// Package store contains primitives for representing and changing the
// osbuild-composer state.
package store

import (
	"bytes"
	"crypto/sha1"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/osbuild/osbuild-composer/internal/blueprint"
	"github.com/osbuild/osbuild-composer/internal/distro"
	"github.com/osbuild/osbuild-composer/internal/pipeline"
	"github.com/osbuild/osbuild-composer/internal/rpmmd"
	"github.com/osbuild/osbuild-composer/internal/target"

	"github.com/google/uuid"
)

// A Store contains all the persistent state of osbuild-composer, and is serialized
// on every change, and deserialized on start.
type Store struct {
	Blueprints        map[string]blueprint.Blueprint         `json:"blueprints"`
	Workspace         map[string]blueprint.Blueprint         `json:"workspace"`
	Composes          map[uuid.UUID]Compose                  `json:"composes"`
	Sources           map[string]SourceConfig                `json:"sources"`
	BlueprintsChanges map[string]map[string]blueprint.Change `json:"changes"`

	mu           sync.RWMutex // protects all fields
	pendingJobs  chan Job
	stateChannel chan []byte
	distro       distro.Distro
	stateDir     *string
}

// A Compose represent the task of building one image. It contains all the information
// necessary to generate the inputs for the job, as well as the job's state.
type Compose struct {
	QueueStatus string               `json:"queue_status"`
	Blueprint   *blueprint.Blueprint `json:"blueprint"`
	OutputType  string               `json:"output-type"`
	Pipeline    *pipeline.Pipeline   `json:"pipeline"`
	Targets     []*target.Target     `json:"targets"`
	JobCreated  time.Time            `json:"job_created"`
	JobStarted  time.Time            `json:"job_started"`
	JobFinished time.Time            `json:"job_finished"`
	Image       *Image               `json:"image"`
}

// A Job contains the information about a compose a worker needs to process it.
type Job struct {
	ComposeID  uuid.UUID
	Distro     string
	Pipeline   *pipeline.Pipeline
	Targets    []*target.Target
	OutputType string
}

// An Image represents the image resulting from a compose.
type Image struct {
	Path string
	Mime string
	Size int64
}

type SourceConfig struct {
	Name     string `json:"name"`
	Type     string `json:"type"`
	URL      string `json:"url"`
	CheckGPG bool   `json:"check_gpg"`
	CheckSSL bool   `json:"check_ssl"`
	System   bool   `json:"system"`
}

type NotFoundError struct {
	message string
}

func (e *NotFoundError) Error() string {
	return e.message
}

type NotPendingError struct {
	message string
}

func (e *NotPendingError) Error() string {
	return e.message
}

type NotRunningError struct {
	message string
}

func (e *NotRunningError) Error() string {
	return e.message
}

type InvalidRequestError struct {
	message string
}

func (e *InvalidRequestError) Error() string {
	return e.message
}

func New(stateDir *string, distro distro.Distro) *Store {
	var s Store

	if stateDir != nil {
		err := os.Mkdir(*stateDir+"/"+"outputs", 0700)
		if err != nil && !os.IsExist(err) {
			log.Fatalf("cannot create output directory")
		}

		stateFile := *stateDir + "/state.json"
		state, err := ioutil.ReadFile(stateFile)

		if err == nil {
			err := json.Unmarshal(state, &s)
			if err != nil {
				log.Fatalf("invalid initial state: %v", err)
			}
		} else if !os.IsNotExist(err) {
			log.Fatalf("cannot read state: %v", err)
		}

		s.stateChannel = make(chan []byte, 128)

		go func() {
			for {
				err := writeFileAtomically(stateFile, <-s.stateChannel, 0600)
				if err != nil {
					log.Fatalf("cannot write state: %v", err)
				}
			}
		}()
	}

	s.pendingJobs = make(chan Job, 200)
	s.distro = distro
	s.stateDir = stateDir

	if s.Blueprints == nil {
		s.Blueprints = make(map[string]blueprint.Blueprint)
	}
	if s.Workspace == nil {
		s.Workspace = make(map[string]blueprint.Blueprint)
	}
	if s.Composes == nil {
		s.Composes = make(map[uuid.UUID]Compose)
	} else {
		for composeID, compose := range s.Composes {
			switch compose.QueueStatus {
			case "RUNNING":
				// We do not support resuming an in-flight build
				compose.QueueStatus = "FAILED"
				s.Composes[composeID] = compose
			case "WAITING":
				// Push waiting composes back into the pending jobs queue
				s.pendingJobs <- Job{
					ComposeID:  composeID,
					Distro:     s.distro.Name(),
					Pipeline:   compose.Pipeline,
					Targets:    compose.Targets,
					OutputType: compose.OutputType,
				}
			}
		}
	}
	if s.Sources == nil {
		s.Sources = make(map[string]SourceConfig)
	}
	if s.BlueprintsChanges == nil {
		s.BlueprintsChanges = make(map[string]map[string]blueprint.Change)
	}

	return &s
}

func writeFileAtomically(filename string, data []byte, mode os.FileMode) error {
	dir, name := filepath.Dir(filename), filepath.Base(filename)

	tmpfile, err := ioutil.TempFile(dir, name+"-*.tmp")
	if err != nil {
		return err
	}

	_, err = tmpfile.Write(data)
	if err != nil {
		os.Remove(tmpfile.Name())
		return err
	}

	err = tmpfile.Chmod(mode)
	if err != nil {
		return err
	}

	err = tmpfile.Close()
	if err != nil {
		os.Remove(tmpfile.Name())
		return err
	}

	err = os.Rename(tmpfile.Name(), filename)
	if err != nil {
		os.Remove(tmpfile.Name())
		return err
	}

	return nil
}

func (s *Store) change(f func() error) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	result := f()

	if s.stateChannel != nil {
		serialized, err := json.Marshal(s)
		if err != nil {
			// we ought to know all types that go into the store
			panic(err)
		}

		s.stateChannel <- serialized
	}
	return result
}

func (s *Store) ListBlueprints() []string {
	s.mu.RLock()
	defer s.mu.RUnlock()

	names := make([]string, 0, len(s.Blueprints))
	for name := range s.Blueprints {
		names = append(names, name)
	}
	sort.Strings(names)

	return names
}

func (s *Store) GetBlueprint(name string) (*blueprint.Blueprint, bool) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	bp, inWorkspace := s.Workspace[name]
	if !inWorkspace {
		var ok bool
		bp, ok = s.Blueprints[name]
		if !ok {
			return nil, false
		}
	}

	// cockpit-composer cannot deal with missing "packages" or "modules"
	if bp.Packages == nil {
		bp.Packages = []blueprint.Package{}
	}
	if bp.Modules == nil {
		bp.Modules = []blueprint.Package{}
	}
	if bp.Groups == nil {
		bp.Groups = []blueprint.Group{}
	}
	if bp.Version == "" {
		bp.Version = "0.0.0"
	}

	return &bp, inWorkspace
}

func (s *Store) GetBlueprintCommitted(name string) *blueprint.Blueprint {
	s.mu.RLock()
	defer s.mu.RUnlock()

	bp, ok := s.Blueprints[name]
	if !ok {
		return nil
	}

	// cockpit-composer cannot deal with missing "packages" or "modules"
	if bp.Packages == nil {
		bp.Packages = []blueprint.Package{}
	}
	if bp.Modules == nil {
		bp.Modules = []blueprint.Package{}
	}
	if bp.Groups == nil {
		bp.Groups = []blueprint.Group{}
	}
	if bp.Version == "" {
		bp.Version = "0.0.0"
	}

	return &bp
}

func (s *Store) GetBlueprintChange(name string, commit string) *blueprint.Change {
	s.mu.RLock()
	defer s.mu.RUnlock()

	change, ok := s.BlueprintsChanges[name][commit]
	if !ok {
		return nil
	}
	return &change
}

func (s *Store) GetBlueprintChanges(name string) []blueprint.Change {
	s.mu.RLock()
	defer s.mu.RUnlock()

	var changes []blueprint.Change

	for _, change := range s.BlueprintsChanges[name] {
		changes = append(changes, change)
	}

	return changes
}

func bumpVersion(str string) string {
	v := [3]uint64{}
	fields := strings.SplitN(str, ".", 3)
	for i := 0; i < len(fields); i++ {
		if n, err := strconv.ParseUint(fields[i], 10, 64); err == nil {
			v[i] = n
		} else {
			// don't touch strings with invalid versions
			return str
		}
	}

	return fmt.Sprintf("%d.%d.%d", v[0], v[1], v[2]+1)
}

func (s *Store) PushBlueprint(bp blueprint.Blueprint, commitMsg string) {
	s.change(func() error {
		hash := sha1.New()
		// Hash timestamp to create unique hash
		hash.Write([]byte(time.Now().String()))
		// Get hash as a byte slice
		commitBytes := hash.Sum(nil)
		// Get hash as a hex string
		commit := hex.EncodeToString(commitBytes)
		timestamp := time.Now().Format("2006-01-02T15:04:05Z")
		change := blueprint.Change{
			Commit:    commit,
			Message:   commitMsg,
			Timestamp: timestamp,
			Blueprint: bp,
		}

		delete(s.Workspace, bp.Name)
		if s.BlueprintsChanges[bp.Name] == nil {
			s.BlueprintsChanges[bp.Name] = make(map[string]blueprint.Change)
		}
		s.BlueprintsChanges[bp.Name][commit] = change

		if old, ok := s.Blueprints[bp.Name]; ok {
			if bp.Version == "" || bp.Version == old.Version {
				bp.Version = bumpVersion(old.Version)
			}
		}
		s.Blueprints[bp.Name] = bp
		return nil
	})
}

func (s *Store) PushBlueprintToWorkspace(bp blueprint.Blueprint) {
	s.change(func() error {
		s.Workspace[bp.Name] = bp
		return nil
	})
}

func (s *Store) DeleteBlueprint(name string) {
	s.change(func() error {
		delete(s.Workspace, name)
		delete(s.Blueprints, name)
		return nil
	})
}

func (s *Store) DeleteBlueprintFromWorkspace(name string) {
	s.change(func() error {
		delete(s.Workspace, name)
		return nil
	})
}

func (s *Store) GetCompose(id uuid.UUID) (Compose, bool) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	compose, exists := s.Composes[id]
	return compose, exists
}

func (s *Store) GetAllComposes() map[uuid.UUID]Compose {
	s.mu.RLock()
	defer s.mu.RUnlock()

	composes := make(map[uuid.UUID]Compose)

	for id, compose := range s.Composes {
		newCompose := compose
		newCompose.Targets = []*target.Target{}

		for _, t := range compose.Targets {
			newTarget := *t
			newCompose.Targets = append(newCompose.Targets, &newTarget)
		}

		newBlueprint := *compose.Blueprint
		newCompose.Blueprint = &newBlueprint

		composes[id] = newCompose
	}

	return composes
}

func (s *Store) GetComposeResult(id uuid.UUID) (io.ReadCloser, error) {
	if s.stateDir == nil {
		return ioutil.NopCloser(bytes.NewBuffer([]byte("{}"))), nil
	}
	return os.Open(*s.stateDir + "/outputs/" + id.String() + "/result.json")
}

func (s *Store) PushCompose(composeID uuid.UUID, bp *blueprint.Blueprint, checksums map[string]string, arch, composeType string, uploadTarget *target.Target) error {
	targets := []*target.Target{}

	if s.stateDir != nil {
		targets = append(targets, target.NewLocalTarget(
			&target.LocalTargetOptions{
				Location: *s.stateDir + "/outputs/" + composeID.String(),
			},
		))
	}

	if uploadTarget != nil {
		targets = append(targets, uploadTarget)
	}

	repos := []rpmmd.RepoConfig{}
	for _, source := range s.Sources {
		repos = append(repos, source.RepoConfig())
	}

	pipeline, err := s.distro.Pipeline(bp, repos, checksums, arch, composeType, 0)
	if err != nil {
		return err
	}
	s.change(func() error {
		s.Composes[composeID] = Compose{
			QueueStatus: "WAITING",
			Blueprint:   bp,
			Pipeline:    pipeline,
			OutputType:  composeType,
			Targets:     targets,
			JobCreated:  time.Now(),
		}
		return nil
	})
	s.pendingJobs <- Job{
		ComposeID:  composeID,
		Distro:     s.distro.Name(),
		Pipeline:   pipeline,
		Targets:    targets,
		OutputType: composeType,
	}

	return nil
}

func (s *Store) DeleteCompose(id uuid.UUID) error {
	return s.change(func() error {
		compose, exists := s.Composes[id]

		if !exists {
			return &NotFoundError{}
		}

		if compose.QueueStatus != "FINISHED" && compose.QueueStatus != "FAILED" {
			return &InvalidRequestError{fmt.Sprintf("Compose %s is not in FINISHED or FAILED.", id)}
		}

		delete(s.Composes, id)

		var err error
		if s.stateDir != nil {
			err = os.RemoveAll(*s.stateDir + "/outputs/" + id.String())
		}

		return err
	})
}

func (s *Store) PopCompose() Job {
	job := <-s.pendingJobs
	s.change(func() error {
		compose, exists := s.Composes[job.ComposeID]
		if !exists || compose.QueueStatus != "WAITING" {
			panic("Invalid job in queue.")
		}
		compose.JobStarted = time.Now()
		compose.QueueStatus = "RUNNING"
		for _, t := range compose.Targets {
			t.Status = "RUNNING"
		}
		s.Composes[job.ComposeID] = compose
		return nil
	})
	return job
}

func (s *Store) UpdateCompose(composeID uuid.UUID, status string, image *Image) error {
	return s.change(func() error {
		compose, exists := s.Composes[composeID]
		if !exists {
			return &NotFoundError{"compose does not exist"}
		}
		if compose.QueueStatus == "WAITING" {
			return &NotPendingError{"compose has not been popped"}
		}
		switch status {
		case "RUNNING":
			switch compose.QueueStatus {
			case "RUNNING":
			default:
				return &NotRunningError{"compose was not running"}
			}
		case "FINISHED", "FAILED":
			switch compose.QueueStatus {
			case "RUNNING":
				compose.JobFinished = time.Now()
			default:
				return &NotRunningError{"compose was not running"}
			}
			compose.QueueStatus = status
			for _, t := range compose.Targets {
				t.Status = status
			}

			if status == "FINISHED" {
				compose.Image = image
			}

			s.Composes[composeID] = compose
		default:
			return &InvalidRequestError{"invalid state transition"}
		}
		return nil
	})
}

func (s *Store) PushSource(source SourceConfig) {
	s.change(func() error {
		s.Sources[source.Name] = source
		return nil
	})
}

func (s *Store) DeleteSource(name string) {
	s.change(func() error {
		delete(s.Sources, name)
		return nil
	})
}

func (s *Store) ListSources() []string {
	s.mu.RLock()
	defer s.mu.RUnlock()
	names := make([]string, 0, len(s.Sources))
	for name := range s.Sources {
		names = append(names, name)
	}
	sort.Strings(names)

	return names
}

func (s *Store) GetSource(name string) *SourceConfig {
	s.mu.RLock()
	defer s.mu.RUnlock()

	source, ok := s.Sources[name]
	if !ok {
		return nil
	}
	return &source
}

func (s *Store) GetAllSources() map[string]SourceConfig {
	s.mu.RLock()
	defer s.mu.RUnlock()

	sources := make(map[string]SourceConfig)

	for k, v := range s.Sources {
		sources[k] = v
	}

	return sources
}

func NewSourceConfig(repo rpmmd.RepoConfig, system bool) SourceConfig {
	sc := SourceConfig{
		Name:     repo.Id,
		CheckGPG: true,
		CheckSSL: !repo.IgnoreSSL,
		System:   system,
	}

	if repo.BaseURL != "" {
		sc.URL = repo.BaseURL
		sc.Type = "yum-baseurl"
	} else if repo.Metalink != "" {
		sc.URL = repo.Metalink
		sc.Type = "yum-metalink"
	} else if repo.MirrorList != "" {
		sc.URL = repo.MirrorList
		sc.Type = "yum-mirrorlist"
	}

	return sc
}

func (s *SourceConfig) RepoConfig() rpmmd.RepoConfig {
	var repo rpmmd.RepoConfig

	repo.Name = s.Name
	repo.Id = s.Name
	repo.IgnoreSSL = !s.CheckSSL

	if s.Type == "yum-baseurl" {
		repo.BaseURL = s.URL
	} else if s.Type == "yum-metalink" {
		repo.Metalink = s.URL
	} else if s.Type == "yum-mirrorlist" {
		repo.MirrorList = s.URL
	}

	return repo
}