package api

import (
	"context"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"

	"bat-api/internal/backendrpc"
)

// Backend is the subset of daemon RPC used by bat-api.
//
// Call order for discovery (per plan review):
//  1. daemon.status
//  2. daemon.doctor
//  3. catalog.status / resource.manifest (and resource.state as needed)
type Backend interface {
	DaemonStatus(ctx context.Context) (*backendrpc.DaemonStatusReport, error)
	DaemonDoctor(ctx context.Context) (*backendrpc.DoctorReport, error)
	ResourceState(ctx context.Context) (*backendrpc.ResourceState, error)
	CatalogStatus(ctx context.Context) (json.RawMessage, error)
	ResourceManifest(ctx context.Context, offset int, limit int) (*backendrpc.ResourceManifestPage, error)
}

// ControlBackend is the explicitly allowlisted mutation subset exposed through
// the authenticated bat-api admin control surface.
//
// It intentionally does not include daemon.stop, cleanup, or generic RPC calls.
// Restart is forwarded only to Rust's lifecycle RPC; Go never execs bat itself.
type ControlBackend interface {
	DaemonRestart(ctx context.Context) (*backendrpc.Ack, error)
	DaemonReload(ctx context.Context) (*backendrpc.Ack, error)
	DaemonRefresh(ctx context.Context, force bool) (*backendrpc.Ack, error)
	ResourceSync(ctx context.Context, force bool) (*backendrpc.TaskAccepted, error)
	ResourceVerify(ctx context.Context) (*backendrpc.TaskAccepted, error)
	ResourceRepair(ctx context.Context) (*backendrpc.TaskAccepted, error)
	CatalogRefresh(ctx context.Context, force bool) (*backendrpc.TaskAccepted, error)
}

// DaemonLogsBackend exposes the Rust daemon log tail for an authenticated
// dashboard. It remains read-only and never opens log files from Go.
type DaemonLogsBackend interface {
	DaemonLogs(ctx context.Context, tail int) (*backendrpc.LogsReport, error)
}

// TaskBackend exposes Rust-owned async task state to the dashboard. Go only
// forwards read/cancel requests and does not create generic tasks.
type TaskBackend interface {
	TaskList(ctx context.Context) (*backendrpc.TaskList, error)
	TaskStatus(ctx context.Context, taskID string) (*backendrpc.TaskRecord, error)
	TaskLogs(ctx context.Context, taskID string) (*backendrpc.TaskLogs, error)
	TaskCancel(ctx context.Context, taskID string) (*backendrpc.TaskCancelResult, error)
}

// ParseBackend exposes existing Rust TextUnit index queries to the dashboard.
// It is read-only and does not expand parser coverage.
type ParseBackend interface {
	ParseStatus(ctx context.Context) (json.RawMessage, error)
	ParseTextUnits(ctx context.Context, query backendrpc.TextUnitQueryParams) (json.RawMessage, error)
	ParseErrors(ctx context.Context, query backendrpc.TextUnitQueryParams) (json.RawMessage, error)
}

// ScheduleBackend exposes the Rust-owned schedule store to an authenticated
// dashboard. The JSON result remains Rust's report shape so the API does not
// duplicate schedule state or invent a second schema.
type ScheduleBackend interface {
	ScheduleList(ctx context.Context, params backendrpc.ScheduleListParams) (json.RawMessage, error)
	ScheduleAdd(ctx context.Context, params backendrpc.ScheduleMutationParams) (json.RawMessage, error)
	ScheduleUpdate(ctx context.Context, params backendrpc.ScheduleMutationParams) (json.RawMessage, error)
	ScheduleRemove(ctx context.Context, params backendrpc.ScheduleMutationParams) (json.RawMessage, error)
	ScheduleRun(ctx context.Context, params backendrpc.ScheduleRunParams) (json.RawMessage, error)
}

// TranslationBackend exposes the narrow provider-worker state mutation used
// by the dashboard. It does not create arbitrary translation jobs.
type TranslationBackend interface {
	TranslationTaskUpdate(ctx context.Context, params backendrpc.TranslationTaskUpdateParams) (json.RawMessage, error)
	TranslationTasks(ctx context.Context, params backendrpc.TranslationTaskListParams) (json.RawMessage, error)
	TranslationHandoff(ctx context.Context) (json.RawMessage, error)
	TranslationWorkerRun(ctx context.Context, params backendrpc.TranslationWorkerRunParams) (*backendrpc.TranslationWorkerRunResult, error)
	TranslationProofread(ctx context.Context) (json.RawMessage, error)
}

// TranslationMemoryBackend exposes the Rust-owned Translation Memory query and
// explicit confirmation operations. Go forwards typed requests and responses
// but never opens or mutates the TM database itself.
type TranslationMemoryBackend interface {
	TranslationMemorySummary(ctx context.Context, params backendrpc.TranslationMemorySummaryParams) (*backendrpc.TranslationMemorySummaryReport, error)
	TranslationMemoryQuery(ctx context.Context, params backendrpc.TranslationMemoryQueryParams) (*backendrpc.TranslationMemoryQueryReport, error)
	TranslationMemoryConfirm(ctx context.Context, params backendrpc.TranslationMemoryConfirmParams) (*backendrpc.TranslationMemoryConfirmReport, error)
}

// LocalizedBackend exposes localized release status and the explicit
// publish/rollback controls used by the authenticated dashboard.
type LocalizedBackend interface {
	LocalizedStatus(ctx context.Context) (json.RawMessage, error)
	LocalizedPublish(ctx context.Context, params backendrpc.LocalizedPublishParams) (json.RawMessage, error)
	LocalizedRollback(ctx context.Context, params backendrpc.LocalizedRollbackParams) (json.RawMessage, error)
}

// RPCClient adapts *backendrpc.Client to Backend.
type RPCClient struct {
	Client *backendrpc.Client
}

func (r RPCClient) DaemonStatus(ctx context.Context) (*backendrpc.DaemonStatusReport, error) {
	return r.Client.DaemonStatus(ctx)
}
func (r RPCClient) DaemonDoctor(ctx context.Context) (*backendrpc.DoctorReport, error) {
	return r.Client.DaemonDoctor(ctx)
}
func (r RPCClient) ResourceState(ctx context.Context) (*backendrpc.ResourceState, error) {
	return r.Client.ResourceState(ctx)
}
func (r RPCClient) CatalogStatus(ctx context.Context) (json.RawMessage, error) {
	return r.Client.CatalogStatus(ctx)
}
func (r RPCClient) ResourceManifest(ctx context.Context, offset int, limit int) (*backendrpc.ResourceManifestPage, error) {
	return r.Client.ResourceManifest(ctx, offset, limit)
}
func (r RPCClient) DaemonRestart(ctx context.Context) (*backendrpc.Ack, error) {
	return r.Client.DaemonRestart(ctx)
}
func (r RPCClient) DaemonReload(ctx context.Context) (*backendrpc.Ack, error) {
	return r.Client.DaemonReload(ctx)
}
func (r RPCClient) DaemonRefresh(ctx context.Context, force bool) (*backendrpc.Ack, error) {
	return r.Client.DaemonRefresh(ctx, force)
}
func (r RPCClient) DaemonLogs(ctx context.Context, tail int) (*backendrpc.LogsReport, error) {
	return r.Client.DaemonLogs(ctx, tail)
}
func (r RPCClient) ResourceSync(ctx context.Context, force bool) (*backendrpc.TaskAccepted, error) {
	return r.Client.ResourceSync(ctx, force)
}
func (r RPCClient) ResourceVerify(ctx context.Context) (*backendrpc.TaskAccepted, error) {
	return r.Client.ResourceVerify(ctx)
}
func (r RPCClient) ResourceRepair(ctx context.Context) (*backendrpc.TaskAccepted, error) {
	return r.Client.ResourceRepair(ctx)
}
func (r RPCClient) CatalogRefresh(ctx context.Context, force bool) (*backendrpc.TaskAccepted, error) {
	return r.Client.CatalogRefresh(ctx, force)
}
func (r RPCClient) TaskList(ctx context.Context) (*backendrpc.TaskList, error) {
	return r.Client.TaskList(ctx)
}
func (r RPCClient) TaskStatus(ctx context.Context, taskID string) (*backendrpc.TaskRecord, error) {
	return r.Client.TaskStatus(ctx, taskID)
}
func (r RPCClient) TaskLogs(ctx context.Context, taskID string) (*backendrpc.TaskLogs, error) {
	return r.Client.TaskLogs(ctx, taskID)
}
func (r RPCClient) TaskCancel(ctx context.Context, taskID string) (*backendrpc.TaskCancelResult, error) {
	return r.Client.TaskCancel(ctx, taskID)
}
func (r RPCClient) ScheduleList(ctx context.Context, params backendrpc.ScheduleListParams) (json.RawMessage, error) {
	return r.Client.ScheduleListFiltered(ctx, params)
}
func (r RPCClient) ScheduleAdd(ctx context.Context, params backendrpc.ScheduleMutationParams) (json.RawMessage, error) {
	return r.Client.ScheduleAdd(ctx, params)
}
func (r RPCClient) ScheduleUpdate(ctx context.Context, params backendrpc.ScheduleMutationParams) (json.RawMessage, error) {
	return r.Client.ScheduleUpdate(ctx, params)
}
func (r RPCClient) ScheduleRemove(ctx context.Context, params backendrpc.ScheduleMutationParams) (json.RawMessage, error) {
	return r.Client.ScheduleRemove(ctx, params)
}
func (r RPCClient) ScheduleRun(ctx context.Context, params backendrpc.ScheduleRunParams) (json.RawMessage, error) {
	return r.Client.ScheduleRun(ctx, params)
}
func (r RPCClient) TranslationTaskUpdate(ctx context.Context, params backendrpc.TranslationTaskUpdateParams) (json.RawMessage, error) {
	return r.Client.TranslationTaskUpdate(ctx, params)
}

func (r RPCClient) TranslationTasks(ctx context.Context, params backendrpc.TranslationTaskListParams) (json.RawMessage, error) {
	return r.Client.TranslationTasks(ctx, params)
}

func (r RPCClient) TranslationHandoff(ctx context.Context) (json.RawMessage, error) {
	return r.Client.TranslationHandoff(ctx)
}

func (r RPCClient) TranslationWorkerRun(ctx context.Context, params backendrpc.TranslationWorkerRunParams) (*backendrpc.TranslationWorkerRunResult, error) {
	return r.Client.TranslationWorkerRun(ctx, params)
}

func (r RPCClient) TranslationProofread(ctx context.Context) (json.RawMessage, error) {
	return r.Client.TranslationProofread(ctx)
}

func (r RPCClient) TranslationMemorySummary(ctx context.Context, params backendrpc.TranslationMemorySummaryParams) (*backendrpc.TranslationMemorySummaryReport, error) {
	return r.Client.TranslationMemorySummary(ctx, params)
}

func (r RPCClient) TranslationMemoryQuery(ctx context.Context, params backendrpc.TranslationMemoryQueryParams) (*backendrpc.TranslationMemoryQueryReport, error) {
	return r.Client.TranslationMemoryQuery(ctx, params)
}

func (r RPCClient) TranslationMemoryConfirm(ctx context.Context, params backendrpc.TranslationMemoryConfirmParams) (*backendrpc.TranslationMemoryConfirmReport, error) {
	return r.Client.TranslationMemoryConfirm(ctx, params)
}

func (r RPCClient) LocalizedStatus(ctx context.Context) (json.RawMessage, error) {
	return r.Client.LocalizedStatus(ctx)
}

func (r RPCClient) LocalizedPublish(ctx context.Context, params backendrpc.LocalizedPublishParams) (json.RawMessage, error) {
	return r.Client.LocalizedPublish(ctx, params)
}

func (r RPCClient) LocalizedRollback(ctx context.Context, params backendrpc.LocalizedRollbackParams) (json.RawMessage, error) {
	return r.Client.LocalizedRollback(ctx, params)
}

func (r RPCClient) ParseStatus(ctx context.Context) (json.RawMessage, error) {
	return r.Client.ParseStatus(ctx)
}
func (r RPCClient) ParseTextUnits(ctx context.Context, query backendrpc.TextUnitQueryParams) (json.RawMessage, error) {
	return r.Client.ParseTextUnits(ctx, query)
}
func (r RPCClient) ParseErrors(ctx context.Context, query backendrpc.TextUnitQueryParams) (json.RawMessage, error) {
	return r.Client.ParseErrors(ctx, query)
}
func (r RPCClient) UnityFSPatchTextAsset(ctx context.Context, params backendrpc.UnityFSTextAssetPatchParams) (json.RawMessage, error) {
	return r.Client.UnityFSPatchTextAsset(ctx, params)
}
func (r RPCClient) UnityFSPatchStringField(ctx context.Context, params backendrpc.UnityFSStringFieldPatchParams) (json.RawMessage, error) {
	return r.Client.UnityFSPatchStringField(ctx, params)
}
func (r RPCClient) UnityFSPatchField(ctx context.Context, params backendrpc.UnityFSFieldPatchParams) (json.RawMessage, error) {
	return r.Client.UnityFSPatchField(ctx, params)
}

// DiscoverResult is the outcome of talking to the bat daemon.
type DiscoverResult struct {
	RPCAvailable  bool
	DoctorHealthy *bool
	Status        *backendrpc.DaemonStatusReport
	Doctor        *backendrpc.DoctorReport
	Snapshot      *SnapshotSummary
	ResourceRoot  string
	Index         *ReleaseIndex
	Warnings      []string
}

// DiscoverAndIndex contacts the daemon (status first, then doctor) and builds
// a release index from paginated resource.manifest plus on-disk checks.
//
// If resourceRootOverride is non-empty, it wins over RPC-reported roots after
// RPC health probes (still preferred for production to call status/doctor).
func DiscoverAndIndex(ctx context.Context, backend Backend, resourceRootOverride string) (*DiscoverResult, error) {
	out := &DiscoverResult{}
	if backend == nil {
		if resourceRootOverride == "" {
			out.Index = &ReleaseIndex{Source: "empty", byRel: map[string]int{}}
			return out, nil
		}
		idx, err := LoadIndexFromResourceRoot(resourceRootOverride)
		if err != nil {
			return nil, err
		}
		out.ResourceRoot = idx.ResourceRoot
		out.Index = idx
		return out, nil
	}

	// 1) daemon.status first
	status, err := backend.DaemonStatus(ctx)
	if err != nil {
		out.Warnings = append(out.Warnings, fmt.Sprintf("daemon.status: %v", err))
		if resourceRootOverride != "" {
			idx, loadErr := LoadIndexFromResourceRoot(resourceRootOverride)
			if loadErr != nil {
				return out, fmt.Errorf("daemon.status failed (%v) and resource-root load failed: %w", err, loadErr)
			}
			out.ResourceRoot = idx.ResourceRoot
			out.Index = idx
			return out, nil
		}
		out.Index = &ReleaseIndex{Source: "empty", byRel: map[string]int{}}
		return out, nil
	}
	out.RPCAvailable = true
	out.Status = status

	// 2) daemon.doctor second
	doctor, err := backend.DaemonDoctor(ctx)
	if err != nil {
		out.Warnings = append(out.Warnings, fmt.Sprintf("daemon.doctor: %v", err))
	} else {
		out.Doctor = doctor
		h := doctor.Healthy
		out.DoctorHealthy = &h
	}

	// Catalog / resource discovery
	var snapshot *SnapshotSummary
	var resourceRoot string
	catalogAvailabilityKnown := false
	catalogAvailable := false

	if raw, err := backend.CatalogStatus(ctx); err != nil {
		out.Warnings = append(out.Warnings, fmt.Sprintf("catalog.status: %v", err))
	} else {
		catalogAvailable, catalogAvailabilityKnown = parseCatalogAvailability(raw)
		snap, root, ok := parseCatalogStatus(raw)
		if ok {
			snapshot = snap
			resourceRoot = root
		}
	}
	if catalogAvailabilityKnown && !catalogAvailable {
		return emptyRPCResult(out, snapshot, "catalog.status available=false; no published release"), nil
	}

	if resourceRoot == "" {
		if state, err := backend.ResourceState(ctx); err != nil {
			out.Warnings = append(out.Warnings, fmt.Sprintf("resource.state: %v", err))
		} else if state.ResourceOutputRoot != nil && *state.ResourceOutputRoot != "" {
			// Prefer published current under output root when catalog root missing.
			candidate := filepath.Join(*state.ResourceOutputRoot, "current")
			resourceRoot = candidate
		}
	}

	if resourceRootOverride != "" {
		resourceRoot = resourceRootOverride
	}
	if resourceRoot == "" {
		out.Snapshot = snapshot
		out.Index = &ReleaseIndex{
			Source:        "rpc",
			RPCAvailable:  true,
			DoctorHealthy: out.DoctorHealthy,
			Snapshot:      snapshot,
			byRel:         map[string]int{},
		}
		out.Warnings = append(out.Warnings, "no resource root from RPC; set --resource-root or publish a version")
		return out, nil
	}

	if resourceRootOverride == "" {
		info, statErr := os.Stat(resourceRoot)
		if statErr != nil || !info.IsDir() {
			warning := fmt.Sprintf("published resource root is unavailable: %s", resourceRoot)
			if statErr != nil {
				warning = fmt.Sprintf("%s (%v)", warning, statErr)
			} else {
				warning = fmt.Sprintf("%s (not a directory)", warning)
			}
			return emptyRPCResult(out, snapshot, warning), nil
		}
	}

	entries, manifestVersion, rootFromManifest, err := fetchAllManifestEntries(ctx, backend)
	if err != nil {
		out.Warnings = append(out.Warnings, fmt.Sprintf("resource.manifest: %v", err))
		// Fallback: load local manifest file under root.
		idx, loadErr := LoadIndexFromResourceRoot(resourceRoot)
		if loadErr != nil {
			if resourceRootOverride == "" {
				return emptyRPCResult(
					out,
					snapshot,
					fmt.Sprintf("published release cannot be indexed: %v", loadErr),
				), nil
			}
			return out, fmt.Errorf("manifest RPC and local load failed: rpc=%v local=%w", err, loadErr)
		}
		idx.Source = "rpc+local_manifest"
		idx.RPCAvailable = true
		idx.DoctorHealthy = out.DoctorHealthy
		if snapshot != nil {
			idx.Snapshot = snapshot
		}
		out.ResourceRoot = idx.ResourceRoot
		out.Snapshot = idx.Snapshot
		out.Index = idx
		return out, nil
	}
	if rootFromManifest != "" {
		resourceRoot = rootFromManifest
	}
	if resourceRootOverride != "" {
		resourceRoot = resourceRootOverride
	}

	idx, err := BuildIndexFromManifestEntries(
		resourceRoot,
		"rpc",
		true,
		out.DoctorHealthy,
		snapshot,
		manifestVersion,
		entries,
	)
	if err != nil {
		if resourceRootOverride == "" {
			return emptyRPCResult(
				out,
				snapshot,
				fmt.Sprintf("published release failed local validation: %v", err),
			), nil
		}
		return out, err
	}
	out.ResourceRoot = idx.ResourceRoot
	out.Snapshot = snapshot
	out.Index = idx
	return out, nil
}

func emptyRPCResult(out *DiscoverResult, snapshot *SnapshotSummary, warning string) *DiscoverResult {
	out.ResourceRoot = ""
	out.Snapshot = snapshot
	out.Index = &ReleaseIndex{
		Source:        "rpc",
		RPCAvailable:  true,
		DoctorHealthy: out.DoctorHealthy,
		Snapshot:      snapshot,
		byRel:         map[string]int{},
	}
	if warning != "" {
		out.Warnings = append(out.Warnings, warning)
	}
	return out
}

func parseCatalogStatus(raw json.RawMessage) (*SnapshotSummary, string, bool) {
	if len(raw) == 0 || string(raw) == "null" {
		return nil, "", false
	}
	var payload struct {
		Available               bool                     `json:"available"`
		Status                  string                   `json:"status"`
		StatusCode              string                   `json:"status_code"`
		DistributionStatus      string                   `json:"distribution_status"`
		DistributionStatusCode  string                   `json:"distribution_status_code"`
		AppVersion              string                   `json:"app_version"`
		BundleVersion           string                   `json:"bundle_version"`
		ConnectionGroupName     string                   `json:"connection_group_name"`
		AddressablesRoot        string                   `json:"addressables_root"`
		LauncherMetadata        *LauncherMetadataSummary `json:"launcher_metadata"`
		GameMainConfigBootstrap *GameMainConfigSummary   `json:"game_main_config_bootstrap"`
		Version                 *struct {
			ID                   string  `json:"id"`
			CompletedUnixSeconds *uint64 `json:"completed_unix_seconds"`
			ResourceRoot         string  `json:"resource_root"`
		} `json:"version"`
	}
	if err := json.Unmarshal(raw, &payload); err != nil || !payload.Available {
		return nil, "", false
	}
	snap := &SnapshotSummary{
		Status:                 payload.Status,
		StatusCode:             payload.StatusCode,
		DistributionStatus:     payload.DistributionStatus,
		DistributionStatusCode: payload.DistributionStatusCode,
		AppVersion:             payload.AppVersion,
		BundleVersion:          payload.BundleVersion,
		ConnectionGroupName:    payload.ConnectionGroupName,
		AddressablesRoot:       payload.AddressablesRoot,
		LauncherMetadata:       payload.LauncherMetadata,
		GameMainConfig:         payload.GameMainConfigBootstrap,
	}
	root := ""
	if payload.Version != nil {
		snap.VersionID = payload.Version.ID
		snap.CompletedUnixSeconds = payload.Version.CompletedUnixSeconds
		root = payload.Version.ResourceRoot
	}
	return snap, root, true
}

func parseCatalogAvailability(raw json.RawMessage) (bool, bool) {
	if len(raw) == 0 || string(raw) == "null" {
		return false, false
	}
	var payload struct {
		Available *bool `json:"available"`
	}
	if err := json.Unmarshal(raw, &payload); err != nil || payload.Available == nil {
		return false, false
	}
	return *payload.Available, true
}

func fetchAllManifestEntries(ctx context.Context, backend Backend) ([]manifestEntry, int, string, error) {
	const pageSize = 500
	offset := 0
	var all []manifestEntry
	var version int
	var root string
	for {
		page, err := backend.ResourceManifest(ctx, offset, pageSize)
		if err != nil {
			return nil, 0, "", err
		}
		if !page.Available {
			return nil, 0, "", fmt.Errorf("resource.manifest available=false")
		}
		if root == "" {
			root = page.ResourceRoot
		}
		if version == 0 {
			version = page.ManifestVersion
		}
		for _, e := range page.Entries {
			var bytes uint64
			if e.Bytes != nil {
				bytes = *e.Bytes
			}
			all = append(all, manifestEntry{
				URL:         e.URL,
				Destination: e.Destination,
				Bytes:       bytes,
				BLAKE3:      e.BLAKE3,
			})
		}
		offset += len(page.Entries)
		if len(page.Entries) == 0 || offset >= page.TotalEntries {
			break
		}
	}
	return all, version, root, nil
}