package handler

import (
	"context"
	"fmt"
	"io"
	"mime/multipart"
	"os"
	"path"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"spider/internal/model"
	"spider/internal/store"
	"spider/internal/telegram"
	"spider/internal/telegram/sessionimport"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
)

// TgAccountHandler handles Telegram account management.
type TgAccountHandler struct {
	store       *store.Store
	tgManager   *telegram.AccountManager
	crypto      *telegram.Crypto
	sessionsDir string
	tmpDir      string // <sessionsDir>/.tmp — staging area for multipart uploads
}

// NewTgAccountHandler builds the handler with dependencies injected from main.
func NewTgAccountHandler(s *store.Store, tgMgr *telegram.AccountManager, crypto *telegram.Crypto, sessionsDir string) *TgAccountHandler {
	tmp := filepath.Join(sessionsDir, ".tmp")
	_ = os.MkdirAll(tmp, 0o755)
	h := &TgAccountHandler{
		store:       s,
		tgManager:   tgMgr,
		crypto:      crypto,
		sessionsDir: sessionsDir,
		tmpDir:      tmp,
	}
	go h.tmpCleanupLoop()
	return h
}

// tmpCleanupLoop deletes tmp subdirs older than 30 minutes every 10 minutes.
func (h *TgAccountHandler) tmpCleanupLoop() {
	t := time.NewTicker(10 * time.Minute)
	defer t.Stop()
	for range t.C {
		entries, err := os.ReadDir(h.tmpDir)
		if err != nil {
			continue
		}
		cutoff := time.Now().Add(-30 * time.Minute)
		for _, e := range entries {
			if !e.IsDir() {
				continue
			}
			info, err := e.Info()
			if err != nil || info.ModTime().After(cutoff) {
				continue
			}
			_ = os.RemoveAll(filepath.Join(h.tmpDir, e.Name()))
		}
	}
}

// List handles GET /tg-accounts
func (h *TgAccountHandler) List(c *gin.Context) {
	var accounts []model.TgAccount
	h.store.DB.Order("id ASC").Find(&accounts)

	// Enrich with live status from account manager
	statuses := h.tgManager.GetStatuses()
	for i := range accounts {
		if s, ok := statuses[accounts[i].Phone]; ok {
			accounts[i].Status = s
		}
	}

	OK(c, accounts)
}

// Create handles POST /tg-accounts
func (h *TgAccountHandler) Create(c *gin.Context) {
	var req struct {
		Phone       string `json:"phone" binding:"required"`
		SessionFile string `json:"session_file" binding:"required"`
		AppID       int    `json:"app_id" binding:"required"`
		AppHash     string `json:"app_hash" binding:"required"`
		Remark      string `json:"remark"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		Fail(c, 400, err.Error())
		return
	}

	// Check duplicate
	var count int64
	h.store.DB.Model(&model.TgAccount{}).Where("phone = ?", req.Phone).Count(&count)
	if count > 0 {
		Fail(c, 409, "该手机号已存在")
		return
	}

	acc := model.TgAccount{
		Phone:       req.Phone,
		SessionFile: req.SessionFile,
		AppID:       req.AppID,
		AppHash:     req.AppHash,
		Remark:      req.Remark,
		Enabled:     true,
		Status:      "idle",
	}
	if err := h.store.DB.Create(&acc).Error; err != nil {
		Fail(c, 500, err.Error())
		return
	}

	// Reload account manager
	h.reloadAccounts()

	LogAudit(h.store, c, "create", "tg_account", fmt.Sprintf("%d", acc.ID), gin.H{"phone": acc.Phone})
	OK(c, acc)
}

// Update handles PUT /tg-accounts/:id
func (h *TgAccountHandler) Update(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		Fail(c, 400, "invalid id")
		return
	}

	var acc model.TgAccount
	if err := h.store.DB.First(&acc, id).Error; err != nil {
		Fail(c, 404, "账号不存在")
		return
	}

	var req struct {
		SessionFile *string `json:"session_file"`
		AppID       *int    `json:"app_id"`
		AppHash     *string `json:"app_hash"`
		Remark      *string `json:"remark"`
		Enabled     *bool   `json:"enabled"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		Fail(c, 400, err.Error())
		return
	}

	updates := map[string]any{}
	if req.SessionFile != nil {
		updates["session_file"] = *req.SessionFile
	}
	if req.AppID != nil {
		updates["app_id"] = *req.AppID
	}
	if req.AppHash != nil {
		updates["app_hash"] = *req.AppHash
	}
	if req.Remark != nil {
		updates["remark"] = *req.Remark
	}
	if req.Enabled != nil {
		updates["enabled"] = *req.Enabled
	}

	h.store.DB.Model(&acc).Updates(updates)
	h.store.DB.First(&acc, id)

	h.reloadAccounts()

	LogAudit(h.store, c, "update", "tg_account", fmt.Sprintf("%d", id), updates)
	OK(c, acc)
}

// Delete handles DELETE /tg-accounts/:id
func (h *TgAccountHandler) Delete(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		Fail(c, 400, "invalid id")
		return
	}

	if err := h.store.DB.Delete(&model.TgAccount{}, id).Error; err != nil {
		Fail(c, 500, err.Error())
		return
	}

	h.reloadAccounts()

	LogAudit(h.store, c, "delete", "tg_account", fmt.Sprintf("%d", id), nil)
	OK(c, gin.H{"message": "已删除"})
}

// Test handles POST /tg-accounts/:id/test — tests if the account can connect.
func (h *TgAccountHandler) Test(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		Fail(c, 400, "invalid id")
		return
	}

	var acc model.TgAccount
	if err := h.store.DB.First(&acc, id).Error; err != nil {
		Fail(c, 404, "账号不存在")
		return
	}

	client := telegram.New(telegram.Account{
		Phone:       acc.Phone,
		SessionFile: acc.SessionFile,
		AppID:       acc.AppID,
		AppHash:     acc.AppHash,
	})

	ctx, cancel := context.WithTimeout(c.Request.Context(), 30*time.Second)
	defer cancel()

	if err := client.Connect(ctx); err != nil {
		if fwe, ok := err.(*telegram.FloodWaitError); ok {
			OK(c, gin.H{"status": "cooling", "message": fmt.Sprintf("FloodWait: 需等待 %d 秒", fwe.Seconds)})
			return
		}
		OK(c, gin.H{"status": "fail", "error": err.Error()})
		return
	}
	client.Disconnect()

	OK(c, gin.H{"status": "ok", "message": "连接成功"})
}

// Import handles POST /tg-accounts/import — admin uploads a 协议号 folder.
func (h *TgAccountHandler) Import(c *gin.Context) {
	form, err := c.MultipartForm()
	if err != nil {
		Fail(c, 400, "invalid multipart form: "+err.Error())
		return
	}

	files := form.File["files"]
	if len(files) == 0 {
		Fail(c, 400, "no files uploaded (expected field name: files)")
		return
	}

	// Stage uploaded files to tmp/<uuid>/.
	stageID := uuid.NewString()
	stageDir := filepath.Join(h.tmpDir, stageID)
	if err := os.MkdirAll(stageDir, 0o755); err != nil {
		Fail(c, 500, "create stage dir: "+err.Error())
		return
	}

	// Top-level folder name in webkitRelativePath (e.g. "13252753163"). Used to
	// strip the prefix so RelPath inside the Result is relative to the folder.
	topPrefix := detectTopPrefix(files)

	staged := make([]sessionimport.StagedFile, 0, len(files))
	for _, fh := range files {
		// Gin stores the relative path in fh.Filename (browsers send it as the
		// form part filename when webkitdirectory is used).
		rel := normalizeRel(fh.Filename, topPrefix)
		if rel == "" {
			continue
		}
		abs := filepath.Join(stageDir, rel)
		if err := os.MkdirAll(filepath.Dir(abs), 0o755); err != nil {
			Fail(c, 500, "mkdir stage: "+err.Error())
			return
		}
		if err := saveUpload(fh, abs); err != nil {
			Fail(c, 500, "save upload: "+err.Error())
			return
		}
		staged = append(staged, sessionimport.StagedFile{RelPath: rel, AbsPath: abs})
	}

	ctx, cancel := context.WithTimeout(c.Request.Context(), 60*time.Second)
	defer cancel()

	res, err := sessionimport.Import(ctx, h.sessionsDir, staged)
	if err != nil {
		detail := gin.H{"error": err.Error()}
		if res != nil {
			detail["pyrogram_err"] = res.PyrogramErr
			detail["tdata_err"] = res.TdataErr
			detail["tmp_dir"] = stageDir
		}
		c.JSON(422, gin.H{
			"code":    422,
			"message": err.Error(),
			"data":    detail,
		})
		return
	}

	cleanupOnFail := func() {
		if res != nil {
			if res.SessionFile != "" {
				_ = os.Remove(res.SessionFile)
			}
			if res.OriginDir != "" {
				_ = os.RemoveAll(res.OriginDir)
			}
		}
	}

	// Duplicate check.
	var count int64
	h.store.DB.Model(&model.TgAccount{}).Where("phone = ?", res.Meta.Phone).Count(&count)
	if count > 0 {
		cleanupOnFail()
		Fail(c, 409, "该手机号已存在")
		return
	}

	// Encrypt 2FA if present.
	var twoFAEnc []byte
	if res.TwoFAPlaintext != "" && h.crypto != nil {
		twoFAEnc, err = h.crypto.Encrypt(res.TwoFAPlaintext)
		if err != nil {
			cleanupOnFail()
			Fail(c, 500, "encrypt 2fa: "+err.Error())
			return
		}
	}

	acc := model.TgAccount{
		Phone:          res.Meta.Phone,
		SessionFile:    res.SessionFile,
		AppID:          res.Meta.APIID,
		AppHash:        res.Meta.APIHash,
		Enabled:        true,
		Status:         "idle",
		TwoFAEnc:       twoFAEnc,
		Device:         res.Meta.Device,
		AppVersion:     res.Meta.AppVersion,
		SDK:            res.Meta.SDK,
		LangPack:       res.Meta.LangPack,
		LangCode:       res.Meta.LangCode,
		SystemLangCode: res.Meta.SystemLangCode,
		FirstName:      res.Meta.FirstName,
		LastName:       res.Meta.LastName,
		TgUsername:     res.Meta.Username,
		OriginDir:      res.OriginDir,
		ImportStatus:   "ok",
		Source:         "protocol",
	}
	if err := h.store.DB.Create(&acc).Error; err != nil {
		if strings.Contains(strings.ToLower(err.Error()), "duplicate") {
			cleanupOnFail()
			Fail(c, 409, "该手机号已存在")
			return
		}
		cleanupOnFail()
		Fail(c, 500, "db create: "+err.Error())
		return
	}

	// Rebuild account manager so new account is Acquireable.
	h.reloadAccounts()

	// Auto-test — detach from the HTTP request context so a client disconnect
	// cannot falsely mark a freshly imported account as dead.
	bgCtx, bgCancel := context.WithTimeout(context.Background(), 45*time.Second)
	defer bgCancel()
	testResult := h.runTest(bgCtx, &acc)
	if testResult["status"] == "fail" {
		h.store.DB.Model(&acc).Updates(map[string]any{
			"enabled":       false,
			"import_status": "dead",
		})
	}

	LogAudit(h.store, c, "import", "tg_account", fmt.Sprintf("%d", acc.ID), gin.H{
		"phone":  acc.Phone,
		"source": res.UsedSource,
	})

	// Reload original so JSON response reflects updates.
	h.store.DB.First(&acc, acc.ID)

	// Cleanup stage dir on success.
	_ = os.RemoveAll(stageDir)

	OK(c, gin.H{"account": acc, "test_result": testResult})
}

// runTest calls Client.Connect + waits for ready — no GetMe, kept minimal.
func (h *TgAccountHandler) runTest(ctx context.Context, acc *model.TgAccount) gin.H {
	client := telegram.New(telegram.Account{
		Phone:          acc.Phone,
		SessionFile:    acc.SessionFile,
		AppID:          acc.AppID,
		AppHash:        acc.AppHash,
		Device:         acc.Device,
		AppVersion:     acc.AppVersion,
		SystemVersion:  acc.SDK,
		LangPack:       acc.LangPack,
		LangCode:       acc.LangCode,
		SystemLangCode: acc.SystemLangCode,
	})
	tctx, cancel := context.WithTimeout(ctx, 30*time.Second)
	defer cancel()
	if err := client.Connect(tctx); err != nil {
		if fwe, ok := err.(*telegram.FloodWaitError); ok {
			return gin.H{"status": "cooling", "message": fmt.Sprintf("FloodWait: 需等待 %d 秒", fwe.Seconds)}
		}
		return gin.H{"status": "fail", "error": err.Error()}
	}
	client.Disconnect()
	return gin.H{"status": "ok", "message": "连接成功"}
}

func detectTopPrefix(files []*multipart.FileHeader) string {
	if len(files) == 0 {
		return ""
	}
	first := files[0].Filename
	idx := strings.IndexAny(first, "/\\")
	if idx <= 0 {
		return ""
	}
	return first[:idx]
}

func normalizeRel(filename, topPrefix string) string {
	// Convert backslashes to forward slashes for consistent path handling.
	p := strings.ReplaceAll(filename, "\\", "/")
	// Strip the top-level directory name so e.g. "13252753163/tdata/key_datas"
	// becomes "tdata/key_datas".
	if topPrefix != "" && strings.HasPrefix(p, topPrefix+"/") {
		p = strings.TrimPrefix(p, topPrefix+"/")
	}
	// Use path.Clean (forward-slash aware) to resolve . and .. components,
	// then reject any result that escapes the staging root.
	cleaned := path.Clean(p)
	if cleaned == "." || cleaned == ".." {
		return ""
	}
	if strings.HasPrefix(cleaned, "../") {
		return ""
	}
	if filepath.IsAbs(cleaned) || strings.HasPrefix(cleaned, "/") {
		return ""
	}
	return cleaned
}

func saveUpload(fh *multipart.FileHeader, dst string) error {
	src, err := fh.Open()
	if err != nil {
		return err
	}
	defer src.Close()
	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()
	_, err = io.Copy(out, src)
	return err
}

// reloadAccounts loads enabled TG accounts from DB and reinitializes the account manager.
func (h *TgAccountHandler) reloadAccounts() {
	var dbAccounts []model.TgAccount
	h.store.DB.Where("enabled = ?", true).Find(&dbAccounts)

	accounts := make([]telegram.Account, 0, len(dbAccounts))
	for _, a := range dbAccounts {
		accounts = append(accounts, telegram.Account{
			Phone:          a.Phone,
			SessionFile:    a.SessionFile,
			AppID:          a.AppID,
			AppHash:        a.AppHash,
			Device:         a.Device,
			AppVersion:     a.AppVersion,
			SystemVersion:  a.SDK,
			LangPack:       a.LangPack,
			LangCode:       a.LangCode,
			SystemLangCode: a.SystemLangCode,
		})
	}
	h.tgManager.Init(accounts)
}