export interface Configuration {
  max_tags_to_fetch: number
  max_pull_requests: number
  max_back_track_time_days: number
  exclude_merge_branches: string[]
  sort: Sort | string // "ASC" or "DESC"
  template: string
  pr_template: string
  empty_template: string
  categories: Category[]
  ignore_labels: string[]
  label_extractor: Extractor[]
  duplicate_filter?: Extractor // extract an identifier from a PR used to detect duplicates, will keep the last match (depends on `sort`)
  transformers: Transformer[]
  tag_resolver: TagResolver
  base_branches: string[]
  custom_placeholders?: Placeholder[]
}

export interface Category {
  title: string // the title of this category
  labels: string[] // labels to associate PRs to this category
  exclude_labels?: string[] // if an exclude label is detected, the PR will be excluded from this category
  exhaustive?: boolean // requires all labels to be present in the PR
  empty_content?: string // if the category has no matching PRs, this content will be used. If not set, the category will be skipped in the changelog.
}

export interface Sort {
  order: 'ASC' | 'DESC' // the sorting order
  on_property: 'mergedAt' | 'title' // the property to sort on. (mergedAt falls back to createdAt)
}

export interface Regex {
  pattern: string // the regex pattern to match
  flags?: string // the regex flag to use for RegExp
}

export interface Transformer extends Regex {
  target?: string // the target string to transform the source string using the regex to
}

export interface Extractor extends Transformer {
  on_property?: ('title' | 'author' | 'milestone' | 'body' | 'branch')[] | 'title' | 'author' | 'milestone' | 'body' | 'branch' | undefined // retrieve the property to extract the value from
  method?: 'replace' | 'match' | undefined // the method to use to extract the value, `match` will not use the `target` property
  on_empty?: string | undefined // in case the regex results in an empty string, this value is gonna be used instead (only for label_extractor currently)
}

export interface TagResolver {
  method: string // semver, sort
  filter?: Regex // the regex to filter the tags, prior to sorting
  transformer?: Transformer // transforms the tag name using the regex, run after the filter
}

export interface Placeholder {
  name: string // the name of the new placeholder
  source: string // the src placeholder which will be used to apply the transformer on
  transformer: Transformer // the transformer to use to transform the original placeholder into the custom placheolder
}

export const DefaultConfiguration: Configuration = {
  max_tags_to_fetch: 200, // the amount of tags to fetch from the github API
  max_pull_requests: 200, // the amount of pull requests to process
  max_back_track_time_days: 365, // allow max of 365 days back to check up on pull requests
  exclude_merge_branches: [], // branches to exclude from counting as PRs (e.g. YourOrg/qa, YourOrg/main)
  sort: {
    // defines the sorting logic for PRs
    order: 'ASC', // the sorting order
    on_property: 'mergedAt' // the property to sort on. (mergedAt falls back to createdAt)
  },
  template: '${{CHANGELOG}}', // the global template to host the changelog
  pr_template: '- ${{TITLE}}\n   - PR: #${{NUMBER}}', // the per PR template to pick
  empty_template: '- no changes', // the template to use if no pull requests are found
  categories: [
    {
      title: '## 🚀 Features',
      labels: ['feature']
    },
    {
      title: '## 🐛 Fixes',
      labels: ['fix']
    },
    {
      title: '## 🧪 Tests',
      labels: ['test']
    }
  ], // the categories to support for the ordering
  ignore_labels: ['ignore'], // list of lables being ignored from the changelog
  label_extractor: [], // extracts additional labels from the commit message given a regex
  duplicate_filter: undefined, // extract an identifier from a PR used to detect duplicates, will keep the last match (depends on `sort`)
  transformers: [], // transformers to apply on the PR description according to the `pr_template`
  tag_resolver: {
    // defines the logic on how to resolve the previous tag, only relevant if `fromTag` is not specified
    method: 'semver', // defines which method to use, by default it will use `semver` (dropping all non matching tags). Alternative `sort` is also available.
    filter: undefined, // filter out all tags not matching the regex
    transformer: undefined // transforms the tag name using the regex, run after the filter
  },
  base_branches: [], // target branches for the merged PR ignoring PRs with different target branch, by default it will get all PRs
  custom_placeholders: []
}