feat: Filter Controls Job Matching (#414)

src/lib/jobMatchingFilters.ts

@@ -0,0 +1,119 @@
+/**
+ * Filter Controls: Job Matching (#414).
+ *
+ * Pure encoding of filter controls + a matchJobs() helper that ranks a list
+ * of postings against a candidate profile. Designed to be co-located with
+ * existing filter-component code without bringing in a heavy dependency.
+ */
+
+export interface JobPosting {
+  id: string;
+  title: string;
+  company: string;
+  skills: string[];
+  location: string;
+  remote: boolean;
+  salaryMin?: number;
+  salaryMax?: number;
+  postedAt: string; // ISO
+}
+
+export interface CandidateProfile {
+  skills: string[];
+  preferredLocations: string[];
+  openToRemote: boolean;
+  minSalary?: number;
+}
+
+export interface MatchingWeights {
+  skill: number;
+  location: number;
+  salary: number;
+  recency: number;
+}
+
+export const DEFAULT_WEIGHTS: MatchingWeights = {
+  skill: 0.5,
+  location: 0.2,
+  salary: 0.2,
+  recency: 0.1,
+};
+
+export interface JobQuery {
+  text?: string;
+  skills?: string[];
+  location?: string;
+  remoteOnly?: boolean;
+  minSalary?: number;
+}
+
+export function applyQuery(
+  postings: JobPosting[],
+  query: JobQuery,
+): JobPosting[] {
+  const text = query.text?.toLowerCase().trim();
+  const skillSet = new Set((query.skills ?? []).map((s) => s.toLowerCase()));
+  return postings.filter((j) => {
+    if (text && !`${j.title} ${j.company}`.toLowerCase().includes(text)) {
+      return false;
+    }
+    for (const s of skillSet) {
+      if (!j.skills.some((js) => js.toLowerCase() === s)) return false;
+    }
+    if (query.location && j.location !== query.location) return false;
+    if (query.remoteOnly && !j.remote) return false;
+    if (query.minSalary != null && (j.salaryMax ?? 0) < query.minSalary) {
+      return false;
+    }
+    return true;
+  });
+}
+
+interface ScoredJob {
+  job: JobPosting;
+  score: number;
+}
+
+export function matchJobs(
+  postings: JobPosting[],
+  candidate: CandidateProfile,
+  weights: MatchingWeights = DEFAULT_WEIGHTS,
+): JobPosting[] {
+  const candSkills = new Set(candidate.skills.map((s) => s.toLowerCase()));
+  const now = Date.now();
+
+  const scored: ScoredJob[] = postings.map((job) => {
+    const overlap = job.skills.filter((s) => candSkills.has(s.toLowerCase()));
+    const skillScore = candSkills.size === 0 ? 0 : overlap.length / candSkills.size;
+
+    const locMatch =
+      candidate.preferredLocations.includes(job.location) ||
+      (candidate.openToRemote && job.remote)
+        ? 1
+        : 0;
+
+    const salaryScore =
+      candidate.minSalary == null || job.salaryMax == null
+        ? 0.5
+        : job.salaryMax >= candidate.minSalary
+          ? 1
+          : 0;
+
+    const ageDays = Math.max(
+      1,
+      Math.floor((now - Date.parse(job.postedAt)) / 86_400_000),
+    );
+    const recencyScore = Math.max(0, 1 - ageDays / 60);
+
+    const score =
+      weights.skill * skillScore +
+      weights.location * locMatch +
+      weights.salary * salaryScore +
+      weights.recency * recencyScore;
+
+    return { job, score };
+  });
+
+  scored.sort((a, b) => b.score - a.score);
+  return scored.map((s) => s.job);
+}