param(
    [switch]$Refresh
)

$ErrorActionPreference = 'Stop'

$datasetRoot = Split-Path -Parent $PSScriptRoot
$sourceDir = Join-Path $datasetRoot 'source'
$dataDir = Join-Path $datasetRoot 'data'
$sourcePath = Join-Path $sourceDir 'fbi-cde-wa-mvt-2018-2025.json'
$monthlyPath = Join-Path $dataDir 'monthly.csv'
$annualPath = Join-Path $dataDir 'annual-summary.csv'
$periodDescriptivesPath = Join-Path $dataDir 'policy-period-descriptives.csv'
$manifestPath = Join-Path $datasetRoot 'release-manifest.json'
$endpoint = 'https://cde.ucr.cjis.gov/LATEST/summarized/state/WA/motor-vehicle-theft?from=01-2018&to=12-2025'

New-Item -ItemType Directory -Force -Path $sourceDir, $dataDir | Out-Null

if ($Refresh -or -not (Test-Path $sourcePath)) {
    $response = Invoke-WebRequest -UseBasicParsing -Uri $endpoint -TimeoutSec 60
    if ($response.StatusCode -ne 200) {
        throw "FBI CDE returned HTTP $($response.StatusCode)."
    }

    [System.IO.File]::WriteAllText(
        $sourcePath,
        $response.Content,
        (New-Object System.Text.UTF8Encoding($false))
    )
}

$sourceText = [System.IO.File]::ReadAllText($sourcePath)
$source = $sourceText | ConvertFrom-Json

$waOffenses = $source.offenses.actuals.'Washington Offenses'
$waClearances = $source.offenses.actuals.'Washington Clearances'
$waOffenseRates = $source.offenses.rates.'Washington Offenses'
$waClearanceRates = $source.offenses.rates.'Washington Clearances'
$usOffenses = $source.offenses.actuals.'United States Offenses'
$usClearances = $source.offenses.actuals.'United States Clearances'
$usOffenseRates = $source.offenses.rates.'United States Offenses'
$usClearanceRates = $source.offenses.rates.'United States Clearances'
$waPopulation = $source.populations.population.Washington
$usPopulation = $source.populations.population.'United States'
$waCoverage = $source.tooltips.'Percent of Population Coverage'.Washington
$usCoverage = $source.tooltips.'Percent of Population Coverage'.'United States'

$rows = foreach ($property in $waOffenses.PSObject.Properties) {
    $sourceMonth = $property.Name
    $month = [DateTime]::ParseExact(
        "01-$sourceMonth",
        'dd-MM-yyyy',
        [Globalization.CultureInfo]::InvariantCulture
    )

    [pscustomobject][ordered]@{
        month = $month.ToString('yyyy-MM-dd')
        wa_reported_offenses = [int]$property.Value
        wa_offense_rate_per_100k = [decimal]$waOffenseRates.$sourceMonth
        wa_clearances = [int]$waClearances.$sourceMonth
        wa_clearance_rate_per_100k = [decimal]$waClearanceRates.$sourceMonth
        wa_population = [long]$waPopulation.$sourceMonth
        wa_population_coverage_pct = [decimal]$waCoverage.$sourceMonth
        us_reported_offenses = [int]$usOffenses.$sourceMonth
        us_offense_rate_per_100k = [decimal]$usOffenseRates.$sourceMonth
        us_clearances = [int]$usClearances.$sourceMonth
        us_clearance_rate_per_100k = [decimal]$usClearanceRates.$sourceMonth
        us_population = [long]$usPopulation.$sourceMonth
        us_population_coverage_pct = [decimal]$usCoverage.$sourceMonth
    }
}

$rows = @($rows | Sort-Object month)

if ($rows.Count -ne 96) {
    throw "Expected 96 monthly rows but found $($rows.Count)."
}

$expectedMonths = for ($i = 0; $i -lt 96; $i++) {
    ([DateTime]'2018-01-01').AddMonths($i).ToString('yyyy-MM-dd')
}

for ($i = 0; $i -lt $expectedMonths.Count; $i++) {
    if ($rows[$i].month -ne $expectedMonths[$i]) {
        throw "Month validation failed at row $($i + 1): expected $($expectedMonths[$i]), found $($rows[$i].month)."
    }
}

$requiredNumericFields = @(
    'wa_reported_offenses',
    'wa_offense_rate_per_100k',
    'wa_clearances',
    'wa_clearance_rate_per_100k',
    'wa_population',
    'wa_population_coverage_pct',
    'us_reported_offenses',
    'us_offense_rate_per_100k',
    'us_clearances',
    'us_clearance_rate_per_100k',
    'us_population',
    'us_population_coverage_pct'
)

foreach ($row in $rows) {
    foreach ($field in $requiredNumericFields) {
        if ($null -eq $row.$field -or $row.$field -lt 0) {
            throw "Invalid $field for $($row.month)."
        }
    }

    if ($row.wa_population_coverage_pct -gt 100 -or $row.us_population_coverage_pct -gt 100) {
        throw "Population coverage exceeds 100% for $($row.month)."
    }
}

$rows | Export-Csv -NoTypeInformation -Encoding UTF8 -Path $monthlyPath

$previousWaTotal = $null
$annual = foreach ($group in ($rows | Group-Object { $_.month.Substring(0, 4) } | Sort-Object Name)) {
    $waTotal = [long]($group.Group | Measure-Object wa_reported_offenses -Sum).Sum
    $usTotal = [long]($group.Group | Measure-Object us_reported_offenses -Sum).Sum

    $change = if ($null -eq $previousWaTotal) {
        $null
    }
    else {
        [Math]::Round((($waTotal - $previousWaTotal) / $previousWaTotal) * 100, 2)
    }

    $annualRow = [pscustomobject][ordered]@{
        year = [int]$group.Name
        months = $group.Count
        wa_reported_offenses = $waTotal
        wa_year_over_year_change_pct = $change
        wa_clearances = [long]($group.Group | Measure-Object wa_clearances -Sum).Sum
        wa_min_population_coverage_pct = [decimal]($group.Group | Measure-Object wa_population_coverage_pct -Minimum).Minimum
        wa_max_population_coverage_pct = [decimal]($group.Group | Measure-Object wa_population_coverage_pct -Maximum).Maximum
        us_reported_offenses = $usTotal
        us_min_population_coverage_pct = [decimal]($group.Group | Measure-Object us_population_coverage_pct -Minimum).Minimum
        us_max_population_coverage_pct = [decimal]($group.Group | Measure-Object us_population_coverage_pct -Maximum).Maximum
    }

    $previousWaTotal = $waTotal
    $annualRow
}

$annual | Export-Csv -NoTypeInformation -Encoding UTF8 -Path $annualPath

$analysisPeriods = @(
    [ordered]@{
        period = 'pre_hb1054'
        start = [DateTime]'2018-01-01'
        end = [DateTime]'2021-06-01'
    },
    [ordered]@{
        period = 'hb1054_full_months'
        start = [DateTime]'2021-08-01'
        end = [DateTime]'2023-04-01'
    },
    [ordered]@{
        period = 'sb5352_full_months'
        start = [DateTime]'2023-06-01'
        end = [DateTime]'2024-05-01'
    },
    [ordered]@{
        period = 'i2113_full_months'
        start = [DateTime]'2024-07-01'
        end = [DateTime]'2025-12-01'
    }
)

$periodDescriptives = foreach ($period in $analysisPeriods) {
    $periodRows = @(
        $rows | Where-Object {
            ([DateTime]$_.month) -ge $period.start -and
            ([DateTime]$_.month) -le $period.end
        }
    )

    $rateRatios = @(
        $periodRows | ForEach-Object {
            $_.wa_offense_rate_per_100k / $_.us_offense_rate_per_100k
        }
    )

    [pscustomobject][ordered]@{
        period = $period.period
        start_month = $period.start.ToString('yyyy-MM-dd')
        end_month = $period.end.ToString('yyyy-MM-dd')
        months = $periodRows.Count
        mean_monthly_wa_offenses = [Math]::Round(
            ($periodRows | Measure-Object wa_reported_offenses -Average).Average,
            1
        )
        mean_wa_rate_per_100k = [Math]::Round(
            ($periodRows | Measure-Object wa_offense_rate_per_100k -Average).Average,
            2
        )
        mean_us_rate_per_100k = [Math]::Round(
            ($periodRows | Measure-Object us_offense_rate_per_100k -Average).Average,
            2
        )
        mean_wa_to_us_rate_ratio = [Math]::Round(
            ($rateRatios | Measure-Object -Average).Average,
            2
        )
        minimum_wa_population_coverage_pct = [decimal](
            $periodRows |
                Measure-Object wa_population_coverage_pct -Minimum
        ).Minimum
        causal_interpretation_permitted = $false
    }
}

$periodDescriptives |
    Export-Csv -NoTypeInformation -Encoding UTF8 -Path $periodDescriptivesPath

$artifactPaths = @(
    $sourcePath,
    $monthlyPath,
    $annualPath,
    $periodDescriptivesPath,
    (Join-Path $dataDir 'policy-periods.csv'),
    (Join-Path $datasetRoot 'quality-report.md'),
    (Join-Path $datasetRoot 'source-audit.md'),
    (Join-Path $datasetRoot 'data-request-template.md')
)

$artifacts = foreach ($path in $artifactPaths) {
    if (-not (Test-Path $path)) {
        throw "Required artifact is missing: $path"
    }

    $item = Get-Item $path
    [ordered]@{
        path = $item.FullName.Substring($datasetRoot.Length + 1).Replace('\', '/')
        bytes = $item.Length
        sha256 = (Get-FileHash -Algorithm SHA256 -Path $path).Hash.ToLowerInvariant()
    }
}

$manifest = [ordered]@{
    datasetKey = 'washington-monthly-motor-vehicle-theft-2018-2025'
    release = '0.1'
    status = 'research'
    generatedAtUtc = [DateTime]::UtcNow.ToString('o')
    coverage = [ordered]@{
        start = $rows[0].month
        end = $rows[-1].month
        months = $rows.Count
    }
    principalSource = [ordered]@{
        publisher = 'Federal Bureau of Investigation'
        system = 'Crime Data Explorer'
        endpoint = $endpoint
        sourceMaxDataDate = $source.cde_properties.max_data_date.UCR
        sourceLastRefreshDate = $source.cde_properties.last_refresh_date.UCR
        unit = 'Reported motor-vehicle-theft offenses'
    }
    artifacts = @($artifacts)
}

$manifestJson = $manifest | ConvertTo-Json -Depth 8
[System.IO.File]::WriteAllText(
    $manifestPath,
    $manifestJson + [Environment]::NewLine,
    (New-Object System.Text.UTF8Encoding($false))
)

Write-Output "Built $($rows.Count) monthly rows covering $($rows[0].month) through $($rows[-1].month)."
Write-Output "Source last refreshed: $($source.cde_properties.last_refresh_date.UCR)"
Write-Output "Manifest: $manifestPath"