import { describe, expect, it } from 'vitest'
import {
  decideMigrationParityGate,
  migrationKey,
  migrationKeysOf,
} from '../migration-parity-gate.js'
// Repo-side drift lock: gitflow duplicates this logic on purpose (it must not
// import another skill at runtime), so the test — which DOES run from the repo,
// where both skills are present — asserts the two implementations agree.
import {
  findMissingReferenceMigrations,
  migrationKey as efcoreMigrationKey,
} from '../../../../efcore/cli/lib/squash-integrity.js'

const DIR = 'src/App.Infrastructure/Persistence/Migrations'
const mig = (name: string) => `${DIR}/${name}.cs`
const designer = (name: string) => `${DIR}/${name}.Designer.cs`
const SNAPSHOT = `${DIR}/ExtensionsDbContextModelSnapshot.cs`

const HOTFIX = 'Ext_v5.10.1_001_FixTaxRate'
const R1 = 'Ext_v5.10.0_001_AddOrders'
const R2 = 'Ext_v5.11.0_001_AddInvoices'

describe('migrationKey', () => {
  it('collapses a migration and its Designer sidecar to one key', () => {
    expect(migrationKey(mig(R1))).toBe(R1)
    expect(migrationKey(designer(R1))).toBe(R1)
  })

  it('is null for the snapshot and for non-.cs files', () => {
    expect(migrationKey(SNAPSHOT)).toBeNull()
    expect(migrationKey(`${DIR}/README.md`)).toBeNull()
  })

  it('normalises Windows separators', () => {
    expect(migrationKey(`src\\App\\Migrations\\${R1}.cs`)).toBe(R1)
  })
})

describe('migrationKeysOf', () => {
  it('keeps only .cs files living under a Migrations/ folder', () => {
    const keys = migrationKeysOf([
      mig(R1),
      designer(R1),
      SNAPSHOT,
      'src/App.Domain/Entities/Order.cs', // real .cs, but not a migration
      'src/App.Api/Migrations.md',
    ])
    expect(keys).toEqual([R1])
  })

  it('matches the singular Migration/ folder variant and a repo-root folder', () => {
    expect(migrationKeysOf([`src/Infra/Migration/${R1}.cs`])).toEqual([R1])
    expect(migrationKeysOf([`Migrations/${R1}.cs`])).toEqual([R1])
  })

  it('de-duplicates and sorts', () => {
    expect(migrationKeysOf([mig(R2), designer(R2), mig(R1)])).toEqual([R1, R2])
  })
})

describe('decideMigrationParityGate — the release→main prod-regression gate', () => {
  it('BLOCKS when a hotfix migration on main is absent from the release branch', () => {
    const reference = [mig(R1), designer(R1), mig(HOTFIX), designer(HOTFIX), SNAPSHOT]
    const head = [mig(R1), designer(R1), mig(R2), designer(R2), SNAPSHOT]

    const gate = decideMigrationParityGate(reference, head, 'main')

    expect(gate.ok).toBe(false)
    expect(gate.missing).toEqual([HOTFIX])
    expect(gate.preserved).toBe(1)
    expect(gate.error).toContain(HOTFIX)
    expect(gate.error).toContain('ModelSnapshot.cs')
    // The remediation must be actionable, and the escape hatch discoverable.
    expect(gate.error).toContain('/gitflow update')
    expect(gate.error).toContain('confirmRebaseline')
  })

  it('PASSES the nominal release — main’s migrations all present, plus new ones', () => {
    const reference = [mig(R1), designer(R1), SNAPSHOT]
    const head = [mig(R1), designer(R1), mig(R2), designer(R2), SNAPSHOT]

    const gate = decideMigrationParityGate(reference, head, 'main')

    expect(gate.ok).toBe(true)
    expect(gate.missing).toEqual([])
    expect(gate.preserved).toBe(1)
    expect(gate.warnings).toEqual([])
  })

  it('PASSES when a reference migration merely MOVED to another folder', () => {
    const reference = [mig(R1), SNAPSHOT]
    const head = [`src/App.Infrastructure/Migrations/Extensions/${R1}.cs`, SNAPSHOT]

    expect(decideMigrationParityGate(reference, head, 'main').ok).toBe(true)
  })

  it('PASSES when only the Designer sidecar of a reference migration survives', () => {
    // The pair collapses to one key — an asymmetric sidecar is not a prod loss.
    const gate = decideMigrationParityGate([mig(R1), designer(R1)], [designer(R1)], 'main')
    expect(gate.ok).toBe(true)
  })

  it('is INERT for a repo holding no migrations at all', () => {
    const gate = decideMigrationParityGate(
      ['src/index.ts', 'package.json'],
      ['src/index.ts'],
      'main',
    )
    expect(gate).toEqual({ ok: true, warnings: [], missing: [], preserved: 0 })
  })

  it('does not treat a dropped ModelSnapshot as a missing migration', () => {
    const gate = decideMigrationParityGate([mig(R1), SNAPSHOT], [mig(R1)], 'main')
    expect(gate.ok).toBe(true)
    expect(gate.missing).toEqual([])
  })

  it('confirmRebaseline downgrades the block to a LOUD warning, never silence', () => {
    const gate = decideMigrationParityGate([mig(R1), mig(HOTFIX)], [mig(R1)], 'main', true)

    expect(gate.ok).toBe(true)
    expect(gate.missing).toEqual([HOTFIX])
    expect(gate.error).toBeUndefined()
    expect(gate.warnings).toHaveLength(1)
    expect(gate.warnings[0]).toContain(HOTFIX)
    expect(gate.warnings[0]).toContain('re-baselined')
  })

  it('reports EVERY missing migration, sorted', () => {
    const gate = decideMigrationParityGate([mig(R2), mig(R1), mig(HOTFIX)], [], 'main')
    expect(gate.missing).toEqual([R1, HOTFIX, R2].sort())
    expect(gate.error).toContain('3 migration(s)')
  })

  it('names the target branch it protected', () => {
    const gate = decideMigrationParityGate([mig(R1)], [], 'production')
    expect(gate.error).toContain("'production'")
  })
})

describe('drift lock vs efcore/cli/lib/squash-integrity.ts', () => {
  const CORPUS = [
    mig(R1),
    designer(R1),
    SNAPSHOT,
    `${DIR}/20260101120000_${R2}.cs`,
    `src\\App\\Migrations\\${HOTFIX}.Designer.cs`,
    `${DIR}/README.md`,
    'src/App.Domain/Entities/Order.cs',
  ]

  it('migrationKey agrees with the efcore SSOT on every corpus path', () => {
    for (const p of CORPUS) {
      expect(migrationKey(p), p).toEqual(efcoreMigrationKey(p))
    }
  })

  it('the gate flags exactly what findMissingReferenceMigrations flags', () => {
    const reference = [mig(R1), designer(R1), mig(HOTFIX), SNAPSHOT]
    const head = [mig(R1), designer(R1), SNAPSHOT]

    expect(decideMigrationParityGate(reference, head, 'main').missing).toEqual(
      findMissingReferenceMigrations(reference, head),
    )
  })
})