kandev/apps/backend/internal/task/service/service.go

package service

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strings"

	"github.com/kandev/kandev/internal/common/logger"
	"github.com/kandev/kandev/internal/events/bus"
	"github.com/kandev/kandev/internal/task/repository"
	wfmodels "github.com/kandev/kandev/internal/workflow/models"
	"github.com/kandev/kandev/internal/worktree"
)

// WorktreeCleanup provides worktree cleanup on task deletion.
type WorktreeCleanup interface {
	// OnTaskDeleted is called when a task is deleted to clean up its worktree.
	OnTaskDeleted(ctx context.Context, taskID string) error
}

// WorktreeProvider extends WorktreeCleanup with query capabilities.
// Implementations that support this can be type-asserted from WorktreeCleanup.
type WorktreeProvider interface {
	WorktreeCleanup
	// GetAllByTaskID returns all worktrees associated with a task.
	GetAllByTaskID(ctx context.Context, taskID string) ([]*worktree.Worktree, error)
}

// WorktreeBatchCleaner extends WorktreeProvider with batch cleanup.
type WorktreeBatchCleaner interface {
	WorktreeProvider
	// CleanupWorktrees removes multiple worktrees in a single operation.
	CleanupWorktrees(ctx context.Context, worktrees []*worktree.Worktree) error
}

// TaskExecutionStopper stops active task execution (agent session + instance).
type TaskExecutionStopper interface {
	StopTask(ctx context.Context, taskID, reason string, force bool) error
	StopSession(ctx context.Context, sessionID, reason string, force bool) error
	StopExecution(ctx context.Context, executionID, reason string, force bool) error
}

// ProviderDefaultBranchProber resolves a provider repo's default branch
// (e.g. "main" / "master") without requiring a local clone. Used by
// AddBranchToTask to satisfy the worktree-create precondition synchronously,
// since add_branch does not trigger the executor-side backfillRepoDefaultBranch
// path. Default implementation (cmd/kandev) shells out to
// `git ls-remote --symref`; tests inject a stub via SetProviderDefaultBranchProber.
//
// Implementations MUST honour ctx cancellation so a slow / hung remote does not
// stall the calling MCP tool. Returns ("", error) on probe failure — callers
// fall through to the explicit "cannot resolve base_branch" rejection rather
// than persisting an empty-default row.
type ProviderDefaultBranchProber interface {
	ProbeDefaultBranch(ctx context.Context, provider, owner, name string) (string, error)
}

// BranchMaterializer creates a worktree on disk and persists a
// task_session_worktrees row for a newly added task_repository row, without
// restarting the agent. Used by AddBranchToTask so MCP-driven "add a branch
// to this task" actually surfaces the new worktree in the UI on the next
// poll, rather than waiting for a session relaunch.
//
// The implementation lives in cmd/kandev (it needs worktree.Manager, the
// session/env repos, and the repository entity layer) — the service layer
// only knows the abstract capability.
// AgentBaseBranchPusher pushes an updated per-repo base-branch map to the
// agentctl instance(s) of any running execution for a task. Used by
// UpdateRepositoryBaseBranch so the changes-panel "Compare against" picker
// updates BaseCommit / Ahead / Behind live, not just at next session start.
// Implementations must be no-op-safe when the task has no running execution.
type AgentBaseBranchPusher interface {
	PushBaseBranchesForTask(ctx context.Context, taskID string, branches map[string]string)
}

type BranchMaterializer interface {
	// MaterializeBranch creates the worktree for a freshly inserted
	// task_repositories row. Best-effort: when no active session exists yet
	// the implementation may choose to no-op and let the next session launch
	// create the worktree via the standard multi-repo prepare path.
	MaterializeBranch(ctx context.Context, taskID, taskRepositoryID string) error
}

// GitArchiveCapture captures git state (commits, cumulative diff) when a task is archived.
// This allows preserving the final git state of a session for historical purposes.
type GitArchiveCapture interface {
	// CaptureArchiveSnapshot captures the git state for a session before archiving.
	// Returns nil if capture is not possible (e.g., agent not running).
	CaptureArchiveSnapshot(ctx context.Context, sessionID string) error
}

// WorkflowStepCreator creates workflow steps from a template for a workflow.
type WorkflowStepCreator interface {
	CreateStepsFromTemplate(ctx context.Context, workflowID, templateID string) error
}

// WorkflowStepGetter retrieves workflow step information.
type WorkflowStepGetter interface {
	GetStep(ctx context.Context, stepID string) (*wfmodels.WorkflowStep, error)
	// GetNextStepByPosition returns the next step after the given position for a workflow.
	// Returns nil if there is no next step (i.e., current step is the last one).
	GetNextStepByPosition(ctx context.Context, workflowID string, currentPosition int) (*wfmodels.WorkflowStep, error)
}

// PRTaskResolver resolves which tasks are associated with a GitHub PR number.
// Implemented by the github service; injected so the task service can surface a
// task by its PR number in search without coupling to the github schema.
type PRTaskResolver interface {
	FindTaskIDsByPRNumber(ctx context.Context, workspaceID string, prNumber int) ([]string, error)
}

// StartStepResolver resolves the starting step for a workflow.
type StartStepResolver interface {
	ResolveStartStep(ctx context.Context, workflowID string) (string, error)
	ResolveFirstStep(ctx context.Context, workflowID string) (string, error)
}

var (
	ErrActiveTaskSessions        = errors.New("active agent sessions exist")
	ErrInvalidRepositorySettings = errors.New("invalid repository settings")
	ErrInvalidExecutorConfig     = errors.New("invalid executor config")
)

func validateExecutorConfig(config map[string]string) error {
	if config == nil {
		return nil
	}
	policy := strings.TrimSpace(config["mcp_policy"])
	if policy == "" {
		return nil
	}
	var decoded any
	if err := json.Unmarshal([]byte(policy), &decoded); err != nil {
		return fmt.Errorf("%w: mcp_policy must be valid JSON", ErrInvalidExecutorConfig)
	}
	if _, ok := decoded.(map[string]any); !ok {
		return fmt.Errorf("%w: mcp_policy must be a JSON object", ErrInvalidExecutorConfig)
	}
	return nil
}

// Repos holds the repository sub-interfaces used by the task service.
type Repos struct {
	Workspaces       repository.WorkspaceRepository
	Tasks            repository.TaskRepository
	TaskRepos        repository.TaskRepoRepository
	Workflows        repository.WorkflowRepository
	Messages         repository.MessageRepository
	Turns            repository.TurnRepository
	Sessions         repository.SessionRepository
	GitSnapshots     repository.GitSnapshotRepository
	RepoEntities     repository.RepositoryEntityRepository
	Executors        repository.ExecutorRepository
	Environments     repository.EnvironmentRepository
	TaskEnvironments repository.TaskEnvironmentRepository
	Reviews          repository.ReviewRepository
}

// Service provides task business logic
type Service struct {
	workspaces            repository.WorkspaceRepository
	tasks                 repository.TaskRepository
	taskRepos             repository.TaskRepoRepository
	workflows             repository.WorkflowRepository
	messages              repository.MessageRepository
	turns                 repository.TurnRepository
	sessions              repository.SessionRepository
	gitSnapshots          repository.GitSnapshotRepository
	repoEntities          repository.RepositoryEntityRepository
	executors             repository.ExecutorRepository
	environments          repository.EnvironmentRepository
	taskEnvironments      repository.TaskEnvironmentRepository
	reviews               repository.ReviewRepository
	eventBus              bus.EventBus
	logger                *logger.Logger
	discoveryConfig       RepositoryDiscoveryConfig
	worktreeCleanup       WorktreeCleanup
	executionStopper      TaskExecutionStopper
	branchMaterializer    BranchMaterializer
	providerProber        ProviderDefaultBranchProber
	gitArchiveCapture     GitArchiveCapture
	workflowStepCreator   WorkflowStepCreator
	workflowStepGetter    WorkflowStepGetter
	startStepResolver     StartStepResolver
	prTaskResolver        PRTaskResolver
	quickChatDir          string // Directory for quick-chat workspaces (e.g., ~/.kandev/quick-chat)
	branchFetcher         *branchFetcher
	envDestroyer          EnvironmentDestroyer
	sessionRunningChecker SessionRunningChecker
	remoteBranchLister    RemoteBranchLister
	repoCloneLocation     RepoCloneLocation
	blockers              BlockerRepository
	comments              CommentRepository
	baseBranchPusher      AgentBaseBranchPusher
}

// NewService creates a new task service
func NewService(repos Repos, eventBus bus.EventBus, log *logger.Logger, discoveryConfig RepositoryDiscoveryConfig) *Service {
	return &Service{
		workspaces:       repos.Workspaces,
		tasks:            repos.Tasks,
		taskRepos:        repos.TaskRepos,
		workflows:        repos.Workflows,
		messages:         repos.Messages,
		turns:            repos.Turns,
		sessions:         repos.Sessions,
		gitSnapshots:     repos.GitSnapshots,
		repoEntities:     repos.RepoEntities,
		executors:        repos.Executors,
		environments:     repos.Environments,
		taskEnvironments: repos.TaskEnvironments,
		reviews:          repos.Reviews,
		eventBus:         eventBus,
		logger:           log,
		discoveryConfig:  discoveryConfig,
		branchFetcher:    newBranchFetcher(log.Zap()),
	}
}

// SetWorktreeCleanup sets the worktree cleanup handler for task deletion.
func (s *Service) SetWorktreeCleanup(cleanup WorktreeCleanup) {
	s.worktreeCleanup = cleanup
}

// SetBranchMaterializer wires the mid-session worktree materializer for
// AddBranchToTask. Optional — when unset, MCP add_branch only inserts the
// task_repositories row and the worktree appears on next session launch.
func (s *Service) SetBranchMaterializer(m BranchMaterializer) {
	s.branchMaterializer = m
}

// SetAgentBaseBranchPusher wires the live-update push for
// UpdateRepositoryBaseBranch. Optional — when unset, the persisted DB value
// is the source of truth and the new base branch takes effect at next
// session launch.
func (s *Service) SetAgentBaseBranchPusher(p AgentBaseBranchPusher) {
	s.baseBranchPusher = p
}

// SetProviderDefaultBranchProber wires the synchronous default-branch probe
// used by AddBranchToTask's GitHub-URL resolution. Optional — when unset,
// add_branch with a provider URL and no base_branch falls through to the
// "cannot resolve base_branch" rejection instead of persisting an empty row.
func (s *Service) SetProviderDefaultBranchProber(p ProviderDefaultBranchProber) {
	s.providerProber = p
}

// SetExecutionStopper wires the task execution stopper (orchestrator).
func (s *Service) SetExecutionStopper(stopper TaskExecutionStopper) {
	s.executionStopper = stopper
}

// SetGitArchiveCapture wires the git archive capture handler.
func (s *Service) SetGitArchiveCapture(capture GitArchiveCapture) {
	s.gitArchiveCapture = capture
}

// SetWorkflowStepCreator wires the workflow step creator for workflow creation.
func (s *Service) SetWorkflowStepCreator(creator WorkflowStepCreator) {
	s.workflowStepCreator = creator
}

// SetWorkflowStepGetter wires the workflow step getter for MoveTask.
func (s *Service) SetWorkflowStepGetter(getter WorkflowStepGetter) {
	s.workflowStepGetter = getter
}

// SetStartStepResolver wires the start step resolver for CreateTask.
func (s *Service) SetStartStepResolver(resolver StartStepResolver) {
	s.startStepResolver = resolver
}

// SetPRTaskResolver wires the GitHub PR→task resolver for PR-number search.
// Optional — when unset, search by PR number is a no-op.
func (s *Service) SetPRTaskResolver(resolver PRTaskResolver) {
	s.prTaskResolver = resolver
}

// SetQuickChatDir sets the directory for quick-chat workspaces.
// When set, task cleanup deletes the session directory under this path for all tasks.
func (s *Service) SetQuickChatDir(dir string) {
	s.quickChatDir = dir
}

// RemoteBranchLister fetches branches from a provider's remote (e.g. GitHub
// API) without needing a local clone. Used by ListBranches so a repo that is
// registered as remote ("Remote" badge in the UI) can serve branches before
// or even without the orchestrator finishing its clone.
type RemoteBranchLister interface {
	ListRepoBranches(ctx context.Context, owner, repo string) ([]Branch, error)
}

// SetRemoteBranchLister wires the remote branch source. Currently only GitHub
// is plumbed; other providers can be added by extending the adapter.
func (s *Service) SetRemoteBranchLister(lister RemoteBranchLister) {
	s.remoteBranchLister = lister
}

// RepoCloneLocation reports the base path the orchestrator clones repos into
// (e.g. ~/.kandev/repos or KANDEV_REPOCLONE_BASEPATH). Listing local branches
// for a cloned repo requires that path to be allow-listed by
// discoveryRoots(); without this hook clones to a custom basepath silently
// fall outside the allow-list and branch listing returns no results.
type RepoCloneLocation interface {
	ExpandedBasePath() (string, error)
}

// SetRepoCloneLocation wires the cloner so its base path is treated as an
// implicit discovery root.
func (s *Service) SetRepoCloneLocation(loc RepoCloneLocation) {
	s.repoCloneLocation = loc
}