#!/usr/bin/env nu
# Derived variables for loki bundle rendering.
# Generates loki_config_yaml from params.storage_backend and params.retention_days.

def main [component_json: string]: nothing -> nothing {
    let d = ($component_json | from json)

    let backend     = ($d | get -o params.storage_backend.kind     | default "filesystem")
    let bucket      = ($d | get -o params.storage_backend.bucket   | default "loki-chunks")
    let region      = ($d | get -o params.storage_backend.region   | default "us-east-1")
    let endpoint    = ($d | get -o params.storage_backend.endpoint | default "")
    # insecure=true disables HTTPS on the S3 connection (plain HTTP). Required for
    # in-cluster object stores served over HTTP (e.g. Garage at garage.svc:3900,
    # TLS terminated at the ingress, not the store). Defaults false for real AWS/HTTPS.
    let insecure    = ($d | get -o params.storage_backend.insecure | default false)
    let retention   = ($d | get -o params.retention_days           | default 90)
    let replication = ($d | get -o params.replication              | default 1)

    # Resolve S3 endpoint: use explicit endpoint if set, fall back to AWS regional URL.
    let s3_endpoint = if ($endpoint | is-not-empty) { $endpoint } else { $"s3.($region).amazonaws.com" }

    let object_store = if $backend == "s3" { "s3" } else { "filesystem" }
    let delete_store = if $backend == "s3" { "s3" } else { "filesystem" }

    # Loki 3.x: S3 config lives under common.storage.s3.
    # filesystem fallback uses common.storage.filesystem paths only.
    let common_storage = if $backend == "s3" {
$"  storage:
    s3:
      endpoint: ($s3_endpoint)
      region: ($region)
      bucketnames: ($bucket)
      access_key_id: $\{LOKI_S3_ACCESS_KEY}
      secret_access_key: $\{LOKI_S3_SECRET_KEY}
      insecure: ($insecure)
      s3forcepathstyle: true
      http_config:
        idle_conn_timeout: 90s
        insecure_skip_verify: false"
    } else {
$"  storage:
    filesystem:
      chunks_directory: /loki/chunks
      rules_directory: /loki/rules"
    }

    let loki_config_yaml = $"auth_enabled: false

server:
  http_listen_port: 3100
  grpc_listen_port: 9096

common:
  instance_addr: 127.0.0.1
  path_prefix: /loki
($common_storage)
  replication_factor: ($replication)
  ring:
    kvstore:
      store: inmemory

query_range:
  results_cache:
    cache:
      embedded_cache:
        enabled: true
        max_size_mb: 100

schema_config:
  configs:
    - from: 2024-01-01
      store: tsdb
      object_store: ($object_store)
      schema: v13
      index:
        prefix: index_
        period: 24h

storage_config:
  tsdb_shipper:
    active_index_directory: /loki/index
    cache_location: /loki/index_cache
    cache_ttl: 24h

ruler:
  alertmanager_url: http://localhost:9093

limits_config:
  retention_period: ($retention)d

compactor:
  working_directory: /loki/compactor
  retention_enabled: true
  retention_delete_delay: 2h
  retention_delete_worker_count: 150
  delete_request_store: ($delete_store)

analytics:
  reporting_enabled: false"

    { loki_config_yaml: $loki_config_yaml } | to json --raw | print
}