#!/usr/bin/env bash
set -euo pipefail
# POS: communication matrix-sender — Send messages to a Matrix room via the client-server API (send, test, login)
# POS_SUBCMDS: send test login
# POS_CONFIG: matrix | matrix.env | MATRIX_HOMESERVER=:Homeserver URL (https://matrix.example.org)::https://matrix.example.org | MATRIX_ACCESS_TOKEN=secret:Access token (from 'pos communication matrix sender login' or a Matrix client) | MATRIX_USER_ID=:Your Matrix user id (set by login)::@you:example.org | MATRIX_ROOM_ID=:Room id or alias::#pos:example.org

CONFIG_DIR="${CONFIG_DIR:-${XDG_CONFIG_HOME:-$HOME/.config}/linux_post_install}"
CONFIG_FILE="$CONFIG_DIR/matrix.env"

# Shared config loader (canonical KEY=VALUE parser, env-wins precedence)
source "$(dirname "$0")/../lib/config-ui.sh" 2>/dev/null || source "$(dirname "$0")/config-ui.sh"

usage() {
    cat <<EOF
Usage: pos communication matrix sender [command] [args]

Send messages to a Matrix room via the client-server API (v3).

Commands:
  send <value> [options]   Send a text message to the configured room
  test                     Send a test message using the current config
  login --user <@id>       Get an access token (password prompt) and save it

Options (send):
  --markdown               Send with org.matrix.custom.html formatting
                           (best-effort markdown → HTML conversion)
  --room <id|alias>        Override the room for one send

Config:    $CONFIG_FILE (MATRIX_HOMESERVER, MATRIX_ACCESS_TOKEN,
           MATRIX_USER_ID, MATRIX_ROOM_ID) — edit it with 'pos config matrix'

Precedence: CLI flags > environment > config file.

Examples:
  pos communication matrix sender send "Backup finished"
  pos communication matrix sender send "**disk full**" --markdown
  pos communication matrix sender send "hello" --room '#ops:example.org'
  pos communication matrix sender login --user @you:example.org
  pos communication matrix sender test
EOF
    exit 0
}

err() { echo "ERROR: $*" >&2; exit 1; }
log() { echo "[+] $*"; }

load_config() {
    load_env_file "$CONFIG_FILE"
}

save_config() {
    mkdir -p "$CONFIG_DIR"
    local key="$1" val="$2" tmp
    tmp="$(mktemp)"
    grep -v "^${key}=" "$CONFIG_FILE" 2>/dev/null >"$tmp" || true
    printf '%s="%s"\n' "$key" "$val" >>"$tmp"
    mv "$tmp" "$CONFIG_FILE"
    chmod 600 "$CONFIG_FILE"
}

urlencode() {
    local s="$1"
    s="${s//#/%23}"
    s="${s//\"/%22}"
    s="${s// /%20}"
    printf '%s' "$s"
}

# Best-effort markdown → HTML for org.matrix.custom.html. Handles code
# fences, inline code, bold/italic/strike, links, headers, and lists. The
# conversion is deliberately simple — it must never fail the send.
md_to_html() {
    local t="$1"
    t="$(printf '%s' "$t" | sed -E \
        -e 's/&/\&amp;/g' \
        -e 's/</\&lt;/g' \
        -e 's/>/\&gt;/g' \
        -e 's/```([^`]*)```/\n<pre><code>\1<\/code><\/pre>\n/g' \
        -e 's/`([^`]*)`/<code>\1<\/code>/g' \
        -e 's/\*\*([^*]*)\*\*/<strong>\1<\/strong>/g' \
        -e 's/__([^_]*)__/<strong>\1<\/strong>/g' \
        -e 's/\*([^*]*)\*/<em>\1<\/em>/g' \
        -e 's/_([^_]*)_/<em>\1<\/em>/g' \
        -e 's/~~([^~]*)~~/<del>\1<\/del>/g' \
        -e 's/\[([^]]*)\]\(([^)]*)\)/<a href="\2">\1<\/a>/g' \
        -e 's/^[[:space:]]*#{1,6}[[:space:]]+/<h3>/' \
        -e 's/^[[:space:]]*([-*+]|[0-9]+\.)[[:space:]]+/<li>/' \
        -e 's/$/<br\/>/')"
    printf '%s' "$t"
}

api_base() {
    local base="${MATRIX_HOMESERVER:-}"
    [ -n "$base" ] || err "No homeserver — run 'pos config matrix' (MATRIX_HOMESERVER)"
    printf '%s' "${base%/}"
}

send_room_message() {
    local room="$1" text="$2" markdown="$3"
    [ -n "${MATRIX_ACCESS_TOKEN:-}" ] || err "No access token — run 'pos communication matrix sender login'"
    [ -n "$room" ] || err "No room — run 'pos config matrix' (MATRIX_ROOM_ID) or pass --room"
    local base txn body fmt
    base="$(api_base)"
    txn="$(date +%s%N)"
    room="$(urlencode "$room")"
    if [ "$markdown" -eq 1 ]; then
        fmt="$(md_to_html "$text")"
        body="$(jq -n --arg body "$text" --arg html "$fmt" \
            '{msgtype:"m.text", body:$body, format:"org.matrix.custom.html", formatted_body:$html}')"
    else
        body="$(jq -n --arg body "$text" '{msgtype:"m.text", body:$body}')"
    fi
    curl -fsS -m 60 -X PUT \
        -H "Authorization: Bearer ${MATRIX_ACCESS_TOKEN}" \
        -H "Content-Type: application/json" \
        --data "$body" \
        "${base}/_matrix/client/v3/rooms/${room}/send/m.room.message/${txn}" >/dev/null
}

cmd_send() {
    local value="" markdown=0 room="${MATRIX_ROOM_ID:-}"
    while [ $# -gt 0 ]; do
        case "$1" in
            --markdown) markdown=1; shift ;;
            --room)
                [ $# -ge 2 ] || err "--room needs a value"
                room="$2"; shift 2 ;;
            -h|--help) usage ;;
            --) shift; [ $# -ge 1 ] || err "No value given for send"; value="$1"; shift ;;
            -*) err "Unknown option '$1'" ;;
            *) [ -z "$value" ] || err "Unexpected extra argument '$1'"; value="$1"; shift ;;
        esac
    done
    [ -n "$value" ] || err "No value given for send"
    load_config
    [ -n "${room:-}" ] || room="${MATRIX_ROOM_ID:-}"
    send_room_message "$room" "$value" "$markdown"
    log "m.text sent to room ${room}"
}

cmd_login() {
    local user="" password
    while [ $# -gt 0 ]; do
        case "$1" in
            --user)
                [ $# -ge 2 ] || err "--user needs a value"
                user="$2"; shift 2 ;;
            -h|--help) usage ;;
            -*) err "Unknown option '$1'" ;;
            *) err "Unexpected argument '$1' (use --user @you:server)" ;;
        esac
    done
    [ -n "$user" ] || err "--user is required (e.g. --user @you:example.org)"
    [[ "$user" == @* ]] || user="@$user"
    load_config
    local base
    base="$(api_base)"
    read -rsp "Password for ${user}: " password </dev/tty || true
    echo >&2
    [ -n "$password" ] || err "empty password"
    local body code resp token uid
    body="$(mktemp)"
    code="$(curl -sS -o "$body" -w '%{http_code}' -m 60 -X POST \
        -H "Content-Type: application/json" \
        --data "$(jq -n --arg user "$user" --arg pw "$password" \
            '{type:"m.login.password", identifier:{type:"m.id.user", user:$user}, password:$pw, initial_device_display_name:"pos"}')" \
        "${base}/_matrix/client/v3/login")" || { rm -f "$body"; err "login request failed (homeserver unreachable?)"; }
    if [ "$code" != "200" ]; then
        local reason
        reason="$(jq -r 'if .errcode then .errcode + (if .error then ": " + .error else "" end) else "HTTP '"$code"'" end' "$body" 2>/dev/null || echo "HTTP $code")"
        rm -f "$body"
        err "login failed — $reason"
    fi
    resp="$(cat "$body")"
    rm -f "$body"
    token="$(printf '%s' "$resp" | jq -r '.access_token // empty')"
    uid="$(printf '%s' "$resp" | jq -r '.user_id // empty')"
    [ -n "$token" ] || err "login succeeded but no access_token in response"
    [ -n "$uid" ] || uid="$user"
    save_config MATRIX_ACCESS_TOKEN "$token"
    save_config MATRIX_USER_ID "$uid"
    log "logged in as $uid — token saved to $CONFIG_FILE"
}

cmd_test() {
    load_config
    send_room_message "${MATRIX_ROOM_ID:-}" "Test message from pos $(date '+%Y-%m-%d %H:%M:%S')" 0
    log "test message sent to room ${MATRIX_ROOM_ID:-}"
}

cmd="${1:-}"

case "$cmd" in
    -h|--help) usage ;;
    send)
        shift
        cmd_send "$@"
        ;;
    test)
        shift
        cmd_test "$@"
        ;;
    login)
        shift
        cmd_login "$@"
        ;;
    "")
        usage
        ;;
    *)
        echo "ERROR: Unknown matrix command '$cmd'"
        echo "Run 'pos communication matrix-sender --help' for usage."
        exit 1
        ;;
esac