package projectinstance

import (
	"context"
	"errors"

	"github.com/jackc/pgx/v5"
)

func (s *pgStore) GetProjectMeta(ctx context.Context, projectID int64) (string, string, int, int, error) {
	var lifecycle, activeKey string
	var selVer, planRev int
	err := s.pool.QueryRow(ctx, `
		SELECT COALESCE(lifecycle_status, 'planning'), COALESCE(active_workflow_key, ''),
		       COALESCE(workflow_selection_version, 1), COALESCE(workflow_plan_revision, 0)
		FROM projects WHERE id = $1
	`, projectID).Scan(&lifecycle, &activeKey, &selVer, &planRev)
	if errors.Is(err, pgx.ErrNoRows) {
		return "", "", 0, 0, ErrProjectNotFound
	}
	return lifecycle, activeKey, selVer, planRev, err
}

func (s *pgStore) UpdateProjectAfterActivate(ctx context.Context, projectID int64, workflowKey string, expectedVersion int, activatedBy int64) error {
	tag, err := s.pool.Exec(ctx, `
		UPDATE projects SET lifecycle_status = 'active', active_workflow_key = $2,
		       workflow_selection_version = workflow_selection_version + 1,
		       active_workflow_changed_at = now(), active_workflow_changed_by = $4,
		       updated_at = now()
		WHERE id = $1 AND workflow_selection_version = $3
	`, projectID, workflowKey, expectedVersion, activatedBy)
	if err != nil {
		return err
	}
	if tag.RowsAffected() == 0 {
		return ErrConcurrentConflict
	}
	return nil
}

func (s *pgStore) BumpPlanRevision(ctx context.Context, projectID int64, expectedPlanRevision int) (int, error) {
	var newRev int
	err := s.pool.QueryRow(ctx, `
		UPDATE projects SET workflow_plan_revision = workflow_plan_revision + 1, updated_at = now()
		WHERE id = $1 AND workflow_plan_revision = $2
		RETURNING workflow_plan_revision
	`, projectID, expectedPlanRevision).Scan(&newRev)
	if errors.Is(err, pgx.ErrNoRows) {
		return 0, ErrPlanRevisionConflict
	}
	return newRev, err
}

func (s *pgStore) GetPlanningInstance(ctx context.Context, projectID int64) (*WorkflowInstance, error) {
	row := s.pool.QueryRow(ctx, `
		SELECT id, project_id, workflow_version_id, instance_no, status, config_revision, plan_hash,
		       config_snapshot, activated_by, activated_at, created_by, created_at, updated_at
		FROM project_workflow_instances WHERE project_id = $1 AND status = 'planning'
		ORDER BY id DESC LIMIT 1
	`, projectID)
	inst, err := scanInstance(row)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, nil
	}
	return inst, err
}

func (s *pgStore) GetLiveInstance(ctx context.Context, projectID int64) (*WorkflowInstance, error) {
	row := s.pool.QueryRow(ctx, `
		SELECT id, project_id, workflow_version_id, instance_no, status, config_revision, plan_hash,
		       config_snapshot, activated_by, activated_at, created_by, created_at, updated_at
		FROM project_workflow_instances
		WHERE project_id = $1 AND status IN ('active', 'awaiting_stage_confirmation', 'termination_requested')
		ORDER BY id DESC LIMIT 1
	`, projectID)
	inst, err := scanInstance(row)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, nil
	}
	return inst, err
}

func (s *pgStore) GetGoverningInstanceForAccess(ctx context.Context, projectID int64) (*WorkflowInstance, error) {
	live, err := s.GetLiveInstance(ctx, projectID)
	if err != nil {
		return nil, err
	}
	if live != nil {
		return live, nil
	}
	row := s.pool.QueryRow(ctx, `
		SELECT id, project_id, workflow_version_id, instance_no, status, config_revision, plan_hash,
		       config_snapshot, activated_by, activated_at, created_by, created_at, updated_at
		FROM project_workflow_instances
		WHERE project_id = $1 AND status IN ('completed', 'terminated')
		ORDER BY id DESC LIMIT 1
	`, projectID)
	inst, err := scanInstance(row)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, nil
	}
	return inst, err
}

func (s *pgStore) HasLiveInstance(ctx context.Context, projectID int64) (bool, error) {
	var ok bool
	err := s.pool.QueryRow(ctx, `
		SELECT EXISTS (
			SELECT 1 FROM project_workflow_instances
			WHERE project_id = $1 AND status IN ('active', 'awaiting_stage_confirmation', 'termination_requested')
		)
	`, projectID).Scan(&ok)
	return ok, err
}