package handler

import (
	"net/http"

	"github.com/agentmail/gateway/internal/middleware"
	"github.com/agentmail/gateway/internal/models"
	"github.com/agentmail/gateway/internal/repo"
	"github.com/agentmail/gateway/internal/sse"
	"github.com/google/uuid"
)

// ---------- Contacts（左侧联系人界面，按登录用户隔离） ----------

// GET /api/v1/contacts?archived=false
func ListContacts(w http.ResponseWriter, r *http.Request) {
	user := middleware.GetUser(r)
	if user == nil {
		Error(w, http.StatusUnauthorized, "not authenticated")
		return
	}
	archived := r.URL.Query().Get("archived") == "true"

	// 管理员可用 ?all=true 查看全部
	scope := user.Username
	if user.IsAdmin() && r.URL.Query().Get("all") == "true" {
		scope = ""
	}

	contacts, err := repo.ListContactsFor(r.Context(), scope, archived)
	if err != nil {
		Error(w, http.StatusInternalServerError, "Failed to list contacts")
		return
	}
	JSON(w, http.StatusOK, map[string]interface{}{
		"contacts": emptySlice(contacts),
	})
}

type archiveRequest struct {
	Address   string `json:"address"`
	SessionID string `json:"session_id"`
}

// POST /api/v1/contacts/archive
// 归档指定 name@path.session：Agent 侧会话归档 + 邮箱界面移除
func ArchiveContact(w http.ResponseWriter, r *http.Request) {
	user := middleware.GetUser(r)
	if user == nil {
		Error(w, http.StatusUnauthorized, "not authenticated")
		return
	}

	var req archiveRequest
	if err := Decode(r, &req); err != nil {
		Error(w, http.StatusBadRequest, "Invalid JSON")
		return
	}

	var sessionID uuid.UUID
	switch {
	case req.SessionID != "":
		id, err := uuid.Parse(req.SessionID)
		if err != nil {
			Error(w, http.StatusBadRequest, "Invalid session_id")
			return
		}
		sessionID = id

	case req.Address != "":
		addr, err := models.ParseAddress(req.Address)
		if err != nil {
			Error(w, http.StatusBadRequest, "Invalid address: "+err.Error())
			return
		}
		id, err := repo.FindSessionByAddress(r.Context(), addr.Name, addr.Path, addr.Session)
		if err != nil {
			Error(w, http.StatusNotFound, "No session matches "+req.Address)
			return
		}
		sessionID = id

	default:
		Error(w, http.StatusBadRequest, "Provide address or session_id")
		return
	}

	// 鉴权：只能归档自己参与的会话（管理员不限）
	allowed, err := repo.UserCanAccessSession(r.Context(), user, sessionID)
	if err != nil {
		Error(w, http.StatusInternalServerError, "Failed to check permission")
		return
	}
	if !allowed {
		Error(w, http.StatusForbidden, "无权归档他人的会话")
		return
	}

	session, err := repo.GetSessionByID(r.Context(), sessionID)
	if err != nil {
		Error(w, http.StatusNotFound, "Session not found")
		return
	}
	mails, _ := repo.GetSessionMails(r.Context(), sessionID)

	if err := repo.ArchiveSession(r.Context(), sessionID); err != nil {
		Error(w, http.StatusInternalServerError, "Failed to archive session")
		return
	}

	alias := ""
	if session.Alias != nil {
		alias = *session.Alias
	}
	payload := map[string]interface{}{
		"session_id":    sessionID.String(),
		"session_alias": alias,
		"archived_by":   user.Username,
	}

	// 通知会话内所有参与方（Agent 与人类），各自归档/移除
	notified := map[string]bool{}
	for _, m := range mails {
		names := append([]string{m.FromName, m.ToName}, ccNames(m.CCList)...)
		for _, name := range names {
			if name == "" || notified[name] {
				continue
			}
			notified[name] = true
			sse.Default.SendToRecipient(name, "session_archived", payload)
		}
	}
	if !notified[user.Username] {
		sse.Default.SendToUser(user.Username, "session_archived", payload)
	}

	JSON(w, http.StatusOK, map[string]interface{}{
		"status":        "archived",
		"session_id":    sessionID.String(),
		"session_alias": alias,
	})
}

// GET /api/v1/contacts/suggest?name=xxx&path=yyy
// 三段式补全：无 name 给 Agent+人类用户名；有 name 给工作区；两者都有给会话别名(含 new)
func SuggestAddress(w http.ResponseWriter, r *http.Request) {
	user := middleware.GetUser(r)
	if user == nil {
		Error(w, http.StatusUnauthorized, "not authenticated")
		return
	}

	name := r.URL.Query().Get("name")
	path := r.URL.Query().Get("path")

	if name == "" {
		agents, err := repo.ListAgents(r.Context(), "")
		if err != nil {
			Error(w, http.StatusInternalServerError, "Failed to list agents")
			return
		}
		users, _ := repo.ListActiveUsernames(r.Context())

		names := make([]string, 0, len(agents)+len(users))
		for _, a := range agents {
			names = append(names, a.Name)
		}
		for _, u := range users {
			if u == user.Username {
				continue // 不建议给自己发信
			}
			names = append(names, u)
		}
		JSON(w, http.StatusOK, map[string]interface{}{
			"kind":        "name",
			"suggestions": emptySlice(names),
		})
		return
	}

	if path == "" {
		// 人类用户没有工作区，直接给空列表（前端会继续走 session 段）
		paths, _ := repo.SuggestPaths(r.Context(), name)
		JSON(w, http.StatusOK, map[string]interface{}{
			"kind":        "path",
			"suggestions": emptySlice(paths),
		})
		return
	}

	sessions, _ := repo.SuggestSessionsFor(r.Context(), user.Username, name, path)
	sessions = append(sessions, "new")
	JSON(w, http.StatusOK, map[string]interface{}{
		"kind":        "session",
		"suggestions": sessions,
	})
}

func ccNames(list []models.Address) []string {
	out := make([]string, 0, len(list))
	for _, a := range list {
		if a.Name != "" {
			out = append(out, a.Name)
		}
	}
	return out
}