/** Source discovery and declaration validation shared by persistence documentation and schemas. */

import { globSync, readFileSync } from 'node:fs'
import { resolve, sep } from 'node:path'
import ts from 'typescript'
import { parseJsDoc, pointer, rawJsDoc, reportViolations } from './jsdoc.ts'

const root = resolve(import.meta.dirname, '..')

/** The package that owns the durable event vocabulary. */
const SESSION_PACKAGE = '@deepseek-ai/dsh-session'

/** The type-only module that plugin declaration merges augment. */
const SESSION_TYPES_MODULE = '@deepseek-ai/dsh-session/types'

/** Event-envelope declarations rendered before the per-event vocabulary. */
const EVENT_ENVELOPE_TYPE_NAMES = [
  'SessionEventType',
  'SurfaceEventType',
  'SurfaceOp',
  'SessionEvent',
] as const

type EventEnvelopeTypeName = typeof EVENT_ENVELOPE_TYPE_NAMES[number]

/** One log event, extracted from a `SessionEventMap` declaration. */
export interface LogEventEntry {
  /** Scoped name, e.g. `turn/start`. */
  name: string
  /** The scope prefix, e.g. `turn` (everything before the first `/`). */
  scope: string
  /** Payload type text (the member's type annotation, whitespace-collapsed). */
  payload: string
  /** Source member declaration and complete JSDoc, dedented from its container. */
  declaration: string
  /** Description prose (the member's JSDoc), one line per paragraph. */
  doc: string
  /** Source pointer `packages/…/file.ts:line` of the declaration. */
  source: string
}

/** A {@link LogEventEntry} plus its surface-eligibility badge. */
export interface AnnotatedLogEventEntry extends LogEventEntry {
  /** Whether the type is a `SurfaceEventType` member (may carry `surfaceOp`). */
  surface: boolean
}

/** One owning event-envelope declaration pasted into the generated catalog. */
export interface EventEnvelopeTypeEntry {
  /** Exported declaration name. */
  name: EventEnvelopeTypeName
  /** Verbatim type declaration, including its complete leading JSDoc. */
  declaration: string
  /** Source pointer `packages/…/file.ts:line` of the declaration. */
  source: string
}

const printer = ts.createPrinter({ removeComments: true })

/**
 * Render a member type on one line through the TypeScript printer, which adds
 * semicolon separators. Drop its trailing semicolon before `}` to match the
 * repository's inline-literal style.
 */
function payloadText(type: ts.TypeNode, sf: ts.SourceFile): string {
  return printer.printNode(ts.EmitHint.Unspecified, type, sf)
    .replace(/\s+/g, ' ')
    .replace(/;\s*\}/g, ' }')
    .trim()
}

/**
 * Copy a declaration from its leading JSDoc through its closing token while
 * removing only the indentation imposed by its containing interface/module.
 */
function declarationText(text: string, sf: ts.SourceFile, node: ts.Node): string {
  const raw = rawJsDoc(text, node)
  const nodeStart = node.getStart(sf)
  const start = raw ? text.lastIndexOf(raw, nodeStart) : nodeStart
  const { line } = sf.getLineAndCharacterOfPosition(start)
  const lineStart = sf.getPositionOfLineAndCharacter(line, 0)
  const indent = text.slice(lineStart, start)
  return text.slice(lineStart, node.end)
    .split('\n')
    .map(lineText => lineText.startsWith(indent) ? lineText.slice(indent.length) : lineText)
    .join('\n')
    .trimEnd()
}

/**
 * Every `interface SessionEventMap` declaration in a source file: the owning
 * top-level declaration (in `@deepseek-ai/dsh-session`) and any declaration
 * merge inside a `declare module '@deepseek-ai/dsh-session/types'` block. Both forms
 * declare members of the SAME merged interface, so both are catalogued
 * uniformly. `topLevel` distinguishes the owning form so the caller can verify
 * it actually lives in the owning package — an unrelated local interface that
 * happens to share the name must not be catalogued as the on-disk vocabulary.
 */
function sessionEventMapDecls(sf: ts.SourceFile): { decl: ts.InterfaceDeclaration; topLevel: boolean }[] {
  const decls: { decl: ts.InterfaceDeclaration; topLevel: boolean }[] = []
  for (const stmt of sf.statements) {
    if (ts.isInterfaceDeclaration(stmt) && stmt.name.text === 'SessionEventMap') decls.push({ decl: stmt, topLevel: true })
    if (ts.isModuleDeclaration(stmt) && ts.isStringLiteral(stmt.name) && stmt.name.text === SESSION_TYPES_MODULE
      && stmt.body && ts.isModuleBlock(stmt.body)) {
      for (const inner of stmt.body.statements) {
        if (ts.isInterfaceDeclaration(inner) && inner.name.text === 'SessionEventMap') decls.push({ decl: inner, topLevel: false })
      }
    }
  }
  return decls
}

/**
 * The npm package name owning a `packages/<group>/<pkg>/…` source file, read
 * from that package's manifest — or null when the manifest is missing or
 * unparseable (the caller treats null as "ownership unverifiable").
 */
function packageNameFor(rel: string, scanRoot: string): string | null {
  const dir = rel.split('/').slice(0, 3).join('/')
  try {
    const manifest = JSON.parse(readFileSync(resolve(scanRoot, dir, 'package.json'), 'utf8')) as { name?: string }
    return typeof manifest.name === 'string' ? manifest.name : null
  } catch {
    // Missing or malformed package.json — every real workspace package has one,
    // so this only arises in stripped-down fixture trees; either way ownership
    // cannot be verified and the caller reports the declaration.
    return null
  }
}

/**
 * Collect every `SessionEventMap` merge, rejecting inherited, non-literal,
 * untyped, undocumented, duplicate, or incorrectly owned members in one report.
 */
export function collectLogEvents(scanRoot: string = root): LogEventEntry[] {
  const entries: LogEventEntry[] = []
  const violations: string[] = []
  const seen = new Map<string, string>()
  let owningDecl: string | null = null
  for (const rel of globSync('packages/*/*/src/**/*.{ts,tsx}', { cwd: scanRoot }).map(s => s.split(sep).join('/')).sort()) {
    const abs = resolve(scanRoot, rel)
    const text = readFileSync(abs, 'utf8')
    if (!text.includes('SessionEventMap')) continue
    const sf = ts.createSourceFile(abs, text, ts.ScriptTarget.Latest, true)
    for (const { decl, topLevel } of sessionEventMapDecls(sf)) {
      const declSrc = pointer(rel, sf, decl)
      if (topLevel) {
        // The top-level form has one home: the single exported declaration in
        // the owning package. Same-named interfaces elsewhere are different
        // types and must not enter the on-disk catalog.
        const pkg = packageNameFor(rel, scanRoot)
        if (pkg !== SESSION_PACKAGE) {
          violations.push(`top-level interface SessionEventMap (${declSrc}) is outside ${SESSION_PACKAGE} (package ${pkg ?? 'unknown'}). Rename the interface, or contribute events via declare module '${SESSION_TYPES_MODULE}'.`)
          continue
        }
        const exported = decl.modifiers?.some(m => m.kind === ts.SyntaxKind.ExportKeyword) ?? false
        if (!exported) {
          violations.push(`top-level interface SessionEventMap (${declSrc}) is not exported; the owning vocabulary is the single exported declaration — rename a local helper interface.`)
          continue
        }
        if (owningDecl) {
          violations.push(`top-level interface SessionEventMap (${declSrc}) is already declared at ${owningDecl}; the owning vocabulary has exactly one home.`)
          continue
        }
        owningDecl = declSrc
      }
      if (decl.heritageClauses?.length) {
        violations.push(`SessionEventMap declaration (${declSrc}) uses extends; inherited keys would join keyof SessionEventMap without a catalog row — declare event members directly.`)
      }
      for (const member of decl.members) {
        const src = pointer(rel, sf, member)
        if (!ts.isPropertySignature(member) || !member.type) {
          // A method-form or type-less member still joins `keyof SessionEventMap`,
          // so skipping it silently would be exactly the undocumented-event hole
          // this catalog exists to close.
          const label = (member as { name?: ts.Node }).name?.getText(sf) ?? member.getText(sf).replace(/\s+/g, ' ')
          violations.push(`SessionEventMap member ${label} (${src}) is not a property signature with an explicit payload type; declare every log event as 'scope/name': <payload>.`)
          continue
        }
        if (!ts.isStringLiteral(member.name)) {
          violations.push(`log event at ${src} has a non-literal name; the catalog needs string-literal event names.`)
          continue
        }
        const name = member.name.text
        const where = `log event '${name}' (${src})`
        const prior = seen.get(name)
        if (prior) {
          violations.push(`${where} is already declared at ${prior}; an event type has exactly one declaration.`)
          continue
        }
        seen.set(name, src)
        const payload = payloadText(member.type, sf)
        const { doc, hasMode } = parseJsDoc(rawJsDoc(text, member))
        if (hasMode) {
          violations.push(`${where} carries an @mode tag, but a log event has no dispatch mode (it is not a cordis bus event — it rides the 'session/event' emit). Remove the tag.`)
        }
        if (!doc) {
          violations.push(`${where} has no description prose. Say what the event records and what its payload means — the JSDoc becomes the catalog entry.`)
        }
        const declaration = declarationText(text, sf, member)
        entries.push({ name, scope: name.split('/')[0] ?? name, payload, declaration, doc, source: src })
      }
    }
  }
  reportViolations('gen-persistence-catalog', violations)
  return entries
}

/**
 * Collect the exported declarations that compose the persisted event envelope,
 * preserving their source JSDoc and declaration text.
 */
export function collectEventEnvelopeTypes(scanRoot: string = root): EventEnvelopeTypeEntry[] {
  const found = new Map<EventEnvelopeTypeName, EventEnvelopeTypeEntry>()
  const violations: string[] = []
  const wanted = new Set<string>(EVENT_ENVELOPE_TYPE_NAMES)
  for (const rel of globSync('packages/*/*/src/**/*.{ts,tsx}', { cwd: scanRoot }).map(s => s.split(sep).join('/')).sort()) {
    const abs = resolve(scanRoot, rel)
    const text = readFileSync(abs, 'utf8')
    if (!EVENT_ENVELOPE_TYPE_NAMES.some(name => text.includes(name))) continue
    if (packageNameFor(rel, scanRoot) !== SESSION_PACKAGE) continue
    const sf = ts.createSourceFile(abs, text, ts.ScriptTarget.Latest, true)
    for (const stmt of sf.statements) {
      if (!ts.isTypeAliasDeclaration(stmt) || !wanted.has(stmt.name.text)) continue
      const name = stmt.name.text as EventEnvelopeTypeName
      const src = pointer(rel, sf, stmt)
      const where = `event-envelope type '${name}' (${src})`
      const prior = found.get(name)
      if (prior) {
        violations.push(`${where} is already declared at ${prior.source}; the persisted envelope type has exactly one owner.`)
        continue
      }
      if (!(stmt.modifiers?.some(m => m.kind === ts.SyntaxKind.ExportKeyword) ?? false)) {
        violations.push(`${where} is not exported.`)
      }
      const { doc, hasMode } = parseJsDoc(rawJsDoc(text, stmt))
      if (hasMode) violations.push(`${where} carries an @mode tag, but a persisted type has no dispatch mode.`)
      if (!doc) violations.push(`${where} has no description prose. The full JSDoc is part of the generated catalog.`)
      found.set(name, { name, declaration: declarationText(text, sf, stmt), source: src })
    }
  }
  const missing = EVENT_ENVELOPE_TYPE_NAMES.filter(name => !found.has(name))
  if (missing.length > 0) {
    violations.push(`missing event-envelope declaration(s): ${missing.join(', ')}.`)
  }
  reportViolations('gen-persistence-catalog', violations)
  return EVENT_ENVELOPE_TYPE_NAMES.map((name) => {
    const entry = found.get(name)
    if (!entry) throw new Error(`gen-persistence-catalog: missing checked event-envelope declaration '${name}'.`)
    return entry
  })
}

/**
 * Parse the `SurfaceEventType` union — the surface-eligible subset of event
 * types — from source. Hard-errors when the alias is missing, declared more
 * than once, or contains a non-string-literal member: the badge derivation
 * relies on the union being a closed set of literal event names.
 * `scanRoot` defaults to the repo root; tests pass a fixture dir.
 */
export function collectSurfaceEventTypes(scanRoot: string = root): string[] {
  const found: { names: string[]; source: string }[] = []
  for (const rel of globSync('packages/*/*/src/**/*.{ts,tsx}', { cwd: scanRoot }).map(s => s.split(sep).join('/')).sort()) {
    const abs = resolve(scanRoot, rel)
    const text = readFileSync(abs, 'utf8')
    if (!text.includes('SurfaceEventType')) continue
    const sf = ts.createSourceFile(abs, text, ts.ScriptTarget.Latest, true)
    for (const stmt of sf.statements) {
      if (!ts.isTypeAliasDeclaration(stmt) || stmt.name.text !== 'SurfaceEventType') continue
      const src = pointer(rel, sf, stmt)
      const members = ts.isUnionTypeNode(stmt.type) ? [...stmt.type.types] : [stmt.type]
      const names: string[] = []
      for (const m of members) {
        if (ts.isLiteralTypeNode(m) && ts.isStringLiteral(m.literal)) names.push(m.literal.text)
        else throw new Error(`gen-persistence-catalog: SurfaceEventType (${src}) has a non-string-literal member; the badge derivation needs a closed literal union.`)
      }
      found.push({ names, source: src })
    }
  }
  const only = found[0]
  if (!only) throw new Error('gen-persistence-catalog: no SurfaceEventType union found under packages/*/*/src.')
  if (found.length > 1) throw new Error(`gen-persistence-catalog: SurfaceEventType is declared more than once (${found.map(f => f.source).join(', ')}); the surface subset has exactly one owner.`)
  return only.names
}

/**
 * Attach the surface/log-only badge to each event. Hard-errors when a
 * `SurfaceEventType` union member names no collected event — a stale union
 * member would otherwise silently badge nothing.
 */
export function annotateSurface(events: LogEventEntry[], surfaceTypes: string[]): AnnotatedLogEventEntry[] {
  const names = new Set(events.map(e => e.name))
  const stale = surfaceTypes.filter(t => !names.has(t))
  if (stale.length > 0) {
    throw new Error(`gen-persistence-catalog: SurfaceEventType member(s) ${stale.map(t => `'${t}'`).join(', ')} name no declared log event (stale union member?).`)
  }
  const surface = new Set(surfaceTypes)
  return events.map(e => ({ ...e, surface: surface.has(e.name) }))
}