import { existsSync, readFileSync } from "node:fs"
import { homedir } from "node:os"
import { join } from "node:path"
import type { CheckResult, CheckDefinition, PluginInfo } from "../types"
import { CHECK_IDS, CHECK_NAMES, PACKAGE_NAME } from "../constants"
import { parseJsonc } from "../../../shared"

const OPENCODE_CONFIG_DIR = join(homedir(), ".config", "opencode")
const OPENCODE_JSON = join(OPENCODE_CONFIG_DIR, "opencode.json")
const OPENCODE_JSONC = join(OPENCODE_CONFIG_DIR, "opencode.jsonc")

function detectConfigPath(): { path: string; format: "json" | "jsonc" } | null {
  if (existsSync(OPENCODE_JSONC)) {
    return { path: OPENCODE_JSONC, format: "jsonc" }
  }
  if (existsSync(OPENCODE_JSON)) {
    return { path: OPENCODE_JSON, format: "json" }
  }
  return null
}

function findPluginEntry(plugins: string[]): { entry: string; isPinned: boolean; version: string | null } | null {
  for (const plugin of plugins) {
    if (plugin === PACKAGE_NAME || plugin.startsWith(`${PACKAGE_NAME}@`)) {
      const isPinned = plugin.includes("@")
      const version = isPinned ? plugin.split("@")[1] : null
      return { entry: plugin, isPinned, version }
    }
  }
  return null
}

export function getPluginInfo(): PluginInfo {
  const configInfo = detectConfigPath()

  if (!configInfo) {
    return {
      registered: false,
      configPath: null,
      entry: null,
      isPinned: false,
      pinnedVersion: null,
    }
  }

  try {
    const content = readFileSync(configInfo.path, "utf-8")
    const config = parseJsonc<{ plugin?: string[] }>(content)
    const plugins = config.plugin ?? []
    const pluginEntry = findPluginEntry(plugins)

    if (!pluginEntry) {
      return {
        registered: false,
        configPath: configInfo.path,
        entry: null,
        isPinned: false,
        pinnedVersion: null,
      }
    }

    return {
      registered: true,
      configPath: configInfo.path,
      entry: pluginEntry.entry,
      isPinned: pluginEntry.isPinned,
      pinnedVersion: pluginEntry.version,
    }
  } catch {
    return {
      registered: false,
      configPath: configInfo.path,
      entry: null,
      isPinned: false,
      pinnedVersion: null,
    }
  }
}

export async function checkPluginRegistration(): Promise<CheckResult> {
  const info = getPluginInfo()

  if (!info.configPath) {
    return {
      name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
      status: "fail",
      message: "OpenCode config file not found",
      details: [
        "Run: bunx oh-my-opencode install",
        `Expected: ${OPENCODE_JSON} or ${OPENCODE_JSONC}`,
      ],
    }
  }

  if (!info.registered) {
    return {
      name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
      status: "fail",
      message: "Plugin not registered in config",
      details: [
        "Run: bunx oh-my-opencode install",
        `Config: ${info.configPath}`,
      ],
    }
  }

  const message = info.isPinned
    ? `Registered (pinned: ${info.pinnedVersion})`
    : "Registered"

  return {
    name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
    status: "pass",
    message,
    details: [`Config: ${info.configPath}`],
  }
}

export function getPluginCheckDefinition(): CheckDefinition {
  return {
    id: CHECK_IDS.PLUGIN_REGISTRATION,
    name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
    category: "installation",
    check: checkPluginRegistration,
    critical: true,
  }
}