/**
 * Capacity model (#8). A member's throughput is `focusFactor × allocation` =
 * ideal person-days of project work delivered per calendar working day. The
 * scheduler treats each member as a lane whose task durations are scaled by that
 * rate (a 0.5-capacity person takes twice as long on an est/2d task). Config
 * lives in the pm-state repo (`capacity/members.yaml/json`, D4); estimates are
 * in ideal person-days (pm-state.md).
 */

export interface CapacityMember {
  /** gitea login. */
  person: string
  /** Productive fraction of a working day (0..1). */
  focusFactor: number
  /** Fraction of that allocated to this project (0..1). */
  allocation: number
}

/** Ideal person-days delivered per calendar working day. */
export function capacityPerWorkday(m: CapacityMember): number {
  return m.focusFactor * m.allocation
}

function clamp01(n: unknown, fallback: number): number {
  return typeof n === 'number' && Number.isFinite(n) ? Math.min(1, Math.max(0, n)) : fallback
}

/**
 * Validate a raw capacity config (`{ members: [...] }`) into members. Unknown
 * shapes degrade to `[]` (→ the scheduler falls back to a single worker), never
 * throw. focusFactor/allocation clamp to [0,1]; a member without a person is dropped.
 */
export function parseCapacityConfig(raw: unknown): CapacityMember[] {
  const list = (raw as { members?: unknown })?.members
  if (!Array.isArray(list)) return []
  const out: CapacityMember[] = []
  for (const m of list) {
    const r = (m ?? {}) as Record<string, unknown>
    const person = typeof r.person === 'string' ? r.person.trim() : ''
    if (!person) continue
    const member: CapacityMember = {
      person,
      focusFactor: clamp01(r.focusFactor, 0.8),
      allocation: clamp01(r.allocation, 1),
    }
    if (capacityPerWorkday(member) > 0) out.push(member)
  }
  return out
}