// backend\search.go

package main

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

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"`
}

type globalSearchOptions struct {
	Query         string
	Limit         int
	ExactPhrase   bool
	CaseSensitive bool
}

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"))

	options := globalSearchOptions{
		Query:         query,
		Limit:         parseSearchLimit(r.URL.Query().Get("limit"), 8),
		ExactPhrase:   parseSearchBool(r.URL.Query().Get("exact")),
		CaseSensitive: parseSearchBool(r.URL.Query().Get("caseSensitive")),
	}

	if !strings.Contains(query, " ") {
		options.ExactPhrase = false
	}

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

	groups := make([]globalSearchGroup, 0, 5)

	if userCanSearch(user, "operations:read") {
		items, err := s.searchOperations(r.Context(), options)
		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, "operations:read") {
		items, err := s.searchOperationJournalEntries(r.Context(), options)
		if err != nil {
			writeError(w, http.StatusInternalServerError, "Einsatz-Journale konnten nicht durchsucht werden")
			return
		}

		if len(items) > 0 {
			groups = append(groups, globalSearchGroup{
				ID:    "operation-journals",
				Title: "Einsatz-Journale",
				Items: items,
			})
		}
	}

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

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

	if userCanSearch(user, "devices:read") {
		items, err := s.searchDevices(r.Context(), options)
		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(), options)
		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, options globalSearchOptions) ([]globalSearchItem, error) {
	patterns := buildSearchPatterns(options)

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			id::TEXT,
			operation_number,
			operation_name,
			offense,
			kw_address,
			operation_leader,
			operation_team
		FROM operations
		WHERE (
			(
				$3 = false
				AND CONCAT_WS(
					' ',
					operation_number,
					operation_name,
					offense,
					case_worker,
					target_object,
					kw_address,
					operation_leader,
					operation_team,
					legend,
					remark
				) ILIKE ALL($1::TEXT[])
			)
			OR
			(
				$3 = true
				AND CONCAT_WS(
					' ',
					operation_number,
					operation_name,
					offense,
					case_worker,
					target_object,
					kw_address,
					operation_leader,
					operation_team,
					legend,
					remark
				) LIKE ALL($1::TEXT[])
			)
		)
		ORDER BY updated_at DESC
		LIMIT $2
		`,
		patterns,
		options.Limit,
		options.CaseSensitive,
	)
	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, options globalSearchOptions) ([]globalSearchItem, error) {
	patterns := buildSearchPatterns(options)

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			id::TEXT,
			inventory_number,
			manufacturer,
			model,
			serial_number,
			mac_address,
			COALESCE(ip_address, ''),
			location,
			loan_status,
			COALESCE(firmware_version, '')
		FROM devices
		WHERE (
			(
				$3 = false
				AND CONCAT_WS(
					' ',
					inventory_number,
					manufacturer,
					model,
					serial_number,
					mac_address,
					COALESCE(ip_address, ''),
					location,
					loan_status,
					comment,
					COALESCE(firmware_version, '')
				) ILIKE ALL($1::TEXT[])
			)
			OR
			(
				$3 = true
				AND CONCAT_WS(
					' ',
					inventory_number,
					manufacturer,
					model,
					serial_number,
					mac_address,
					COALESCE(ip_address, ''),
					location,
					loan_status,
					comment,
					COALESCE(firmware_version, '')
				) LIKE ALL($1::TEXT[])
			)
		)
		ORDER BY updated_at DESC
		LIMIT $2
		`,
		patterns,
		options.Limit,
		options.CaseSensitive,
	)
	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 ipAddress string
		var location string
		var loanStatus string
		var firmwareVersion string

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

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

	return items, rows.Err()
}

func (s *Server) searchOperationJournalEntries(ctx context.Context, options globalSearchOptions) ([]globalSearchItem, error) {
	patterns := buildSearchPatterns(options)

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			operation_history.id::TEXT,
			operation_history.operation_id::TEXT,
			operations.operation_number,
			operations.operation_name,
			COALESCE(users.display_name, users.username, users.email, 'Unbekannt'),
			COALESCE(journal_change.change->>'newValue', ''),
			operation_history.created_at
		FROM operation_history
		INNER JOIN operations
			ON operations.id = operation_history.operation_id
		LEFT JOIN users
			ON users.id = operation_history.user_id
		CROSS JOIN LATERAL jsonb_array_elements(operation_history.changes) AS journal_change(change)
		WHERE
			journal_change.change->>'field' = 'journal'
			AND (
				(
					$3 = false
					AND journal_change.change->>'newValue' ILIKE ALL($1::TEXT[])
				)
				OR
				(
					$3 = true
					AND journal_change.change->>'newValue' LIKE ALL($1::TEXT[])
				)
			)
		ORDER BY operation_history.created_at DESC
		LIMIT $2
		`,
		patterns,
		options.Limit,
		options.CaseSensitive,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	items := []globalSearchItem{}

	for rows.Next() {
		var id string
		var operationID string
		var operationNumber string
		var operationName string
		var userDisplayName string
		var content string
		var createdAt time.Time

		if err := rows.Scan(
			&id,
			&operationID,
			&operationNumber,
			&operationName,
			&userDisplayName,
			&content,
			&createdAt,
		); err != nil {
			return nil, err
		}

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

		items = append(items, globalSearchItem{
			ID:         "operation-journal-" + id,
			EntityID:   operationID,
			EntityType: "operationJournal",
			Title:      title,
			Subtitle: joinSearchSubtitle(
				formatSearchDate(createdAt),
				userDisplayName,
				truncateSearchText(content, 140),
			),
			Href: "/einsaetze",
			Data: map[string]any{
				"historyId":        id,
				"operationId":      operationID,
				"operationNumber":  operationNumber,
				"journalCreatedAt": createdAt,
			},
		})
	}

	return items, rows.Err()
}

func (s *Server) searchDeviceJournalEntries(ctx context.Context, options globalSearchOptions) ([]globalSearchItem, error) {
	patterns := buildSearchPatterns(options)

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			device_history.id::TEXT,
			device_history.device_id::TEXT,
			devices.inventory_number,
			devices.manufacturer,
			devices.model,
			COALESCE(users.display_name, users.username, users.email, 'Unbekannt'),
			COALESCE(journal_change.change->>'newValue', ''),
			device_history.created_at
		FROM device_history
		INNER JOIN devices
			ON devices.id = device_history.device_id
		LEFT JOIN users
			ON users.id = device_history.user_id
		CROSS JOIN LATERAL jsonb_array_elements(device_history.changes) AS journal_change(change)
		WHERE
			journal_change.change->>'field' = 'journal'
			AND (
				(
					$3 = false
					AND journal_change.change->>'newValue' ILIKE ALL($1::TEXT[])
				)
				OR
				(
					$3 = true
					AND journal_change.change->>'newValue' LIKE ALL($1::TEXT[])
				)
			)
		ORDER BY device_history.created_at DESC
		LIMIT $2
		`,
		patterns,
		options.Limit,
		options.CaseSensitive,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	items := []globalSearchItem{}

	for rows.Next() {
		var id string
		var deviceID string
		var inventoryNumber string
		var manufacturer string
		var model string
		var userDisplayName string
		var content string
		var createdAt time.Time

		if err := rows.Scan(
			&id,
			&deviceID,
			&inventoryNumber,
			&manufacturer,
			&model,
			&userDisplayName,
			&content,
			&createdAt,
		); err != nil {
			return nil, err
		}

		deviceName := joinSearchSubtitle(manufacturer, model)

		items = append(items, globalSearchItem{
			ID:         "device-journal-" + id,
			EntityID:   deviceID,
			EntityType: "deviceJournal",
			Title:      inventoryNumber,
			Subtitle: joinSearchSubtitle(
				deviceName,
				formatSearchDate(createdAt),
				userDisplayName,
				truncateSearchText(content, 140),
			),
			Href: "/geraete",
			Data: map[string]any{
				"historyId":        id,
				"deviceId":         deviceID,
				"inventoryNumber":  inventoryNumber,
				"journalCreatedAt": createdAt,
			},
		})
	}

	return items, rows.Err()
}

func (s *Server) searchUsers(ctx context.Context, options globalSearchOptions) ([]globalSearchItem, error) {
	patterns := buildSearchPatterns(options)

	rows, err := s.db.Query(
		ctx,
		`
		SELECT
			id::TEXT,
			COALESCE(username, ''),
			COALESCE(display_name, ''),
			COALESCE(email, ''),
			COALESCE(unit, ''),
			COALESCE(user_group, '')
		FROM users
		WHERE (
			(
				$3 = false
				AND CONCAT_WS(
					' ',
					username,
					display_name,
					email,
					unit,
					user_group
				) ILIKE ALL($1::TEXT[])
			)
			OR
			(
				$3 = true
				AND CONCAT_WS(
					' ',
					username,
					display_name,
					email,
					unit,
					user_group
				) LIKE ALL($1::TEXT[])
			)
		)
		ORDER BY display_name ASC, username ASC, email ASC
		LIMIT $2
		`,
		patterns,
		options.Limit,
		options.CaseSensitive,
	)
	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 parseSearchBool(value string) bool {
	value = strings.ToLower(strings.TrimSpace(value))

	return value == "1" ||
		value == "true" ||
		value == "yes" ||
		value == "on"
}

func buildSearchPatterns(options globalSearchOptions) []string {
	query := strings.TrimSpace(options.Query)

	if query == "" {
		return []string{"%%"}
	}

	if options.ExactPhrase && strings.Contains(query, " ") {
		return []string{"%" + query + "%"}
	}

	parts := strings.Fields(query)
	patterns := make([]string, 0, len(parts))

	for _, part := range parts {
		part = strings.TrimSpace(part)
		if part != "" {
			patterns = append(patterns, "%"+part+"%")
		}
	}

	if len(patterns) == 0 {
		return []string{"%" + query + "%"}
	}

	return patterns
}

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, " · ")
}

func formatSearchDate(value time.Time) string {
	if value.IsZero() {
		return ""
	}

	return value.Format("02.01.2006 15:04")
}

func truncateSearchText(value string, maxLength int) string {
	value = strings.TrimSpace(value)

	if maxLength <= 0 {
		return value
	}

	runes := []rune(value)
	if len(runes) <= maxLength {
		return value
	}

	return strings.TrimSpace(string(runes[:maxLength])) + "…"
}