/**
 * Codex Link ("Codex Bağlama") — the pure half.
 *
 * AITURK IDE ships a small local Python bridge that lets the OpenAI Codex
 * installed on this machine use the IDE's models and combos. Turning the
 * feature on means editing a file the IDE does not own (Codex's `config.toml`)
 * and registering a login item, so every text transformation lives here as a
 * dependency-free, byte-preserving function that can be proven without
 * Electron, a filesystem, or a registry. `codex-link.ts` owns the decisions and
 * the side effects.
 *
 * Invariants:
 *  - Only the line carrying OUR trailing comment is ever written or removed.
 *  - An `openai_base_url` that is not ours means someone else's bridge is in
 *    charge: report `foreign` and change nothing.
 *  - Everything else in the file — including its line endings and BOM — comes
 *    back byte for byte.
 */

export const CODEX_LINK_PORT = 8795
export const CODEX_LINK_ORIGIN = `http://127.0.0.1:${CODEX_LINK_PORT}`
export const CODEX_LINK_STATUS_URL = `${CODEX_LINK_ORIGIN}/aiturk/codex-baglama/status`
export const CODEX_LINK_STOP_URL = `${CODEX_LINK_ORIGIN}/aiturk/codex-baglama/stop`
export const CODEX_LINK_REFRESH_URL = `${CODEX_LINK_ORIGIN}/aiturk/codex-baglama/refresh`

/** The trailing comment that marks the line as ours. */
export const CODEX_LINK_MARKER = '# AITURK IDE Codex Baglama'
// Must equal SURUM in assets/codex-bridge/bridge.py; a running bridge that reports
// another version is restarted so an updated IDE never keeps an old bridge alive.
export const CODEX_BRIDGE_VERSION = '7'
export const CODEX_LINK_LINE = `openai_base_url = "${CODEX_LINK_ORIGIN}/backend-api/codex"  ${CODEX_LINK_MARKER}`

export const CODEX_LINK_RUN_KEY = 'HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run'
export const CODEX_LINK_RUN_VALUE = 'AITURK-IDE-Codex-Baglama'
export const CODEX_LINK_LAUNCHER_NAME = 'baslat.pyw'

// Windows documents Run-key command lines as "no longer than 260 characters".
// A longer value is not reliably started at sign-in, so the direct command is
// only used when it fits (see autostartPlan).
export const CODEX_LINK_RUN_COMMAND_MAX = 260

/** Who owns the top-level `openai_base_url` in a Codex config. */
export type CodexConfigOwner = 'absent' | 'foreign' | 'ours'

interface Line {
  eol: string
  text: string
}

const BOM = '\uFEFF'
const KEY_PATTERN = /^[ \t]*(?:openai_base_url|"openai_base_url"|'openai_base_url')[ \t]*=/

// Split into lines WITHOUT losing anything: joining `text + eol` of every entry
// reproduces the input exactly, whatever mix of \n, \r\n and \r it used.
function splitLines(source: string): Line[] {
  const lines: Line[] = []
  let start = 0

  while (start < source.length) {
    let end = start

    while (end < source.length && source[end] !== '\n' && source[end] !== '\r') {
      end += 1
    }

    let eol = ''

    if (end < source.length) {
      eol = source[end] === '\r' && source[end + 1] === '\n' ? '\r\n' : source[end]
    }

    lines.push({ eol, text: source.slice(start, end) })
    start = end + eol.length
  }

  return lines
}

function joinLines(lines: Line[]): string {
  return lines.map(line => line.text + line.eol).join('')
}

function splitBom(source: string): { body: string; bom: string } {
  return source.startsWith(BOM) ? { body: source.slice(1), bom: BOM } : { body: source, bom: '' }
}

type MultilineQuote = "'''" | '"""' | null

interface ValueState {
  depth: number
  multiline: MultilineQuote
}

// Index just past the `=` of a `key = value` line, or the line length when the
// line holds no value (blank, comment, malformed). Quoted keys may contain `=`.
function valueStart(text: string): number {
  let pos = 0

  while (pos < text.length) {
    const char = text[pos]

    if (char === '#') {
      return text.length
    }

    if (char === '=') {
      return pos + 1
    }

    if (char === '"' || char === "'") {
      pos += 1

      while (pos < text.length && text[pos] !== char) {
        pos += char === '"' && text[pos] === '\\' ? 2 : 1
      }
    }

    pos += 1
  }

  return text.length
}

// Walk a value just far enough to know whether the NEXT line is still inside it
// (multi-line string or array). That is the only TOML the top-level scan needs:
// without it, text inside a multi-line value could pass for a key or a table
// header.
function scanValue(text: string, from: number, state: ValueState): ValueState {
  let { depth, multiline } = state
  let pos = from

  while (pos < text.length) {
    if (multiline) {
      if (multiline === '"""' && text[pos] === '\\') {
        pos += 2

        continue
      }

      if (text.startsWith(multiline, pos)) {
        pos += 3

        // Up to two quotes may sit directly before the closing delimiter.
        while (text[pos] === multiline[0]) {
          pos += 1
        }

        multiline = null

        continue
      }

      pos += 1

      continue
    }

    const char = text[pos]

    if (char === '#') {
      break
    }

    if (text.startsWith('"""', pos) || text.startsWith("'''", pos)) {
      multiline = text.slice(pos, pos + 3) as MultilineQuote
      pos += 3

      continue
    }

    if (char === '"' || char === "'") {
      pos += 1

      while (pos < text.length && text[pos] !== char) {
        pos += char === '"' && text[pos] === '\\' ? 2 : 1
      }

      pos += 1

      continue
    }

    if (char === '[' || char === '{') {
      depth += 1
    } else if (char === ']' || char === '}') {
      depth = Math.max(0, depth - 1)
    }

    pos += 1
  }

  return { depth, multiline }
}

// Indices of the top-level `openai_base_url` lines: those before the first
// `[table]` header, outside comments and multi-line values.
function topLevelEntries(lines: Line[]): { index: number; ours: boolean }[] {
  const entries: { index: number; ours: boolean }[] = []
  let state: ValueState = { depth: 0, multiline: null }

  for (let index = 0; index < lines.length; index += 1) {
    const { text } = lines[index]
    let from = 0

    if (!state.multiline && state.depth === 0) {
      if (text.trimStart().startsWith('[')) {
        break
      }

      if (KEY_PATTERN.test(text)) {
        // Ours by marker or by value: Codex may rewrite its config and drop the comment.
        entries.push({
          index,
          ours: text.includes(CODEX_LINK_MARKER) || text.includes(`"${CODEX_LINK_ORIGIN}/backend-api/codex"`)
        })
      }

      from = valueStart(text)
    }

    state = scanValue(text, from, state)
  }

  return entries
}

function ownerOf(entries: { ours: boolean }[]): CodexConfigOwner {
  if (entries.some(entry => !entry.ours)) {
    return 'foreign'
  }

  return entries.length > 0 ? 'ours' : 'absent'
}

/** Who owns the top-level `openai_base_url` of this config text. */
export function inspectCodexConfig(source: string): CodexConfigOwner {
  return ownerOf(topLevelEntries(splitLines(splitBom(source).body)))
}

export interface CodexConfigEdit {
  changed: boolean
  owner: CodexConfigOwner
  text: string
}

/**
 * Point Codex at the bridge. Idempotent; a foreign `openai_base_url` leaves the
 * text untouched and reports `foreign`.
 *
 * The line goes on the very first line: top-level keys must precede the first
 * table header, and the top of the file is the one position that is always
 * top-level without having to understand the values below it.
 */
export function addCodexLinkLine(source: string): CodexConfigEdit {
  const { body, bom } = splitBom(source)
  const lines = splitLines(body)
  const entries = topLevelEntries(lines)
  const owner = ownerOf(entries)

  if (owner === 'foreign') {
    return { changed: false, owner, text: source }
  }

  if (owner === 'ours') {
    const [first, ...duplicates] = entries

    if (duplicates.length === 0 && lines[first.index].text === CODEX_LINK_LINE) {
      return { changed: false, owner, text: source }
    }

    // A stale copy of our line (older address) or an accidental duplicate:
    // normalize to exactly one current line, in place.
    const drop = new Set(duplicates.map(entry => entry.index))
    lines[first.index] = { ...lines[first.index], text: CODEX_LINK_LINE }

    return { changed: true, owner, text: bom + joinLines(lines.filter((_line, index) => !drop.has(index))) }
  }

  const eol = body.includes('\r\n') ? '\r\n' : '\n'

  return { changed: true, owner: 'ours', text: `${bom}${CODEX_LINK_LINE}${eol}${body}` }
}

/** Remove our line (and only ours). A foreign key is left exactly as it was. */
export function removeCodexLinkLine(source: string): CodexConfigEdit {
  const { body, bom } = splitBom(source)
  const lines = splitLines(body)
  const entries = topLevelEntries(lines)
  const drop = new Set(entries.filter(entry => entry.ours).map(entry => entry.index))
  const remaining = ownerOf(entries.filter(entry => !entry.ours))

  if (drop.size === 0) {
    return { changed: false, owner: remaining, text: source }
  }

  return { changed: true, owner: remaining, text: bom + joinLines(lines.filter((_line, index) => !drop.has(index))) }
}

// ── Preference file ─────────────────────────────────────────────────────────

export interface CodexLinkSettings {
  enabled: boolean
  /** Every field of the stored object, so a rewrite keeps what it did not set. */
  stored: Record<string, unknown>
}

/** Missing, unreadable or malformed means ON: the feature is on by default. */
export function parseCodexLinkSettings(raw: null | string | undefined): CodexLinkSettings {
  if (typeof raw !== 'string') {
    return { enabled: true, stored: {} }
  }

  try {
    const parsed = JSON.parse(raw)

    if (!parsed || typeof parsed !== 'object' || Array.isArray(parsed)) {
      return { enabled: true, stored: {} }
    }

    return { enabled: parsed.enabled !== false, stored: parsed as Record<string, unknown> }
  } catch {
    return { enabled: true, stored: {} }
  }
}

export function serializeCodexLinkSettings(stored: Record<string, unknown>, enabled: boolean): string {
  const kapsam = typeof stored.kapsam === 'string' && stored.kapsam ? stored.kapsam : 'ide'

  return `${JSON.stringify({ ...stored, enabled, kapsam }, null, 2)}\n`
}

// ── Bridge configuration ────────────────────────────────────────────────────

/** `bridge.json`, rewritten on every apply. */
export function codexBridgeConfig() {
  return {
    port: CODEX_LINK_PORT,
    chatgpt_backend: 'https://chatgpt.com',
    routes: {},
    nine_router_catalog: { enabled: false },
    pano_kanca_user: false,
    ozet_kopru: { enabled: true, kapsam: 'hepsi', openai_modeli: 'gpt-6-luna', dongu_siniri: 8, dongu_art_arda: 3 }
  }
}

export function serializeCodexBridgeConfig(): string {
  return `${JSON.stringify(codexBridgeConfig(), null, 2)}\n`
}

// ── Bridge command line ─────────────────────────────────────────────────────

export interface CodexBridgeLaunch {
  bridgeHome: string
  bridgeScript: string
  hermesHome: string
}

/** Arguments after the interpreter — identical for the spawn and the login item. */
export function codexBridgeArgs({ bridgeHome, bridgeScript, hermesHome }: CodexBridgeLaunch): string[] {
  return [bridgeScript, '--home', bridgeHome, '--hermes-home', hermesHome]
}

// A trailing backslash would escape the closing quote (`"C:\dir\"`).
function quoted(value: string): string {
  return `"${value.replace(/[\\/]+$/, '')}"`
}

/** `"<pythonw>" "<bridge.py>" --home "<data>" --hermes-home "<agent>"` */
export function codexBridgeCommandLine(python: string, launch: CodexBridgeLaunch): string {
  const [script, homeFlag, home, hermesFlag, hermes] = codexBridgeArgs(launch)

  return `${quoted(python)} ${quoted(script)} ${homeFlag} ${quoted(home)} ${hermesFlag} ${quoted(hermes)}`
}

/**
 * A tiny windowless launcher for the login item, used when the direct command
 * would not fit a Run value. It runs the bridge exactly as the direct command
 * would: same script, same arguments, the script's folder first on sys.path so
 * its helper modules import.
 */
export function codexBridgeLauncherSource(launch: CodexBridgeLaunch): string {
  const argv = JSON.stringify(codexBridgeArgs(launch))

  return [
    '# Written by AITURK IDE (Settings > Codex Baglama). Regenerated on every sync; do not edit.',
    'import os',
    'import runpy',
    'import sys',
    '',
    `ARGV = ${argv}`,
    '',
    'sys.argv = list(ARGV)',
    'sys.path.insert(0, os.path.dirname(ARGV[0]))',
    "runpy.run_path(ARGV[0], run_name='__main__')",
    ''
  ].join('\n')
}

export interface CodexAutostartPlan {
  command: string
  /** Launcher file to write first; null when the direct command is used. */
  launcher: { path: string; source: string } | null
}

/**
 * The login-item command. Prefer the direct bridge command; fall back to the
 * launcher when that exceeds the Run-value limit. Returns null when not even
 * the launcher form fits (nothing is registered rather than something that
 * silently never starts).
 */
export function codexAutostartPlan(
  python: string,
  launch: CodexBridgeLaunch,
  launcherPath: string
): CodexAutostartPlan | null {
  const direct = codexBridgeCommandLine(python, launch)

  if (direct.length <= CODEX_LINK_RUN_COMMAND_MAX) {
    return { command: direct, launcher: null }
  }

  const viaLauncher = `${quoted(python)} ${quoted(launcherPath)}`

  if (viaLauncher.length > CODEX_LINK_RUN_COMMAND_MAX) {
    return null
  }

  return { command: viaLauncher, launcher: { path: launcherPath, source: codexBridgeLauncherSource(launch) } }
}