import { Prisma } from '@/generated/prisma/client'

const VALID_KEY = /^[a-z][a-z0-9_]{0,63}$/

export const RANK_GENERAL_FIELDS = new Set([
  'rank_name',
  'hidden_rank',
  'badge',
  'job_description',
  'staff_color',
  'staff_background',
  'level',
  'room_effect',
  'log_commands',
  'prefix',
  'prefix_color',
  'auto_credits_amount',
  'auto_pixels_amount',
  'auto_gotw_amount',
  'auto_points_amount',
])

export interface EmulatorRankSummary {
  id: number
  rank_name: string
  badge: string
  level: number
  prefix: string
  prefix_color: string
  hidden_rank: string
}

export interface EmulatorRankForEdit extends EmulatorRankSummary {
  log_commands: string
  room_effect: number
  auto_credits_amount: number
  auto_pixels_amount: number
  auto_gotw_amount: number
  auto_points_amount: number
  permissions: Record<string, string>
  permissionMaxValues: Record<string, number>
}

type RawDb = {
  $queryRaw: <T = unknown>(query: Prisma.Sql) => Promise<T>
  $executeRaw: (query: Prisma.Sql) => Promise<number>
  $transaction: <T>(queries: Promise<T>[]) => Promise<T[]>
}

export function getRankPermissionColumn(rankId: number) {
  if (!Number.isInteger(rankId) || rankId <= 0 || rankId > 255) {
    throw new Error('Invalid rank id')
  }
  return `rank_${rankId}`
}

export function toPermissionValue(value: string | number) {
  const parsed = typeof value === 'number' ? value : Number.parseInt(value, 10)
  if (!Number.isFinite(parsed) || parsed < 0) return 0
  return Math.min(Math.trunc(parsed), 255)
}

export function splitRankUpdateFields(fields: Record<string, string | number>) {
  const rankFields: Record<string, string | number> = {}
  const permissionFields: Record<string, number> = {}

  for (const [key, value] of Object.entries(fields)) {
    if (key === 'id' || !VALID_KEY.test(key)) continue
    if (RANK_GENERAL_FIELDS.has(key)) {
      rankFields[key] = value
    } else {
      permissionFields[key] = toPermissionValue(value)
    }
  }

  return { rankFields, permissionFields }
}

export async function fetchEmulatorRankSummaries(db: RawDb): Promise<EmulatorRankSummary[]> {
  const rows = await db.$queryRaw<Record<string, unknown>[]>(
    Prisma.sql`
      SELECT id, rank_name, badge, level, prefix, prefix_color, hidden_rank
      FROM permission_ranks
      ORDER BY id ASC
    `,
  )

  return rows.map((row) => ({
    id: Number(row.id),
    rank_name: String(row.rank_name ?? ''),
    badge: String(row.badge ?? ''),
    level: Number(row.level ?? 1),
    prefix: String(row.prefix ?? ''),
    prefix_color: String(row.prefix_color ?? ''),
    hidden_rank: String(row.hidden_rank ?? '0'),
  }))
}

export async function fetchEmulatorRankForEdit(
  db: RawDb,
  rankId: number,
): Promise<EmulatorRankForEdit | null> {
  const rankRows = await db.$queryRaw<Record<string, unknown>[]>(
    Prisma.sql`
      SELECT id, rank_name, badge, level, prefix, prefix_color, hidden_rank,
             log_commands, room_effect, auto_credits_amount, auto_pixels_amount,
             auto_gotw_amount, auto_points_amount
      FROM permission_ranks
      WHERE id = ${rankId}
    `,
  )
  if (rankRows.length === 0) return null

  const rankColumn = getRankPermissionColumn(rankId)
  const permissionRows = await db.$queryRaw<
    { permission_key: string; max_value: number; value: number | string | null }[]
  >(
    Prisma.sql`
      SELECT permission_key, max_value, ${Prisma.raw(quoteIdentifier(rankColumn))} AS value
      FROM permission_definitions
      ORDER BY permission_key ASC
    `,
  )

  const permissions: Record<string, string> = {}
  const permissionMaxValues: Record<string, number> = {}
  for (const row of permissionRows) {
    permissions[row.permission_key] = String(row.value ?? 0)
    permissionMaxValues[row.permission_key] = Number(row.max_value ?? 1)
  }

  const row = rankRows[0]
  return {
    id: Number(row.id),
    rank_name: String(row.rank_name ?? ''),
    badge: String(row.badge ?? ''),
    level: Number(row.level ?? 1),
    prefix: String(row.prefix ?? ''),
    prefix_color: String(row.prefix_color ?? ''),
    hidden_rank: String(row.hidden_rank ?? '0'),
    log_commands: String(row.log_commands ?? '0'),
    room_effect: Number(row.room_effect ?? 0),
    auto_credits_amount: Number(row.auto_credits_amount ?? 0),
    auto_pixels_amount: Number(row.auto_pixels_amount ?? 0),
    auto_gotw_amount: Number(row.auto_gotw_amount ?? 0),
    auto_points_amount: Number(row.auto_points_amount ?? 0),
    permissions,
    permissionMaxValues,
  }
}

export async function createEmulatorRank(
  db: RawDb,
  data: { rank_name: string; level: number },
): Promise<number> {
  const rows = await db.$queryRaw<{ next_id: number }[]>(
    Prisma.sql`SELECT COALESCE(MAX(id), 0) + 1 AS next_id FROM permission_ranks`,
  )
  const id = Number(rows[0]?.next_id ?? 1)
  await ensurePermissionRankColumn(db, id)
  await resetPermissionRankColumn(db, id)

  await db.$transaction([
    db.$executeRaw(
      Prisma.sql`
        INSERT INTO permission_ranks (id, rank_name, level)
        VALUES (${id}, ${data.rank_name}, ${data.level})
      `,
    ),
    db.$executeRaw(
      Prisma.sql`
        INSERT INTO permissions (id, rank_name, level)
        VALUES (${id}, ${data.rank_name}, ${data.level})
        ON DUPLICATE KEY UPDATE rank_name = VALUES(rank_name), level = VALUES(level)
      `,
    ),
  ])

  return id
}

export async function deleteEmulatorRank(db: RawDb, rankId: number) {
  await resetPermissionRankColumn(db, rankId)
  await db.$transaction([
    db.$executeRaw(Prisma.sql`DELETE FROM permission_ranks WHERE id = ${rankId}`),
    db.$executeRaw(Prisma.sql`DELETE FROM permissions WHERE id = ${rankId}`),
  ])
}

export async function updateEmulatorRank(
  db: RawDb,
  rankId: number,
  fields: Record<string, string | number>,
) {
  const { rankFields, permissionFields } = splitRankUpdateFields(fields)

  if (Object.keys(rankFields).length > 0) {
    await updateTableFields(db, 'permission_ranks', rankId, rankFields)
    await updateLegacyPermissionFields(db, rankId, rankFields)
  }

  if (Object.keys(permissionFields).length > 0) {
    await updatePermissionDefinitionValues(db, rankId, permissionFields)
    await updateLegacyPermissionFields(db, rankId, permissionFields)
  }
}

async function updateTableFields(
  db: RawDb,
  table: string,
  rankId: number,
  fields: Record<string, string | number>,
) {
  const assignments = Object.entries(fields).map(
    ([key, value]) => Prisma.sql`${Prisma.raw(quoteIdentifier(key))} = ${value}`,
  )
  return db.$executeRaw(
    Prisma.sql`
      UPDATE ${Prisma.raw(quoteIdentifier(table))}
      SET ${Prisma.join(assignments, ', ')}
      WHERE id = ${rankId}
    `,
  )
}

async function updatePermissionDefinitionValues(
  db: RawDb,
  rankId: number,
  permissionFields: Record<string, number>,
) {
  const rankColumn = getRankPermissionColumn(rankId)
  const entries = Object.entries(permissionFields)
  const cases = entries.map(
    ([key, value]) => Prisma.sql`WHEN ${key} THEN LEAST(${value}, max_value)`,
  )
  const keys = entries.map(([key]) => key)

  return db.$executeRaw(
    Prisma.sql`
      UPDATE permission_definitions
      SET ${Prisma.raw(quoteIdentifier(rankColumn))} =
        CASE permission_key
          ${Prisma.join(cases, ' ')}
          ELSE ${Prisma.raw(quoteIdentifier(rankColumn))}
        END
      WHERE permission_key IN (${Prisma.join(keys)})
    `,
  )
}

async function updateLegacyPermissionFields(
  db: RawDb,
  rankId: number,
  fields: Record<string, string | number>,
) {
  const columns = await getTableColumns(db, 'permissions')
  const existingFields = Object.fromEntries(
    Object.entries(fields).filter(([key]) => columns.has(key)),
  )
  if (Object.keys(existingFields).length === 0) return 0
  return updateTableFields(db, 'permissions', rankId, existingFields)
}

async function ensurePermissionRankColumn(db: RawDb, rankId: number) {
  const rankColumn = getRankPermissionColumn(rankId)
  const exists = await db.$queryRaw<{ c: bigint | number }[]>(
    Prisma.sql`
      SELECT COUNT(*) AS c
      FROM information_schema.columns
      WHERE table_schema = DATABASE()
        AND table_name = 'permission_definitions'
        AND column_name = ${rankColumn}
    `,
  )
  if (Number(exists[0]?.c ?? 0) > 0) return

  await db.$executeRaw(
    Prisma.sql`
      ALTER TABLE permission_definitions
      ADD COLUMN ${Prisma.raw(quoteIdentifier(rankColumn))} TINYINT UNSIGNED NOT NULL DEFAULT 0
    `,
  )
}

async function resetPermissionRankColumn(db: RawDb, rankId: number) {
  const rankColumn = getRankPermissionColumn(rankId)
  await db.$executeRaw(
    Prisma.sql`
      UPDATE permission_definitions
      SET ${Prisma.raw(quoteIdentifier(rankColumn))} = 0
    `,
  )
}

async function getTableColumns(db: RawDb, table: string) {
  const rows = await db.$queryRaw<{ column_name: string }[]>(
    Prisma.sql`
      SELECT column_name
      FROM information_schema.columns
      WHERE table_schema = DATABASE()
        AND table_name = ${table}
    `,
  )
  return new Set(rows.map((row) => row.column_name))
}

function quoteIdentifier(identifier: string) {
  if (!VALID_KEY.test(identifier)) throw new Error('Invalid identifier')
  return `\`${identifier}\``
}