// Copyright 2025 The Forgejo Authors. All rights reserved.
// SPDX-License-Identifier: GPL-3.0-or-later

package actions

import (
	"context"
	"slices"
	"strings"

	actions_model "forgejo.org/models/actions"
	"forgejo.org/models/db"
	"forgejo.org/modules/timeutil"
)

func killRun(ctx context.Context, run *actions_model.ActionRun, newStatus actions_model.Status) error {
	return db.WithTx(ctx, func(ctx context.Context) error {
		jobs, err := actions_model.GetRunJobsByRunID(ctx, run.ID)
		if err != nil {
			return err
		}
		for _, job := range jobs {
			oldStatus := job.Status
			if oldStatus.IsDone() {
				continue
			}
			if job.TaskID == 0 {
				job.Status = newStatus
				job.Stopped = timeutil.TimeStampNow()
				_, err := actions_model.UpdateRunJobWithoutNotification(ctx, job, nil, "status", "stopped")
				if err != nil {
					return err
				}
				continue
			}
			if err := StopTask(ctx, job.TaskID, newStatus); err != nil {
				return err
			}
		}

		if run.NeedApproval {
			if err := actions_model.UpdateRunApprovalByID(ctx, run.ID, actions_model.DoesNotNeedApproval, 0); err != nil {
				return err
			}
		}

		CreateCommitStatus(ctx, jobs...)

		return nil
	})
}

func CancelRun(ctx context.Context, run *actions_model.ActionRun) error {
	return killRun(ctx, run, actions_model.StatusCancelled)
}

func ApproveRun(ctx context.Context, run *actions_model.ActionRun, doerID int64) error {
	return db.WithTx(ctx, func(ctx context.Context) error {
		jobs, err := actions_model.GetRunJobsByRunID(ctx, run.ID)
		if err != nil {
			return err
		}
		for _, job := range jobs {
			if len(job.Needs) == 0 && job.Status.IsBlocked() {
				job.Status = actions_model.StatusWaiting
				_, err := UpdateRunJob(ctx, job, nil, "status")
				if err != nil {
					return err
				}
			}
		}
		CreateCommitStatus(ctx, jobs...)

		return actions_model.UpdateRunApprovalByID(ctx, run.ID, actions_model.DoesNotNeedApproval, doerID)
	})
}

func FailRunPreExecutionError(ctx context.Context, run *actions_model.ActionRun, errorCode actions_model.PreExecutionError, details []any) error {
	if run.PreExecutionErrorCode != 0 {
		// Already have one error; keep it.
		return nil
	}

	return db.WithTx(ctx, func(ctx context.Context) error {
		run.Status = actions_model.StatusFailure
		run.PreExecutionErrorCode = errorCode
		run.PreExecutionErrorDetails = details
		if err := actions_model.UpdateRunWithoutNotification(ctx, run,
			"pre_execution_error_code", "pre_execution_error_details", "status"); err != nil {
			return err
		}

		// Also mark every pending job as Failed so nothing remains in a waiting/blocked state.
		return killRun(ctx, run, actions_model.StatusFailure)
	})
}

// Perform pre-execution checks that would affect the ability for a job to reach an executing stage.
func consistencyCheckRun(ctx context.Context, run *actions_model.ActionRun) error {
	jobs, err := actions_model.GetRunJobsByRunID(ctx, run.ID)
	if err != nil {
		return err
	}
	for _, job := range jobs {
		if stop, err := checkJobWillRevisit(ctx, job); err != nil {
			return err
		} else if stop {
			break
		}
		if stop, err := checkJobRunsOnStaticMatrixError(ctx, job); err != nil {
			return err
		} else if stop {
			break
		}
	}
	return nil
}

func checkJobWillRevisit(ctx context.Context, job *actions_model.ActionRunJob) (bool, error) {
	// If a job has a matrix like `${{ needs.other-job.outputs.some-output }}`, it will be marked as an
	// `IncompleteMatrix` job until the `other-job` is completed, and it will be marked as StatusBlocked; then when
	// `other-job` is completed, the job_emitter will check dependent jobs and revisit them.  But, it's possible that
	// the job didn't list `other-job` in its `needs: [...]` list -- in this case, a job will be marked as StatusBlocked
	// forever.
	//
	// Check to ensure that a job marked with `IncompleteMatrix` doesn't refer to a job that it doesn't have listed in
	// `needs`.  If that state is discovered, fail the job and mark a PreExecutionError on the run.

	isIncompleteMatrix, matrixNeeds, err := job.IsIncompleteMatrix()
	if err != nil {
		return false, err
	}

	if !isIncompleteMatrix || matrixNeeds == nil {
		// Not actually IncompleteMatrix, or has no information about the `${{ needs... }}` reference, nothing we can do
		// here.
		return false, nil
	}

	requiredJob := matrixNeeds.Job
	needs := job.Needs
	if slices.Contains(needs, requiredJob) {
		// Looks good, the needed job is listed in `needs`.  It's possible that the matrix may be incomplete by
		// referencing multiple different outputs, and not *all* outputs are in the job's `needs`... `requiredJob` will
		// only be the first one that was found while evaluating the matrix.  But as long as at least one job is listed
		// in `needs`, the job should be revisited by job_emitter and end up at a final resolution.
		return false, nil
	}

	// Job doesn't seem like it can proceed; mark the run with an error.
	if err := job.LoadRun(ctx); err != nil {
		return false, err
	}
	if err := FailRunPreExecutionError(ctx, job.Run, actions_model.ErrorCodeIncompleteMatrixMissingJob, []any{
		job.JobID,
		requiredJob,
		strings.Join(needs, ", "),
	}); err != nil {
		return false, err
	}

	return true, nil
}

func checkJobRunsOnStaticMatrixError(ctx context.Context, job *actions_model.ActionRunJob) (bool, error) {
	// If a job has a `runs-on` field that references a matrix dimension like `runs-on: ${{ matrix.platorm }}`, and
	// `platform` is not part of the job's matrix at all, then it will be tagged as `IsIncompleteRunsOn` and will be
	// blocked forever.  This only applies if the matrix is static -- that is, the job isn't also tagged
	// `IsIncompleteMatrix` and the matrix is yet to be fully defined.

	isIncompleteRunsOn, _, matrixReference, err := job.IsIncompleteRunsOn()
	if err != nil {
		return false, err
	} else if !isIncompleteRunsOn || matrixReference == nil {
		// Not incomplete, or, it's incomplete but not because of a matrix reference error.
		return false, nil
	}

	isIncompleteMatrix, _, err := job.IsIncompleteMatrix()
	if err != nil {
		return false, err
	} else if isIncompleteMatrix {
		// Not a static matrix, so this might be resolved later when the job is expanded.
		return false, nil
	}

	// Job doesn't seem like it can proceed; mark the run with an error.
	if err := job.LoadRun(ctx); err != nil {
		return false, err
	}
	if err := FailRunPreExecutionError(ctx, job.Run, actions_model.ErrorCodeIncompleteRunsOnMissingMatrixDimension, []any{
		job.JobID,
		matrixReference.Dimension,
	}); err != nil {
		return false, err
	}

	return true, nil
}
