#!powershell

# Copyright: (c) 2015, Paul Durivage <paul.durivage@rackspace.com>
# Copyright: (c) 2015, Tal Auslander <tal@cloudshare.com>
# Copyright: (c) 2017, Dag Wieers <dag@wieers.com>
# Copyright: (c) 2019, Viktor Utkin <viktor_utkin@epam.com>
# Copyright: (c) 2019, Uladzimir Klybik <uladzimir_klybik@epam.com>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

#AnsibleRequires -CSharpUtil Ansible.Basic
#Requires -Module Ansible.ModuleUtils.AddType
#Requires -Module Ansible.ModuleUtils.FileUtil

$spec = @{
    options = @{
        url = @{ type='str'; required=$true }
        dest = @{ type='path'; required=$true }
        timeout = @{ type='int'; default=10 }
        headers = @{ type='dict'; default=@{} }
        validate_certs = @{ type='bool'; default=$true }
        url_username = @{ type='str'; aliases=@( 'username' ) }
        url_password = @{ type='str'; aliases=@( 'password' ); no_log=$true }
        force_basic_auth = @{ type='bool'; default=$false }
        use_proxy = @{ type='bool'; default=$true }
        proxy_url = @{ type='str' }
        proxy_username = @{ type='str' }
        proxy_password = @{ type='str'; no_log=$true }
        force = @{ type='bool'; default=$true }
        checksum = @{ type='str' }
        checksum_algorithm = @{ type='str'; default='sha1'; choices = @("md5", "sha1", "sha256", "sha384", "sha512") }
        checksum_url = @{ type='str' }
    }
    mutually_exclusive = @(
        ,@('checksum', 'checksum_url')
    )
    supports_check_mode = $true
}

$module = [Ansible.Basic.AnsibleModule]::Create($args, $spec)

$url = $module.Params.url
$dest = $module.Params.dest
$timeout = $module.Params.timeout
$headers = $module.Params.headers
$validate_certs = $module.Params.validate_certs
$url_username = $module.Params.url_username
$url_password = $module.Params.url_password
$force_basic_auth = $module.Params.force_basic_auth
$use_proxy = $module.Params.use_proxy
$proxy_url = $module.Params.proxy_url
$proxy_username = $module.Params.proxy_username
$proxy_password = $module.Params.proxy_password
$force = $module.Params.force
$checksum = $module.Params.checksum
$checksum_algorithm = $module.Params.checksum_algorithm
$checksum_url = $module.Params.checksum_url

$module.Result.elapsed = 0
$module.Result.url = $url

Function Invoke-AnsibleWebRequest {
    <#
    .SYNOPSIS
    Creates a WebRequest and invokes a ScriptBlock with the response passed in.
    It handles the common module options like credential, timeout, proxy options
    in a single location to reduce code duplication.
    #>
    param(
        [Parameter(Mandatory=$true)][Ansible.Basic.AnsibleModule]$Module,
        [Parameter(Mandatory=$true)][Uri]$Uri,
        [Parameter(Mandatory=$true)][Hashtable]$Method,
        [Parameter(Mandatory=$true)][ScriptBlock]$Script, # Invoked in this cmdlet
        [System.Collections.IDictionary]$Headers,
        [Int32]$Timeout,
        [Switch]$UseProxy,
        [System.Net.WebProxy]$Proxy,
        $Credential  # Either a String (force_basic_auth) or NetCredentials
    )

    $web_request = [System.Net.WebRequest]::Create($Uri)
    $web_request.Method = $Method.($web_request.GetType().Name)

    foreach ($header in $headers.GetEnumerator()) {
        # some headers need to be set on the property itself
        switch ($header.Key) {
            Accept { $web_request.Accept = $header.Value }
            Connection { $web_request.Connection = $header.Value }
            Content-Length { $web_request.ContentLength = $header.Value }
            Content-Type { $web_request.ContentType = $header.Value }
            Expect { $web_request.Expect = $header.Value }
            Date { $web_request.Date = $header.Value }
            Host { $web_request.Host = $header.Value }
            If-Modified-Since { $web_request.IfModifiedSince = $header.Value }
            Range { $web_request.AddRange($header.Value) }
            Referer { $web_request.Referer = $header.Value }
            Transfer-Encoding {
                $web_request.SendChunked = $true
                $web_request.TransferEncoding = $header.Value
            }
            User-Agent { $web_request.UserAgent = $header.Value }
            default { $web_request.Headers.Add($header.Key, $header.Value) }
        }
    }

    if ($timeout) {
        $web_request.Timeout = $timeout * 1000
    }

    if (-not $UseProxy) {
        $web_request.Proxy = $null
    } elseif ($ProxyUri) {
        $web_request.Proxy = $Proxy
    }

    if ($Credential) {
        if ($Credential -is [String]) {
            # force_basic_auth=yes is set
            $web_request.Headers.Add("Authorization", "Basic $Credential")
        } else {
            $web_request.Credentials = $Credential
        }
    }

    try {
        $web_response = $web_request.GetResponse()
        $response_stream = $web_response.GetResponseStream()
        try {
            # Invoke the ScriptBlock and pass in the WebResponse and ResponseStream
            &$Script -Response $web_response -Stream $response_stream
        } finally {
            $response_stream.Dispose()
        }

        if ($Uri.IsFile) {
            # A FileWebResponse won't have these properties set
            $module.Result.msg = "OK"
            $module.Result.status_code = 200
        } else {
            $module.Result.msg = [string]$web_response.StatusDescription
            $module.Result.status_code = [int]$web_response.StatusCode
        }
    } catch [System.Net.WebException] {
        $module.Result.status_code = [int]$_.Exception.Response.StatusCode
        $module.FailJson("Error requesting '$Uri'. $($_.Exception.Message)", $_)
    } finally {
        if ($web_response) {
            $web_response.Close()
        }
    }
}

Function Get-ChecksumFromUri {
    param(
        [Parameter(Mandatory=$true)][Ansible.Basic.AnsibleModule]$Module,
        [Parameter(Mandatory=$true)][Uri]$Uri,
        [Uri]$SourceUri,
        [Hashtable]$RequestParams
    )

    $script = {
        param($Response, $Stream)

        $read_stream = New-Object -TypeName System.IO.StreamReader -ArgumentList $Stream
        $web_checksum = $read_stream.ReadToEnd()
        $basename = (Split-Path -Path $SourceUri.LocalPath -Leaf)
        $basename = [regex]::Escape($basename)
        $web_checksum_str = $web_checksum -split '\r?\n' | Select-String -Pattern $("\s+\.?\/?\\?" + $basename + "\s*$")
        if (-not $web_checksum_str) {
            $Module.FailJson("Checksum record not found for file name '$basename' in file from url: '$Uri'")
        }

        $web_checksum_str_splitted = $web_checksum_str[0].ToString().split(" ", 2)
        $hash_from_file = $web_checksum_str_splitted[0].Trim()
        # Remove any non-alphanumeric characters
        $hash_from_file = $hash_from_file -replace '\W+', ''

        Write-Output -InputObject $hash_from_file
    }
    $invoke_args = @{
        Module = $Module
        Uri = $Uri
        Method = @{
            FileWebRequest = [System.Net.WebRequestMethods+File]::DownloadFile
            FtpWebRequest = [System.Net.WebRequestMethods+Ftp]::DownloadFile
            HttpWebRequest = [System.Net.WebRequestMethods+Http]::Get
        }
        Script = $script
    }
    try {
        Invoke-AnsibleWebRequest @invoke_args @RequestParams
    } catch {
        $Module.FailJson("Error when getting the remote checksum from '$Uri'. $($_.Exception.Message)", $_)
    }
}

Function Compare-ModifiedFile {
    <#
    .SYNOPSIS
    Compares the remote URI resource against the local Dest resource. Will
    return true if the LastWriteTime/LastModificationDate of the remote is
    newer than the local resource date.
    #>
    param(
        [Parameter(Mandatory=$true)][Ansible.Basic.AnsibleModule]$Module,
        [Parameter(Mandatory=$true)][Uri]$Uri,
        [Parameter(Mandatory=$true)][String]$Dest,
        [Hashtable]$RequestParams
    )

    $dest_last_mod = (Get-AnsibleItem -Path $Dest).LastWriteTimeUtc

    # If the URI is a file we don't need to go through the whole WebRequest
    if ($Uri.IsFile) {
        $src_last_mod = (Get-AnsibleItem -Path $Uri.AbsolutePath).LastWriteTimeUtc
    } else {
        $invoke_args = @{
            Module = $Module
            Uri = $Uri
            Method = @{
                FtpWebRequest = [System.Net.WebRequestMethods+Ftp]::GetDateTimestamp
                HttpWebRequest = [System.Net.WebRequestMethods+Http]::Head
            }
            Script = { param($Response, $Stream); $Response.LastModified }
        }
        try {
            $src_last_mod = Invoke-AnsibleWebRequest @invoke_args @RequestParams
        } catch {
            $Module.FailJson("Error when requesting 'Last-Modified' date from '$Uri'. $($_.Exception.Message)", $_)
        }
    }

    # Return $true if the Uri LastModification date is newer than the Dest LastModification date
    ((Get-Date -Date $src_last_mod).ToUniversalTime() -gt $dest_last_mod)
}

Function Get-Checksum {
    param(
        [Parameter(Mandatory=$true)][String]$Path,
        [String]$Algorithm = "sha1"
    )

    switch ($Algorithm) {
        'md5' { $sp = New-Object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider }
        'sha1' { $sp = New-Object -TypeName System.Security.Cryptography.SHA1CryptoServiceProvider }
        'sha256' { $sp = New-Object -TypeName System.Security.Cryptography.SHA256CryptoServiceProvider }
        'sha384' { $sp = New-Object -TypeName System.Security.Cryptography.SHA384CryptoServiceProvider }
        'sha512' { $sp = New-Object -TypeName System.Security.Cryptography.SHA512CryptoServiceProvider }
    }

    $fs = [System.IO.File]::Open($Path, [System.IO.Filemode]::Open, [System.IO.FileAccess]::Read,
        [System.IO.FileShare]::ReadWrite)
    try {
        $hash = [System.BitConverter]::ToString($sp.ComputeHash($fs)).Replace("-", "").ToLower()
    } finally {
        $fs.Dispose()
    }
    return $hash
}

Function Invoke-DownloadFile {
    param(
        [Parameter(Mandatory=$true)][Ansible.Basic.AnsibleModule]$Module,
        [Parameter(Mandatory=$true)][Uri]$Uri,
        [Parameter(Mandatory=$true)][String]$Dest,
        [String]$Checksum,
        [String]$ChecksumAlgorithm,
        [Hashtable]$RequestParams
    )

    # Check $dest parent folder exists before attempting download, which avoids unhelpful generic error message.
    $dest_parent = Split-Path -LiteralPath $Dest
    if (-not (Test-Path -LiteralPath $dest_parent -PathType Container)) {
        $module.FailJson("The path '$dest_parent' does not exist for destination '$Dest', or is not visible to the current user.  Ensure download destination folder exists (perhaps using win_file state=directory) before win_get_url runs.")
    }

    $download_script = {
        param($Response, $Stream)

        # Download the file to a temporary directory so we can compare it
        $tmp_dest = Join-Path -Path $Module.Tmpdir -ChildPath ([System.IO.Path]::GetRandomFileName())
        $fs = [System.IO.File]::Create($tmp_dest)
        try {
            $Stream.CopyTo($fs)
            $fs.Flush()
        } finally {
            $fs.Dispose()
        }
        $tmp_checksum = Get-Checksum -Path $tmp_dest -Algorithm $ChecksumAlgorithm
        $Module.Result.checksum_src = $tmp_checksum

        # If the checksum has been set, verify the checksum of the remote against the input checksum.
        if ($Checksum -and $Checksum -ne $tmp_checksum) {
            $Module.FailJson(("The checksum for {0} did not match '{1}', it was '{2}'" -f $Uri, $Checksum, $tmp_checksum))
        }

        $download = $true
        if (Test-Path -LiteralPath $Dest) {
            # Validate the remote checksum against the existing downloaded file
            $dest_checksum = Get-Checksum -Path $Dest -Algorithm $ChecksumAlgorithm

            # If we don't need to download anything, save the dest checksum so we don't waste time calculating it
            # again at the end of the script
            if ($dest_checksum -eq $tmp_checksum) {
                $download = $false
                $Module.Result.checksum_dest = $dest_checksum
                $Module.Result.size = (Get-AnsibleItem -Path $Dest).Length
            }
        }

        if ($download) {
            Copy-Item -LiteralPath $tmp_dest -Destination $Dest -Force -WhatIf:$Module.CheckMode > $null
            $Module.Result.changed = $true
        }
    }

    $invoke_args = @{
        Module = $Module
        Uri = $Uri
        Method = @{
            FileWebRequest = [System.Net.WebRequestMethods+File]::DownloadFile
            FtpWebRequest = [System.Net.WebRequestMethods+Ftp]::DownloadFile
            HttpWebRequest = [System.Net.WebRequestMethods+Http]::Get
        }
        Script = $download_script
    }

    $module_start = Get-Date
    try {
        Invoke-AnsibleWebRequest @invoke_args @RequestParams
    } catch {
        $Module.FailJson("Unknown error downloading '$Uri' to '$Dest': $($_.Exception.Message)", $_)
    } finally {
        $Module.Result.elapsed = ((Get-Date) - $module_start).TotalSeconds
    }
}

if (-not $use_proxy -and ($proxy_url -or $proxy_username -or $proxy_password)) {
    $module.Warn("Not using a proxy on request, however a 'proxy_url', 'proxy_username' or 'proxy_password' was defined.")
}

$proxy = $null
if ($proxy_url) {
    $proxy = New-Object System.Net.WebProxy($proxy_url, $true)
    if ($proxy_username -and $proxy_password) {
        $proxy_credential = New-Object System.Net.NetworkCredential($proxy_username, $proxy_password)
        $proxy.Credentials = $proxy_credential
    }
}

$credentials = $null
if ($url_username) {
    if ($force_basic_auth) {
        $credentials = [convert]::ToBase64String([System.Text.Encoding]::ASCII.GetBytes($url_username+":"+$url_password))
    } else {
        $credentials = New-Object System.Net.NetworkCredential($url_username, $url_password)
    }
}

if (-not $validate_certs) {
    [System.Net.ServicePointManager]::ServerCertificateValidationCallback = { $true }
}

# Use last part of url for dest file name if a directory is supplied for $dest
if (Test-Path -LiteralPath $dest -PathType Container) {
    $uri = [System.Uri]$url
    $basename = Split-Path -Path $uri.LocalPath -Leaf
    if ($uri.LocalPath -and $uri.LocalPath -ne '/' -and $basename) {
        $url_basename = Split-Path -Path $uri.LocalPath -Leaf
        $dest = Join-Path -Path $dest -ChildPath $url_basename
    } else {
        $dest = Join-Path -Path $dest -ChildPath $uri.Host
    }

    # Ensure we have a string instead of a PS object to avoid serialization issues
    $dest = $dest.ToString()
} elseif (([System.IO.Path]::GetFileName($dest)) -eq '') {
    # We have a trailing path separator
    $module.FailJson("The destination path '$dest' does not exist, or is not visible to the current user.  Ensure download destination folder exists (perhaps using win_file state=directory) before win_get_url runs.")
}

$module.Result.dest = $dest

# Enable TLS1.1/TLS1.2 if they're available but disabled (eg. .NET 4.5)
$security_protocols = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::SystemDefault
if ([Net.SecurityProtocolType].GetMember("Tls11").Count -gt 0) {
    $security_protocols = $security_protocols -bor [Net.SecurityProtocolType]::Tls11
}
if ([Net.SecurityProtocolType].GetMember("Tls12").Count -gt 0) {
    $security_protocols = $security_protocols -bor [Net.SecurityProtocolType]::Tls12
}
[Net.ServicePointManager]::SecurityProtocol = $security_protocols

$request_params = @{
    Credential = $credentials
    Headers = $headers
    Timeout = $timeout
    UseProxy = $use_proxy
    Proxy = $proxy
}

if ($checksum) {
    $checksum = $checksum.Trim().ToLower()
}
if ($checksum_algorithm) {
    $checksum_algorithm = $checksum_algorithm.Trim().ToLower()
}
if ($checksum_url) {
    $checksum_url = $checksum_url.Trim()
}

# Check for case $checksum variable contain url. If yes, get file data from url and replace original value in $checksum
if ($checksum_url) {
    $checksum_uri = [System.Uri]$checksum_url
    if ($checksum_uri.Scheme -notin @("file", "ftp", "http", "https")) {
        $module.FailJson("Unsupported 'checksum_url' value for '$dest': '$checksum_url'")
    }

    $checksum = Get-ChecksumFromUri -Module $Module -Uri $checksum_uri -SourceUri $url -RequestParams $request_params
}

if ($force -or -not (Test-Path -LiteralPath $dest)) {
    # force=yes or dest does not exist, download the file
    # Note: Invoke-DownloadFile will compare the checksums internally if dest exists
    Invoke-DownloadFile -Module $module -Uri $url -Dest $dest -Checksum $checksum `
        -ChecksumAlgorithm $checksum_algorithm -RequestParams $request_params
} else {
    # force=no, we want to check the last modified dates and only download if they don't match
    $is_modified = Compare-ModifiedFile -Module $module -Uri $url -Dest $dest -RequestParams $request_params
    if ($is_modified) {
        Invoke-DownloadFile -Module $module -Uri $url -Dest $dest -Checksum $checksum `
            -ChecksumAlgorithm $checksum_algorithm -RequestParams $request_params
   }
}

if ((-not $module.Result.ContainsKey("checksum_dest")) -and (Test-Path -LiteralPath $dest)) {
    # Calculate the dest file checksum if it hasn't already been done
    $module.Result.checksum_dest = Get-Checksum -Path $dest -Algorithm $checksum_algorithm
    $module.Result.size = (Get-AnsibleItem -Path $dest).Length
}

$module.ExitJson()

