Add SMAPI build workflow

.github/workflows/build-smapi.yml

@@ -0,0 +1,147 @@
+name: Build SMAPI
+
+on:
+    push:
+        tags:
+            - "[0-9]+.[0-9]+.[0-9]+" # On any d.d.d tag push.
+        branches:
+            - develop
+
+jobs:
+    build_and_release:
+        runs-on: ubuntu-latest
+        permissions:
+            contents: write # For creating releases.
+            id-token: write # For creating attestations.
+            attestations: write 
+        steps:
+            -   name: Checkout code
+                uses: actions/checkout@v4
+                with:
+                    fetch-depth: 0
+
+            -   name: Get trigger type. 
+                id: trigger-type # Possible values: tag, dev-branch.
+                run: |
+                    # If we ever decide to add manual workflow runs, this will need to be reworked.
+
+                    if [[ "${{ github.ref_type }}" == "tag" ]]; then
+                        echo "Building regular release."
+                        echo "trigger_type=tag" >> $GITHUB_OUTPUT
+                    elif [[ "${{ github.ref_name }}" == "develop" ]]; then
+                        echo "Building in-development release."
+                        echo "trigger_type=dev-branch" >> $GITHUB_OUTPUT
+                    else                        
+                        echo "Ran into an unexpected trigger type. Aborting."
+                        echo "Debug info:"
+                        echo "ref_type: ${{ github.ref_type }}"
+                        echo "ref_name: ${{ github.ref_name }}"
+
+                        exit 1
+                    fi
+
+            -   name: Extract current SMAPI version.
+                id: smapi-version
+                run: |
+                    version=$(pwsh -Command "([xml](Get-Content build/common.targets)).Project.PropertyGroup.Version")
+                    pattern="^([0-9]+)\.([0-9]+)\.([0-9]+)$"
+
+                    if [[ "$version" =~ $pattern ]]; then
+                        MAJOR="${BASH_REMATCH[1]}"
+                        MINOR="${BASH_REMATCH[2]}"
+                        PATCH="${BASH_REMATCH[3]}"
+                    else
+                        echo "Input semver did not match the strict x.y.z format. Aborting."
+                        echo "Debug info:"
+                        echo "Extracted version: $version"
+
+                        exit 1
+                    fi
+
+                    echo "smapi_version=$version" >> $GITHUB_OUTPUT
+                    echo "smapi_major=$MAJOR" >> $GITHUB_OUTPUT
+                    echo "smapi_minor=$MINOR" >> $GITHUB_OUTPUT
+                    echo "smapi_patch=$PATCH" >> $GITHUB_OUTPUT
+                    echo "VERSION=$MAJOR.$MINOR.$PATCH" >> $GITHUB_ENV
+                    echo "Version: $MAJOR.$MINOR.$PATCH"
+
+            -   name: Verify SMAPI version matches tag.
+                if: steps.trigger-type.outputs.trigger_type == 'tag'
+                run: |
+                    if [[ "$VERSION" != "${{ github.ref_name }}" ]]; then
+                        echo "The pushed tag doesn't match the version we have in build/common.targets. Aborting."
+                        echo "Debug info: "
+                        echo "Tag: ${{ github.ref_name }}"
+                        echo "In common.targets: $VERSION"
+
+                        exit 1
+                    fi
+
+            -   name: Update SMAPI's current version for dev builds.
+                id: version-parsing 
+                if: steps.trigger-type.outputs.trigger_type == 'dev-branch'
+                run: |
+                    updated_patch=$((${{steps.smapi-version.outputs.smapi_patch}} + 1))
+                    date=$(date +"%Y%m%d")
+                    updated_version=${{steps.smapi-version.outputs.smapi_major}}.${{steps.smapi-version.outputs.smapi_minor}}.$updated_patch-alpha.$date
+                    echo "VERSION=$updated_version" >> $GITHUB_ENV
+
+                    echo "This is a dev version. Building as version: $updated_version"
+
+                    build/unix/set-smapi-version.sh "$updated_version"
+                    echo "Version updated using build/unix/set-smapi-version.sh."
+
+            -   name: Checkout reference assemblies
+                uses: actions/checkout@v4
+                with:
+                    repository: "StardewModders/mod-reference-assemblies"
+                    path: "stardew-reference-assemblies"
+                    fetch-depth: 1
+
+            -   name: Symlink reference assemblies to a valid location. # Simply cloning the repo to this location doesn't seem to work.
+                run: |
+                    ln -s "$(pwd)/stardew-reference-assemblies" "$HOME/StardewValley"
+
+            -   name: Build SMAPI.
+                run: |
+                    echo "Building SMAPI $VERSION."
+                    build/unix/prepare-install-package.sh "$VERSION"
+
+            -   name: Rename build zips.
+                run: |
+                    mv "bin/SMAPI ${{ env.VERSION }} installer.zip" "bin/SMAPI-${{ env.VERSION }}-installer.zip"
+                    mv "bin/SMAPI ${{ env.VERSION }} installer for developers.zip" "bin/SMAPI-${{ env.VERSION }}-installer-for-developers.zip"
+
+            -   name: Upload regular installer.
+                uses: actions/upload-artifact@v4
+                with:
+                    name: 'SMAPI ${{ env.VERSION }} installer'
+                    path: 'bin/SMAPI-${{ env.VERSION }}-installer.zip'
+                    if-no-files-found: 'error'
+
+            -   name: Upload installer for developers.
+                uses: actions/upload-artifact@v4
+                with:
+                    name: "SMAPI ${{ env.VERSION }} installer for developers"
+                    path: "bin/SMAPI-${{ env.VERSION }}-installer-for-developers.zip"
+                    if-no-files-found: 'error'
+
+            -   name: Create release and upload artifact
+                uses: ncipollo/release-action@v1
+                if: steps.trigger-type.outputs.trigger_type == 'tag'
+                with:
+                    artifacts: "bin/SMAPI-${{ env.VERSION }}*.zip"
+                    token: ${{ secrets.GITHUB_TOKEN }}
+                    tag: ${{ github.ref_name }}
+                    name: "${{ env.VERSION }}"
+                    body: |
+                        Draft.
+                    draft: true
+
+            -   name: Generate artifact attestations
+                uses: actions/attest-build-provenance@v2
+                id: attestation-step
+                with:
+                    subject-path: |
+                        bin/SMAPI-${{ env.VERSION }}-installer.zip
+                        bin/SMAPI-${{ env.VERSION }}-installer-for-developers.zip