import { basename, resolve } from 'node:path'

import { CONFIG_FILE } from './constants.js'
import { finalizeAddOns } from './add-ons.js'
import { getFrameworkById } from './frameworks.js'
import { createMemoryEnvironment } from './environment.js'
import { createApp } from './create-app.js'
import {
  readConfigFileFromEnvironment,
  writeConfigFileToEnvironment,
} from './config-file.js'
import { formatCommand } from './utils.js'
import { packageManagerInstall } from './package-manager.js'
import {
  isBase64,
  recursivelyGatherFilesFromEnvironment,
} from './file-helpers.js'
import { mergePackageJSON } from './package-json.js'
import { runSpecialSteps } from './special-steps/index.js'
import { loadStarter } from './custom-add-ons/starter.js'
import { setupIntent } from './integrations/intent.js'

import type { Environment, Options } from './types.js'
import type { PersistedOptions } from './config-file.js'

const ENV_FILE_NAMES = new Set(['.env', '.env.local', '.env.example'])
const ENV_VARIABLE_PATTERN = /^\s*(?:export\s+)?([A-Za-z_][A-Za-z0-9_]*)\s*=/

function mergeEnvFileContents(existing: string, generated: string) {
  const declaredVariables = new Set<string>()
  for (const line of existing.split(/\r?\n/)) {
    const match = line.match(ENV_VARIABLE_PATTERN)
    if (match) {
      declaredVariables.add(match[1])
    }
  }

  const additions: Array<string> = []
  for (const block of generated.split(/\r?\n(?:[ \t]*\r?\n)+/)) {
    const blockLines = block.split(/\r?\n/)
    while (blockLines.at(-1) === '') {
      blockLines.pop()
    }
    const lines: Array<string> = []
    let addedVariableCount = 0
    for (const line of blockLines) {
      const match = line.match(ENV_VARIABLE_PATTERN)
      if (!match) {
        lines.push(line)
        continue
      }
      if (declaredVariables.has(match[1])) {
        continue
      }

      declaredVariables.add(match[1])
      addedVariableCount++
      lines.push(line)
    }

    if (addedVariableCount > 0) {
      additions.push(lines.join('\n'))
    }
  }

  if (additions.length === 0) {
    return existing
  }

  const separator = existing.length
    ? existing.endsWith('\n\n')
      ? ''
      : existing.endsWith('\n')
        ? '\n'
        : '\n\n'
    : ''
  const trailingNewline = generated.endsWith('\n') ? '\n' : ''
  return `${existing}${separator}${additions.join('\n\n')}${trailingNewline}`
}

export async function hasPendingGitChanges(
  environment: Environment,
  cwd: string,
) {
  const { stdout } = await environment.execute(
    'git',
    ['status', '--porcelain'],
    cwd,
  )
  return stdout.length > 0
}

async function createOptions(
  json: PersistedOptions,
  addOns: Array<string>,
  targetDir: string,
): Promise<Options> {
  const framework = getFrameworkById(json.framework)

  const starter = json.starter ? await loadStarter(json.starter) : undefined
  const chosenAddOns = await finalizeAddOns(framework!, json.mode!, [
    ...json.chosenAddOns,
    ...addOns,
  ])

  return {
    ...json,
    framework,
    tailwind:
      (json.tailwind ?? true) ||
      chosenAddOns.some((addOn) => addOn.tailwind === true),
    addOns: true,
    chosenAddOns,
    targetDir,
    starter,
    intent: json.intent ?? false,
  } as Options
}

async function runCreateApp(options: Required<Options>) {
  const { environment, output } = createMemoryEnvironment(options.targetDir)
  await createApp(environment, options)
  return output
}

export async function getCurrentConfiguration(
  environment: Environment,
  cwd: string,
) {
  const persistedOptions = await readConfigFileFromEnvironment(environment, cwd)
  if (!persistedOptions) {
    environment.error(
      'There is no .cta.json file in your project.',
      'This is probably because this was created with an older version of create-tsrouter-app.',
    )
    return undefined
  }

  return persistedOptions
}

export async function writeFiles(
  environment: Environment,
  cwd: string,
  output: {
    files: Record<string, string>
    deletedFiles: Array<string>
  },
  forced: boolean,
) {
  const toRelativePath = (filePath: string) => {
    const normalizedFilePath = filePath.replace(/\\/g, '/')
    const normalizedCwd = cwd.replace(/\\/g, '/')
    const cwdWithoutDrive = normalizedCwd.replace(/^[a-zA-Z]:/, '')
    const cwdWithoutDriveNoLeading = cwdWithoutDrive.replace(/^\/+/, '')

    if (normalizedFilePath === normalizedCwd) {
      return ''
    }
    if (normalizedFilePath.startsWith(`${normalizedCwd}/`)) {
      return normalizedFilePath.slice(normalizedCwd.length + 1)
    }
    if (normalizedFilePath === cwdWithoutDrive) {
      return ''
    }
    if (normalizedFilePath.startsWith(`${cwdWithoutDrive}/`)) {
      return normalizedFilePath.slice(cwdWithoutDrive.length + 1)
    }
    if (normalizedFilePath === cwdWithoutDriveNoLeading) {
      return ''
    }
    if (normalizedFilePath.startsWith(`${cwdWithoutDriveNoLeading}/`)) {
      return normalizedFilePath.slice(cwdWithoutDriveNoLeading.length + 1)
    }

    return normalizedFilePath.replace(/^\/+/, '')
  }

  const relativeOutputFiles = Object.keys(output.files).reduce<
    Record<string, string>
  >((acc, filePath) => {
    acc[toRelativePath(filePath)] = output.files[filePath]
    return acc
  }, {})

  const currentFiles = await recursivelyGatherFilesFromEnvironment(
    environment,
    cwd,
    false,
  )

  for (const [relativeFile, generatedContents] of Object.entries(
    relativeOutputFiles,
  )) {
    if (
      ENV_FILE_NAMES.has(basename(relativeFile)) &&
      relativeFile in currentFiles
    ) {
      relativeOutputFiles[relativeFile] = mergeEnvFileContents(
        currentFiles[relativeFile],
        generatedContents,
      )
    }
  }

  const overwrittenFiles: Array<string> = []
  const changedFiles: Array<string> = []
  for (const relativeFile of Object.keys(relativeOutputFiles)) {
    if (currentFiles[relativeFile]) {
      if (currentFiles[relativeFile] !== relativeOutputFiles[relativeFile]) {
        overwrittenFiles.push(relativeFile)
      }
    } else {
      changedFiles.push(relativeFile)
    }
  }

  const deletedFiles = output.deletedFiles
    .map(toRelativePath)
    .filter((file) => environment.exists(resolve(cwd, file)))

  if (!forced && (overwrittenFiles.length || deletedFiles.length)) {
    environment.warn(
      'The following files will be changed or deleted',
      [...overwrittenFiles, ...deletedFiles].join('\n'),
    )
    const shouldContinue = await environment.confirm('Do you want to continue?')
    if (!shouldContinue) {
      throw new Error('User cancelled')
    }
  }

  for (const relativeFilePath of deletedFiles) {
    await environment.deleteFile(resolve(cwd, relativeFilePath))
  }

  environment.startStep({
    id: 'write-files',
    type: 'file',
    message: 'Writing add-on files...',
  })

  for (const file of [...changedFiles, ...overwrittenFiles]) {
    const fName = basename(file)
    const contents = relativeOutputFiles[file]
    if (fName === 'package.json') {
      const currentJson = JSON.parse(
        await environment.readFile(resolve(cwd, file)),
      )
      const newJSON = mergePackageJSON(currentJson, JSON.parse(contents))
      environment.writeFile(
        resolve(cwd, file),
        JSON.stringify(newJSON, null, 2),
      )
    } else if (fName !== CONFIG_FILE) {
      if (isBase64(contents)) {
        await environment.writeFileBase64(resolve(cwd, file), contents)
      } else {
        await environment.writeFile(resolve(cwd, file), contents)
      }
    }
  }

  environment.finishStep('write-files', 'Add-on files written')
}

export async function runNewCommands(
  environment: Environment,
  originalOptions: PersistedOptions,
  cwd: string,
  output: {
    commands: Array<{
      command: string
      args: Array<string>
    }>
  },
) {
  const originalOutput = await runCreateApp({
    ...(await createOptions(originalOptions, [], cwd)),
  } as Required<Options>)

  const originalCommands = new Set(
    originalOutput.commands.map((c) => [c.command, ...c.args].join(' ')),
  )

  for (const command of output.commands) {
    const commandString = [command.command, ...command.args].join(' ')
    if (!originalCommands.has(commandString)) {
      environment.startStep({
        id: 'run-commands',
        type: 'command',
        message: `Running ${formatCommand({ command: command.command, args: command.args })}...`,
      })
      await environment.execute(command.command, command.args, cwd, {
        inherit: true,
      })
      environment.finishStep('run-commands', 'Setup commands complete')
    }
  }
}

export async function addToApp(
  environment: Environment,
  addOns: Array<string>,
  cwd: string,
  options?: {
    forced?: boolean
    intent?: boolean
  },
) {
  const persistedOptions = await getCurrentConfiguration(environment, cwd)
  if (!persistedOptions) {
    return
  }

  if (!options?.forced && (await hasPendingGitChanges(environment, cwd))) {
    environment.error(
      'You have pending git changes.',
      'Please commit or stash them before adding add-ons.',
    )
    return
  }

  environment.intro(`Adding ${addOns.join(', ')} to the project...`)
  environment.startStep({
    id: 'processing-new-app-setup',
    type: 'file',
    message: 'Processing new app setup...',
  })

  const newOptions = await createOptions(persistedOptions, addOns, cwd)

  const output = await runCreateApp({
    ...newOptions,
    targetDir: cwd,
  } as Required<Options>)

  await writeFiles(environment, cwd, output, !!options?.forced)

  environment.finishStep(
    'processing-new-app-setup',
    'Application files written',
  )

  // Run any special steps for the new add-ons

  const specialSteps = new Set<string>([])
  for (const addOn of newOptions.chosenAddOns) {
    for (const step of addOn.addOnSpecialSteps || []) {
      if (addOns.includes(addOn.id)) {
        specialSteps.add(step)
      }
    }
  }
  if (specialSteps.size) {
    await runSpecialSteps(environment, newOptions, Array.from(specialSteps))
  }

  // Install dependencies

  environment.startStep({
    id: 'install-dependencies',
    type: 'package-manager',
    message: `Installing dependencies via ${newOptions.packageManager}...`,
  })
  const s = environment.spinner()
  s.start(`Installing dependencies via ${newOptions.packageManager}...`)
  await packageManagerInstall(
    environment,
    newOptions.targetDir,
    newOptions.packageManager,
  )
  s.stop(`Installed dependencies`)
  environment.finishStep('install-dependencies', 'Dependencies installed')

  // Run any post-init special steps for the new add-ons
  const postInitSpecialSteps = new Set<string>([])
  for (const addOn of newOptions.chosenAddOns) {
    for (const step of addOn.postInitSpecialSteps || []) {
      if (addOns.includes(addOn.id)) {
        postInitSpecialSteps.add(step)
      }
    }
  }
  if (postInitSpecialSteps.size) {
    await runSpecialSteps(
      environment,
      newOptions,
      Array.from(postInitSpecialSteps),
    )
  }

  // Handle new commands

  await runNewCommands(environment, persistedOptions, cwd, output)

  const intent = options?.intent ?? persistedOptions.intent ?? true
  newOptions.intent = intent
  await setupIntent(environment, cwd, newOptions)

  environment.startStep({
    id: 'write-config-file',
    type: 'file',
    message: 'Writing config file...',
  })
  writeConfigFileToEnvironment(environment, newOptions)
  environment.finishStep('write-config-file', 'Config file written')

  environment.outro(`Add-ons ${addOns.join(', ')} added!`)
}