#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'

DATA_DIR="./mcsh"
mkdir -p "$DATA_DIR"

VERSIONS_DIR="$DATA_DIR/versions"
LIBRARIES_DIR="$DATA_DIR/libraries"
NATIVES_DIR="$DATA_DIR/natives"
ASSETS_DIR="$DATA_DIR/assets"
GAME_DIR="$DATA_DIR/run"

function auth (
    CLIENT_ID="9e97542c-b7d5-4a02-a656-4559dad4590a"
    DEVICE_CODE_URL="https://login.microsoftonline.com/consumers/oauth2/v2.0/devicecode"
    TOKEN_URL="https://login.microsoftonline.com/consumers/oauth2/v2.0/token"
    XBL_AUTH_URL="https://user.auth.xboxlive.com/user/authenticate"
    XSTS_TOKEN_URL="https://xsts.auth.xboxlive.com/xsts/authorize"
    MC_AUTH_URL="https://api.minecraftservices.com/authentication/login_with_xbox"

    profile="${1:-"<unknown>"}"

    if ! [[ -e "$DATA_DIR/profiles.json" ]]; then
        printf '{}\n' > "$DATA_DIR/profiles.json"
    fi

    function login (
        printf 'getting device code\n' >&2
        res="$(curl -s -X POST "$DEVICE_CODE_URL" -H 'Content-Type: application/x-www-form-urlencoded' -d "client_id=$CLIENT_ID&scope=XboxLive.signin%20offline_access")"
        device_code="$(<<<"$res" jq -r '.device_code')"
        message="$(<<<"$res" jq -r '.message')"

        printf '%s\n' "$message" >&2

        printf 'waiting for token...\n' >&2
        pending=true
        while [[ "$pending" == true ]]; do
            res="$(curl -s -X POST "$TOKEN_URL" -H 'Content-Type: application/x-www-form-urlencoded' -d "grant_type=urn:ietf:params:oauth:grant-type:device_code&client_id=$CLIENT_ID&device_code=$device_code")"
            pending="$(<<<"$res" jq -r '.error == "authorization_pending"')"
            sleep 1
        done

        printf '%s\n' "$res"
    )

    if [[ -z "$(jq -r --arg profile "$profile" '.[$profile].refresh_token // ""' "$DATA_DIR/profiles.json")" ]]; then
        printf 'logging in\n' >&2
        res="$(login)"
    else
        printf 'refreshing msa auth\n' >&2
        refresh_token="$(jq -r --arg profile "$profile" '.[$profile].refresh_token // ""' "$DATA_DIR/profiles.json")"
        res="$(curl -s -X POST "$TOKEN_URL" -H 'Content-Type: application/x-www-form-urlencoded' -d "grant_type=refresh_token&client_id=$CLIENT_ID&refresh_token=$refresh_token")"
    fi

    refresh_token="$(<<<"$res" jq -r '.refresh_token')"
    msa_token="$(<<<"$res" jq -r '.access_token')"

    profiles="$(jq --arg profile "$profile" --arg token "$refresh_token" '. + {$profile: {"refresh_token": $token, "type": "msa"}}' "$DATA_DIR/profiles.json")"
    <<<"$profiles" cat > "$DATA_DIR/profiles.json"

    printf 'authenticating with xbox live\n' >&2
    req="$(jq -n --arg token "$msa_token" '{"Properties": {"AuthMethod": "RPS", "SiteName": "user.auth.xboxlive.com", "RpsTicket": "d=\($token)"}, "RelyingParty": "http://auth.xboxlive.com", "TokenType": "JWT"}')"
    res="$(curl -s -X POST "$XBL_AUTH_URL" -H 'Content-Type: application/json' -H 'Accept: application/json' -d "$req")"
    xuid="$(<<<"$res" jq -r '.DisplayClaims.xui[0].uhs')"
    xbl_token="$(<<<"$res" jq -r '.Token')"

    # not 100% sure this is *actually* the xuid, but the game doesnt seem to
    # care, even if passed a nonsense value
    profiles="$(jq --arg profile "$profile" --arg xuid "$xuid" '. + {$profile: .[$profile] + {"xuid": $xuid}}' "$DATA_DIR/profiles.json")"
    <<<"$profiles" cat > "$DATA_DIR/profiles.json"

    printf 'getting xsts token\n' >&2
    req="$(jq -n --arg token "$xbl_token" '{"Properties": {"SandboxId": "RETAIL", "UserTokens": [ $token ]}, "RelyingParty": "rp://api.minecraftservices.com/", "TokenType": "JWT"}')"
    res="$(curl -s -X POST "$XSTS_TOKEN_URL" -H 'Content-Type: application/json' -H 'Accept: application/json' -d "$req")"
    xsts_token="$(<<<"$res" jq -r '.Token')"

    printf 'authenticating with mincraft\n' >&2
    req="$(jq -n --arg xuid "$xuid" --arg token "$xsts_token" '{"identityToken": "XBL3.0 x=\($xuid);\($token)"}')"
    res="$(curl -s -X POST "$MC_AUTH_URL" -H 'Content-Type: application/json' -H 'Accept: application/json' -d "$req")"
    mc_token="$(<<<"$res" jq -r '.access_token')"

    profiles="$(jq --arg profile "$profile" --arg token "$mc_token" '. + {$profile: .[$profile] + {"access_token": $token}}' "$DATA_DIR/profiles.json")"
    <<<"$profiles" cat > "$DATA_DIR/profiles.json"

    # printf '%s\n' "$mc_token"
    printf '%s\n' "$profile"
)

function update_profile (
    MC_PROFILE_URL="https://api.minecraftservices.com/minecraft/profile"

    profile="$1"
    token="$(jq -r --arg profile "$profile" '.[$profile].access_token' "$DATA_DIR/profiles.json")"

    printf 'getting minecraft profile\n' >&2
    res="$(curl -s -X GET "$MC_PROFILE_URL" -H "Authorization: Bearer $token")"
    if [[ -n "$(<<<"$res" jq -r '.error // ""')" ]]; then
        printf 'error: user does not own minecraft\n' >&2
        exit 1
    fi
    
    #TODO: hyphenate uuid, for :sparkles: style :sparkles:
    profiles="$(<<<"$res" jq --arg profile "$profile" --slurpfile profiles "$DATA_DIR/profiles.json" '$profiles[0] + {"\(.name)": $profiles[0].[$profile] + {"player_name": .name, "uuid": .id}} | del(.["<unknown>"])')"
    <<<"$profiles" cat > "$DATA_DIR/profiles.json"

    jq --arg profile "$profile" '.[$profile]' "$DATA_DIR/profiles.json"
)

function update_metadata (
    printf 'updating version manifest\n' >&2
    mkdir -p "$VERSIONS_DIR"
    curl --silent "https://piston-meta.mojang.com/mc/game/version_manifest_v2.json" | jq '{"latest": .latest, "versions": [.versions[] | {"key": .id, "value": .url}] | from_entries}' > "$VERSIONS_DIR/manifest.json"

    version="${1:-"$(jq -r '.latest.release' "$VERSIONS_DIR/manifest.json")"}"

    printf 'updating %s meta %s\n' "$version" >&2
    mkdir -p "$VERSIONS_DIR/$version"
    curl --silent -o "$VERSIONS_DIR/$version/meta.json" "$(jq -r --arg version "$version" '.versions[$version]' $VERSIONS_DIR/manifest.json)"
    meta="$(jq -c --slurpfile info info.json -f meta.jq "$VERSIONS_DIR/$version/meta.json")"

    printf 'updating %s asset index...\n' "$version" >&2
    mkdir -p "$ASSETS_DIR/indexes"
    assets_url="$(<<<"$meta" jq -r '.asset_index')"
    curl --silent -o "$ASSETS_DIR/indexes/$(basename "$assets_url")" "$assets_url"

    printf '%s\n' "$meta"
)

function launch (
    profile="$(update_profile "$(auth "${2:-}")")"
    printf '\n' >&2

    meta="$(update_metadata "${1:-}")"

    export LIBRARIES_DIR
    function download_library {
        if ! [[ -e "$LIBRARIES_DIR/${2:-}" ]]; then
            printf '%s\n' "${1:-}" >&2
            mkdir -p "$(dirname "$LIBRARIES_DIR/${2:-}")"
            curl --silent -o "$LIBRARIES_DIR/${2:-}" "${3:-}"
        fi
    }
    export -f download_library

    export ASSETS_DIR
    function download_asset {
        if ! [[ -e "$ASSETS_DIR/objects/${2:-}" ]]; then
            printf '%s\n' "${1:-}" >&2
            mkdir -p "$(dirname "$ASSETS_DIR/objects/${2:-}")"
            curl --silent -o "$ASSETS_DIR/objects/${2:-}" "https://resources.download.minecraft.net/${2:-}"
        fi
    }
    export -f download_asset

    #TODO: check hash
    version="$(<<<"$meta" jq -r '.version')"
    if ! [[ -e "$VERSIONS_DIR/$version/client.jar" ]]; then
        printf 'downloading %s client jar...\n' "$version" >&2
        <<<"$meta" jq -r '.client_url' | xargs curl --silent -o "$VERSIONS_DIR/$version/client.jar"
    fi

    printf 'downloading libraries...\n' >&2
    <<<"$meta" jq -r '.libraries[] | "\(.name) \(.path) \(.url)"' | xargs -I {} "$SHELL" -c "download_library {}"

    printf 'downloading assets...\n' >&2
    jq -r '.objects | to_entries[] | "\(.key) \(.value.hash[:2])/\(.value.hash)"' "$ASSETS_DIR/indexes/$(basename "$(<<<"$meta" jq -r '.asset_index')")" | xargs -P 10 -I {} "$SHELL" -c "download_asset {}"

    # if ! [[ -e "$VERSIONS_DIR/$version/log4j.xml" ]]; then
    #     printf 'downloading %s log4j config...\n' "$version" >&2
    #     <<<"$meta" jq -r '.logging_config' | xargs curl --silent -o "$VERSIONS_DIR/$version/log4j.xml"
    # fi

    function replace_placeholders {
        cat - | sed \
            -e "s:\${versions_directory}:$VERSIONS_DIR:g" \
            -e "s:\${libraries_directory}:$LIBRARIES_DIR:g" \
            -e "s:\${natives_directory}:$NATIVES_DIR:g" \
            -e "s:\${assets_root}:$ASSETS_DIR:g" \
            -e "s:\${game_directory}:$GAME_DIR:g" \
            \
            -e "s/\${launcher_name}/mcsh/g" \
            -e "s/\${launcher_version}/v0.1.0/g" \
            \
            -e "s/\${auth_player_name}/$(<<<"$profile" jq -r '.player_name')/g" \
            -e "s/\${auth_uuid}/$(<<<"$profile" jq -r '.uuid')/g" \
            -e "s/\${auth_xuid}/$(<<<"$profile" jq -r '.xuid')/g" \
            -e "s/\${user_type}/$(<<<"$profile" jq -r '.type')/g" \
            -e "s/\${auth_access_token}/$(<<<"$profile" jq -r '.access_token')/g"
    }

    printf '\nstarting game :3\n\n' >&2
    <<<"$meta" jq -r '.args.jvm + [.main_class] + .args.game | join(" ")' | replace_placeholders | xargs java
)

launch "$@"