gl

#!/usr/bin/env bash

set -euo pipefail

usage() {
    cat <<'EOF'
Usage:
  gl doctor
  gl api get [--raw] <gitlab-web-url> [api-sub-resource]
  gl api mr <mr-url>
  gl git ro clone <repo-url> [directory]
  gl git ro fetch [args...]
  gl git ro pull [args...]
  gl git ro ls-remote [args...]
  gl git ro remote update [args...]
  gl git rw push [args...]
EOF
}

die() {
    printf '%s\n' "$*" >&2
    exit 1
}

need_cmd() {
    command -v "$1" >/dev/null 2>&1 || die "Required command not found: $1"
}

require_env_nonempty() {
    local name="$1"
    [[ -n "${!name:-}" ]] || die "$name is not set."
}

ensure_clean_git_url() {
    local url="$1"
    [[ "$url" =~ ^https?://[^/]+/.+\.git/?$ ]] || die "Expected an HTTPS GitLab repository URL ending in .git."
    [[ ! "$url" =~ ^https?://[^/]*@ ]] || die "Repository URL must not contain embedded credentials."
}

ensure_gitlab_web_url() {
    local url="$1"
    [[ "$url" =~ ^https?://[^/]+/.+ ]] || die "Expected a GitLab web URL."
}

build_api_url() {
    local web_url="$1"
    local sub_resource="${2:-}"
    local without_protocol host path project_path resource_tail encoded_project api_url

    ensure_gitlab_web_url "$web_url"

    without_protocol="${web_url#https://}"
    without_protocol="${without_protocol#http://}"
    [[ "$without_protocol" == */* ]] || die "Expected a GitLab web URL."

    host="${without_protocol%%/*}"
    path="${without_protocol#*/}"

    [[ -n "$host" && -n "$path" && "$path" != "$without_protocol" ]] || die "Expected a GitLab web URL."

    if [[ "$path" == *"/-/"* ]]; then
        project_path="${path%%/-/*}"
        resource_tail="${path#*/-/}"
    else
        project_path="$path"
        resource_tail=""
    fi

    [[ -n "$project_path" ]] || die "Could not determine the project path from the URL."

    encoded_project="${project_path//\//%2F}"
    api_url="https://${host}/api/v4/projects/${encoded_project}"

    if [[ -n "$resource_tail" ]]; then
        api_url="${api_url}/${resource_tail}"
    fi

    if [[ -n "$sub_resource" ]]; then
        api_url="${api_url}/${sub_resource}"
    fi

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

api_request_raw() {
    local web_url="$1"
    local sub_resource="${2:-}"
    local api_url

    need_cmd curl
    require_env_nonempty GITLAB_BOT_READ_TOKEN
    api_url="$(build_api_url "$web_url" "$sub_resource")"
    curl -fsS -k --header "PRIVATE-TOKEN: $GITLAB_BOT_READ_TOKEN" "$api_url"
}

api_request_pretty() {
    local web_url="$1"
    local sub_resource="${2:-}"

    need_cmd jq
    api_request_raw "$web_url" "$sub_resource" | jq .
}

api_request_paginated_array() {
    need_cmd jq

    local web_url="$1"
    local sub_resource_base="$2"
    local page=1
    local merged='[]'
    local page_json page_count page_resource

    while :; do
        page_resource="${sub_resource_base}?page=${page}&per_page=100"
        page_json="$(api_request_raw "$web_url" "$page_resource")"
        page_count="$(printf '%s' "$page_json" | jq 'if type == "array" then length else 0 end')"

        if [[ "$page_count" == "0" ]]; then
            break
        fi

        merged="$(jq -sc '.[0] + .[1]' <(printf '%s' "$merged") <(printf '%s' "$page_json"))"
        page=$((page + 1))
    done

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

extract_api_error() {
    jq -er '
        if type == "object" and (.error or .message) then
            .error // .message |
            if type == "array" then join(", ") else tostring end
        else
            empty
        end
    ' 2>/dev/null || true
}

run_git_with_token() {
    local token_var="$1"
    shift

    local askpass_script status
    askpass_script="$(mktemp)"

    cat >"$askpass_script" <<'EOF'
#!/usr/bin/env bash
case "${1:-}" in
    *Username*)
        printf '%s\n' "${GL_GIT_HTTP_USERNAME:-oauth2}"
        ;;
    *Password*)
        printf '%s\n' "${GL_GITLAB_TOKEN:-}"
        ;;
    *)
        exit 1
        ;;
esac
EOF
    chmod 700 "$askpass_script"

    set +e
    GL_GITLAB_TOKEN="${!token_var}" \
    GL_GIT_HTTP_USERNAME="oauth2" \
    GIT_TERMINAL_PROMPT=0 \
    GIT_ASKPASS="$askpass_script" \
    git "$@"
    status=$?
    set -e

    rm -f "$askpass_script"
    return "$status"
}

cmd_api_get() {
    local raw=false

    if [[ "${1:-}" == "--raw" ]]; then
        raw=true
        shift
    fi

    [[ -n "${1:-}" ]] || die "Usage: gl api get [--raw] <gitlab-web-url> [api-sub-resource]"

    local web_url="$1"
    local sub_resource="${2:-}"

    if $raw; then
        api_request_raw "$web_url" "$sub_resource"
    else
        api_request_pretty "$web_url" "$sub_resource"
    fi
}

cmd_api_mr() {
    need_cmd jq

    local mr_url="${1:-}"
    [[ -n "$mr_url" ]] || die "Usage: gl api mr <mr-url>"

    if [[ ! "$mr_url" =~ ^(https?://[^/]+)/(.+)/-/merge_requests/([0-9]+)$ ]]; then
        die "Expected a GitLab merge request URL."
    fi

    local base_url project_path mr_iid
    base_url="${BASH_REMATCH[1]}"
    project_path="${BASH_REMATCH[2]}"
    mr_iid="${BASH_REMATCH[3]}"

    local mr_json error_message
    mr_json="$(api_request_raw "$mr_url")"
    error_message="$(printf '%s' "$mr_json" | extract_api_error)"

    [[ -z "$error_message" ]] || die "Error fetching merge request: $error_message"

    local mr_title mr_description mr_state mr_author mr_source_branch mr_target_branch mr_web_url
    mr_title="$(printf '%s' "$mr_json" | jq -r '.title // "No title"')"
    mr_description="$(printf '%s' "$mr_json" | jq -r '.description // "No description"')"
    mr_state="$(printf '%s' "$mr_json" | jq -r '.state // "unknown"')"
    mr_author="$(printf '%s' "$mr_json" | jq -r '.author.name // .author.username // "unknown"')"
    mr_source_branch="$(printf '%s' "$mr_json" | jq -r '.source_branch // "unknown"')"
    mr_target_branch="$(printf '%s' "$mr_json" | jq -r '.target_branch // "unknown"')"
    mr_web_url="$(printf '%s' "$mr_json" | jq -r '.web_url // ""')"

    printf '========================================\n'
    printf 'Merge Request: %s!%s\n' "$project_path" "$mr_iid"
    printf '========================================\n\n'
    printf 'TITLE: %s\n' "$mr_title"
    printf 'STATE: %s\n' "$mr_state"
    printf 'AUTHOR: %s\n' "$mr_author"
    printf 'BRANCHES: %s -> %s\n' "$mr_source_branch" "$mr_target_branch"
    printf 'URL: %s\n\n' "$mr_web_url"
    printf 'DESCRIPTION:\n'
    printf '%s\n' '----------------------------------------'
    printf '%s\n' "$mr_description"
    printf '%s\n\n' '----------------------------------------'
    printf 'LINKED ISSUES:\n'
    printf '%s\n' '----------------------------------------'

    local linked_issues=""
    local issue_numbers issue_urls
    issue_numbers="$(printf '%s\n' "$mr_description" | grep -oEi '(closes?|fixes?|resolves?|related to)\s*#([0-9]+)' | grep -oE '[0-9]+' || true)"
    issue_urls="$(printf '%s\n' "$mr_description" | grep -oE "${base_url}/[^[:space:]]*/issues/[0-9]+" || true)"

    local issue_num constructed_issue_url issue_json issue_title issue_state issue_web_url issue_url issue_project_path normalized_issue_url

    if [[ -n "$issue_numbers" ]]; then
        for issue_num in $issue_numbers; do
            constructed_issue_url="${base_url}/${project_path}/-/issues/${issue_num}"
            issue_json="$(api_request_raw "$constructed_issue_url" 2>/dev/null || printf '{}')"
            issue_title="$(printf '%s' "$issue_json" | jq -r '.title // empty')"
            if [[ -n "$issue_title" ]]; then
                issue_state="$(printf '%s' "$issue_json" | jq -r '.state // "unknown"')"
                issue_web_url="$(printf '%s' "$issue_json" | jq -r '.web_url // ""')"
                printf '  #%s: %s [%s]\n' "$issue_num" "$issue_title" "$issue_state"
                printf '    %s\n' "$issue_web_url"
                linked_issues="found"
            fi
        done
    fi

    if [[ -n "$issue_urls" ]]; then
        for issue_url in $issue_urls; do
            if [[ "$issue_url" =~ ${base_url}/(.+)/issues/([0-9]+)$ ]]; then
                issue_project_path="${BASH_REMATCH[1]}"
                issue_num="${BASH_REMATCH[2]}"
                issue_project_path="${issue_project_path%/-}"
                normalized_issue_url="${base_url}/${issue_project_path}/-/issues/${issue_num}"
                issue_json="$(api_request_raw "$normalized_issue_url" 2>/dev/null || printf '{}')"
                issue_title="$(printf '%s' "$issue_json" | jq -r '.title // empty')"
                if [[ -n "$issue_title" ]]; then
                    issue_state="$(printf '%s' "$issue_json" | jq -r '.state // "unknown"')"
                    printf '  %s#%s: %s [%s]\n' "$issue_project_path" "$issue_num" "$issue_title" "$issue_state"
                    printf '    %s\n' "$issue_url"
                    linked_issues="found"
                fi
            fi
        done
    fi

    if [[ -z "$linked_issues" ]]; then
        printf '  No linked issues found in description.\n'
    fi

    printf '\nCOMMENTS:\n'
    printf '%s\n' '----------------------------------------'

    local discussions_json comment_output
    discussions_json="$(api_request_paginated_array "$mr_url" "discussions")"
    comment_output="$(
        printf '%s' "$discussions_json" | jq -r '
            [
                .[]
                | (.notes // [])[]
                | select(.system | not)
                | {
                    created_at: (.created_at // ""),
                    author_name: (.author.name // .author.username // "unknown"),
                    body: (.body // "")
                }
            ]
            | sort_by(.created_at)
            | .[]
            | "[\(.created_at | split("T")[0])] \(.author_name):\n\(.body)\n"
        '
    )"

    if [[ -z "$comment_output" ]]; then
        printf '  No comments on this merge request.\n'
    else
        printf '%s' "$comment_output"
    fi

    printf '========================================\n'
    printf 'End of MR %s!%s\n' "$project_path" "$mr_iid"
    printf '========================================\n'
}

cmd_git_ro() {
    require_env_nonempty GITLAB_BOT_READ_TOKEN

    local verb="${1:-}"
    [[ -n "$verb" ]] || die "Usage: gl git ro <clone|fetch|pull|ls-remote|remote update> [args...]"
    shift || true

    case "$verb" in
        clone)
            local repo_url="${1:-}"
            [[ -n "$repo_url" ]] || die "Usage: gl git ro clone <repo-url> [directory]"
            ensure_clean_git_url "$repo_url"
            run_git_with_token GITLAB_BOT_READ_TOKEN clone "$@"
            ;;
        fetch|pull|ls-remote)
            run_git_with_token GITLAB_BOT_READ_TOKEN "$verb" "$@"
            ;;
        remote)
            [[ "${1:-}" == "update" ]] || die "Only 'gl git ro remote update' is supported."
            run_git_with_token GITLAB_BOT_READ_TOKEN "$verb" "$@"
            ;;
        push)
            die "Push is not allowed in read-only mode."
            ;;
        *)
            die "Unsupported read-only git command: $verb"
            ;;
    esac
}

cmd_git_rw() {
    require_env_nonempty GITLAB_WRITE_TOKEN

    local verb="${1:-}"
    [[ -n "$verb" ]] || die "Usage: gl git rw push [args...]"
    shift || true

    case "$verb" in
        push)
            run_git_with_token GITLAB_WRITE_TOKEN push "$@"
            ;;
        *)
            die "Unsupported write-capable git command: $verb"
            ;;
    esac
}

cmd_api() {
    local action="${1:-}"
    shift || true

    case "$action" in
        get)
            cmd_api_get "$@"
            ;;
        mr)
            cmd_api_mr "$@"
            ;;
        *)
            die "Usage: gl api <get|mr> ..."
            ;;
    esac
}

cmd_doctor() {
    local read_token_state="empty"
    local write_token_state="empty"
    command -v curl >/dev/null 2>&1 && printf 'curl: ok\n' || printf 'curl: missing\n'
    command -v jq >/dev/null 2>&1 && printf 'jq: ok\n' || printf 'jq: missing\n'
    command -v git >/dev/null 2>&1 && printf 'git: ok\n' || printf 'git: missing\n'

    [[ -n "${GITLAB_BOT_READ_TOKEN:-}" ]] && read_token_state="set"
    [[ -n "${GITLAB_WRITE_TOKEN:-}" ]] && write_token_state="set"

    printf 'GITLAB_BOT_READ_TOKEN: %s\n' "$read_token_state"
    printf 'GITLAB_WRITE_TOKEN: %s\n' "$write_token_state"

    printf 'api_get: gl api get [--raw] <gitlab-web-url> [api-sub-resource]\n'
    printf 'api_mr: gl api mr <mr-url>\n'
    printf 'git_ro: gl git ro <clone|fetch|pull|ls-remote|remote update>\n'
    printf 'git_rw: gl git rw push [args...]\n'
}

cmd_git() {
    local mode="${1:-}"
    shift || true

    case "$mode" in
        ro)
            cmd_git_ro "$@"
            ;;
        rw)
            cmd_git_rw "$@"
            ;;
        *)
            die "Usage: gl git <ro|rw> ..."
            ;;
    esac
}

main() {
    local command="${1:-}"
    shift || true

    case "$command" in
        doctor)
            cmd_doctor
            ;;
        api)
            cmd_api "$@"
            ;;
        git)
            cmd_git "$@"
            ;;
        ""|help|--help|-h)
            usage
            ;;
        *)
            die "Usage: gl <doctor|api|git> ..."
            ;;
    esac
}

main "$@"