// Copyright (c) 2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package iam

import (
	"context"
	"fmt"
	"strconv"
	"strings"
	"time"

	"go.gearno.de/kit/pg"
	"go.probo.inc/probo/pkg/coredata"
	"go.probo.inc/probo/pkg/gid"
	"go.probo.inc/probo/pkg/page"
	"go.probo.inc/probo/pkg/safecsv"
)

type (
	scimProfileExportInfo struct {
		email    string
		fullName string
	}

	scimProfileExportLookup struct {
		byProfileID map[gid.GID]scimProfileExportInfo
		byUserName  map[string]scimProfileExportInfo
	}

	auditLogActorExportInfo struct {
		email string
		name  string
	}
)

var (
	auditLogExportCSVHeader = []string{
		"organization_name",
		"id",
		"created_at",
		"actor_type",
		"actor_id",
		"actor_email",
		"actor_name",
		"action",
		"resource_type",
		"resource_id",
	}

	scimEventExportCSVHeader = []string{
		"organization_name",
		"id",
		"created_at",
		"method",
		"path",
		"user_name",
		"email",
		"full_name",
		"status_code",
		"error_message",
		"ip_address",
	}

	auditLogExportOrderBy = page.OrderBy[coredata.AuditLogEntryOrderField]{
		Field:     coredata.AuditLogEntryOrderFieldCreatedAt,
		Direction: page.OrderDirectionAsc,
	}

	scimEventExportOrderBy = page.OrderBy[coredata.SCIMEventOrderField]{
		Field:     coredata.SCIMEventOrderFieldCreatedAt,
		Direction: page.OrderDirectionAsc,
	}
)

func (s *LogExportService) streamAuditLogCSV(
	ctx context.Context,
	conn pg.Querier,
	scope coredata.Scoper,
	organizationID gid.GID,
	organizationName string,
	filter *coredata.AuditLogEntryFilter,
	w *safecsv.Writer,
) error {
	if err := w.Write(auditLogExportCSVHeader); err != nil {
		return fmt.Errorf("cannot write audit log CSV header: %w", err)
	}

	return page.WalkAll(
		ctx,
		auditLogExportOrderBy,
		func(ctx context.Context, cursor *page.Cursor[coredata.AuditLogEntryOrderField]) (coredata.AuditLogEntries, error) {
			var logs coredata.AuditLogEntries
			if err := logs.LoadByOrganizationID(
				ctx,
				conn,
				scope,
				organizationID,
				cursor,
				filter,
			); err != nil {
				return nil, fmt.Errorf("cannot load audit log entries: %w", err)
			}

			return logs, nil
		},
		func(entries coredata.AuditLogEntries) error {
			actorsByID, err := loadAuditLogActorExportInfo(ctx, conn, entries)
			if err != nil {
				return err
			}

			for _, entry := range entries {
				if err := writeAuditLogEntryCSVRow(w, organizationName, entry, actorsByID[entry.ActorID]); err != nil {
					return fmt.Errorf("cannot write audit log CSV row: %w", err)
				}
			}

			w.Flush()

			if err := w.Error(); err != nil {
				return fmt.Errorf("cannot flush audit log CSV writer: %w", err)
			}

			return nil
		},
	)
}

func (s *LogExportService) streamSCIMEventCSV(
	ctx context.Context,
	conn pg.Querier,
	scope coredata.Scoper,
	organizationID gid.GID,
	organizationName string,
	filter *coredata.SCIMEventFilter,
	w *safecsv.Writer,
) error {
	if err := w.Write(scimEventExportCSVHeader); err != nil {
		return fmt.Errorf("cannot write SCIM event CSV header: %w", err)
	}

	return page.WalkAll(
		ctx,
		scimEventExportOrderBy,
		func(ctx context.Context, cursor *page.Cursor[coredata.SCIMEventOrderField]) (coredata.SCIMEvents, error) {
			var events coredata.SCIMEvents
			if err := events.LoadByOrganizationID(
				ctx,
				conn,
				scope,
				organizationID,
				cursor,
				filter,
			); err != nil {
				return nil, fmt.Errorf("cannot load SCIM events: %w", err)
			}

			return events, nil
		},
		func(events coredata.SCIMEvents) error {
			profileLookup, err := loadSCIMProfileExportInfo(ctx, conn, scope, events)
			if err != nil {
				return err
			}

			for _, event := range events {
				if err := writeSCIMEventCSVRow(w, organizationName, event, profileLookup); err != nil {
					return fmt.Errorf("cannot write SCIM event CSV row: %w", err)
				}
			}

			w.Flush()

			if err := w.Error(); err != nil {
				return fmt.Errorf("cannot flush SCIM event CSV writer: %w", err)
			}

			return nil
		},
	)
}

func writeAuditLogEntryCSVRow(
	w *safecsv.Writer,
	organizationName string,
	entry *coredata.AuditLogEntry,
	actor auditLogActorExportInfo,
) error {
	return w.Write([]string{
		organizationName,
		entry.ID.String(),
		entry.CreatedAt.Format(time.RFC3339),
		string(entry.ActorType),
		entry.ActorID.String(),
		actor.email,
		actor.name,
		entry.Action,
		entry.ResourceType,
		entry.ResourceID.String(),
	})
}

func writeSCIMEventCSVRow(
	w *safecsv.Writer,
	organizationName string,
	event *coredata.SCIMEvent,
	lookup scimProfileExportLookup,
) error {
	profile := lookup.forEvent(event)

	return w.Write([]string{
		organizationName,
		event.ID.String(),
		event.CreatedAt.Format(time.RFC3339),
		event.Method,
		event.Path,
		event.UserName,
		profile.email,
		profile.fullName,
		strconv.Itoa(event.StatusCode),
		stringPtrValue(event.ErrorMessage),
		event.IPAddress.String(),
	})
}

func loadAuditLogActorExportInfo(
	ctx context.Context,
	conn pg.Querier,
	entries coredata.AuditLogEntries,
) (map[gid.GID]auditLogActorExportInfo, error) {
	identityIDs := make([]gid.GID, 0)
	apiKeyIDs := make([]gid.GID, 0)

	for _, entry := range entries {
		switch entry.ActorType {
		case coredata.AuditLogActorTypeUser:
			identityIDs = append(identityIDs, entry.ActorID)
		case coredata.AuditLogActorTypeAPIKey:
			apiKeyIDs = append(apiKeyIDs, entry.ActorID)
		case coredata.AuditLogActorTypeSystem:
		default:
		}
	}

	result := make(map[gid.GID]auditLogActorExportInfo)

	var identities coredata.Identities
	if err := identities.LoadByIDs(ctx, conn, identityIDs); err != nil {
		return nil, fmt.Errorf("cannot load audit log actor identities: %w", err)
	}

	for _, identity := range identities {
		result[identity.ID] = auditLogActorExportInfo{
			email: identity.EmailAddress.String(),
			name:  identity.FullName,
		}
	}

	var apiKeys coredata.PersonalAPIKeys
	if err := apiKeys.LoadByIDs(ctx, conn, apiKeyIDs); err != nil {
		return nil, fmt.Errorf("cannot load audit log actor API keys: %w", err)
	}

	for _, apiKey := range apiKeys {
		result[apiKey.ID] = auditLogActorExportInfo{
			name: apiKey.Name,
		}
	}

	return result, nil
}

func loadSCIMProfileExportInfo(
	ctx context.Context,
	conn pg.Querier,
	scope coredata.Scoper,
	events coredata.SCIMEvents,
) (scimProfileExportLookup, error) {
	profileIDs := scimEventProfileIDs(events)
	if len(profileIDs) == 0 {
		return scimProfileExportLookup{
			byProfileID: map[gid.GID]scimProfileExportInfo{},
			byUserName:  map[string]scimProfileExportInfo{},
		}, nil
	}

	var profiles coredata.MembershipProfiles
	if err := profiles.LoadExistingByIDs(ctx, conn, scope, profileIDs); err != nil {
		return scimProfileExportLookup{}, fmt.Errorf("cannot load SCIM export profiles: %w", err)
	}

	identityIDs := make([]gid.GID, 0, len(profiles))
	for _, profile := range profiles {
		identityIDs = append(identityIDs, profile.IdentityID)
	}

	var identities coredata.Identities
	if err := identities.LoadByIDs(ctx, conn, identityIDs); err != nil {
		return scimProfileExportLookup{}, fmt.Errorf("cannot load SCIM profile identity emails: %w", err)
	}

	emailByIdentityID := make(map[gid.GID]string, len(identities))
	for _, identity := range identities {
		emailByIdentityID[identity.ID] = identity.EmailAddress.String()
	}

	lookup := scimProfileExportLookup{
		byProfileID: make(map[gid.GID]scimProfileExportInfo, len(profiles)),
		byUserName:  make(map[string]scimProfileExportInfo, len(profiles)),
	}
	for _, profile := range profiles {
		info := scimProfileExportInfo{
			email:    emailByIdentityID[profile.IdentityID],
			fullName: profileFullName(profile),
		}

		lookup.byProfileID[profile.ID] = info

		if profile.UserName != nil {
			lookup.byUserName[strings.ToLower(*profile.UserName)] = info
		}
	}

	return lookup, nil
}

func (l scimProfileExportLookup) forEvent(event *coredata.SCIMEvent) scimProfileExportInfo {
	if profileID, ok := scimProfileIDFromEventPath(event.Path); ok {
		if info, ok := l.byProfileID[profileID]; ok {
			return info
		}
	}

	if event.UserName != "" {
		return l.byUserName[strings.ToLower(event.UserName)]
	}

	return scimProfileExportInfo{}
}

const scimUsersResourcePathPrefix = "/Users/"

func scimProfileIDFromEventPath(path string) (gid.GID, bool) {
	if !strings.HasPrefix(path, scimUsersResourcePathPrefix) {
		return gid.GID{}, false
	}

	rest := strings.TrimPrefix(path, scimUsersResourcePathPrefix)
	if rest == "" {
		return gid.GID{}, false
	}

	idPart, _, _ := strings.Cut(rest, "?")

	idPart, _, _ = strings.Cut(idPart, "/")
	if idPart == "" {
		return gid.GID{}, false
	}

	profileID, err := gid.ParseGID(idPart)
	if err != nil {
		return gid.GID{}, false
	}

	return profileID, true
}

func scimEventProfileIDs(events coredata.SCIMEvents) []gid.GID {
	seen := gid.NewSet()

	for _, event := range events {
		profileID, ok := scimProfileIDFromEventPath(event.Path)
		if !ok {
			continue
		}

		seen[profileID] = struct{}{}
	}

	profileIDs := make([]gid.GID, 0, len(seen))
	for profileID := range seen {
		profileIDs = append(profileIDs, profileID)
	}

	return profileIDs
}

func profileFullName(profile *coredata.MembershipProfile) string {
	if profile.FormattedName != nil && *profile.FormattedName != "" {
		return *profile.FormattedName
	}

	return profile.FullName
}

func stringPtrValue(value *string) string {
	if value == nil {
		return ""
	}

	return *value
}