWidth {
		f.width = DialogMinWidth
	}
}

// Draw draws the form on the screen.
func (f *Form) Draw(screen tcell.Screen) {
	// 在绘制前重新计算尺寸，确保尺寸是最新的
	f.recalculateSize()

	// 绘制
	f.Box.DrawForSubclass(screen, f)
	f.layout.Draw(screen)
}

// SetRect sets the position and size of the form.
func (f *Form) SetRect(x, y, width, height int) {
	// 确保尺寸是最新的
	f.recalculateSize()

	// 类似于 submenu 的实现
	ws := (width - f.width) / 2
	hs := (height - f.height) / 2

	// 确保不会超出屏幕
	if f.width > width {
		ws = 0
		f.width = width - 1
	}

	if f.height > height {
		hs = 0
		f.height = height - 1
	}

	// 设置表单位置
	f.Box.SetRect(x+ws, y+hs, f.width, f.height)

	// 获取内部矩形并设置布局
	x, y, width, height = f.Box.GetInnerRect()
	f.layout.SetRect(x, y, width, height)
}

// Focus is called when this primitive receives focus.
func (f *Form) Focus(delegate func(p tview.Primitive)) {
	// 确保表单获得焦点
	if f.form != nil {
		delegate(f.form)
	} else {
		// 如果表单为空，则让Box获得焦点
		delegate(f.Box)
	}
}

// HasFocus returns whether or not this primitive has focus.
func (f *Form) HasFocus() bool {
	return f.form.HasFocus()
}

// InputHandler returns the handler for this primitive.
func (f *Form) InputHandler() func(event *tcell.EventKey, setFocus func(p tview.Primitive)) {
	return f.WrapInputHandler(func(event *tcell.EventKey, setFocus func(p tview.Primitive)) {
		// ESC键处理
		if event.Key() == tcell.KeyEscape && f.cancelHandler != nil {
			f.cancelHandler()
			return
		}

		// 将事件传递给表单
		if handler := f.form.InputHandler(); handler != nil {
			handler(event, setFocus)
		}
	})
}

// EmptyBoxSpace creates an empty box with the specified background color.
func EmptyBoxSpace(bgColor tcell.Color) *tview.Box {
	box := tview.NewBox()
	box.SetBackgroundColor(bgColor)
	box.SetBorder(false)
	return box
}