import { afterEach, beforeEach, describe, expect, it } from 'vitest'
import { readFile, rm, utimes, writeFile, mkdir } from 'fs/promises'
import { existsSync } from 'fs'
import { tmpdir } from 'os'
import { basename, join } from 'path'

import {
  CACHE_VERSION,
  PROVIDER_ENV_VARS,
  type CachedCall,
  type CachedFile,
  type CachedTurn,
  type FileFingerprint,
  type SessionCache,
  cleanupOrphanedTempFiles,
  clearLoadCacheMemo,
  computeEnvFingerprint,
  emptyCache,
  fingerprintFile,
  loadCache,
  mergeCallByDedupKey,
  reconcileFile,
  saveCache,
  sessionCacheDir,
} from '../src/session-cache.js'
import { readCacheOnDisk, writeCacheOnDisk } from './fixtures/session-cache-io.js'

// Version-suffixed directory (e.g. session-cache.v8) the cache now writes to.
const CACHE_DIR = () => basename(sessionCacheDir())

const TMP_DIR = join(tmpdir(), `codeburn-scache-test-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`)

beforeEach(() => {
  process.env['CODEBURN_CACHE_DIR'] = TMP_DIR
})

afterEach(async () => {
  if (existsSync(TMP_DIR)) await rm(TMP_DIR, { recursive: true })
})

function makeCall(overrides: Partial<CachedCall> = {}): CachedCall {
  return {
    provider: 'claude',
    model: 'claude-sonnet-4-20250514',
    usage: {
      inputTokens: 1000,
      outputTokens: 500,
      cacheCreationInputTokens: 0,
      cacheReadInputTokens: 0,
      cachedInputTokens: 0,
      reasoningTokens: 0,
      webSearchRequests: 0,
      cacheCreationOneHourTokens: 0,
    },
    speed: 'standard',
    timestamp: '2026-05-15T10:00:00Z',
    tools: ['Read', 'Edit'],
    bashCommands: [],
    skills: [],
    deduplicationKey: 'msg-abc123',
    ...overrides,
  }
}

function makeTurn(overrides: Partial<CachedTurn> = {}): CachedTurn {
  return {
    timestamp: '2026-05-15T10:00:00Z',
    sessionId: 'sess-1',
    userMessage: 'fix the bug',
    calls: [makeCall()],
    ...overrides,
  }
}

function makeCachedFile(overrides: Partial<CachedFile> = {}): CachedFile {
  return {
    fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
    mcpInventory: [],
    turns: [makeTurn()],
    ...overrides,
  }
}

// ── emptyCache ─────────────────────────────────────────────────────────

describe('emptyCache', () => {
  it('returns a valid empty cache', () => {
    const cache = emptyCache()
    expect(cache.version).toBe(CACHE_VERSION)
    expect(cache.providers).toEqual({})
  })
})

// ── loadCache / saveCache ──────────────────────────────────────────────

describe('loadCache / saveCache', () => {
  it('returns empty cache when no file exists', async () => {
    const cache = await loadCache()
    expect(cache.version).toBe(CACHE_VERSION)
    expect(cache.providers).toEqual({})
  })

  it('round-trips a cache through save and load', async () => {
    const cache: SessionCache = {
      version: CACHE_VERSION,
      providers: {
        claude: {
          envFingerprint: 'abc123',
          files: {
            '/path/to/session.jsonl': makeCachedFile(),
          },
        },
      },
    }

    await saveCache(cache)
    const loaded = await loadCache()
    expect(loaded).toEqual(cache)
  })

  it('persists a failed-parse marker across save/load (negative-result cache)', async () => {
    const cache: SessionCache = {
      version: CACHE_VERSION,
      providers: {
        pi: {
          envFingerprint: 'abc123',
          files: {
            '/path/to/bad.jsonl': makeCachedFile({ turns: [], failed: true }),
          },
        },
      },
    }

    await saveCache(cache)
    const loaded = await loadCache()
    // The `failed` flag and empty turns survive validation + load, so the file
    // stays skipped on the next run instead of being re-read and re-thrown.
    expect(loaded.providers['pi']?.files['/path/to/bad.jsonl']?.failed).toBe(true)
    expect(loaded.providers['pi']?.files['/path/to/bad.jsonl']?.turns).toEqual([])
  })

  it('preserves the estimated-cost flag through save/load; a measured call stays unflagged', async () => {
    const cache: SessionCache = {
      version: CACHE_VERSION,
      providers: {
        warp: {
          envFingerprint: 'abc123',
          files: {
            '/path/to/warp.sqlite': makeCachedFile({
              turns: [makeTurn({ calls: [
                makeCall({ deduplicationKey: 'est', costUSD: 0.5, isEstimated: true }),
                makeCall({ deduplicationKey: 'measured', costUSD: 0.5 }),
              ] })],
            }),
          },
        },
      },
    }

    await saveCache(cache)
    const loaded = await loadCache()
    const calls = loaded.providers['warp']?.files['/path/to/warp.sqlite']?.turns[0]?.calls
    expect(calls?.[0]?.isEstimated).toBe(true)
    // A call with no flag round-trips as undefined, not silently coerced to true.
    expect(calls?.[1]?.isEstimated).toBeUndefined()
  })

  it('returns empty cache on version mismatch', async () => {
    const bad: SessionCache = { version: 999, providers: { claude: { envFingerprint: 'x', files: {} } } }
    await mkdir(TMP_DIR, { recursive: true })
    await writeFile(join(TMP_DIR, 'session-cache.json'), JSON.stringify(bad))

    const loaded = await loadCache()
    expect(loaded.version).toBe(CACHE_VERSION)
    expect(loaded.providers).toEqual({})
  })

  it('returns empty cache on corrupt JSON', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    await writeFile(join(TMP_DIR, 'session-cache.json'), '{broken')

    const loaded = await loadCache()
    expect(loaded.version).toBe(CACHE_VERSION)
    expect(loaded.providers).toEqual({})
  })

  it('atomic write does not leave partial file on error', async () => {
    await saveCache(emptyCache())
    expect(await readCacheOnDisk()).toEqual(emptyCache())
  })
})

// ── versioned filename + legacy adoption ───────────────────────────────

describe('versioned cache file + legacy adoption', () => {
  function validCache(): SessionCache {
    return {
      version: CACHE_VERSION,
      complete: false,
      providers: { claude: { envFingerprint: 'abc123', files: { '/path/to/session.jsonl': makeCachedFile() } } },
    }
  }

  it('writes and reads the version-suffixed directory, never the legacy name', async () => {
    expect(basename(sessionCacheDir())).toBe(`session-cache.v${CACHE_VERSION}`)
    await saveCache(validCache())
    expect(existsSync(sessionCacheDir())).toBe(true)
    expect(existsSync(join(TMP_DIR, 'session-cache.json'))).toBe(false)
    expect(await loadCache()).toEqual(validCache())
  })

  it('adopts a matching-version legacy file once, without deleting or rewriting it', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const legacy = join(TMP_DIR, 'session-cache.json')
    await writeFile(legacy, JSON.stringify(validCache()))

    // Versioned directory absent → adopt-copy from legacy on first load.
    expect(await loadCache()).toEqual(validCache())
    expect(existsSync(sessionCacheDir())).toBe(true)
    // Legacy left intact (not deleted, not rewritten).
    expect(existsSync(legacy)).toBe(true)
    expect(JSON.parse(await readFile(legacy, 'utf-8'))).toEqual(validCache())

    // Adoption is one-time: a later legacy edit is ignored once the versioned
    // file exists.
    const mutated: SessionCache = { version: CACHE_VERSION, providers: { codex: { envFingerprint: 'zzz', files: {} } } }
    await writeFile(legacy, JSON.stringify(mutated))
    expect(await readCacheOnDisk()).toEqual(validCache())
  })

  it('ignores a different-version legacy file and never touches it', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const legacy = join(TMP_DIR, 'session-cache.json')
    const stale = { version: 999, providers: { claude: { envFingerprint: 'x', files: {} } } }
    await writeFile(legacy, JSON.stringify(stale))

    expect((await loadCache()).providers).toEqual({})
    // No versioned directory adopted; legacy left byte-intact.
    expect(existsSync(sessionCacheDir())).toBe(false)
    expect(JSON.parse(await readFile(legacy, 'utf-8'))).toEqual(stale)
  })

  it('saveCache never creates or overwrites a pre-existing legacy file', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const legacy = join(TMP_DIR, 'session-cache.json')
    const legacyContent = JSON.stringify({ version: CACHE_VERSION, providers: {} })
    await writeFile(legacy, legacyContent)

    await saveCache(validCache())
    // The shards hold the new data; the legacy file is byte-untouched.
    expect(await readFile(legacy, 'utf-8')).toBe(legacyContent)
    expect(await readCacheOnDisk()).toEqual(validCache())
  })
})

// ── computeEnvFingerprint ──────────────────────────────────────────────

describe('computeEnvFingerprint', () => {
  it('returns stable hash for same env', () => {
    const a = computeEnvFingerprint('claude')
    const b = computeEnvFingerprint('claude')
    expect(a).toBe(b)
    expect(a).toHaveLength(16)
  })

  it('changes when env var changes', () => {
    const before = computeEnvFingerprint('claude')
    process.env['CLAUDE_CONFIG_DIR'] = '/tmp/different'
    const after = computeEnvFingerprint('claude')
    expect(before).not.toBe(after)
  })

  it('returns stable hash for unknown provider (no env vars)', () => {
    const a = computeEnvFingerprint('unknown-provider')
    const b = computeEnvFingerprint('unknown-provider')
    expect(a).toBe(b)
  })

  it('includes parser versions in provider fingerprints', () => {
    expect(computeEnvFingerprint('claude')).not.toBe(computeEnvFingerprint('unknown-provider'))
    expect(computeEnvFingerprint('copilot')).not.toBe(computeEnvFingerprint('unknown-provider'))
    expect(computeEnvFingerprint('kiro')).not.toBe(computeEnvFingerprint('unknown-provider'))
    expect(computeEnvFingerprint('warp')).not.toBe(computeEnvFingerprint('unknown-provider'))
  })
})

// ── provider env overrides invalidate the fingerprint (#920) ─────────────

describe('provider env overrides invalidate the fingerprint (#920)', () => {
  // Nine providers honored an env var that relocates where discovery looks
  // without the var being declared in PROVIDER_ENV_VARS, so
  // computeEnvFingerprint did not hash it and the cache section survived the
  // change: sessions parsed from the old root kept being reported and the new
  // root was never read. Each pair below must change the fingerprint when the
  // var is set. codex/CODEX_HOME is the control — it already worked and must
  // keep working.
  const CASES: Array<[provider: string, varName: string]> = [
    ['kiro', 'KIRO_HOME'],
    ['grok', 'GROK_HOME'],
    ['kimi', 'KIMI_SHARE_DIR'],
    ['mux', 'MUX_ROOT'],
    ['mistral-vibe', 'VIBE_HOME'],
    ['zerostack', 'ZS_DATA_DIR'],
    ['codebuff', 'CODEBUFF_DATA_DIR'],
    ['goose', 'GOOSE_PATH_ROOT'],
    ['crush', 'CRUSH_GLOBAL_DATA'],
    ['codex', 'CODEX_HOME'],
  ]
  const VARS = CASES.map(([, varName]) => varName)

  // Save and restore every var we touch (beforeEach/afterEach), so a leaked
  // env var never breaks unrelated tests in the same worker — and an ambient
  // value never makes the "unset" case a lie.
  const saved = new Map<string, string | undefined>()

  beforeEach(() => {
    for (const varName of VARS) {
      saved.set(varName, process.env[varName])
      delete process.env[varName]
    }
  })

  afterEach(() => {
    for (const varName of VARS) {
      const original = saved.get(varName)
      if (original === undefined) delete process.env[varName]
      else process.env[varName] = original
    }
  })

  for (const [provider, varName] of CASES) {
    it(`changes the ${provider} fingerprint when ${varName} is set`, () => {
      const unset = computeEnvFingerprint(provider)
      process.env[varName] = '/tmp/codeburn-920-override'
      const set = computeEnvFingerprint(provider)
      expect(set).not.toBe(unset)
      // Round trip: restoring the variable to its original state restores the
      // original fingerprint, so the hash is a pure function of the
      // environment.
      delete process.env[varName]
      expect(computeEnvFingerprint(provider)).toBe(unset)
    })
  }

  it('changes the vercel-gateway fingerprint when AI_GATEWAY_API_KEY is set', () => {
    const prev = process.env['AI_GATEWAY_API_KEY']
    try {
      const unset = computeEnvFingerprint('vercel-gateway')
      process.env['AI_GATEWAY_API_KEY'] = 'sk-live-secret-abc'
      const set = computeEnvFingerprint('vercel-gateway')
      expect(set).not.toBe(unset)
      delete process.env['AI_GATEWAY_API_KEY']
      expect(computeEnvFingerprint('vercel-gateway')).toBe(unset)
    } finally {
      if (prev === undefined) delete process.env['AI_GATEWAY_API_KEY']
      else process.env['AI_GATEWAY_API_KEY'] = prev
    }
  })

  // Copilot is deliberately NOT declared in PROVIDER_ENV_VARS (Ruling 1 of
  // lane 04): its OTel discovery returns one source per DB file
  // ({ path: dbPath }, src/providers/copilot.ts:1935), and the durable
  // carry-forward in getOrCreateProviderSection (src/parser.ts:2650) drops
  // every cached entry whose source still exists on a fingerprint change — so
  // declaring any CODEBURN_COPILOT_* var would force a re-parse that destroys
  // conversations Copilot has since pruned from the DB, which only the cache
  // still holds. The fingerprint must therefore NOT move when one is set.
  // This reads as intent, not as an oversight — and the assertions below pin
  // the WHOLE invariant (no entry at all, plus every one of the nine deferred
  // reads), so a future "completing" edit fails a test instead of silently
  // re-opening the durable history-loss path.
  describe('copilot is deliberately undeclared in PROVIDER_ENV_VARS', () => {
    it('has no PROVIDER_ENV_VARS entry at all', () => {
      expect(PROVIDER_ENV_VARS['copilot']).toBeUndefined()
    })

    // The nine reads copilot.ts performs whose declaration is deferred (each
    // is allowlisted in tests/provider-env-declarations.test.ts): setting any
    // of them must leave the copilot fingerprint untouched.
    const DEFERRED_COPILOT_VARS = [
      'CODEBURN_COPILOT_SESSION_STATE_DIR',
      'CODEBURN_COPILOT_OTEL_DB',
      'CODEBURN_COPILOT_JETBRAINS_DIR',
      'CODEBURN_COPILOT_WS_STORAGE_DIR',
      'CODEBURN_COPILOT_GLOBAL_STORAGE_DIR',
      'CODEBURN_COPILOT_DISABLE_OTEL',
      'APPDATA',
      'LOCALAPPDATA',
      'XDG_CONFIG_HOME',
    ]

    for (const varName of DEFERRED_COPILOT_VARS) {
      it(`does not move the copilot fingerprint when ${varName} is set (deliberately undeclared)`, () => {
        const prev = process.env[varName]
        try {
          const before = computeEnvFingerprint('copilot')
          process.env[varName] = `/tmp/codeburn-copilot-920/${varName}`
          expect(computeEnvFingerprint('copilot')).toBe(before)
          delete process.env[varName]
          expect(computeEnvFingerprint('copilot')).toBe(before)
        } finally {
          if (prev === undefined) delete process.env[varName]
          else process.env[varName] = prev
        }
      })
    }
  })
})

// ── fingerprintFile ────────────────────────────────────────────────────

describe('fingerprintFile', () => {
  it('returns fingerprint for existing file', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const filePath = join(TMP_DIR, 'test.jsonl')
    await writeFile(filePath, 'line1\nline2\n')

    const fp = await fingerprintFile(filePath)
    expect(fp).not.toBeNull()
    expect(fp!.sizeBytes).toBe(12)
    expect(fp!.dev).toBeGreaterThan(0)
    expect(fp!.ino).toBeGreaterThan(0)
    expect(fp!.mtimeMs).toBeGreaterThan(0)
  })

  it('returns null for non-existent file', async () => {
    const fp = await fingerprintFile('/no/such/file')
    expect(fp).toBeNull()
  })

  it('resolves compound path with # separator (Cursor workspace)', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const filePath = join(TMP_DIR, 'state.vscdb')
    await writeFile(filePath, 'cursor-data')

    const fp = await fingerprintFile(`${filePath}#cursor-ws=__orphan__`)
    expect(fp).not.toBeNull()
    expect(fp!.sizeBytes).toBe(11)
  })

  it('resolves compound path with : separator (OpenCode session)', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const filePath = join(TMP_DIR, 'opencode.db')
    await writeFile(filePath, 'opencode-data')

    const fp = await fingerprintFile(`${filePath}:ses_abc123`)
    expect(fp).not.toBeNull()
    expect(fp!.sizeBytes).toBe(13)
  })

  it('returns null when base file does not exist for compound path', async () => {
    const fp = await fingerprintFile('/no/such/file.db#cursor-ws=workspace')
    expect(fp).toBeNull()
  })

  it('prefers # separator over : when both present', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const filePath = join(TMP_DIR, 'state.vscdb')
    await writeFile(filePath, 'both-seps')

    // Path has both # and : — should strip at # first and find the base file
    const fp = await fingerprintFile(`${filePath}#cursor-ws=ws:extra-colon`)
    expect(fp).not.toBeNull()
    expect(fp!.sizeBytes).toBe(9)
  })

  // SQLite WAL mode parks committed writes in `<db>-wal`; the main file's
  // stat only moves on checkpoint, which a long-lived writer defers for
  // hours. A fingerprint from the main file alone reports data older than
  // what is really committed (issue #913). The WAL sibling must be folded in.
  it('folds -wal sibling into a # compound fingerprint (Hermes session)', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const dbPath = join(TMP_DIR, 'state.db')
    await writeFile(dbPath, 'main-db')
    const past = new Date(Date.now() - 48 * 3600 * 1000)
    await utimes(dbPath, past, past)
    await writeFile(`${dbPath}-wal`, 'wal-frames')

    const fp = await fingerprintFile(`${dbPath}#hermes-session=abc`)
    expect(fp).not.toBeNull()
    // mtime: the fresh WAL wins over the checkpoint-stale main file.
    expect(fp!.mtimeMs).toBeGreaterThan(past.getTime() + 3600 * 1000)
    // size: main + wal, so WAL growth alone changes the fingerprint.
    expect(fp!.sizeBytes).toBe('main-db'.length + 'wal-frames'.length)
  })

  it('folds -wal sibling into a : compound fingerprint (OpenCode session)', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const dbPath = join(TMP_DIR, 'opencode.db')
    await writeFile(dbPath, 'oc-db')
    const past = new Date(Date.now() - 48 * 3600 * 1000)
    await utimes(dbPath, past, past)
    await writeFile(`${dbPath}-wal`, 'oc-wal')

    const fp = await fingerprintFile(`${dbPath}:ses_abc123`)
    expect(fp).not.toBeNull()
    expect(fp!.mtimeMs).toBeGreaterThan(past.getTime() + 3600 * 1000)
    expect(fp!.sizeBytes).toBe('oc-db'.length + 'oc-wal'.length)
  })

  it('folds -wal sibling into a bare SQLite path (copilot agent-traces.db)', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const dbPath = join(TMP_DIR, 'agent-traces.db')
    await writeFile(dbPath, 'traces')
    const past = new Date(Date.now() - 48 * 3600 * 1000)
    await utimes(dbPath, past, past)
    await writeFile(`${dbPath}-wal`, 'traces-wal')

    const fp = await fingerprintFile(dbPath)
    expect(fp).not.toBeNull()
    expect(fp!.mtimeMs).toBeGreaterThan(past.getTime() + 3600 * 1000)
    expect(fp!.sizeBytes).toBe('traces'.length + 'traces-wal'.length)
  })

  it('keeps compound fingerprints working when no -wal sibling exists', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const dbPath = join(TMP_DIR, 'state.db')
    await writeFile(dbPath, 'main-only')

    const fp = await fingerprintFile(`${dbPath}#hermes-session=abc`)
    expect(fp).not.toBeNull()
    expect(fp!.sizeBytes).toBe('main-only'.length)
  })

  it('does not fold sibling files into non-SQLite fingerprints', async () => {
    await mkdir(TMP_DIR, { recursive: true })
    const filePath = join(TMP_DIR, 'session.jsonl')
    await writeFile(filePath, 'jsonl-data')
    // A stray neighbor that happens to match the -wal naming must not leak
    // into a transcript fingerprint (offset-based append detection relies on
    // sizeBytes being the transcript's real byte length).
    await writeFile(`${filePath}-wal`, 'stray')

    const fp = await fingerprintFile(filePath)
    expect(fp).not.toBeNull()
    expect(fp!.sizeBytes).toBe('jsonl-data'.length)
  })
})

// ── reconcileFile ──────────────────────────────────────────────────────

describe('reconcileFile', () => {
  it('returns "new" when no cached entry', () => {
    const fp: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 }
    expect(reconcileFile(fp, undefined)).toEqual({ action: 'new' })
  })

  it('returns "unchanged" when all fields match', () => {
    const fp: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 }
    const cached = makeCachedFile({ fingerprint: { ...fp } })
    expect(reconcileFile(fp, cached)).toEqual({ action: 'unchanged' })
  })

  it('returns "appended" when ino same, size grew, and has lastCompleteLineOffset', () => {
    const cached = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
      lastCompleteLineOffset: 4500,
    })
    const current: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 2000, sizeBytes: 8000 }
    const result = reconcileFile(current, cached)
    expect(result).toEqual({ action: 'appended', readFromOffset: 4500 })
  })

  it('returns "modified" when ino changed', () => {
    const cached = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
    })
    const current: FileFingerprint = { dev: 1, ino: 200, mtimeMs: 2000, sizeBytes: 5000 }
    expect(reconcileFile(current, cached)).toEqual({ action: 'modified' })
  })

  it('a failed marker at the same fingerprint stays "unchanged" (not re-parsed)', () => {
    const fp: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 }
    const marker = makeCachedFile({ fingerprint: { ...fp }, turns: [], failed: true })
    expect(reconcileFile(fp, marker)).toEqual({ action: 'unchanged' })
  })

  it('a failed marker is re-parsed once the file changes', () => {
    const marker = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
      turns: [],
      failed: true,
    })
    const changed: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 2000, sizeBytes: 6000 }
    expect(reconcileFile(changed, marker)).toEqual({ action: 'modified' })
  })

  it('returns "modified" when the cached offset is stranded beyond the current EOF', () => {
    // A truncate-then-regrow can leave the resume offset past live bytes; resuming
    // there would drop the appended tail, so it must fall back to a full re-parse.
    const cached = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
      lastCompleteLineOffset: 9_000_000,
    })
    const current: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 2000, sizeBytes: 8000 }
    expect(reconcileFile(current, cached)).toEqual({ action: 'modified' })
  })

  it('returns "modified" when size shrank', () => {
    const cached = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
      lastCompleteLineOffset: 4500,
    })
    const current: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 2000, sizeBytes: 3000 }
    expect(reconcileFile(current, cached)).toEqual({ action: 'modified' })
  })

  it('returns "modified" when same size but different mtime', () => {
    const cached = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
    })
    const current: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 2000, sizeBytes: 5000 }
    expect(reconcileFile(current, cached)).toEqual({ action: 'modified' })
  })

  it('returns "modified" for DB provider (no lastCompleteLineOffset) on any fingerprint change', () => {
    const cached = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
    })
    const current: FileFingerprint = { dev: 1, ino: 100, mtimeMs: 2000, sizeBytes: 8000 }
    expect(reconcileFile(current, cached)).toEqual({ action: 'modified' })
  })

  it('returns "modified" when dev changed even if ino same and size grew', () => {
    const cached = makeCachedFile({
      fingerprint: { dev: 1, ino: 100, mtimeMs: 1000, sizeBytes: 5000 },
      lastCompleteLineOffset: 4500,
    })
    const current: FileFingerprint = { dev: 2, ino: 100, mtimeMs: 2000, sizeBytes: 8000 }
    expect(reconcileFile(current, cached)).toEqual({ action: 'modified' })
  })
})

// ── mergeCallByDedupKey ────────────────────────────────────────────────

describe('mergeCallByDedupKey', () => {
  it('keeps earlier timestamp', () => {
    const existing = makeCall({ timestamp: '2026-05-15T10:00:00Z' })
    const incoming = makeCall({ timestamp: '2026-05-15T10:01:00Z' })
    const merged = mergeCallByDedupKey(existing, incoming)
    expect(merged.timestamp).toBe('2026-05-15T10:00:00Z')
  })

  it('takes incoming usage (latest wins)', () => {
    const existing = makeCall({ usage: { ...makeCall().usage, outputTokens: 100 } })
    const incoming = makeCall({ usage: { ...makeCall().usage, outputTokens: 999 } })
    const merged = mergeCallByDedupKey(existing, incoming)
    expect(merged.usage.outputTokens).toBe(999)
  })

  it('takes incoming tools (latest wins)', () => {
    const existing = makeCall({ tools: ['Read'] })
    const incoming = makeCall({ tools: ['Read', 'Edit', 'Bash'] })
    const merged = mergeCallByDedupKey(existing, incoming)
    expect(merged.tools).toEqual(['Read', 'Edit', 'Bash'])
  })
})

// ── deep validation (loadCache) ────────────────────────────────────────

describe('loadCache validation', () => {
  async function writeRawCache(data: unknown): Promise<void> {
    await mkdir(TMP_DIR, { recursive: true })
    await writeFile(join(TMP_DIR, 'session-cache.json'), JSON.stringify(data))
  }

  it('rejects providers as array', async () => {
    await writeRawCache({ version: CACHE_VERSION, providers: [] })
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects provider section missing envFingerprint', async () => {
    await writeRawCache({ version: CACHE_VERSION, providers: { claude: { files: {} } } })
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects provider section with files as array', async () => {
    await writeRawCache({ version: CACHE_VERSION, providers: { claude: { envFingerprint: 'x', files: [] } } })
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects file with invalid fingerprint (missing ino)', async () => {
    await writeRawCache({
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, mtimeMs: 1, sizeBytes: 1 }, mcpInventory: [], turns: [] },
      } } },
    })
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects file with non-numeric fingerprint field', async () => {
    await writeRawCache({
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, ino: 'bad', mtimeMs: 1, sizeBytes: 1 }, mcpInventory: [], turns: [] },
      } } },
    })
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects turn with missing sessionId', async () => {
    const badTurn = { timestamp: 'x', userMessage: 'y', calls: [] }
    await writeRawCache({
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, ino: 2, mtimeMs: 3, sizeBytes: 4 }, mcpInventory: [], turns: [badTurn] },
      } } },
    })
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects call with missing usage object', async () => {
    const badCall = { provider: 'claude', model: 'm', deduplicationKey: 'k', timestamp: 't', tools: [], bashCommands: [], skills: [] }
    const turn = { timestamp: 'x', sessionId: 's', userMessage: 'y', calls: [badCall] }
    await writeRawCache({
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, ino: 2, mtimeMs: 3, sizeBytes: 4 }, mcpInventory: [], turns: [turn] },
      } } },
    })
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects call with NaN in usage', async () => {
    const badUsage = { inputTokens: NaN, outputTokens: 0, cacheCreationInputTokens: 0, cacheReadInputTokens: 0, cachedInputTokens: 0, reasoningTokens: 0, webSearchRequests: 0, cacheCreationOneHourTokens: 0 }
    const call = { provider: 'claude', model: 'm', usage: badUsage, deduplicationKey: 'k', timestamp: 't', tools: [], bashCommands: [], skills: [], speed: 'standard' }
    const turn = { timestamp: 'x', sessionId: 's', userMessage: 'y', calls: [call] }
    await writeRawCache({
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, ino: 2, mtimeMs: 3, sizeBytes: 4 }, mcpInventory: [], turns: [turn] },
      } } },
    })
    expect((await loadCache()).providers).toEqual({})
  })

  function validCallJson() {
    return {
      provider: 'claude', model: 'm', deduplicationKey: 'k', timestamp: 't', speed: 'standard',
      tools: ['Read'], bashCommands: ['ls'], skills: [],
      usage: { inputTokens: 1, outputTokens: 1, cacheCreationInputTokens: 0, cacheReadInputTokens: 0, cachedInputTokens: 0, reasoningTokens: 0, webSearchRequests: 0, cacheCreationOneHourTokens: 0 },
    }
  }

  function wrapCall(callOverride: Record<string, unknown>) {
    return {
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, ino: 2, mtimeMs: 3, sizeBytes: 4 }, mcpInventory: [], turns: [
          { timestamp: 'x', sessionId: 's', userMessage: 'y', calls: [{ ...validCallJson(), ...callOverride }] },
        ] },
      } } },
    }
  }

  function wrapFile(fileOverride: Record<string, unknown>) {
    return {
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, ino: 2, mtimeMs: 3, sizeBytes: 4 }, mcpInventory: [], turns: [], ...fileOverride },
      } } },
    }
  }

  it('rejects tools containing non-string element', async () => {
    await writeRawCache(wrapCall({ tools: ['Read', 42] }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects bashCommands containing object element', async () => {
    await writeRawCache(wrapCall({ bashCommands: [{}] }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects skills containing null element', async () => {
    await writeRawCache(wrapCall({ skills: [null] }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects invalid speed value', async () => {
    await writeRawCache(wrapCall({ speed: 'turbo' }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects non-string project', async () => {
    await writeRawCache(wrapCall({ project: 123 }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects non-string projectPath', async () => {
    await writeRawCache(wrapCall({ projectPath: true }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects mcpInventory containing non-string element', async () => {
    await writeRawCache(wrapFile({ mcpInventory: ['valid', 99] }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects non-numeric lastCompleteLineOffset', async () => {
    await writeRawCache(wrapFile({ lastCompleteLineOffset: 'bad' }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects NaN lastCompleteLineOffset', async () => {
    await writeRawCache(wrapFile({ lastCompleteLineOffset: null }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('rejects non-string canonicalCwd', async () => {
    await writeRawCache(wrapFile({ canonicalCwd: 42 }))
    expect((await loadCache()).providers).toEqual({})
  })

  it('accepts optional fields when absent', async () => {
    const cache: SessionCache = {
      version: CACHE_VERSION,
      providers: { claude: { envFingerprint: 'x', files: {
        '/f': { fingerprint: { dev: 1, ino: 2, mtimeMs: 3, sizeBytes: 4 }, mcpInventory: [], turns: [] },
      } } },
    }
    await writeRawCache(cache)
    expect(await loadCache()).toEqual(cache)
  })

  it('accepts a fully valid cache with all fields populated', async () => {
    const cache: SessionCache = {
      version: CACHE_VERSION,
      providers: {
        claude: {
          envFingerprint: 'abc',
          files: { '/f': makeCachedFile() },
        },
      },
    }
    await writeRawCache(cache)
    const loaded = await loadCache()
    expect(loaded).toEqual(cache)
  })
})

// ── cleanupOrphanedTempFiles ───────────────────────────────────────────

describe('cleanupOrphanedTempFiles', () => {
  it('removes .tmp files older than 5 minutes', async () => {
    await mkdir(TMP_DIR, { recursive: true })

    await mkdir(join(TMP_DIR, CACHE_DIR()), { recursive: true })
    const oldTmp = join(TMP_DIR, CACHE_DIR(), 'claude.abc123.json.tmp')
    await writeFile(oldTmp, 'stale')
    const { utimes } = await import('fs/promises')
    const oldTime = new Date(Date.now() - 10 * 60 * 1000)
    await utimes(oldTmp, oldTime, oldTime)

    await cleanupOrphanedTempFiles()
    expect(existsSync(oldTmp)).toBe(false)
  })

  it('preserves recent .tmp files', async () => {
    await mkdir(TMP_DIR, { recursive: true })

    await mkdir(join(TMP_DIR, CACHE_DIR()), { recursive: true })
    const recentTmp = join(TMP_DIR, CACHE_DIR(), 'claude.def456.json.tmp')
    await writeFile(recentTmp, 'recent')

    await cleanupOrphanedTempFiles()
    expect(existsSync(recentTmp)).toBe(true)
  })

  it('ignores .tmp files from other caches', async () => {
    await mkdir(TMP_DIR, { recursive: true })

    const otherTmp = join(TMP_DIR, 'codex-results.json.abc123.tmp')
    await writeFile(otherTmp, 'other cache temp')
    const { utimes } = await import('fs/promises')
    const oldTime = new Date(Date.now() - 10 * 60 * 1000)
    await utimes(otherTmp, oldTime, oldTime)

    await cleanupOrphanedTempFiles()
    expect(existsSync(otherTmp)).toBe(true)
  })

  it('does not fail when cache dir does not exist', async () => {
    process.env['CODEBURN_CACHE_DIR'] = '/no/such/dir'
    await cleanupOrphanedTempFiles()
  })
})

// ── loadCache memo (serve fast-path) ─────────────────────────────────────

describe('loadCache memo', () => {
  it('returns the identical object while the file is unchanged, reloads on rewrite', async () => {
    clearLoadCacheMemo()
    const cache = emptyCache()
    cache.providers['memo-test'] = { envFingerprint: 'x', files: {} }
    await saveCache(cache)

    // saveCache write-through: the very object just published is served back.
    const first = await loadCache()
    expect(first).toBe(cache)
    const second = await loadCache()
    expect(second).toBe(first)

    // An external rewrite (another process) moves mtime/size: fresh parse.
    const external = emptyCache()
    external.providers['memo-test-2'] = { envFingerprint: 'y', files: {} }
    await saveCache(external)
    const third = await loadCache()
    expect(third).toBe(external)
    expect(third).not.toBe(first)
    clearLoadCacheMemo()
  })
})