import { kebabCase, pascalCase } from 'scule'
import type { Component, ComponentsDir } from '@nuxt/schema'
import { useNuxt } from './context'
import { assertNuxtCompatibility } from './compatibility'
import { logger } from './logger'

/**
 * Register a directory to be scanned for components and imported only when used.
 *
 * Requires Nuxt 2.13+
 */
export async function addComponentsDir (dir: ComponentsDir, opts: { prepend?: boolean } = {}) {
  const nuxt = useNuxt()
  await assertNuxtCompatibility({ nuxt: '>=2.13' }, nuxt)
  nuxt.options.components = nuxt.options.components || []
  dir.priority ||= 0
  nuxt.hook('components:dirs', (dirs) => { dirs[opts.prepend ? 'unshift' : 'push'](dir) })
}

export type AddComponentOptions = { name: string, filePath: string } & Partial<Exclude<Component,
'shortPath' | 'async' | 'level' | 'import' | 'asyncImport'
>>

/**
 * Register a component by its name and filePath.
 *
 * Requires Nuxt 2.13+
 */
export async function addComponent (opts: AddComponentOptions) {
  const nuxt = useNuxt()
  await assertNuxtCompatibility({ nuxt: '>=2.13' }, nuxt)
  nuxt.options.components = nuxt.options.components || []

  if (!opts.mode) {
    const [, mode = 'all'] = opts.filePath.match(/\.(server|client)(\.\w+)*$/) || []
    opts.mode = mode as 'all' | 'client' | 'server'
  }

  // Apply defaults
  const component: Component = {
    export: opts.export || 'default',
    chunkName: 'components/' + kebabCase(opts.name),
    global: opts.global ?? false,
    kebabName: kebabCase(opts.name || ''),
    pascalName: pascalCase(opts.name || ''),
    prefetch: false,
    preload: false,
    mode: 'all',
    shortPath: opts.filePath,
    priority: 0,
    meta: {},
    ...opts,
  }

  nuxt.hook('components:extend', (components: Component[]) => {
    const existingComponentIndex = components.findIndex(c => (c.pascalName === component.pascalName || c.kebabName === component.kebabName) && c.mode === component.mode)
    if (existingComponentIndex !== -1) {
      const existingComponent = components[existingComponentIndex]!
      const existingPriority = existingComponent.priority ?? 0
      const newPriority = component.priority ?? 0

      if (newPriority < existingPriority) { return }

      // We override where new component priority is equal or higher
      // but we warn if they are equal.
      if (newPriority === existingPriority) {
        const name = existingComponent.pascalName || existingComponent.kebabName
        logger.warn(`Overriding ${name} component. You can specify a \`priority\` option when calling \`addComponent\` to avoid this warning.`)
      }
      components.splice(existingComponentIndex, 1, component)
    } else {
      components.push(component)
    }
  })
}