backend

type Backend interface {
	// Prepare runs once before any task. Pulls images, creates networks, etc.
	Prepare(ctx context.Context, run RunSpec) error

	// RunTask executes a single TaskInvocation and returns its result.
	// Implementations stream logs through inv.LogSink.
	RunTask(ctx context.Context, inv TaskInvocation) (TaskResult, error)

	// Cleanup runs once after all tasks (success or failure). Removes containers,
	// temporary networks, etc. Workspace cleanup is the engine's responsibility.
	Cleanup(ctx context.Context) error
}

type LogSink interface {
	StepLog(taskName, stepName, stream string, line string)
}

type RunSpec struct {
	RunID      string            // stable per-invocation
	Pipeline   string            // pipeline name (or task name in single-task mode)
	Images     []string          // images to pre-pull
	Workspaces map[string]string // workspace name → host path
}

type StepResult struct {
	Name     string
	Status   StepStatus
	ExitCode int
	Started  time.Time
	Ended    time.Time
}

type StepStatus string

type TaskInvocation struct {
	RunID       string
	PipelineRun string
	TaskRunName string                            // <pipelineRun>-<task>
	Task        tektontypes.TaskSpec              // resolved spec — no $(params.x) left
	Params      map[string]tektontypes.ParamValue // already-evaluated params
	Workspaces  map[string]WorkspaceMount         // task-workspace-name → host mount
	ContextVars map[string]string                 // $(context.taskRun.name) etc.
	LogSink     LogSink                           // engine-supplied sink
	ResultsHost string                            // host dir bind-mounted as /tekton/results
}

type TaskResult struct {
	Status  TaskStatus
	Started time.Time
	Ended   time.Time
	Steps   []StepResult
	Results map[string]string // result name → value (read from /tekton/results/<name>)
	Err     error             // populated when Status is TaskInfraFailed
}

type TaskStatus string

type WorkspaceMount struct {
	HostPath string
	ReadOnly bool
	SubPath  string
}