import { describe, it, expect, vi, beforeEach } from 'vitest'
import fc from 'fast-check'
import ConfigurationEngine from '../../app/services/configuration_engine.js'
import type { Configuration, ConfigurationCriteria } from '../../app/domain/configuration/configuration.js'
import { PolicyType } from '../../app/domain/configuration/configuration.js'
import type { Device } from '../../app/domain/device/device.js'
import type { DeviceId } from '../../app/domain/device/device_id.js'
import { buildProvisioningCode } from '../../app/utils/provisioning_code.js'

// Mock the models and services
vi.mock('#models/configuration', () => {
  return {
    default: {
      find: vi.fn(),
      findOne: vi.fn(),
    },
  }
})

vi.mock('#models/device', () => {
  return {
    default: {
      findOne: vi.fn(),
    },
  }
})

vi.mock('../../app/services/firmware_catalog_service.js', () => {
  return {
    default: class FirmwareCatalogService {
      async resolveUpgradePath() {
        return []
      }
    },
  }
})

import ConfigurationModel from '#models/configuration'
import DeviceModel from '#models/device'

/**
 * Property 6: Highest priority Configuration wins
 * Validates: Requirements 3.2
 *
 * Property: When multiple configurations match a device, the one with highest
 * priority is selected. If no configurations match, result is compliant.
 */
describe('Property 6: Highest priority Configuration wins', () => {
  let engine: ConfigurationEngine

  beforeEach(() => {
    engine = new ConfigurationEngine()
    vi.clearAllMocks()
  })

  // Arbitrary to generate positive priority integers
  const priority = fc.integer({ min: 1, max: 1000 })

  // Arbitrary to generate a valid device
  function deviceArb(): fc.Arbitrary<Device> {
    return fc.record({
      deviceId: fc.record({
        id: fc.uuid(),
        manufacturer: fc.string(),
        oui: fc.string(),
        productClass: fc.string(),
        serialNumber: fc.string(),
      }) as unknown as fc.Arbitrary<DeviceId>,
      createdAt: fc.date(),
    }) as unknown as fc.Arbitrary<Device>
  }

  // Arbitrary to generate a valid configuration
  function configurationArb(overrides?: Partial<Configuration>): fc.Arbitrary<Configuration> {
    const baseArb = fc.record({
      identifier: fc.string().filter((s) => s.length > 0),
      name: fc.string(),
      version: fc.stringMatching(/\d+\.\d+\.\d+/),
      priority: priority,
      policy: fc.constantFrom(PolicyType.ONCE, PolicyType.MAINTAIN),
      enabled: fc.constant(true),
      tags: fc.array(fc.string()),
      criteria: fc.record({
        manufacturer: fc.option(fc.string(), { nil: undefined }),
        oui: fc.option(fc.string(), { nil: undefined }),
        productClass: fc.option(fc.string(), { nil: undefined }),
        serialNumber: fc.option(fc.string(), { nil: undefined }),
      }) as fc.Arbitrary<ConfigurationCriteria>,
      inventory: fc.array(
        fc.record({
          path: fc.string(),
        })
      ) as fc.Arbitrary<any>,
      desiredParameters: fc.array(
        fc.record({
          name: fc.string(),
          value: fc.oneof(fc.string(), fc.integer(), fc.boolean()),
          type: fc.constantFrom('string', 'int', 'boolean'),
        })
      ) as fc.Arbitrary<any>,
      firmwareTarget: fc.option(
        fc.record({
          productClass: fc.string(),
          targetVersion: fc.stringMatching(/\d+\.\d+\.\d+/),
        }),
        { nil: undefined }
      ) as fc.Arbitrary<any>,
      schedule: fc.constant(undefined) as fc.Arbitrary<any>,
      createdAt: fc.date() as fc.Arbitrary<any>,
      updatedAt: fc.date() as fc.Arbitrary<any>,
    })

    if (overrides) {
      return baseArb.map((val) => ({
        ...val,
        ...overrides,
      })) as fc.Arbitrary<Configuration>
    }

    return baseArb as fc.Arbitrary<Configuration>
  }

  it('selects configuration with highest priority when multiple match', async () => {
    await fc.assert(
      fc.asyncProperty(deviceArb(), async (device) => {
        // Generate configurations with arbitrary priorities
        const numConfigs = fc.sample(fc.integer({ min: 2, max: 5 }), 1)[0]
        const configsArray = fc.sample(configurationArb(), numConfigs)

        // Ensure all have matching criteria (empty)
        const configurations = configsArray.map((c) => ({
          ...c,
          criteria: {} as ConfigurationCriteria,
        }))

        vi.mocked(ConfigurationModel.find).mockResolvedValue(configurations as any)
        vi.mocked(DeviceModel.findOne).mockResolvedValue(device as any)

        const result = await engine.evaluate(device)

        // Find expected highest priority config
        const highest = configurations.reduce((max, c) =>
          c.priority > max.priority ? c : max
        )

        expect(result.configuration?.priority).toBe(highest.priority)
        expect(result.configuration?.identifier).toBe(highest.identifier)
      })
    )
  })

  it('returns compliant result when no configurations match', async () => {
    await fc.assert(
      fc.asyncProperty(deviceArb(), async (device) => {
        vi.mocked(ConfigurationModel.find).mockResolvedValue([])

        const result = await engine.evaluate(device)

        expect(result.configuration).toBeNull()
        expect(result.isAlreadyCompliant).toBe(true)
        expect(result.parameterDiffs).toEqual([])
        expect(result.firmwareMigrationPath).toEqual([])
      })
    )
  })
})

/**
 * Property 8: Diff engine computes only differing parameters
 * Validates: Requirements 5.1, 5.2, 5.3, 6.5
 *
 * Property: The diff computation returns only parameters where currentValue !== targetValue.
 */
describe('Property 8: Diff engine computes only differing parameters', () => {
  let engine: ConfigurationEngine

  beforeEach(() => {
    engine = new ConfigurationEngine()
    vi.clearAllMocks()
  })

  it('returns empty diffs when all desired parameters match current values', async () => {
    await fc.assert(
      fc.asyncProperty(
        fc.array(
          fc.record({
            name: fc.string().filter((s) => s.length > 0),
            value: fc.oneof(fc.string(), fc.integer(), fc.boolean()),
            type: fc.constantFrom('string', 'int', 'boolean'),
          }),
          { minLength: 1, maxLength: 10 }
        ).map((params) => {
          // Deduplicate by name to avoid conflicting values for the same parameter
          const seen = new Set<string>()
          return params.filter((p) => {
            if (seen.has(p.name)) return false
            seen.add(p.name)
            return true
          })
        }).filter((params) => params.length > 0),
        async (desiredParams) => {
          const device = {
            deviceId: { id: 'test', manufacturer: 'Test' },
            createdAt: new Date(),
            getParameter: (name: string) => ({
              value: desiredParams.find((p) => p.name === name)?.value,
            }),
          } as any

          const config = {
            identifier: 'test',
            priority: 1,
            enabled: true,
            policy: PolicyType.MAINTAIN,
            criteria: {},
            inventory: [],
            desiredParameters: desiredParams,
            createdAt: new Date(),
            updatedAt: new Date(),
          } as any

          vi.mocked(ConfigurationModel.find).mockResolvedValue([config])
          vi.mocked(DeviceModel.findOne).mockResolvedValue(device)

          const result = await engine.evaluate(device)

          expect(result.parameterDiffs).toEqual([])
        }
      )
    )
  })

  it('returns diffs only for parameters that differ', async () => {
    const desiredParams = [
      { name: 'param1', value: 'value1', type: 'string' },
      { name: 'param2', value: 'value2', type: 'string' },
    ]

    const device = {
      deviceId: { id: 'test', manufacturer: 'Test' },
      createdAt: new Date(),
      getParameter: (name: string) => {
        if (name === 'param1') return { value: 'value1' } // Matches
        if (name === 'param2') return { value: 'different' } // Differs
        return { value: undefined }
      },
    } as any

    const config = {
      identifier: 'test',
      priority: 1,
      enabled: true,
      policy: PolicyType.MAINTAIN,
      criteria: {},
      inventory: [],
      desiredParameters: desiredParams,
      createdAt: new Date(),
      updatedAt: new Date(),
    } as any

    vi.mocked(ConfigurationModel.find).mockResolvedValue([config])

    const engine = new ConfigurationEngine()
    const result = await engine.evaluate(device)

    expect(result.parameterDiffs).toHaveLength(1)
    expect(result.parameterDiffs[0].name).toBe('param2')
    expect(result.parameterDiffs[0].currentValue).toBe('different')
    expect(result.parameterDiffs[0].targetValue).toBe('value2')
  })
})

/**
 * Property 10: Policy "once" applies based on content hash comparison
 * Validates: Requirements 6.1, 6.3
 *
 * Property: A configuration with policy "once" applies only if the device
 * doesn't have a matching provisioning code with the same content hash.
 */
describe('Property 10: Policy "once" applies based on content hash comparison', () => {
  let engine: ConfigurationEngine

  beforeEach(() => {
    engine = new ConfigurationEngine()
    vi.clearAllMocks()
  })

  it('applies "once" policy if device has no provisioning code', async () => {
    const config = {
      identifier: 'config1',
      priority: 1,
      enabled: true,
      policy: PolicyType.ONCE,
      criteria: {},
      inventory: [],
      desiredParameters: [{ name: 'param1', value: 'value1', type: 'string' }],
      createdAt: new Date(),
      updatedAt: new Date(),
    } as any

    const device = {
      deviceId: { id: 'test', manufacturer: 'Test' },
      createdAt: new Date(),
      getParameter: (name: string) => ({
        value: name === 'param1' ? 'different' : undefined,
      }),
      // No provisioningCode property
    } as any

    vi.mocked(ConfigurationModel.find).mockResolvedValue([config])

    const result = await engine.evaluate(device)

    expect(result.parameterDiffs).toHaveLength(1)
  })

  it('skips "once" policy if provisioning code matches content hash', async () => {
    const config = {
      identifier: 'config1',
      priority: 1,
      enabled: true,
      policy: PolicyType.ONCE,
      criteria: {},
      inventory: [],
      desiredParameters: [{ name: 'param1', value: 'value1', type: 'string' }],
      createdAt: new Date(),
      updatedAt: new Date(),
    } as any

    const provCode = buildProvisioningCode(config)

    const device = {
      deviceId: { id: 'test', manufacturer: 'Test' },
      createdAt: new Date(),
      getParameter: (name: string) => ({
        value: name === 'param1' ? 'value1' : undefined,
      }),
      provisioningCode: provCode,
    } as any

    vi.mocked(ConfigurationModel.find).mockResolvedValue([config])

    const result = await engine.evaluate(device)

    expect(result.isAlreadyCompliant).toBe(true)
    expect(result.parameterDiffs).toEqual([])
  })

  it('reapplies "once" policy if content hash changes', async () => {
    const configV1 = {
      identifier: 'config1',
      priority: 1,
      enabled: true,
      policy: PolicyType.ONCE,
      criteria: {},
      inventory: [],
      desiredParameters: [{ name: 'param1', value: 'value1', type: 'string' }],
      createdAt: new Date(),
      updatedAt: new Date(),
    } as any

    const provCodeV1 = buildProvisioningCode(configV1)

    // New config version with different content
    const configV2 = {
      ...configV1,
      desiredParameters: [{ name: 'param1', value: 'value2', type: 'string' }],
    } as any

    const device = {
      deviceId: { id: 'test', manufacturer: 'Test' },
      createdAt: new Date(),
      getParameter: (name: string) => ({
        value: name === 'param1' ? 'value1' : undefined,
      }),
      provisioningCode: provCodeV1, // Has old provisioning code
    } as any

    vi.mocked(ConfigurationModel.find).mockResolvedValue([configV2])

    const result = await engine.evaluate(device)

    // Should reapply because content hash changed
    expect(result.parameterDiffs).toHaveLength(1)
    expect(result.parameterDiffs[0].targetValue).toBe('value2')
  })
})

/**
 * Property 16: Dry-run is side-effect-free
 * Validates: Requirements 16.1, 16.2
 *
 * Property: Calling dryRun() should not modify the device or database state.
 */
describe('Property 16: Dry-run is side-effect-free', () => {
  let engine: ConfigurationEngine

  beforeEach(() => {
    engine = new ConfigurationEngine()
    vi.clearAllMocks()
  })

  it('dryRun returns EngineResult without modifying device', async () => {
    const config = {
      identifier: 'config1',
      priority: 1,
      enabled: true,
      policy: PolicyType.MAINTAIN,
      criteria: {},
      inventory: [],
      desiredParameters: [{ name: 'param1', value: 'value1', type: 'string' }],
      createdAt: new Date(),
      updatedAt: new Date(),
    } as any

    const device = {
      deviceId: { id: 'test', manufacturer: 'Test' },
      createdAt: new Date(),
      getParameter: (name: string) => ({
        value: name === 'param1' ? 'different' : undefined,
      }),
    } as any

    // Make a deep copy to check it hasn't changed
    const deviceSnapshot = JSON.parse(JSON.stringify(device))

    vi.mocked(ConfigurationModel.findOne).mockResolvedValue(config)
    vi.mocked(DeviceModel.findOne).mockResolvedValue(device)

    const result = await engine.dryRun('config1', 'test')

    // Verify device snapshot hasn't changed
    expect(JSON.stringify(device)).toBe(JSON.stringify(deviceSnapshot))

    // Verify result is valid
    expect(result).toHaveProperty('configurationId', 'config1')
    expect(result).toHaveProperty('deviceIdentifier', 'test')
    expect(result.evaluation).toHaveProperty('parameterDiffs')
  })

  it('dryRun does not persist any changes', async () => {
    const config = {
      identifier: 'config1',
      priority: 1,
      enabled: true,
      policy: PolicyType.ONCE,
      criteria: {},
      inventory: [],
      desiredParameters: [{ name: 'param1', value: 'value1', type: 'string' }],
      createdAt: new Date(),
      updatedAt: new Date(),
    } as any

    const device = {
      deviceId: { id: 'test', manufacturer: 'Test' },
      createdAt: new Date(),
      getParameter: (name: string) => ({
        value: name === 'param1' ? 'different' : undefined,
      }),
    } as any

    vi.mocked(ConfigurationModel.findOne).mockResolvedValue(config)
    vi.mocked(DeviceModel.findOne).mockResolvedValue(device)

    const result = await engine.dryRun('config1', 'test')

    // Verify result is a DryRunResult with expected properties
    expect(result).toBeDefined()
    expect(result.configurationId).toBe('config1')
    expect(result.deviceIdentifier).toBe('test')
    
    // Verify no save/update calls were made (mocks should not have been called)
    // Since we're mocking, any DB mutations would show up in mock call counts
    expect(vi.mocked(ConfigurationModel.findOne)).toHaveBeenCalledTimes(1) // Only read call
    expect(vi.mocked(DeviceModel.findOne)).toHaveBeenCalledTimes(1) // Only read call

    // No mutation methods should have been called
    // (we didn't mock save/update, so they shouldn't exist on our mocked objects)
  })
})