#Requires -Modules @{ ModuleName = 'Pester'; ModuleVersion = '5.0.0' }

<#
    FR-021, SC-007: Processed = Matched + Unclassified + EvaluationError at every
    summary, and a mismatch is reported as an engine defect.

    The forced-mismatch tests are the point. A reconciliation check that only ever
    sees correct data proves that the arithmetic works, not that the failure path
    does - and the failure path is the only part anyone will ever depend on.
#>

BeforeAll {
    $repoRoot = Split-Path (Split-Path $PSScriptRoot -Parent) -Parent
    . (Join-Path $repoRoot 'tests/TestHelpers.ps1')
    foreach ($file in (Get-PersonaSourceFile -RepoRoot $repoRoot)) { . $file }

    $script:target = 'extension_<EXTENSION-APP-ID>_<PERSONA>'
    $script:population = @(New-TestPopulation -Count 15 -TargetAttribute $target)
}

Describe 'Reconciliation arithmetic (FR-021)' {

    It 'passes when the outcome buckets account for every processed user' {
        $counters = New-PersonaRunCounter -Rules @()
        $counters.Processed = 10
        $counters.Matched = 7
        $counters.Unclassified = 2
        $counters.EvaluationError = 1

        Test-PersonaReconciliation -Counters $counters | Should -BeTrue
    }

    It 'fails when a user was processed but landed in no bucket' {
        $counters = New-PersonaRunCounter -Rules @()
        $counters.Processed = 10
        $counters.Matched = 7
        $counters.Unclassified = 2
        $counters.EvaluationError = 0

        Test-PersonaReconciliation -Counters $counters | Should -BeFalse
    }

    It 'fails when a user was double-counted' {
        $counters = New-PersonaRunCounter -Rules @()
        $counters.Processed = 10
        $counters.Matched = 8
        $counters.Unclassified = 2
        $counters.EvaluationError = 1

        Test-PersonaReconciliation -Counters $counters | Should -BeFalse
    }

    It 'passes trivially on an empty run' {
        Test-PersonaReconciliation -Counters (New-PersonaRunCounter -Rules @()) | Should -BeTrue
    }

    It 'ignores the action buckets, which would otherwise mask a lost user' {
        # Skipped is a catch-all. If reconciliation checked the action buckets, a lost
        # user absorbed into Skipped would keep the sums balanced on a broken run.
        $counters = New-PersonaRunCounter -Rules @()
        $counters.Processed = 5
        $counters.Matched = 5
        $counters.Skipped = 99

        Test-PersonaReconciliation -Counters $counters | Should -BeTrue
    }
}

Describe 'Reconciliation failure detail' {

    It 'reports the difference and its sign so a maintainer can tell loss from duplication' {
        $counters = New-PersonaRunCounter -Rules @()
        $counters.Processed = 10
        $counters.Matched = 7
        $counters.Unclassified = 2
        $counters.EvaluationError = 0

        $detail = Get-PersonaReconciliationDetail -Counters $counters

        $detail.processed | Should -Be 10
        $detail.outcomeTotal | Should -Be 9
        $detail.difference | Should -Be 1
        $detail.severity | Should -Be 'Error'
        $detail.defect | Should -Be 'ReconciliationFailure'
    }

    It 'reports a negative difference when a user was double-counted' {
        $counters = New-PersonaRunCounter -Rules @()
        $counters.Processed = 10
        $counters.Matched = 9
        $counters.Unclassified = 2

        (Get-PersonaReconciliationDetail -Counters $counters).difference | Should -Be -1
    }
}

Describe 'Reconciliation over a real run (SC-007)' {

    BeforeEach {
        Mock Get-PersonaUsers { $script:population }
        Mock Write-Host { }
    }

    It 'reconciles at every interim summary and at completion' {
        $config = New-TestRuntimeConfiguration -TargetAttribute $target -SummaryInterval 5

        $info = $null
        $null = Invoke-PersonaEngineRun -Configuration $config -TargetAttribute $target `
            -Context (New-TestAuditContext) -AuditParameters @{ Destination = 'stream' } `
            -InformationVariable info

        $summaries = Get-CapturedAuditRecord -Captured $info -RecordType 'Summary'

        # Three interim boundaries at 5, 10, 15 plus the final summary.
        $summaries.Count | Should -BeGreaterThan 1
        foreach ($summary in $summaries) {
            $summary['reconciliationPassed'] | Should -BeTrue
            $summary['processed'] | Should -Be ($summary['matched'] + $summary['unclassified'] + $summary['evaluationError'])
        }
    }

    It 'returns exit code 5 and emits an EngineDefect when reconciliation fails' {
        # The failure is forced by making Add-PersonaRunResult drop the outcome tally
        # while still counting the user as processed - precisely the bookkeeping defect
        # FR-021 exists to catch.
        Mock Add-PersonaRunResult { $Counters.Processed++ }

        $config = New-TestRuntimeConfiguration -TargetAttribute $target -SummaryInterval 0

        $info = $null
        $outcome = Invoke-PersonaEngineRun -Configuration $config -TargetAttribute $target `
            -Context (New-TestAuditContext) -AuditParameters @{ Destination = 'stream' } `
            -InformationVariable info

        $outcome.ExitCode | Should -Be 5

        $defects = Get-CapturedAuditRecord -Captured $info -RecordType 'EngineDefect'

        $defects.Count | Should -BeGreaterThan 0
        $defects[0]['defect'] | Should -Be 'ReconciliationFailure'
        $defects[0]['severity'] | Should -Be 'Error'
    }

    It 'marks the summary record itself as failed when reconciliation fails' {
        Mock Add-PersonaRunResult { $Counters.Processed++ }

        $config = New-TestRuntimeConfiguration -TargetAttribute $target -SummaryInterval 0

        $info = $null
        $null = Invoke-PersonaEngineRun -Configuration $config -TargetAttribute $target `
            -Context (New-TestAuditContext) -AuditParameters @{ Destination = 'stream' } `
            -InformationVariable info

        (Get-CapturedAuditRecord -Captured $info -RecordType 'Summary')[0]['reconciliationPassed'] | Should -BeFalse
    }
}