package app

import (
	"context"
	"errors"
	"fmt"
	"os"
	"strings"
	"time"

	"gitea.maximumdirect.net/eric/narratio/internal/adapters/audita"
	"gitea.maximumdirect.net/eric/narratio/internal/adapters/seriatim"
	"gitea.maximumdirect.net/eric/narratio/internal/adapters/whisperx"
	"gitea.maximumdirect.net/eric/narratio/internal/artifactmodel"
	"gitea.maximumdirect.net/eric/narratio/internal/artifacts"
	"gitea.maximumdirect.net/eric/narratio/internal/config"
	"gitea.maximumdirect.net/eric/narratio/internal/manifest"
	"gitea.maximumdirect.net/eric/narratio/internal/stage"
)

type RunOptions struct {
	Force              bool
	SelectedArtifacts  []string
	EffectiveArtifacts artifacts.EffectiveArtifactSet
	Env                *Env
}

type RunSummary struct {
	SessionID    string
	RunID        string
	ManifestPath string
	StageNames   []string
	Executed     []string
	Skipped      []string
}

type pipelineExecutor func(context.Context, *config.Config, BoundedPlan, RunOptions) (*RunSummary, error)

func executePlan(ctx context.Context, cfg *config.Config, plan BoundedPlan, opts RunOptions) (summary *RunSummary, resultErr error) {
	return executePlanWithDependencies(ctx, cfg, plan, opts, invocationDependencies{})
}

func executePlanWithDependencies(ctx context.Context, cfg *config.Config, plan BoundedPlan, opts RunOptions, dependencies invocationDependencies) (summary *RunSummary, resultErr error) {
	dependencies = dependencies.normalized()
	runtime, err := prepareInvocation(ctx, cfg, plan, opts, dependencies)
	if err != nil {
		return nil, err
	}
	if err := prepareInvocationLayout(runtime); err != nil {
		return nil, err
	}

	lock, err := runtime.artifactStore.AcquireSessionLockForContext(ctx, runtime.identity.Campaign, runtime.identity.SessionID)
	if err != nil {
		return nil, fmt.Errorf("acquire session lock: %w", err)
	}
	defer func() {
		if releaseErr := runtime.artifactStore.ReleaseSessionLock(lock); releaseErr != nil {
			if resultErr == nil {
				resultErr = fmt.Errorf("release session lock: %w", releaseErr)
			} else {
				resultErr = errors.Join(resultErr, fmt.Errorf("release session lock: %w", releaseErr))
			}
		}
	}()

	if err := initializeLockedInvocation(runtime); err != nil {
		return nil, err
	}
	if err := composeInvocation(runtime); err != nil {
		return nil, err
	}

	for _, selected := range runtime.stages {
		runtime.stageNames = append(runtime.stageNames, selected.Name())
		outcome, err := executeSelectedStage(runtime, selected)
		if err != nil {
			return nil, err
		}
		if outcome.executed {
			runtime.executed = append(runtime.executed, selected.Name())
		}
		if outcome.skipped {
			runtime.skipped = append(runtime.skipped, selected.Name())
		}
	}
	return finalizeInvocation(runtime)
}

func stagesContainAny(stages []stage.Stage, names ...string) bool {
	wanted := make(map[string]struct{}, len(names))
	for _, name := range names {
		wanted[name] = struct{}{}
	}
	for _, candidate := range stages {
		if candidate == nil {
			continue
		}
		if _, ok := wanted[candidate.Name()]; ok {
			return true
		}
	}
	return false
}

func persistSessionTerminalFailure(
	ctx context.Context,
	sessionStore manifest.Store,
	sessionManifestPath string,
	sessionManifest *manifest.Manifest,
	operationErr error,
	at time.Time,
) error {
	if operationErr == nil {
		return nil
	}

	if sessionManifest != nil {
		sessionManifest.RecordFailure(at, operationErr.Error())
	}

	sessionErr := sessionStore.Save(ctx, sessionManifestPath, sessionManifest)
	return errors.Join(
		operationErr,
		wrapTerminalPersistenceError("save terminal session manifest", sessionErr),
	)
}

func wrapTerminalPersistenceError(operation string, err error) error {
	if err == nil {
		return nil
	}
	return fmt.Errorf("%s: %w", operation, err)
}

func buildDefaultWhisperXClient(cfg *config.Config) (whisperx.Client, error) {
	if cfg == nil || cfg.Pipeline == nil {
		return &whisperx.NoopClient{}, nil
	}

	wx := cfg.Pipeline.WhisperX
	if strings.TrimSpace(wx.TranscribeURL) == "" {
		// Compatibility fallback for tests or internal call paths that bypass config validation.
		return &whisperx.NoopClient{}, nil
	}

	retries := 0
	if wx.Retries != nil {
		retries = *wx.Retries
	}

	client, err := whisperx.NewHTTPClientFromConfigValues(
		wx.TranscribeURL,
		wx.Language,
		wx.Timeout,
		wx.RetryDelay,
		retries,
	)
	if err != nil {
		return nil, fmt.Errorf("from pipeline.whisperx: %w", err)
	}
	return client, nil
}

func buildDefaultSeriatimRunner(cfg *config.Config) (seriatim.Runner, error) {
	if cfg == nil || cfg.Pipeline == nil {
		return &seriatim.NoopRunner{}, nil
	}

	s := cfg.Pipeline.Seriatim
	if strings.TrimSpace(s.Binary) == "" || strings.TrimSpace(s.Timeout) == "" || strings.TrimSpace(s.OutputSchema) == "" {
		// Compatibility fallback for tests or internal call paths that bypass config validation/defaults.
		return &seriatim.NoopRunner{}, nil
	}

	report := false
	if s.Report != nil {
		report = *s.Report
	}
	runner, err := seriatim.NewSubprocessRunnerFromConfigValues(
		s.Binary,
		s.Timeout,
		s.OutputSchema,
		s.CoalesceGap,
		report,
		seriatim.EnvConfig{
			OverlapWordRunGap:           s.Env.OverlapWordRunGap,
			OverlapWordRunReorderWindow: s.Env.OverlapWordRunReorderWindow,
			BackchannelMaxDuration:      s.Env.BackchannelMaxDuration,
			FillerMaxDuration:           s.Env.FillerMaxDuration,
		},
	)
	if err != nil {
		return nil, fmt.Errorf("from pipeline.seriatim: %w", err)
	}
	return runner, nil
}

func buildDefaultAuditaRunner(cfg *config.Config) (audita.Runner, error) {
	if cfg == nil || cfg.Pipeline == nil {
		return &audita.NoopRunner{}, nil
	}

	a := cfg.Pipeline.Audita
	if strings.TrimSpace(a.Binary) == "" || strings.TrimSpace(a.Timeout) == "" {
		// Compatibility fallback for tests or internal call paths that bypass config validation/defaults.
		return &audita.NoopRunner{}, nil
	}

	timeout, err := time.ParseDuration(a.Timeout)
	if err != nil {
		return nil, fmt.Errorf("parse pipeline.audita.timeout %q: %w", a.Timeout, err)
	}
	runner, err := audita.NewSubprocessRunner(audita.SubprocessRunnerConfig{
		Binary: a.Binary, Timeout: timeout, Credentials: a.Credentials,
		Modules: append(a.Modules[:0:0], a.Modules...),
		Overlay: a.Overlay, ProposalProfile: a.ProposalProfile,
		ValidationProfile:     a.ValidationProfile,
		TranscriptDescription: a.TranscriptDescription, ConfigPath: a.ConfigPath,
		OutputSchema: a.OutputSchema,
	})
	if err != nil {
		return nil, fmt.Errorf("from pipeline.audita: %w", err)
	}
	return runner, nil
}

func loadManifestAtPathIfPresent(ctx context.Context, store manifest.Store, path string) (*manifest.Manifest, bool, error) {
	exists, err := fileExists(path)
	if err != nil {
		return nil, false, fmt.Errorf("check manifest existence %q: %w", path, err)
	}
	if exists {
		m, err := store.Load(ctx, path)
		if err != nil {
			return nil, false, fmt.Errorf("load manifest %q: %w", path, err)
		}
		return m, true, nil
	}
	return nil, false, nil
}

func fileExists(path string) (bool, error) {
	_, err := os.Stat(path)
	if err == nil {
		return true, nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return false, err
}

func mapResultOutputs(stageName string, result *stage.StageResult, runID string) []manifest.ArtifactRecord {
	if result == nil || len(result.Outputs) == 0 {
		return nil
	}

	runID = strings.TrimSpace(runID)
	out := make([]manifest.ArtifactRecord, 0, len(result.Outputs))
	for _, ref := range result.Outputs {
		localPath := ref.AbsolutePath
		if localPath == "" {
			localPath = ref.RelativePath
		}
		kind := ref.Kind
		sourceID := strings.TrimSpace(ref.SourceID)
		if sourceID == "" {
			if stageName == "analyze" {
				sourceID = artifacts.ConfiguredArtifactSourceID(ref.Kind)
				kind = "scriptorium_artifact"
			} else {
				sourceID = sourceIDForOutputKind(kind)
			}
		}
		producerRunID := strings.TrimSpace(ref.ProducerRunID)
		if producerRunID == "" {
			producerRunID = runID
		}
		out = append(out, manifest.ArtifactRecord{
			Kind:               kind,
			SourceID:           sourceID,
			LocalPath:          localPath,
			ArchivePath:        ref.ArchivePath,
			Contract:           cloneContractMetadata(ref.Contract),
			ExternalProvenance: cloneExternalProvenance(ref.ExternalProvenance),
			ProducerRunID:      producerRunID,
			RemoteKey:          ref.RemoteKey,
			Checksum:           ref.Checksum,
		})
	}

	return out
}

func validateStageResult(result *stage.StageResult) error {
	if result == nil {
		return nil
	}
	switch result.Disposition {
	case stage.StageDispositionSucceeded:
		if strings.TrimSpace(result.SkipReason) != "" {
			return fmt.Errorf("successful result contains a skip reason")
		}
		return nil
	case stage.StageDispositionSkipped:
		if strings.TrimSpace(result.SkipReason) == "" {
			return fmt.Errorf("skipped result requires a skip reason")
		}
		if len(result.Outputs) != 0 {
			return fmt.Errorf("skipped result contains %d output(s)", len(result.Outputs))
		}
		return nil
	default:
		return fmt.Errorf("unsupported stage result disposition %q", result.Disposition)
	}
}

func cloneContractMetadata(value *artifactmodel.ContractMetadata) *artifactmodel.ContractMetadata {
	if value == nil {
		return nil
	}
	cloned := *value
	return &cloned
}

func cloneExternalProvenance(value *artifactmodel.ExternalProvenance) *artifactmodel.ExternalProvenance {
	if value == nil {
		return nil
	}
	cloned := *value
	return &cloned
}

func sourceIDForOutputKind(kind string) string {
	trimmed := strings.TrimSpace(kind)
	if trimmed == "" {
		return ""
	}
	if trimmed == "session_bounds" {
		return artifacts.ArtifactBoundsSession
	}
	for _, spec := range artifactmodel.RuntimeTranscriptArtifacts() {
		if spec.OutputKind == trimmed {
			return spec.SourceID
		}
	}
	return ""
}

func applyStageResultToManifest(m *manifest.Manifest, stageName string, result *stage.StageResult) {
	if m == nil || result == nil {
		return
	}
	sr := m.Stages[stageName]
	if sr == nil {
		return
	}
	if len(result.Logs) > 0 {
		sr.Logs = append([]string(nil), result.Logs...)
	}
	if len(result.GeneratedConfigs) > 0 {
		sr.GeneratedConfigs = append([]string(nil), result.GeneratedConfigs...)
	}
	if len(result.Metadata) > 0 {
		sr.Metadata = result.Metadata
	}
}

type invocationIdentity struct {
	Campaign        string
	SessionID       string
	RunID           string
	LocalWorkDir    string
	LocalSpoolDir   string
	S3Bucket        string
	S3SessionPrefix string
	S3RunPrefix     string
}

func resolveInvocationIdentity(cfg *config.Config, runID string) (invocationIdentity, error) {
	if cfg == nil || cfg.Pipeline == nil || cfg.Campaign == nil || cfg.Session == nil {
		return invocationIdentity{}, fmt.Errorf("resolved configuration requires pipeline, campaign, and session")
	}

	campaign := strings.TrimSpace(cfg.Session.Campaign)
	configuredCampaign := strings.TrimSpace(config.CampaignID(cfg.Campaign))
	if campaign == "" {
		return invocationIdentity{}, fmt.Errorf("configured session campaign is required")
	}
	if configuredCampaign == "" {
		return invocationIdentity{}, fmt.Errorf("configured campaign is required")
	}
	if campaign != configuredCampaign {
		return invocationIdentity{}, fmt.Errorf("configured session campaign %q does not match configured campaign %q", campaign, configuredCampaign)
	}

	sessionID := strings.TrimSpace(cfg.Session.SessionID)
	if sessionID == "" {
		return invocationIdentity{}, fmt.Errorf("configured session_id is required")
	}
	runID = strings.TrimSpace(runID)
	if runID == "" {
		return invocationIdentity{}, fmt.Errorf("run id is required")
	}

	identity := invocationIdentity{
		Campaign:     campaign,
		SessionID:    sessionID,
		RunID:        runID,
		LocalWorkDir: artifacts.SessionRunRootForCampaign(cfg.Pipeline.Workspace.Root, campaign, sessionID, runID),
	}
	if spoolRoot := strings.TrimSpace(cfg.Pipeline.Spool.Root); spoolRoot != "" {
		identity.LocalSpoolDir = artifacts.SessionSpoolAudioDir(spoolRoot, campaign, sessionID, runID)
	}
	if s3 := cfg.Pipeline.Storage.S3; s3 != nil {
		identity.S3Bucket = strings.TrimSpace(s3.Bucket)
		identity.S3SessionPrefix = artifacts.S3SessionPrefix(s3.RootPrefix, campaign, sessionID)
		identity.S3RunPrefix = artifacts.S3RunPrefix(identity.S3SessionPrefix, runID)
	}
	return identity, nil
}

func (identity invocationIdentity) validateSessionManifest(m *manifest.Manifest) error {
	if m == nil {
		return fmt.Errorf("persisted manifest is nil")
	}
	if sessionID := strings.TrimSpace(m.SessionID); sessionID != "" && sessionID != identity.SessionID {
		return fmt.Errorf("persisted manifest session_id %q does not match configured session_id %q", sessionID, identity.SessionID)
	}
	if campaign := strings.TrimSpace(m.Campaign); campaign != "" && campaign != identity.Campaign {
		return fmt.Errorf("persisted manifest campaign %q does not match configured campaign %q", campaign, identity.Campaign)
	}
	return nil
}

func (identity invocationIdentity) applyToSessionManifest(m *manifest.Manifest) {
	if m == nil {
		return
	}
	m.SessionID = identity.SessionID
	m.Campaign = identity.Campaign
	m.RunID = identity.RunID
	m.LocalWorkDir = identity.LocalWorkDir
	m.LocalSpoolDir = identity.LocalSpoolDir
	m.S3Bucket = identity.S3Bucket
	m.S3SessionPrefix = identity.S3SessionPrefix
	m.S3RunPrefix = identity.S3RunPrefix
}

func manifestPathFor(cfg *config.Config) string {
	return artifacts.SessionManifestPathForCampaign(
		cfg.Pipeline.Workspace.Root,
		cfg.Session.Campaign,
		cfg.Session.SessionID,
	)
}

func needsObjectStoreForRun(cfg *config.Config, stages []stage.Stage, effectiveSets ...artifacts.EffectiveArtifactSet) bool {
	if cfg == nil || cfg.Pipeline == nil || cfg.Session == nil {
		return false
	}
	effective := artifacts.EffectiveArtifactSet{}
	if len(effectiveSets) > 0 {
		effective = effectiveSets[0]
	}
	if !effective.Resolved() && cfg.Pipeline.Scriptorium != nil {
		var err error
		effective, err = artifacts.ResolveEffectiveArtifactSet(
			artifacts.ConfiguredArtifactDefinitions(cfg.Pipeline.Scriptorium.Artifacts),
			nil,
		)
		if err != nil {
			return false
		}
	}
	stageRequested := func(name string) bool {
		for _, s := range stages {
			if s != nil && s.Name() == name {
				return true
			}
		}
		return false
	}

	if cfg.Session.Inputs.AudioS3 != nil && stageRequested("prepare") {
		return true
	}
	if stageRequested("prepare") {
		requirements := artifacts.CollectPreviousArtifactRequirements(configuredScriptoriumArtifacts(cfg), effective)
		if len(requirements) > 0 && strings.TrimSpace(cfg.Session.PreviousSessionID) != "" {
			return true
		}
	}
	if !stageRequested("publish") {
		return false
	}
	if cfg.Pipeline.Publish == nil {
		return false
	}
	if cfg.Pipeline.Publish.Enabled != nil && !*cfg.Pipeline.Publish.Enabled {
		return false
	}
	if cfg.Pipeline.Publish.UploadRun != nil && !*cfg.Pipeline.Publish.UploadRun {
		return false
	}
	return true
}

func needsNotariusForRun(cfg *config.Config, stages []stage.Stage) bool {
	if cfg == nil || cfg.Pipeline == nil || cfg.Pipeline.Notarius == nil || !cfg.Pipeline.Notarius.Enabled {
		return false
	}
	for _, candidate := range stages {
		if candidate != nil && candidate.Name() == "extract" {
			return true
		}
	}
	return false
}

func configuredScriptoriumArtifacts(cfg *config.Config) map[string]config.ScriptoriumArtifactConfig {
	if cfg == nil || cfg.Pipeline == nil || cfg.Pipeline.Scriptorium == nil {
		return nil
	}
	return cfg.Pipeline.Scriptorium.Artifacts
}