"""Provider block generator for Terraform HCL output.

Generates a providers.tf file containing:
- A terraform { required_providers { ... } } block listing all providers used
- Individual provider configuration blocks with platform-specific settings
  (endpoints, certificates, credentials) for each distinct provider type.
"""

from __future__ import annotations

from iac_reverse.models import ProviderType, ScanProfile, GeneratedFile


# ---------------------------------------------------------------------------
# Provider metadata: maps ProviderType to Terraform provider details
# ---------------------------------------------------------------------------

# Each entry: (terraform_provider_name, source, version_constraint)
_PROVIDER_METADATA: dict[ProviderType, tuple[str, str, str]] = {
    ProviderType.KUBERNETES: (
        "kubernetes",
        "hashicorp/kubernetes",
        "~> 2.0",
    ),
    ProviderType.DOCKER_SWARM: (
        "docker",
        "kreuzwerker/docker",
        "~> 3.0",
    ),
    ProviderType.SYNOLOGY: (
        "synology",
        "synology-community/synology",
        "~> 0.2",
    ),
    ProviderType.HARVESTER: (
        "harvester",
        "harvester/harvester",
        "~> 0.6",
    ),
    ProviderType.BARE_METAL: (
        "redfish",
        "dell/redfish",
        "~> 1.0",
    ),
    ProviderType.WINDOWS: (
        "windows",
        "hashicorp/windows",
        "~> 0.1",
    ),
}


def _generate_provider_config(
    provider_type: ProviderType, profile: ScanProfile
) -> str:
    """Generate the provider configuration block for a given provider type.

    Uses credentials and endpoints from the ScanProfile to populate
    platform-specific configuration attributes.
    """
    tf_name = _PROVIDER_METADATA[provider_type][0]
    lines: list[str] = []
    lines.append(f'provider "{tf_name}" {{')

    if provider_type == ProviderType.KUBERNETES:
        host = profile.credentials.get("host", "")
        cluster_ca = profile.credentials.get("cluster_ca_certificate", "")
        token = profile.credentials.get("token", "")
        lines.append(f'  host                   = "{host}"')
        lines.append(f'  cluster_ca_certificate = "{cluster_ca}"')
        lines.append(f'  token                  = "{token}"')

    elif provider_type == ProviderType.DOCKER_SWARM:
        host = profile.credentials.get("host", "")
        cert_path = profile.credentials.get("cert_path", "")
        lines.append(f'  host      = "{host}"')
        lines.append(f'  cert_path = "{cert_path}"')

    elif provider_type == ProviderType.SYNOLOGY:
        url = profile.credentials.get("url", "")
        username = profile.credentials.get("username", "")
        password = profile.credentials.get("password", "")
        lines.append(f'  url      = "{url}"')
        lines.append(f'  username = "{username}"')
        lines.append(f'  password = "{password}"')

    elif provider_type == ProviderType.HARVESTER:
        kubeconfig = profile.credentials.get("kubeconfig", "")
        lines.append(f'  kubeconfig = "{kubeconfig}"')

    elif provider_type == ProviderType.BARE_METAL:
        endpoint = profile.credentials.get("endpoint", "")
        username = profile.credentials.get("username", "")
        password = profile.credentials.get("password", "")
        lines.append(f'  endpoint = "{endpoint}"')
        lines.append(f'  username = "{username}"')
        lines.append(f'  password = "{password}"')

    elif provider_type == ProviderType.WINDOWS:
        host = profile.credentials.get("host", "")
        username = profile.credentials.get("username", "")
        password = profile.credentials.get("password", "")
        lines.append(f'  host     = "{host}"')
        lines.append(f'  username = "{username}"')
        lines.append(f'  password = "{password}"')
        lines.append("")
        lines.append("  winrm {")
        winrm_port = profile.credentials.get("winrm_port", "5985")
        winrm_use_ssl = profile.credentials.get("winrm_use_ssl", "false")
        lines.append(f"    port    = {winrm_port}")
        lines.append(f"    use_ssl = {winrm_use_ssl}")
        lines.append("  }")

    lines.append("}")
    return "\n".join(lines)


def _generate_required_providers_block(
    provider_types: set[ProviderType],
) -> str:
    """Generate the terraform { required_providers { ... } } block."""
    lines: list[str] = []
    lines.append("terraform {")
    lines.append("  required_providers {")

    for provider_type in sorted(provider_types, key=lambda p: p.value):
        tf_name, source, version = _PROVIDER_METADATA[provider_type]
        lines.append(f"    {tf_name} = {{")
        lines.append(f'      source  = "{source}"')
        lines.append(f'      version = "{version}"')
        lines.append("    }")

    lines.append("  }")
    lines.append("}")
    return "\n".join(lines)


# ---------------------------------------------------------------------------
# ProviderBlockGenerator
# ---------------------------------------------------------------------------


class ProviderBlockGenerator:
    """Generates Terraform provider configuration blocks.

    Accepts a list of ScanProfiles and a set of ProviderTypes used in the
    generated code, and produces a providers.tf file containing:
    - A terraform { required_providers { ... } } block
    - Individual provider blocks with platform-specific configuration
    """

    def generate(
        self,
        profiles: list[ScanProfile],
        provider_types: set[ProviderType],
    ) -> GeneratedFile:
        """Generate the providers.tf file content.

        Args:
            profiles: List of ScanProfiles providing credentials/endpoints.
            provider_types: Set of distinct ProviderTypes used in the code.

        Returns:
            A GeneratedFile with filename "providers.tf" and the HCL content.
        """
        # Build a map from ProviderType -> first matching profile
        profile_map: dict[ProviderType, ScanProfile] = {}
        for profile in profiles:
            if profile.provider not in profile_map:
                profile_map[profile.provider] = profile

        sections: list[str] = []

        # 1. required_providers block
        sections.append(_generate_required_providers_block(provider_types))

        # 2. Individual provider configuration blocks
        for provider_type in sorted(provider_types, key=lambda p: p.value):
            profile = profile_map.get(provider_type)
            if profile is not None:
                sections.append(
                    _generate_provider_config(provider_type, profile)
                )
            else:
                # Generate a placeholder block if no profile matches
                tf_name = _PROVIDER_METADATA[provider_type][0]
                sections.append(
                    f'provider "{tf_name}" {{\n  # No profile provided\n}}'
                )

        content = "\n\n".join(sections) + "\n"

        return GeneratedFile(
            filename="providers.tf",
            content=content,
            resource_count=0,
        )