package toolinstaller

import (
	"bytes"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"ezops/model"

	"gorm.io/gorm"
)

// ToolInstaller handles lazy installation of devops tools.
// Each tool gets a sync.Once to prevent concurrent installations.
type ToolInstaller struct {
	db     *gorm.DB
	onces  map[string]*sync.Once
	mu     sync.Mutex
}

// New creates a ToolInstaller.
func New(db *gorm.DB) *ToolInstaller {
	return &ToolInstaller{
		db:    db,
		onces: make(map[string]*sync.Once),
	}
}

// ensureOnce returns a sync.Once for the given tool name.
func (ti *ToolInstaller) ensureOnce(name string) *sync.Once {
	ti.mu.Lock()
	defer ti.mu.Unlock()
	if o, ok := ti.onces[name]; ok {
		return o
	}
	o := &sync.Once{}
	ti.onces[name] = o
	return o
}

// InstallResult 工具安装结果（含脚本输出，供审计日志）// Logan.Li
type InstallResult struct {
	Output      string
	VerifyOut   string
	Installed   bool
	Version     string
	Err         error
}

// ForceInstall unconditionally installs a tool（重置 Once，允许重复安装）// Logan.Li
func (ti *ToolInstaller) ForceInstall(toolName string, version string) InstallResult {
	var tool model.DeployTool
	if err := ti.db.Where("name = ?", toolName).First(&tool).Error; err != nil {
		return InstallResult{Err: fmt.Errorf("tool %s not found in DB: %w", toolName, err)}
	}

	ti.mu.Lock()
	delete(ti.onces, toolName)
	ti.mu.Unlock()

	// Override version if specified
	if version != "" && version != tool.DefaultVersion {
		ti.db.Model(&tool).Update("default_version", version)
		tool.DefaultVersion = version
	}

	return ti.installTool(&tool)
}

// EnsureAvailable checks if a tool is available and installs it if configured for lazy loading.
// Returns nil if the tool is ready, or an error if installation failed.
func (ti *ToolInstaller) EnsureAvailable(toolName string) error {
	// Find tool in DB
	var tool model.DeployTool
	if err := ti.db.Where("name = ?", toolName).First(&tool).Error; err != nil {
		// Tool not in DB — try to find it by path
		if _, lookErr := exec.LookPath(toolName); lookErr == nil {
			return nil // available even without DB config
		}
		return fmt.Errorf("tool %s not configured in DB", toolName)
	}

	if !tool.Enabled {
		return fmt.Errorf("tool %s is disabled", toolName)
	}

	// Check if already installed
	if tool.InstallMethod == model.ToolPreinstall || tool.InstallMethod == model.ToolLazy {
		if inst, err := ti.checkInstalled(tool); err == nil {
			// Update status if needed
			if tool.Status != model.ToolInstalled {
				ti.updateStatus(tool.ID, model.ToolInstalled, inst, "")
			}
			return nil
		}
	}

	switch tool.InstallMethod {
	case model.ToolPreinstall:
		return fmt.Errorf("tool %s should be preinstalled but not found", toolName)
	case model.ToolDisabled:
		return fmt.Errorf("tool %s is disabled", toolName)
	case model.ToolLazy:
		// Use sync.Once to prevent concurrent installs
		var installErr error
		once := ti.ensureOnce(toolName)
		once.Do(func() {
			res := ti.installTool(&tool)
			installErr = res.Err
		})
		// If install failed, reset the Once so next call can retry
		if installErr != nil {
			ti.mu.Lock()
			delete(ti.onces, toolName)
			ti.mu.Unlock()
		}
		return installErr
	default:
		return fmt.Errorf("unknown install method: %s", tool.InstallMethod)
	}
}

// VerifyTool 检测工具是否已安装（文件存在 + 可执行验证，不依赖 PATH）// Logan.Li
func (ti *ToolInstaller) VerifyTool(tool model.DeployTool) (bool, string) {
	switch tool.Name {
	case "jdk":
		for _, p := range []string{"/usr/local/bin/java", "/usr/local/share/jdk/bin/java"} {
			if st, err := os.Stat(p); err == nil && !st.IsDir() {
				cmd := exec.Command(p, "-version")
				out, _ := cmd.CombinedOutput()
				ver := strings.TrimSpace(strings.Split(string(out), "\n")[0])
				if ver != "" {
					return true, ver
				}
				return true, "installed"
			}
		}
	case "maven":
		for _, p := range []string{"/usr/local/bin/mvn", "/usr/local/share/maven/bin/mvn"} {
			if st, err := os.Stat(p); err == nil && !st.IsDir() {
				cmd := exec.Command(p, "--version")
				out, err := cmd.Output()
				if err == nil {
					return true, strings.TrimSpace(strings.Split(string(out), "\n")[0])
				}
				return true, "installed"
			}
		}
	case "nvm":
		nvmSh := "/usr/local/share/nvm/nvm.sh"
		if st, err := os.Stat(nvmSh); err == nil && !st.IsDir() {
			cmd := exec.Command("bash", "-c", fmt.Sprintf(`. "%s" && nvm --version`, nvmSh))
			out, err := cmd.Output()
			if err == nil {
				return true, strings.TrimSpace(string(out))
			}
			return true, tool.DefaultVersion
		}
	case "golang":
		for _, p := range []string{"/usr/local/bin/go", "/usr/local/go/bin/go"} {
			if st, err := os.Stat(p); err == nil && !st.IsDir() {
				cmd := exec.Command(p, "version")
				out, _ := cmd.CombinedOutput()
				ver := strings.TrimSpace(string(out))
				if ver != "" {
					return true, ver
				}
				return true, "installed"
			}
		}
	case "nodejs":
		for _, p := range []string{"/usr/local/bin/node"} {
			if st, err := os.Stat(p); err == nil && !st.IsDir() {
				cmd := exec.Command(p, "--version")
				out, _ := cmd.CombinedOutput()
				ver := strings.TrimSpace(string(out))
				if ver != "" {
					return true, ver
				}
				return true, "installed"
			}
		}
	default:
		if ver, err := ti.runToolCheck(tool); err == nil {
			return true, ver
		}
	}
	return false, ""
}

// SyncToolStatus 根据磁盘实际状态刷新 DB（修复审计成功但页面仍失败/安装中）// Logan.Li
func (ti *ToolInstaller) SyncToolStatus(toolID uint) model.DeployTool {
	var tool model.DeployTool
	if err := ti.db.First(&tool, toolID).Error; err != nil {
		return tool
	}
	ok, ver := ti.VerifyTool(tool)
	if ok {
		ti.updateStatus(tool.ID, model.ToolInstalled, ver, "")
		tool.Status = model.ToolInstalled
		tool.InstalledVer = ver
		tool.ErrorMsg = ""
	} else if tool.Status == model.ToolInstalling {
		// 保持安装中，由超时逻辑处理
	} else if tool.Status == model.ToolInstalled {
		// 已标记安装但文件不存在 — 降为未安装
		ti.updateStatus(tool.ID, model.ToolNotInstalled, "", "")
		tool.Status = model.ToolNotInstalled
	}
	ti.db.First(&tool, toolID)
	return tool
}

// runToolCheck 执行 PATH/检测命令（不回调 VerifyTool，避免递归栈溢出）// Logan.Li
func (ti *ToolInstaller) runToolCheck(tool model.DeployTool) (string, error) {
	if tool.BinaryName != "" && tool.BinaryName != "nvm" {
		if _, err := exec.LookPath(tool.BinaryName); err != nil {
			return "", fmt.Errorf("binary %s not found", tool.BinaryName)
		}
	}
	if tool.CheckCommand != "" {
		shell := "sh"
		if tool.Name == "nvm" || tool.Name == "nodejs" {
			shell = "bash"
		}
		cmd := exec.Command(shell, "-c", tool.CheckCommand)
		out, err := cmd.Output()
		if err != nil {
			return "", err
		}
		lines := strings.Split(strings.TrimSpace(string(out)), "\n")
		if len(lines) == 0 {
			return "", fmt.Errorf("tool %s check empty output", tool.Name)
		}
		return strings.TrimSpace(lines[0]), nil
	}
	return "", fmt.Errorf("tool %s not available", tool.Name)
}

// checkInstalled runs the tool's check command and returns the version string.
func (ti *ToolInstaller) checkInstalled(tool model.DeployTool) (string, error) {
	if ok, ver := ti.VerifyTool(tool); ok {
		return ver, nil
	}
	return ti.runToolCheck(tool)
}

// installTool performs the actual installation.
func (ti *ToolInstaller) installTool(tool *model.DeployTool) InstallResult {
	log.Printf("[ToolInstaller] Installing %s (method=%s)...", tool.Name, tool.InstallMethod)

	// Mark as installing
	ti.updateStatus(tool.ID, model.ToolInstalling, "", "")

	var installOut string
	var err error
	if tool.InstallScript != "" {
		installOut, err = ti.runInstallScript(tool)
	} else if tool.DownloadURL != "" {
		installOut, err = ti.downloadBinary(tool)
	} else {
		err = fmt.Errorf("no install script or download URL configured for %s", tool.Name)
	}

	if err != nil {
		errMsg := err.Error()
		if installOut != "" {
			errMsg = installOut + "\n---\n" + errMsg
		}
		log.Printf("[ToolInstaller] ERROR installing %s: %s", tool.Name, errMsg)
		ti.updateStatus(tool.ID, model.ToolFailed, "", truncateInstallLog(errMsg, 512))
		return InstallResult{Output: installOut, Err: fmt.Errorf("failed to install %s: %w", tool.Name, err)}
	}

	// 安装后验证（优先文件检测，避免 PATH/source 问题）// Logan.Li
	verifyOut := ti.captureVerifyOutput(*tool)
	if ok, ver := ti.VerifyTool(*tool); ok {
		log.Printf("[ToolInstaller] %s installed successfully: %s", tool.Name, ver)
		ti.updateStatus(tool.ID, model.ToolInstalled, ver, "")
		return InstallResult{Output: installOut, VerifyOut: verifyOut, Installed: true, Version: ver}
	}
	log.Printf("[ToolInstaller] WARNING: %s script ok but verify failed", tool.Name)
	failMsg := "安装脚本执行完成但验证未通过，请点击「测试」重新检测"
	ti.updateStatus(tool.ID, model.ToolFailed, "", failMsg)
	return InstallResult{
		Output: installOut, VerifyOut: verifyOut,
		Err: fmt.Errorf("verify failed after install %s", tool.Name),
	}
}

// captureVerifyOutput 执行验证命令并捕获输出（供审计）// Logan.Li
func (ti *ToolInstaller) captureVerifyOutput(tool model.DeployTool) string {
	if tool.CheckCommand == "" {
		return ""
	}
	shell := "sh"
	if tool.Name == "nvm" || tool.Name == "nodejs" {
		shell = "bash"
	}
	cmd := exec.Command(shell, "-c", tool.CheckCommand)
	out, err := cmd.CombinedOutput()
	text := strings.TrimSpace(string(out))
	if err != nil && text == "" {
		return err.Error()
	}
	return text
}

func truncateInstallLog(s string, n int) string {
	s = strings.TrimSpace(s)
	if len(s) > n {
		return s[:n] + "..."
	}
	return s
}

// runInstallScript executes the tool's install script in a subshell.
func (ti *ToolInstaller) runInstallScript(tool *model.DeployTool) (string, error) {
	// Write script to temp file
	tmpFile, err := os.CreateTemp("", fmt.Sprintf("tool-install-%s-*.sh", tool.Name))
	if err != nil {
		return "", fmt.Errorf("cannot create temp script: %w", err)
	}
	defer os.Remove(tmpFile.Name())

	version := tool.DefaultVersion
	if version == "" {
		version = "latest"
	}

	script := fmt.Sprintf("#!/bin/sh\nset -e\nTOOL_VERSION=%s\n%s\n", version, tool.InstallScript)
	if _, err := tmpFile.WriteString(script); err != nil {
		return "", fmt.Errorf("cannot write temp script: %w", err)
	}
	tmpFile.Close()
	os.Chmod(tmpFile.Name(), 0755)

	shell := "sh"
	if tool.Name == "nvm" || tool.Name == "nodejs" {
		shell = "bash"
	}
	cmd := exec.Command(shell, tmpFile.Name())
	var buf bytes.Buffer
	// 同时输出到容器日志便于排障 // Logan.Li
	cmd.Stdout = io.MultiWriter(os.Stdout, &buf)
	cmd.Stderr = io.MultiWriter(os.Stderr, &buf)
	err = cmd.Run()
	return buf.String(), err
}

// downloadBinary downloads a binary file to the install path.
// Uses multi-mirror fallback: tries each mirror URL in order, with HEAD verification
// to skip dead mirrors before attempting a full download.
func (ti *ToolInstaller) downloadBinary(tool *model.DeployTool) (string, error) {
	version := tool.DefaultVersion
	if version == "" {
		// Try to get latest version
		if tool.VersionURL != "" {
			v, err := ti.fetchVersion(tool.VersionURL)
			if err != nil {
				log.Printf("[ToolInstaller] WARNING: cannot fetch version for %s: %v, using default", tool.Name, err)
			} else {
				version = v
			}
		}
	}
	if version == "" {
		version = "latest"
	}

	// Resolve mirror URLs — domestic mirrors prioritized when in China
	mirrorURLs := GetMirrorsForTool(tool.Name, tool.DownloadURL)
	if len(mirrorURLs) == 0 {
		return "", fmt.Errorf("no download URLs configured for %s", tool.Name)
	}

	// Try each mirror in order
	var lastErr error
	var logBuf strings.Builder
	for i, urlTemplate := range mirrorURLs {
		url := strings.ReplaceAll(urlTemplate, "{version}", version)
		log.Printf("[ToolInstaller] Downloading %s from mirror[%d]: %s", tool.Name, i, url)
		logBuf.WriteString(fmt.Sprintf("[%d] %s\n", i, url))

		err := ti.tryDownload(url, tool)
		if err == nil {
			logBuf.WriteString(fmt.Sprintf("OK: downloaded from mirror[%d]\n", i))
			return logBuf.String(), nil
		}
		lastErr = err
		logBuf.WriteString(fmt.Sprintf("FAIL mirror[%d]: %v\n", i, err))
		log.Printf("[ToolInstaller] Mirror[%d] failed for %s: %v, trying next...", i, tool.Name, err)
	}

	return logBuf.String(), fmt.Errorf("all %d mirrors exhausted for %s, last error: %w", len(mirrorURLs), tool.Name, lastErr)
}

// tryDownload attempts a single download from a URL.
func (ti *ToolInstaller) tryDownload(url string, tool *model.DeployTool) error {
	// Use a client with timeout for the download phase.
	// Large files (kubectl ~50MB) can take minutes on slow networks.
	client := &http.Client{Timeout: 30 * time.Minute}
	resp, err := client.Get(url)
	if err != nil {
		return fmt.Errorf("download failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("download returned HTTP %d", resp.StatusCode)
	}

	// Write to temp file first, then rename (atomic-ish)
	installPath := tool.InstallPath
	if installPath == "" {
		installPath = filepath.Join("/usr/local/bin", tool.BinaryName)
	}

	dir := filepath.Dir(installPath)
	tmpFile, err := os.CreateTemp(dir, fmt.Sprintf(".%s-download-*", tool.Name))
	if err != nil {
		return fmt.Errorf("cannot create temp file: %w", err)
	}
	defer os.Remove(tmpFile.Name())

	if _, err := io.Copy(tmpFile, resp.Body); err != nil {
		tmpFile.Close()
		return fmt.Errorf("failed to save download: %w", err)
	}
	tmpFile.Close()

	os.Chmod(tmpFile.Name(), 0755)

	if err := os.Rename(tmpFile.Name(), installPath); err != nil {
		// Fallback: copy
		data, _ := os.ReadFile(tmpFile.Name())
		if writeErr := os.WriteFile(installPath, data, 0755); writeErr != nil {
			return fmt.Errorf("cannot move binary to %s: %w", installPath, writeErr)
		}
	}

	return nil
}

// fetchVersion gets the latest version string from a URL.
func (ti *ToolInstaller) fetchVersion(url string) (string, error) {
	client := &http.Client{Timeout: 15 * time.Second}
	resp, err := client.Get(url)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(io.LimitReader(resp.Body, 256))
	if err != nil {
		return "", err
	}
	return strings.TrimSpace(string(body)), nil
}

// updateStatus updates the tool's status in the database.
func (ti *ToolInstaller) updateStatus(toolID uint, status model.ToolStatus, version string, errMsg string) {
	now := time.Now()
	updates := map[string]interface{}{
		"status":    status,
		"last_check": &now,
	}
	if version != "" {
		updates["installed_ver"] = version // 与 GORM 列名一致 // Logan.Li
	}
	if errMsg != "" {
		updates["error_msg"] = errMsg
	} else if status == model.ToolInstalled {
		updates["error_msg"] = ""
	}
	ti.db.Model(&model.DeployTool{}).Where("id = ?", toolID).Updates(updates)
}

// SeedTools inserts predefined tools into the database if the table is empty.
func (ti *ToolInstaller) SeedTools() {
	var count int64
	ti.db.Model(&model.DeployTool{}).Count(&count)
	if count > 0 {
		// U4: 即使已有数据也升级工具配置（git/docker-cli 从 preinstall→lazy）
		ti.UpgradeTools()
		return
	}

	tools := model.PredefinedTools()
	now := time.Now()
	for i := range tools {
		tools[i].CreatedAt = now
		tools[i].UpdatedAt = now
		// Check if preinstalled tools are actually available
		if tools[i].InstallMethod == model.ToolPreinstall {
			if ver, err := ti.checkInstalled(tools[i]); err == nil {
				tools[i].Status = model.ToolInstalled
				tools[i].InstalledVer = ver
			} else {
				tools[i].Status = model.ToolNotInstalled
			}
		}
	}

	if err := ti.db.Create(&tools).Error; err != nil {
		log.Printf("[ToolInstaller] Seed failed: %v", err)
	} else {
		log.Printf("[ToolInstaller] Seeded %d tools", len(tools))
	}

	// U4: 新种子也执行升级
	ti.UpgradeTools()
}

// UpgradeTools updates existing tool configs to match latest predefined definitions.
// U4: git/docker-cli 从 preinstall 迁移到 lazy（镜像瘦身）。
func (ti *ToolInstaller) UpgradeTools() {
	upgrades := map[string]struct {
		installMethod  model.ToolInstallMethod
		installScript  string
		description    string
	}{
		"git": {
			installMethod: model.ToolLazy,
			installScript: "apk add --no-cache git",
			description:   "版本控制工具，流水线代码拉取使用（首次使用自动安装）",
		},
		"docker-cli": {
			installMethod: model.ToolLazy,
			installScript: "apk add --no-cache docker-cli",
			description:   "Docker 命令行工具，流水线镜像构建/推送使用（首次使用自动安装）",
		},
	}

	for name, up := range upgrades {
		var tool model.DeployTool
		if err := ti.db.Where("name = ?", name).First(&tool).Error; err != nil {
			continue // tool not in DB, skip
		}
		if tool.InstallMethod == up.installMethod && tool.InstallScript == up.installScript {
			continue // already up to date
		}
		log.Printf("[ToolInstaller] U4 upgrade: %s %s→%s", name, tool.InstallMethod, up.installMethod)
		ti.db.Model(&model.DeployTool{}).Where("name = ?", name).Updates(map[string]interface{}{
			"install_method": up.installMethod,
			"install_script": up.installScript,
			"description":    up.description,
		})
	}

	// 补全新增工具（如 golang）并校正排序 // Logan.Li
	now := time.Now()
	for _, def := range model.PredefinedTools() {
		var existing model.DeployTool
		if err := ti.db.Where("name = ?", def.Name).First(&existing).Error; err != nil {
			def.CreatedAt = now
			def.UpdatedAt = now
			def.Status = model.ToolNotInstalled
			if err := ti.db.Create(&def).Error; err != nil {
				log.Printf("[ToolInstaller] Failed to seed missing tool %s: %v", def.Name, err)
			} else {
				log.Printf("[ToolInstaller] Added missing tool: %s", def.Name)
			}
		}
	}
	sortBumps := map[string]int{"jdk": 1, "maven": 2, "golang": 3, "nvm": 4, "nodejs": 5, "git": 6, "docker-cli": 7}
	for name, order := range sortBumps {
		ti.db.Model(&model.DeployTool{}).Where("name = ?", name).Update("sort_order", order)
	}

	// 同步 JDK/Maven/Go/NVM 安装脚本与检测命令修复 // Logan.Li
	type toolPatch struct {
		script string
		check  string
	}
	patchSync := map[string]toolPatch{}
	for _, t := range model.PredefinedTools() {
		if t.Name == "jdk" || t.Name == "maven" || t.Name == "golang" || t.Name == "nvm" || t.Name == "nodejs" {
			patchSync[t.Name] = toolPatch{script: t.InstallScript, check: t.CheckCommand}
		}
	}
	for name, p := range patchSync {
		updates := map[string]interface{}{
			"install_script": p.script,
			"check_command":  p.check,
		}
		if name == "nodejs" {
			updates["default_version"] = "lts"
		}
		if name == "golang" {
			updates["default_version"] = "1.24.0"
		}
		ti.db.Model(&model.DeployTool{}).Where("name = ?", name).Updates(updates)
	}
}