#!/bin/bash

set -euo pipefail

readonly LINE="=================================================="
readonly SUBLINE="--------------------------------------------------"

section() {
    printf '\n%s\n%s\n%s\n' "$LINE" "$1" "$SUBLINE"
}

info() {
    printf '[info] %s\n' "$1"
}

fail() {
    printf '[error] %s\n' "$1" >&2
    exit 1
}

require_env() {
    local name="$1"
    local value="$2"

    if [ -z "$value" ] || [ "$value" = "null" ]; then
        fail "$name 未設定"
    fi

    printf '%s=%s\n' "$name" "$value"
}

write_output() {
    printf 'version=%s\n' "$1" >> "$GITHUB_OUTPUT"
}

normalize_beta_flag() {
    local value="${1:-false}"

    if [ -z "$value" ] || [ "$value" = "null" ]; then
        printf '%s\n' "false"
        return
    fi

    printf '%s\n' "$value"
}

latest_stable_version() {
    local release_json="$1"

    if [ -z "$release_json" ] || [ "$release_json" = "null" ]; then
        printf '%s\n' "0.0.0"
        return
    fi

    printf '%s' "$release_json" | jq -r '
        if type == "array" then
            [ .[] | select(.tag_name? and (.tag_name | test("-beta\\.") | not)) | .tag_name ][0]
                // "v0.0.0"
        else
            "v0.0.0"
        end
        | sub("^v"; "")
    '
}

next_release_version() {
    local latest_version="$1"
    local major minor patch

    IFS='.' read -r major minor patch <<< "$latest_version"
    major="${major:-0}"
    minor="${minor:-0}"
    patch="${patch:-0}"

    patch=$((patch + 1))
    if [ "$patch" -ge 10 ]; then
        patch=0
        minor=$((minor + 1))
    fi

    if [ "$minor" -ge 10 ]; then
        minor=0
        major=$((major + 1))
    fi

    printf '%s.%s.%s\n' "$major" "$minor" "$patch"
}

next_beta_number() {
    local release_json="$1"
    local version="$2"

    if [ -z "$release_json" ] || [ "$release_json" = "null" ]; then
        printf '%s\n' "1"
        return
    fi

    printf '%s' "$release_json" | jq -r --arg prefix "v${version}-beta." '
        if type == "array" then
            [ .[] 
              | select(.tag_name? and (.tag_name | startswith($prefix)))
              | .tag_name
              | ltrimstr($prefix)
              | try tonumber catch empty
            ] | if length > 0 then max else 0 end
        else
            0
        end
    ' | awk '{print $1 + 1}'
}

calculate_version() {
    local release_json="$1"
    local is_beta="$2"

    if [ -z "$release_json" ] || [ "$release_json" = "null" ]; then
        if [ "$is_beta" = "true" ]; then
            printf '%s\t%s\n' "0.0.0" "0.0.1-beta.1"
        else
            printf '%s\t%s\n' "0.0.0" "0.0.1"
        fi
        return
    fi

    printf '%s' "$release_json" | jq -r --arg is_beta "$is_beta" '
        def stable_version:
            if type == "array" then
                [ .[] | select(.tag_name? and (.tag_name | test("-beta\\.") | not)) | .tag_name ][0]
                    // "v0.0.0"
            else
                "v0.0.0"
            end
            | sub("^v"; "");

        def next_release($latest):
            ($latest | split(".") | map(tonumber? // 0)) as $parts
            | ($parts[0] // 0) as $major
            | ($parts[1] // 0) as $minor
            | ($parts[2] // 0) as $patch
            | ($patch + 1) as $next_patch
            | if $next_patch >= 10 then
                if ($minor + 1) >= 10 then
                    "\(($major + 1)).0.0"
                else
                    "\($major).\($minor + 1).0"
                end
              else
                "\($major).\($minor).\($next_patch)"
              end;

        def beta_max($prefix):
            [ .[]
              | select(.tag_name? and (.tag_name | startswith($prefix)))
              | .tag_name
              | ltrimstr($prefix)
              | try tonumber catch empty
            ] | if length > 0 then max else 0 end;

        (stable_version) as $base
        | (next_release($base)) as $next
        | if $is_beta == "true" then
            $base + "\t" + ($next + "-beta." + ((beta_max("v" + $next + "-beta.") + 1) | tostring))
          else
            $base + "\t" + $next
          end
    '
}

main() {
    section "參數檢查"

    require_env "GITEA_SERVER_URL" "${GITEA_SERVER_URL:-}"
    require_env "GITEA_REPOSITORY" "${GITEA_REPOSITORY:-}"

    if [ -n "${RUNNER_TOKEN:-}" ] && [ "${RUNNER_TOKEN:-}" != "null" ]; then
        info "RUNNER_TOKEN=***"
    else
        info "RUNNER_TOKEN=未提供"
    fi

    IS_BETA="$(normalize_beta_flag "${IS_BETA:-false}")"
    info "IS_BETA=$IS_BETA"

    section "取得版本資料"

    RELEASE_URL="$GITEA_SERVER_URL/api/v1/repos/$GITEA_REPOSITORY/releases"
    info "RELEASE_URL=$RELEASE_URL"

    if [ -n "${RUNNER_TOKEN:-}" ] && [ "${RUNNER_TOKEN:-}" != "null" ]; then
        info "使用授權 token 取得 release"
        RELEASE_JSON="$(curl -fsS -H "Authorization: token $RUNNER_TOKEN" "$RELEASE_URL")"
    else
        info "使用匿名請求取得 release"
        RELEASE_JSON="$(curl -fsS "$RELEASE_URL")"
    fi

    VERSION_INFO="$(calculate_version "$RELEASE_JSON" "$IS_BETA")"
    IFS=$'\t' read -r LATEST_TAG NEW_VERSION <<< "$VERSION_INFO"

    info "LATEST_VERSION=$LATEST_TAG"

    section "計算版本號"

    info "NEW_VERSION=$NEW_VERSION"
    write_output "$NEW_VERSION"
}

if [ "${BASH_SOURCE[0]}" = "$0" ]; then
    main "$@"
fi