import { useState } from 'react';
import type { ConfigResponse } from '../../../../../packages/api-contracts/src/index.js';
import {
  NumberField,
  RadioCards,
  SelectField,
  SwitchField,
  TextAreaField,
  TextField,
  type RadioCardOption,
} from '../../components/form-fields.js';
import { Modal } from '../../components/modal.js';
import { RiskDialog } from '../settings/risk-dialog.js';
import {
  conversationModes,
  createEmptySubredditDraft,
  formatShare,
  MAX_AUTOMATED_TURNS,
  previewShare,
  toSubredditDraft,
  usesAutomatedTurns,
  validateSubredditDraft,
  type ConversationMode,
  type SubredditConfig,
  type SubredditDraft,
} from './subreddit-model.js';

interface SubredditEditorProps {
  /** The subreddit being edited, or null to create a new one. */
  subreddit: SubredditConfig | null;
  allSubreddits: readonly SubredditConfig[];
  tones: ConfigResponse['tones'];
  isSaving: boolean;
  saveError: Error | null;
  onCancel(): void;
  onSave(config: SubredditConfig): void;
}

function errorMessage(error: Error | null): string {
  return error?.message ?? 'Something went wrong.';
}

/**
 * Edits exactly one subreddit. Because the draft is a single row, validation
 * errors are keyed by plain field name — there are no array indices to shift
 * when rows are added or removed elsewhere.
 */
export function SubredditEditor({
  allSubreddits,
  isSaving,
  onCancel,
  onSave,
  saveError,
  subreddit,
  tones,
}: SubredditEditorProps) {
  const isNew = subreddit === null;
  const [draft, setDraft] = useState<SubredditDraft>(() =>
    subreddit ? toSubredditDraft(subreddit) : createEmptySubredditDraft());
  const [errors, setErrors] = useState<Record<string, string>>({});
  const [pendingRisks, setPendingRisks] = useState<{ config: SubredditConfig; reasons: string[] } | null>(null);

  const takenNames = allSubreddits
    .filter((item) => item.name !== subreddit?.name)
    .map((item) => item.name);

  function update(next: Partial<SubredditDraft>) {
    setErrors({});
    setDraft((current) => ({ ...current, ...next }));
  }

  function submit() {
    const validation = validateSubredditDraft(draft, takenNames);
    setErrors(validation.errors);
    if (!validation.config) return;

    const reasons: string[] = [];
    const previousMode = subreddit?.conversation.mode;
    const nextMeta = conversationModes.find((mode) => mode.value === validation.config!.conversation.mode);
    if (nextMeta?.isAutonomous && previousMode !== validation.config.conversation.mode) {
      reasons.push(
        `r/${validation.config.name} will reply autonomously, without approval for each message.`
        + (validation.config.conversation.mode === 'r4r-media'
          ? ' After rapport it can make one optional, non-explicit image request.'
          : ' It will not request sexual media.'),
      );
      reasons.push('Conversations already in progress keep the policy they started with.');
    }

    if (reasons.length > 0) {
      setPendingRisks({ config: validation.config, reasons });
      return;
    }
    onSave(validation.config);
  }

  const share = previewShare(draft, allSubreddits, subreddit?.name ?? null);
  const turnOptions: RadioCardOption<ConversationMode>[] = conversationModes.map((mode) => ({
    value: mode.value,
    label: mode.label,
    description: mode.description,
    isRisky: mode.isAutonomous,
    detail: usesAutomatedTurns(mode.value) ? (
      <div className="field-row">
        <NumberField
          error={errors.maxAutomatedTurns}
          hint={`Replies it may send before handing over (1–${MAX_AUTOMATED_TURNS}).`}
          label="Maximum automated turns"
          max={MAX_AUTOMATED_TURNS}
          min={1}
          name="max-automated-turns"
          onChange={(maxAutomatedTurns) => update({ maxAutomatedTurns })}
          suffix="turns"
          value={draft.maxAutomatedTurns}
        />
        {mode.value === 'r4r-media' ? (
          <NumberField
            error={errors.rapportTurnsBeforeMediaAsk}
            hint="Must be lower than the maximum automated turns."
            label="Rapport turns before the ask"
            max={MAX_AUTOMATED_TURNS - 1}
            min={1}
            name="rapport-turns"
            onChange={(rapportTurnsBeforeMediaAsk) => update({ rapportTurnsBeforeMediaAsk })}
            suffix="turns"
            value={draft.rapportTurnsBeforeMediaAsk}
          />
        ) : null}
      </div>
    ) : undefined,
  }));

  return (
    <>
      <Modal className="drawer-card" isDismissLocked={isSaving} labelledBy="subreddit-editor-title" onClose={onCancel}>
        <header className="drawer-heading">
          <div>
            <span className="eyebrow">{isNew ? 'New subreddit' : 'Edit subreddit'}</span>
            <h2 id="subreddit-editor-title">{isNew ? 'Add a subreddit' : `r/${subreddit.name}`}</h2>
          </div>
          <button aria-label="Close editor" className="icon-button" disabled={isSaving} onClick={onCancel} type="button">
            <span aria-hidden="true">×</span>
          </button>
        </header>

        <div className="drawer-body">
          <fieldset className="field-group">
            <legend>Community</legend>
            <div className="field-row">
              <TextField
                error={errors.name}
                hint="Without the r/ prefix."
                label="Subreddit name"
                name="subreddit-name"
                onChange={(name) => update({ name })}
                placeholder="casualconversation"
                prefix="r/"
                value={draft.name}
              />
              <SelectField
                label="Post type"
                name="subreddit-type"
                onChange={(type) => update({ type })}
                options={[{ value: 'image', label: 'Image posts' }, { value: 'chat', label: 'Chat and text posts' }]}
                value={draft.type}
              />
              <SelectField
                hint="Comment mode scans reactions on each new image post and contacts only high-confidence matches."
                label="Recipient"
                name="subreddit-targeting-mode"
                onChange={(targetingMode) => update({ targetingMode })}
                options={draft.type === 'chat'
                  ? [{ value: 'post-author', label: 'Post author' }]
                  : [
                      { value: 'post-author', label: 'Post author' },
                      { value: 'comment-author', label: 'Qualifying commenter' },
                    ]}
                value={draft.type === 'chat' ? 'post-author' : draft.targetingMode}
              />
            </div>
          </fieldset>

          <fieldset className="field-group">
            <legend>Targeting</legend>
            <SwitchField
              checked={draft.enabled}
              description="Disabled subreddits are not polled at all and take no share of attention."
              label="Poll this subreddit"
              onChange={(enabled) => update({ enabled })}
            />
            <div className="field-row">
              <NumberField
                error={errors.weight}
                hint="Relative to other enabled subreddits. Leave blank for the default of 1."
                label="Weight"
                min={0.01}
                name="subreddit-weight"
                onChange={(weight) => update({ weight })}
                step="any"
                value={draft.weight}
              />
              {/* Weight only means something as a proportion, so show the
                  proportion it will actually produce. */}
              <div className="share-preview">
                <span className="field-label">Share of polling</span>
                <strong aria-live="polite">{formatShare(share)}</strong>
                <small>{draft.enabled ? 'Of all enabled subreddits, once saved.' : 'Nothing while polling is off.'}</small>
              </div>
            </div>
          </fieldset>

          <fieldset className="field-group">
            <legend>Voice</legend>
            <div className="field-row">
              <SelectField
                hint="Which tone profile writes the messages."
                label="Tone"
                name="subreddit-tone"
                onChange={(tone) => update({ tone })}
                options={tones.map((tone) => ({ value: tone, label: tone }))}
                value={draft.tone}
              />
            </div>
            <TextAreaField
              hint="Sent verbatim instead of a generated opener. Leave blank to let the model write it."
              label="Scripted opening message (optional)"
              name="subreddit-scripted"
              onChange={(scripted) => update({ scripted })}
              rows={3}
              value={draft.scripted}
            />
          </fieldset>

          <RadioCards
            legend="Conversation policy"
            name="conversation-mode"
            onChange={(conversationMode) => update({ conversationMode })}
            options={turnOptions}
            value={draft.conversationMode}
          />
        </div>

        <footer className="drawer-footer">
          <div aria-live="polite" className="settings-card-status">
            {Object.keys(errors).length > 0 ? (
              <strong className="save-error" role="alert">
                {Object.keys(errors).length === 1
                  ? 'Resolve 1 problem before saving.'
                  : `Resolve ${Object.keys(errors).length} problems before saving.`}
              </strong>
            ) : null}
            {saveError ? <strong className="save-error" role="alert">{errorMessage(saveError)}</strong> : null}
          </div>
          <div className="header-actions">
            <button className="button secondary" disabled={isSaving} onClick={onCancel} type="button">Cancel</button>
            <button
              aria-busy={isSaving ? 'true' : undefined}
              className="button primary"
              disabled={isSaving}
              onClick={submit}
              type="button"
            >
              {isSaving ? 'Saving…' : isNew ? 'Add subreddit' : 'Save subreddit'}
            </button>
          </div>
        </footer>
      </Modal>

      {pendingRisks ? (
        <RiskDialog
          isPending={isSaving}
          onCancel={() => setPendingRisks(null)}
          onConfirm={() => onSave(pendingRisks.config)}
          reasons={pendingRisks.reasons}
        />
      ) : null}
    </>
  );
}