import { resolveAyanamsa } from "./ayanamsa.ts";
import { birthCalendarDate } from "./effective-birth-date.ts";
import { globalBirthProfileFromAccountRow } from "./server-owned-birth-profile.ts";
import { recordOrEmpty as record } from "@/lib/guards";

export const CHART_BIRTH_FAILURE_REASONS = [
  "profile_query_error",
  "profile_incomplete",
  "adopted_calculation_incomplete",
  "timezone_resolver_failure",
  "engine_busy",
  "engine_timeout",
  "engine_bad_payload",
  "engine_http_error",
  "response_schema_failure",
] as const;

export type ChartBirthFailureReason = (typeof CHART_BIRTH_FAILURE_REASONS)[number];

export type ChartBirthAdoption = "adopted" | "legacy" | "declared" | "incomplete";

export type ServerOwnedChartBirth = {
  status: string | null;
  date: string | null;
  time: string | null;
  timezoneOffset: number | null;
  timezoneId: string | null;
  provenance: unknown;
  reportedTime: string | null;
  activeTime: string | null;
  activeDate: string | null;
  declaredDate: string | null;
  fingerprint: string;
  chartable: boolean;
  failure: ChartBirthFailureReason | null;
  adoption: ChartBirthAdoption;
};

const ADOPTION_CLEAR_KEYS = [
  "birth_date",
  "reported_birth_time",
  "birth_time_source",
  "birth_time_period",
  "declared_window_start",
  "declared_window_end",
  "uncertainty_before_minutes",
  "uncertainty_after_minutes",
  "latitude",
  "longitude",
  "timezone_id",
  "timezone_offset",
] as const;

function text(value: unknown): string | null {
  if (typeof value !== "string") return null;
  const trimmed = value.trim();
  return trimmed.length > 0 ? trimmed : null;
}

function clock(value: unknown): string | null {
  const raw = text(value);
  if (!raw) return null;
  return raw.slice(0, 5);
}

function finite(value: unknown): number | null {
  if (typeof value === "number" && Number.isFinite(value)) return Object.is(value, -0) ? 0 : value;
  if (typeof value === "string" && value.trim()) {
    const parsed = Number(value);
    return Number.isFinite(parsed) ? parsed : null;
  }
  return null;
}

function canonical(value: unknown, depth = 0): string {
  if (depth > 8 || value == null) return "";
  if (typeof value === "number") return Number.isFinite(value) ? String(Object.is(value, -0) ? 0 : value) : "";
  if (typeof value === "string") return value;
  if (typeof value === "boolean") return value ? "1" : "0";
  if (Array.isArray(value)) return `[${value.map((item) => canonical(item, depth + 1)).join(",")}]`;
  if (typeof value === "object") {
    const entries = Object.keys(value as Record<string, unknown>).sort();
    return `{${entries.map((key) => `${key}:${canonical((value as Record<string, unknown>)[key], depth + 1)}`).join(",")}}`;
  }
  return "";
}

function fingerprintOf(parts: Record<string, unknown>): string {
  const textValue = canonical(parts);
  let out = "";
  for (const seed of [0x811c9dc5, 0x01000193, 0x9e3779b9, 0x85ebca6b]) {
    let hash = seed >>> 0;
    for (let index = 0; index < textValue.length; index += 1) {
      hash ^= textValue.charCodeAt(index);
      hash = Math.imul(hash, 0x01000193);
    }
    out += (hash >>> 0).toString(16).padStart(8, "0");
  }
  return out;
}

function comparable(key: string, value: unknown): unknown {
  if (key === "birth_date" || key === "active_birth_date") return birthCalendarDate(value) ?? null;
  if (key.endsWith("_time") || key.endsWith("_start") || key.endsWith("_end")) return clock(value);
  if (key === "latitude" || key === "longitude" || key === "timezone_offset" || key.endsWith("_minutes")) {
    return finite(value);
  }
  if (key === "active_birth_provenance") return canonical(value);
  return value ?? null;
}

function isDistinct(key: string, left: unknown, right: unknown): boolean {
  return comparable(key, left) !== comparable(key, right);
}

function emptyBirth(failure: ChartBirthFailureReason): ServerOwnedChartBirth {
  return {
    status: null,
    date: null,
    time: null,
    timezoneOffset: null,
    timezoneId: null,
    provenance: null,
    reportedTime: null,
    activeTime: null,
    activeDate: null,
    declaredDate: null,
    fingerprint: fingerprintOf({ failure }),
    chartable: false,
    failure,
    adoption: "incomplete",
  };
}

export function unresolvedChartBirth(failure: ChartBirthFailureReason): ServerOwnedChartBirth {
  return emptyBirth(failure);
}

/**
 * Mirrors `public.guard_adopted_birth_date`. Date, offset, and provenance
 * clear together. This never clears `active_birth_time`.
 */
export function applyAdoptedBirthDateGuard<T extends Record<string, unknown>>(
  previous: T | null,
  next: T,
): T {
  const status = next.birth_time_status;
  const statusUnusable = status == null || (status !== "accepted" && status !== "confirmed");
  const activeTimeMissing = next.active_birth_time == null || next.active_birth_time === "";
  const declarationChanged = previous != null && ADOPTION_CLEAR_KEYS.some((key) => (
    isDistinct(key, next[key], previous[key])
  ));
  const activeTimeChangedWithoutProvenance = previous != null
    && isDistinct("active_birth_time", next.active_birth_time, previous.active_birth_time)
    && !isDistinct("active_birth_provenance", next.active_birth_provenance, previous.active_birth_provenance);
  if (statusUnusable || activeTimeMissing || declarationChanged || activeTimeChangedWithoutProvenance) {
    return {
      ...next,
      active_birth_date: null,
      active_birth_timezone_offset: null,
      active_birth_provenance: null,
    };
  }
  return next;
}

export function resolveServerOwnedChartBirth(row: unknown): ServerOwnedChartBirth {
  const source = record(row);
  const status = text(source.birth_time_status);
  const declaredDate = birthCalendarDate(source.birth_date) ?? null;
  const activeDate = birthCalendarDate(source.active_birth_date) ?? null;
  const reportedTime = clock(source.reported_birth_time);
  const activeTime = clock(source.active_birth_time) ?? clock(source.birth_time);
  const timezoneId = text(source.timezone_id);
  const provenance = source.active_birth_provenance ?? null;
  const name = text(source.name);
  const latitude = finite(source.latitude);
  const longitude = finite(source.longitude);
  const ayanamsa = resolveAyanamsa(source);
  let profile: ReturnType<typeof globalBirthProfileFromAccountRow> | null = null;
  let failure: ChartBirthFailureReason | null = null;
  try {
    profile = globalBirthProfileFromAccountRow(row);
  } catch (error) {
    if (error instanceof Error && error.message === "adopted_birth_calculation_incomplete") {
      failure = "adopted_calculation_incomplete";
    } else {
      throw error;
    }
  }
  const usable = status === "accepted" || status === "confirmed";
  const date = failure ? null : profile?.date ?? null;
  const time = failure ? null : profile?.time ?? null;
  // An incomplete adopted tuple must not fall back to the declared offset.
  const timezoneOffset = failure
    ? null
    : typeof profile?.timezoneOffset === "number" && Number.isFinite(profile.timezoneOffset)
      ? profile.timezoneOffset
      : null;
  let adoption: ChartBirthAdoption = "declared";
  if (failure === "adopted_calculation_incomplete") adoption = "incomplete";
  else if (usable && activeDate) adoption = "adopted";
  else if (usable) adoption = "legacy";
  if (!failure && (date == null || time == null || timezoneOffset == null || latitude == null || longitude == null)) {
    failure = "profile_incomplete";
  }
  return {
    status,
    date,
    time,
    timezoneOffset,
    timezoneId,
    provenance,
    reportedTime,
    activeTime,
    activeDate,
    declaredDate,
    fingerprint: fingerprintOf({
      name,
      status,
      date,
      time,
      timezoneOffset,
      timezoneId,
      provenance,
      reportedTime,
      activeTime,
      activeDate,
      declaredDate,
      latitude,
      longitude,
      ayanamsa,
      failure,
    }),
    chartable: failure == null,
    failure,
    adoption,
  };
}

export function chartBirthAfterAccountWrite(input: {
  current: unknown;
  written: unknown;
  returned: unknown;
}): ServerOwnedChartBirth {
  const current = input.current == null ? null : record(input.current);
  const written = record(input.written);
  const returned = input.returned == null ? null : record(input.returned);
  const merged = {
    ...(current ?? {}),
    ...written,
    ...(returned ?? {}),
  };
  const databaseAlreadyJudgedAdoption = returned != null && (
    "active_birth_date" in returned
    || "active_birth_timezone_offset" in returned
    || "active_birth_provenance" in returned
  );
  const row = databaseAlreadyJudgedAdoption
    ? merged
    : applyAdoptedBirthDateGuard(current, merged);
  return resolveServerOwnedChartBirth(row);
}

export function readChartBirthFingerprint(value: unknown): string | null {
  if (!value || typeof value !== "object" || !("chartBirth" in value)) return null;
  const chartBirth = (value as { chartBirth?: { fingerprint?: unknown } }).chartBirth;
  return chartBirth && typeof chartBirth.fingerprint === "string" && chartBirth.fingerprint
    ? chartBirth.fingerprint
    : null;
}