package models

import (
	"context"

	"github.com/bluesky-social/indigo/atproto/syntax"
)

// Adapter is the core of the spindle. It can use its own way to configure and
// run the workflows. The workflow definition can be either yaml files in git
// repositories or even from dedicated web UI.
//
// An adapter is expected to be hold all created workflow runs.
type Adapter interface {
	// Init intializes the adapter
	Init() error

	// Shutdown gracefully shuts down background jobs
	Shutdown(ctx context.Context) error

	// SetupRepo ensures adapter connected to the repository.
	// This usually includes adding repository watcher that does sparse-clone.
	SetupRepo(ctx context.Context, repo syntax.ATURI) error

	// ListWorkflowDefs parses and returns all workflow definitions in the given
	// repository at the specified revision
	ListWorkflowDefs(ctx context.Context, repo syntax.ATURI, rev string) ([]WorkflowDef, error)

	// EvaluateEvent consumes a trigger event and returns a list of triggered
	// workflow runs. It is expected to return immediately after scheduling the
	// workflows.
	EvaluateEvent(ctx context.Context, event Event) ([]WorkflowRun, error)

	// GetActiveWorkflowRun returns current state of specific workflow run.
	// This method will be called regularly for active workflow runs.
	GetActiveWorkflowRun(ctx context.Context, runId syntax.ATURI) (WorkflowRun, error)




	// NOTE: baisically I'm not sure about this method.
	//       How to properly sync workflow.run states?
	//
	//       for adapters with external engine, they will hold every past
	//       workflow.run objects.
	//       for adapters with internal engine, they... should also hold every
	//       past workflow.run objects..?
	//
	//       problem:
	//       when spindle suffer downtime (spindle server shutdown),
	//       external `workflow.run`s might be unsynced in "running" or "pending" state
	//       same for internal `workflow.run`s.
	//
	//       BUT, spindle itself is holding the runs,
	//       so it already knows unsynced workflows (=workflows not finished)
	//       therefore, it can just fetch them again.
	//       for adapters with internal engines, they will fail to fetch previous
	//       run.
	//       Leaving spindle to mark the run as "Lost" or "Failed".
	//       Because of _lacking_ adaters, spindle should be able to manually
	//       mark unknown runs with "lost" state.
	//
	//       GetWorkflowRun : used to get background crawling
	//         XCodeCloud: ok
	//         Nixery: (will fail if unknown) -> spindle will mark workflow as failed anyways
	//       StreamWorkflowRun : used to notify real-time updates
	//         XCodeCloud: ok (but old events will be lost)
	//         Nixery: same. old events on spindle downtime will be lost
	//
	//
	//       To avoid this, each adapters should hold outbox buffer
	//
	// |
	// v

	// StreamWorkflowRun(ctx context.Context) <-chan WorkflowRun


	// ListActiveWorkflowRuns returns current list of active workflow runs.
	// Runs where status is either Pending or Running
	ListActiveWorkflowRuns(ctx context.Context) ([]WorkflowRun, error)
	SubscribeWorkflowRun(ctx context.Context) <-chan WorkflowRun




	// StreamWorkflowRunLogs streams logs for a running workflow execution
	StreamWorkflowRunLogs(ctx context.Context, runId syntax.ATURI, handle func(line LogLine) error) error

	// CancelWorkflowRun attempts to stop a running workflow execution.
	// It won't do anything when the workflow has already completed.
	CancelWorkflowRun(ctx context.Context, runId syntax.ATURI) error
}