package handler

import (
	"context"
	"encoding/json"
	"net/http"
	"time"

	"github.com/enterprise-ai-platform/server/internal/middleware"
	"github.com/enterprise-ai-platform/server/internal/response"
	"github.com/enterprise-ai-platform/server/pkg/auth"
	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgxpool"
)

type AuthHandler struct {
	pool   *pgxpool.Pool
	jwtMgr *auth.JWTManager
}

func NewAuthHandler(pool *pgxpool.Pool, jwtMgr *auth.JWTManager) *AuthHandler {
	return &AuthHandler{pool: pool, jwtMgr: jwtMgr}
}

type loginRequest struct {
	Email    string `json:"email"`
	Password string `json:"password"`
	OrgID    string `json:"org_id"`
}

type orgInfo struct {
	ID        string `json:"id"`
	Name      string `json:"name"`
	Slug      string `json:"slug"`
	ShortName string `json:"short_name"`
}

type userResponse struct {
	ID         string   `json:"id"`
	Name       string   `json:"name"`
	Email      string   `json:"email"`
	AvatarURL  *string  `json:"avatar_url"`
	Role       string   `json:"role"`
	EmployeeID *string  `json:"employee_id"`
	OrgID      *string  `json:"org_id"`
	Org        *orgInfo `json:"org,omitempty"`
}

type registerRequest struct {
	Name     string `json:"name"`
	Email    string `json:"email"`
	Password string `json:"password"`
}

func (h *AuthHandler) Register(w http.ResponseWriter, r *http.Request) {
	var req registerRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		response.BadRequest(w, "无效的请求格式")
		return
	}
	if req.Name == "" || req.Email == "" || req.Password == "" {
		response.BadRequest(w, "姓名、邮箱和密码不能为空")
		return
	}
	if len(req.Password) < 6 {
		response.BadRequest(w, "密码长度不能少于6位")
		return
	}

	var exists bool
	h.pool.QueryRow(r.Context(), `SELECT EXISTS(SELECT 1 FROM users WHERE email = $1)`, req.Email).Scan(&exists)
	if exists {
		response.Error(w, http.StatusConflict, 40901, "该邮箱已注册")
		return
	}

	hash, err := auth.HashPassword(req.Password)
	if err != nil {
		response.InternalError(w, "密码加密失败")
		return
	}

	id := uuid.New()
	_, err = h.pool.Exec(r.Context(),
		`INSERT INTO users (id, name, email, password_hash, role, status) VALUES ($1, $2, $3, $4, 'user', 'active')`,
		id, req.Name, req.Email, hash)
	if err != nil {
		response.InternalError(w, "注册失败")
		return
	}

	tokenPair, err := h.jwtMgr.GenerateTokenPair(id, req.Email, "user")
	if err != nil {
		response.InternalError(w, "生成Token失败")
		return
	}

	http.SetCookie(w, &http.Cookie{
		Name:     "access_token",
		Value:    tokenPair.AccessToken,
		Path:     "/",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		MaxAge:   int(24 * time.Hour / time.Second),
	})

	response.JSON(w, http.StatusCreated, map[string]any{
		"user": userResponse{
			ID: id.String(), Name: req.Name, Email: req.Email, Role: "user",
		},
		"access_token": tokenPair.AccessToken,
		"expires_at":   tokenPair.ExpiresAt,
	})
}

func (h *AuthHandler) Login(w http.ResponseWriter, r *http.Request) {
	var req loginRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		response.BadRequest(w, "无效的请求格式")
		return
	}

	if req.Email == "" || req.Password == "" {
		response.BadRequest(w, "邮箱和密码不能为空")
		return
	}

	var (
		id           string
		name         string
		email        string
		passwordHash *string
		avatarURL    *string
		role         string
		employeeID   *string
		status       string
		orgID        *string
	)

	err := h.pool.QueryRow(r.Context(),
		`SELECT id, name, email, password_hash, avatar_url, role, employee_id, status, org_id::text
		 FROM users WHERE email = $1`, req.Email,
	).Scan(&id, &name, &email, &passwordHash, &avatarURL, &role, &employeeID, &status, &orgID)

	if err != nil {
		response.Unauthorized(w, "邮箱或密码错误")
		return
	}

	if status != "active" {
		response.Error(w, http.StatusForbidden, 40302, "账号已被禁用")
		return
	}

	if passwordHash == nil || !auth.CheckPassword(req.Password, *passwordHash) {
		response.Unauthorized(w, "邮箱或密码错误")
		return
	}

	// 平台管理员不绑定机构，可登录任意机构入口
	// 普通用户/机构管理员必须属于所选机构
	if role != "super_admin" && req.OrgID != "" && orgID != nil && *orgID != req.OrgID {
		response.Unauthorized(w, "该账号不属于所选机构，请选择正确的机构")
		return
	}

	uid, _ := uuid.Parse(id)
	tokenPair, err := h.jwtMgr.GenerateTokenPair(uid, email, role)
	if err != nil {
		response.InternalError(w, "生成Token失败")
		return
	}

	// Update login info
	go func() {
		_, _ = h.pool.Exec(context.Background(),
			`UPDATE users SET last_login_at = NOW(), login_count = login_count + 1 WHERE id = $1`, id)
	}()

	// Set cookies
	http.SetCookie(w, &http.Cookie{
		Name:     "access_token",
		Value:    tokenPair.AccessToken,
		Path:     "/",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		MaxAge:   int(24 * time.Hour / time.Second),
	})
	http.SetCookie(w, &http.Cookie{
		Name:     "refresh_token",
		Value:    tokenPair.RefreshToken,
		Path:     "/api/v1/auth/refresh",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		MaxAge:   int(7 * 24 * time.Hour / time.Second),
	})

	usr := userResponse{
		ID: id, Name: name, Email: email,
		AvatarURL: avatarURL, Role: role, EmployeeID: employeeID,
		OrgID: orgID,
	}
	if orgID != nil {
		usr.Org = h.loadOrgInfo(r.Context(), *orgID)
	}

	response.JSON(w, http.StatusOK, map[string]any{
		"user":         usr,
		"access_token": tokenPair.AccessToken,
		"expires_at":   tokenPair.ExpiresAt,
	})
}

func (h *AuthHandler) Logout(w http.ResponseWriter, r *http.Request) {
	http.SetCookie(w, &http.Cookie{
		Name:     "access_token",
		Value:    "",
		Path:     "/",
		HttpOnly: true,
		MaxAge:   -1,
	})
	http.SetCookie(w, &http.Cookie{
		Name:     "refresh_token",
		Value:    "",
		Path:     "/api/v1/auth/refresh",
		HttpOnly: true,
		MaxAge:   -1,
	})
	response.JSON(w, http.StatusOK, nil)
}

func (h *AuthHandler) Me(w http.ResponseWriter, r *http.Request) {
	userID := middleware.GetUserID(r.Context())

	var u userResponse
	err := h.pool.QueryRow(r.Context(),
		`SELECT id, name, email, avatar_url, role, employee_id, org_id::text
		 FROM users WHERE id = $1`, userID,
	).Scan(&u.ID, &u.Name, &u.Email, &u.AvatarURL, &u.Role, &u.EmployeeID, &u.OrgID)

	if err != nil {
		response.NotFound(w, "用户不存在")
		return
	}

	if u.OrgID != nil {
		u.Org = h.loadOrgInfo(r.Context(), *u.OrgID)
	}

	response.JSON(w, http.StatusOK, u)
}

// ListOrganizations 返回所有可用机构列表
func (h *AuthHandler) ListOrganizations(w http.ResponseWriter, r *http.Request) {
	rows, err := h.pool.Query(r.Context(),
		`SELECT id, name, slug, COALESCE(short_name,''), COALESCE(description,''), COALESCE(logo_url,'')
		 FROM organizations WHERE is_active = true ORDER BY sort_order ASC`)
	if err != nil {
		response.InternalError(w, "查询机构列表失败")
		return
	}
	defer rows.Close()

	var orgs []map[string]any
	for rows.Next() {
		var id, name, slug, shortName, desc, logo string
		if rows.Scan(&id, &name, &slug, &shortName, &desc, &logo) != nil {
			continue
		}
		orgs = append(orgs, map[string]any{
			"id": id, "name": name, "slug": slug,
			"short_name": shortName, "description": desc, "logo_url": logo,
		})
	}
	if orgs == nil {
		orgs = []map[string]any{}
	}
	response.JSON(w, http.StatusOK, orgs)
}

// SwitchOrg 切换机构：管理员及以上可用，自动切换为目标机构的管理员身份
func (h *AuthHandler) SwitchOrg(w http.ResponseWriter, r *http.Request) {
	currentRole := middleware.GetRole(r.Context())
	if currentRole != "super_admin" && currentRole != "admin" {
		response.Forbidden(w, "仅管理员可以切换机构")
		return
	}

	var req struct {
		OrgID string `json:"org_id"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.OrgID == "" {
		response.BadRequest(w, "请选择机构")
		return
	}

	// 校验机构是否存在
	var exists bool
	h.pool.QueryRow(r.Context(),
		`SELECT EXISTS(SELECT 1 FROM organizations WHERE id = $1 AND is_active = true)`, req.OrgID).Scan(&exists)
	if !exists {
		response.NotFound(w, "机构不存在")
		return
	}

	// 查找目标机构的管理员用户（优先admin，其次super_admin，最后creator）
	var targetID uuid.UUID
	var targetEmail, targetRole, targetName string
	err := h.pool.QueryRow(r.Context(),
		`SELECT id, email, role, name FROM users
		 WHERE org_id = $1 AND status = 'active'
		 ORDER BY CASE role WHEN 'admin' THEN 1 WHEN 'super_admin' THEN 2 WHEN 'creator' THEN 3 ELSE 4 END
		 LIMIT 1`, req.OrgID).Scan(&targetID, &targetEmail, &targetRole, &targetName)
	if err != nil {
		response.InternalError(w, "该机构暂无可用用户")
		return
	}

	// 为目标用户生成新的JWT token
	tokens, err := h.jwtMgr.GenerateTokenPair(targetID, targetEmail, targetRole)
	if err != nil {
		response.InternalError(w, "生成令牌失败")
		return
	}

	org := h.loadOrgInfo(r.Context(), req.OrgID)
	response.JSON(w, http.StatusOK, map[string]any{
		"message": "已切换",
		"org":     org,
		"token":   tokens.AccessToken,
		"user": map[string]any{
			"id":     targetID,
			"name":   targetName,
			"email":  targetEmail,
			"role":   targetRole,
			"org_id": req.OrgID,
		},
	})
}

func (h *AuthHandler) loadOrgInfo(ctx context.Context, orgID string) *orgInfo {
	var o orgInfo
	err := h.pool.QueryRow(ctx,
		`SELECT id, name, slug, COALESCE(short_name,'') FROM organizations WHERE id = $1`, orgID,
	).Scan(&o.ID, &o.Name, &o.Slug, &o.ShortName)
	if err != nil {
		return nil
	}
	return &o
}

func (h *AuthHandler) UpdateProfile(w http.ResponseWriter, r *http.Request) {
	userID := middleware.GetUserID(r.Context())

	var req struct {
		Name      string `json:"name"`
		AvatarURL string `json:"avatar_url"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		response.BadRequest(w, "无效的请求格式")
		return
	}

	_, err := h.pool.Exec(r.Context(),
		`UPDATE users SET name = COALESCE(NULLIF($2,''), name),
		 avatar_url = COALESCE(NULLIF($3,''), avatar_url),
		 updated_at = NOW()
		 WHERE id = $1`, userID, req.Name, req.AvatarURL)
	if err != nil {
		response.InternalError(w, "更新个人信息失败")
		return
	}
	response.JSON(w, http.StatusOK, map[string]string{"message": "已更新"})
}

func (h *AuthHandler) Refresh(w http.ResponseWriter, r *http.Request) {
	cookie, err := r.Cookie("refresh_token")
	if err != nil {
		response.Unauthorized(w, "Refresh Token 不存在")
		return
	}

	claims, err := h.jwtMgr.ValidateToken(cookie.Value)
	if err != nil {
		response.Error(w, http.StatusUnauthorized, 40102, "Refresh Token 已过期")
		return
	}

	// Get current role from DB
	var role string
	err = h.pool.QueryRow(r.Context(),
		`SELECT role FROM users WHERE id = $1 AND status = 'active'`, claims.UserID,
	).Scan(&role)
	if err != nil {
		response.Unauthorized(w, "用户不存在或已被禁用")
		return
	}

	tokenPair, err := h.jwtMgr.GenerateTokenPair(claims.UserID, claims.Email, role)
	if err != nil {
		response.InternalError(w, "生成Token失败")
		return
	}

	http.SetCookie(w, &http.Cookie{
		Name:     "access_token",
		Value:    tokenPair.AccessToken,
		Path:     "/",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		MaxAge:   int(24 * time.Hour / time.Second),
	})

	response.JSON(w, http.StatusOK, map[string]any{
		"access_token": tokenPair.AccessToken,
		"expires_at":   tokenPair.ExpiresAt,
	})
}