import { mkdtemp, rm } from 'node:fs/promises'
import { tmpdir } from 'node:os'
import path from 'node:path'
import { afterAll, describe, expect, it } from 'vitest'
import { eq } from 'drizzle-orm'
import { openGameDb, type GameDb } from '@/lib/db/client'
import * as schema from '@/lib/db/schema'
import { BASE_CAPACITY, BASE_LEVEL, BUILD_PART_COST, MAX_CAPACITY, MAX_LEVEL, SHIP_TYPES } from './ship-costs'
import { buildSystem, expandSystem, getShipState, resolveShipBuildTask, resolveShipExpandTask, resolveShipUpgradeTask, spendItems, upgradeSystem, type ShipState } from './ship'
import { SCHEMA_VERSION } from './save'
import { TECHS } from './tech'
import type { Task } from './tasks'

const dirs: string[] = []

async function freshFile(): Promise<{ db: GameDb; file: string }> {
  const dir = await mkdtemp(path.join(tmpdir(), 'sw-ship-test-'))
  dirs.push(dir)
  const file = path.join(dir, 'test.db')
  return { db: await openGameDb(file), file }
}

afterAll(async () => {
  for (const d of dirs) await rm(d, { recursive: true, force: true })
})

async function addItem(db: GameDb, kind: 'resource' | 'part', name: string, qty: number): Promise<void> {
  const [save] = await db.db.select().from(schema.saves).limit(1)
  await db.db.insert(schema.inventoryItems).values({ saveId: save.id, kind, name, qty })
}

const systemOf = (state: ShipState, type: string): ShipState['systems'][number] => state.systems.find((s) => s.type === type)!

describe('getShipState', () => {
  it('new game: starting ship in display order — core types built at base values, WEAPONS unbuilt', async () => {
    const { db } = await freshFile()
    const state = await getShipState(db)

    expect(state.systems.map((s) => s.type)).toEqual(SHIP_TYPES.map((t) => t.type)) // display order follows SHIP_TYPES
    for (const def of SHIP_TYPES) {
      const row = systemOf(state, def.type)
      if (def.builtAtStart) {
        expect(row.built).toBe(true)
        expect({ level: row.level, capacity: row.capacity }).toEqual({ level: BASE_LEVEL, capacity: BASE_CAPACITY })
      } else {
        expect(row.built).toBe(false) // unbuilt until a BUILD action
        expect(row.level).toBe(0)
        expect(row.capacity).toBe(0)
      }
    }
    expect(state.inventory).toEqual([])
    expect(state.turn).toBe(0)
  })
})

describe('upgradeSystem', () => {
  it('rejects with 422 and mutates nothing when the hold is empty', async () => {
    const { db } = await freshFile()
    const before = await getShipState(db)
    const reactorId = systemOf(before, 'REACTOR').id

    await expect(upgradeSystem(db, reactorId)).rejects.toMatchObject({ status: 422 })

    const after = await getShipState(db)
    expect(systemOf(after, 'REACTOR').level).toBe(BASE_LEVEL) // no level change…
    expect(after.turn).toBe(before.turn) // …and no turn spent on a failed action
  })

  it('rejects unknown systemId with 404 and unbuilt systems with 409', async () => {
    const { db } = await freshFile()
    await getShipState(db)
    await expect(upgradeSystem(db, 999)).rejects.toMatchObject({ status: 404 })
    const weaponsId = systemOf(await getShipState(db), 'WEAPONS').id
    await expect(upgradeSystem(db, weaponsId)).rejects.toMatchObject({ status: 409 })
  })

  it('consumes the cost from the oldest resource row first (deleting rows that hit zero), costs a turn and writes an event', async () => {
    const { db } = await freshFile()
    await getShipState(db)
    await addItem(db, 'resource', 'IRON ORE', 1) // oldest — fully consumed by the cost of 1
    await addItem(db, 'resource', 'CRYSTAL DUST', 5)

    const reactorId = systemOf(await getShipState(db), 'REACTOR').id
    const state = await upgradeSystem(db, reactorId) // level 1 → cost 1 resource

    expect(systemOf(state, 'REACTOR').level).toBe(BASE_LEVEL + 1)
    expect((await db.db.select().from(schema.inventoryItems)).map((i) => [i.name, i.qty])).toEqual([['CRYSTAL DUST', 5]]) // IRON ORE row deleted
    expect(state.turn).toBe(1)

    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'upgrade')!
    expect(event.turn).toBe(1)
    expect(event.message).toContain('REACTOR')
  })

  it('caps at MAX_LEVEL with 409', async () => {
    const { db } = await freshFile()
    await getShipState(db)
    const reactorId = systemOf(await getShipState(db), 'REACTOR').id
    await db.db.update(schema.shipSystems).set({ level: MAX_LEVEL }).where(eq(schema.shipSystems.id, reactorId)) // cost path covered above

    await expect(upgradeSystem(db, reactorId)).rejects.toMatchObject({ status: 409 })
    expect((await getShipState(db)).turn).toBe(0)
  })
})

describe('expandSystem', () => {
  it('raises capacity by one for `capacity` resources; caps at MAX_CAPACITY with 409', async () => {
    const { db } = await freshFile()
    await getShipState(db)
    await addItem(db, 'resource', 'IRON ORE', BASE_CAPACITY + 1) // cost is the current capacity (2), one left over

    const hullId = systemOf(await getShipState(db), 'HULL').id
    const state = await expandSystem(db, hullId)
    expect(systemOf(state, 'HULL').capacity).toBe(BASE_CAPACITY + 1)
    expect((await db.db.select().from(schema.inventoryItems)).map((i) => [i.name, i.qty])).toEqual([['IRON ORE', 1]])

    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'expand')!
    expect(event.turn).toBe(1)
    expect(event.message).toContain('HULL')

    await db.db.update(schema.shipSystems).set({ capacity: MAX_CAPACITY }).where(eq(schema.shipSystems.id, hullId))
    await expect(expandSystem(db, hullId)).rejects.toMatchObject({ status: 409 })
  })

  it('rejects unknown systemId with 404 and unbuilt systems with 409', async () => {
    const { db } = await freshFile()
    await getShipState(db)
    await expect(expandSystem(db, 999)).rejects.toMatchObject({ status: 404 })
    const weaponsId = systemOf(await getShipState(db), 'WEAPONS').id
    await expect(expandSystem(db, weaponsId)).rejects.toMatchObject({ status: 409 })
  })
})

describe('buildSystem', () => {
  it('builds an unbuilt type at base values for a flat parts cost; a second build is 409 and unknown types are 404', async () => {
    const { db } = await freshFile()
    await getShipState(db)

    // WEAPONS is gated behind the WEAPONS SYSTEMS tech (issue #9) — research it directly so this
    // test keeps covering the cost path; the gate itself is covered in research.test.ts.
    await db.db.update(schema.tech).set({ researched: true }).where(eq(schema.tech.slug, 'WEAPONS_SYSTEMS'))

    await expect(buildSystem(db, 'WEAPONS')).rejects.toMatchObject({ status: 422 }) // no parts in the hold yet

    await addItem(db, 'part', 'SERVO ACTUATOR', BUILD_PART_COST)
    const state = await buildSystem(db, 'WEAPONS')
    const weapons = systemOf(state, 'WEAPONS')
    expect(weapons.built).toBe(true)
    expect({ level: weapons.level, capacity: weapons.capacity }).toEqual({ level: BASE_LEVEL, capacity: BASE_CAPACITY })
    expect(await db.db.select().from(schema.inventoryItems)).toHaveLength(0) // parts row deleted
    expect(state.turn).toBe(1)

    const event = (await db.db.select().from(schema.events)).find((e) => e.type === 'build')!
    expect(event.turn).toBe(1)
    expect(event.message).toContain('WEAPONS')

    await expect(buildSystem(db, 'WEAPONS')).rejects.toMatchObject({ status: 409 }) // already built
    await expect(buildSystem(db, 'SHIELDS')).rejects.toMatchObject({ status: 404 }) // not a known type
  })
})

// --- A/B: resolvers vs the legacy immediate ship actions (Task 4a) ---------------------
const T0 = '2026-10-01T00:00:00.000Z'

// Stamped save (no backfill), the full ship per SHIP_TYPES, the full tech tree with
// WEAPONS_SYSTEMS researched (unlocks the BUILD row). Identical build per world → ids line up.
async function buildShipFixture(db: GameDb): Promise<void> {
  const [save] = await db.db.insert(schema.saves).values({ seed: '42', turn: 0, createdAt: T0, schemaVersion: SCHEMA_VERSION }).returning()
  for (const def of SHIP_TYPES) {
    await db.db.insert(schema.shipSystems).values({ saveId: save.id, type: def.type, level: def.builtAtStart ? BASE_LEVEL : 0, capacity: def.builtAtStart ? BASE_CAPACITY : 0 })
  }
  for (const def of TECHS) {
    await db.db.insert(schema.tech).values({ saveId: save.id, slug: def.slug, name: def.name, costKind: def.costKind, costQty: def.costQty, prerequisites: def.prereqs.join(','), effect: def.effect, researched: def.slug === 'WEAPONS_SYSTEMS' })
  }
}

const task = (type: 'SHIP_UPGRADE' | 'SHIP_EXPAND' | 'SHIP_BUILD', payload: object): Task =>
  ({ id: 0, saveId: 0, type, payload: JSON.stringify(payload), leadCrewId: 0, helpers: [], duration: 0, remaining: 0, status: 'ACTIVE', queuedAtTurn: 0 })

async function snapshot(db: GameDb): Promise<string> {
  const [saves, systems, routes, planets, inventory, crew, ship, tech, missions, events] = await Promise.all([
    db.db.select({ id: schema.saves.id, seed: schema.saves.seed, turn: schema.saves.turn, schemaVersion: schema.saves.schemaVersion }).from(schema.saves),
    db.db.select().from(schema.solarSystems),
    db.db.select().from(schema.jumpRoutes),
    db.db.select().from(schema.planets),
    db.db.select().from(schema.inventoryItems),
    db.db.select().from(schema.crew),
    db.db.select().from(schema.shipSystems),
    db.db.select().from(schema.tech),
    db.db.select().from(schema.missions),
    db.db.select({ id: schema.events.id, turn: schema.events.turn, type: schema.events.type, message: schema.events.message }).from(schema.events),
  ])
  return JSON.stringify({ saves, systems, routes, planets, inventory, crew, ship, tech, missions, events })
}

describe('resolveShip* (A/B against the immediate actions)', () => {
  // A = legacy immediate action (validates, deducts the cost, +1 turn, effect, event).
  // B = the queued shape: the cost is deducted up front (queueTask did it at queue time —
  // Task 3), the tick advanced the turn (Task 4b), then the resolver applies the effect.
  // Same starting world → byte-identical end states.

  it('UPGRADE: lands exactly what upgradeSystem lands', async () => {
    const { db: a } = await freshFile()
    const { db: b } = await freshFile()
    await buildShipFixture(a)
    await buildShipFixture(b)
    await addItem(a, 'resource', 'IRON ORE', 1) // level 1 → cost 1
    await addItem(b, 'resource', 'IRON ORE', 1)

    const reactorId = systemOf(await getShipState(a), 'REACTOR').id
    await upgradeSystem(a, reactorId)
    await spendItems(b, 1, 'resource', 1) // the queue-time deduction
    await b.db.update(schema.saves).set({ turn: 1 }).where(eq(schema.saves.id, 1))
    await resolveShipUpgradeTask(b, task('SHIP_UPGRADE', { systemId: reactorId }))

    expect(await snapshot(b)).toEqual(await snapshot(a))
    const ev = (await b.db.select({ turn: schema.events.turn, type: schema.events.type, message: schema.events.message }).from(schema.events)).find((e) => e.type === 'upgrade')!
    expect(ev.turn).toBe(1)
    expect(ev.message).toBe('Upgraded REACTOR to level 2 (cost: 1× resources)')
  })

  it('EXPAND: lands exactly what expandSystem lands', async () => {
    const { db: a } = await freshFile()
    const { db: b } = await freshFile()
    await buildShipFixture(a)
    await buildShipFixture(b)
    await addItem(a, 'resource', 'CRYSTAL DUST', 2) // capacity 2 → cost 2
    await addItem(b, 'resource', 'CRYSTAL DUST', 2)

    const hullId = systemOf(await getShipState(a), 'HULL').id
    await expandSystem(a, hullId)
    await spendItems(b, 1, 'resource', 2)
    await b.db.update(schema.saves).set({ turn: 1 }).where(eq(schema.saves.id, 1))
    await resolveShipExpandTask(b, task('SHIP_EXPAND', { systemId: hullId }))

    expect(await snapshot(b)).toEqual(await snapshot(a))
    const ev = (await b.db.select({ turn: schema.events.turn, type: schema.events.type, message: schema.events.message }).from(schema.events)).find((e) => e.type === 'expand')!
    expect(ev.turn).toBe(1)
    expect(ev.message).toBe('Expanded HULL capacity to 3 (cost: 2× resources)')
  })

  it('BUILD: lands exactly what buildSystem lands', async () => {
    const { db: a } = await freshFile()
    const { db: b } = await freshFile()
    await buildShipFixture(a)
    await buildShipFixture(b)
    await addItem(a, 'part', 'SERVO ACTUATOR', 3)
    await addItem(b, 'part', 'SERVO ACTUATOR', 3)

    await buildSystem(a, 'WEAPONS')
    await spendItems(b, 1, 'part', 3)
    await b.db.update(schema.saves).set({ turn: 1 }).where(eq(schema.saves.id, 1))
    await resolveShipBuildTask(b, task('SHIP_BUILD', { type: 'WEAPONS' }))

    expect(await snapshot(b)).toEqual(await snapshot(a))
    const ev = (await b.db.select({ turn: schema.events.turn, type: schema.events.type, message: schema.events.message }).from(schema.events)).find((e) => e.type === 'build')!
    expect(ev.turn).toBe(1)
    expect(ev.message).toBe('Built WEAPONS at base values (cost: 3× parts)')
  })

  it('guards: 404 unknown, 409 unbuilt / max level / max capacity / gate / already built', async () => {
    const { db } = await freshFile()
    await buildShipFixture(db)
    const state = await getShipState(db)
    const reactorId = systemOf(state, 'REACTOR').id
    const hullId = systemOf(state, 'HULL').id
    const weaponsId = systemOf(state, 'WEAPONS').id
    await db.db.update(schema.saves).set({ turn: 1 }).where(eq(schema.saves.id, 1))

    await expect(resolveShipUpgradeTask(db, task('SHIP_UPGRADE', { systemId: 999 }))).rejects.toMatchObject({ status: 404, message: 'Unknown ship system 999' })
    await expect(resolveShipUpgradeTask(db, task('SHIP_UPGRADE', { systemId: weaponsId }))).rejects.toMatchObject({ status: 409, message: 'WEAPONS is not built' })
    await db.db.update(schema.shipSystems).set({ level: MAX_LEVEL }).where(eq(schema.shipSystems.id, reactorId))
    await expect(resolveShipUpgradeTask(db, task('SHIP_UPGRADE', { systemId: reactorId }))).rejects.toMatchObject({ status: 409, message: `REACTOR is at max level (${MAX_LEVEL})` })

    await expect(resolveShipExpandTask(db, task('SHIP_EXPAND', { systemId: 999 }))).rejects.toMatchObject({ status: 404, message: 'Unknown ship system 999' })
    await db.db.update(schema.shipSystems).set({ capacity: MAX_CAPACITY }).where(eq(schema.shipSystems.id, hullId))
    await expect(resolveShipExpandTask(db, task('SHIP_EXPAND', { systemId: hullId }))).rejects.toMatchObject({ status: 409, message: `HULL is at max capacity (${MAX_CAPACITY})` })

    await expect(resolveShipBuildTask(db, task('SHIP_BUILD', { type: 'SHIELDS' }))).rejects.toMatchObject({ status: 404, message: 'Unknown ship system type SHIELDS' })
    await db.db.update(schema.tech).set({ researched: false }).where(eq(schema.tech.slug, 'WEAPONS_SYSTEMS'))
    await expect(resolveShipBuildTask(db, task('SHIP_BUILD', { type: 'WEAPONS' }))).rejects.toMatchObject({ status: 409, message: 'Building WEAPONS requires the WEAPONS SYSTEMS tech' })
    await expect(resolveShipBuildTask(db, task('SHIP_BUILD', { type: 'HULL' }))).rejects.toMatchObject({ status: 409, message: 'HULL is already built' })
  })
})