package moderation

import (
	"net/http"
	"strconv"
	"strings"

	apperrors "veza-backend-api/internal/errors"
	"veza-backend-api/internal/handlers"
	"veza-backend-api/internal/services"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"go.uber.org/zap"
)

// ModerationHandler handles advanced moderation HTTP requests (F411-F420)
type ModerationHandler struct {
	service *services.ModerationService
	logger  *zap.Logger
}

// NewModerationHandler creates a new moderation handler
func NewModerationHandler(service *services.ModerationService, logger *zap.Logger) *ModerationHandler {
	if logger == nil {
		logger = zap.NewNop()
	}
	return &ModerationHandler{service: service, logger: logger}
}

// getModeratorID extracts the moderator's user ID from context
func (h *ModerationHandler) getModeratorID(c *gin.Context) (uuid.UUID, bool) {
	userID, ok := handlers.GetUserIDUUID(c)
	if !ok || userID == uuid.Nil {
		handlers.RespondWithAppError(c, apperrors.New(apperrors.ErrCodeUnauthorized, "authentication required"))
		return uuid.Nil, false
	}
	return userID, true
}

// --- F411: Moderation Queue ---

// GetModerationQueue handles GET /api/v1/admin/moderation/queue (F411)
func (h *ModerationHandler) GetModerationQueue(c *gin.Context) {
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))

	params := services.ModerationQueueParams{
		Status:   c.DefaultQuery("status", "pending"),
		Category: c.Query("category"),
		Priority: c.Query("priority"),
		Limit:    limit,
		Offset:   offset,
		SortBy:   c.DefaultQuery("sort_by", "created_at"),
	}

	items, total, err := h.service.GetModerationQueue(c.Request.Context(), params)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to get moderation queue", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"reports": items,
		"pagination": gin.H{
			"total":  total,
			"limit":  limit,
			"offset": offset,
		},
	})
}

// ProcessReport handles POST /api/v1/admin/moderation/reports/:id/process (F411)
func (h *ModerationHandler) ProcessReport(c *gin.Context) {
	moderatorID, ok := h.getModeratorID(c)
	if !ok {
		return
	}

	reportIDStr := c.Param("id")
	reportID, err := uuid.Parse(reportIDStr)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid report ID"))
		return
	}

	var action services.ModerationAction
	if err := c.ShouldBindJSON(&action); err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("action is required"))
		return
	}

	validActions := map[string]bool{
		"approve": true, "reject": true, "ban_temp": true,
		"ban_perm": true, "warn": true, "dismiss": true,
	}
	if !validActions[action.Action] {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid action: must be approve, reject, ban_temp, ban_perm, warn, or dismiss"))
		return
	}

	if err := h.service.ProcessReport(c.Request.Context(), reportID, moderatorID, action); err != nil {
		if strings.Contains(err.Error(), "not found") {
			handlers.RespondWithAppError(c, apperrors.NewNotFoundError("report"))
			return
		}
		if strings.Contains(err.Error(), "already processed") {
			handlers.RespondWithAppError(c, apperrors.NewValidationError("report already processed"))
			return
		}
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to process report", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"status": "processed",
	})
}

// AssignReport handles POST /api/v1/admin/moderation/reports/:id/assign (F411)
func (h *ModerationHandler) AssignReport(c *gin.Context) {
	reportIDStr := c.Param("id")
	reportID, err := uuid.Parse(reportIDStr)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid report ID"))
		return
	}

	var req struct {
		ModeratorID string `json:"moderator_id" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("moderator_id is required"))
		return
	}

	moderatorID, err := uuid.Parse(req.ModeratorID)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid moderator ID"))
		return
	}

	if err := h.service.AssignReport(c.Request.Context(), reportID, moderatorID); err != nil {
		if strings.Contains(err.Error(), "not found") {
			handlers.RespondWithAppError(c, apperrors.NewNotFoundError("report"))
			return
		}
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to assign report", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"status": "assigned",
	})
}

// --- F412: Enhanced Reporting ---

// CreateEnhancedReport handles POST /api/v1/reports (F412)
// Available to all authenticated users
func (h *ModerationHandler) CreateEnhancedReport(c *gin.Context) {
	userID, ok := h.getModeratorID(c)
	if !ok {
		return
	}

	var req services.EnhancedReportRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("content_type, category, and reason are required"))
		return
	}

	reportID, err := h.service.CreateEnhancedReport(c.Request.Context(), userID, req)
	if err != nil {
		if strings.Contains(err.Error(), "invalid category") || strings.Contains(err.Error(), "invalid content type") {
			handlers.RespondWithAppError(c, apperrors.NewValidationError(err.Error()))
			return
		}
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to create report", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusCreated, gin.H{
		"id":     reportID.String(),
		"status": "created",
	})
}

// --- F413: Spam Detection ---

// GetSpamDetections handles GET /api/v1/admin/moderation/spam (F413)
func (h *ModerationHandler) GetSpamDetections(c *gin.Context) {
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))
	if limit > 100 {
		limit = 100
	}

	var total int64
	var detections []struct {
		ID          string `json:"id"`
		UserID      string `json:"user_id"`
		RuleName    string `json:"rule_name"`
		ContentType string `json:"content_type"`
		ActionTaken string `json:"action_taken"`
		Reviewed    bool   `json:"reviewed"`
		CreatedAt   string `json:"created_at"`
	}

	db := h.service.DB()
	db.WithContext(c.Request.Context()).Table("spam_detections").Where("reviewed = FALSE").Count(&total)

	if err := db.WithContext(c.Request.Context()).Raw(`
		SELECT CAST(sd.id AS TEXT), CAST(sd.user_id AS TEXT) AS user_id,
			   sr.name AS rule_name, sd.content_type, sd.action_taken, sd.reviewed,
			   sd.created_at::text
		FROM spam_detections sd
		JOIN spam_rules sr ON sr.id = sd.rule_id
		WHERE sd.reviewed = FALSE
		ORDER BY sd.created_at DESC
		LIMIT ? OFFSET ?
	`, limit, offset).Scan(&detections).Error; err != nil {
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to get spam detections", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"detections": detections,
		"pagination": gin.H{
			"total":  total,
			"limit":  limit,
			"offset": offset,
		},
	})
}

// --- F414: Audio Fingerprints ---

// GetPendingFingerprints handles GET /api/v1/admin/moderation/fingerprints (F414)
func (h *ModerationHandler) GetPendingFingerprints(c *gin.Context) {
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))

	fingerprints, total, err := h.service.GetPendingFingerprints(c.Request.Context(), limit, offset)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to get fingerprints", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"fingerprints": fingerprints,
		"pagination": gin.H{
			"total":  total,
			"limit":  limit,
			"offset": offset,
		},
	})
}

// ReviewFingerprint handles POST /api/v1/admin/moderation/fingerprints/:trackId/review (F414)
func (h *ModerationHandler) ReviewFingerprint(c *gin.Context) {
	reviewerID, ok := h.getModeratorID(c)
	if !ok {
		return
	}

	trackIDStr := c.Param("trackId")
	trackID, err := uuid.Parse(trackIDStr)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid track ID"))
		return
	}

	var req struct {
		Status string `json:"status" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("status is required"))
		return
	}

	if err := h.service.ReviewFingerprint(c.Request.Context(), trackID, reviewerID, req.Status); err != nil {
		if strings.Contains(err.Error(), "invalid status") {
			handlers.RespondWithAppError(c, apperrors.NewValidationError(err.Error()))
			return
		}
		if strings.Contains(err.Error(), "not found") {
			handlers.RespondWithAppError(c, apperrors.NewNotFoundError("fingerprint"))
			return
		}
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to review fingerprint", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"status": "reviewed",
	})
}

// --- F415: Strike System ---

// GetUserStrikes handles GET /api/v1/admin/moderation/users/:userId/strikes (F415)
func (h *ModerationHandler) GetUserStrikes(c *gin.Context) {
	userIDStr := c.Param("userId")
	userID, err := uuid.Parse(userIDStr)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid user ID"))
		return
	}

	summary, err := h.service.GetUserStrikes(c.Request.Context(), userID)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to get strikes", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"strikes": summary,
	})
}

// GetPendingAppeals handles GET /api/v1/admin/moderation/appeals (F415)
func (h *ModerationHandler) GetPendingAppeals(c *gin.Context) {
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))

	appeals, total, err := h.service.GetPendingAppeals(c.Request.Context(), limit, offset)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to get appeals", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"appeals": appeals,
		"pagination": gin.H{
			"total":  total,
			"limit":  limit,
			"offset": offset,
		},
	})
}

// ResolveAppeal handles POST /api/v1/admin/moderation/appeals/:strikeId/resolve (F415)
func (h *ModerationHandler) ResolveAppeal(c *gin.Context) {
	resolverID, ok := h.getModeratorID(c)
	if !ok {
		return
	}

	strikeIDStr := c.Param("strikeId")
	strikeID, err := uuid.Parse(strikeIDStr)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid strike ID"))
		return
	}

	var req struct {
		Upheld bool `json:"upheld"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("upheld field is required"))
		return
	}

	if err := h.service.ResolveAppeal(c.Request.Context(), strikeID, resolverID, req.Upheld); err != nil {
		if strings.Contains(err.Error(), "not found") || strings.Contains(err.Error(), "already resolved") {
			handlers.RespondWithAppError(c, apperrors.NewNotFoundError("appeal"))
			return
		}
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to resolve appeal", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"status": "resolved",
	})
}

// --- User-facing: Appeals ---

// AppealStrike handles POST /api/v1/strikes/:strikeId/appeal (F415)
// Available to authenticated users for their own strikes
func (h *ModerationHandler) AppealStrike(c *gin.Context) {
	userID, ok := h.getModeratorID(c)
	if !ok {
		return
	}

	strikeIDStr := c.Param("strikeId")
	strikeID, err := uuid.Parse(strikeIDStr)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("invalid strike ID"))
		return
	}

	var req struct {
		AppealText string `json:"appeal_text" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		handlers.RespondWithAppError(c, apperrors.NewValidationError("appeal_text is required"))
		return
	}

	if err := h.service.AppealStrike(c.Request.Context(), userID, strikeID, req.AppealText); err != nil {
		if strings.Contains(err.Error(), "not found") || strings.Contains(err.Error(), "already appealed") {
			handlers.RespondWithAppError(c, apperrors.NewValidationError(err.Error()))
			return
		}
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to submit appeal", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"status": "appeal_submitted",
	})
}

// GetMyStrikes handles GET /api/v1/me/strikes (F415)
// Returns the authenticated user's own strikes
func (h *ModerationHandler) GetMyStrikes(c *gin.Context) {
	userID, ok := h.getModeratorID(c)
	if !ok {
		return
	}

	summary, err := h.service.GetUserStrikes(c.Request.Context(), userID)
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to get strikes", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"strikes": summary,
	})
}

// --- Moderation Stats ---

// GetModerationStats handles GET /api/v1/admin/moderation/stats
func (h *ModerationHandler) GetModerationStats(c *gin.Context) {
	stats, err := h.service.GetModerationStats(c.Request.Context())
	if err != nil {
		handlers.RespondWithAppError(c, apperrors.Wrap(apperrors.ErrCodeInternal, "failed to get stats", err))
		return
	}

	handlers.RespondSuccess(c, http.StatusOK, gin.H{
		"stats": stats,
	})
}