from __future__ import annotations

import re
from functools import lru_cache
from pathlib import Path
from urllib.parse import urlparse

from pydantic import Field, SecretStr, field_validator, model_validator
from pydantic_settings import BaseSettings, SettingsConfigDict

DEFAULT_TEMPLATE_DIR = Path(__file__).resolve().parents[1] / "templates" / "categories"


class Settings(BaseSettings):
    """Runtime configuration loaded from environment variables."""

    model_config = SettingsConfigDict(
        env_file=".env", env_file_encoding="utf-8", case_sensitive=False, extra="ignore"
    )

    app_name: str = "MediaRouter"
    app_version: str = "1.0.0"
    app_environment: str = "development"
    host: str = "0.0.0.0"
    port: int = 7860
    cors_allowed_origins: str = ""
    temp_dir: Path = Path("./temp")
    output_dir: Path = Path("./outputs")
    template_dir: Path = DEFAULT_TEMPLATE_DIR
    max_upload_size: int = Field(default=1_073_741_824, ge=1_048_576)
    max_duration_seconds: float = Field(default=21_600.0, gt=0)
    max_resolution_pixels: int = Field(default=33_177_600, ge=1)
    whisper_model: str = "small"
    cleanup_minutes: int = Field(default=60, ge=1)
    cleanup_interval_seconds: int = Field(default=60, ge=5)
    max_workers: int = Field(default=2, ge=1, le=32)
    log_level: str = "INFO"
    download_timeout_seconds: float = Field(default=300.0, gt=0)
    allow_private_urls: bool = False
    base_url: str = ""
    ffmpeg_binary: str = "ffmpeg"
    ffprobe_binary: str = "ffprobe"
    auth_enabled: bool = True
    database_url: str = "sqlite+aiosqlite:///./data/mediarouter.db"
    # Security/tenant schema creation is automatic only for SQLite local
    # development. PostgreSQL deployments must apply SQL migrations explicitly.
    security_auto_migrate: bool = False
    security_database_role: str = ""
    security_enforce_rls: bool = True
    auth_role_scopes: dict[str, list[str]] = Field(default_factory=dict)
    auth_bootstrap_key_hash: str = ""
    auth_bootstrap_key_prefix: str = ""
    auth_bootstrap_key_name: str = "Bootstrap Administrator"
    auth_bootstrap_environment: str = "live"
    auth_last_used_update_seconds: int = Field(default=60, ge=0, le=3600)
    auth_default_requests_per_minute: int = Field(default=100, ge=1, le=1_000_000)
    auth_default_concurrent_jobs: int = Field(default=10, ge=1, le=10_000)
    auth_default_uploads_per_hour: int = Field(default=20, ge=1, le=1_000_000)
    auth_default_processing_bytes_per_day: int = Field(default=107_374_182_400, ge=1_048_576)
    auth_trust_proxy_headers: bool = True
    mcp_stdio_api_key: SecretStr | None = None
    # Social Automation foundation. The existing database remains the default
    # local store; production Supabase/Postgres deployments should set a
    # dedicated async SQLAlchemy URL and apply the SQL migration out-of-band.
    social_enabled: bool = True
    social_database_url: str = ""
    # API requests use SOCIAL_DATABASE_URL with a non-BYPASSRLS role. Workers
    # use a separate, backend-only connection with the trusted role below.
    social_worker_database_url: str = ""
    social_tenant_database_role: str = ""
    social_worker_database_role: str = ""
    social_enforce_rls: bool = True
    social_auto_migrate: bool = False
    social_worker_enabled: bool = True
    social_scheduler_interval_seconds: int = Field(default=30, ge=5, le=3600)
    social_job_stale_after_seconds: int = Field(default=900, ge=60, le=86_400)
    social_publish_retry_limit: int = Field(default=5, ge=0, le=20)
    social_oauth_requests_per_hour: int = Field(default=30, ge=1, le=100_000)
    social_publish_requests_per_minute: int = Field(default=30, ge=1, le=100_000)
    social_schedule_requests_per_minute: int = Field(default=60, ge=1, le=100_000)
    social_analytics_requests_per_minute: int = Field(default=120, ge=1, le=100_000)
    social_oauth_encryption_key: SecretStr | None = None
    supabase_url: str = ""
    supabase_service_role_key: SecretStr | None = None
    supabase_vault_enabled: bool = False
    google_client_id: str = ""
    google_client_secret: SecretStr | None = None
    youtube_upload_chunk_bytes: int = Field(default=8 * 1024 * 1024, ge=256 * 1024)
    youtube_max_concurrent_uploads: int = Field(default=2, ge=1, le=32)
    youtube_request_timeout_seconds: float = Field(default=60.0, gt=0, le=600)
    youtube_processing_poll_seconds: int = Field(default=30, ge=5, le=3600)
    meta_client_id: str = ""
    meta_client_secret: SecretStr | None = None
    # META_APP_* is the public configuration contract. META_CLIENT_* remains
    # supported for deployments created during the social foundation phase.
    meta_app_id: str = ""
    meta_app_secret: SecretStr | None = None
    meta_graph_api_version: str = "v25.0"
    tiktok_client_key: str = ""
    tiktok_client_secret: SecretStr | None = None
    # Exact, backend-owned OAuth callback registered in TikTok Login Kit.
    # This is intentionally separate from the secret and is never a frontend
    # configuration value.
    tiktok_redirect_uri: str = ""
    # Direct Post requires TikTok Content Posting approval and an audited app.
    # Keep it fail-closed until an operator has confirmed that access.
    tiktok_direct_post_enabled: bool = False
    tiktok_upload_chunk_bytes: int = Field(default=10_000_000, ge=5_000_000, le=64_000_000)
    tiktok_request_timeout_seconds: float = Field(default=60.0, gt=0, le=600)
    tiktok_processing_poll_seconds: int = Field(default=30, ge=5, le=3600)
    linkedin_client_id: str = ""
    linkedin_client_secret: SecretStr | None = None
    # Exact backend callback registered in the LinkedIn Developer Portal.
    linkedin_redirect_uri: str = ""
    # Community Management posting is approval-gated. Keep it disabled until
    # the operator has confirmed the application products and write scopes in
    # LinkedIn Developer Portal.
    linkedin_publishing_enabled: bool = False
    linkedin_request_timeout_seconds: float = Field(default=60.0, gt=0, le=600)
    linkedin_media_processing_poll_seconds: int = Field(default=5, ge=1, le=300)
    linkedin_media_processing_timeout_seconds: int = Field(default=600, ge=30, le=3600)
    x_client_id: str = ""
    x_client_secret: SecretStr | None = None
    # Exact OAuth 2.0 callback registered for the confidential X Web App.
    x_redirect_uri: str = ""
    # X does not expose a dependable startup entitlement probe. Keep posting
    # fail-closed until an operator confirms the project has current write and
    # media access in the X Developer Console.
    x_publishing_enabled: bool = False
    x_upload_chunk_bytes: int = Field(default=5 * 1024 * 1024, ge=1_048_576, le=64 * 1024 * 1024)
    x_request_timeout_seconds: float = Field(default=60.0, gt=0, le=600)
    x_media_processing_poll_seconds: int = Field(default=5, ge=1, le=300)
    x_media_processing_timeout_seconds: int = Field(default=300, ge=30, le=3600)
    telegram_bot_token: SecretStr | None = None
    whatsapp_client_id: str = ""
    whatsapp_client_secret: SecretStr | None = None
    social_oauth_redirect_base_url: str = ""
    # Provider-neutral generation runtime. Providers remain optional and their
    # worker endpoints/tokens stay server-side only.
    generation_enabled: bool = True
    generation_job_retry_limit: int = Field(default=3, ge=0, le=20)
    # Shared remote-generation worker transport defaults. These do not enable
    # a provider and intentionally contain no worker URL or credentials.
    ai_worker_connect_timeout_seconds: float = Field(default=10.0, gt=0, le=300)
    ai_worker_request_timeout_seconds: float = Field(default=60.0, gt=0, le=3600)
    ai_worker_read_timeout_seconds: float = Field(default=300.0, gt=0, le=7200)
    ai_worker_max_retries: int = Field(default=3, ge=0, le=10)
    ai_worker_retry_backoff_seconds: float = Field(default=0.5, ge=0, le=60)
    # WAN is optional.  These values remain backend-only and are deliberately
    # not validated at Settings construction time: a bad optional worker
    # configuration must leave WAN unavailable without preventing unrelated
    # MediaRouter services from starting.
    wan_space_url: str = ""
    wan_space_token: SecretStr | None = None
    # Optional authenticated FLUX.2 Klein worker. Invalid configuration keeps
    # FLUX unavailable without affecting startup or other providers.
    flux_space_url: str = ""
    flux_space_token: SecretStr | None = None
    generation_worker_enabled: bool = True
    generation_worker_interval_seconds: float = Field(default=5.0, ge=0.5, le=3600)
    generation_worker_poll_backoff_seconds: float = Field(default=2.0, ge=0.5, le=300)
    generation_worker_batch_size: int = Field(default=8, ge=1, le=100)
    generation_job_stale_after_seconds: int = Field(default=900, ge=60, le=86_400)
    # Content Studio persistence/render safety limits. Rendering is optional
    # infrastructure; disabling its worker never prevents API startup.
    editor_state_max_bytes: int = Field(default=1_048_576, ge=16_384, le=16_777_216)
    render_worker_enabled: bool = True
    render_worker_interval_seconds: float = Field(default=2.0, ge=0.5, le=3600)
    render_job_stale_after_seconds: int = Field(default=900, ge=60, le=86_400)
    render_job_timeout_seconds: int = Field(default=7200, ge=60, le=86_400)
    render_job_retry_limit: int = Field(default=2, ge=0, le=10)
    render_max_active_jobs_per_project: int = Field(default=1, ge=1, le=10)
    render_max_tracks: int = Field(default=32, ge=1, le=256)
    render_max_clips: int = Field(default=500, ge=1, le=10_000)
    render_max_duration_seconds: int = Field(default=3600, ge=1, le=21_600)
    render_max_input_bytes: int = Field(default=4_294_967_296, ge=1_048_576)

    @field_validator("whisper_model")
    @classmethod
    def validate_whisper_model(cls, value: str) -> str:
        allowed = {"tiny", "base", "small", "medium", "large-v3"}
        if value not in allowed:
            raise ValueError(f"WHISPER_MODEL must be one of: {', '.join(sorted(allowed))}")
        return value

    @field_validator("log_level")
    @classmethod
    def normalize_log_level(cls, value: str) -> str:
        normalized = value.upper()
        allowed = {"DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"}
        if normalized not in allowed:
            raise ValueError(f"LOG_LEVEL must be one of: {', '.join(sorted(allowed))}")
        return normalized

    @field_validator("app_environment")
    @classmethod
    def normalize_app_environment(cls, value: str) -> str:
        normalized = value.strip().lower()
        if normalized not in {"development", "test", "production"}:
            raise ValueError("APP_ENVIRONMENT must be development, test, or production")
        return normalized

    @property
    def allowed_cors_origins(self) -> tuple[str, ...]:
        """Return validated, normalized origins for Starlette CORS middleware."""

        origins: list[str] = []
        for configured in self.cors_allowed_origins.split(","):
            origin = configured.strip().rstrip("/")
            if not origin:
                continue
            parsed = urlparse(origin)
            if (
                "*" in origin
                or parsed.scheme not in {"http", "https"}
                or not parsed.netloc
                or parsed.username
                or parsed.password
                or parsed.path
                or parsed.params
                or parsed.query
                or parsed.fragment
            ):
                raise ValueError(
                    "CORS_ALLOWED_ORIGINS must contain comma-separated HTTP(S) origins"
                )
            if origin not in origins:
                origins.append(origin)
        return tuple(origins)

    @model_validator(mode="after")
    def validate_production_contract(self) -> Settings:
        """Fail clearly when the Docker production boundary is unsafe.

        Local development and tests retain the established SQLite defaults.
        The production Dockerfile sets ``APP_ENVIRONMENT=production``, making
        external PostgreSQL, RLS, explicit migrations, authentication, and an
        exact frontend CORS origin mandatory at process import/startup.
        """

        origins = self.allowed_cors_origins
        if self.app_environment != "production":
            return self

        errors: list[str] = []
        if not self._is_external_postgres(self.database_url):
            errors.append("DATABASE_URL must use an external PostgreSQL database in production")
        if self.security_auto_migrate:
            errors.append("SECURITY_AUTO_MIGRATE must be false in production")
        if not self.security_enforce_rls:
            errors.append("SECURITY_ENFORCE_RLS must be true in production")
        if not self.security_database_role.strip():
            errors.append("SECURITY_DATABASE_ROLE is required in production")
        if not self.auth_enabled:
            errors.append("AUTH_ENABLED must be true in production")
        if not origins:
            errors.append("CORS_ALLOWED_ORIGINS must include the HTTPS Vercel frontend origin")
        elif any(urlparse(origin).scheme != "https" for origin in origins):
            errors.append("CORS_ALLOWED_ORIGINS must use HTTPS in production")

        if self.social_auto_migrate:
            errors.append("SOCIAL_AUTO_MIGRATE must be false in production")
        if self.social_enabled:
            if not self.social_database_url.strip() or not self._is_external_postgres(
                self.social_database_url
            ):
                errors.append(
                    "SOCIAL_DATABASE_URL must use an explicit external PostgreSQL tenant connection"
                )
            if not self.social_tenant_database_role.strip():
                errors.append("SOCIAL_TENANT_DATABASE_ROLE is required when social is enabled")
            if not self._is_external_postgres(self.social_worker_database_url):
                errors.append(
                    "SOCIAL_WORKER_DATABASE_URL must use an external PostgreSQL worker connection"
                )
            if not self.social_worker_database_role.strip():
                errors.append("SOCIAL_WORKER_DATABASE_ROLE is required when social is enabled")
            if not self.social_enforce_rls:
                errors.append("SOCIAL_ENFORCE_RLS must be true when social is enabled")

        if errors:
            raise ValueError("Invalid production configuration: " + "; ".join(errors))
        return self

    @staticmethod
    def _is_external_postgres(value: str) -> bool:
        configured = value.strip()
        if not configured:
            return False
        parsed = urlparse(configured)
        if parsed.scheme not in {"postgres", "postgresql", "postgresql+asyncpg"}:
            return False
        hostname = (parsed.hostname or "").lower()
        return bool(hostname and hostname not in {"localhost", "127.0.0.1", "::1"})

    def ensure_directories(self) -> None:
        self.temp_dir.mkdir(parents=True, exist_ok=True)
        self.output_dir.mkdir(parents=True, exist_ok=True)
        sqlite_prefixes = ("sqlite+aiosqlite:///", "sqlite:///")
        for url in {self.database_url, self.resolved_social_database_url}:
            for prefix in sqlite_prefixes:
                if url.startswith(prefix):
                    database_path = url.removeprefix(prefix)
                    if database_path and database_path != ":memory:":
                        Path(database_path).expanduser().resolve().parent.mkdir(
                            parents=True, exist_ok=True
                        )
                    break

    @property
    def resolved_social_database_url(self) -> str:
        """Use an explicit social database when configured, otherwise local DB."""
        return self.social_database_url.strip() or self.database_url

    @property
    def resolved_meta_app_id(self) -> str:
        return self.meta_app_id.strip() or self.meta_client_id.strip()

    @property
    def resolved_meta_app_secret(self) -> SecretStr | None:
        return self.meta_app_secret or self.meta_client_secret

    @field_validator("auth_bootstrap_environment")
    @classmethod
    def validate_auth_environment(cls, value: str) -> str:
        normalized = value.strip().lower()
        if normalized not in {"live", "test"}:
            raise ValueError("AUTH_BOOTSTRAP_ENVIRONMENT must be live or test")
        return normalized

    @field_validator("youtube_upload_chunk_bytes")
    @classmethod
    def validate_youtube_chunk_size(cls, value: int) -> int:
        # Google resumable uploads require every non-final chunk to be aligned
        # to 256 KiB. Keeping the constraint at configuration time avoids a
        # late failure after an upload session was already created.
        if value % (256 * 1024):
            raise ValueError("YOUTUBE_UPLOAD_CHUNK_BYTES must be a multiple of 262144")
        return value

    @field_validator("meta_graph_api_version")
    @classmethod
    def validate_meta_graph_api_version(cls, value: str) -> str:
        normalized = value.strip()
        if not re.fullmatch(r"v[0-9]+\.[0-9]+", normalized):
            raise ValueError("META_GRAPH_API_VERSION must use the form vNN.N")
        return normalized

    @field_validator("tiktok_redirect_uri")
    @classmethod
    def validate_tiktok_redirect_uri(cls, value: str) -> str:
        normalized = value.strip()
        if not normalized:
            return ""
        parsed = urlparse(normalized)
        local_hosts = {"localhost", "127.0.0.1", "::1"}
        if (
            not parsed.netloc
            or parsed.username
            or parsed.password
            or parsed.query
            or parsed.fragment
            or parsed.path != "/v1/social/accounts/tiktok/callback"
            or (parsed.scheme != "https" and parsed.hostname not in local_hosts)
        ):
            raise ValueError(
                "TIKTOK_REDIRECT_URI must be the HTTPS MediaRouter TikTok callback URI"
            )
        return normalized

    @field_validator("x_redirect_uri")
    @classmethod
    def validate_x_redirect_uri(cls, value: str) -> str:
        normalized = value.strip()
        if not normalized:
            return ""
        parsed = urlparse(normalized)
        local_hosts = {"localhost", "127.0.0.1", "::1"}
        if (
            not parsed.netloc
            or parsed.username
            or parsed.password
            or parsed.query
            or parsed.fragment
            or parsed.path != "/v1/social/accounts/x/callback"
            or not (
                parsed.scheme == "https"
                or (parsed.scheme == "http" and parsed.hostname in local_hosts)
            )
        ):
            raise ValueError("X_REDIRECT_URI must be the HTTPS MediaRouter X callback URI")
        return normalized

    @field_validator("linkedin_redirect_uri")
    @classmethod
    def validate_linkedin_redirect_uri(cls, value: str) -> str:
        normalized = value.strip()
        if not normalized:
            return ""
        parsed = urlparse(normalized)
        local_hosts = {"localhost", "127.0.0.1", "::1"}
        if (
            not parsed.netloc
            or parsed.username
            or parsed.password
            or parsed.query
            or parsed.fragment
            or parsed.path != "/v1/social/accounts/linkedin/callback"
            or not (
                parsed.scheme == "https"
                or (parsed.scheme == "http" and parsed.hostname in local_hosts)
            )
        ):
            raise ValueError(
                "LINKEDIN_REDIRECT_URI must be the HTTPS MediaRouter LinkedIn callback URI"
            )
        return normalized


@lru_cache
def get_settings() -> Settings:
    settings = Settings()
    settings.ensure_directories()
    return settings