// How a ClinicalTrials.gov v2 study is read into flat rows.

/** The parts of a study record this plugin reads, as the API answers them. */
export interface Study {
  protocolSection?: {
    identificationModule?: { nctId?: string; briefTitle?: string; officialTitle?: string }
    statusModule?: {
      overallStatus?: string
      startDateStruct?: { date?: string; type?: string }
      primaryCompletionDateStruct?: { date?: string; type?: string }
      completionDateStruct?: { date?: string; type?: string }
      studyFirstPostDateStruct?: { date?: string }
      resultsFirstPostDateStruct?: { date?: string }
      lastUpdatePostDateStruct?: { date?: string }
    }
    sponsorCollaboratorsModule?: {
      leadSponsor?: { name?: string; class?: string }
      collaborators?: { name?: string }[]
    }
    descriptionModule?: { briefSummary?: string }
    conditionsModule?: { conditions?: string[] }
    designModule?: {
      studyType?: string
      phases?: string[]
      designInfo?: { allocation?: string; primaryPurpose?: string; maskingInfo?: { masking?: string } }
      enrollmentInfo?: { count?: number; type?: string }
    }
    armsInterventionsModule?: {
      armGroups?: { label?: string; type?: string; interventionNames?: string[] }[]
      interventions?: { type?: string; name?: string }[]
    }
    outcomesModule?: { primaryOutcomes?: { measure?: string; timeFrame?: string }[] }
    eligibilityModule?: {
      eligibilityCriteria?: string
      sex?: string
      minimumAge?: string
      maximumAge?: string
      healthyVolunteers?: boolean
    }
    contactsLocationsModule?: { locations?: unknown[] }
  }
  hasResults?: boolean
}

export type Row = Record<string, string | number | boolean | null>

/** One flat row for a search result. */
export function summaryRow(study: Study): Row {
  const p = study.protocolSection ?? {}
  const id = p.identificationModule ?? {}
  const status = p.statusModule ?? {}
  const sponsors = p.sponsorCollaboratorsModule ?? {}
  const design = p.designModule ?? {}
  const nctId = id.nctId ?? ''
  return {
    nctId,
    briefTitle: id.briefTitle ?? null,
    leadSponsor: sponsors.leadSponsor?.name ?? null,
    sponsorClass: sponsors.leadSponsor?.class ?? null,
    collaborators: join(sponsors.collaborators?.map((c) => c.name)),
    phases: join(design.phases),
    overallStatus: status.overallStatus ?? null,
    startDate: status.startDateStruct?.date ?? null,
    primaryCompletionDate: status.primaryCompletionDateStruct?.date ?? null,
    primaryCompletionType: status.primaryCompletionDateStruct?.type ?? null,
    completionDate: status.completionDateStruct?.date ?? null,
    conditions: join(p.conditionsModule?.conditions),
    interventions: join(p.armsInterventionsModule?.interventions?.map((i) => (i.type ? `${i.type}: ${i.name}` : i.name))),
    enrollment: design.enrollmentInfo?.count ?? null,
    studyType: design.studyType ?? null,
    hasResults: study.hasResults ?? false,
    lastUpdatePostDate: status.lastUpdatePostDateStruct?.date ?? null,
    url: `https://clinicaltrials.gov/study/${nctId}`,
  }
}

/** The summary row plus the key details of one study. */
export function detailRow(study: Study): Row {
  const p = study.protocolSection ?? {}
  const status = p.statusModule ?? {}
  const design = p.designModule ?? {}
  const elig = p.eligibilityModule ?? {}
  return {
    ...summaryRow(study),
    officialTitle: p.identificationModule?.officialTitle ?? null,
    briefSummary: p.descriptionModule?.briefSummary ?? null,
    primaryOutcomes: join(
      p.outcomesModule?.primaryOutcomes?.map((o) => (o.timeFrame ? `${o.measure} [${o.timeFrame}]` : o.measure)),
      ' | ',
    ),
    arms: join(
      p.armsInterventionsModule?.armGroups?.map(
        (a) => `${a.label}${a.type ? ` (${a.type})` : ''}${a.interventionNames?.length ? `: ${a.interventionNames.join(', ')}` : ''}`,
      ),
      ' | ',
    ),
    allocation: design.designInfo?.allocation ?? null,
    masking: design.designInfo?.maskingInfo?.masking ?? null,
    primaryPurpose: design.designInfo?.primaryPurpose ?? null,
    enrollmentType: design.enrollmentInfo?.type ?? null,
    sex: elig.sex ?? null,
    minimumAge: elig.minimumAge ?? null,
    maximumAge: elig.maximumAge ?? null,
    healthyVolunteers: elig.healthyVolunteers ?? null,
    eligibilityCriteria: elig.eligibilityCriteria ? elig.eligibilityCriteria.slice(0, 4000) : null,
    locationsCount: p.contactsLocationsModule?.locations?.length ?? 0,
    startDateType: status.startDateStruct?.type ?? null,
    completionDateType: status.completionDateStruct?.type ?? null,
    studyFirstPostDate: status.studyFirstPostDateStruct?.date ?? null,
    resultsFirstPostDate: status.resultsFirstPostDateStruct?.date ?? null,
  }
}

/** A list as one string, or null when empty. */
function join(items: (string | undefined)[] | undefined, separator = '; '): string | null {
  const kept = (items ?? []).filter((s): s is string => Boolean(s))
  return kept.length ? kept.join(separator) : null
}