[CmdletBinding()]
param(
    [string]$ConfigPath,
    [string]$DatabaseHost,
    [Nullable[int]]$DatabasePort,
    [string]$DatabaseUser,
    [string]$DatabaseName,
    [switch]$SkipMigration,
    [switch]$ValidateConfigOnly
)

$ErrorActionPreference = "Stop"

# The Go processes emit UTF-8. Without this the console decodes their output
# using the ANSI code page (936 on Simplified Chinese systems) and every
# non-ASCII log line arrives as mojibake.
#
# Setting [Console]::OutputEncoding alone is not enough: PowerShell 5.1 decodes
# child process output by the console code page, so chcp has to change too.
#
# NOTE: keep this file pure ASCII. PowerShell 5.1 reads a .ps1 without a BOM as
# ANSI, and a comment line holding an odd number of UTF-8 high bytes pairs its
# last byte with the newline, swallowing it and commenting out the line below.
try {
    $null = & chcp.com 65001
    [Console]::OutputEncoding = [Text.Encoding]::UTF8
    $OutputEncoding = [Text.Encoding]::UTF8
} catch { }
$workspaceRoot = Split-Path -Parent $PSScriptRoot
$serverDirectory = Join-Path $workspaceRoot "server"
$migrationLog = Join-Path $serverDirectory "temp\startup-migration.log"
$plainPassword = $null

function ConvertFrom-YamlScalar {
    param([string]$Value)

    $value = $Value.Trim()
    if ($value.Length -ge 2) {
        if ($value.StartsWith('"') -and $value.EndsWith('"')) {
            return $value.Substring(1, $value.Length - 2).Replace('\"', '"').Replace('\\', '\')
        }
        if ($value.StartsWith("'") -and $value.EndsWith("'")) {
            return $value.Substring(1, $value.Length - 2).Replace("''", "'")
        }
    }
    return $value
}

function Read-DatabaseConfig {
    param([string]$Path)

    if (-not (Test-Path -LiteralPath $Path -PathType Leaf)) {
        throw "Local configuration file was not found: $Path. Copy config.example.yaml to config.yaml and fill in database.password."
    }

    $values = @{}
    $insideDatabase = $false
    foreach ($line in Get-Content -LiteralPath $Path) {
        if ($line -match '^\s*(#.*)?$') {
            continue
        }
        if ($line -match '^database\s*:\s*$') {
            $insideDatabase = $true
            continue
        }
        if ($insideDatabase -and $line -match '^\S') {
            break
        }
        if ($insideDatabase -and $line -match '^\s+(host|port|user|password|name)\s*:\s*(.*?)\s*$') {
            $values[$Matches[1]] = ConvertFrom-YamlScalar $Matches[2]
        }
    }

    foreach ($key in 'host', 'port', 'user', 'password', 'name') {
        if (-not $values.ContainsKey($key) -or [string]::IsNullOrWhiteSpace([string]$values[$key])) {
            throw "Missing database.$key in local configuration file: $Path"
        }
    }

    $parsedPort = 0
    if (-not [int]::TryParse($values.port, [ref]$parsedPort) -or $parsedPort -lt 1 -or $parsedPort -gt 65535) {
        throw "database.port must be an integer between 1 and 65535 in: $Path"
    }
    if ($values.user -notmatch '^[A-Za-z0-9_.-]+$') {
        throw "database.user contains unsupported characters in: $Path"
    }
    if ($values.name -notmatch '^[A-Za-z0-9_]+$') {
        throw "database.name contains unsupported characters in: $Path"
    }

    return @{
        Host = [string]$values.host
        Port = $parsedPort
        User = [string]$values.user
        Password = [string]$values.password
        Name = [string]$values.name
    }
}

function Read-PortConfig {
    param([string]$Path)

    $values = @{}
    $insidePorts = $false
    foreach ($line in Get-Content -LiteralPath $Path) {
        if ($line -match '^\s*(#.*)?$') {
            continue
        }
        if ($line -match '^ports\s*:\s*$') {
            $insidePorts = $true
            continue
        }
        if ($insidePorts -and $line -match '^\S') {
            break
        }
        if ($insidePorts -and $line -match '^\s+(server|web)\s*:\s*(.*?)\s*$') {
            $values[$Matches[1]] = ConvertFrom-YamlScalar $Matches[2]
        }
    }

    foreach ($key in 'server', 'web') {
        $parsedPort = 0
        if (-not $values.ContainsKey($key) -or
            -not [int]::TryParse([string]$values[$key], [ref]$parsedPort) -or
            $parsedPort -lt 1 -or $parsedPort -gt 65535) {
            throw "ports.$key must be an integer between 1 and 65535 in: $Path"
        }
        $values[$key] = $parsedPort
    }
    if ($values.server -eq $values.web) {
        throw "ports.server and ports.web must be different in: $Path"
    }

    return @{ Server = [int]$values.server; Web = [int]$values.web }
}

function Resolve-MySqlClient {
    $services = Get-CimInstance Win32_Service -ErrorAction SilentlyContinue |
        Where-Object { $_.Name -match '^MySQL' -and $_.State -eq 'Running' }
    foreach ($service in $services) {
        if ($service.PathName -match '^"?(.*?\\mysqld\.exe)"?(?:\s|$)') {
            $serviceClient = Join-Path (Split-Path -Parent $Matches[1]) 'mysql.exe'
            if (Test-Path -LiteralPath $serviceClient) {
                return $serviceClient
            }
        }
    }

    $defaultPath = "C:\Program Files\MySQL\MySQL Server 8.4\bin\mysql.exe"
    if (Test-Path -LiteralPath $defaultPath) {
        return $defaultPath
    }

    $command = Get-Command mysql.exe -ErrorAction SilentlyContinue
    if ($command) {
        return $command.Source
    }

    throw "mysql.exe was not found. Add the MySQL 8.4 bin directory to PATH."
}

try {
    if ([string]::IsNullOrWhiteSpace($ConfigPath)) {
        $ConfigPath = Join-Path $workspaceRoot "config.yaml"
    }
    elseif (-not [IO.Path]::IsPathRooted($ConfigPath)) {
        $ConfigPath = Join-Path $workspaceRoot $ConfigPath
    }
    $ConfigPath = [IO.Path]::GetFullPath($ConfigPath)
    $databaseConfig = Read-DatabaseConfig $ConfigPath
    $portConfig = Read-PortConfig $ConfigPath

    if (-not $PSBoundParameters.ContainsKey('DatabaseHost')) {
        $DatabaseHost = $databaseConfig.Host
    }
    if (-not $PSBoundParameters.ContainsKey('DatabasePort')) {
        $DatabasePort = $databaseConfig.Port
    }
    if (-not $PSBoundParameters.ContainsKey('DatabaseUser')) {
        $DatabaseUser = $databaseConfig.User
    }
    if (-not $PSBoundParameters.ContainsKey('DatabaseName')) {
        $DatabaseName = $databaseConfig.Name
    }
    $plainPassword = $databaseConfig.Password

    Write-Host "GoAuto local server" -ForegroundColor Cyan
    Write-Host "Config: $ConfigPath"
    Write-Host "MySQL: ${DatabaseUser}@${DatabaseHost}:${DatabasePort}/${DatabaseName}"
    Write-Host "Ports: server=$($portConfig.Server), web=$($portConfig.Web)"
    if ($ValidateConfigOnly) {
        Write-Host "Local database and port configuration is valid." -ForegroundColor Green
        return
    }

    $mysqlClient = Resolve-MySqlClient
    $env:MYSQL_PWD = $plainPassword
    try {
        Write-Host "[1/3] Checking database ${DatabaseName}..." -ForegroundColor Cyan
        & $mysqlClient `
            --protocol=TCP `
            --host=$DatabaseHost `
            --port=$DatabasePort `
            --user=$DatabaseUser `
            --default-character-set=utf8mb4 `
            --execute="CREATE DATABASE IF NOT EXISTS ``${DatabaseName}`` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;"
        if ($LASTEXITCODE -ne 0) {
            throw "MySQL connection or database creation failed."
        }
    }
    finally {
        Remove-Item Env:MYSQL_PWD -ErrorAction SilentlyContinue
    }

    # Let the server read the same config.yaml for local values such as the SYB
    # credentials. The GOAUTO_* variables below outrank the file, so the
    # database and port stay exactly what this script computed.
    $env:GOAUTO_CONFIG = $ConfigPath
    $env:GOAUTO_DB_DRIVER = "mysql"
    $env:GOAUTO_DB_DSN = "${DatabaseUser}:${plainPassword}@tcp(${DatabaseHost}:${DatabasePort})/${DatabaseName}?charset=utf8mb4&parseTime=True&loc=Local&timeout=5s"
    $env:GOAUTO_SERVER_PORT = [string]$portConfig.Server

    Push-Location $serverDirectory
    try {
        if (-not $SkipMigration) {
            Write-Host "[2/3] Running database migrations..." -ForegroundColor Cyan
            New-Item -ItemType Directory -Path (Split-Path -Parent $migrationLog) -Force | Out-Null
            $previousErrorActionPreference = $ErrorActionPreference
            try {
                $ErrorActionPreference = "Continue"
                # Stringify before Tee-Object. With a bare `2>&1 |`, PowerShell wraps
                # every line the child writes to stderr in an ErrorRecord, which prints
                # as a red NativeCommandError block and reads as a failed migration --
                # even for ordinary informational output such as go-admin's
                # "config init". Chasing individual stderr writers is whack-a-mole; this
                # fixes the whole class. $LASTEXITCODE still reports the child's real
                # exit code through the added pipeline stage, so failure detection below
                # is unaffected.
                & go run . migrate -c config/settings.yml 2>&1 |
                    ForEach-Object { "$_" } |
                    Tee-Object -FilePath $migrationLog
                $migrationExitCode = $LASTEXITCODE
            }
            finally {
                $ErrorActionPreference = $previousErrorActionPreference
            }
            if ($migrationExitCode -ne 0) {
                $migrationTail = (Get-Content -LiteralPath $migrationLog -Tail 40 -ErrorAction SilentlyContinue) -join [Environment]::NewLine
                throw "Database migration failed. Log: ${migrationLog}`n${migrationTail}"
            }
        }
        else {
            Write-Host "[2/3] Database migration skipped." -ForegroundColor DarkYellow
        }

        Write-Host "[3/3] Starting server..." -ForegroundColor Green
        Write-Host "Local URL: http://127.0.0.1:$($portConfig.Server)"
        Write-Host "Android URL: use this computer's LAN IP on port $($portConfig.Server)"
        Write-Host "Press Ctrl+C to stop." -ForegroundColor DarkYellow
        & go run . server -c config/settings.yml
        if ($LASTEXITCODE -ne 0) {
            throw "Server exited with code $LASTEXITCODE."
        }
    }
    finally {
        Pop-Location
    }
}
finally {
    Remove-Item Env:MYSQL_PWD -ErrorAction SilentlyContinue
    Remove-Item Env:GOAUTO_DB_DSN -ErrorAction SilentlyContinue
    Remove-Item Env:GOAUTO_DB_DRIVER -ErrorAction SilentlyContinue
    Remove-Item Env:GOAUTO_SERVER_PORT -ErrorAction SilentlyContinue
    Remove-Item Env:GOAUTO_CONFIG -ErrorAction SilentlyContinue
    $plainPassword = $null
}