package profile

import (
	"errors"
	"fmt"
	"sync"
	"time"

	"github.com/safing/portbase/database/record"
	"github.com/safing/portmaster/profile/binmeta"
)

// MergeProfiles merges multiple profiles into a new one.
// The new profile is saved and returned.
// Only the icon and fingerprints are inherited from other profiles.
// All other information is taken only from the primary profile.
func MergeProfiles(name string, primary *Profile, secondaries ...*Profile) (newProfile *Profile, err error) {
	if primary == nil || len(secondaries) == 0 {
		return nil, errors.New("must supply both a primary and at least one secondary profile for merging")
	}

	// Fill info from primary profile.
	nowUnix := time.Now().Unix()
	newProfile = &Profile{
		Base:                record.Base{},
		RWMutex:             sync.RWMutex{},
		ID:                  "", // Omit ID to derive it from the new fingerprints.
		Source:              primary.Source,
		Name:                name,
		Description:         primary.Description,
		Homepage:            primary.Homepage,
		UsePresentationPath: false, // Disable presentation path.
		Config:              primary.Config,
		Created:             nowUnix,
	}

	// Fall back to name of primary profile, if none is set.
	if newProfile.Name == "" {
		newProfile.Name = primary.Name
	}

	// If any profile was edited, set LastEdited to now.
	if primary.LastEdited > 0 {
		newProfile.LastEdited = nowUnix
	} else {
		for _, sp := range secondaries {
			if sp.LastEdited > 0 {
				newProfile.LastEdited = nowUnix
				break
			}
		}
	}

	// Collect all icons.
	newProfile.Icons = make([]binmeta.Icon, 0, len(secondaries)+1) // Guess the needed space.
	newProfile.Icons = append(newProfile.Icons, primary.Icons...)
	for _, sp := range secondaries {
		newProfile.Icons = append(newProfile.Icons, sp.Icons...)
	}
	newProfile.Icons = binmeta.SortAndCompactIcons(newProfile.Icons)

	// Collect all fingerprints.
	newProfile.Fingerprints = make([]Fingerprint, 0, len(primary.Fingerprints)+len(secondaries)) // Guess the needed space.
	newProfile.Fingerprints = addFingerprints(newProfile.Fingerprints, primary.Fingerprints, primary.ScopedID())
	for _, sp := range secondaries {
		newProfile.Fingerprints = addFingerprints(newProfile.Fingerprints, sp.Fingerprints, sp.ScopedID())
	}
	newProfile.Fingerprints = sortAndCompactFingerprints(newProfile.Fingerprints)

	// Save new profile.
	newProfile = New(newProfile)
	if err := newProfile.Save(); err != nil {
		return nil, fmt.Errorf("failed to save merged profile: %w", err)
	}

	// Delete all previous profiles.
	if err := primary.delete(); err != nil {
		return nil, fmt.Errorf("failed to delete primary profile %s: %w", primary.ScopedID(), err)
	}
	module.TriggerEvent(MigratedEvent, []string{primary.ScopedID(), newProfile.ScopedID()})
	for _, sp := range secondaries {
		if err := sp.delete(); err != nil {
			return nil, fmt.Errorf("failed to delete secondary profile %s: %w", sp.ScopedID(), err)
		}
		module.TriggerEvent(MigratedEvent, []string{sp.ScopedID(), newProfile.ScopedID()})
	}

	return newProfile, nil
}

func addFingerprints(existing, add []Fingerprint, from string) []Fingerprint {
	// Copy all fingerprints and add the they are from.
	for _, addFP := range add {
		existing = append(existing, Fingerprint{
			Type:       addFP.Type,
			Key:        addFP.Key,
			Operation:  addFP.Operation,
			Value:      addFP.Value,
			MergedFrom: from,
		})
	}

	return existing
}