1 files changed, 134 insertions, 0 deletions
diff --git a/app/assets/javascripts/jira_connect/branches/components/source_branch_dropdown.vue b/app/assets/javascripts/jira_connect/branches/components/source_branch_dropdown.vue
new file mode 100644
index 00000000000..0e2d8821f36
--- /dev/null
+++ b/app/assets/javascripts/jira_connect/branches/components/source_branch_dropdown.vue
@@ -0,0 +1,134 @@
+<script>
+import { GlDropdown, GlDropdownItem, GlSearchBoxByType, GlLoadingIcon } from '@gitlab/ui';
+import { __ } from '~/locale';
+import { BRANCHES_PER_PAGE } from '../constants';
+import getProjectQuery from '../graphql/queries/get_project.query.graphql';
+
+export default {
+  BRANCHES_PER_PAGE,
+  components: {
+    GlDropdown,
+    GlDropdownItem,
+    GlSearchBoxByType,
+    GlLoadingIcon,
+  },
+  props: {
+    selectedProject: {
+      type: Object,
+      required: false,
+      default: null,
+    },
+    selectedBranchName: {
+      type: String,
+      required: false,
+      default: null,
+    },
+  },
+  data() {
+    return {
+      sourceBranchSearchQuery: '',
+      initialSourceBranchNamesLoading: false,
+      sourceBranchNamesLoading: false,
+      sourceBranchNames: [],
+    };
+  },
+  computed: {
+    hasSelectedProject() {
+      return Boolean(this.selectedProject);
+    },
+    hasSelectedSourceBranch() {
+      return Boolean(this.selectedBranchName);
+    },
+    branchDropdownText() {
+      return this.selectedBranchName || __('Select a branch');
+    },
+  },
+  watch: {
+    selectedProject: {
+      immediate: true,
+      async handler(selectedProject) {
+        if (!selectedProject) return;
+
+        this.initialSourceBranchNamesLoading = true;
+        await this.fetchSourceBranchNames({ projectPath: selectedProject.fullPath });
+        this.initialSourceBranchNamesLoading = false;
+      },
+    },
+  },
+  methods: {
+    onSourceBranchSelect(branchName) {
+      this.$emit('change', branchName);
+    },
+    onSourceBranchSearchQuery(branchSearchQuery) {
+      this.branchSearchQuery = branchSearchQuery;
+      this.fetchSourceBranchNames({
+        projectPath: this.selectedProject.fullPath,
+        searchPattern: this.branchSearchQuery,
+      });
+    },
+    onError({ message } = {}) {
+      this.$emit('error', { message });
+    },
+    async fetchSourceBranchNames({ projectPath, searchPattern } = {}) {
+      this.sourceBranchNamesLoading = true;
+      try {
+        const { data } = await this.$apollo.query({
+          query: getProjectQuery,
+          variables: {
+            projectPath,
+            branchNamesLimit: this.$options.BRANCHES_PER_PAGE,
+            branchNamesOffset: 0,
+            branchNamesSearchPattern: searchPattern ? `*${searchPattern}*` : '*',
+          },
+        });
+
+        const { branchNames, rootRef } = data?.project.repository || {};
+        this.sourceBranchNames = branchNames || [];
+
+        // Use root ref as the default selection
+        if (rootRef && !this.hasSelectedSourceBranch) {
+          this.onSourceBranchSelect(rootRef);
+        }
+      } catch (err) {
+        this.onError({
+          message: __('Something went wrong while fetching source branches.'),
+        });
+      } finally {
+        this.sourceBranchNamesLoading = false;
+      }
+    },
+  },
+};
+</script>
+
+<template>
+  <gl-dropdown
+    :text="branchDropdownText"
+    :loading="initialSourceBranchNamesLoading"
+    :disabled="!hasSelectedProject"
+    :class="{ 'gl-font-monospace': hasSelectedSourceBranch }"
+  >
+    <template #header>
+      <gl-search-box-by-type
+        :debounce="250"
+        :value="sourceBranchSearchQuery"
+        @input="onSourceBranchSearchQuery"
+      />
+    </template>
+
+    <gl-loading-icon v-show="sourceBranchNamesLoading" />
+    <template v-if="!sourceBranchNamesLoading">
+      <gl-dropdown-item
+        v-for="branchName in sourceBranchNames"
+        v-show="!sourceBranchNamesLoading"
+        :key="branchName"
+        :is-checked="branchName === selectedBranchName"
+        is-check-item
+        class="gl-font-monospace"
+        @click="onSourceBranchSelect(branchName)"
+      >
+        {{ branchName }}
+      </gl-dropdown-item>
+    </template>
+  </gl-dropdown>
+</template>