"""Configuration for the template-agnostic v2 backend.

All values are overridable via environment variables (prefix-free) or a ``.env``
file at the repository root. See the package README for the deployment model.
"""

from __future__ import annotations

from functools import lru_cache
from pathlib import Path

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict

# backend/config.py -> repo root is one level up from this package.
REPO_ROOT = Path(__file__).resolve().parents[1]


class Settings(BaseSettings):
    """Central v2 settings object."""

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

    # ── LLM (OpenAI) ─────────────────────────────────────────────────────────
    openai_api_key: str = Field(default="", description="OpenAI API key")
    mapping_model: str = Field(
        default="gpt-4o-mini",
        description="Model used to map surveyor notes onto retrieved master paragraphs.",
    )
    discovery_model: str = Field(
        default="gpt-4o-mini",
        description="Model used for master-template schema discovery (JSON mode).",
    )
    grounding_model: str = Field(
        default="gpt-4o-mini",
        description="Model used for the PII / grounding audit pass.",
    )
    openai_request_timeout_seconds: float = Field(
        default=60.0,
        ge=5.0,
        le=600.0,
        description="Hard timeout for OpenAI chat and embedding HTTP calls (seconds).",
    )
    openai_pipeline_timeout_seconds: float = Field(
        default=20.0,
        ge=5.0,
        le=120.0,
        description=(
            "Strict per-call timeout (seconds) for chat/embeddings inside the "
            "report generation pipeline."
        ),
    )
    max_concurrent_llm_calls: int = Field(
        default=10,
        ge=1,
        le=100,
        description=(
            "Maximum concurrent in-flight OpenAI chat completion HTTP requests "
            "across parallel section workers."
        ),
    )
    openai_rate_limit_max_retries: int = Field(
        default=5,
        ge=0,
        le=20,
        description="Retry attempts after OpenAI HTTP 429 rate-limit responses.",
    )
    openai_rate_limit_backoff_base_seconds: float = Field(
        default=1.0,
        ge=0.1,
        le=60.0,
        description="Initial exponential backoff base (seconds) for 429 retries.",
    )
    openai_rate_limit_backoff_max_seconds: float = Field(
        default=60.0,
        ge=1.0,
        le=300.0,
        description="Maximum backoff delay (seconds) between 429 retries.",
    )

    # ── Embeddings (local MiniLM default; OpenAI optional) ───────────────────
    embedding_provider: str = Field(
        default="local",
        description="Embedding backend: 'local' (sentence-transformers) or 'openai'.",
    )
    local_embedding_model: str = Field(
        default="all-MiniLM-L6-v2",
        description="sentence-transformers model used when embedding_provider='local'.",
    )
    openai_embedding_model: str = Field(
        default="text-embedding-3-small",
        description="OpenAI embedding model used when embedding_provider='openai'.",
    )

    # ── PII scrubbing ────────────────────────────────────────────────────────
    spacy_model: str = Field(
        default="en_core_web_trf",
        description=(
            "spaCy model used for the NER pass of PII scrubbing. When unavailable, the "
            "scrubber falls back to its regex layer only."
        ),
    )
    pii_use_spacy: bool = Field(
        default=True,
        description="Enable the spaCy NER pass on top of the always-on regex pass.",
    )

    # ── Operator bundle (Master Standard report and paragraphs/) ─────────────
    master_template_dir: str = Field(
        default="Master Standard report and paragraphs",
        description="Folder holding the report template PDF and standard-paragraphs Word file.",
    )
    report_template_filename: str = Field(
        default="SAMPLE LEVEL 3 REPORT NCS.pdf",
        description=(
            "Report template (PDF): defines section structure, order and ratings. "
            "Schema discovery reads this file."
        ),
    )
    standard_paragraphs_filename: str = Field(
        default="HB-BS STANDARD PARAS v6 Sept 2015.doc",
        description=(
            "Standard paragraphs (Word): firm-approved boilerplate wording per section. "
            "Ingested into the MASTER RAG tier."
        ),
    )
    # Backward-compatible alias for the standard-paragraphs file.
    master_template_filename: str = Field(
        default="HB-BS STANDARD PARAS v6 Sept 2015.doc",
        description="Deprecated alias for standard_paragraphs_filename.",
    )
    master_template_auto_ingest: bool = Field(
        default=False,
        description=(
            "Ingest the operator's shared standard-paragraph master into the MASTER "
            "RAG tier on startup. Default False: in the per-tenant model every tenant "
            "supplies its own past reports (REFERENCE tier) and generation is sourced "
            "exclusively from those at all interference levels. Enable only if a firm "
            "wants a shared boilerplate master seeded for the default tenant. The "
            "canonical RICS L3 schema is always installed regardless of this flag."
        ),
    )
    master_template_prebuilt_schema: str = Field(
        default="",
        description="Optional path to a prebuilt schema.json; skips discovery when set and present.",
    )
    master_template_prebuilt_faiss: str = Field(
        default="",
        description="Optional path to a prebuilt MASTER FAISS dir; skips embedding when set and present.",
    )
    master_template_upload_enabled: bool = Field(
        default=False,
        description="Enable the gated admin override routes for replacing the master at runtime.",
    )

    # ── Optional reference uploads (past completed reports, style only) ────────
    reference_auto_ingest_enabled: bool = Field(
        default=False,
        description=(
            "When true, scan reference_auto_ingest_dir for extra past reports. "
            "The report-template PDF and standard-paragraphs Word file are never "
            "ingested as references."
        ),
    )
    reference_auto_ingest_dir: str = Field(
        default="",
        description="Folder to scan for reference docs; empty means use master_template_dir.",
    )
    reference_auto_ingest_globs: str = Field(
        default="*.pdf,*.docx,*.doc",
        description="Comma-separated globs scanned for reference docs (master filename excluded).",
    )
    # ── RAG / retrieval ──────────────────────────────────────────────────────
    data_dir: str = Field(
        default_factory=lambda: str(Path.home() / ".rics_v2"),
        description="Root directory for per-tenant schema + FAISS artifacts.",
    )
    default_tenant_id: str = Field(
        default="default",
        description="Tenant that receives the operator master at startup.",
    )
    retrieval_top_k: int = Field(default=5, ge=1, le=50)
    reference_baseline_top_k: int = Field(
        default=4,
        ge=1,
        le=50,
        description="Top REFERENCE-tier blocks retrieved as stylistic baseline scaffolding.",
    )
    retrieval_section_boost: float = Field(
        default=0.25,
        ge=0.0,
        le=1.0,
        description="FAISS score boost when chunk section_id matches the alias-resolved id.",
    )
    retrieval_lexical_boost: float = Field(
        default=0.04,
        ge=0.0,
        le=0.5,
        description="Per shared content-token boost when reranking paragraphs against notes.",
    )
    note_routing_mode: str = Field(
        default="keyword",
        description="Note routing: 'keyword' (deterministic regex) or 'rag' (embedding anchors).",
    )
    note_rag_match_min_score: float = Field(
        default=0.72,
        ge=0.0,
        le=1.0,
        description=(
            "Minimum cosine similarity for a surveyor note to be mapped onto a "
            "canonical section anchor. Below this, the note is surfaced as UNASSIGNED."
        ),
    )
    note_rag_ambiguity_margin: float = Field(
        default=0.05,
        ge=0.0,
        le=0.5,
        description=(
            "Minimum cosine gap between the top two section-anchor matches. When "
            "the margin is narrower, the note is treated as ambiguous and UNASSIGNED."
        ),
    )
    note_baseline_lexical_min_overlap: float = Field(
        default=0.12,
        ge=0.0,
        le=1.0,
        description=(
            "Minimum token-overlap ratio between a note and the section baseline "
            "to allow in-place mapping without a strong per-note RAG hit."
        ),
    )
    paragraph_min_chars: int = Field(default=80, ge=1, le=2000)
    paragraph_max_chars: int = Field(default=1200, ge=100, le=4000)
    chunk_overlap: int = Field(default=120, ge=0, le=1000)
    reference_paragraph_max_chars: int = Field(
        default=8000,
        ge=500,
        le=20000,
        description="Max characters per REFERENCE-tier chunk (long-form past report sections).",
    )
    reference_chunk_overlap: int = Field(
        default=1500,
        ge=0,
        le=5000,
        description="Character overlap when splitting oversized REFERENCE sections.",
    )
    reference_section_complete_enabled: bool = Field(
        default=True,
        description=(
            "Assemble the WHOLE past-report section as the mapping baseline (every "
            "chunk for the chosen source+section, in document order) rather than only "
            "the top-K semantically nearest chunks. Also lets a section that exists in "
            "the index but was missed by similarity search fall back to a metadata "
            "fetch before degrading to NOTES_ONLY. Disable to restore top-K-only."
        ),
    )
    reference_section_complete_max_chars: int = Field(
        default=12000,
        ge=1000,
        le=40000,
        description=(
            "Safety cap on an assembled section-complete baseline. Chunks are added "
            "in document order until this budget is reached, bounding the mapping "
            "prompt while still covering long (30–50 line) past-report sections."
        ),
    )

    # ── Generation behaviour ─────────────────────────────────────────────────
    default_survey_level: int = Field(
        default=3,
        ge=1,
        le=3,
        description="Default RICS survey tier (Level 3 → full in-place narrative edit).",
    )
    composition_mode: str = Field(
        default="in_place_edit",
        description="Report composition strategy: style-informed in-place edit on REFERENCE baseline.",
    )
    max_tokens_mapping: int = Field(default=4096, ge=256, le=16000)
    max_tokens_grounding: int = Field(default=1024, ge=256, le=8000)
    max_tokens_discovery: int = Field(default=4000, ge=512, le=16000)
    notes_expansion_enabled: bool = Field(
        default=False,
        description="Run the optional notes-expander pass before mapping.",
    )
    use_llm_paragraph_mapping: bool = Field(
        default=True,
        description=(
            "Style-informed in-place edit on the REFERENCE baseline using the "
            "mapping editor prompt. When false, deterministic weave only."
        ),
    )
    grounding_enabled: bool = Field(
        default=True,
        description="Run the grounding/PII audit on each mapped section before assembly.",
    )
    grounding_alert_threshold: float = Field(
        default=0.2,
        ge=0.0,
        le=1.0,
        description=(
            "Fraction of sections needing review above which the preview flags "
            "manual_review_required."
        ),
    )
    ai_transparency_footer_enabled: bool = Field(
        default=False,
        description="Append an AI transparency footer to generated DOCX when enabled.",
    )
    template_docx_path: str = Field(
        default="",
        description="Optional branded DOCX template path for report export.",
    )

    # ── Report post-processing (final cleanup pass) ───────────────────────────
    postprocess_enabled: bool = Field(
        default=True,
        description="Master switch for the final report post-processing/normalisation pass.",
    )
    dedup_similarity_threshold: float = Field(
        default=0.85,
        ge=0.0,
        le=1.0,
        description="Character-trigram Jaccard threshold for near-duplicate paragraph removal (lower = more aggressive).",
    )
    extra_header_patterns: list[str] = Field(
        default_factory=list,
        description="Firm-specific header/artifact regex strings to strip during post-processing (keeps the pipeline firm-agnostic).",
    )
    postprocess_placeholder_pattern: str = Field(
        default=r"\[{1,2}REDACTED_[A-Z]+(?:_\d+)?\]{1,2}",
        description="Regex matching redaction tokens for post-processing grammar repair.",
    )
    postprocess_debug: bool = Field(
        default=False,
        description="When true, the post-processor prints a before/after preview to stdout.",
    )

    # ── Property-type retrieval guard ─────────────────────────────────────────
    property_guard_enabled: bool = Field(
        default=True,
        description="Reject retrieved paragraphs whose terminology is incompatible with the property type (e.g. flat content in a house report).",
    )
    property_blocklist_extra_terms: list[str] = Field(
        default_factory=list,
        description="Additional firm-specific terms that mark a retrieved paragraph as property-incompatible.",
    )

    # ── Upload limits (batch + ZIP + notes extract) ───────────────────────────
    max_single_upload_bytes: int = Field(
        default=50 * 1024 * 1024,
        ge=1024 * 1024,
        le=200 * 1024 * 1024,
        description="Max bytes per uploaded reference file (single or inside ZIP).",
    )
    max_zip_members: int = Field(
        default=40,
        ge=1,
        le=200,
        description="Max non-directory entries allowed inside an uploaded ZIP.",
    )
    max_zip_uncompressed_bytes: int = Field(
        default=200 * 1024 * 1024,
        ge=1024 * 1024,
        le=1024 * 1024 * 1024,
        description="Max total uncompressed size of all files in a ZIP.",
    )
    max_notes_extract_bytes: int = Field(
        default=10 * 1024 * 1024,
        ge=64 * 1024,
        le=50 * 1024 * 1024,
        description="Max bytes for /extract-notes uploads.",
    )

    # ── Section photos & vision ────────────────────────────────────────────────
    max_section_photo_bytes: int = Field(
        default=8 * 1024 * 1024,
        ge=256 * 1024,
        le=50 * 1024 * 1024,
        description="Max bytes per uploaded section photo.",
    )
    max_section_photos_per_section: int = Field(
        default=5,
        ge=0,
        le=50,
        description="Max photos stored per report section.",
    )
    max_section_photos_for_ai: int = Field(
        default=2,
        ge=0,
        le=10,
        description="Max photos per section the user may select for AI vision analysis.",
    )
    section_photo_vision_enabled: bool = Field(
        default=True,
        description="When true and OpenAI is configured, analyze selected section photos at generation.",
    )
    vision_model: str = Field(
        default="gpt-4o",
        description="OpenAI vision-capable model for section photo analysis.",
    )
    vision_max_tokens: int = Field(
        default=1200,
        ge=256,
        le=4096,
        description="Token budget for a section photo vision analysis call.",
    )
    vision_timeout_seconds: float = Field(
        default=90.0,
        ge=10.0,
        le=300.0,
        description="Hard timeout per vision API call (seconds).",
    )
    vision_max_observations: int = Field(
        default=12,
        ge=4,
        le=40,
        description="Max observation lines merged from vision per section.",
    )

    # ── Auth ─────────────────────────────────────────────────────────────────
    jwt_secret: str = Field(
        default="change-me-in-production",
        description="HMAC secret for signing tenant JWTs.",
    )
    jwt_algorithm: str = Field(default="HS256")
    jwt_expiry_minutes: int = Field(default=60 * 24, ge=5, le=60 * 24 * 30)
    admin_token: str = Field(
        default="",
        description="Static admin token required (in addition to JWT) for /admin routes.",
    )

    # ── Helpers ──────────────────────────────────────────────────────────────
    def resolve_path(self, value: str | Path) -> Path:
        """Resolve a possibly repo-relative path to an absolute path."""
        p = Path(value)
        return p if p.is_absolute() else (REPO_ROOT / p)

    @property
    def report_template_path(self) -> Path:
        """Absolute path to the report template (PDF) — schema authority."""
        return self.resolve_path(self.master_template_dir) / self.report_template_filename

    @property
    def standard_paragraphs_path(self) -> Path:
        """Absolute path to the standard-paragraphs Word file — MASTER RAG authority."""
        name = self.standard_paragraphs_filename or self.master_template_filename
        return self.resolve_path(self.master_template_dir) / name

    @property
    def master_template_path(self) -> Path:
        """Backward-compatible alias for :attr:`standard_paragraphs_path`."""
        return self.standard_paragraphs_path

    @property
    def reference_dir_path(self) -> Path:
        """Absolute path to the folder scanned for reference auto-ingest."""
        target = self.reference_auto_ingest_dir or self.master_template_dir
        return self.resolve_path(target)

    @property
    def data_dir_path(self) -> Path:
        return self.resolve_path(self.data_dir)

    @property
    def rag_top_k(self) -> int:
        """Spec alias for :attr:`retrieval_top_k`."""
        return self.retrieval_top_k

    @property
    def confidence_threshold(self) -> float:
        """Alias for per-note REFERENCE match gate (CURSOR_REFACTOR parity)."""
        return self.note_rag_match_min_score

    @property
    def branded_template_path(self) -> Path | None:
        if not self.template_docx_path.strip():
            return None
        p = self.resolve_path(self.template_docx_path)
        return p if p.is_file() else None


@lru_cache
def get_settings() -> Settings:
    """Cached settings singleton."""
    return Settings()


settings = get_settings()