package spindle

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/bluesky-social/indigo/atproto/syntax"
	"tangled.org/core/api/tangled"
	"tangled.org/core/eventconsumer"
	"tangled.org/core/spindle/db"
	"tangled.org/core/spindle/git"
	"tangled.org/core/spindle/models"
	"tangled.org/core/tap"
	"tangled.org/core/tid"
	"tangled.org/core/workflow"
)

func (s *Spindle) processEvent(ctx context.Context, evt tap.Event) error {
	l := s.l.With("component", "tapIndexer")

	var err error
	switch evt.Type {
	case tap.EvtRecord:
		switch evt.Record.Collection.String() {
		case tangled.SpindleMemberNSID:
			err = s.processMember(ctx, evt)
		case tangled.RepoNSID:
			err = s.processRepo(ctx, evt)
		case tangled.RepoCollaboratorNSID:
			err = s.processCollaborator(ctx, evt)
		case tangled.RepoPullNSID:
			err = s.processPull(ctx, evt)
		}
	case tap.EvtIdentity:
		// no-op
	}

	if err != nil {
		l.Error("failed to process message. will retry later", "event.ID", evt.ID, "err", err)
		return err
	}
	return nil
}

// NOTE: make sure to return nil if we don't need to retry (e.g. forbidden, unrelated)

func (s *Spindle) processMember(ctx context.Context, evt tap.Event) error {
	l := s.l.With("component", "tapIndexer", "record", evt.Record.AtUri())

	l.Info("processing spindle.member record")

	// only listen to members
	if ok, err := s.e.IsSpindleMemberInviteAllowed(evt.Record.Did, s.cfg.Server.Did()); !ok || err != nil {
		l.Warn("forbidden request: member invite not allowed", "did", evt.Record.Did, "error", err)
		return nil
	}

	switch evt.Record.Action {
	case tap.RecordCreateAction, tap.RecordUpdateAction:
		record := tangled.SpindleMember{}
		if err := json.Unmarshal(evt.Record.Record, &record); err != nil {
			return fmt.Errorf("parsing record: %w", err)
		}

		domain := s.cfg.Server.Hostname
		if record.Instance != domain {
			l.Info("domain mismatch", "domain", record.Instance, "expected", domain)
			return nil
		}

		created, err := time.Parse(record.CreatedAt, time.RFC3339)
		if err != nil {
			created = time.Now()
		}
		if err := db.AddSpindleMember(s.db, db.SpindleMember{
			Did:      evt.Record.Did,
			Rkey:     evt.Record.Rkey.String(),
			Instance: record.Instance,
			Subject:  syntax.DID(record.Subject),
			Created:  created,
		}); err != nil {
			l.Error("failed to add member", "error", err)
			return fmt.Errorf("adding member to db: %w", err)
		}
		if err := s.e.AddSpindleMember(syntax.DID(record.Subject), s.cfg.Server.Did()); err != nil {
			return fmt.Errorf("adding member to rbac: %w", err)
		}
		if err := s.tap.AddRepos(ctx, []syntax.DID{syntax.DID(record.Subject)}); err != nil {
			return fmt.Errorf("adding did to tap", err)
		}

		l.Info("added member", "member", record.Subject)
		return nil

	case tap.RecordDeleteAction:
		var (
			did  = evt.Record.Did.String()
			rkey = evt.Record.Rkey.String()
		)
		member, err := db.GetSpindleMember(s.db, did, rkey)
		if err != nil {
			return fmt.Errorf("finding member: %w", err)
		}

		if err := db.RemoveSpindleMember(s.db, did, rkey); err != nil {
			return fmt.Errorf("removing member from db: %w", err)
		}
		if err := s.e.RemoveSpindleMember(member.Subject, s.cfg.Server.Did()); err != nil {
			return fmt.Errorf("removing member from rbac: %w", err)
		}
		if err := s.tapSafeRemoveDid(ctx, member.Subject); err != nil {
			return fmt.Errorf("removing did from tap: %w", err)
		}

		l.Info("removed member", "member", member.Subject)
		return nil
	}
	return nil
}

func (s *Spindle) processCollaborator(ctx context.Context, evt tap.Event) error {
	l := s.l.With("component", "tapIndexer", "record", evt.Record.AtUri())

	l.Info("processing repo.collaborator record")

	// only listen to members
	if ok, err := s.e.IsSpindleMember(evt.Record.Did, s.cfg.Server.Did()); !ok || err != nil {
		l.Warn("forbidden request: not spindle member", "did", evt.Record.Did, "err", err)
		return nil
	}

	switch evt.Record.Action {
	case tap.RecordCreateAction, tap.RecordUpdateAction:
		record := tangled.RepoCollaborator{}
		if err := json.Unmarshal(evt.Record.Record, &record); err != nil {
			l.Error("invalid record", "err", err)
			return fmt.Errorf("parsing record: %w", err)
		}

		// retry later if target repo is not ingested yet
		if _, err := s.db.GetRepo(syntax.ATURI(record.Repo)); err != nil {
			l.Warn("target repo is not ingested yet", "repo", record.Repo, "err", err)
			return fmt.Errorf("target repo is unknown")
		}

		// check perms for this user
		if ok, err := s.e.IsRepoCollaboratorInviteAllowed(evt.Record.Did, syntax.ATURI(record.Repo)); !ok || err != nil {
			l.Warn("forbidden request collaborator invite not allowed", "did", evt.Record.Did, "err", err)
			return nil
		}

		if err := s.db.PutRepoCollaborator(&db.RepoCollaborator{
			Did:     evt.Record.Did,
			Rkey:    evt.Record.Rkey,
			Repo:    syntax.ATURI(record.Repo),
			Subject: syntax.DID(record.Subject),
		}); err != nil {
			return fmt.Errorf("adding collaborator to db: %w", err)
		}
		if err := s.e.AddRepoCollaborator(syntax.DID(record.Subject), syntax.ATURI(record.Repo)); err != nil {
			return fmt.Errorf("adding collaborator to rbac: %w", err)
		}
		if err := s.tap.AddRepos(ctx, []syntax.DID{syntax.DID(record.Subject)}); err != nil {
			return fmt.Errorf("adding did to tap: %w", err)
		}

		l.Info("add repo collaborator", "subejct", record.Subject, "repo", record.Repo)
		return nil

	case tap.RecordDeleteAction:
		// get existing collaborator
		collaborator, err := s.db.GetRepoCollaborator(evt.Record.Did, evt.Record.Rkey)
		if err != nil {
			return fmt.Errorf("failed to get existing collaborator info: %w", err)
		}

		// check perms for this user
		if ok, err := s.e.IsRepoCollaboratorInviteAllowed(evt.Record.Did, collaborator.Repo); !ok || err != nil {
			l.Warn("forbidden request collaborator invite not allowed", "did", evt.Record.Did, "err", err)
			return nil
		}

		if err := s.db.RemoveRepoCollaborator(collaborator.Subject, collaborator.Rkey); err != nil {
			return fmt.Errorf("removing collaborator from db: %w", err)
		}
		if err := s.e.RemoveRepoCollaborator(collaborator.Subject, collaborator.Repo); err != nil {
			return fmt.Errorf("removing collaborator from rbac: %w", err)
		}
		if err := s.tapSafeRemoveDid(ctx, collaborator.Subject); err != nil {
			return fmt.Errorf("removing did from tap: %w", err)
		}

		l.Info("removed repo collaborator", "subejct", collaborator.Subject, "repo", collaborator.Repo)
		return nil
	}
	return nil
}

func (s *Spindle) processRepo(ctx context.Context, evt tap.Event) error {
	l := s.l.With("component", "tapIndexer", "record", evt.Record.AtUri())

	l.Info("processing repo record")

	// only listen to members
	if ok, err := s.e.IsSpindleMember(evt.Record.Did, s.cfg.Server.Did()); !ok || err != nil {
		l.Warn("forbidden request: not spindle member", "did", evt.Record.Did, "err", err)
		return nil
	}

	switch evt.Record.Action {
	case tap.RecordCreateAction, tap.RecordUpdateAction:
		record := tangled.Repo{}
		if err := json.Unmarshal(evt.Record.Record, &record); err != nil {
			return fmt.Errorf("parsing record: %w", err)
		}

		domain := s.cfg.Server.Hostname
		if record.Spindle == nil || *record.Spindle != domain {
			if record.Spindle == nil {
				l.Info("spindle isn't configured", "name", record.Name)
			} else {
				l.Info("different spindle configured", "name", record.Name, "spindle", *record.Spindle, "domain", domain)
			}
			if err := s.db.DeleteRepo(evt.Record.Did, evt.Record.Rkey); err != nil {
				return fmt.Errorf("deleting repo from db: %w", err)
			}
			return nil
		}

		repo := &db.Repo{
			Did:  evt.Record.Did,
			Rkey: evt.Record.Rkey,
			Name: record.Name,
			Knot: record.Knot,
		}

		if err := s.db.PutRepo(repo); err != nil {
			return fmt.Errorf("adding repo to db: %w", err)
		}

		if err := s.e.AddRepo(evt.Record.AtUri()); err != nil {
			return fmt.Errorf("adding repo to rbac")
		}

		// add this knot to the event consumer
		src := eventconsumer.NewKnotSource(record.Knot)
		s.ks.AddSource(context.Background(), src)

		// setup sparse sync
		repoCloneUri := s.newRepoCloneUrl(repo.Knot, repo.Did.String(), repo.Name)
		repoPath := s.newRepoPath(repo.Did, repo.Rkey)
		if err := git.SparseSyncGitRepo(ctx, repoCloneUri, repoPath, ""); err != nil {
			return fmt.Errorf("setting up sparse-clone git repo: %w", err)
		}

		l.Info("added repo", "repo", evt.Record.AtUri())
		return nil

	case tap.RecordDeleteAction:
		// check perms for this user
		if ok, err := s.e.IsRepoOwner(evt.Record.Did, evt.Record.AtUri()); !ok || err != nil {
			l.Warn("forbidden request: not repo owner", "did", evt.Record.Did, "err", err)
			return nil
		}

		if err := s.db.DeleteRepo(evt.Record.Did, evt.Record.Rkey); err != nil {
			return fmt.Errorf("deleting repo from db: %w", err)
		}

		if err := s.e.DeleteRepo(evt.Record.AtUri()); err != nil {
			return fmt.Errorf("deleting repo from rbac: %w", err)
		}

		l.Info("deleted repo", "repo", evt.Record.AtUri())
		return nil
	}
	return nil
}

func (s *Spindle) processPull(ctx context.Context, evt tap.Event) error {
	l := s.l.With("component", "tapIndexer", "record", evt.Record.AtUri())

	l.Info("processing pull record")

	// only listen to live events
	if !evt.Record.Live {
		l.Info("skipping backfill event", "event", evt.Record.AtUri())
		return nil
	}

	switch evt.Record.Action {
	case tap.RecordCreateAction, tap.RecordUpdateAction:
		record := tangled.RepoPull{}
		if err := json.Unmarshal(evt.Record.Record, &record); err != nil {
			l.Error("invalid record", "err", err)
			return fmt.Errorf("parsing record: %w", err)
		}

		// ignore legacy records
		if record.Target == nil {
			l.Info("ignoring pull record: target repo is nil")
			return nil
		}

		// ignore patch-based and fork-based PRs
		if record.Source == nil || record.Source.Repo != nil {
			l.Info("ignoring pull record: not a branch-based pull request")
			return nil
		}

		// skip if target repo is unknown
		repo, err := s.db.GetRepo(syntax.ATURI(record.Target.Repo))
		if err != nil {
			l.Warn("target repo is not ingested yet", "repo", record.Target.Repo, "err", err)
			return fmt.Errorf("target repo is unknown")
		}

		compiler := workflow.Compiler{
			Trigger: tangled.Pipeline_TriggerMetadata{
				Kind: string(workflow.TriggerKindPullRequest),
				PullRequest: &tangled.Pipeline_PullRequestTriggerData{
					Action:       "create",
					SourceBranch: record.Source.Branch,
					SourceSha:    record.Source.Sha,
					TargetBranch: record.Target.Branch,
				},
				Repo: &tangled.Pipeline_TriggerRepo{
					Did:  repo.Did.String(),
					Knot: repo.Knot,
					Repo: repo.Name,
				},
			},
		}

		repoUri := s.newRepoCloneUrl(repo.Knot, repo.Did.String(), repo.Name)
		repoPath := s.newRepoPath(repo.Did, repo.Rkey)

		// load workflow definitions from rev (without spindle context)
		rawPipeline, err := s.loadPipeline(ctx, repoUri, repoPath, record.Source.Sha)
		if err != nil {
			// don't retry
			l.Error("failed loading pipeline", "err", err)
			return nil
		}
		if len(rawPipeline) == 0 {
			l.Info("no workflow definition find for the repo. skipping the event")
			return nil
		}
		tpl := compiler.Compile(compiler.Parse(rawPipeline))
		// TODO: pass compile error to workflow log
		for _, w := range compiler.Diagnostics.Errors {
			l.Error(w.String())
		}
		for _, w := range compiler.Diagnostics.Warnings {
			l.Warn(w.String())
		}

		pipelineId := models.PipelineId{
			Knot: tpl.TriggerMetadata.Repo.Knot,
			Rkey: tid.TID(),
		}
		if err := s.db.CreatePipelineEvent(pipelineId.Rkey, tpl, s.n); err != nil {
			l.Error("failed to create pipeline event", "err", err)
			return nil
		}
		err = s.processPipeline(ctx, tpl, pipelineId)
		if err != nil {
			// don't retry
			l.Error("failed processing pipeline", "err", err)
			return nil
		}
	case tap.RecordDeleteAction:
		// no-op
	}
	return nil
}

func (s *Spindle) tapSafeRemoveDid(ctx context.Context, did syntax.DID) error {
	known, err := s.db.IsKnownDid(syntax.DID(did))
	if err != nil {
		return fmt.Errorf("ensuring did known state: %w", err)
	}
	if !known {
		if err := s.tap.RemoveRepos(ctx, []syntax.DID{did}); err != nil {
			return fmt.Errorf("removing did from tap: %w", err)
		}
	}
	return nil
}