import React from 'react';
import { Sparkles, Upload } from 'lucide-react';
import { Button, Field, Input, Modal, Textarea, toast } from '@/components/ds';
import { usePreferences, useUpdatePreferences } from '@/lib/krowHooks';
import { PAGE_KEYS, validateSkillSource } from '@/lib/skills/registry';
import { skillTemplate, upsertCustomSkill } from '@/lib/skills/customSkills';

/**
 * Add an Owliver skill.
 *
 * One dialog, opened from Settings and from Owliver's own header, writing to
 * one registry — a second registration path would be a second source of truth
 * by another name.
 *
 * What is stored is the Markdown itself, not a parsed record. A custom skill is
 * then exactly the artefact a file on disk is, read by the same parser, and can
 * be copied into `src/skills/` later without conversion.
 *
 * The fields above the editor are a starting point, not a second schema: typing
 * in them composes frontmatter in the existing format, which the author can
 * then edit directly. The Markdown is always what gets saved.
 */

export function AddSkillDialog({ open, onOpenChange }) {
  const preferences = usePreferences();
  const updatePreferences = useUpdatePreferences();

  const [meta, setMeta] = React.useState({ id: '', name: '', description: '', pages: '' });
  const [source, setSource] = React.useState('');
  const [touched, setTouched] = React.useState(false);
  const [error, setError] = React.useState('');
  const fileRef = React.useRef(null);

  /* A fresh sheet each time it opens, so an abandoned draft is not waiting the
     next time someone adds a skill. */
  React.useEffect(() => {
    if (!open) return;
    setMeta({ id: '', name: '', description: '', pages: '' });
    setSource('');
    setTouched(false);
    setError('');
  }, [open]);

  /* The fields drive the Markdown until the author edits the Markdown, after
     which the Markdown wins — it is the thing being saved. */
  const syncFromMeta = (next) => {
    setMeta(next);
    if (touched) return;
    setSource(skillTemplate({
      id: next.id,
      name: next.name,
      description: next.description,
      pages: next.pages.split(',').map((p) => p.trim()).filter(Boolean),
    }));
  };

  const readFile = (event) => {
    const file = event.target.files?.[0];
    if (!file) return;
    const reader = new FileReader();
    reader.onload = () => {
      setSource(String(reader.result));
      setTouched(true);
      setError('');
    };
    reader.readAsText(file);
    event.target.value = '';
  };

  const save = () => {
    const problem = validateSkillSource(source);
    if (problem) {
      setError(problem);
      return;
    }

    const { skill, next } = upsertCustomSkill(preferences.customSkills || [], source);

    updatePreferences.mutate({ customSkills: next });
    toast.success(`${skill.name} added`);
    onOpenChange(false);
  };

  return (
    <Modal
      open={open}
      onOpenChange={onOpenChange}
      title="Add Owliver skill"
      description="Define a skill in Markdown. It attaches itself to the pages it names."
      icon={Sparkles}
      size="lg"
      footer={
        <>
          <Button variant="outline" onClick={() => onOpenChange(false)}>Cancel</Button>
          <Button onClick={save} loading={updatePreferences.isPending}>Add skill</Button>
        </>
      }
    >
      <div className="space-y-4">
        <div className="grid gap-4 sm:grid-cols-2">
          <Field label="Skill name">
            <Input
              value={meta.name}
              placeholder="Chef Training"
              onChange={(e) => syncFromMeta({ ...meta, name: e.target.value })}
            />
          </Field>
          <Field label="Skill ID" hint="Lower-case, dashes.">
            <Input
              value={meta.id}
              placeholder="chef-training"
              onChange={(e) => syncFromMeta({ ...meta, id: e.target.value })}
            />
          </Field>
        </div>

        <Field label="Description">
          <Input
            value={meta.description}
            placeholder="Helps Owliver explain chef training paths."
            onChange={(e) => syncFromMeta({ ...meta, description: e.target.value })}
          />
        </Field>

        <Field label="Pages" hint={`Comma separated. Known pages: ${PAGE_KEYS.join(', ')}`}>
          <Input
            value={meta.pages}
            placeholder="university"
            onChange={(e) => syncFromMeta({ ...meta, pages: e.target.value })}
          />
        </Field>

        <Field
          label="Markdown definition"
          hint="This is what gets saved. Edit it directly if you prefer."
          error={error}
        >
          <Textarea
            value={source}
            rows={12}
            spellCheck={false}
            className="font-mono text-[12px] leading-relaxed"
            placeholder="---&#10;id: my-skill&#10;name: My Skill&#10;pages:&#10;  - positions&#10;---"
            onChange={(e) => {
              setSource(e.target.value);
              setTouched(true);
              if (error) setError('');
            }}
          />
        </Field>

        <div className="flex items-center gap-2">
          <input ref={fileRef} type="file" accept=".md,text/markdown" onChange={readFile} className="hidden" />
          <Button variant="outline" size="sm" onClick={() => fileRef.current?.click()}>
            <Upload aria-hidden="true" /> Upload .md
          </Button>
          <p className="text-caption text-ink-4">Markdown is stored as data. It is never executed.</p>
        </div>
      </div>
    </Modal>
  );
}