import defaultRuntimeMap from '../runtime/token-to-css-var.json';
import { applyExpandedThemeOverride } from './adapters/uniwind';
import { DEFAULT_PRESET } from './constants';
import { expandThemeOverride } from './override/expand';
import type {
  AdapterWriteFailure,
  OverrideDiagnostic,
  RuntimeMap,
  UpdateCssVariables,
} from './override/contracts';
import type { Platform } from './types';

export type { UpdateCssVariables } from './override/contracts';
export { DEFAULT_PRESET };

export type ApplyThemeOverrideResult =
  | {
      readonly applied: true;
      readonly revision: string;
      readonly diagnostics: readonly OverrideDiagnostic[];
    }
  | {
      readonly applied: false;
      readonly reason: 'invalid_theme_override' | 'no_theme_changes';
      readonly diagnostics: readonly OverrideDiagnostic[];
      readonly revision: string;
    }
  | {
      readonly applied: false;
      readonly reason: 'adapter_write_failed';
      readonly diagnostics: readonly OverrideDiagnostic[];
      readonly revision: string;
      readonly failure: AdapterWriteFailure;
    };

export interface ApplyThemeOverrideOptions {
  runtimeMap?: RuntimeMap;
  runtimePlatform?: Platform;
  updateCSSVariables?: UpdateCssVariables;
}

export interface ApplyThemeOverrideRuntimeOptions {
  runtimeMap?: RuntimeMap;
  runtimePlatform: Platform;
  getUpdateCSSVariables: () => UpdateCssVariables;
}

export function applyThemeOverrideWithRuntime(
  override: unknown,
  options: ApplyThemeOverrideRuntimeOptions,
): ApplyThemeOverrideResult {
  const { runtimeMap = defaultRuntimeMap, runtimePlatform, getUpdateCSSVariables } = options;
  const expansion = expandThemeOverride(override, runtimePlatform);

  if (!expansion.valid) {
    return {
      applied: false,
      reason: 'invalid_theme_override',
      diagnostics: expansion.diagnostics,
      revision: expansion.revision.id,
    };
  }

  const { expanded } = expansion;
  if (
    Object.keys(expanded.writes.light).length === 0 &&
    Object.keys(expanded.writes.dark).length === 0
  ) {
    return {
      applied: false,
      reason: 'no_theme_changes',
      diagnostics: expanded.diagnostics,
      revision: expanded.revision.id,
    };
  }

  const application = applyExpandedThemeOverride({
    expanded,
    runtimeMap,
    writer: getUpdateCSSVariables(),
  });
  if (!application.applied) {
    return {
      applied: false,
      reason: 'adapter_write_failed',
      diagnostics: expanded.diagnostics,
      revision: expanded.revision.id,
      failure: application.failure,
    };
  }

  return {
    applied: true,
    revision: application.revision,
    diagnostics: expanded.diagnostics,
  };
}