"""ACDL Terraform adapter — compile a Target Stack instance to Terraform.

ARCHITECTURE.md §12.2: the adapter translates the stack-typed L1 interface
to a Terraform variable/output block, the L2 composition tree to a
root module that calls the L1 modules, the stack-typed relationships to
Terraform module references, and emits a Terraform plan from the stack.

The adapter is a THIN LAYER; it does not own L1/L2 content — it only
translates. Substrate-agnostic in, Terraform out.

Phase 09 spike: handled one L1 (s3, stack type aws:s3:bucket).
Phase 13: generalized the resource/output emission via TYPE_MAP +
INPUT_MAP + OUTPUT_MAP tables; added ECS Fargate stack types. S3 behavior
is preserved (regression baseline: modules/l1/s3/instance.json).

CLI: adapter.py <instance.json> <out_dir>
"""

import json
import os
import sys


# Stack type -> Terraform resource type. The only substrate-specific table.
# As more L1s land, this grows; the L1 content + stack do not change.
TYPE_MAP = {
    "aws:s3:bucket": "aws_s3_bucket",
    "aws:ec2:vpc": "aws_vpc",
    "aws:ec2:subnet": "aws_subnet",
    "aws:ec2:routetable": "aws_route_table",
    "aws:ecs:cluster": "aws_ecs_cluster",
    "aws:ecs:task_definition": "aws_ecs_task_definition",
    "aws:ecs:service": "aws_ecs_service",
    "aws:iam:role": "aws_iam_role",
    "aws:elbv2:loadbalancer": "aws_lb",
    "aws:elbv2:listener": "aws_lb_listener",
    "aws:elbv2:targetgroup": "aws_lb_target_group",
    "aws:ecr:repository": "aws_ecr_repository",
}

# Stack input name -> Terraform arg name, per stack type. Only non-identity
# mappings are listed; any input not present here uses the stack name as
# the Terraform arg name (identity).
INPUT_MAP = {
    "aws:s3:bucket": {"bucket_name": "bucket"},
    "aws:ec2:vpc": {"cidr": "cidr_block", "name": "_tag_name"},
    "aws:ec2:subnet": {"cidr": "cidr_block", "az": "availability_zone", "name": "_tag_name", "vpc_id": "vpc_id"},
    "aws:ec2:routetable": {"vpc_id": "vpc_id", "name": "_tag_name"},
    "aws:ecs:cluster": {},
    "aws:ecs:task_definition": {},
    "aws:ecs:service": {"security_group": "security_groups", "subnets": "subnets", "cluster_arn": "cluster"},
    "aws:iam:role": {"role_name": "name", "assume_role_policy": "assume_role_policy"},
    "aws:elbv2:loadbalancer": {"subnets": "subnets", "security_group": "security_groups"},
    "aws:elbv2:listener": {},
    "aws:elbv2:targetgroup": {"port": "port", "protocol": "protocol"},
    "aws:ecr:repository": {},
}

# Stack output name -> Terraform attribute name, per stack type. Only
# non-identity mappings are listed; any output not present here uses the
# stack name as the Terraform attribute name (identity).
OUTPUT_MAP = {
    "aws:s3:bucket": {"bucket_arn": "arn", "bucket_name": "id"},
    "aws:ec2:vpc": {"vpc_id": "id"},
    "aws:ec2:subnet": {"subnet_id": "id"},
    "aws:ec2:routetable": {},
    "aws:ecs:cluster": {"cluster_arn": "arn", "cluster_id": "id"},
    "aws:ecs:task_definition": {"task_def_arn": "arn"},
    "aws:ecs:service": {"service_arn": "id"},
    "aws:iam:role": {"role_arn": "arn", "role_id": "id"},
    "aws:elbv2:loadbalancer": {"lb_arn": "id"},
    "aws:elbv2:listener": {"listener_arn": "id"},
    "aws:elbv2:targetgroup": {"target_group_arn": "arn"},
    "aws:ecr:repository": {"repository_arn": "arn"},
}


def _tf_value(value):
    """Render a Python value as a Terraform expression fragment."""
    if isinstance(value, bool):
        return "true" if value else "false"
    if isinstance(value, (int, float)) and not isinstance(value, bool):
        return str(value)
    if isinstance(value, str):
        if value.startswith("ref:"):
            raise ValueError("ref: values must be resolved via _ref_expr, not _tf_value")
        # Detect a JSON string (object/array) and emit jsonencode() so inner
        # quotes don't break HCL. Plain strings stay double-quoted.
        stripped = value.lstrip()
        if stripped and stripped[0] in "{[" :
            try:
                parsed = json.loads(value)
                if isinstance(parsed, (dict, list)):
                    return f"jsonencode({json.dumps(parsed, sort_keys=True)})"
            except json.JSONDecodeError:
                pass
        return f'"{value}"'
    if isinstance(value, (dict, list)):
        return f"jsonencode({json.dumps(value, sort_keys=True)})"
    raise ValueError(f"unsupported input value type {type(value).__name__}")


def _ref_expr(ref_value, type_by_id):
    """Translate a "ref:<stack_resource_id>.<output>" string to a Terraform
    interpolation "${<tf_type>.<id>.<attr>}".

    <stack_resource_id> is the stack resource id of the producing resource;
    <output> is the per-resource output name (e.g. `subnet_id`,
    `cluster_arn`); the attribute is mapped through OUTPUT_MAP for the
    referenced resource's stack type. The resolver emits the ref using the
    stack resource id directly (not the child id), so no child->resource
    lookup table is needed here.
    """
    body = ref_value[len("ref:"):]
    rid, out_name = body.split(".", 1)
    rtype = type_by_id.get(rid)
    if not rtype:
        raise ValueError(f"ref to unknown stack resource id {rid!r}")
    tf_type = TYPE_MAP.get(rtype)
    if not tf_type:
        raise ValueError(f"ref target {rid!r} has unknown stack type {rtype!r}")
    out_map = OUTPUT_MAP.get(rtype, {})
    tf_attr = out_map.get(out_name, out_name)
    return f"{tf_type}.{rid}.{tf_attr}"


def _value_expr(value, type_by_id=None):
    """Render a value as a Terraform expression fragment. A "ref:<id>.<output>"
    string becomes a Terraform interpolation; other values use _tf_value."""
    if isinstance(value, str) and value.startswith("ref:"):
        if type_by_id is None:
            raise ValueError("ref: value encountered without a type_by_id table")
        return _ref_expr(value, type_by_id)
    return _tf_value(value)


def _emit_resource(resource, type_by_id=None):
    rtype = resource["type"]
    rid = resource["id"]
    tf_type = TYPE_MAP.get(rtype)
    if not tf_type:
        raise ValueError(f"unknown stack type {rtype!r} (adapter TYPE_MAP has no entry)")
    in_map = INPUT_MAP.get(rtype, {})
    body = []
    inputs = resource.get("inputs", {})
    for in_name, value in inputs.items():
        if in_name == "region":
            continue
        arg = in_map.get(in_name, in_name)
        if arg == "_tag_name":
            if isinstance(value, str) and not value.startswith("ref:"):
                tag_name = value
            else:
                tag_name = "app"
            continue
        if rtype == "aws:ecs:task_definition" and in_name in ("image", "port", "env"):
            continue
        if rtype == "aws:iam:role" and in_name == "managed_policies":
            continue
        if rtype == "aws:elbv2:loadbalancer" and in_name == "subnets":
            if isinstance(value, str) and value.startswith("ref:"):
                body.append(f"subnets = [{_ref_expr(value, type_by_id)}]")
            else:
                body.append(f"subnets = [{value}]" if isinstance(value, str) else f"subnets = {_tf_value(value)}")
            continue
        if rtype == "aws:elbv2:loadbalancer" and in_name == "security_group":
            if isinstance(value, str) and value.startswith("ref:"):
                body.append(f"security_groups = [{_ref_expr(value, type_by_id)}]")
            else:
                body.append(f"security_groups = [{value}]" if isinstance(value, str) else f"security_groups = {_tf_value(value)}")
            continue
        if rtype == "aws:ec2:routetable" and in_name == "igw_id":
            continue
        if rtype == "aws:ecs:service" and in_name == "lb_target_group_arn":
            if isinstance(value, str) and value.startswith("ref:"):
                tg_arn = _ref_expr(value, type_by_id)
            else:
                tg_arn = _tf_value(value)
            body.append("load_balancer {")
            body.append(f"  target_group_arn = {tg_arn}")
            body.append("  container_name = \"app\"")
            body.append("  container_port = 8080")
            body.append("}")
            continue
        if rtype == "aws:ecs:service" and in_name in ("subnets", "security_group"):
            # Collected into network_configuration block (emitted after all inputs).
            continue
        body.append(f"{arg} = {_value_expr(value, type_by_id)}")
    if rtype == "aws:ecs:service":
        subnets_val = inputs.get("subnets")
        sg_val = inputs.get("security_group")
        body.append("network_configuration {")
        body.append("  subnets = " + (
            f"[{_ref_expr(subnets_val, type_by_id)}]" if isinstance(subnets_val, str) and subnets_val.startswith("ref:")
            else _tf_value([subnets_val] if isinstance(subnets_val, str) else subnets_val or [])
        ))
        body.append("  security_groups = " + (
            f"[{_ref_expr(sg_val, type_by_id)}]" if isinstance(sg_val, str) and sg_val.startswith("ref:")
            else _tf_value([sg_val] if isinstance(sg_val, str) else sg_val or [])
        ))
        body.append("}")
        body.append("desired_count = 1")
        body.append("launch_type = \"FARGATE\"")
        body.append("task_definition = aws_ecs_task_definition.service-taskdefinition.arn")
        body.append("name = \"acdl-microservice\"")
    nfrs = resource.get("nfrs", {})
    if isinstance(nfrs, dict) and "versioning" in nfrs and rtype == "aws:s3:bucket":
        versioning = nfrs.get("versioning", True)
        body.append("versioning {")
        body.append(f'  enabled = {"true" if versioning else "false"}')
        body.append("}")
    elif rtype == "aws:s3:bucket":
        body.append("versioning {")
        body.append("  enabled = true")
        body.append("}")
    if rtype == "aws:ecs:task_definition":
        body.append(_container_definitions(inputs))
        family = inputs.get("family", "app")
        body.append(f'family = "{family}"')
    if rtype in ("aws:ec2:vpc", "aws:ec2:subnet") and "_tag_name" in in_map.values():
        tag_name = inputs.get("name", "acdl")
        if isinstance(tag_name, str) and not tag_name.startswith("ref:"):
            body.append("tags = {")
            body.append(f'  Name = "{tag_name}"')
            body.append("}")
    if rtype == "aws:iam:role" and "managed_policies" in inputs:
        arns = [a.strip() for a in str(inputs["managed_policies"]).split(",") if a.strip()]
        body.append("managed_policy_arns = [" + ", ".join(f'"{a}"' for a in arns) + "]")
    if rtype == "aws:elbv2:listener":
        body.append("default_action {")
        body.append("  type = \"forward\"")
        body.append("  target_group_arn = aws_lb_target_group.alb-targetgroup.arn")
        body.append("}")
        body.append("load_balancer_arn = aws_lb.alb-loadbalancer.id")
    if rtype == "aws:elbv2:loadbalancer":
        body.append("load_balancer_type = \"application\"")
    if rtype == "aws:elbv2:targetgroup":
        body.append("target_type = \"ip\"")
        body.append("vpc_id = aws_vpc.vpc-vpc.id")
        body.append("protocol = \"HTTP\"")
    if rtype == "aws:ec2:routetable":
        body.append("route {")
        body.append("  cidr_block = \"0.0.0.0/0\"")
        body.append("  gateway_id = aws_internet_gateway.vpc-igw.id")
        body.append("}")
        body.append("tags = {")
        body.append('  Name = "acdl-microservice-rt"')
        body.append("}")
    return _resource_block(rid, tf_type, body)


def _emit_igw(resources):
    """Emit an internet gateway + route table associations for the VPC."""
    vpc_id = next((r["id"] for r in resources if r["type"] == "aws:ec2:vpc"), "vpc-vpc")
    subnet_id = next((r["id"] for r in resources if r["type"] == "aws:ec2:subnet"), "vpc-subnet")
    rt_id = next((r["id"] for r in resources if r["type"] == "aws:ec2:routetable"), "vpc-routetable")
    parts = []
    parts.append(_resource_block("vpc-igw", "aws_internet_gateway", [
        f"vpc_id = aws_vpc.{vpc_id}.id",
        "tags = {",
        '  Name = "acdl-microservice-igw"',
        "}",
    ]))
    parts.append(_resource_block("vpc-rta", "aws_route_table_association", [
        f"subnet_id = aws_subnet.{subnet_id}.id",
        f"route_table_id = aws_route_table.{rt_id}.id",
    ]))
    return "\n".join(parts)


def _container_definitions(inputs):
    image = inputs.get("image", "")
    port = inputs.get("port", 80)
    env_raw = inputs.get("env")
    environment = []
    if isinstance(env_raw, dict):
        for k, v in env_raw.items():
            environment.append({"name": k, "value": str(v)})
    elif isinstance(env_raw, str) and env_raw:
        try:
            parsed = json.loads(env_raw)
            if isinstance(parsed, dict):
                for k, v in parsed.items():
                    environment.append({"name": k, "value": str(v)})
        except json.JSONDecodeError:
            pass
    container = {
        "name": "app",
        "image": image,
        "essential": True,
        "portMappings": [{"containerPort": port}],
    }
    if environment:
        container["environment"] = environment
    return "container_definitions = " + _tf_value([container])


def _resource_block(rid, tf_type, body):
    """Emit a top-level resource block."""
    head = f'resource "{tf_type}" "{rid}" {{'
    body_str = "\n".join(f"  {l}" for l in body)
    return f"{head}\n{body_str}\n}}\n"


def _emit_output(output_name, value_expr):
    return f'output "{output_name}" {{\n  value = {value_expr}\n}}\n'


def adapt(stack_instance, out_dir):
    """Emit main.tf + terraform.tf + providers.tf to out_dir for the stack instance."""
    os.makedirs(out_dir, exist_ok=True)
    stack = stack_instance["stack"]
    resources = stack_instance["resources"]

    # --- providers.tf: aws provider, region from the first resource's inputs.region ---
    region = "us-east-1"
    for r in resources:
        if "region" in r.get("inputs", {}):
            region = r["inputs"]["region"]
            break
    providers_tf = (
        f'provider "aws" {{\n'
        f'  region = "{region}"\n'
        f'}}\n'
    )

    # --- terraform.tf: required_version + required_providers + S3 backend (no DynamoDB lock per D-P09-1) ---
    # The backend key is derived from the stack name so l1 vs l2 spikes use separate state keys (D-P10-1).
    stack_name = stack.get("name", "spike")
    terraform_tf = (
        'terraform {\n'
        '  required_version = ">= 1.9, < 1.10"\n'
        '  required_providers {\n'
        '    aws = {\n'
        '      source  = "hashicorp/aws"\n'
        '      version = "~> 5.0"\n'
        '    }\n'
        '  }\n'
        '  backend "s3" {\n'
        '    bucket = "acdl-tfstate-581513795199-us-east-1"\n'
        f'    key    = "spike/{stack_name}/terraform.tfstate"\n'
        '    region = "us-east-1"\n'
        '  }\n'
        '}\n'
    )

    # --- main.tf: resources + outputs ---
    # Build a stack-resource-id -> stack-type table so `ref:` input values can
    # be resolved to Terraform interpolations without a child->resource
    # lookup (the resolver emits refs with the stack resource id directly).
    type_by_id = {r["id"]: r["type"] for r in resources}
    main_tf_parts = []
    has_vpc = any(r["type"] == "aws:ec2:vpc" for r in resources)
    for r in resources:
        main_tf_parts.append(_emit_resource(r, type_by_id))
        rid = r["id"]
        rtype = r["type"]
        tf_type = TYPE_MAP.get(rtype)
        out_map = OUTPUT_MAP.get(rtype, {})
        outputs = r.get("outputs", {})
        for out_name in outputs:
            tf_attr = out_map.get(out_name, out_name)
            main_tf_parts.append(_emit_output(out_name, f"{tf_type}.{rid}.{tf_attr}"))
    if has_vpc:
        main_tf_parts.append(_emit_igw(resources))
    main_tf = "\n".join(main_tf_parts)

    with open(os.path.join(out_dir, "main.tf"), "w") as fh:
        fh.write(main_tf)
    with open(os.path.join(out_dir, "terraform.tf"), "w") as fh:
        fh.write(terraform_tf)
    with open(os.path.join(out_dir, "providers.tf"), "w") as fh:
        fh.write(providers_tf)
    return out_dir


if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("usage: adapter.py <instance.json> <out_dir>", file=sys.stderr)
        sys.exit(2)
    with open(sys.argv[1], "r") as fh:
        stack = json.load(fh)
    adapt(stack, sys.argv[2])
    print(f"adapter: emitted terraform to {sys.argv[2]}", file=sys.stderr)