package main

import (
	"fmt"
	"path/filepath"
	"strings"

	"github.com/charmbracelet/bubbles/list"
	"github.com/charmbracelet/bubbles/progress"
	"github.com/charmbracelet/bubbles/spinner"
	tea "github.com/charmbracelet/bubbletea"
)

// --- Version Select Page ---

func updateVersionSelect(m model, msg tea.Msg) (model, tea.Cmd) {
	switch msg := msg.(type) {
	case versionsFoundMsg:
		items := make([]list.Item, len(msg))
		for i, v := range msg {
			items[i] = versionItem{name: v.name, path: v.path}
		}
		m.logLines = nil // Bug3: 清除旧的扫描错误，否则 view 永远显示错误
		m.versionList.SetItems(items)
		return m, nil

	case scanErrorMsg:
		m.logLines = []string{errorStyle.Render("扫描版本目录失败: " + msg.err.Error())}
		return m, nil

	case tea.KeyMsg:
		if msg.String() == "enter" {
			selected, ok := m.versionList.SelectedItem().(versionItem)
			if ok {
				m.versionDir = selected.path
				m.versionName = selected.name
				m.currentPage = pageMainMenu
				m.logLines = nil // Bug1: 清除版本选择页的 logLines
				m.menuList.SetItems([]list.Item{
					menuItem{title: "输入数字码", desc: "输入工具码以执行操作"},
					menuItem{title: "切换版本", desc: "选择其他游戏版本"},
				})
				return m, nil
			}
		}
	}

	var cmd tea.Cmd
	m.versionList, cmd = m.versionList.Update(msg)
	return m, cmd
}

func viewVersionSelect(m model) string {
	if len(m.logLines) > 0 {
		return "\n" + strings.Join(m.logLines, "\n") + "\n\n" + subtleStyle.Render("按 ctrl+c 退出")
	}
	return m.versionList.View()
}

// --- Main Menu Page ---

func updateMainMenu(m model, msg tea.Msg) (model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "enter":
			idx := m.menuList.Index()
			switch idx {
			case 0:
				m.currentPage = pageCodeInput
				m.codeInput.SetValue("")
				return m, m.codeInput.Focus()
			case 1:
				m.currentPage = pageVersionSelect
				m.logLines = nil            // Bug2: 清除残留 logLines，否则版本列表被错误文本遮挡
				m.versionList.SetItems(nil) // Bug10: 清除旧列表，避免短暂显示过时数据
				return m, scanVersions(m.exeDir)
			}
		case "esc", "q":
			return m, tea.Quit
		}
	}

	var cmd tea.Cmd
	m.menuList, cmd = m.menuList.Update(msg)
	return m, cmd
}

func viewMainMenu(m model) string {
	header := subtleStyle.Render(fmt.Sprintf("当前版本: %s", m.versionName))
	return header + "\n" + m.menuList.View()
}

// --- Code Input Page ---

func updateCodeInput(m model, msg tea.Msg) (model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "enter":
			code := m.codeInput.Value()
			if len(code) == 4 {
				m.currentPage = pageExecuting
				m = resetExecState(m)
				return m, tea.Batch(m.spinner.Tick, fetchActions(code))
			}
		case "esc":
			m.currentPage = pageMainMenu
			return m, nil
		}
	}

	var cmd tea.Cmd
	m.codeInput, cmd = m.codeInput.Update(msg)
	return m, cmd
}

func viewCodeInput(m model) string {
	return fmt.Sprintf(
		"%s\n\n  输入4位数字码:\n\n  %s\n\n  %s\n",
		appTitle,
		m.codeInput.View(),
		subtleStyle.Render("enter 确认 | esc 返回"),
	)
}

// --- Executing Page ---

type actionProgressMsg struct {
	percent float64
	message string
}
type actionCompleteMsg struct{ index int }
type actionErrorMsg struct {
	index int
	err   error
}
type mirrorChoiceMsg struct {
	index   int
	mirrors []string
	action  Action
}

func updateExecuting(m model, msg tea.Msg) (model, tea.Cmd) {
	if m.choosingMirror {
		return updateMirrorChoice(m, msg)
	}

	switch msg := msg.(type) {
	case actionsReceivedMsg:
		m.actions = msg.actions
		m.actionIdx = 0
		if len(m.actions) == 0 {
			m.execDone = true
			m.logLines = append(m.logLines, successStyle.Render("没有需要执行的操作"))
			return m, nil
		}
		m.backupDir = newBackupDir()
		m.logLines = append(m.logLines, boldStyle.Render(fmt.Sprintf("共 %d 个操作", len(m.actions))))
		m.logLines = append(m.logLines, describeAction(m.actions[0], 0, len(m.actions)))
		return m, tea.Batch(m.spinner.Tick, executeAction(m.versionDir, m.actions[0], 0, m.backupDir))

	case apiErrorMsg:
		m.execErr = msg.err
		m.logLines = append(m.logLines, crossMark+" "+errorStyle.Render("API 请求失败: "+msg.err.Error()))
		return m, nil

	case actionProgressMsg:
		if msg.message != "" {
			m.logLines = append(m.logLines, msg.message)
		}
		cmd := m.progress.SetPercent(msg.percent)
		var cmds []tea.Cmd
		cmds = append(cmds, cmd)
		if m.progressCh != nil {
			cmds = append(cmds, waitForProgress(m.progressCh, m.actionIdx))
		}
		return m, tea.Batch(cmds...)

	case actionCompleteMsg:
		m.progressCh = nil
		total := len(m.actions)
		m.logLines = append(m.logLines, fmt.Sprintf("%s [%d/%d] 完成", checkMark, msg.index+1, total))

		if msg.index+1 >= total {
			m.execDone = true
			m.logLines = append(m.logLines, "\n"+successStyle.Render("全部操作完成!"))
			return m, m.progress.SetPercent(1.0)
		}

		m.actionIdx = msg.index + 1
		m.logLines = append(m.logLines, describeAction(m.actions[m.actionIdx], m.actionIdx, total))
		progressCmd := m.progress.SetPercent(float64(m.actionIdx) / float64(total))
		return m, tea.Batch(
			progressCmd,
			executeAction(m.versionDir, m.actions[m.actionIdx], m.actionIdx, m.backupDir),
		)

	case actionErrorMsg:
		m.progressCh = nil
		m.execErr = msg.err
		m.logLines = append(m.logLines, fmt.Sprintf("%s [%d/%d] 失败: %s", crossMark, msg.index+1, len(m.actions), msg.err.Error()))
		if m.backupDir != "" {
			m.logLines = append(m.logLines, subtleStyle.Render("备份目录: "+filepath.Join(m.versionDir, m.backupDir)))
		}
		return m, nil

	case mirrorChoiceMsg:
		m.progressCh = nil
		m.choosingMirror = true
		m.pendingAction = &msg.action
		items := make([]list.Item, len(msg.mirrors))
		for i, u := range msg.mirrors {
			items[i] = mirrorItem{url: u}
		}
		delegate := list.NewDefaultDelegate()
		l := list.New(items, delegate, m.width, m.height-6)
		l.Title = "主 URL 下载失败，请选择镜像源"
		l.SetFilteringEnabled(false)
		l.SetShowStatusBar(false)
		m.mirrorList = l
		return m, nil

	case tea.KeyMsg:
		if m.execDone || m.execErr != nil {
			m.currentPage = pageMainMenu
			m = resetExecState(m)
			return m, nil
		}

	case spinner.TickMsg:
		var cmd tea.Cmd
		m.spinner, cmd = m.spinner.Update(msg)
		return m, cmd

	case progress.FrameMsg:
		p, cmd := m.progress.Update(msg)
		m.progress = p.(progress.Model)
		return m, cmd
	}

	return m, nil
}

func updateMirrorChoice(m model, msg tea.Msg) (model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		if msg.String() == "enter" {
			selected, ok := m.mirrorList.SelectedItem().(mirrorItem)
			if ok && m.pendingAction != nil {
				m.choosingMirror = false
				action := *m.pendingAction
				action.URL = selected.url
				m.pendingAction = nil
				m.logLines = append(m.logLines, subtleStyle.Render("使用镜像: "+selected.url))
				return m, executeAction(m.versionDir, action, m.actionIdx, m.backupDir)
			}
		}
		if msg.String() == "esc" {
			m.choosingMirror = false
			m.pendingAction = nil
			m.execErr = fmt.Errorf("用户取消镜像选择")
			m.logLines = append(m.logLines, crossMark+" "+errorStyle.Render("已取消"))
			return m, nil
		}
	}

	var cmd tea.Cmd
	m.mirrorList, cmd = m.mirrorList.Update(msg)
	return m, cmd
}

func viewExecuting(m model) string {
	if m.choosingMirror {
		return m.mirrorList.View()
	}

	var sb strings.Builder
	sb.WriteString(appTitle)
	sb.WriteString("\n\n")

	for _, line := range m.logLines {
		sb.WriteString("  ")
		sb.WriteString(line)
		sb.WriteString("\n")
	}

	if !m.execDone && m.execErr == nil && len(m.actions) > 0 {
		sb.WriteString("\n")
		sb.WriteString(fmt.Sprintf("  %s 正在执行 [%d/%d]...\n", m.spinner.View(), m.actionIdx+1, len(m.actions)))
		sb.WriteString("\n  ")
		sb.WriteString(m.progress.View())
		sb.WriteString("\n")
	}

	if m.execDone || m.execErr != nil {
		sb.WriteString("\n  ")
		sb.WriteString(subtleStyle.Render("按任意键返回主菜单"))
		sb.WriteString("\n")
	}

	return sb.String()
}

func resetExecState(m model) model {
	m.actions = nil
	m.actionIdx = 0
	m.logLines = nil
	m.execErr = nil
	m.execDone = false
	m.choosingMirror = false
	m.pendingAction = nil
	m.backupDir = ""
	m.progressCh = nil
	return m
}

func describeAction(a Action, idx, total int) string {
	prefix := fmt.Sprintf("[%d/%d]", idx+1, total)
	switch a.Type {
	case "add":
		if a.Unzip {
			return subtleStyle.Render(fmt.Sprintf("%s 下载并解压 %s ...", prefix, a.Path))
		}
		return subtleStyle.Render(fmt.Sprintf("%s 下载 %s ...", prefix, a.Path))
	case "delete":
		return subtleStyle.Render(fmt.Sprintf("%s 删除 %s ...", prefix, a.Path))
	case "copy":
		return subtleStyle.Render(fmt.Sprintf("%s 复制 %s -> %s ...", prefix, a.Path, a.NewPath))
	case "move":
		return subtleStyle.Render(fmt.Sprintf("%s 移动 %s -> %s ...", prefix, a.Path, a.NewPath))
	case "new":
		if a.IsDir {
			return subtleStyle.Render(fmt.Sprintf("%s 新建文件夹 %s ...", prefix, a.Path))
		}
		return subtleStyle.Render(fmt.Sprintf("%s 新建文件 %s ...", prefix, a.Path))
	default:
		return subtleStyle.Render(fmt.Sprintf("%s %s %s ...", prefix, a.Type, a.Path))
	}
}