package handler

import (
	"errors"
	"net/http"
	"strconv"

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

	"github.com/yuxingu/digital-psychology/apps/api/internal/middleware"
	"github.com/yuxingu/digital-psychology/apps/api/internal/repository"
	"github.com/yuxingu/digital-psychology/apps/api/internal/service/admin"
	"github.com/yuxingu/digital-psychology/apps/api/internal/service/analytics"
	"github.com/yuxingu/digital-psychology/apps/api/pkg/response"
)

// AdminHandler serves /api/v1/admin/* (no DeviceAuth).
type AdminHandler struct {
	Svc       *admin.Service
	Analytics *analytics.Service
}

// Register mounts public login + authed admin routes.
func (h *AdminHandler) Register(api *gin.RouterGroup) {
	g := api.Group("/admin")
	g.POST("/auth/login", h.Login)

	authed := g.Group("")
	authed.Use(middleware.AdminAuth(h.Svc))
	authed.POST("/auth/logout", h.Logout)
	authed.GET("/me", h.Me)
	authed.GET("/stats", middleware.RequireAdminPermission(h.Svc, admin.PermUsersRead), h.Stats)
	authed.GET("/users", middleware.RequireAdminPermission(h.Svc, admin.PermUsersRead), h.ListUsers)
	authed.GET("/users/:id", middleware.RequireAdminPermission(h.Svc, admin.PermUsersRead), h.GetUser)
	authed.POST("/users/:id/membership/grant", middleware.RequireAdminPermission(h.Svc, admin.PermMembershipGrant), h.GrantMembership)
	authed.POST("/users/:id/ask-quota/grant", middleware.RequireAdminPermission(h.Svc, admin.PermAskQuotaGrant), h.GrantAskQuota)
	authed.GET("/orders", middleware.RequireAdminPermission(h.Svc, admin.PermOrdersRead), h.ListOrders)
	authed.GET("/membership/plan-prices", h.ListPlanPrices)
	authed.PUT("/membership/plan-prices", h.PutPlanPrices)
	authed.GET("/audit-logs", middleware.RequireAdminPermission(h.Svc, admin.PermAuditRead), h.ListAudit)
	authed.GET("/analytics/overview", middleware.RequireAdminPermission(h.Svc, admin.PermAnalyticsRead), h.AnalyticsOverview)
	authed.GET("/analytics/pages", middleware.RequireAdminPermission(h.Svc, admin.PermAnalyticsRead), h.AnalyticsPages)
	authed.GET("/analytics/exits", middleware.RequireAdminPermission(h.Svc, admin.PermAnalyticsRead), h.AnalyticsExits)
	authed.GET("/analytics/clicks", middleware.RequireAdminPermission(h.Svc, admin.PermAnalyticsRead), h.AnalyticsClicks)
	authed.GET("/analytics/funnel", middleware.RequireAdminPermission(h.Svc, admin.PermAnalyticsRead), h.AnalyticsFunnel)
	h.registerContent(authed)
	h.registerSystem(authed)
	h.registerRBAC(authed)
	h.registerLifecycle(authed)
	h.registerMembershipPlans(authed)
	h.registerRedemption(authed)
	h.registerInsight(authed)
	h.registerAskOps(authed)
	h.registerQualityFeedback(authed)
	h.registerEntitlement(authed)
	h.registerContentSafety(authed)
	h.registerAIConfig(authed)
	h.registerCrisis(authed)
	h.registerCMS(authed)
	h.registerCMSPublications(authed)
	h.registerKnowledgeChunks(authed)
	h.registerToolDefinitions(authed)
	h.registerBlockPolicies(authed)
	h.registerModerationCases(authed)
	h.registerCrisisEvents(authed)
	h.registerInterventionOutcomes(authed)
	h.registerHandoffCases(authed)
	h.registerPrivacyRequests(authed)
	h.registerStarConfigs(authed)
	h.registerRhythmConfigs(authed)
	h.registerImageCardDecks(authed)
	h.registerReportTemplates(authed)
	h.registerFunnelDefinitions(authed)
	h.registerExploreScales(authed)
}

func (h *AdminHandler) Login(c *gin.Context) {
	var body struct {
		Username string `json:"username"`
		Password string `json:"password"`
	}
	if err := c.ShouldBindJSON(&body); err != nil || body.Username == "" || body.Password == "" {
		response.Fail(c, http.StatusBadRequest, 40001, "username and password required")
		return
	}
	res, err := h.Svc.Login(c.Request.Context(), body.Username, body.Password)
	if err != nil {
		if errors.Is(err, admin.ErrBadCredentials) {
			response.Fail(c, http.StatusUnauthorized, 40103, "invalid credentials")
			return
		}
		response.Fail(c, http.StatusInternalServerError, 50010, "login failed")
		return
	}
	response.OK(c, res)
}

func (h *AdminHandler) Logout(c *gin.Context) {
	token := middleware.BearerToken(c.GetHeader("Authorization"))
	_ = h.Svc.Logout(c.Request.Context(), token)
	response.OK(c, gin.H{"ok": true})
}

func (h *AdminHandler) Me(c *gin.Context) {
	adminID, ok := middleware.AdminIDFromContext(c)
	if !ok {
		response.Fail(c, http.StatusUnauthorized, 40101, "admin auth required")
		return
	}
	me, err := h.Svc.Me(c.Request.Context(), adminID)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50011, "me failed")
		return
	}
	response.OK(c, me)
}

func (h *AdminHandler) Stats(c *gin.Context) {
	stats, err := h.Svc.DashboardStats(c.Request.Context())
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50017, "stats failed")
		return
	}
	response.OK(c, stats)
}

func (h *AdminHandler) ListUsers(c *gin.Context) {
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))
	items, err := h.Svc.ListUsers(c.Request.Context(), c.Query("q"), limit, offset)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50012, "list users failed")
		return
	}
	response.OK(c, gin.H{"items": items})
}

func (h *AdminHandler) GetUser(c *gin.Context) {
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40002, "invalid user id")
		return
	}
	detail, err := h.Svc.GetUser(c.Request.Context(), id)
	if err != nil {
		if errors.Is(err, admin.ErrUserNotFound) {
			response.Fail(c, http.StatusNotFound, 40401, "user not found")
			return
		}
		response.Fail(c, http.StatusInternalServerError, 50013, "get user failed")
		return
	}
	response.OK(c, detail)
}

func (h *AdminHandler) GrantMembership(c *gin.Context) {
	adminID, ok := middleware.AdminIDFromContext(c)
	if !ok {
		response.Fail(c, http.StatusUnauthorized, 40101, "admin auth required")
		return
	}
	userID, err := uuid.Parse(c.Param("id"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40002, "invalid user id")
		return
	}
	var body admin.GrantInput
	if err := c.ShouldBindJSON(&body); err != nil || body.Plan == "" {
		response.Fail(c, http.StatusBadRequest, 40003, "plan required")
		return
	}
	if err := h.Svc.GrantMembership(c.Request.Context(), adminID, userID, body.Plan); err != nil {
		if errors.Is(err, admin.ErrForbidden) {
			response.Fail(c, http.StatusForbidden, 40301, "forbidden")
			return
		}
		if errors.Is(err, admin.ErrInvalidPlan) {
			response.Fail(c, http.StatusBadRequest, 40004, "invalid plan")
			return
		}
		if errors.Is(err, admin.ErrUserNotFound) {
			response.Fail(c, http.StatusNotFound, 40401, "user not found")
			return
		}
		response.Fail(c, http.StatusInternalServerError, 50014, "grant failed")
		return
	}
	response.OK(c, gin.H{"ok": true})
}

func (h *AdminHandler) GrantAskQuota(c *gin.Context) {
	adminID, ok := middleware.AdminIDFromContext(c)
	if !ok {
		response.Fail(c, http.StatusUnauthorized, 40101, "admin auth required")
		return
	}
	userID, err := uuid.Parse(c.Param("id"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40002, "invalid user id")
		return
	}
	var body admin.GrantAskQuotaInput
	if err := c.ShouldBindJSON(&body); err != nil {
		response.Fail(c, http.StatusBadRequest, 40005, "delta required")
		return
	}
	left, err := h.Svc.GrantAskQuota(c.Request.Context(), adminID, userID, body.Delta)
	if err != nil {
		if errors.Is(err, admin.ErrForbidden) {
			response.Fail(c, http.StatusForbidden, 40301, "forbidden")
			return
		}
		if errors.Is(err, admin.ErrInvalidAskDelta) {
			response.Fail(c, http.StatusBadRequest, 40006, "invalid delta")
			return
		}
		if errors.Is(err, admin.ErrUserNotFound) {
			response.Fail(c, http.StatusNotFound, 40401, "user not found")
			return
		}
		response.Fail(c, http.StatusInternalServerError, 50018, "grant ask quota failed")
		return
	}
	response.OK(c, gin.H{"ok": true, "ask_paid_quota_left": left})
}

func (h *AdminHandler) ListOrders(c *gin.Context) {
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))
	f := admin.OrderFilterFromQuery(
		c.Query("user_id"),
		c.Query("status"),
		c.Query("kind"),
		c.Query("from"),
		c.Query("to"),
		limit,
		offset,
	)
	items, err := h.Svc.ListOrders(c.Request.Context(), f)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50015, "list orders failed")
		return
	}
	response.OK(c, gin.H{"items": items})
}

func (h *AdminHandler) ListPlanPrices(c *gin.Context) {
	items, err := h.Svc.ListPlanPrices(c.Request.Context())
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50017, "list plan prices failed")
		return
	}
	response.OK(c, gin.H{"items": items})
}

func (h *AdminHandler) PutPlanPrices(c *gin.Context) {
	adminID, ok := middleware.AdminIDFromContext(c)
	if !ok {
		response.Fail(c, http.StatusUnauthorized, 40101, "admin auth required")
		return
	}
	var body struct {
		Items []struct {
			Plan         string `json:"plan"`
			DisplayCents int    `json:"display_cents"`
		} `json:"items"`
	}
	if err := c.ShouldBindJSON(&body); err != nil || len(body.Items) == 0 {
		response.Fail(c, http.StatusBadRequest, 40040, "items required")
		return
	}
	prices := make([]repository.PlanPrice, 0, len(body.Items))
	for _, it := range body.Items {
		prices = append(prices, repository.PlanPrice{Plan: it.Plan, DisplayCents: it.DisplayCents})
	}
	if err := h.Svc.UpsertPlanPrices(c.Request.Context(), adminID, prices); err != nil {
		if errors.Is(err, admin.ErrForbidden) {
			response.Fail(c, http.StatusForbidden, 40301, "forbidden")
			return
		}
		response.Fail(c, http.StatusBadRequest, 40041, "upsert plan prices failed")
		return
	}
	response.OK(c, gin.H{"ok": true})
}

func (h *AdminHandler) ListAudit(c *gin.Context) {
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))
	items, err := h.Svc.ListAuditLogs(c.Request.Context(), limit, offset)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50016, "list audit failed")
		return
	}
	response.OK(c, gin.H{"items": items})
}

func (h *AdminHandler) AnalyticsOverview(c *gin.Context) {
	from, to, err := analytics.ParseDayRange(c.Query("from"), c.Query("to"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40030, "invalid from/to")
		return
	}
	if !h.requireAnalytics(c) {
		return
	}
	data, err := h.Analytics.Overview(c.Request.Context(), from, to)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50022, "overview failed")
		return
	}
	response.OK(c, data)
}

func (h *AdminHandler) AnalyticsPages(c *gin.Context) {
	from, to, err := analytics.ParseDayRange(c.Query("from"), c.Query("to"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40030, "invalid from/to")
		return
	}
	if !h.requireAnalytics(c) {
		return
	}
	items, err := h.Analytics.Pages(c.Request.Context(), from, to)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50023, "pages failed")
		return
	}
	response.OK(c, gin.H{"items": items})
}

func (h *AdminHandler) AnalyticsExits(c *gin.Context) {
	from, to, err := analytics.ParseDayRange(c.Query("from"), c.Query("to"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40030, "invalid from/to")
		return
	}
	if !h.requireAnalytics(c) {
		return
	}
	items, err := h.Analytics.Exits(c.Request.Context(), from, to)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50024, "exits failed")
		return
	}
	response.OK(c, gin.H{"items": items})
}

func (h *AdminHandler) AnalyticsClicks(c *gin.Context) {
	from, to, err := analytics.ParseDayRange(c.Query("from"), c.Query("to"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40030, "invalid from/to")
		return
	}
	if !h.requireAnalytics(c) {
		return
	}
	items, err := h.Analytics.Clicks(c.Request.Context(), from, to)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50025, "clicks failed")
		return
	}
	response.OK(c, gin.H{"items": items})
}

func (h *AdminHandler) AnalyticsFunnel(c *gin.Context) {
	from, to, err := analytics.ParseDayRange(c.Query("from"), c.Query("to"))
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 40030, "invalid from/to")
		return
	}
	if !h.requireAnalytics(c) {
		return
	}
	steps, err := h.Analytics.Funnel(c.Request.Context(), from, to)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50026, "funnel failed")
		return
	}
	response.OK(c, gin.H{"steps": steps})
}

func (h *AdminHandler) requireAnalytics(c *gin.Context) bool {
	if h.Analytics == nil {
		response.Fail(c, http.StatusInternalServerError, 50021, "analytics unavailable")
		return false
	}
	return true
}