// Package api 管理 API（/api/v1）：认证、用户、密钥、用量、管理后台。
package api

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

	"github.com/gin-gonic/gin"
	"github.com/openteam/server/internal/api/middleware"
	"github.com/openteam/server/internal/app"
	"github.com/openteam/server/internal/passkey"
	"github.com/openteam/server/internal/pkg/resp"
	"github.com/openteam/server/internal/proxy"
	"github.com/openteam/server/internal/store"
)

// Handler 聚合所有管理 API。
type Handler struct {
	a        *app.App
	gw       *proxy.Gateway
	passkeys *passkey.Service
}

func NewHandler(a *app.App, gw *proxy.Gateway, pk *passkey.Service) *Handler {
	return &Handler{a: a, gw: gw, passkeys: pk}
}

// ---------------------------------------------------------------------------
// 认证

type registerReq struct {
	Username   string `json:"username" binding:"required,min=3,max=32"`
	Email      string `json:"email" binding:"required,email"`
	Password   string `json:"password" binding:"required,min=8,max=72"`
	InviteCode string `json:"invite_code"`
}

// Register POST /api/v1/auth/register
func (h *Handler) Register(c *gin.Context) {
	var req registerReq
	if err := c.ShouldBindJSON(&req); err != nil {
		resp.Fail(c, http.StatusBadRequest, "invalid input: "+err.Error())
		return
	}
	// 注册模式优先读系统配置（管理后台可改），缺省用环境配置
	mode := h.a.Cfg.Auth.RegistrationMode
	var modeCfgRaw string
	h.a.DB.Model(&store.SystemConfig{}).Where("key = ?", "registration_mode").Pluck("value", &modeCfgRaw)
	var modeCfg string
	_ = json.Unmarshal([]byte(modeCfgRaw), &modeCfg)
	if modeCfg == "open" || modeCfg == "invite" {
		mode = modeCfg
	}
	if mode == "invite" {
		var icRaw string
		h.a.DB.Model(&store.SystemConfig{}).Where("key = ?", "invite_codes").Pluck("value", &icRaw)
		var ic string
		_ = json.Unmarshal([]byte(icRaw), &ic)
		if req.InviteCode == "" || !strings.Contains(ic, req.InviteCode) {
			resp.Fail(c, http.StatusForbidden, "valid invite code required")
			return
		}
	}
	var count int64
	h.a.DB.Model(&store.User{}).Where("username = ? OR email = ?", req.Username, req.Email).Count(&count)
	if count > 0 {
		resp.Fail(c, http.StatusConflict, "username or email already exists")
		return
	}
	hash, err := h.a.Hasher.HashPassword(req.Password)
	if err != nil {
		resp.Fail(c, http.StatusInternalServerError, "failed to hash password")
		return
	}
	u := store.User{
		Username:     req.Username,
		Email:        strings.ToLower(req.Email),
		PasswordHash: hash,
		Role:         store.RoleUser,
		Balance:      5.0, // 新用户赠送体验余额（可通过 admin 调整）
		Status:       store.UserStatusActive,
	}
	if req.InviteCode != "" {
		ic := req.InviteCode
		u.InviteCode = &ic
	}
	if err := h.a.DB.Create(&u).Error; err != nil {
		resp.Fail(c, http.StatusInternalServerError, "failed to create user")
		return
	}
	resp.Created(c, gin.H{"id": u.ID, "username": u.Username})
}

type loginReq struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

// Login POST /api/v1/auth/login — 返回 access token，refresh token 写入 HttpOnly Cookie。
func (h *Handler) Login(c *gin.Context) {
	var req loginReq
	if err := c.ShouldBindJSON(&req); err != nil {
		resp.Fail(c, http.StatusBadRequest, "invalid input")
		return
	}
	var u store.User
	err := h.a.DB.Where("username = ? OR email = ?", req.Username, strings.ToLower(req.Username)).First(&u).Error
	if err != nil || u.Status != store.UserStatusActive {
		resp.Fail(c, http.StatusUnauthorized, "invalid credentials")
		return
	}
	ok, err := h.a.Hasher.VerifyPassword(u.PasswordHash, req.Password)
	if err != nil || !ok {
		resp.Fail(c, http.StatusUnauthorized, "invalid credentials")
		return
	}
	now := time.Now()
	h.a.DB.Model(&u).Update("last_login_at", now)

	access, _, err := h.a.JWT.Sign(u.ID, u.Username, u.Role, "access")
	if err != nil {
		resp.Fail(c, http.StatusInternalServerError, "failed to issue token")
		return
	}
	refresh, _, err := h.a.JWT.Sign(u.ID, u.Username, u.Role, "refresh")
	if err != nil {
		resp.Fail(c, http.StatusInternalServerError, "failed to issue token")
		return
	}
	h.setRefreshCookie(c, refresh)
	resp.OK(c, gin.H{"access_token": access, "expires_in": int(h.a.JWT.AccessTTL().Seconds()), "user": h.publicUser(&u)})
}

// Refresh POST /api/v1/auth/refresh — 用 refresh cookie 换新 access token。
func (h *Handler) Refresh(c *gin.Context) {
	tok, err := c.Cookie(h.a.Cfg.JWT.CookieName)
	if err != nil || tok == "" {
		resp.Fail(c, http.StatusUnauthorized, "refresh token missing")
		return
	}
	claims, err := h.a.JWT.Parse(tok)
	if err != nil || claims.Subject != "refresh" {
		resp.Fail(c, http.StatusUnauthorized, "invalid refresh token")
		return
	}
	var u store.User
	if err := h.a.DB.First(&u, claims.UserID).Error; err != nil || u.Status != store.UserStatusActive {
		resp.Fail(c, http.StatusUnauthorized, "user not found or disabled")
		return
	}
	access, _, err := h.a.JWT.Sign(u.ID, u.Username, u.Role, "access")
	if err != nil {
		resp.Fail(c, http.StatusInternalServerError, "failed to issue token")
		return
	}
	resp.OK(c, gin.H{"access_token": access, "expires_in": int(h.a.JWT.AccessTTL().Seconds())})
}

// Logout POST /api/v1/auth/logout — 清除 refresh cookie。
func (h *Handler) Logout(c *gin.Context) {
	h.setRefreshCookie(c, "")
	resp.OK(c, gin.H{"ok": true})
}

type changePasswordReq struct {
	OldPassword string `json:"old_password" binding:"required"`
	NewPassword string `json:"new_password" binding:"required,min=8,max=72"`
}

// ChangePassword POST /api/v1/auth/password — 修改密码。
func (h *Handler) ChangePassword(c *gin.Context) {
	u := sessionUser(c)
	var req changePasswordReq
	if err := c.ShouldBindJSON(&req); err != nil {
		resp.Fail(c, http.StatusBadRequest, "invalid input: "+err.Error())
		return
	}
	ok, err := h.a.Hasher.VerifyPassword(u.PasswordHash, req.OldPassword)
	if err != nil || !ok {
		resp.Fail(c, http.StatusBadRequest, "旧密码不正确")
		return
	}
	hash, err := h.a.Hasher.HashPassword(req.NewPassword)
	if err != nil {
		resp.Fail(c, http.StatusInternalServerError, "failed to hash password")
		return
	}
	if err := h.a.DB.Model(&store.User{}).Where("id = ?", u.ID).Update("password_hash", hash).Error; err != nil {
		resp.Fail(c, http.StatusInternalServerError, "failed to update password")
		return
	}
	resp.OK(c, gin.H{"ok": true})
}

// Me GET /api/v1/auth/me
func (h *Handler) Me(c *gin.Context) {
	u := sessionUser(c)
	resp.OK(c, gin.H{"user": h.publicUser(u)})
}

func (h *Handler) setRefreshCookie(c *gin.Context, value string) {
	maxAge := int(h.a.JWT.RefreshTTL().Seconds())
	if value == "" {
		maxAge = -1
	}
	http.SetCookie(c.Writer, &http.Cookie{
		Name:     h.a.Cfg.JWT.CookieName,
		Value:    value,
		Path:     "/",
		MaxAge:   maxAge,
		HttpOnly: true,
		Secure:   h.a.Cfg.JWT.CookieSecure,
		SameSite: http.SameSiteLaxMode,
		Domain:   h.a.Cfg.JWT.CookieDomain,
	})
}

func (h *Handler) publicUser(u *store.User) gin.H {
	return gin.H{
		"id":         u.ID,
		"username":   u.Username,
		"email":      u.Email,
		"role":       u.Role,
		"balance":    u.Balance,
		"status":     u.Status,
		"allowed_models": u.AllowedModels,
		"denied_models":  u.DeniedModels,
		"created_at": u.CreatedAt,
	}
}

func sessionUser(c *gin.Context) *store.User {
	u, _ := c.Get(middleware.CtxSessionUser)
	return u.(*store.User)
}

func userFromContext(c *gin.Context) (*store.User, bool) {
	u, ok := c.Get(middleware.CtxSessionUser)
	if !ok {
		return nil, false
	}
	return u.(*store.User), true
}