// backend\search.go

package main

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

type globalSearchResponse struct {
	Query  string              `json:"query"`
	Groups []globalSearchGroup `json:"groups"`
}

type globalSearchGroup struct {
	ID    string             `json:"id"`
	Title string             `json:"title"`
	Items []globalSearchItem `json:"items"`
}

type globalSearchItem struct {
	ID         string         `json:"id"`
	EntityID   string         `json:"entityId"`
	EntityType string         `json:"entityType"`
	Title      string         `json:"title"`
	Subtitle   string         `json:"subtitle"`
	Href       string         `json:"href"`
	Data       map[string]any `json:"data,omitempty"`
}

func (s *Server) handleGlobalSearch(w http.ResponseWriter, r *http.Request) {
	user, ok := userFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "Unauthorized")
		return
	}

	query := strings.TrimSpace(r.URL.Query().Get("q"))
	limit := parseSearchLimit(r.URL.Query().Get("limit"), 8)

	if len([]rune(query)) < 2 {
		writeJSON(w, http.StatusOK, globalSearchResponse{
			Query:  query,
			Groups: []globalSearchGroup{},
		})
		return
	}

	groups := make([]globalSearchGroup, 0, 3)

	if userCanSearch(user, "operations:read") {
		items, err := s.searchOperations(r.Context(), query, limit)
		if err != nil {
			writeError(w, http.StatusInternalServerError, "Einsätze konnten nicht durchsucht werden")
			return
		}

		if len(items) > 0 {
			groups = append(groups, globalSearchGroup{
				ID:    "operations",
				Title: "Einsätze",
				Items: items,
			})
		}
	}

	if userCanSearch(user, "devices:read") {
		items, err := s.searchDevices(r.Context(), query, limit)
		if err != nil {
			writeError(w, http.StatusInternalServerError, "Geräte konnten nicht durchsucht werden")
			return
		}

		if len(items) > 0 {
			groups = append(groups, globalSearchGroup{
				ID:    "devices",
				Title: "Geräte",
				Items: items,
			})
		}
	}

	if userCanSearch(user, "users:read") {
		items, err := s.searchUsers(r.Context(), query, limit)
		if err != nil {
			writeError(w, http.StatusInternalServerError, "Benutzer konnten nicht durchsucht werden")
			return
		}

		if len(items) > 0 {
			groups = append(groups, globalSearchGroup{
				ID:    "users",
				Title: "Benutzer",
				Items: items,
			})
		}
	}

	writeJSON(w, http.StatusOK, globalSearchResponse{
		Query:  query,
		Groups: groups,
	})
}

func (s *Server) searchOperations(ctx context.Context, query string, limit int) ([]globalSearchItem, error) {
	pattern := "%" + query + "%"

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			id::TEXT,
			operation_number,
			operation_name,
			offense,
			kw_address,
			operation_leader,
			operation_team
		FROM operations
		WHERE CONCAT_WS(
			' ',
			operation_number,
			operation_name,
			offense,
			case_worker,
			target_object,
			kw_address,
			operation_leader,
			operation_team,
			legend,
			remark
		) ILIKE $1
		ORDER BY updated_at DESC
		LIMIT $2
		`,
		pattern,
		limit,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	items := []globalSearchItem{}

	for rows.Next() {
		var id string
		var operationNumber string
		var operationName string
		var offense string
		var kwAddress string
		var operationLeader string
		var operationTeam string

		if err := rows.Scan(
			&id,
			&operationNumber,
			&operationName,
			&offense,
			&kwAddress,
			&operationLeader,
			&operationTeam,
		); err != nil {
			return nil, err
		}

		title := operationName
		if strings.TrimSpace(title) == "" {
			title = operationNumber
		}

		subtitle := joinSearchSubtitle(
			operationNumber,
			offense,
			kwAddress,
			operationLeader,
			operationTeam,
		)

		items = append(items, globalSearchItem{
			ID:         "operation-" + id,
			EntityID:   id,
			EntityType: "operation",
			Title:      title,
			Subtitle:   subtitle,
			Href:       "/einsaetze",
			Data: map[string]any{
				"operationNumber": operationNumber,
			},
		})
	}

	return items, rows.Err()
}

func (s *Server) searchDevices(ctx context.Context, query string, limit int) ([]globalSearchItem, error) {
	pattern := "%" + query + "%"

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			id::TEXT,
			inventory_number,
			manufacturer,
			model,
			serial_number,
			mac_address,
			location,
			loan_status
		FROM devices
		WHERE CONCAT_WS(
			' ',
			inventory_number,
			manufacturer,
			model,
			serial_number,
			mac_address,
			location,
			loan_status,
			comment
		) ILIKE $1
		ORDER BY updated_at DESC
		LIMIT $2
		`,
		pattern,
		limit,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	items := []globalSearchItem{}

	for rows.Next() {
		var id string
		var inventoryNumber string
		var manufacturer string
		var model string
		var serialNumber string
		var macAddress string
		var location string
		var loanStatus string

		if err := rows.Scan(
			&id,
			&inventoryNumber,
			&manufacturer,
			&model,
			&serialNumber,
			&macAddress,
			&location,
			&loanStatus,
		); err != nil {
			return nil, err
		}

		items = append(items, globalSearchItem{
			ID:         "device-" + id,
			EntityID:   id,
			EntityType: "device",
			Title:      inventoryNumber,
			Subtitle: joinSearchSubtitle(
				manufacturer,
				model,
				serialNumber,
				macAddress,
				location,
				loanStatus,
			),
			Href: "/geraete",
			Data: map[string]any{
				"inventoryNumber": inventoryNumber,
			},
		})
	}

	return items, rows.Err()
}

func (s *Server) searchUsers(ctx context.Context, query string, limit int) ([]globalSearchItem, error) {
	pattern := "%" + query + "%"

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			id::TEXT,
			COALESCE(username, ''),
			COALESCE(display_name, ''),
			email,
			COALESCE(unit, ''),
			COALESCE(user_group, '')
		FROM users
		WHERE CONCAT_WS(
			' ',
			username,
			display_name,
			email,
			unit,
			user_group
		) ILIKE $1
		ORDER BY display_name ASC, username ASC, email ASC
		LIMIT $2
		`,
		pattern,
		limit,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	items := []globalSearchItem{}

	for rows.Next() {
		var id string
		var username string
		var displayName string
		var email string
		var unit string
		var group string

		if err := rows.Scan(
			&id,
			&username,
			&displayName,
			&email,
			&unit,
			&group,
		); err != nil {
			return nil, err
		}

		title := displayName
		if strings.TrimSpace(title) == "" {
			title = username
		}
		if strings.TrimSpace(title) == "" {
			title = email
		}

		items = append(items, globalSearchItem{
			ID:         "user-" + id,
			EntityID:   id,
			EntityType: "user",
			Title:      title,
			Subtitle:   joinSearchSubtitle(email, unit, group),
			Href:       "/administration",
			Data: map[string]any{
				"username": username,
				"email":    email,
			},
		})
	}

	return items, rows.Err()
}

func parseSearchLimit(value string, fallback int) int {
	limit, err := strconv.Atoi(value)
	if err != nil {
		return fallback
	}

	if limit < 1 {
		return fallback
	}

	if limit > 25 {
		return 25
	}

	return limit
}

func userCanSearch(user User, right string) bool {
	for _, userRight := range user.Rights {
		if userRight == "admin" || userRight == right {
			return true
		}
	}

	return false
}

func joinSearchSubtitle(values ...string) string {
	parts := make([]string, 0, len(values))

	for _, value := range values {
		value = strings.TrimSpace(value)
		if value != "" {
			parts = append(parts, value)
		}
	}

	return strings.Join(parts, " · ")
}