#!/usr/bin/env nix-shell
#!nix-shell -I nixpkgs=./. -i bash -p curl jq nix gnused nixfmt
# shellcheck shell=bash

set -Eeuo pipefail
shopt -s inherit_errexit

trap 'exit 1' ERR

rids=()

release () {
  local content="$1"
  local version="$2"

  jq -er '.releases[] | select(."release-version" == "'"$version"'")' <<< "$content"
}

release_files () {
  local release="$1"
  local expr="$2"

  jq -er '[('"$expr"').files[] | select(.name | test("^.*.tar.gz$"))]' <<< "$release"
}

release_platform_attr () {
  local release_files="$1"
  local platform="$2"
  local attr="$3"

  jq -r '.[] | select((.rid == "'"$platform"'") and (.name | contains("-composite-") or contains("-pack-") | not)) | ."'"$attr"'"' <<< "$release_files"
}

platform_sources () {
  local release_files="$1"

  echo "srcs = {"
  for rid in "${rids[@]}"; do
    local url hash

    url=$(release_platform_attr "$release_files" "$rid" url)
    hash=$(release_platform_attr "$release_files" "$rid" hash)

    [[ -z "$url" || -z "$hash" ]] && continue

    hash=$(nix --extra-experimental-features nix-command hash convert --to sri --hash-algo sha512 "$hash")

    echo "      $rid = {
        url = \"$url\";
        hash = \"$hash\";
      };"
  done
  echo "    };"
}

nuget_index="$(curl -fsSL "https://api.nuget.org/v3/index.json")"

get_nuget_resource() {
  jq -er '.resources[] | select(."@type" == "'"$1"'")."@id"' <<<"$nuget_index"
}

nuget_package_base_url="$(get_nuget_resource "PackageBaseAddress/3.0.0")"
nuget_registration_base_url="$(get_nuget_resource "RegistrationsBaseUrl/3.6.0")"

generate_package_list() {
  local version="$1" indent="$2"
  shift 2
  local pkgs=( "$@" ) pkg url hash catalog_url catalog hash_algorithm

  for pkg in "${pkgs[@]}"; do
    url=${nuget_package_base_url}${pkg,,}/${version,,}/${pkg,,}.${version,,}.nupkg

    if hash=$(curl -s --head "$url" -o /dev/null -w '%header{x-ms-meta-sha512}') && [[ -n "$hash" ]]; then
      # Undocumented fast path for nuget.org
      # https://github.com/NuGet/NuGetGallery/issues/9433#issuecomment-1472286080
      hash=$(nix --extra-experimental-features nix-command hash convert --to sri --hash-algo sha512 "$hash")
    elif {
      catalog_url=$(curl -sL --compressed "${nuget_registration_base_url}${pkg,,}/${version,,}.json" | jq -r ".catalogEntry") && [[ -n "$catalog_url" ]] &&
        catalog=$(curl -sL "$catalog_url") && [[ -n "$catalog" ]] &&
        hash_algorithm="$(jq -er '.packageHashAlgorithm' <<<"$catalog")"&& [[ -n "$hash_algorithm" ]] &&
        hash=$(jq -er '.packageHash' <<<"$catalog") && [[ -n "$hash" ]]
    }; then
      # Documented but slower path (requires 2 requests)
      hash=$(nix --extra-experimental-features nix-command hash convert --to sri --hash-algo "${hash_algorithm,,}" "$hash")
    elif hash=$(nix-prefetch-url "$url" --type sha512); then
      # Fallback to downloading and hashing locally
      echo "Failed to fetch hash from nuget for $url, falling back to downloading locally" >&2
      hash=$(nix --extra-experimental-features nix-command hash convert --to sri --hash-algo sha512 "$hash")
    else
      echo "Failed to fetch hash for $url" >&2
      exit 1
    fi

    echo "$indent(fetchNupkg { pname = \"${pkg}\"; version = \"${version}\"; hash = \"${hash}\"; })"
  done
}

versionAtLeast () {
  local cur_version=$1 min_version=$2
  printf "%s\0%s" "$min_version" "$cur_version" | sort -zVC
}

# These packages are implicitly references by the build process,
# based on the specific project configurations (RIDs, used features, etc.)
# They are always referenced with the same version as the SDK used for building.
# Since we lock nuget dependencies, when these packages are included in the generated
# lock files (deps.nix), every update of SDK required those lock files to be
# updated to reflect the new versions of these packages - otherwise, the build
# would fail due to missing dependencies.
#
# Moving them to a separate list stored alongside the SDK package definitions,
# and implicitly including them along in buildDotnetModule allows us
# to make updating .NET SDK packages a lot easier - we now just update
# the versions of these packages in one place, and all packages that
# use buildDotnetModule continue building with the new .NET version without changes.
#
# Keep in mind that there is no canonical list of these implicitly
# referenced packages - this list was created based on looking into
# the deps.nix files of existing packages, and which dependencies required
# updating after a SDK version bump.
#
# Due to this, make sure to check if new SDK versions introduce any new packages.
# This should not happend in minor or bugfix updates, but probably happens
# with every new major .NET release.
aspnetcore_packages () {
  local version=$1
  local pkgs=()

  if [[ -z "$vmr_bootstrap" ]]; then
     pkgs+=(
       Microsoft.AspNetCore.App.Ref
     )

    if versionAtLeast "$version" 10; then
      pkgs+=(
        Microsoft.AspNetCore.App.Internal.Assets
      )
    fi
  fi

  generate_package_list "$version" '    ' "${pkgs[@]}"
}

aspnetcore_target_packages () {
  local version=$1 rid=$2
  local pkgs=(
    "Microsoft.AspNetCore.App.Runtime.$rid"
  )

  generate_package_list "$version" '      ' "${pkgs[@]}"
}

netcore_packages () {
  local version=$1
  local pkgs=()

  if [[ -z "$vmr_bootstrap" ]]; then
    pkgs+=(
      Microsoft.NETCore.DotNetAppHost
      Microsoft.NETCore.App.Ref
    )

    if ! versionAtLeast "$version" 9; then
      pkgs+=(
        Microsoft.NETCore.DotNetHost
        Microsoft.NETCore.DotNetHostPolicy
        Microsoft.NETCore.DotNetHostResolver
      )
    fi

    if versionAtLeast "$version" 7; then
      pkgs+=(
        Microsoft.DotNet.ILCompiler
      )
    fi
  fi

  if versionAtLeast "$version" 8; then
    pkgs+=(
      Microsoft.NET.ILLink.Tasks
    )
  fi

  generate_package_list "$version" '    ' "${pkgs[@]}"
}

netcore_host_packages () {
  local version=$1 rid=$2
  local pkgs=(
    "Microsoft.NETCore.App.Crossgen2.$rid"
  )

  if [[ -n "$vmr_bootstrap" ]]; then
    if versionAtLeast "$version" 9; then
      pkgs+=(
        "runtime.$rid.Microsoft.NETCore.ILAsm"
        "runtime.$rid.Microsoft.NETCore.ILDAsm"
        "runtime.$rid.Microsoft.DotNet.ILCompiler"
      )
    fi
  else
    local min_ilcompiler=
    case "$rid" in
      linux-musl-arm) ;;
      linux-arm) ;;
      win-x86) ;;
      osx-arm64) min_ilcompiler=8 ;;
      *) min_ilcompiler=7 ;;
    esac

    if [[ -n "$min_ilcompiler" ]] && versionAtLeast "$version" "$min_ilcompiler"; then
      pkgs+=(
        "runtime.$rid.Microsoft.DotNet.ILCompiler"
      )
    fi
  fi

  generate_package_list "$version" '      ' "${pkgs[@]}"
}

netcore_target_packages () {
  local version=$1 rid=$2
  local pkgs=()

  if [[ -n "$vmr_bootstrap" ]]; then
    pkgs+=(
      "Microsoft.NETCore.App.Runtime.$rid"
    )
  else
    pkgs+=(
      "Microsoft.NETCore.App.Host.$rid"
      "Microsoft.NETCore.App.Runtime.$rid"
      "runtime.$rid.Microsoft.NETCore.DotNetAppHost"
    )

    if ! versionAtLeast "$version" 9; then
      pkgs+=(
        "runtime.$rid.Microsoft.NETCore.DotNetHost"
        "runtime.$rid.Microsoft.NETCore.DotNetHostPolicy"
        "runtime.$rid.Microsoft.NETCore.DotNetHostResolver"
      )
      case "$rid" in
        linux-musl-arm*) ;;
        win-arm64) ;;
        *) pkgs+=(
             "Microsoft.NETCore.App.Runtime.Mono.$rid"
           ) ;;
      esac
    fi

    if versionAtLeast "$version" 10; then
      pkgs+=(
        "Microsoft.NETCore.App.Runtime.NativeAOT.$rid"
      )
    fi
  fi

  generate_package_list "$version" '      ' "${pkgs[@]}"
}

usage () {
  echo "Usage: $pname [[--vmr-bootstrap] [--sdk] [-o output] sem-version] ...
Get updated dotnet src (platform - url & sha512) expressions for specified versions

Exit codes:
  0 Success
  1 Failure
  2 Release not found

Examples:
  $pname 6.0.14 7.0.201    - specific x.y.z versions
  $pname 6.0 7.0           - latest x.y versions
" >&2
}

update() {
  local -r sem_version=$1

  local patch_specified=false
  # Check if a patch was specified as an argument.
  # If so, generate file for the specific version.
  # If only x.y version was provided, get the latest patch
  # version of the given x.y version.
  if [[ "$sem_version" =~ ^[0-9]{1,}\.[0-9]{1,}\.[0-9]{1,} ]]; then
    patch_specified=true
  elif [[ ! "$sem_version" =~ ^[0-9]{1,}\.[0-9]{1,}$ ]]; then
    usage
    return 1
  fi

  : ${output:="$(realpath "$(dirname "${BASH_SOURCE[0]}")")"/../$sem_version/releases.nix}
  echo "Generating $output"

  # Make sure the x.y version is properly passed to .NET release metadata url.
  # Then get the json file and parse it to find the latest patch release.
  local major_minor content major_minor_patch
  major_minor=$(sed 's/^\([0-9]*\.[0-9]*\).*$/\1/' <<< "$sem_version")
  content=$(curl -fsSL https://dotnetcli.blob.core.windows.net/dotnet/release-metadata/"$major_minor"/releases.json)
  if [[ -n $sdk_only ]]; then
    trap '' ERR
    major_minor_patch=$(
      jq -er --arg version "$sem_version" '
                .releases[] |
                select(.sdks[].version == $version) |
                ."release-version"' <<< "$content" || if [[ $? == 4 ]]; then exit 2; else exit 1; fi)
    trap 'exit 1' ERR
  else
    major_minor_patch=$([ "$patch_specified" == true ] && echo "$sem_version" || jq -er '."latest-release"' <<< "$content")
  fi
  local major_minor_underscore=${major_minor/./_}

  local release_content aspnetcore_version runtime_version
  local -a sdk_versions

  release_content=$(release "$content" "$major_minor_patch")
  aspnetcore_version=$(jq -er '."aspnetcore-runtime".version' <<< "$release_content")
  runtime_version=$(jq -er '.runtime.version' <<< "$release_content")

  if [[ -n $sdk_only ]]; then
    sdk_versions=("$sem_version")
  else
    mapfile -t sdk_versions < <(jq -er '.sdks[] | .version' <<< "$release_content" | sort -rn)
  fi

  # If patch was not specified, check if the package is already the latest version
  # If it is, exit early
  if [ "$patch_specified" == false ] && [ -f "$output" ]; then
    local -a versions
    IFS= readarray -d '' versions < <(
      nix-instantiate --eval --json -E "{ output }: with (import output {
                buildAspNetCore = { ... }: {};
                buildNetSdk = { version, ... }: { inherit version; };
                buildNetRuntime = { version, ... }: { inherit version; };
                fetchNupkg = { ... }: {};
            }); (x: builtins.deepSeq x x) [
                runtime_${major_minor_underscore}.version
                sdk_${major_minor_underscore}.version
            ]" --argstr output "$output" | jq -e --raw-output0 .[])
    if [[ "${versions[0]}" == "$major_minor_patch" && "${versions[1]}" == "${sdk_versions[0]}" ]]; then
      echo "Nothing to update."
      return
    fi
  fi

  if [[ -n "$vmr_bootstrap" ]]; then
    rids=({linux-{arm64,x64},osx-{arm64,x64}})
  else
    rids=({linux-{,musl-}{arm,arm64,x64},osx-{arm64,x64},win-{arm64,x64,x86}})
  fi

  local aspnetcore_files runtime_files
  aspnetcore_files="$(release_files "$release_content" .\"aspnetcore-runtime\")"
  runtime_files="$(release_files "$release_content" .runtime)"

  local channel_version support_phase
  channel_version=$(jq -er '."channel-version"' <<< "$content")
  support_phase=$(jq -er '."support-phase"' <<< "$content")

  local aspnetcore_sources runtime_sources
  aspnetcore_sources="$(platform_sources "$aspnetcore_files")"
  runtime_sources="$(platform_sources "$runtime_files")"

  result=$(mktemp -t dotnet-XXXXXX.nix)
  trap "rm -f $result" TERM INT EXIT

  (
    echo "{ buildAspNetCore, buildNetRuntime, buildNetSdk, fetchNupkg }:

# v$channel_version ($support_phase)

let
  commonPackages = ["
    aspnetcore_packages "${aspnetcore_version}"
    netcore_packages "${runtime_version}"
    echo "  ];

  hostPackages = {"
    for rid in "${rids[@]}"; do
      echo "    $rid = ["
      netcore_host_packages "${runtime_version}" "$rid"
      echo "    ];"
    done
    echo "  };

  targetPackages = {"
    for rid in "${rids[@]}"; do
      echo "    $rid = ["
      aspnetcore_target_packages "${aspnetcore_version}" "$rid"
      netcore_target_packages "${runtime_version}" "$rid"
      echo "    ];"
    done
    echo "  };

in rec {
  release_$major_minor_underscore = \"$major_minor_patch\";

  aspnetcore_$major_minor_underscore = buildAspNetCore {
    version = \"${aspnetcore_version}\";
    $aspnetcore_sources
  };

  runtime_$major_minor_underscore = buildNetRuntime {
    version = \"${runtime_version}\";
    $runtime_sources
  };"

    local -A feature_bands
    unset latest_sdk

    for sdk_version in "${sdk_versions[@]}"; do
      local sdk_base_version=${sdk_version%-*}
      local feature_band=${sdk_base_version:0:-2}xx
      # sometimes one release has e.g. both 8.0.202 and 8.0.203
      [[ ! ${feature_bands[$feature_band]+true} ]] || continue
      feature_bands[$feature_band]=$sdk_version
      local sdk_files sdk_sources
      sdk_files="$(release_files "$release_content" ".sdks[] | select(.version == \"$sdk_version\")")"
      sdk_sources="$(platform_sources "$sdk_files")"
      local sdk_attrname=sdk_${feature_band//./_}
      [[ -v latest_sdk ]] || local latest_sdk=$sdk_attrname

      echo "
  $sdk_attrname = buildNetSdk {
    version = \"${sdk_version}\";
    $sdk_sources
    inherit commonPackages hostPackages targetPackages;
    runtime = runtime_$major_minor_underscore;
    aspnetcore = aspnetcore_$major_minor_underscore;
  };"
    done

    if [[ -n $sdk_only ]]; then
      echo "
  sdk = sdk_$major_minor_underscore;
"
    fi

    echo "
  sdk_$major_minor_underscore = $latest_sdk;
}"
  )> "$result"

  nixfmt "$result"
  mkdir -p "$(dirname -- "$output")"
  cp "$result" "$output"
  echo "Generated $output"
}

main () {
  local pname
  pname=$(basename "$0")

  vmr_bootstrap=
  sdk_only=
  output=

  while [ $# -gt 0 ]; do
    case $1 in
      --vmr-bootstrap)
        shift
        vmr_bootstrap=1
        ;;
      --sdk)
        shift
        sdk_only=1
        ;;
      -o)
        shift
        output=$1
        shift
        ;;
      *)
        update "$1"
        output=
        shift
        ;;
    esac
  done
}

main "$@"