name: channel vars

on:
  workflow_call:
    inputs:
      github_event_name:
        type: string
      github_ref_name:
        type: string
        required: false
      github_ref:
        type: string
        required: false
      workflow_dispatch_channel:
        type: string
        required: false
      workflow_dispatch_ref:
        type: string
        required: false

    outputs:
      channel:
        description: 'Computed release channel (stable|canary)'
        value: ${{ jobs.emit.outputs.channel }}
      is_canary:
        description: 'Whether this is a canary deploy (true|false)'
        value: ${{ jobs.emit.outputs.is_canary }}
      source_ref:
        description: 'Git ref to check out for the deploy'
        value: ${{ jobs.emit.outputs.source_ref }}
      stack_suffix:
        description: "Suffix for stack/image names ('' or '-canary')"
        value: ${{ jobs.emit.outputs.stack_suffix }}

jobs:
  emit:
    runs-on: ubuntu-latest
    outputs:
      channel: ${{ steps.compute.outputs.channel }}
      is_canary: ${{ steps.compute.outputs.is_canary }}
      source_ref: ${{ steps.compute.outputs.source_ref }}
      stack_suffix: ${{ steps.compute.outputs.stack_suffix }}
    steps:
      - name: Determine channel
        id: compute
        shell: bash
        run: |
          set -euo pipefail

          event_name="${{ inputs.github_event_name }}"
          ref_name="${{ inputs.github_ref_name || '' }}"
          ref="${{ inputs.github_ref || '' }}"
          dispatch_channel="${{ inputs.workflow_dispatch_channel || '' }}"
          dispatch_ref="${{ inputs.workflow_dispatch_ref || '' }}"

          channel="stable"
          if [[ "${event_name}" == "push" ]]; then
            if [[ "${ref_name}" == "canary" ]]; then
              channel="canary"
            fi
          else
            if [[ "${dispatch_channel}" == "canary" ]]; then
              channel="canary"
            fi
          fi

          if [[ "${event_name}" == "push" ]]; then
            source_ref="${ref:-refs/heads/${ref_name:-main}}"
          else
            if [[ -n "${dispatch_ref}" ]]; then
              source_ref="${dispatch_ref}"
            else
              if [[ "${channel}" == "canary" ]]; then
                source_ref="refs/heads/canary"
              else
                source_ref="refs/heads/main"
              fi
            fi
          fi

          stack_suffix=""
          if [[ "${channel}" == "canary" ]]; then
            stack_suffix="-canary"
          fi

          is_canary="false"
          if [[ "${channel}" == "canary" ]]; then
            is_canary="true"
          fi

          printf 'channel=%s\n' "${channel}" >> "$GITHUB_OUTPUT"
          printf 'is_canary=%s\n' "${is_canary}" >> "$GITHUB_OUTPUT"
          printf 'source_ref=%s\n' "${source_ref}" >> "$GITHUB_OUTPUT"
          printf 'stack_suffix=%s\n' "${stack_suffix}" >> "$GITHUB_OUTPUT"